Proposal of a flexible translational joint mechanism for humanoid robots

Recently, applications of robots for home assistant, helper and rehabilitation have attracted considerable attention, and various humanoid robots are developed. In such environments, robots have to handle unexpected disturbance very quickly. Especially, external forces owing to collision to obstacles or people are one of significant problems, because they causes risks to injure human bodies or to break own structures. However, almost conventional robots consist of rigid structures, so, many sensors and high-spec controller is required for handling external forces. To address this problem, flexible structures like a muscle have attracted considerable attentions. By employing flexible structures, we can reduce sensors and controllers, because the flexible structures can adapt themselves to the unknown environment by utilizing their physical properties without sensors or controllers. In this paper, we focus on flexible mechanism, and propose a flexible translational joint of which flexibility can be adjusted adaptively. We employ the proposed flexible joints for legs of a humanoid robot, and we conduct experiments of walking on vibrated plane. As the result, we confirm that the developed humanoid robot can walk on the vibrated plane, due to the filtering properties of the flexible joints.