Nonlinear Dynamics Analysis Of Rotating Tra Veling Wave Type Ultrasonic Motor

As a new type of motor,ultrasonic motor has a broad application prospect in some special fields,such as space exploration,precision instruments and so on,because of its unique performance,such as low speed,high torque,light weight,compact structure,high start-stop sensitivity,fast response,and no interference from external magnetic field.However,the structural characteristics of the ultrasonic motor and its working form determine that the ultrasonic motor has a strong electromechanical coupling non-linear system compared with the general mechanical vibration system,so that it tends to produce non-linear phenomena such as frequency drift,jump,and hysteresis during the working process.These characteristics seriously affect the smoothness and reliability of the operation of the ultrasonic motor.In order to improve the performance of the motor,it is necessary to conduct a certain study on the nonlinear dynamic characteristics of the motor.For this reason,this paper considers the nonlinear constitutive relationship of the stator piezoelectric material and the nonlinear factors of the stator and rotor friction contact.On the basis of dynamics model,based on the fourth-order Runge-Kutta method,the dynamic behavior of the rotating traveling-wave ultrasonic motor was analyzed and studied with the help of the Lyapunov exponent and the Poincarécross-sectional diagram.The specific research content is as follows:(1)On the basis of considering the nonlinear constitutive relationship of the piezoelectric material of the stator,the stator is analyzed based on the fourth-order Runge-Kutta method based on the nonlinear equation of the standing wave vibration of the rotating traveling wave ultrasonic motor stator under single-phase excitation.The Hopf bifurcation of the standing wave vibration response under the change of excitation parameters and the change process from the Hopf bifurcation to the periodic solution.This result has certain reference significance for the research on further improving the output characteristics of the traveling wave ultrasonic motor;(2)Based on the fourth-order Runge-Kutta method,the nonlinear dynamic behavior of the stator traveling wave vibration response under the change of excitation parameters is analyzed based on the nonlinear equation of traveling wave vibration of the stator of the rotating traveling wave ultrasonic motor under two-phase excitation.The results show that there are nonlinear phenomena such as multiple solutions and amplitude saturation in the stator vibration;(3)Considering the influence of the friction contact interface force between the stator and the rotor,the nonlinear dynamic behavior of the entire ultrasonic motor and the output characteristics of the motor were further studied to lay the foundation;(4)Analyze the whole machine model based on the numerical integration method,study the change curve of the rotor speed under different input parameters,give the output characteristic curve and load characteristic curve of the motor under different input parameters,and reveal the rotating traveling wave ultrasonic motor The nonlinear phenomenon.