cooperative motion and task planning under …introduction nominal scenario recon guration...
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Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Cooperative Motion and Task PlanningUnder Temporal Tasks
Meng Guo
Automatic Control Lab EESRoyal Institute of Technology KTH Sweden
Licentiate Seminar
Meng Guo Licentiate Seminar 1
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 2
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
MotivationIndustrial and domestic robots1 boosted by
I Development of digital processing unitsbull more powerful in speed and capacity
bull more affordable
I Wireless communication technologybull potentially connects the robots
bull integrates with other ldquosmartrdquo devices
1Gostai Roomba Romo Amigo service robotsMeng Guo Licentiate Seminar 3
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
MotivationIndustrial and domestic robots1 boosted by
I Development of digital processing unitsbull more powerful in speed and capacity
bull more affordable
I Wireless communication technologybull potentially connects the robots
bull integrates with other ldquosmartrdquo devices
1Gostai Roomba Romo Amigo service robotsMeng Guo Licentiate Seminar 3
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-users
bull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planning
bull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Multi-agent System
I Multi-agent system to solve a global task
bull decompose into sub-tasks
bull top-down tightly-coupled
I Multi-agent system with local tasks
bull favour individual interests
bull bottom-up loosely-coupled
Meng Guo Licentiate Seminar 7
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 2
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
MotivationIndustrial and domestic robots1 boosted by
I Development of digital processing unitsbull more powerful in speed and capacity
bull more affordable
I Wireless communication technologybull potentially connects the robots
bull integrates with other ldquosmartrdquo devices
1Gostai Roomba Romo Amigo service robotsMeng Guo Licentiate Seminar 3
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
MotivationIndustrial and domestic robots1 boosted by
I Development of digital processing unitsbull more powerful in speed and capacity
bull more affordable
I Wireless communication technologybull potentially connects the robots
bull integrates with other ldquosmartrdquo devices
1Gostai Roomba Romo Amigo service robotsMeng Guo Licentiate Seminar 3
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-users
bull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planning
bull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Multi-agent System
I Multi-agent system to solve a global task
bull decompose into sub-tasks
bull top-down tightly-coupled
I Multi-agent system with local tasks
bull favour individual interests
bull bottom-up loosely-coupled
Meng Guo Licentiate Seminar 7
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
MotivationIndustrial and domestic robots1 boosted by
I Development of digital processing unitsbull more powerful in speed and capacity
bull more affordable
I Wireless communication technologybull potentially connects the robots
bull integrates with other ldquosmartrdquo devices
1Gostai Roomba Romo Amigo service robotsMeng Guo Licentiate Seminar 3
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
MotivationIndustrial and domestic robots1 boosted by
I Development of digital processing unitsbull more powerful in speed and capacity
bull more affordable
I Wireless communication technologybull potentially connects the robots
bull integrates with other ldquosmartrdquo devices
1Gostai Roomba Romo Amigo service robotsMeng Guo Licentiate Seminar 3
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-users
bull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planning
bull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Multi-agent System
I Multi-agent system to solve a global task
bull decompose into sub-tasks
bull top-down tightly-coupled
I Multi-agent system with local tasks
bull favour individual interests
bull bottom-up loosely-coupled
Meng Guo Licentiate Seminar 7
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
MotivationIndustrial and domestic robots1 boosted by
I Development of digital processing unitsbull more powerful in speed and capacity
bull more affordable
I Wireless communication technologybull potentially connects the robots
bull integrates with other ldquosmartrdquo devices
1Gostai Roomba Romo Amigo service robotsMeng Guo Licentiate Seminar 3
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-users
bull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planning
bull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Multi-agent System
I Multi-agent system to solve a global task
bull decompose into sub-tasks
bull top-down tightly-coupled
I Multi-agent system with local tasks
bull favour individual interests
bull bottom-up loosely-coupled
Meng Guo Licentiate Seminar 7
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-users
bull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planning
bull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Multi-agent System
I Multi-agent system to solve a global task
bull decompose into sub-tasks
bull top-down tightly-coupled
I Multi-agent system with local tasks
bull favour individual interests
bull bottom-up loosely-coupled
Meng Guo Licentiate Seminar 7
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-users
bull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planning
bull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Multi-agent System
I Multi-agent system to solve a global task
bull decompose into sub-tasks
bull top-down tightly-coupled
I Multi-agent system with local tasks
bull favour individual interests
bull bottom-up loosely-coupled
Meng Guo Licentiate Seminar 7
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-users
bull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planning
bull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Multi-agent System
I Multi-agent system to solve a global task
bull decompose into sub-tasks
bull top-down tightly-coupled
I Multi-agent system with local tasks
bull favour individual interests
bull bottom-up loosely-coupled
Meng Guo Licentiate Seminar 7
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motivation
I Imagine several care robots in your house
bull ldquoAmigo go to the kitchen find anapple and bring it to merdquo
bull ldquoGostai keep an eye on the kids inthe living room and bedroomrdquo
bull ldquoAmigo put all the toys in thebasketrdquo
