Design of a novel ultrasonic spherical motor

This paper presents a novel ultrasonic spherical motor. With only a single moving part, this spherical motor is capable of providing 2-DOF motions required for micro satellite and space robot actuation. The operating principle of the motor is explicated and an initial prototype was fabricated and tested. The elliptical trajectories of the rotor tip were observed via two MTI Fotonic 2000 displacement probes. The feasibility of the working principle was verified using a normal ball bearing held on to the top of the rotor, and a fast spinning of the ball-bearing occurs at resonant frequencies of 10.67, 18.9 and 28.9KHz respectively. Finally, further improvement issues of the motor are briefly discussed.