Introduction of Toe Mechanism with Bi-articular Tendon into Legged Robot

In recent years, bio-inspired robots have been researched in order to realize dynamic motions like animals. Focusing on animals' dynamic motions, toes are considered as important mechanisms. In the toes, there are a muscle and tendon that flex the toe joint and extend the ankle joint. The coupled movements between ankle and toe joints can be realized by using the muscle and tendon. The tendon is allowed to store and reuse elastic energy by releasing it during motion. In order to improve the performance of dynamic motion, a toe mechanism inspired by the tendon over the two joints is introduced into our legged robot. In this paper, a toe mechanism with bi-articular tendon consisting of tension spring, cable and pulleys is proposed. Design parameters were determined by simulation, and jumping experiments were carried out using a legged robot with this mechanism. As a result of the experiments, the jumping height of the legged robot with this mechanism has been improved.