bull middot middot middot
Meng Guo Licentiate Seminar 4
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-users
bull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planning
bull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Multi-agent System
I Multi-agent system to solve a global task
bull decompose into sub-tasks
bull top-down tightly-coupled
I Multi-agent system with local tasks
bull favour individual interests
bull bottom-up loosely-coupled
Meng Guo Licentiate Seminar 7
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-users
bull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planning
bull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Multi-agent System
I Multi-agent system to solve a global task
bull decompose into sub-tasks
bull top-down tightly-coupled
I Multi-agent system with local tasks
bull favour individual interests
bull bottom-up loosely-coupled
Meng Guo Licentiate Seminar 7
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots that
bull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planning
bull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Multi-agent System
I Multi-agent system to solve a global task
bull decompose into sub-tasks
bull top-down tightly-coupled
I Multi-agent system with local tasks
bull favour individual interests
bull bottom-up loosely-coupled
Meng Guo Licentiate Seminar 7
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planning
bull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Multi-agent System
I Multi-agent system to solve a global task
bull decompose into sub-tasks
bull top-down tightly-coupled
I Multi-agent system with local tasks
bull favour individual interests
bull bottom-up loosely-coupled
Meng Guo Licentiate Seminar 7
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Challenges
Challenges for system engineers (us)
I Provide the non-expert end-usersbull a formal but flexible way to specify daily tasks
bull task execution status as feedback
I Design algorithms for robots thatbull synthesize and execute a plan to satisfy the task
bull without or with minimal human intervention
bull accommodate changes in the workspace
bull initiate communication with other devices
bull handle collaborative tasks
Meng Guo Licentiate Seminar 5
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planning
bull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Multi-agent System
I Multi-agent system to solve a global task
bull decompose into sub-tasks
bull top-down tightly-coupled
I Multi-agent system with local tasks
bull favour individual interests
bull bottom-up loosely-coupled
Meng Guo Licentiate Seminar 7
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planning
bull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Multi-agent System
I Multi-agent system to solve a global task
bull decompose into sub-tasks
bull top-down tightly-coupled
I Multi-agent system with local tasks
bull favour individual interests
bull bottom-up loosely-coupled
Meng Guo Licentiate Seminar 7
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Multi-agent System
I Multi-agent system to solve a global task
bull decompose into sub-tasks
bull top-down tightly-coupled
I Multi-agent system with local tasks
bull favour individual interests
bull bottom-up loosely-coupled
Meng Guo Licentiate Seminar 7
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis
2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Multi-agent System
I Multi-agent system to solve a global task
bull decompose into sub-tasks
bull top-down tightly-coupled
I Multi-agent system with local tasks
bull favour individual interests
bull bottom-up loosely-coupled
Meng Guo Licentiate Seminar 7
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Background
I Motion and task planningbull motion plan of dynamic systems2
bull task plan for discrete-event systems3
I Model checkingbull for verification4
bull for plan synthesis2S M LaValle Planning algorithms 20063M Ghallab et al Automated planning theory amp practice 20044C Baier J-P Katoen Principles of model checking 2008
Meng Guo Licentiate Seminar 6
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Multi-agent System
I Multi-agent system to solve a global task
bull decompose into sub-tasks
bull top-down tightly-coupled
I Multi-agent system with local tasks
bull favour individual interests
bull bottom-up loosely-coupled
Meng Guo Licentiate Seminar 7
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Multi-agent System
I Multi-agent system to solve a global task
bull decompose into sub-tasks
bull top-down tightly-coupled
I Multi-agent system with local tasks
bull favour individual interests
bull bottom-up loosely-coupled
Meng Guo Licentiate Seminar 7
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Main Contributions
I Reconfiguration for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Motion and Action
Planning under LTL Specification using Navigation Functions andAction Description Language IROS Japan 2013
bull M Guo and D V Dimarogonas Reconfiguration in Motion Planningof Single- and Multi-agent Systems under Infeasible Local LTLSpecifications CDC Italy 2013
I Real-time adaptation for single- and multi-agent systemsbull M Guo K H Johansson and D V Dimarogonas Revising Motion
Planning under Linear Temporal Logic Specifications in PartiallyKnown Workspaces ICRA Germany 2013
bull M Guo and D V Dimarogonas Distributed Plan Reconfiguration viaKnowledge Transfer in Multi-agent Systems under Local LTLSpecifications ICRA Hongkong 2014
bull M Guo and D V Dimarogonas Multi-agent Plan Reconfigurationunder Local LTL Specifications IJRR Submitted
Meng Guo Licentiate Seminar 8
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 9
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW
bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion Abstraction
I Abstracted as the weighted finite transition system (FTS)
Tc = (Π minusrarrc Π0 AP Lc Wc)
where the finite regions Π = π1 π2 middot middot middot πW bull properties of interest AP = APr capAPpbull Π0 initial states
bull minusrarrcsube ΠtimesΠ control-driven transition
bull Lc Π rarr 2AP labelling function
bull Wc ΠtimesΠ rarr R+ weight function
I Examples
1
2 3
4
Meng Guo Licentiate Seminar 10
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Abstraction Outcome
Meng Guo Licentiate Seminar 11
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Temporal Task Specification
How to formally specify the task
I Language Linear-time Temporal Logic (LTL) formula
I Syntax
ϕ = True | a | ϕ1 or ϕ2 | notϕ | copy ϕ | ϕ1 Uϕ2
I Semantics5
I Specified over AP
I To specify control tasks
bull Safety notϕ1 Order diams(ϕ1 and diams(ϕ2 and diamsϕ3))
