WALKING CONTROL ON UNKNOWN AND UNEVEN TERRAIN FOR BIPED ROBOT WITH SPRING EMBEDDED FEET

This paper presents a walking control method to achieve stable biped walking on unknown and uneven terrain. It is important to suppress an impact force and to place a foot on the actual ground for landing on such terrain. Because the conventional foot generally has a rigid body, it is difficult to suppress the impulsive reaction force. We first propose to attach a spring on each foot to reduce the impulsive reaction force. Then, to achieve these two objectives simultaneously by adjusting the foot position, this paper presents a PI force controller with a desired foot position to land on unknown terrain. This controller provides the robust stability of control system with respect to terrain variance and exact positioning of the foot to actual ground. This controller is applied to a simple biped robot that has spring embedded feet. The effectiveness of the proposed walking control method on uneven terrain is demonstrated by using a dynamic simulator.