the underwater systems program at the porto university

The Underwater Systems The Underwater Systems Program at the Porto UniversityProgram at the Porto University

Nuno Alexandre CruzNuno Alexandre Cruz

FEUP-DEECFEUP-DEECRua Dr. Roberto FriasRua Dr. Roberto Frias

4200-465 Porto, Portugal4200-465 Porto, Portugalhttp://www.fe.up.pt/~nacruzhttp://www.fe.up.pt/~nacruz

Laboratório de Sistemas e Tecnologia SubaquáticaFaculdade de Engenharia da Universidade do Portohttp://www.fe.up.pt/~lsts

2SUMARE Workshop, Villefranche-sur-Mer, 15-16 October 2003

OutlineOutline

The Underwater Systems and Technology LaboratoryThe Underwater Systems and Technology Laboratory

VehiclesVehicles

– Autonomous underwater vehiclesAutonomous underwater vehicles

– Remotely operated vehicleRemotely operated vehicle

Systems and technologySystems and technology

– Embedded computer systemsEmbedded computer systems

– Navigation systemsNavigation systems

Advanced mission conceptsAdvanced mission concepts

ConclusionConclusion


The Underwater Systems The Underwater Systems and Technology Laboratoryand Technology Laboratory

MissionMissionDesign innovative solutions for Design innovative solutions for

oceanographic and oceanographic and environmental applicationsenvironmental applications

PeoplePeople4 Faculty staff4 Faculty staff

10 researchers10 researchers

VehiclesVehiclesAutonomous submarines Autonomous submarines

Remotely operated submarineRemotely operated submarine

TechnologiesTechnologiesNavigation and controlNavigation and control

Acoustic networksAcoustic networks

Networked control systemsNetworked control systems

Power/computer systemsPower/computer systems

ApplicationsApplicationsMonitoring sea outfallsMonitoring sea outfalls

Coastal oceanographyCoastal oceanography

Underwater archaeologyUnderwater archaeology

Inspection and interventionInspection and intervention

SUMARE Workshop, Villefranche-sur-Mer, 15-16 October 2003 Artwork Courtesy of Michael Incze, NUWC


CooperationCooperation

NationalNational

Administração dos Administração dos Portos do Douro e Portos do Douro e LeixõesLeixões

Centro de Centro de Investigação Investigação Marinha e AmbientalMarinha e Ambiental

Instituto Superior de Instituto Superior de Engenharia do PortoEngenharia do Porto

Instituto Instituto HidrográficoHidrográfico

InternationalInternational

University of University of California at California at Berkeley, CA, USABerkeley, CA, USA

Woods Hole Woods Hole Oceanographic Oceanographic Institution, MA, USAInstitution, MA, USA

Naval Postgraduate Naval Postgraduate School, CA, USASchool, CA, USA

VehiclesVehicles

Autonomous Underwater VehiclesAutonomous Underwater Vehicles


IsurusIsurus AUV (1997) AUV (1997) REMUS class AUV (WHOI)REMUS class AUV (WHOI) Length: 1.8mLength: 1.8m Diameter: 20 cmDiameter: 20 cm Weight in air: 35 kgWeight in air: 35 kg Max speed: 2 m/sMax speed: 2 m/s Max range: 100 kmMax range: 100 km Payload sensorsPayload sensors

– Sidescan SonarSidescan Sonar– CTDCTD– Echo sounderEcho sounder– Optical backscatterOptical backscatter– (Video camera)(Video camera)– ……


Computational systemComputational system

On-board softwareOn-board software

Mission programmingMission programming

Integrated navigation systemIntegrated navigation system

Power supply and power managementPower supply and power management

Actuation systemActuation system

Customization at LSTSCustomization at LSTS


Operating the Operating the IsurusIsurus AUV AUV

Mission Support SystemMission Support SystemSmall boatSmall boat

LaptopLaptop

Acoustic navigation networkAcoustic navigation network

Operational ProceduresAcoustic network setup

Mission programming

Vehicle launching

...

Vehicle recovery

Data download and processing


New Generation AUV New Generation AUV (2003) (2003)

Main featuresMain featuresLow costLow cost

Carbon fiber hullCarbon fiber hull

Modular sensor adaptersModular sensor adapters

Payload: 8 kgPayload: 8 kg

Depth rating: 150 mDepth rating: 150 m

Autonomy: 20 hours +Autonomy: 20 hours +

2 vert. & 2 horiz. fins2 vert. & 2 horiz. fins

1 propeller1 propeller

IsurusIsurus Missions Missions

BathymetryBathymetry

Oceanographic data collectionOceanographic data collection

Environmental monitoringEnvironmental monitoring


Estuary of Minho River Estuary of Minho River (1998+)(1998+)