bull Response ϕ1 rArr ϕ2 Liveness diamsϕ1
5C Baier J-P Katoen Principles of model checking 2008Meng Guo Licentiate Seminar 12
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)
I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Task Interpretation
I ldquogo to the kitchen find anapple and bring it to merdquo
I ldquokeep an eye on the kids inthe living room andbedroomrdquo
I ldquoput all the toys in thebasketrdquo
I middot middot middot
I ϕ =diams((Kitand PickApp)anddiams(Liv)
)I ϕ = diamsLiv anddiamsBed
I ϕ = diams
(PickToyrarr(
notPickToy U (Bas and
DropToy)))
I middot middot middot
Meng Guo Licentiate Seminar 13
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
Given the FTS Tc and the LTL task ϕ
I Synthesize a discrete plan that satisfies ϕ
I Construct the hybrid control strategy to execute thederived plan
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
0 500 1000 1500 20000
500
1000
1500
2000
Meng Guo Licentiate Seminar 14
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Nominal Solution Outline
I Automata-based model-checking algorithm6
I Hybrid controller synthesis7
6C Baier J-P Katoen Principles of model checking 20087G E Fainekos et al Temporal logic motion planning for dynamic
robots Automatica 2009Meng Guo Licentiate Seminar 15
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 1 Translation
I Translate ϕ into the Nondeterministic Buchi automaton(NBA) Aϕ over 2AP
Aϕ = (Q 2AP δ Q0 F)
q1
q2
q3
q1q1 nota4
a1 amp nota4
nota4
a2 amp nota4
nota4
a1 amp nota4
a2 amp a3 amp nota4
nota4a1 amp a2 amp a3 amp nota4
a3 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp nota4
a1 amp a2 amp a3 amp nota4
q0
bull Q is a finite set of states
bull 2AP are alphabets
bull δ sube Qtimes 2AP timesQ
bull Q0 F are initial accepting states
bull χ(qm qn) = l isin 2AP | (qm l qn) isin δ
I Automated
I Fast translation algorithm8
8D Oddoux P Gastin LTL2BA software 2009Meng Guo Licentiate Seminar 16
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 2 Product Automaton
I Construct the weighted product automaton Ap = Tc otimesAϕ
Ap = (Qprime δprime Qprime0 F prime Wp)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesFbull δprime sube QtimesQ where (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc
and (qm Lc(πi) qn) isin δ
bull Wp δprime rarr R+ Wp((〈πi qm〉 〈πj qn〉)) = Wc(πi πj)
I Algorithms
bull static construction
bull on-the-fly construction
Meng Guo Licentiate Seminar 17
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Structure and Cost
I Accepting run R of Ap with the prefix-suffix structure
R = Rpre (Rsuf)ω = qprime0 q
prime1 middot middot middot qprimefminus1
[qprimef q
primef+1 middot middot middot qprimen
]ω
I The total cost
Cost(R Ap) =
fminus1sumi=0
Wp(qprimei qprimei+1) + γ
nminus1sumi=f
Wp(qprimei qprimei+1)
Meng Guo Licentiate Seminar 18
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 3 Graph Search
I Algorithm based on Nested-Dijkstra shortest path
bull shortest path from every qprime0 isin Qprime0 to every qprimef isin F prime
bull shortest cycle from qprimef and backP_FFP_IF
I The derived accepting run Ropt with minimal cost
I Corresponding plan τ = Ropt|Π
I Complexity O(|δprime| middot log2 |Qprime| middot (|Qprime0|+ |F prime|))
Meng Guo Licentiate Seminar 19
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Step 4 Hybrid Control Strategy
To execute τ = Ropt|Π using U(x(t) πi πj)
I generate an infinite execution with finite representation
I monitor the execution status
I record past motions
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
Meng Guo Licentiate Seminar 20
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Shortcomings of Nominal Solution
I Reconfiguration
bull plan as sequence of motion (no actions)
bull feasible task
I Real-time adaptation
bull fully-known workspace
bull plan synthesized once off-line
bull executed regardless of the real observation
I Multi-agent system with local tasks
bull independent or dependent tasks
bull communication
bull collaborative tasks
Meng Guo Licentiate Seminar 21
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Shortcomings of Nominal Solution
I Reconfiguration
bull plan as sequence of motion (no actions)
bull feasible task
I Real-time adaptation
bull fully-known workspace
bull plan synthesized once off-line
bull executed regardless of the real observation
I Multi-agent system with local tasks
bull independent or dependent tasks
bull communication
bull collaborative tasks
Meng Guo Licentiate Seminar 21
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 22
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion and Action Planning
Motion Planning
Geometric Constrains
Workspace Model
Model-checking
TaskAction Planning
Discrete Planning
PropositionalLogic
I Why is it necessarybull to automate the choice of actions
bull plan as sequence of motion and actions
I Why plan motion and action togetherbull the purpose of ldquogoing somewhererdquo is to ldquodo somethingrdquo
I Why model motion and action separatelybull robotrsquos mobility depend on the workspace structure
bull robotrsquos capable actions relatively fixed
Meng Guo Licentiate Seminar 23
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Model of Mobility and Action
I Mobility abstraction is given by (similarly as Tc)
M = (ΠM actM minusrarrM ΠM0 ΨM LM WM)
I Capable action set ActB = actB0 actB1 middot middot middot actBKI Precondition function
Cond ActB times 2Ψp times 2Ψs minusrarr TrueFalse
I Effect function
Eff ActB times (2Ψs timesΨb) minusrarr (2Ψs timesΨb)
I Mimic action description language (ADL)
Meng Guo Licentiate Seminar 24
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Model of Complete Functionalities
hellip
|||
M
Bhellip
R
I Complete functionalities by composing M and B
R = (ΠR ActR minusrarrR ΠR0 ΨR LR WR)
I Automated algorithm
Meng Guo Licentiate Seminar 25
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Much richer task specifications
I Given ϕ over robot motion action and internal states
I Accepting run with prefix-suffix structure with similardefinition for cost
I Plan as a sequence of motion and action minimal cost
I Construct the hybrid controller accordingly
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
r1 c1 c2 c3 r3PickG
c3 c2 r2Drop c2 r5PickR
c2 r2Drop c2 c1(r1)ω
Meng Guo Licentiate Seminar 26
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Much richer task specifications
I Given ϕ over robot motion action and internal states
I Accepting run with prefix-suffix structure with similardefinition for cost
I Plan as a sequence of motion and action minimal cost
I Construct the hybrid controller accordingly
