© rolf pfeifer visiontrain thematic school morphological computation connecting brain, body and...
TRANSCRIPT
© Rolf Pfeifer
VISIONTRAIN Thematic School
Morphological computationConnecting brain, body and environment
Les Houches, 9-14 March 2008
Rolf PfeiferArtificial Intelligence Laboratory, Department of Informatics
University of Zurich, Switzerland
© Rolf Pfeifer
Contents Lecture 2
• real worlds and virtual worlds• properties of complete agents• the quadruped „Puppy“ as a complex dynamical
system• illustration of selected design principles• summary
© Rolf Pfeifer
Contents Lecture 2
• real worlds and virtual worlds• properties of complete agents• the quadruped „Puppy“ as a complex dynamical
system• illustration of selected design principles• summary
© Rolf Pfeifer
Real worlds and virtual worlds
• information acquisition takes time• limited information• noise• no clearly defined states• agents must do several things• own dynamics, time pressure• limited predictability, non-linear, sensitivity to
initial conditions
bounded rationality
© Rolf Pfeifer
Contents Lecture 2
• real worlds and virtual worlds• properties of complete agents• the quadruped „Puppy“ as a complex dynamical
system• illustration of selected design principles• summary
© Rolf Pfeifer
Properties of complete agents
• subject to the laws of physics• generation sensory stimulation• affect the environment through behavior• complex dynamical systems• perform morphological computation
© Rolf Pfeifer
Contents Lecture 2
• real worlds and virtual worlds• properties of complete agents• the quadruped „Puppy“ as a complex dynamical
system• illustration of selected design principles• summary
© Rolf Pfeifer
Rapid locomotionthe quadruped “Puppy”
Design and construction:Fumiya Iida
rapid locomotionin biological systems
© Rolf Pfeifer
The quadruped “Puppy”: summary
• simple control (!)• no sensors• spring-like material properties• self-stabilization
Design and construction:Fumiya Iida
© Rolf Pfeifer
The quadruped “Puppy”: summary
• simple control (!)• no sensors• spring-like material properties• self-stabilization
Design and construction:Fumiya Iida
principle of “cheap design”
© Rolf Pfeifer
The “mini dog” by Fumiya Iida
Artificial Intelligence LaboratoryDept. of Information TechnologyUniversity of Zurich
© Rolf Pfeifer
The quadruped “Puppy”: summary
• simple control (!)• no sensors• spring-like material properties• self-stabilization
Design and construction:Fumiya Iida
© Rolf Pfeifer
Self-stabilization
• “computation” performed by physical dynamics of agent basin of attraction
• stabilization through mechanical feedback• “intra-attractor dynamics” (Kuniyoshi)
© Rolf Pfeifer
Implications of embodiment – self-stabilization
Pfeifer et al., Science,16 Nov. 2007)
“Puppy”
© Rolf Pfeifer
LH
LF
RF
RH
100 200 300 400 500 600 700 800 9000 t (ms)1000 1100 1200 1300
LH
LF
RF
RH
100 ms
LH
LF
RF
RH
1400
gait patterns
Fast gallop
Moderatewalking
Fast runningtrot
© Rolf Pfeifer
Gait patterns as attractor states
Illustration by Shun Iwasawa
induced through interactionwith environment
© Rolf Pfeifer
Morphological computation
Figure 4.1Morphological computation. (a) Sprawl robot exploiting the material properties of its legs for rapid locomotion. The elasticity in the linear joint provided by the air pressure system allows for automatic adaptivity of locomotion over uneven ground, thus reducing the need for computation. (b) An animal exploiting the material properties of its legs (the elasticity of its muscle-tendon system) thus also reducing computation. (c) A robot built from stiff materials must apply complex control to adjust to uneven ground and will therefore be very slow.
