A consideration on biped lateral motion planning with robot experiment of adaptive frontal-plane stepping

In this paper, an method for biped lateral motion control is discussed, taking into consideration that the main purpose of frontal-plane is the stabilization of the inverted pendulum. Usually, the ZMP criterion is adopted to the biped control. However, the joint or the CoG reference trajectories generated based on the ZMP criterion sometimes have to be modified in relation to environmental changes. From this point of view, a control method without their reference trajectories is proposed for the biped frontal-plane motion. This control method using ground reaction force information is equivalent to the ZMP feedback control. The experiments of a biped robot whose degrees of freedom of motion is limited in the frontal plane demonstrate the effectiveness of this control method.