Development of a novel leg mechanism in the shape of backward convex with a mechanical joint stop for bipedal robot

The realization of natural, fast and versatile motions for bipedal robots is still a challenge topic. As one approach to enhance the performance of bipedal robots, actuation with high backdrivability, high power-to-weight ratio as well as high torque is necessary. In this paper, a novel mechanism of leg in the shape of backward convex with a mechanical joint stop is proposed to reduce the necessary torque by the actuator in knee joint and then to improve the actuation capability of knee joint and reduce the consuming energy by the actuator while by a light structure. The design method including simulation for the mechanism is described. A prototype of the leg robot has been developed and the basic feasibility of the mechanism is shown by experimental results.