Research on the vibration characteristics of cylindrical type ultrasonic motor using longitudinal vibration transducers

In a previous research,the authors have presented and developed a cylindrical type ultrasonic motor using longitudinal vibration transducers.Four uniform longitudinal vibration transducers are adopted in this motor to excite a bending vibration traveling wave in a cylinder with teeth.The simulation and experiment results of this motor indicate that the vibration state of the transducer is not single longitudinal vibration,but longitudinal and bending coupled vibration.This study focuses the research on the vibration state of the transducer in the previous motor.Firstly,the reason for the bending vibration of the transducer is given.Then,the effect of the coupling bending vibration on the electromechanical coupling factor of the motor and the distortion of traveling wave are studied.The study results state that the coupling bending vibration of the transducer can make the resonance frequency of the stator deviate from the resonance of the transducer and cause a distortion of traveling wave in the cylinder.Finally,new mode to excite the radial bending vibration of a cylinder by using the bending vibration of a transducer is presented.