Coupled Dynamics for Noncontact Piezoelectric Motor Modulated by Electromagnetic Force

A coupled dynamics model for a noncontact piezo-electric motor modulated by electromagnetic force is presented in this paper. Coupled dynamic equations of the motor system are derived. From the equations, the natural frequency, and modal function equations of the motor system are provided. Considering the nonlinear constitutive relation of a piezo-electric stack, nonlinear coupled dynamic equations of the motor system are established, and the nonlinear vibration frequency equation of the motor system is obtained. The linear and nonlinear coupled natural frequencies, modal shapes, and forced responses of the motor system are studied using the obtained equations. Modal shapes of the motor system are then classified, and the deviation between the nonlinear vibration frequency and linear natural frequency of the motor system and its variation with system parameters are analyzed. The research provides a useful reference for design and analysis of the dynamic behavior of the motor system.