Driving Characteristics of Robot Hand with Fingers using Langevin-Type Ultrasonic Motors

An ultrasonic motor is a promising actuator for robots since it has a simple construction, high response, and high torque at low speeds. This paper proposes a robot hand using Langevin-type ultrasonic motors as the fingers instead of moving elements. This robot hand with three fingers can simultaneously grasp and rotate a cylindrical body. The driving characteristics of the robot hand were examined experimentally under various conditions. It was confirmed that high torque was obtained when the optimum contact angle and contact force of the ultrasonic motors were used. The reduction of the output torque is small even when the diameter of the rotational body deviates from the designed value.