Computed torque controller for an 8 degrees of freedom biped robot based on Zero Moment Point

Abstract

Biped robot requires a control system to ensure the stability of the robot during walking. Computed torque control approach is a special application of feedback linearization of nonlinear system which also appears in robust control, adaptive control, learning control, and so on. This paper first introduces a newly designed mechanism, an 8 degree of freedom (DOF) biped robot, which designed in SolidWorks. Then it presents a human like walking trajectories for the feet and the hips in order to achieve smooth and continuous walking. We will obtain inverse kinematic to find desire angles and velocities and accelerations for controller. An accurate model for the related biped robot is computed and applied to the controller. Then we describe computed torque controller and introduce a way for adjusting the controller gains. Off-line Zero Moment Point (ZMP) is used for stability of biped robot. Finally, the effectiveness of controller is illustrated by simulation results.