Virtual passive dynamic walking and energy-based control laws

It has been shown that a simplest walker with suitable parameter choice can walk down a gentle slope without any control forces and generate its steady walking pattern utilizing gravity effect automatically. On the floor, however, the robot cannot exhibit passive walk, so any application methods of passive walk to active walker on the horizontal floor has not been studied yet. In this paper we introduce “virtual passive dynamic walking” with virtual gravity field which acts as a driving force for the biped robot. The robot can walk on the floor without any control torque except virtual gravity effect. Since the modified gravity field seems to be very close to real condition, the generated walking pattern seems to be natural. Further, multi-pattern walking with respect to energy level is proposed. With the proposed method, safety and energy-effective control of biped walking robot can be realized