© Rolf Pfeifer
Fore legs: iiii BtAP 111 )sin(
Hind legs: iiiii BtAP 222 )sin(
(Iida, Gomez and Pfeifer, 2005)
Gait 1
Gait 0
Gait patterns for grounding a body image
© Rolf Pfeifer
Contents Lecture 2
• real worlds and virtual worlds• properties of complete agents• the quadruped „Puppy“ as a complex dynamical
system• illustration of selected design principles• summary
© Rolf Pfeifer
Agent design principles
Name Description
Three constituents Ecological niche (environment), tasks and agent must always be taken into account
Complete agents Complete agent must be taken into account, not only isolated components
Parallel, loosely coupled processes
Parallel, asynchronous, partly autonomous processes, largely coupled through interaction with environment
Sensory-motor coordination
Behavior sensory-motor coordinated with respect to target, self-generated sensory stimulation
Cheap design Exploitation of niche and interaction; parsimony
Redundancy Partial overlap of functionality based on different physical processes
Ecological balance Balance in complexity of sensory, motor, and neural systems; task dsitribution between morphology, materials, control, and interaction with environment
Value Driving forces: developmental mechanisms; self-organization
© Rolf Pfeifer
The Three-Constituents Principle
• ecological niche• desired behaviors and tasks• design of agent itself
scaffolding
© Rolf Pfeifer
Complete Agent Principle
When designing an agent, always thank about complete agent behaving in real world.
© Rolf Pfeifer
Regonizing andobject in acluttered environment
illustration byShun Iwasawa
manipulation of environment facilitates
perception
robot experimentsby Giorgio Metta
© Rolf Pfeifer
Regonizing andobject in acluttered environment
illustration byShun Iwasawa
manipulation of environment facilitates
perception
complete agent principle
principle ofinformation self-strcuturing
© Rolf Pfeifer
Principle of “cheap design”
Exploitation of
- ecological niche
- characteristics of interaction with environment
design easier: “cheap”
Example:• Lecture 1: “Swiss robots”
© Rolf Pfeifer
Humanlocomotion
Qrio (Sony) Asimo (Honda)
Denise(Delft)
Passive Dynamic Walker(Cornell)
CornellMITDelft
© Rolf Pfeifer
“Passive Dynamic Walker” – the brainless robot (1)
walking without controlDesign and construction:Ruina/Wisse/Collins, Cornell University
Morphology:- shape of feet- counterswing
of arms- friction on
bottom of feet
© Rolf Pfeifer
“Passive Dynamic Walker” – the brainless robot (2)
walking without control
Morphology:- shape of feet- counterswing
of arms- friction on
bottom of feet
Design and construction:Ruina/Wisse/Collins, Cornell University
self-stabilization
principle of “cheap design”
© Rolf Pfeifer
Implications of embodiment – self-stabilization
Pfeifer et al., Science,16 Nov. 2007)
passive dynamic walker
© Rolf Pfeifer
Extending the “Passive Dynamic Walker” – the almost brainless robot
Design and construction:Ruina/Wisse/Collins, Cornell University
Collins, Ruina,Tedrake
“Denise”Martijn Wisse
Morphology:- shape of feet- counterswing
of arms- friction on
bottom of feet
© Rolf Pfeifer
Extending the “Passive Dynamic Walker” – the almost brainless robot
walking with little controlDesign and construction:Martijn Wisse, Delft University
Morphology:- wide feet- counterswing of arms- friction on bottom of feet- high energy efficiency
self-stabilization
© Rolf Pfeifer
Pneuman: passive dynamic walker(with pneumatic actuators and torso)
design andconstruction:Koh Hosoda, OsakaUniversity
only hip-joint actuatedothers: passive but pre-pressured (closed valves)
self-stabilization
© Rolf Pfeifer
Implications of embodiment – self-stabilization
(Pfeifer et al., Science,16 Nov. 2007)
Denise (Wisse)Pneuman (Hosoda)
© Rolf Pfeifer
Famous robots:Asimo, Qrio, H-7, HOAP-2, HRP-2
H-7 (Univ. of Tokyo)
HRP-2 (Kawada) Qrio (Sony)