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
r1 c1 c2 c3 r3PickG
c3 c2 r2Drop c2 r5PickR
c2 r2Drop c2 c1(r1)ω
Meng Guo Licentiate Seminar 26
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goalbull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Balanced Cost
I Accepting run R with prefix-suffix structure
R = qprime0 qprime1 middot middot middot [ qprimef qprimef+1 middot middot middot qprimen ]ω
= 〈π0 q0〉 〈π1 q1〉 middot middot middot [ 〈πf qf 〉 middot middot middot 〈πn qn〉 ]ω
I The balanced cost of an accepting run
Cost(R Ar) =
fminus1sumi=0
Wr(qprimei qprimei+1) + γ
nminus1sumi=f
Wr(qprimei qprimei+1)
= costτ + α middot distϕ
I costτ implementation cost distϕ distance to ϕ
I distϕ = 0rArr R|Π |= ϕ
Meng Guo Licentiate Seminar 29
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|Π
I Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|ΠI Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Shortcomings of Nominal Solution
I Reconfiguration
bull plan as sequence of motion (no actions)
bull feasible task
I Real-time adaptation
bull fully-known workspace
bull plan synthesized once off-line
bull executed regardless of the real observation
I Multi-agent system with local tasks
bull independent or dependent tasks
bull communication
bull collaborative tasks
Meng Guo Licentiate Seminar 21
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 22
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion and Action Planning
Motion Planning
Geometric Constrains
Workspace Model
Model-checking
TaskAction Planning
Discrete Planning
PropositionalLogic
I Why is it necessarybull to automate the choice of actions
bull plan as sequence of motion and actions
I Why plan motion and action togetherbull the purpose of ldquogoing somewhererdquo is to ldquodo somethingrdquo
I Why model motion and action separatelybull robotrsquos mobility depend on the workspace structure
bull robotrsquos capable actions relatively fixed
Meng Guo Licentiate Seminar 23
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Model of Mobility and Action
I Mobility abstraction is given by (similarly as Tc)
M = (ΠM actM minusrarrM ΠM0 ΨM LM WM)
I Capable action set ActB = actB0 actB1 middot middot middot actBKI Precondition function
Cond ActB times 2Ψp times 2Ψs minusrarr TrueFalse
I Effect function
Eff ActB times (2Ψs timesΨb) minusrarr (2Ψs timesΨb)
I Mimic action description language (ADL)
Meng Guo Licentiate Seminar 24
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Model of Complete Functionalities
hellip
|||
M
Bhellip
R
I Complete functionalities by composing M and B
R = (ΠR ActR minusrarrR ΠR0 ΨR LR WR)
I Automated algorithm
Meng Guo Licentiate Seminar 25
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Much richer task specifications
I Given ϕ over robot motion action and internal states
I Accepting run with prefix-suffix structure with similardefinition for cost
I Plan as a sequence of motion and action minimal cost
I Construct the hybrid controller accordingly
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
r1 c1 c2 c3 r3PickG
c3 c2 r2Drop c2 r5PickR
c2 r2Drop c2 c1(r1)ω
Meng Guo Licentiate Seminar 26
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Much richer task specifications
I Given ϕ over robot motion action and internal states
I Accepting run with prefix-suffix structure with similardefinition for cost
I Plan as a sequence of motion and action minimal cost
I Construct the hybrid controller accordingly
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
r1 c1 c2 c3 r3PickG
c3 c2 r2Drop c2 r5PickR
c2 r2Drop c2 c1(r1)ω
Meng Guo Licentiate Seminar 26
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goalbull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Balanced Cost
I Accepting run R with prefix-suffix structure
R = qprime0 qprime1 middot middot middot [ qprimef qprimef+1 middot middot middot qprimen ]ω
= 〈π0 q0〉 〈π1 q1〉 middot middot middot [ 〈πf qf 〉 middot middot middot 〈πn qn〉 ]ω
I The balanced cost of an accepting run
Cost(R Ar) =
fminus1sumi=0
Wr(qprimei qprimei+1) + γ
nminus1sumi=f
Wr(qprimei qprimei+1)
= costτ + α middot distϕ
I costτ implementation cost distϕ distance to ϕ
I distϕ = 0rArr R|Π |= ϕ
Meng Guo Licentiate Seminar 29
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|Π
I Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|ΠI Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 22
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion and Action Planning
Motion Planning
Geometric Constrains
Workspace Model
Model-checking
TaskAction Planning
Discrete Planning
PropositionalLogic
I Why is it necessarybull to automate the choice of actions
bull plan as sequence of motion and actions
I Why plan motion and action togetherbull the purpose of ldquogoing somewhererdquo is to ldquodo somethingrdquo
I Why model motion and action separatelybull robotrsquos mobility depend on the workspace structure
bull robotrsquos capable actions relatively fixed
Meng Guo Licentiate Seminar 23
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Model of Mobility and Action
I Mobility abstraction is given by (similarly as Tc)
M = (ΠM actM minusrarrM ΠM0 ΨM LM WM)
I Capable action set ActB = actB0 actB1 middot middot middot actBKI Precondition function
Cond ActB times 2Ψp times 2Ψs minusrarr TrueFalse
I Effect function
Eff ActB times (2Ψs timesΨb) minusrarr (2Ψs timesΨb)
I Mimic action description language (ADL)
Meng Guo Licentiate Seminar 24
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Model of Complete Functionalities
hellip
|||
M
Bhellip
R
I Complete functionalities by composing M and B
R = (ΠR ActR minusrarrR ΠR0 ΨR LR WR)
I Automated algorithm
Meng Guo Licentiate Seminar 25
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Much richer task specifications
I Given ϕ over robot motion action and internal states
I Accepting run with prefix-suffix structure with similardefinition for cost
I Plan as a sequence of motion and action minimal cost
I Construct the hybrid controller accordingly
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
r1 c1 c2 c3 r3PickG
c3 c2 r2Drop c2 r5PickR
c2 r2Drop c2 c1(r1)ω
Meng Guo Licentiate Seminar 26
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Much richer task specifications
I Given ϕ over robot motion action and internal states
I Accepting run with prefix-suffix structure with similardefinition for cost
I Plan as a sequence of motion and action minimal cost
I Construct the hybrid controller accordingly
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
r1 c1 c2 c3 r3PickG
c3 c2 r2Drop c2 r5PickR
c2 r2Drop c2 c1(r1)ω
Meng Guo Licentiate Seminar 26
