Design of Compliant Joints and Human-Robot Connection in an Ankle-Foot Exoskeleton

This paper presents the design of compliant ankle and toe joints and a human-robot connection in an ankle-foot exoskeleton. The ankle joint driven by an adapted series-elastic actuator is proposed to provide sufficient power to assist the wearer in daily locomotion. In order to obtain a human-like toe joint with compliance, the toe joint is driven by a cable-driven actuator with both series and parallel elasticity. The parallel elasticity is used to decrease the required motor power by storing elastic energy. In addition, a passive two-degree-of-freedom human-robot connection including a revolution joint and a slider is designed to protect the wearer from uncontrollable forces which are induced by hyperstaticity.