Simulation and Experimental Study on Application of Relaxor Ferroelectric Single Crystals to Ultrasonic Motor

The relaxor ferroelectric single crystals have become an ideal substitute materials for improving the performance of ultrasonic motor as their excellent piezoelectric performance and cryogenic property. But the amplitude uniformity of stator and the interference of vibrations have to be considered in the process of single crystal ultrasonic motor design due to the anisotropy of single crystals. The operating frequency, amplitude and amplitude uniformity of stator are analyzed through the calculation and the finite element analysis of the piezoelectric, dielectric and elastic performance of two cutting orientations with amplitude uniformity. A prototype of single crystal ultrasonic motor is designed and fabricated. The results show that the proposed single crystal ultrasonic motor with Ø20 mm has a locked-rotor torque of 0.057 N·m, which is better than that of the piezoelectric ceramic ultrasonic motor with the same diameter.