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goalbull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Balanced Cost
I Accepting run R with prefix-suffix structure
R = qprime0 qprime1 middot middot middot [ qprimef qprimef+1 middot middot middot qprimen ]ω
= 〈π0 q0〉 〈π1 q1〉 middot middot middot [ 〈πf qf 〉 middot middot middot 〈πn qn〉 ]ω
I The balanced cost of an accepting run
Cost(R Ar) =
fminus1sumi=0
Wr(qprimei qprimei+1) + γ
nminus1sumi=f
Wr(qprimei qprimei+1)
= costτ + α middot distϕ
I costτ implementation cost distϕ distance to ϕ
I distϕ = 0rArr R|Π |= ϕ
Meng Guo Licentiate Seminar 29
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|Π
I Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|ΠI Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Motion and Action Planning
Motion Planning
Geometric Constrains
Workspace Model
Model-checking
TaskAction Planning
Discrete Planning
PropositionalLogic
I Why is it necessarybull to automate the choice of actions
bull plan as sequence of motion and actions
I Why plan motion and action togetherbull the purpose of ldquogoing somewhererdquo is to ldquodo somethingrdquo
I Why model motion and action separatelybull robotrsquos mobility depend on the workspace structure
bull robotrsquos capable actions relatively fixed
Meng Guo Licentiate Seminar 23
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Model of Mobility and Action
I Mobility abstraction is given by (similarly as Tc)
M = (ΠM actM minusrarrM ΠM0 ΨM LM WM)
I Capable action set ActB = actB0 actB1 middot middot middot actBKI Precondition function
Cond ActB times 2Ψp times 2Ψs minusrarr TrueFalse
I Effect function
Eff ActB times (2Ψs timesΨb) minusrarr (2Ψs timesΨb)
I Mimic action description language (ADL)
Meng Guo Licentiate Seminar 24
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Model of Complete Functionalities
hellip
|||
M
Bhellip
R
I Complete functionalities by composing M and B
R = (ΠR ActR minusrarrR ΠR0 ΨR LR WR)
I Automated algorithm
Meng Guo Licentiate Seminar 25
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Much richer task specifications
I Given ϕ over robot motion action and internal states
I Accepting run with prefix-suffix structure with similardefinition for cost
I Plan as a sequence of motion and action minimal cost
I Construct the hybrid controller accordingly
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
r1 c1 c2 c3 r3PickG
c3 c2 r2Drop c2 r5PickR
c2 r2Drop c2 c1(r1)ω
Meng Guo Licentiate Seminar 26
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Much richer task specifications
I Given ϕ over robot motion action and internal states
I Accepting run with prefix-suffix structure with similardefinition for cost
I Plan as a sequence of motion and action minimal cost
I Construct the hybrid controller accordingly
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
r1 c1 c2 c3 r3PickG
c3 c2 r2Drop c2 r5PickR
c2 r2Drop c2 c1(r1)ω
Meng Guo Licentiate Seminar 26
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goalbull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Balanced Cost
I Accepting run R with prefix-suffix structure
R = qprime0 qprime1 middot middot middot [ qprimef qprimef+1 middot middot middot qprimen ]ω
= 〈π0 q0〉 〈π1 q1〉 middot middot middot [ 〈πf qf 〉 middot middot middot 〈πn qn〉 ]ω
I The balanced cost of an accepting run
Cost(R Ar) =
fminus1sumi=0
Wr(qprimei qprimei+1) + γ
nminus1sumi=f
Wr(qprimei qprimei+1)
= costτ + α middot distϕ
I costτ implementation cost distϕ distance to ϕ
I distϕ = 0rArr R|Π |= ϕ
Meng Guo Licentiate Seminar 29
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|Π
I Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|ΠI Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Model of Mobility and Action
I Mobility abstraction is given by (similarly as Tc)
M = (ΠM actM minusrarrM ΠM0 ΨM LM WM)
I Capable action set ActB = actB0 actB1 middot middot middot actBKI Precondition function
Cond ActB times 2Ψp times 2Ψs minusrarr TrueFalse
I Effect function
Eff ActB times (2Ψs timesΨb) minusrarr (2Ψs timesΨb)
I Mimic action description language (ADL)
Meng Guo Licentiate Seminar 24
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Model of Complete Functionalities
hellip
|||
M
Bhellip
R
I Complete functionalities by composing M and B
R = (ΠR ActR minusrarrR ΠR0 ΨR LR WR)
I Automated algorithm
Meng Guo Licentiate Seminar 25
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Much richer task specifications
I Given ϕ over robot motion action and internal states
I Accepting run with prefix-suffix structure with similardefinition for cost
I Plan as a sequence of motion and action minimal cost
I Construct the hybrid controller accordingly
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
r1 c1 c2 c3 r3PickG
c3 c2 r2Drop c2 r5PickR
c2 r2Drop c2 c1(r1)ω
Meng Guo Licentiate Seminar 26
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Much richer task specifications
I Given ϕ over robot motion action and internal states
I Accepting run with prefix-suffix structure with similardefinition for cost
I Plan as a sequence of motion and action minimal cost
I Construct the hybrid controller accordingly
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
r1 c1 c2 c3 r3PickG
c3 c2 r2Drop c2 r5PickR
c2 r2Drop c2 c1(r1)ω
Meng Guo Licentiate Seminar 26
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goalbull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Balanced Cost
I Accepting run R with prefix-suffix structure
R = qprime0 qprime1 middot middot middot [ qprimef qprimef+1 middot middot middot qprimen ]ω
= 〈π0 q0〉 〈π1 q1〉 middot middot middot [ 〈πf qf 〉 middot middot middot 〈πn qn〉 ]ω
I The balanced cost of an accepting run
Cost(R Ar) =
fminus1sumi=0
Wr(qprimei qprimei+1) + γ
nminus1sumi=f
Wr(qprimei qprimei+1)
= costτ + α middot distϕ
I costτ implementation cost distϕ distance to ϕ
I distϕ = 0rArr R|Π |= ϕ
Meng Guo Licentiate Seminar 29
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|Π
I Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|ΠI Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Model of Complete Functionalities
hellip
|||
M
Bhellip
R
I Complete functionalities by composing M and B
R = (ΠR ActR minusrarrR ΠR0 ΨR LR WR)
I Automated algorithm
Meng Guo Licentiate Seminar 25
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Much richer task specifications
I Given ϕ over robot motion action and internal states
I Accepting run with prefix-suffix structure with similardefinition for cost
I Plan as a sequence of motion and action minimal cost
I Construct the hybrid controller accordingly
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
r1 c1 c2 c3 r3PickG
c3 c2 r2Drop c2 r5PickR
