Abstract
To realize medical and welfare robots, which are able to move like a human arm and hand, a pronation robot arm system (155g in weight and 300mm in length) was developed. This system had a goal of rotation a knob of the door in the daily life of patients and was composed of the Shape Memory Alloy, which performs as a human muscle. From the results of the system evaluation, the aimed goal was accomplished in the mechanical pronation properties of movement angle, of torque, and of angular velocity.