Point-contact type foot with springs and landing control for biped walking on rough terrain

This paper proposes a biped robot with a point-contact type foot with springs (PCFS) and its control method for stable locomotion on rough terrain. PCFS is a new foot system that was proposed in our previous study. Realizing stable walking on rough terrain is important, because biped robots are expected to assist humans in not only a flat known environment but also on rough ground surfaces with terrain variances while maintaining their usefulness. PCFS realizes stability on complex ground surfaces and suppresses the impact force at the foot landing. To adjust a foot position and posture in response to the declination between the predicted ground surface and the actual ground surface, we propose a landing controller for uncertain rough terrain. This proposed controller provides exact positioning to the actual ground without excessive reaction force and robust stability with respect to terrain variance. The biped robot implements these proposed approaches, and their effectiveness is demonstrated by simulation and experimental results.