Downsizing of wearable HEXA for a shoulder joint of wearable robot

Developing a more downsized joint for wearable robots is an important issue. Especially, development of a downsized joint which can be worn around a human shoulder is considered to be a challenging issue, because a human shoulder realizes very large motion range of an upper arm. This paper discusses downsizing of a 6-DOF mechanism for a shoulder joint of wearable robots, which is referred to as "wearable HEXA (W-HEXA)" and has been developed by the authors. An optimization problem is formulated in order to find a set of kinematic parameters which realizes a more downsized W-HEXA, and the problem is solved by genetic algorithm. Through examination of a prototype, it is demonstrated that the downsized W-HEXA developed in this study is capable of satisfactorily covering the motion range of a human upper arm.