Mission ProfileMission Profile• NW-SE cross sections, 50 m apartNW-SE cross sections, 50 m apart• Section length: 700-1200 mSection length: 700-1200 m• Tracks repeated for various depthsTracks repeated for various depths• Data collected:Data collected:

• Temperature and Salinity (CTD)Temperature and Salinity (CTD)• Bathymetry (CTD & Echosounder)Bathymetry (CTD & Echosounder)

• Width: 1-2 kmWidth: 1-2 km• Depth: 2-5 mDepth: 2-5 m

• Currents: over 1m/sCurrents: over 1m/s


Estuary of Minho River – Estuary of Minho River – ResultsResults

BathymetryD

ep

th (

m)

North (m) East (m)


Estuary of Minho River – Estuary of Minho River – Results Results

Temperature and Salinity (@1m depth)

Nor

th (

m)

Nor

th (

m)

East (m) East (m)


Tapada Do Outeiro (2000+)Tapada Do Outeiro (2000+)

Mission ObjectivesMission Objectives– Study the impact of Study the impact of

discharges from discharges from thermoelectric power thermoelectric power plantplant

– Assess the erosion of the Assess the erosion of the river bedriver bed

Mission DataMission Data– TemperatureTemperature

– Bathymetry profilesBathymetry profiles


Mission ObjectivesMission Objectives– Evaluation of Evaluation of

environmental impact of environmental impact of sewage outfallsewage outfall

– Find and map the plumeFind and map the plume

Mission ScenarioMission Scenario– Open seaOpen sea

– 2 km off the coast of 2 km off the coast of AveiroAveiro

– 20 m of depth20 m of depth

Aveiro Sea Outfall (2002+)Aveiro Sea Outfall (2002+)


Mission PlanningMission Planning– Reference data collectionReference data collection

– Simulation of plume behaviorSimulation of plume behavior

– Delimitation of mission areaDelimitation of mission area

– Mission programmingMission programming

Mission DataMission Data– TemperatureTemperature

– SalinitySalinity

– Optical BackscatterOptical Backscatter

Aveiro Sea Outfall – Aveiro Sea Outfall – Planning Planning


Aveiro Sea Outfall - Aveiro Sea Outfall - OperationsOperations


2

4

10

2 4 10

Temperature and SalinityTemperature and Salinity

Aveiro Sea Outfall - ResultsAveiro Sea Outfall - Results


Aveiro Sea Outfall – Aveiro Sea Outfall – LessonsLessons Launching an AUV at open sea is hardLaunching an AUV at open sea is hard

Recovering an AUV from open sea is VERY hardRecovering an AUV from open sea is VERY hard

MurphyMurphy is ALWAYS watching is ALWAYS watching

Safety measures are never too manySafety measures are never too many

MissionDuration

Wave Height at Leixões2002-07-26 to 2002-08-02

VehiclesVehicles

Remotely Operated VehicleRemotely Operated Vehicle


The IES Project (1999-The IES Project (1999-2002)2002) ObjectivesObjectives

– Develop an automated system for the inspection Develop an automated system for the inspection of underwater structuresof underwater structures

– Provide non-trained operators with autonomous Provide non-trained operators with autonomous and semi-autonomous operation modesand semi-autonomous operation modes

StrategyStrategy– Acquire a customized version of a commercial Acquire a customized version of a commercial

ROVROV– Integrate on-board computational system Integrate on-board computational system – Install navigation and inspection sensorsInstall navigation and inspection sensors– Implement a set of automated maneuversImplement a set of automated maneuvers


Original ROV (2000)Original ROV (2000)

Customized VehicleCustomized Vehicle– Phantom 500 S (Deep Phantom 500 S (Deep

Ocean Engineering)Ocean Engineering)

– Electronics compartmentElectronics compartment

– Enlarged frameEnlarged frame

– Increased flotationIncreased flotation

– Extra motor powerExtra motor power

(4 * 1/8 hp)(4 * 1/8 hp)


Doppler

NavigationSensors

Console

IMU

ComputationalSystem

InterfaceDevices

Compass Inclination

Acoustics

Depth Thrusters Lights Pan & TiltVideo Sonar Picture

InspectionSensors

Actuators

ROV

Umbilical

PowerManagement

ROV Hardware ProjectROV Hardware Project


ROV Hardware ROV Hardware DevelopmentDevelopment

Main containerMain container– Computational systemComputational system

– Navigation systemNavigation system

– Interface devicesInterface devices

– Power distributionPower distribution

Small containersSmall containers– Power distributionPower distribution

– Power managementPower management

– Motor controlMotor control

– Interface devicesInterface devices


Current ROV ConfigurationCurrent ROV Configuration Inspection systemInspection system

– Camera: Camera: InspectorInspector (ROS) (ROS)– Pan and Tilt unit (Imenco)Pan and Tilt unit (Imenco)– Lights: up to 600W (DSP&L)Lights: up to 600W (DSP&L)– Forward looking sonar (Imagenex)Forward looking sonar (Imagenex)

