Regulated Sliding Mode Control of a Biped Robot

Control of biped robots based on designated smooth and stable trajectories is a challenging problem that is the focus of this article. A desired trajectory for the lower body will be designed to alleviate the impacts due to contact with the ground. Then, the upper body motion is planned based on the Zero Moment Point (ZMP) criterion to provide a stable motion for the biped robot. Next, dynamics equations will be obtained for both single support phase (SSP) and double support phase (DSP). Finally, the Sliding Mode Control (SMC) approach is applied for both SSP and DSP. To this end, a new chattering elimination method will be proposed to regulate major controller parameters. Obtained results show that the performance of the SMC in terms of the tracking errors will be fine even in the presence of considerable uncertainties and exerted disturbances. Also, the new proposed method substantially reduces chattering effects in the control of the biped robot.