Dynamic gait control of biped robot based on kinematics and motion description in Cartesian space

Abstract

A novel dynamic gait control method of biped robots based on robust joint servo control is proposed in this paper. The method consists of two steps. The first step is the approximation of the biped robot to the inverted pendulum for the sagittal plane and lateral plane. The second step is the constitution of dynamic gait control based on robust joint servo control and kinematics. The motion description in Cartesian space is determined from the motion of the inverted pendulum in the sagittal plane and lateral plane. Suitability of the biped motion reference is confirmed by distribution of ZMP (Zero Moment Point). Using the inverse kinematics of the biped robot, the biped motion reference in Cartesian space is transformed to the position references in joint space. In joint space, the robust position control system consists of two-degree-of-freedom control system based on coprime factorization and disturbance observer. Since the robust joint servo control system compensates the inertia variation and disturbance torque on dynamic gait control, this control system is suitable for the dynamic gait control of the biped robot. The validity of the proposed method is confirmed by the experimental results. © 1999 Scripta Technica, Electr Eng Jpn, 129(4): 96–104, 1999