NavigationNavigation– DVL: DVL: ArgonautArgonaut (Sontek) (Sontek)– IMU: IMU: HG1700HG1700 (Honeywell) (Honeywell)– Digital Compass: Digital Compass: TCM2TCM2 (PNI) (PNI)– Depth sensor, 730+ (PSI)Depth sensor, 730+ (PSI)– Acoustic Tx/Rx: 20-30 KHzAcoustic Tx/Rx: 20-30 KHz

Computational systemComputational system– PC/104 stack, PC/104 stack, PentiumPentium PC PC– QNXQNX RTOS RTOS– EthernetEthernet

Power supplyJunction boxUmbilicalWinchSpare kit


ROV Modes of OperationROV Modes of Operation

Modes of operation

1. Teleoperation:Direct commands using a joystick

2. Teleprogramming:Pre-programmed maneuvers

Real-time Real-time videovideo

SonarSonarDataData EnvironmentEnvironment

MapMapInternalInternal State State

ControlsControls

MotionMotionPlanPlan

Maneuver Maneuver ParametersParameters


ROV Operations at APDLROV Operations at APDL

Objectives– Detect corrosion in steel plates protecting walls– Register video footage with localization data– Tag features for diver intervention or latter reinspection

Inspected Structures


ROV Operations at APDLROV Operations at APDL

Main Difficulties– Reduced visibility (<0.5m)– Boundary perturbations– Cable dynamics

Solutions– High sensitivity camera– Variable illumination– Multiple sensor fusion for

navigation and control– Navigation info at the

console

Systems and TechnologiesSystems and Technologies


Embedded Computational Embedded Computational SystemsSystems

Based on PC/104 technologyBased on PC/104 technology– Small form-factorSmall form-factor– Plenty of COTS vendors and Plenty of COTS vendors and

solutionssolutions– Low-cost boardsLow-cost boards

Software applications and Software applications and drivers developed for RTOSdrivers developed for RTOS

Several systems in operationSeveral systems in operation– Underwater vehicles (AUV/ROV)Underwater vehicles (AUV/ROV)– Automated trucks and bussesAutomated trucks and busses


Navigation SystemsNavigation Systems Internal devices

– Digital compasses

– Doppler velocimeters

– Inertial systems

– Pressure sensors (depth)

– Acoustic Tx/Rx boards

Algorithms– LBL navigation

– Sensor fusion (Kalman filter)

– Post-mission trajectory smoothing

– External tracking

Navigation networks– Acoustic beacons

– Surface buoys

d2d1

baseline

(not to scale)


Vehicle NavigationVehicle Navigation

Kalman filter based algorithmKalman filter based algorithm– Filter state: horizontal position and water currentFilter state: horizontal position and water current

– High rate dead-reckoning dataHigh rate dead-reckoning data

– Low rate range measurementsLow rate range measurements

Real-time transponder selectionReal-time transponder selection– Covariance matrix updated in real timeCovariance matrix updated in real time

– Interrogation sequence driven by innovation Interrogation sequence driven by innovation potentialpotential


Post Mission Trajectory Post Mission Trajectory SmoothingSmoothing

6050 6100 6150 6200 6250 63000

0.5

1

1.5

2

2.5

3

3.5

time (s)

uncert

ain

ty (

m)

smoothedreal-time

55 60 65 70 75 80 85 90 95 100 105 110 115

-80

-75

-70

-65

-60

-55

-50

-45

-40

-35

east (m)

nort

h (m

)

smoothedreal-time

Algorithm based on Algorithm based on the the Rauch-Tung-Striebel Rauch-Tung-Striebel nonlinear smoothernonlinear smoother

State similar to the State similar to the online filteronline filter

Estimates depend on Estimates depend on past and “future” datapast and “future” data

Uses data recorded on Uses data recorded on the on-board computerthe on-board computer

Trajectorydetail

Uncertainty


Passive Tracking AlgorithmPassive Tracking Algorithm

vehicle pings txponder #1

txponder detects &

replies

vehicle detects & pings

txponder #2

t1 t1

t2 t3

t1 t4

t2

t4

t3 t2

txponder detects &

replies

vehicle detects & pings

txponder #1

txponder detects &

replies

time

time

2* t1 + t2 + t3 2* t4 + t2 + t3

ping #1 detected

ping #2 detected

ping #1 detected


External Tracking External Tracking MechanismMechanism Normal operationNormal operation

– Listenning device just detects pings sent by the vehiclesListenning device just detects pings sent by the vehicles– After two interrogations, a range is computedAfter two interrogations, a range is computed– Listenning device can be located anywhere within acoustic Listenning device can be located anywhere within acoustic

range (including other AUVs!)range (including other AUVs!)– Vehicles keep navigating at the end of missionVehicles keep navigating at the end of mission

