Design and performance evaluation of a noncontact rotation actuator driven by near-field ultrasonic energy

The innovation of novel drive methods based on smart materials is an important way to promote the development of machines and equipment to the direction of high speed, high efficiency, clean and intelligence. Based on the piezoelectric drive principle and near-field acoustic levitation (NFAL) technology, a noncontact rotation actuator is proposed driven by ultrasonic energy. Under the action of ultrasonic energy generated by the ultrasonic emitter, the object can be stably levitated and driven to rotate at a certain speed. The electroacoustic conversion structure of the actuator is designed and its performance parameters are predicted. To verify the levitation and driving performance, a testing system for the actuator is developed. The structural and dynamic parameters’ influence on the rotor motion are investigated by experimental means, and the optimal parameter combination is acquired. The experiment results show that the maximum driving speed of the optimized rotor can reach 3145 rpm and the maximum noncontact driving torque is about 1.24 mNm under the excitation frequency of 20.21 kHz and the excitation voltage of 225 V_p-p. The proposed levitating drive method based on ultrasonic energy is expected to show great potential in the field of noncontact operation or actuation.