Biped RobotsBiped Robots

DefinitionsDefinitions

Static WalkingStatic Walking The centre of gravity of the robot is The centre of gravity of the robot is

always within the area bounded by the always within the area bounded by the feet that are touching the groundfeet that are touching the ground

Dynamic WalkingDynamic Walking At significant periods during the gait the At significant periods during the gait the

centre of gravity of the robot is outside of centre of gravity of the robot is outside of the area bounded by the feet that are the area bounded by the feet that are touching the groundtouching the ground

HistoryHistory

Dynamic Walking ToysDynamic Walking Toys Static Walking Wind up ToysStatic Walking Wind up Toys Static Walking RobotsStatic Walking Robots Dynamic Walking RobotsDynamic Walking Robots

Research LabsResearch Labs

MIT AI LabMIT AI Lab Waseda UniversityWaseda University HanYang UniversityHanYang University Honda LabsHonda Labs Sony LabsSony Labs

The Walking ProblemThe Walking Problem

Design a gait sequence in joint spaceDesign a gait sequence in joint space Provide sensors and actuators at Provide sensors and actuators at

jointsjoints Implement a PID controller at each Implement a PID controller at each

jointjoint Command the PID controllers to Command the PID controllers to

follow gait sequencefollow gait sequence

ChallengesChallenges

Designing gaits that don’t violate the Designing gaits that don’t violate the maximum torque availablemaximum torque available

PID controller will not be able to generate PID controller will not be able to generate the large torque until the error between the large torque until the error between the gait and actual joint angle becomes the gait and actual joint angle becomes too large.too large.

Gait design is a time consuming process Gait design is a time consuming process that is difficult to implement online in that is difficult to implement online in real timereal time

Raibert’s One Legged RobotRaibert’s One Legged Robot

One LeggedOne Legged Hopping/RunningHopping/Running Simple Dynamic ModelSimple Dynamic Model

Leg Lab’s Spring FlamingoLeg Lab’s Spring Flamingo

Planar biped robotPlanar biped robot Linear actuatorsLinear actuators Inverted kneesInverted knees Toe Lift offToe Lift off

Leg Lab’s M2Leg Lab’s M2

3D biped3D biped Linear actuatorsLinear actuators

Waseda’sWaseda’s

Early 3D bipedEarly 3D biped

KAIST’sKAIST’s

DC motorsDC motors ServomotorsServomotors Onboard cameraOnboard camera

Singapore Polytechnics Singapore Polytechnics RoboerectusRoboerectus

ServomotorsServomotors Gait defines servomotor setpointsGait defines servomotor setpoints

Honda’s Asimo & P3Honda’s Asimo & P3

Commercial humanoidCommercial humanoid Well defined tasksWell defined tasks General Intelligence requiredGeneral Intelligence required

Sony’s BPSony’s BP

Entertainment RobotEntertainment Robot Commodity StructureCommodity Structure Stereo visionStereo vision

Designing GaitsDesigning Gaits

Controlling BalanceControlling Balance when standing, “not required” when walkingwhen standing, “not required” when walking

Controlling SpeedControlling Speed change step size (swing leg must keep up)change step size (swing leg must keep up)

Controlling HeightControlling Height used to control speed and energy efficiencyused to control speed and energy efficiency

Generate intermediate joint angles based on Generate intermediate joint angles based on these constraintsthese constraints

Biped Robot SimulatorsBiped Robot Simulators

Kinematic SimulatorsKinematic Simulators for gait designfor gait design

Dynamic SimulatorsDynamic Simulators for control system testingfor control system testing

Yobotics Simulation Construction SetYobotics Simulation Construction Set dynamic simulation of linked dynamic simulation of linked

mechanismsmechanisms