Development of An Artificial Arm by Using a Spherical Ultrasonic Motor.

This paper presents a new artificial arm for physically handicapped people by using a spherical ultrasonic motor. The ultrasonic motorhas high performance such as it has high torque at low speeds, high holding torque, no braking mechanism, no magnetic noise, a gear is unnecessary and the motor can be driven silently. Especially, a spherical ultrasonic motor has these characteristics and three degrees-of-freedom in one unit which is similar to the joint of the human being. In additional, newly developed a small size ultrasonic motor and a high output torque type of ultrasonic motor which called a sandwich type ultrasonic motor. In this paper a spherical ultrasonic motor and a sandwich type ultrasonic motor are attempted to apply an artificial arm. Then the artificial arm has a spherical ultrasonic motors on a wrist joint, and it also has a three-finger hand by using a small size ultrasonic motor. The artificial arm by using shperical ultrasonic motor shows good maneuverability and excellent controllability.