In the case of mechanical contact between humans and robots including motion-support robots or robotic orthosis, safety is most important. Therefore, in the motion-support robot presented in this paper, hexahedron rubber actuators (HRA) which have light weight, small size and flexibility of motions are used. In this paper, the basic performance of an antagonized HRA unit which is actuated by air pressure is revealed at first. Moreover, effectiveness of a motion-support robot with 4 DOF is demonstrated through experimental results.

A new type of pneumatic rubber actuators is proposed in this paper. The proposed actuator has a hexahedron structure which is suitable for making a rotational joint of a robot. We reveal the static characteristics of the actuator. It is experimentally demonstrated that a position feedback control law realize fast motions without oscillation. Moreover, we propose an adaptive gain method for the actuator to improve control performance. The effectiveness of the proposed method is confirmed through an experiment.