Research On Data Processing And Application Of Laser Doppler Vibration Measurement

The vibration of an object often reflects a certain characteristic of the obj ect itself.In order to obtain the vibration characteristic of the object,it is necessary to measure the vibration accurately.The traditional contact vibration measurement method is invasive,which will change the original vibration shape of the object and affect the measuring accuracy.Compared with the traditional contact vibration measurement,the laser Doppler measurement method has the advantages of high measurement accuracy,fast response time,high spatial resolution,non-contact measurement and so on,a nd has been applied more and more widely in engineering.This dissertation summarizes the basic theory of laser Doppler vibration measurement technology,the present research situation and the development trend at home and abroad.A differential Doppler measurement system is designed for in-plane vibration measurement.The system includes photoelectric conversion module,preprocessing circuit and signal processing module.In order to improve the measurement accuracy of the system,the wavelet and Kalman filter are proposed to denoising the measured data.A new wavelet denoising threshold algorithm is designed.The effect of wavelet filtering and Calman filtering on denoising is compared.The results show that the denoising effect of Kalman filter is better.Finally,the error in the experiment is analyzed.In order to verify the performance of differential Doppler vibration measuring system and the feasibility of motor speed measurement,the vibration measuring system is applied to measure motor speed.The experimental results show that the vibration measuring system can measure motor speed effectively.The data of two algorithms after denoising show that root-mean-square value of Kalman filter is closer to the rated speed value,the variance is sma ller,the relative error is smaller,and the denoising effect is better.