HOAP-2 (Fujitsu)
Asimo (Honda)
© Rolf Pfeifer
Famous robots:Asimo, Qrio, H-7, HOAP-2, HRP-2
H-7 (Univ. of Tokyo)
HRP-2 (Kawada) Qrio (Sony)
HOAP-2 (Fujitsu)
Asimo (Honda)
© Rolf Pfeifer
Famous robots:Asimo, Qrio, H-7, HOAP-2, HRP-2
H-7 (Univ. of Tokyo)
HRP-2 (Kawada) Qrio (Sony)
HOAP-2 (Fujitsu)
Asimo (Honda)
no exploitation of dynamics, morphology,and materials
© Rolf Pfeifer
Biped walking:Exploiting interaction with environment
• leg as pendulum• control for free• energy efficiency• self-stabilization
principle of “cheap design”
© Rolf Pfeifer
Case study on morphology and materials: “Stumpy”
Design and construction: Raja Dravid, Fumiya Iida, Max Lungarella, Chandana Paul
actuated joints
almost brainless (very simple control)two motors
elastic materials
surface properties
© Rolf Pfeifer
“Cheap” behavioral diversity: “Stumpy”
Design and construction: Raja Dravid, Fumiya Iida, Max Lungarella, Chandana Paul
© Rolf Pfeifer
“Stumpy”: Summary
• Exploitation of dynamics– natural stiffness and elasticity of the materials– surface properties of the feet
• many behaviors with only two joints• self-stabilization• good control through exploitation of morphology and
materials little control required
principle of “cheap design”
© Rolf Pfeifer
Implications of embodiment – self-stabilization
(Pfeifer et al., Science,16 Nov. 2007)
Denise (Wisse)Pneuman (Hosoda)Stumpy (Dravid/Iida)
© Rolf Pfeifer
Insect walking
Holk Cruse• no central controller for leg-
coordination• only local communication
neuronalconnections
© Rolf Pfeifer
Insect walking
Holk Cruse• no central controller for leg-
coordination• only local communication
neuronalconnections
© Rolf Pfeifer
Insect walking
Holk Cruse• no central controller for leg-
coordination• only local communication• global communication
through interaction with environment
neuronalconnections
© Rolf Pfeifer
Global communication through interaction with environment
angle sensorsin joints
exploitation of interaction with environmentsimpler neuronal circuits
“cheap design”
“parallel, loosely coupled processes”
© Rolf Pfeifer
The principle of “parallel, loosely coupled processes”
Intelligent behavior:• emergent from agent-environment interaction• based on large number of parallel, loosely
coupled processes• asynchronous• coupled through agent’s sensory-motor system
and environment
© Rolf Pfeifer
Artificial Fish “Wanda”: Exploiting morphology and system-environment interaction
1 DOF actuation (DOF=Degree Of Freedom)
controlling:- up-down- left-right- speed- reaching any point
in x, y, z-space
Design and construction:Horishi Yokoi
Fumiya IidaMark Ziegler
© Rolf Pfeifer
Design and construction:Horishi YokoiFumiya IidaMark Ziegler
Artificial Fish “Wanda”: Exploiting morphology and system-environment interaction
“cheap design”
© Rolf PfeiferDesign and construction:
Mark Ziegler
Artificial Fish “Findus”: Exploiting morphology and materials
“cheap design”
© Rolf Pfeifer
Kismet - the social interaction robot
Cynthia Breazeal, MIT Media Lab(previously MIT AI Lab)
Kismet
43D.MOV
© Rolf Pfeifer
Kismet - the social interaction robot
Cynthia Breazeal, MIT Media Lab(previously MIT AI Lab)
Kismet
Reflexes:- turn towards loud noise- turn towards moving objects- follow slowly moving objects- habituation
© Rolf Pfeifer
Kismet - the social interaction robot
Cynthia Breazeal, MIT Media Lab(previously MIT AI Lab)
Kismet
Reflexes:- turn towards loud noise- turn towards moving objects- follow slowly moving objects- habituation
“principle of parallel, looselycoupled processes”
© Rolf Pfeifer
Kismet - the social interaction robot
Cynthia Breazeal, MIT Media Lab(previously MIT AI Lab)
Kismet
Reflexes:- turn towards loud noise- turn towards moving objects- follow slowly moving objects- habituation
“principle of parallel, looselycoupled processes”
social competence as a collection of reflexes ?!??
