Design and Analysis of a Linear Ultrasonic Motor with Composite Bending and Torsional Vibration Modes

A new type linear ultrasonic motor using Second-order bending and First-order torsional modes (2B-1T) is proposed. The ultrasonic motor has two driving feet and the continuous linear motions of sliders are realized by the frictional force between stator and sliders. In this new design, bending vibration is excited by d33 mode, which controls the preload pressure, and torsional vibration is excited by d15 mode, which generates the driving force. The elliptical trajectories of both feet are achieved, when the phase difference of the two modes is 90° in time and space. The working principle of ultrasonic motor using 2B-1T is simulated. A parametric model of the stator is designed. The sensitive analyses of structural parameters are gained with modal analysis. The characteristics and trajectories of driver feet are studied by transient analysis. These results can provide theoretical basis for the development of this new type ultrasonic motor.