Realization of Dynamic Walking of Biped Humanoid Robot HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology Jung-Yup Kim

Jung-Yup Kim Biped Walking Basic Structure for Biped Walking Observation Human Walking Motions Simple Dynamic Model Walking Pattern Planning (slow process) Biped Walking Posture Stabilization (fast process) Online Controller Design Based On Sensory Feedback Vibration Controller ZMP Compensator Landing Position Controller Landing Timing Controller . System ID Based on Experiments HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology Jung-Yup Kim

Jung-Yup Kim - basically cyclic function Walking pattern design parameters Description Value Apelvis Lateral swing amplitude of pelvis 32 (mm) Hfoot Maximum elevation of foot 40 (mm) Tstride Walking period (stride time) 1.9 (seconds) Tstep Step time 0.95 (seconds) Tdelay Delay time 0.2 (second) Double support ratio 0.05 (5 %) Tssp Single support time Tdsp Double support time Cosine function is used to generate smooth curve - basically cyclic function - easy to prevent velocity discontinuity - easy to differentiate the function Jung-Yup Kim HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology

Jung-Yup Kim • Online Control Structure + - Walking Parameters Setting : Step length, step period, DSP ratio … Walking Pattern Control (WPC) Walking Type Selection : Go forward/backward, Turning around, Go aside Torso Roll & Pitch Controller Walking Pattern Generation Real-Time Balance Control (RTBC) Pelvis Swing Amp. Controller Upright Pose Controller Inverse Kinematics Landing Position Controller Cartesian Space + - Joint Space Tilt Over Controller Soft Landing Controller PD controller Vibration controller ZMP Compensator Landing Timing Controller HUBO Predictive Motion Control(PMC) Landing Detection Jung-Yup Kim HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology

Walking Pattern Control Modifies the walking pattern at every walking cycle. Learning strategy : Jung-Yup Kim HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology

Activation Time Table of Online Controllers Grey box : controller is active. HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology Jung-Yup Kim

(1) Vibration Control Jung-Yup Kim Objective : Suppress the vibrations due to the joint compliance. (a) Vibration control of torso Jung-Yup Kim HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology

(1) Vibration Control Jung-Yup Kim Objective : Suppress the vibrations due to the joint compliance. (b) Vibration control of swing foot Jung-Yup Kim HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology

Jung-Yup Kim Modeling u + - HUBO Lab, Humanoid Robot Research Center, Mathematical Model Equation of motion Transfer function Modeling where, : Desired ankle joint angle : Actual ankle joint angle : measured torque at F/T sensor Torque of ankle joint Ref. input of ankle joint u + Feedback Control - HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology Observer Damping ratio can be assigned freely by changing kd Observer equation Jung-Yup Kim

Jung-Yup Kim HUBO Lab, Humanoid Robot Research Center, Root-Locus : Closed loop pole Experimental Results Jung-Yup Kim HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology

Jung-Yup Kim - HUBO Lab, Humanoid Robot Research Center, Mathematical Model Equation of motion Hip Pitching Joint Hip Roll Joint Swinging leg Swinging leg Transfer function Supporting leg Supporting leg Coronal Plane View Sagittal Plane View : Desired hip joint angle : Actual hip joint angle Feedback Control Lead compensator Plant - Double Integrator Accelerometer Jung-Yup Kim HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology

Jung-Yup Kim HUBO Lab, Humanoid Robot Research Center, Root-Locus Damping ratio can be increased !! : Closed loop pole Experimental Results Jung-Yup Kim HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology

(2)ZMP Compensator Jung-Yup Kim Objective : Maintain dynamic balance all the time. Pelvis Center Transverse Plane Z Z Z Y Y Y ZMP X X X Mode 1 (Double Support Phase) Mode 2 (Double Support Phase) Mode 3 (Single Support Phase) Horizontal pelvis motion on the transverse plane is used for the ZMP compensation Jung-Yup Kim HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology

Jung-Yup Kim 1) For Mode 3 (Single Support Phase) : System identification using frequency response test Bode Plot Jung-Yup Kim HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology

Jung-Yup Kim 2) For Mode 1 and 2 (Double Support Phase) : System identification using a simple inverted pendulum model Laplace Transform We can derive unknown K, l through simple experiments !!! Jung-Yup Kim HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology

Jung-Yup Kim Pole placement and step response simulation Feedback Control + - Jung-Yup Kim HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology

Jung-Yup Kim Experimental results (Mode 3) Video Steady-state error is nearly zero ! Video Jung-Yup Kim HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology

(3) Landing Position Control Objective : Find out best landing position at every step. Just before landing Just after landing Impulse-Momentum Principle on the Coronal Plane : HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology Jung-Yup Kim

Jung-Yup Kim Principle HUBO Lab, Humanoid Robot Research Center, The moment of inertia is constant Angular impulse ------ (1) Desired angular momentum after landing (constant) Measured angular momentum before landing (variable) Control Input ------ (2) By the way, Moment of ankle joint at ground contact (constant) Finally, HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology Jung-Yup Kim

Jung-Yup Kim Experimental results Video Without control With control Without control With control HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology Jung-Yup Kim

(4) Landing Timing Control Objective : Find out best landing time at every step. Stable region Prescribed left foot height Prescribed right foot height A B A B Angular velocity of body Angular Velocity[deg/s] or Displacement[mm] E Time [sec] ZCP(Zero Crossing Point) (inside tilt over case) E ZCP(Zero crossing point) (normal case) (Coronal Plane View) Compensated right foot altitude Angular velocity, HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology Jung-Yup Kim

(5) Stable Landing Control Objective : Absorb the landing impact at every step. Sagittal plane view Impedance Control : Virtual Spring & Damper 1 Virtual Spring & Damper 2 T F HUBO Lab, Humanoid Robot Research Center, Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology Jung-Yup Kim