Design and analysis of a cylindrical standing wave ultrasonic motor using cantilever and sandwich type transducers

A cylindrical standing wave ultrasonic motor using cantilever and sandwich type transducers was proposed in this paper. There are four pairs of cantilevers outside the cylindrical stator, and four PZT ceramics are set between each pair of cantilevers. The PZT ceramics together with a pair of cantilevers compose a longitudinal transducer. The bending mode of cylindrical stator is excited by the longitudinal vibration of PZT ceramics. Thus, linear simple harmonic motions are achieved at the particle on the teeth. And the frictional force between rotor and stator is the driving force to realize the rotational motion of rotor. The PZT ceramics work with d₃₃ mode, which have high electromechanical coupling efficiency and could improve the output characteristics. The working principle of proposed motor was analyzed. The cylinder and longitudinal transducer were designed with FEM. The sensitive parameters of resonant frequency of transducers and cylinder were gained with modal analysis. The longitudinal resonant frequency of transducers and bending resonant frequency of cylinder were degenerated, and the motion trajectories of nodes on the teeth were analyzed. The results of this study could be useful in the development of this new type of ultrasonic motor.