vision-based cooperative control experiment...system configuration system overview 11 vision-based...
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Tokyo Institute of Technology Fujita Laboratory
Vision-basedCooperative Control Experiment
Takahide Goto
FL08-14-12008-10-16
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Vision-based Cooperative Control Experiment
Table of Contents
IntroductionSystem OverviewVoronoi-based Coverage ControlOnboard CameraWii Remote OperationSummary
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Vision-based Cooperative Control Experiment
Outline
IntroductionCooperative Control
System OverviewVoronoi-based Coverage ControlOnboard CameraWii Remote OperationSummary
Introduction
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Vision-based Cooperative Control Experiment
Cooperative Control
A distributed control strategy that achieves specified tasks in multi-agent systemsIt has been motivated by interests in group behavior of animals, formation control of multi-vehicle systems, and so on
©James Jordanhttp://www.flickr.com/
Introduction
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Vision-based Cooperative Control Experiment
Cooperative Control
It is hoped to be applied to sensor networks, robot networks and many other multi-agents systems
Introduction
Coverage Control Pose Synchronization
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Vision-based Cooperative Control Experiment
Outline
IntroductionSystem Overview
e-nuvo WHEELSystem ConfigurationPrevious Experiments
Voronoi-based Coverage ControlOnboard CameraWii Remote OperationSummary
System Overview
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Vision-based Cooperative Control Experiment
e-nuvo WHEEL
Mobile Wheeled Inverted PendulumIt is internally-stabilized by the LQ controllerWe can send the target values (v, ω) via wireless LAN
System Overview
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e-nuvo WHEEL
Kinematic modele-nuvo WHEEL is regarded as a unicycle robot(v, ω) are controllableIt has a nonholonomic constraint
System Overview
Constraint:
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System ConfigurationSystem Overview
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Vision-based Cooperative Control Experiment
System Configuration
Controller: CentralizedInformation Acquisition: Centralized or Distributed
System Overview
Bird’s Eye CameraCentralized
Onboard CameraDistributed
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System ConfigurationSystem Overview
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Vision-based Cooperative Control Experiment
Previous ExperimentsSystem Overview
Attitude Synchronization Leader Following
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Outline
IntroductionSystem OverviewVoronoi-based Coverage Control
Voronoi DiagramLloyd’s AlgorithmEquilibrium BifurcationExperiments
Onboard CameraWii Remote OperationSummary
Voronoi-based Coverage Control
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Coverage Control
The goalAll mobile agents, placed initially at random, spread out as much as possible (efficiently) over a given area
CharacteristicsLarge scale of deployment Ability to withstand changes in environmentAbility to cope with node failures
ApplicationSensor networkEnvironmental monitoringSurveillance robotsetc
Voronoi-based Coverage Control
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Voronoi Diagram
Voronoi Cell Vi: The set of all points x whose distance from pi is less then or
equal to the distances form all other pj
Voronoi Diagram V:
Voronoi-based Coverage Control
: Distance Function
: Set of Points
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Voronoi DiagramVoronoi-based Coverage Control
Coloured 2D Voronoi diagramGNU Free Documentation License
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Voronoi Diagram
Such a diagram is often found as a territory behavior of nearly all major groups of organisms on the planet
Voronoi-based Coverage Control
Kamogawa, Kyoto
http://www.c-player.com/ac87205/thread/1100069985225
Water Strider
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Lloyd’s Algorithm
The method for evenly distributing nodes 1. Construct Voronoi Partition Vi, generated by pi
2. Update pi to be the centroid of Vi
3. Return to step 1. until convergence
Example (1D)
Voronoi-based Coverage Control
1 2 31 2 3
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Experiment SystemVoronoi-based Coverage Control
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Modeling
Consider N agents in a rectangular domain D with sides of length 1 and L
Voronoi-based Coverage Control
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Modeling
Voronoi cell for agent i at time step n is
with centroid
Agent i’s location at time step n+1 is
Voronoi-based Coverage Control
: the position of agent i