c2 r2Drop c2 c1(r1)ω
Meng Guo Licentiate Seminar 26
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Much richer task specifications
I Given ϕ over robot motion action and internal states
I Accepting run with prefix-suffix structure with similardefinition for cost
I Plan as a sequence of motion and action minimal cost
I Construct the hybrid controller accordingly
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
r1 c1 c2 c3 r3PickG
c3 c2 r2Drop c2 r5PickR
c2 r2Drop c2 c1(r1)ω
Meng Guo Licentiate Seminar 26
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goalbull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Balanced Cost
I Accepting run R with prefix-suffix structure
R = qprime0 qprime1 middot middot middot [ qprimef qprimef+1 middot middot middot qprimen ]ω
= 〈π0 q0〉 〈π1 q1〉 middot middot middot [ 〈πf qf 〉 middot middot middot 〈πn qn〉 ]ω
I The balanced cost of an accepting run
Cost(R Ar) =
fminus1sumi=0
Wr(qprimei qprimei+1) + γ
nminus1sumi=f
Wr(qprimei qprimei+1)
= costτ + α middot distϕ
I costτ implementation cost distϕ distance to ϕ
I distϕ = 0rArr R|Π |= ϕ
Meng Guo Licentiate Seminar 29
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|Π
I Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|ΠI Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Much richer task specifications
I Given ϕ over robot motion action and internal states
I Accepting run with prefix-suffix structure with similardefinition for cost
I Plan as a sequence of motion and action minimal cost
I Construct the hybrid controller accordingly
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
r1 c1 c2 c3 r3PickG
c3 c2 r2Drop c2 r5PickR
c2 r2Drop c2 c1(r1)ω
Meng Guo Licentiate Seminar 26
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Much richer task specifications
I Given ϕ over robot motion action and internal states
I Accepting run with prefix-suffix structure with similardefinition for cost
I Plan as a sequence of motion and action minimal cost
I Construct the hybrid controller accordingly
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
r1 c1 c2 c3 r3PickG
c3 c2 r2Drop c2 r5PickR
c2 r2Drop c2 c1(r1)ω
Meng Guo Licentiate Seminar 26
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goalbull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Balanced Cost
I Accepting run R with prefix-suffix structure
R = qprime0 qprime1 middot middot middot [ qprimef qprimef+1 middot middot middot qprimen ]ω
= 〈π0 q0〉 〈π1 q1〉 middot middot middot [ 〈πf qf 〉 middot middot middot 〈πn qn〉 ]ω
I The balanced cost of an accepting run
Cost(R Ar) =
fminus1sumi=0
Wr(qprimei qprimei+1) + γ
nminus1sumi=f
Wr(qprimei qprimei+1)
= costτ + α middot distϕ
I costτ implementation cost distϕ distance to ϕ
I distϕ = 0rArr R|Π |= ϕ
Meng Guo Licentiate Seminar 29
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|Π
I Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|ΠI Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Much richer task specifications
I Given ϕ over robot motion action and internal states
I Accepting run with prefix-suffix structure with similardefinition for cost
I Plan as a sequence of motion and action minimal cost
I Construct the hybrid controller accordingly
r1 c1 c2 c3 r3
c3 c2 r2 c2 r5
c2 r2 c2 c1(r1)ω
r1 c1 c2 c3 r3PickG
c3 c2 r2Drop c2 r5PickR
c2 r2Drop c2 c1(r1)ω
Meng Guo Licentiate Seminar 26
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goalbull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Balanced Cost
I Accepting run R with prefix-suffix structure
R = qprime0 qprime1 middot middot middot [ qprimef qprimef+1 middot middot middot qprimen ]ω
= 〈π0 q0〉 〈π1 q1〉 middot middot middot [ 〈πf qf 〉 middot middot middot 〈πn qn〉 ]ω
I The balanced cost of an accepting run
Cost(R Ar) =
fminus1sumi=0
Wr(qprimei qprimei+1) + γ
nminus1sumi=f
Wr(qprimei qprimei+1)
= costτ + α middot distϕ
I costτ implementation cost distϕ distance to ϕ
I distϕ = 0rArr R|Π |= ϕ
Meng Guo Licentiate Seminar 29
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|Π
I Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|ΠI Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goalbull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Balanced Cost
I Accepting run R with prefix-suffix structure
R = qprime0 qprime1 middot middot middot [ qprimef qprimef+1 middot middot middot qprimen ]ω
= 〈π0 q0〉 〈π1 q1〉 middot middot middot [ 〈πf qf 〉 middot middot middot 〈πn qn〉 ]ω
I The balanced cost of an accepting run
Cost(R Ar) =
fminus1sumi=0
Wr(qprimei qprimei+1) + γ
nminus1sumi=f
Wr(qprimei qprimei+1)
= costτ + α middot distϕ
I costτ implementation cost distϕ distance to ϕ
I distϕ = 0rArr R|Π |= ϕ
Meng Guo Licentiate Seminar 29
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|Π
I Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|ΠI Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goal
bull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goalbull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Balanced Cost
I Accepting run R with prefix-suffix structure
R = qprime0 qprime1 middot middot middot [ qprimef qprimef+1 middot middot middot qprimen ]ω
= 〈π0 q0〉 〈π1 q1〉 middot middot middot [ 〈πf qf 〉 middot middot middot 〈πn qn〉 ]ω
I The balanced cost of an accepting run
Cost(R Ar) =
fminus1sumi=0
Wr(qprimei qprimei+1) + γ
nminus1sumi=f
Wr(qprimei qprimei+1)
= costτ + α middot distϕ
I costτ implementation cost distϕ distance to ϕ
I distϕ = 0rArr R|Π |= ϕ
Meng Guo Licentiate Seminar 29
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|Π
I Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|ΠI Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Potentially Infeasible Task
I Def 26 ϕ is infeasible for Tc if no accepting run of Ap canbe found
I Closely related to partially-known workspace
I Examplebull ldquogo to the kitchen find an apple and bring it to merdquo
rArr infeasible if no apple
bull ldquokeep an eye on the kids in the living room and bedroomrdquorArr infeasible if not known where the bedroom is
I Nominal solution fails
I Our goalbull synthesize the plan satisfying the task partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 27
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Balanced Cost
I Accepting run R with prefix-suffix structure
R = qprime0 qprime1 middot middot middot [ qprimef qprimef+1 middot middot middot qprimen ]ω
= 〈π0 q0〉 〈π1 q1〉 middot middot middot [ 〈πf qf 〉 middot middot middot 〈πn qn〉 ]ω
I The balanced cost of an accepting run
Cost(R Ar) =
fminus1sumi=0
Wr(qprimei qprimei+1) + γ
nminus1sumi=f
Wr(qprimei qprimei+1)
= costτ + α middot distϕ
I costτ implementation cost distϕ distance to ϕ
I distϕ = 0rArr R|Π |= ϕ
