Development of a Novel Actuation Mechanism For a Legged Robot With Mono- and Bi-articulated Drive and Parallel Elasticity

Bi-articular actuation in animal legs is a key feature in increasing the stability of the postural control and the toe output. In addition, the parallel elasticity of the mono- and bi-articular muscles increases the toe stiffness and improves the legs’ robustness. In this study, we proposed a novel actuation mechanism for a legged robot, which has mono- and bi-articular drive functions and parallel elasticity inspired by a biological muscle-tendon complexes group. We developed a prototype of one-legged robot equipped with the proposed actuation mechanism. The effectiveness of the parallel elastic mechanisms and mono- and bi-articular drive was validated through forward jumping simulation. The experimental result using the prototype demonstrated the robot achieved forward jumping motion of more than twice its leg length.