Design of powerful and flexible musculoskeletal arm by using nonlinear spring unit and electromagnetic clutch opening mechanism

We have been developed and studied musculoskeletal humanoids. Our next motivation is to achieve more human-like humanoids which can do natural and dynamic motions as well as humans. We newly designed musculoskeletal tendon-driven arm, which can achieve humanlike body structure, flexibility of joints and great power of joints for this motivation. This paper describes how to design such an arm and proposes the key mechanical design points, which is compact nonlinear spring unit and winding pulley equipped with electromagnetic clutch releasing mechanism. To show that these mechanisms improve greatly joint angular speed, we developed simple testing tendon-drive arm with these mechanism and did verification experiments. Finally, we present life sized musculoskeletal arm using these mechanisms and some demonstrations.