Impedance and Force Compliant Control for Bipedal Robot Walking on Uneven Terrain

In this paper, we propose a leg compliance method and strategies for ZMP-based bipedal walking robot on continuous uneven terrain without gyro sensor by combining soft joint, impedance, force and position control. We divide biped robot into support leg and swing leg to apply different control methods, and distinguish period of swing leg into four procedures, which adopt different strategies. By this way, robot achieves walking on uneven slope. Besides, when robot walks on normal flat ground, the proposed compliant landing method can also decrease the impact of ground reaction force (GRF) and reinforce stability during transition from single support phase (SSP) to double support phase (DSP). The validity of the proposed approach and strategies are verified and achieved with experiment biped robot in our lab.