Impact force reduction for biped robot based on decoupling COG control scheme

The paper describes a novel approach to control a biped robot for the stable gaits. The target is to achieve to reduce the impact force with the ground when the swinging leg comes into contact with it. In our approach, redundant legs are introduced for the biped, and the decoupling control system are applied, which consists two independent control laws. One of the laws is for the hip position control, the other the center of gravity (COG) position of a leg. The COG position control is based on the mechanical impedance control scheme, and the position is actively controlled for the purpose of the impact force reduction. The validity of our method is confirmed in physical experiments using actual biped robot.