© Rolf Pfeifer
Principle of “ecological balance”
balance in complexity• given task environment• match in complexity of sensory, motor, and
neural system
balance / task distribution between• morphology• neuronal processing (nervous system)• materials• environment
© Rolf Pfeifer
Principle of “ecological balance”
balance in complexity• given task environment• match in complexity of sensory, motor, and
neural system
balance / task distribution between• morphology• neuronal processing (nervous system)• materials• environment
© Rolf Pfeifer
Braitenberg Vehicle 1 with large brain
ecologically unbalanced system
sensor for one quality(e.g. temperature, light)
one motor
very large brain
© Rolf Pfeifer
Principle of “ecological balance”
balance in complexity• given task environment• match in complexity of sensory, motor, and
neural system
balance / task distribution between• morphology• neuronal processing (nervous system)• materials• environment
© Rolf Pfeifer
Examples
• arm turning• loosely swinging arm• “Passive dynamic walker”• “Puppy”• “Stumpy”• cockroaches climbing over obstacles
© Rolf Pfeifer
“Morphological computation” in cockroaches
(pictures and moviescourtesy Roy Ritzmann,Case Western Reserve Univ.)
© Rolf Pfeifer
“Morphological computation” in cockroaches
(pictures and moviescourtesy Roy Ritzmann,Case Western Reserve Univ.)
© Rolf Pfeifer
Self-regulating properties of coackroach body
brain: 1 Mio. neurons(rough estimate)
descending cells: 200 (!)
brain: - cooperation with local circuits- morphological changes (shoulder joint)
Watson, Ritzmann, Zill & Pollack, 2002, J Comp Physiol A
© Rolf Pfeifer
Changing “morphology”
Watson, Ritzmann, Zill & Pollack, 2002, J Comp Physiol A
shoulder jointconfiguration
brain:1 mio neurons
(unknown)
200 descendingneurons (!)
© Rolf Pfeifer
The redundancy principle
• redundancy prerequisite for adaptive behavior• partial overlap of functionality in different
subsystems• sensory systems: different physical processes
with “information overlap”
© Rolf Pfeifer
The redundancy principle
• redundancy prerequisite for adaptive behavior• partial overlap of functionality in different
subsystems• sensory systems: different physical processes
with “information overlap”
complementary to “cheap design”
© Rolf Pfeifer
Examples of redundancy principle
• different navigation systems of ants• hands for grasping/locomotion• legs/feet for manipulation• breaking systems in airplanes
© Rolf Pfeifer
The redundancy principle
• redundancy prerequisite for adaptive behavior• partial overlap of functionality in different
subsystems• sensory systems: different physical processes
with “information overlap”
complementary to “cheap design”
© Rolf Pfeifer
Contents Lecture 2
• real worlds and virtual worlds• properties of complete agents• the quadruped „Puppy“ as a complex dynamical
system• illustration of selected design principles• summary
© Rolf Pfeifer
Summary Lecture 2
• intrinsic uncertainty in real world• properties of complete agents/dynamical systems• „cheap design“, self-stabilization / redundancy• parallel, loosely coupled processes• ecological balance
© Rolf Pfeifer
Agent design principles
Name Description
Three constituents Ecological niche (environment), tasks and agent must always be taken into account
Complete agents Complete agent must be taken into account, not only isolated components
Parallel, loosely coupled processes
Parallel, asynchronous, partly autonomous processes, largely coupled through interaction with environment
Sensory-motor coordination
Behavior sensory-motor coordinated with respect to target, self-generated sensory stimulation
Cheap design Exploitation of niche and interaction; parsimony
Redundancy Partial overlap of functionality based on different physical processes
Ecological balance Balance in complexity of sensory, motor, and neural systems; task dsitribution between morphology, materials, control, and interaction with environment
Value Driving forces: developmental mechanisms; self-organization