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a b c d
Modeling
Now we are interested in equilibrium configurations, that is, those for which
Such equilibria can be stable or unstable
Example (N=3, L=0.80)
Voronoi-based Coverage Control
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Unicycle Controller
e-nuvo WHEEL is used as a agent in experiment→ We have to design the controller to move it to an arbitrary
point
Astolfi’s Controller
Voronoi-based Coverage Control
: Gain
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Coverage Control ExperimentVoronoi-based Coverage Control
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Equilibrium Bifurcation Analysis
We treat L as a bifurcation parameterThe bifurcation results are independent of MBifurcation detection is performed by monitoring the eigenvalues of the linearized equations directlyAs a measure of an equilibrium configuration, we use
Where is the center of the domain D
Voronoi-based Coverage Control
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Equilibria Stability on 3 Agents
0.2 0.4 0.6 0.8 100
0.2
0.1
0.3
0.4
L
S
Voronoi-based Coverage Control
UnstableStable
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Equilibria Stability on 3 Agents
0.2 0.4 0.6 0.8 100
0.2
0.1
0.3
0.4
L
S
Voronoi-based Coverage Control
UnstableStable
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Bifurcation Experiment (Shrink)Voronoi-based Coverage Control
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Bifurcation Experiment (Stretch)Voronoi-based Coverage Control
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Bifurcation Experiment (Constant L)
L = 0.45
Voronoi-based Coverage Control
0.2 0.4 0.6 0.8 100
0.2
0.1
0.3
0.4
L
S
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Bifurcation Experiment (Constant L)
L = 0.70
Voronoi-based Coverage Control
0.2 0.4 0.6 0.8 100
0.2
0.1
0.3
0.4
L
S
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Outline
IntroductionSystem OverviewVoronoi-based Coverage ControlOnboard Camera
SpecificationExperiment SystemControl LawExperiment
Wii Remote OperationSummary
Onboard Camera
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Onboard Camera Specification
RF System RC-12Wireless Small Camera(15×18×35mm) 270,000 pixels
Onboard Camera
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Onboard Camera Specification
Image example
Onboard Camera
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Experiment SystemOnboard Camera
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Information Acquisition
Measuring area and horizontal deviation of the target
Onboard Camera
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The control input to follow the target:
If the area of target is very large, the follower stops to avoidcollision
If the follower loses the target, the control input is maintained at the last value
The follower acts like a search behaviorThis rule also eliminates the effect of fraction
Control LawOnboard Camera
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ExperimentOnboard Camera
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Outline
IntroductionSystem OverviewVoronoi-based Coverage ControlOnboard CameraWii Remote Operation
FeaturesMeasurement of TiltRobot Operating SystemExperiment
Summary
Wii Remote Operation
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Main Features
The primary controller for Nintendo's Wii console Wireless communication with the console via BluetoothArrow key and 7 buttonsAccelerometer to sense acceleration along 3 axesOptical sensor to determine where the Wii Remote is pointing
Wii Remote Operation
Wii www.nintendo.co.jp
Wii Remote
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Why Wii Remote?
Intuitive interface of robot operationBuilding the operator into the feedback loop (human-in-the-loop)
Wii Remote Operation
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Measurement of TiltWii Remote Operation
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Robot Operating SystemWii Remote Operation
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Robot Operating SystemWii Remote Operation
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Vision-based Cooperative Control Experiment
Robot Operating ExperimentWii Remote Operation
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Outline
IntroductionSystem OverviewVoronoi-based Coverage ControlOnboard CameraWii Remote OperationSummary
Summary
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Summary
Voronoi-based Coverage ControlCoverage AlgorithmEquilibrium Bifurcation AnalysisExperiments
Onboard CameraInformation AcquisitionControl Law of Following the ballExperiment
Wii Remote OperationMeasurement of TiltRobot Operating Experiment
Summary
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Future Works
Visual ObserverDistributed ControllerHuman-in-the-loop
Summary