Biped Robot Walking Using Gravity-Compensated Inverted Pendulum Mode and Computed Torque Control

This paper proposes a model called the gravitycompensated inverted pendulum mode (G CIPM) to generate a biped locomotion pattern that is similar to the one generated by the linear inverted pendulum mode, but accommodates the free leg dynamics based upon its predetermined trajectory. When the biped locomotion based upon the linear inverted pendulum mode is applied to real biped robots, the stability of the robot is disturbed due to the fact that the neglected dynamics offree legs is not actually negligible, moving the Zh4P (zero moment point) away from the presumed jixed point. The GCIPM includes the effect of the dynamics of the free leg in a simple manne~ This paper also presents a control method for biped robots based upon the computed torque. Simulation results show that the biped robot is more stable with the walking pattern generated by the proposed method combined with the controller than with the one by the inverted pendulum mode.