Design and experimental research on a deep-sea resonant linear ultrasonic motor

A deep-sea linear ultrasonic motor, which takes in-plane expansion mode as the working mode, is proposed in this paper. Its main structure is rectangular metal plate with four piezoelectric ceramics. First, suitable structural parameters of the ultrasonic motor are obtained by finite-element simulation. Then, the influences of static seal and the pressures of water on the performance of the ultrasonic motor are studied. Simulation result shows that the static seal slightly degrades the resonant frequency of the ultrasonic motor and vibration amplitude of the driving foot, and the pressures of water almost have no effect on resonant frequency, but it reduces the performance of the ultrasonic motor. Finally, we design and manufacture the prototype, whose velocity is measured at 214 mm/s while the water pressure is 8 MPa and the voltage signal with a frequency of 72 kHz and a voltage magnitude of 200 V. The experimental indicates that simulation results are consistent with experimental results. We verify the feasibility of the ultrasonic motor working in the deep-sea environment.