Waveform of driving pulse train to prevent metallic sound of ultrasonic motors

This paper describes the relationship between the shape of the pulse train and the transient vibration of an ultrasonic motor to prevent the growth of sound when the motor is driven in a stepping manner. Considering the two resonance modes of the motor, the equivalent electrical circuit is derived to analyze the transient vibration. Simulation with three kinds of pulse trains proved that the modification of the driving pulse train is effective for preventing the growth of metallic sound generated when the motor is intermittently driven.