Meng Guo Licentiate Seminar 29
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|Π
I Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|ΠI Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Balanced Cost
I Accepting run R with prefix-suffix structure
R = qprime0 qprime1 middot middot middot [ qprimef qprimef+1 middot middot middot qprimen ]ω
= 〈π0 q0〉 〈π1 q1〉 middot middot middot [ 〈πf qf 〉 middot middot middot 〈πn qn〉 ]ω
I The balanced cost of an accepting run
Cost(R Ar) =
fminus1sumi=0
Wr(qprimei qprimei+1) + γ
nminus1sumi=f
Wr(qprimei qprimei+1)
= costτ + α middot distϕ
I costτ implementation cost distϕ distance to ϕ
I distϕ = 0rArr R|Π |= ϕ
Meng Guo Licentiate Seminar 29
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|Π
I Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|ΠI Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I Relaxed product automaton Ar = TctimesAϕ
Ar = (Qprime 2AP δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime sube Qprime timesQprime (〈πi qm〉 〈πj qn〉) isin δprime iff (πi πj) isinminusrarrc andexist l isin 2AP such that (qm l qn) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)= Wc(πi πj) + α middot Dist(L(πi) χ(qm qn))
I α ge 0 user-defined balance
Meng Guo Licentiate Seminar 28
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Balanced Cost
I Accepting run R with prefix-suffix structure
R = qprime0 qprime1 middot middot middot [ qprimef qprimef+1 middot middot middot qprimen ]ω
= 〈π0 q0〉 〈π1 q1〉 middot middot middot [ 〈πf qf 〉 middot middot middot 〈πn qn〉 ]ω
I The balanced cost of an accepting run
Cost(R Ar) =
fminus1sumi=0
Wr(qprimei qprimei+1) + γ
nminus1sumi=f
Wr(qprimei qprimei+1)
= costτ + α middot distϕ
I costτ implementation cost distϕ distance to ϕ
I distϕ = 0rArr R|Π |= ϕ
Meng Guo Licentiate Seminar 29
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|Π
I Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|ΠI Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Balanced Cost
I Accepting run R with prefix-suffix structure
R = qprime0 qprime1 middot middot middot [ qprimef qprimef+1 middot middot middot qprimen ]ω
= 〈π0 q0〉 〈π1 q1〉 middot middot middot [ 〈πf qf 〉 middot middot middot 〈πn qn〉 ]ω
I The balanced cost of an accepting run
Cost(R Ar) =
fminus1sumi=0
Wr(qprimei qprimei+1) + γ
nminus1sumi=f
Wr(qprimei qprimei+1)
= costτ + α middot distϕ
I costτ implementation cost distϕ distance to ϕ
I distϕ = 0rArr R|Π |= ϕ
Meng Guo Licentiate Seminar 29
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|Π
I Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|ΠI Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|Π
I Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|ΠI Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I The balanced accepting run
Rbal = minR
Cost(R Ar)
I The balanced plan τbal = Rbal|ΠI Proposed algorithms
bull synthesize Rbal given γ and α
bull computes the associated costτ and distϕ for τbal
I Theorem 31 If ϕ is feasible over Tc the balanced plan τbal
satisfies ϕ if α gt α
Meng Guo Licentiate Seminar 30
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Feedback by Tuning αI α tunable balance between costτ and distϕ
bull α uarr rArr distϕ darr rArr satisfy ϕ more
bull α darr rArr costτ darr rArr cheaper
I Example ϕ = diamsa1 andnot(a2 and a3)
π1
π2
π3
a2a3
a1
a2
30
40 20
10Φ
π0 a1qq1
a1
not a2 amp not a3 not a2 amp not a3
q05 5
0 5 10 15 20 25 3030
40
50
60
70
80
90
100
110
120Cost of the Optimal Accepting Path
To
tal C
ost
by
(7)
30 40 50 60 70 80 900
1
2
3
4
5
6
7
8
Implementation Cost
Dis
tan
ce t
o S
pec
ific
atio
n
Potential Motion Plans
Plan1 (0)
Plan2 0
1(
3)
Plan3 0
2(
3)
Meng Guo Licentiate Seminar 31
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goal
bull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Soft and Hard Specification
I Specification with two distinctive parts
ϕ = ϕhard and ϕsoft
I ϕhard for safety or securitybull ldquodo not go to the balconyrdquo ldquoalways alarm if see firerdquo
I ϕsoft for additional achievement (maybe infeasible)bull ldquocollect the toys in all roomsrdquo
I Nominal solution fails
I Our goalbull synthesize the plan satisfies ϕhard completely and ϕsoft
partially
bull user-defined balance on satisfiability and cost of the plan
Meng Guo Licentiate Seminar 32
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
SolutionI Relaxed intersection of Asoft and Ahard as Aϕ by Alg 9
Aϕ = (Q 2AP δ Q0 F)
I Safety-ensured and relaxed product automaton
Ar = TctimesAϕ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠtimesQ Qprime0 = Π0 timesQ0 F prime = ΠtimesF
bull δprime Qprime rarr 2Qprime 〈πj qn〉 isin δprime(〈πi qm〉) iff (πi πj) isinminusrarrc and
qn isin δ(qm Lc(πi))
bull Wr δprime rarr R+ is the weight function
Wr(〈πi qm〉 〈πj qn〉)=Wc(πi πj) + α middot Dist(Lc(πi) χsoft(q2 q2))
Meng Guo Licentiate Seminar 33
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Theorem 33 Assume R is an accepting run of Arτ = R|Π is safe for Tc and ϕ
I Balanced cost of accepting runs
Cost(R Ar) = costτ + α middot distϕsoft
I The safe accepting run
Rsafe = minR
Cost(R Ar)
I The safe plan τsafe = Rsafe|ΠI Similar algorithms to synthesize Rsafe
I Lemma 32 distϕsoft = 0rArr τsafe |= ϕ
Meng Guo Licentiate Seminar 34
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
On-line Planning
Why put planner on-line
I To handle partially-knownworkspace
I Plan may not be executedas expected
I Plan could be improved
I Feed real-time observationback to planner
Meng Guo Licentiate Seminar 35
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Problem Formulation
I The agentrsquos FTS at time t ge 0
T tc = (Π minusrarrtc Π0 AP L
tc W
tc )
I Task specification
ϕ = ϕsoft and ϕhard
I Our goal
bull model the robotrsquos sensing
bull update the system model
bull guarantee the plan is always valid and safe
Meng Guo Licentiate Seminar 36
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution Framework
Meng Guo Licentiate Seminar 37
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Initial Synthesis and System Update
I Step 1 initial synthesis at t = 0
bull τ0 obtained for feasible or infeasible task
bull starts executing τ0
I Step 2 knowledge update at t ge 0
bull sensing information obtained
Senset = ((π S Snot) E Enot)
I Step 2 update T tc based on Senset
Meng Guo Licentiate Seminar 38
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Plan Verification and Revision
I Step 3 validate the current planbull validity lArrrArr invalid transitions
bull safety lArrrArr unsafe transitions
I Step 4 local revision instead of full synthesis
I Low complexity suitable for real-time applications
I Theorem 35 validity and safety of the revised planguaranteed
