Robot hand with fingers using vibration-type ultrasonic motors (driving characteristics)

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 vibration-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.