Abstract
We have studied a differential gear transmission for low-speed drive of ultrasonic motor. This transmission outputs the difference of two ultrasonic motors, therefore it can output very low speed when both motors move at close speed in the ounter direction, and it outputs the same speed as the maximum of single motor, when both motors moves at maximum speed in the same direction. Such wide speed selectivity is useful for path control of MRI-compatible manipulator/robot, because MRI-compatibility needs ultrasonic motor, which however has narrow speed selectivity. In this paper, we reported its structure, kinematics, and speed selectivity against minimum speed of ultrasonic motor.
