Study On The Design Method , Drive And Control System Of The Traveling Wave Type Motor

Traveling wave revolving ultrasonic motor is the direct driver motor that transforms electric energy to mechanic energy by means of the converse piezoelectric effect of piezoelectric ceramic and friction drive.Because of its many characteristics, such as high power density, low velocity and large torque, quick response, good control performance, self-locking without electricity, insulation with magnetic field , which makes it useful in many fields. But a lot of theory problems about its performance have not been resolved and systematic design theory and method have not been established. And in the practical work, the temperature of the stator will be increased along with the long time drive by power, the frequency will be shifted. At present, the main problem is the low output efficiency of the drive power. Many factors affect the control model of the motor, the problem will be more complex when taking many factors into account. It will hinder its application in many fields. The control system of the ultrasonic motor is discussed in this paper. In order to drive motor steadily, the driving circuit needs to have the capacity of frequency tracking automatically. The characteristic of frequency modulation has slowly start-up and finite area of modulate frequency; phase modulation has low response and precision.Based on these analyses, the method applied in this paper combines frequency modulation and phase modulation together. It has many characteristics of quick response ,simple control system and high modulating precision.1. The natural vibration of the circular thin plate is discussed, theoretic expression of natural frequency is gained, the effect of friction material on motor performance is analyzed ,present the criterion of friction material.2. A two-dimension elastic contact model is used for establishing the friction drivebetween the rotor and the stator of the motor. An electrical equivalent circuit is used to estimate the interaction between the electrical and mechanical parts of the stator. A new design method is presented.3. The velocity modulating method that combines frequency modulation and phase modulation is applied, frequency modulation is the main method, when large modulation range is needed, it can change into phase modulation. The central unit of the whole system is 8051, multi-periphery interact CMOS chip are used as supplementary.4. Linearity power and switch power are analyzed and compared; the power project and the circuit of drive power applied in this system have been given.5. The designed motor is analyzed by ANSYS, and the experiment for test motor performance is designed, the effect of piezoelectric ceramic on the stator of the motor is analyzed and the conclusion that the effect of piezoelectric ceramic on the stator of the motor is less is gained, the simulation results are in good agreement with the theoretical calculation results.In this paper, models of traveling wave revolving ultrasonic motor are given. On the basis of the models, a method of design for a traveling wave type ultrasonic motor is established; the control method applied in this system can drive and control motor function steadily, this design method is different from the previous design methods. The proposed method is applied to the design of a prototype motor.