Meng Guo Licentiate Seminar 39
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Simulation Example
I Nonholonomic ground vehicle
I Potential filed-based navigation controller9
I Surveillance over regions 2 3 4
I Detect walls and obstacles in real-time
1
23
5
6
7
9
10
11
12
8
4
1
2 3
4
9S R Lindemann I I Hussein S M LaValle Real time feedbackcontrol for nonholonomic mobile robots with obstacles CDC 2006
Meng Guo Licentiate Seminar 40
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 41
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependent Local Tasks
I System of N agents i = 1 middot middot middot N
Ti = (Πi minusrarri Πi0 APi Li Wi)
I Locally-assigned LTL specification by ϕi
I ϕi may contain requirements on other agents j 6= i
bull constraints eg ldquodo not be in the same room with agent 1rdquo
bull collaborations eg ldquomove the desk together with agent 1rdquo
I Difficultiesbull the joined execution may not be mutually feasible even
though the individual one is
bull the priority of each agent plays an important role
Meng Guo Licentiate Seminar 42
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Dependency Cluster
I Dependency Agents i and j are called dependent if
Θ3
Θ2
Θ1
Θ4
(1) agent i depends on agent j ifAPϕi
andAPj 6= empty or
(2) agent j depends on agent i ifAPϕj
andAPi 6= empty
I Dependency graph Gd = (V E) V = 1 2 middot middot middot N andE sube V times V is the dependency relation
I Dependency cluster Θ sube V foralli j isin Θ there is a path fromi to j in Gd
Meng Guo Licentiate Seminar 43
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Mutual Infeasible
Within one cluster Θ = 1 2 middot middot middot MI The composed FTS TΘ = T1 times middot middot middot TM is
TΘ = (ΠΘ minusrarrΘ ΠΘ0 APΘ LΘ WΘ)
I The mutual specification is
ϕΘ = ϕ1 and ϕ2 middot middot middot and ϕM
I Mutually infeasible if ϕΘ is infeasible over TΘ
I The relaxed intersection of Aϕi of ϕi i isin Θ
AϕΘ = (Q 2APϕΘ δ Q0 F)
Meng Guo Licentiate Seminar 44
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesF
bull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprimeΘ qb〉) isin δprime iff (πΘ π
primeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Solution
I The relaxed product automaton
ArΘ = TΘ times AϕΘ = (Qprime δprime Qprime0 F prime Wr)
where Qprime = ΠΘ timesQ Qprime0 = ΠΘ0 timesQ0 F prime = ΠΘ timesFbull δprime sube Qprime timesQprime (〈πΘ qa〉 〈πprime
Θ qb〉) isin δprime iff (πΘ πprimeΘ) isinminusrarrΘ
and (qa qb) isin δ
bull Wr δprime rarr R+ is the weight function
Wr(〈πΘ q1 middot middot middot qM t〉 〈πprimeΘ q
prime1 middot middot middot qprimeM tprime〉)
= WΘ(πΘ πprimeΘ) + α
Msumi=1
βi Dist(LΘ(πΘ) χi(qi qprimei))
I α penalty on violating ϕΘ
I βi priority of agent irsquo task
Meng Guo Licentiate Seminar 45
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Synthesize the balanced accepting run of ArΘI Projection onto Ti as the individual plan i isin Θ
I Change α and β
I Example
0 1 2 3 4 5 6 7 8 9 100
2
4
6
8
10
12
14
16
18
20
2 (
1=1)
Unique Optimal Accepting Paths
0 05 1 15 2 25 3 35 4 45 50
05
1
15
2
25
3
35
4
6
Distance to 1
Potential Motion Plans
10
2028
24
36
Dis
tan
ce t
o
2
Meng Guo Licentiate Seminar 46
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Independent Local Tasks
I System of N agents coexisting within a partially-knownworkspace
T ti = (Πi minusrarrti Πi0 APi L
ti W
ti )
I Locally-assigned task specification and independent
ϕi = ϕsofti and ϕhard
i
I Motivation
bull agents located at various locations within the workspace
bull observe up-to-date information
bull beneficial to communicate
Meng Guo Licentiate Seminar 47
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Knowledge Update and Transfer
I Knowledge update bybull own sensing ability Sensetk = (π S Snot) E Enotbull communication with others
I Communication network Nk isin N (static or dynamic)
I Transfer knowledge
bull request once Requesttkg = (k ϕk|APk)
bull event-based reply Replythk = (π Sprime Sprimenot) where
Sprime = S cap (ϕh|APh) and Sprime
not = Snot cap (ϕh|APh)
I Update T tk based on Sensetk and Replytgk
I Validate and revise the current plan
Meng Guo Licentiate Seminar 48
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Results
I Full synthesis or local revision
I Event-based trigger to re-synthesize the plan
0 20 40 60 80 100Time (s)
0
1000
2000
3000
4000
5000
6000
Tota
l Cos
t
[5522]
[3319]
[3132]
[139]
[139]
[5522]
[3319]
[1134]
[341]
[241]
[139]
[7512]
[0318]
[3130]
[139]
[6520]
[0227]
[0135]
[139]
[8520]
[2133]
[240]
[139]
Ar_1Ar_2Ar_3Ar_4Ar_5
0 10 20 30 40 50 60Time
0
2
4
6
8
10
12
14
o
f Mes
sage
s
Ar_1Ar_2Ar_3Ar_4Ar_5
Gw_1Gw_2Gw_3Gw_4Gw_5
Gf_1Gf_2Gf_3Gf_4Gf_5
Meng Guo Licentiate Seminar 49
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Software ImplementationI Robot operating system(ROS)-based
I ROS core + ROS nodes
I ROS node for planning
Meng Guo Licentiate Seminar 50
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Experiments
I NAO humanoid
I MAS Lab CVAP
I NEXUS ground vehicle
I Smart Mobility Lab ACL
Meng Guo Licentiate Seminar 51
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
IntroductionMotivationBackground
Nominal ScenarioProblem FormulationNominal Solution
Reconfiguration
Motion and ActionPotentially Infeasible TaskPartially-known Workspace
Multi-agentDependent Local TasksIndependent Local Tasks
SummarySummary
Meng Guo Licentiate Seminar 52
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Summary
I Motion and task planningbull Discrete motion and task plan with minimal costbull Hybrid control strategy
I Reconfiguration and real-time adaptationbull Potentially infeasible taskbull Soft and hard specificationsbull Partially-known workspacebull Motion and action planning
I Multi-agent systems with local tasksbull Dependent tasksbull Independent tasksbull Software implementation
Meng Guo Licentiate Seminar 53
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Future Work
I Automated abstraction
I Natural language to LTL graphic interface
I Trade-off between computational complexity andoptimality
I Robustness and fault tolerance (both motion and action)
I Continuous constraints coupled dynamics
Meng Guo Licentiate Seminar 54
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-
Introduction Nominal Scenario Reconfiguration Multi-agent Summary
Thank you
Meng Guo Licentiate Seminar 55
- Introduction
-
- Motivation
- Background
-
- Nominal Scenario
-
- Problem Formulation
- Nominal Solution
-
- Reconfiguration
-
- Motion and Action
- Potentially Infeasible Task
- Partially-known Workspace
-
- Multi-agent
-
- Dependent Local Tasks
- Independent Local Tasks
-
- Summary
-
- Summary
-