基于光栅滤波效应的测速方法研究

Study on velocity measurement method based on grating filter effect

本文研究了一种基于光栅滤波效应的固体表面测速方法,进行了理论分析和实验验证。阐述了光栅滤波测速方法的基本原理,测试系统的基本结构,给出了具体的实验数据和测试精度等关键指标,并讨论了光栅结构参数对测速结果的影响。分别选用0.2mm和0.5mm的等距透射光栅进行光栅透过率功率谱密度函数的数值模拟计算,结果可得到不同的中心频率,验证了此方法的可行性。实验中,选用0.2mm的光栅,调整光学系统至最佳,改变被测物体的运动速度,经光栅滤波效应后会产生0.65kHz至3.23kHz的电信号,基于此信号可计算出物体的速度为0.5m/s至2.5m/s,测量精度在3.5%左右。

In this paper,a method of solid surface velocity measurement based on grating filtering effect is studied.Theoretical analysis and experimental verification are carried out. The basic principle of grating filtering and velocity measuring method,the basic structure of the testing system,the specific experimental data and the testing accuracy are given,the influence of grating structure parameters on velocity measurement results is also discussed. The transmission grating of 0. 2 mm and 0. 5 mm is used to calculate the grating transmissivity and power spectral density function. The results can be different center frequencies,which verifies the feasibility of this method. In the experiment,the selection of 0. 2 mm grating adjusts optical system to the best,changes the speed of the object to be measured,and will produce 0. 5 kHz to 3. 5 kHz signal through grating filtering effect. Based on this signal,the speed of the object can be calculated from 0. 5 m/s to 2. 5 m/s,and the measurement accuracy is about 3. 5%.