Fault Mitigation and Fault Tolerant Humanoid System Against Contact Impact

Humanoid robots are expected to expand their activity locations to narrow or uneven environments. When robots operate in a narrow space or on uneven terrain, they receive unplanned contact impacts, resulting in falling down or malfunctioning. Therefore, in humanoid systems, (1) balance control, (2) self-state estimation, and (3) in-body communication must have both fault mitigation and fault tolerance against contact impact. In this paper, we propose a system where robot can cope with contact impact through flexible contact by torque control, correction of estimation using contact state changes, and error tolerant communication based on control cycles. We verified the effectiveness of the proposed method through experiments of walking outdoors continuously, moving into a narrow environment, retrieving an object, and transporting an object over uneven terrain using the life-sized humanoid robot JAXON.