Achievement of complex contact motion with environments by musculoskeletal humanoid using humanlike shock absorption strategy

Abstract

We have been developing and studying musculoskeletal humanoids. Our goal is to realize more human-like humanoids which can do natural and dynamic motions as well as humans. Especially motions with complex contact with environments, which is jumping, running, catching a ball, and landing on one's hands, etc, are difficult to be achieved by humanoids. To achieve that motions, robots have to absorb shock force so as not to break ones' body structures, such as gears, motors, body links and so on. Musculo-skeletal humanoids are suited for these situations, because they can easily have mechanical flexibilit for shock absorption by adding elastic units, which is nonlinear spring units, to its own tendons. In this paper, we propose shock absorption methods by musculoskeletal humanoids, which uses its own mechanical flexibilit and simple refle of each muscles based on tension sensor. This strategy is inspired by human's motion control, and it can achieve shock absorption tasks without any fast sensor feedback controls and any prediction ocntrols used by conventional robots with rigid bodies. We chose a catching a ball task as an example of complex contact motions, implemented the proposed strategy to musculoskeletal humanoid Kenzoh and confirme the feasibility of proposed method by actually catching a ball demonstration.