Rotation angle analyses of plate ultrasonic motor under dual-mode coupling drive

Speed improvements of plate ultrasonic motors could be achieved by choosing suitable excitation frequencies; however, the combination of these two frequencies is hard to be determined. Based on the linear superposition of vibrations at two independent mode frequencies, the rotation angles and amplitudes of modal vibrations are proposed to select the possible dual-frequency excitation combinations in this paper. Experimental prototype is a plate ultrasonic motor using single-phase asymmetric excitation, which can work under a single vibration or multiple vibration modes. The speed characteristics of prototype driven by dual-mode coupling are used to verify the coupling effects of dual-mode drive, in which each rotation angle of two modal vibrations is not close to vertical phase, and the two modal vibrations with larger amplitudes and closer rotation angles could improve the rotation speed of motor.