The Development Of The Optical Chopper Based On Ultrasonic Motor

Ultrasonic motor is a kind of device which makes use of the conversepiezoelectric effect to produce the movement of stator，and drive the rotor by frictionbetween the stator and rotor. It has many outstanding features such as low speed andhigh torque，rapid response，large holding torque，small size and light weight，lessnoisy and no electromagnetic disturbance，etc. Optical chopper designed based onultrasonic motor has many advantages compared with the traditional optical chopper.In this paper，a type of ultrasonic motor which is used as the drive part of opticalchopper has been studied. The main work is summarized as follows：Firstly，the research background and significance of the optical chopper based onultrasonic motor are summarized. The research development，classification andapplication prospect of the ultrasonic motor are introduced. A cylinder motor ispresented in this paper，in which the structure and the basic movement principles ofthis motor have been discussed.Secondly，the modal analysis, harmonic response analysis and transient analysisof piezoelectric ceramic tube were done by using ANSYS FEM software. Based on theresult of analyzing FEM model, the relationship of vibration displacement andfrequency are obtained. By the analysis of the stator with different structuralparameters，the influence factors to the eigenfrequency of the stator in differentdimension parameters such as the height，the thickness，the inner diameter，the outerdiameter，have been discussed. These analyses offer the optimum structural parametersof the stator.Finally，on the basis of theoretical research, the following contents are completed.1. The basic structure of the cylinder type ultrasonic motor is designed and anoptical chopper prototype is finally completed.2. The driving circuit of the ultrasonic motor has been completed，in whichincludes four parts：frequency signal source、frequency divider、phase shifter、power amplifier. This circuit can alter the speed of ultrasonic motor by adjustingthe driving frequency and the input voltage. 3. The performance test platform of the optical chopper has been built. Theexperimentation is carried out by which the relationship among the rotation speedof the motor and the driving frequency，input voltage and analyze the performanceof the optical chopper have been tested.