Exploiting Natural Dynamics in Exploiting Natural Dynamics in the Control of a 3D Bipedal the Control of a 3D Bipedal

Walking SimulationWalking Simulation

Jerry Pratt, Gill PrattJerry Pratt, Gill Pratt

MIT Leg LaboratoryMIT Leg Laboratory

www.ai.mit.edu/projects/leglab/www.ai.mit.edu/projects/leglab/

M2 M2 3D Biped -- 12 DOF3D Biped -- 12 DOF

Designed by Daniel Paluska and David Robinson

M2 SimulationM2 Simulation3D Biped -- 12 DOF3D Biped -- 12 DOF

Spring FlamingoSpring FlamingoPlanar BipedPlanar Biped

6 DOF6 DOF

OutlineOutline

• Background:Background:– Previous WorkPrevious Work– Series Elastic ActuatorsSeries Elastic Actuators

• Natural Mechanisms for WalkingNatural Mechanisms for Walking

• Planar Robot Algorithm and Results Planar Robot Algorithm and Results

• 3D Simulation Algorithm and Results3D Simulation Algorithm and Results

• Conclusions and Future WorkConclusions and Future Work

Background: Previous WorkBackground: Previous Work

Background: Previous WorkBackground: Previous Work

Background: Previous WorkBackground: Previous Work

• Passive Dynamic WalkersPassive Dynamic Walkers– Natural LookingNatural Looking

– EfficientEfficient

– Simple (No) ControlSimple (No) Control

• Powered Bipedal RobotsPowered Bipedal Robots– Capability PotentialCapability Potential

– Practical/Market PotentialPractical/Market Potential

– Biological Similarity Biological Similarity PotentialPotential

PassiveWalkers

PoweredWalkers

Background: Background: Series Elastic ActuatorsSeries Elastic Actuators

MotorGearTrain

SeriesElasticity

Load

ForceSource

Load

Background: Background: Series Elastic ActuatorsSeries Elastic Actuators

Background: Background: Series Elastic ActuatorsSeries Elastic Actuators

Designed by David Robinson and Daniel Paluska

OutlineOutline

• BackgroundBackground• Natural Mechanisms for WalkingNatural Mechanisms for Walking

– KneecapKneecap– Compliant AnkleCompliant Ankle– Passive SwingPassive Swing

• Planar Robot Algorithm and Results Planar Robot Algorithm and Results • 3D Simulation Algorithm and Results3D Simulation Algorithm and Results• Conclusions and Future WorkConclusions and Future Work

KneecapKneecap

KneecapKneecap

Compliant AnkleCompliant Ankle

Compliant AnkleCompliant Ankle

Passive SwingPassive Swing

OutlineOutline

• BackgroundBackground

• Natural Mechanisms for WalkingNatural Mechanisms for Walking

• Planar Robot Algorithm and ResultsPlanar Robot Algorithm and Results

• 3D Simulation Algorithm and Results3D Simulation Algorithm and Results

• Conclusions and Future WorkConclusions and Future Work

Spring FlamingoSpring FlamingoPlanar BipedPlanar Biped

6 DOF6 DOF

Planar Robot AlgorithmPlanar Robot Algorithm

Planar Robot AlgorithmPlanar Robot Algorithm

• HeightHeight: Constant vertical : Constant vertical force.force.

• PitchPitch: PD controller on : PD controller on stance leg.stance leg.

• Swing LegSwing Leg: Mostly Passive.: Mostly Passive.

• SpeedSpeed: Naturally stable for : Naturally stable for slow speeds.slow speeds.

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Robot Strobe PhotoRobot Strobe Photo

Planar Robot AnimationPlanar Robot Animation

Physical Robot Walking DataPhysical Robot Walking Data

OutlineOutline

• BackgroundBackground

• Natural Mechanisms for WalkingNatural Mechanisms for Walking

• Planar Robot Algorithm and Results Planar Robot Algorithm and Results

• 3D Simulation Algorithm and Results 3D Simulation Algorithm and Results

• Conclusions and Future WorkConclusions and Future Work

M2 SimulationM2 Simulation3D Biped -- 12 DOF3D Biped -- 12 DOF

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3D Simulation Algorithm3D Simulation AlgorithmTitle:sim_state_machine.epsCreator:fig2dev Version 3.2 Patchlevel 0-beta2Preview:This EPS picture was not savedwith a preview included in it.Comment:This EPS picture will print to aPostScript printer, but not toother types of printers.

3D Simulation Animation3D Simulation Animation

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Simulation DataSimulation Data

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OutlineOutline

• BackgroundBackground

• Natural Mechanisms for WalkingNatural Mechanisms for Walking

• Planar Robot Algorithm and Results Planar Robot Algorithm and Results

• 3D Simulation Algorithm and Results3D Simulation Algorithm and Results

• Conclusions and Future WorkConclusions and Future Work

ConclusionsConclusions

• Passive Mechanisms Helped Make ControlPassive Mechanisms Helped Make Control– SimpleSimple– EfficientEfficient– Natural LookingNatural Looking

• Actuators with Negligible Dynamics are Actuators with Negligible Dynamics are ImportantImportant

• Decoupled Controller Works well for 3D Decoupled Controller Works well for 3D Simulation Walking StraightSimulation Walking Straight

Future WorkFuture Work

• Faster WalkingFaster Walking

• More Robust AlgorithmMore Robust Algorithm

• Biologically Similar AlgorithmBiologically Similar Algorithm

• Automatic Tuning, LearningAutomatic Tuning, Learning

• Central Pattern GeneratorsCentral Pattern Generators

• 3D Robot3D Robot

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What Next?What Next?