用激光外差技术高精度测量目标速度

High precise measurement of target velocity using laser heterodyne technology

搭建了外差探测实验平台,分别选用漫反射目标及类简谐运动模型作匀转速运动及变速运动的测量目标,应用激光外差探测技术实现了对匀转速运动及变速运动物体的速度测量。在匀转速测量过程中,同时采用外差探测法和振幅调制法测量了漫反射目标正负两个方向转动的速度,共得到133组不同的转速结果。通过调整实验系统,亦实现了对类简谐运动目标的变速测量,应用Matlab数学工具对拍摄频谱视频做后续处理,得到了运动目标的实时速度。测试结果显示,在0.05～16m/s测量匀转速时,正向转动平均相对误差为0.51%,负向转动平均相对误差为0.42%;另外,变速测量的正负最大速度分别为0.555 6m/s和-0.659m/s。结果证明了激光外差对速度测量的高精度性,实验中频谱峰值清晰可见,说明激光外差探测具有较高信噪比。

A heterodyne detection experiment is established to measure the constant rotation velocity and the variable velocity of targets,in which the diffuse reflectance target and simple harmonic motion model are taken as research targets.For uniform rotation velocity measurement,the heterodyne method and amplitude modulation velocity measurement are conducted at the same time to measure the rotation velocity of a diffusion target in two directions and 133 sets of results are obtained.Moreover,the variable velocity is measured for a target with like-harmonic motion by the same optical system,and the spectrum video is processed by the Matlab software to get the velocity.Tested results show that,in the uniform rotation velocity range from 0.05 to 16 m/s,the average relative error for positive and negative rotation analytical measurements are only 0.51% and 0.42%,respectively.In a variable velocity measurement for positive and negative rotations,the maximum speed are 0.555 6 and-0.659 m/s,respectively.The results indicate that the measurement has a higher accuracy and a higher Signal to Noise Ratio（SNR） for a clear mid-frequency spectrum can be seen.