Emergency operationEmergency operation– Simple commands can be sent to the vehiclesSimple commands can be sent to the vehicles– Vehicles carry an automatic responderVehicles carry an automatic responder– Ranges can be estimated even with computer system shut Ranges can be estimated even with computer system shut

downdown


Interface to the navigation beaconsInterface to the navigation beacons– display of acoustic signals being transmitted and receiveddisplay of acoustic signals being transmitted and received

– map the position of the surface buoys (GPS)map the position of the surface buoys (GPS)

– map the position of the vehiclesmap the position of the vehicles

– reconfiguration of the frequency pairsreconfiguration of the frequency pairs

– transmission of “special”transmission of “special” commands commands

Flexible operationFlexible operation– runs on any laptop connected runs on any laptop connected

to a radio modemto a radio modem

– may run on several locationsmay run on several locationssimultaneouslysimultaneously

Mission Tracking Mission Tracking SoftwareSoftware


Multifrequency acoustic beaconMultifrequency acoustic beaconMulti-channel transmitter and receiverMulti-channel transmitter and receiver

Programmable frequency pairsProgrammable frequency pairs

Simultaneous navigation of multiple vehiclesSimultaneous navigation of multiple vehicles

Medium frequency signals (20-30khz), over 2km rangeMedium frequency signals (20-30khz), over 2km range

Surface BuoysSurface BuoysStainless steel structureStainless steel structure

Polyurethane flotation disc Polyurethane flotation disc

GPS receiverGPS receiver

Radio modemRadio modem

Acoustic Navigation Acoustic Navigation NetworkNetwork


Multipurpose Surface BuoyMultipurpose Surface Buoy

Radio antenna

Fiberglass coated Polyurethane foam

Underwater cablesand connectors

Nylon/PVC cylinder

Acoustic transducerTo anchor

MultifrequencyTransponder

Acoustic navigation Acoustic navigation Moored sensorsMoored sensors Communication relayCommunication relay Waterproof container

Advanced Mission ConceptsAdvanced Mission Concepts


The PISCIS Project (2002-The PISCIS Project (2002-2005)2005)

ObjectivesObjectives– Development of a new generation AUVDevelopment of a new generation AUV– Simultaneous navigation of multiple AUVsSimultaneous navigation of multiple AUVs– Coordinated operation of AUVsCoordinated operation of AUVs– Specification and control of sensor driven missionsSpecification and control of sensor driven missions

LSTS ApproachLSTS Approach– Improvement in mechanical Improvement in mechanical

designdesign– Development of acoustic Development of acoustic

navigation systemsnavigation systems– Synthesis of controllers for Synthesis of controllers for

networked vehiclesnetworked vehicles

ConsortiumConsortium– FEUP, CIMAR, APDL, ISEPFEUP, CIMAR, APDL, ISEP


Advanced Mission ConceptsAdvanced Mission Concepts

Real-time adaptive samplingReal-time adaptive sampling– Model of oceanographic processesModel of oceanographic processes– Coarse survey to localize featuresCoarse survey to localize features– Track features and identify model parametersTrack features and identify model parameters

Cooperative missionsCooperative missions– Each vehicle makes a local measurementEach vehicle makes a local measurement– Vehicles share a minimum of dataVehicles share a minimum of data

Gradient followingGradient following– Detect and follow a given gradientDetect and follow a given gradient– Possibilities for single and multiple vehiclesPossibilities for single and multiple vehicles


Conclusions and Future Conclusions and Future WorkWork

SUMARE Workshop, Villefranche-sur-Mer, 15-16 October 2003 Artwork Courtesy of Michael Incze, NUWC

ConclusionsConclusions– The LSTS team has accumulated valuable expertise in development and integration of underwater The LSTS team has accumulated valuable expertise in development and integration of underwater

systems and technologiessystems and technologies– Low operational costs allowed for development validation by intensive field operationsLow operational costs allowed for development validation by intensive field operations– Research has been driven by end-user requirements and strongly influenced by mission resultsResearch has been driven by end-user requirements and strongly influenced by mission results

What’s ahead?What’s ahead?– New AUV expected to be tested during 2003New AUV expected to be tested during 2003– New AUV fully operational in 2004New AUV fully operational in 2004– Navigation of multiple AUVs expected during 2004Navigation of multiple AUVs expected during 2004– Coordinated operation of AUVs expected during 2004Coordinated operation of AUVs expected during 2004– Communication between AUVs, buoys and shore during 2004Communication between AUVs, buoys and shore during 2004– New sensors for ROV during 2004New sensors for ROV during 2004– Intervention capabilities for ROV during 2004Intervention capabilities for ROV during 2004

Thank You.Thank You.

Questions?Questions?

the underwater systems program at the porto university

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