Computed Torque and Proportion-differential Feedback Control for Robot Bionic Knee Joint

WANG Binrui¹  JIN Yinglian¹  XU Hong¹  XU Xinhe²

(1. School of Mechanical and Electrical Engineering, China Jiliang University, Hangzhou 310018;
2. Institute of Artificial Intelligent and Robot, Northeastern University, Shenyang 110004)

Abstract: With varying instant central of rotation, 4 links knee joint controlled by magnetic rheclogical intelligent damper is more bionic than 2 links joint. But its machine model is complex, and rotation motion control is a difficult nonlinear time varying system’s tracking control. Firstly, virtual prototype and dynamic model of biped robot leg with 4 links bionic knee joint, and Bingham model of MR damper are built. Secondly, based on the centre of instant central rotation and joint geometry, a simplified model is presented. Thigh and crus length changing is computed in the proposed model to reduce model errors. Computed torque and PD feedback control algorithm is put forward and designed for robot leg swing motion control. According to Lyapunov function, the convergence is proved based on dynamic model with modeling errors. The simulations on virtual prototype and sample machine test are done. The relation between MR damper force and knee joint rotation gait is illustrated. All results indicate that using instant centre of rotation and varying link length in dynamic modeling can reduce model errors. Based on the proposed simplified model, computed torque and PD feed back control is good for walking control of biped robot with 4 links bionic knee joint.

Key words: Robot  Bionic joint  Magnetic rheological intelligent damper  Computed torque control  Convergence

CLC No: TP242

国家自然科学基金资助项目(60475036). Received 20070308, received in revised form 20070916