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为了提高测量微小振动的精度和动态范围 ,提出一种基于激光光栅多普勒效应的微振动测量系统。通过对差拍信号的频率分析 ,以峰值频率比值的方法可以排除干扰获得被测振动频率 ,找到振动的翻转点并判断振幅的大小 ;推导了在翻转点附近的微小位移与电压值的关系 ,对于小于计数当量值的位移由测量电压得到 ,提高了微小振动位移的测量精度以及系统测量的最小分辨率、动态范围。实验系统的频率范围为 0 .5～ 5 0 0Hz,振幅为2 0～ 10mm ,相对误差小于 1% ,其动态范围大于 10 0dB。
In order to improve the precision and dynamic range of measuring tiny vibration, a micro vibration measurement system based on the laser grating Doppler effect is proposed. Through the frequency analysis of the beat signal, the method of peak frequency ratio can eliminate the interference to obtain the measured vibration frequency, find the flip point of vibration and judge the amplitude. The relationship between the small displacement and the voltage value is deduced, For less than the equivalent value of the displacement measured by the voltage obtained, improve the measurement accuracy of small vibration displacement and the system to measure the minimum resolution, dynamic range. The experimental system has a frequency range of 0.5-500 Hz, an amplitude of 20-10 mm, and a relative error of less than 1% with a dynamic range greater than 10 0 dB.