双光束激光多普勒转速测量系统的实验验证

Experimental Verification of Dual Beam Laser Doppler Speed Measurement System

激光多普勒测速技术具有非接触、无磨损、精度高等优点,被广泛应用于工业、航海、航天等领域的高精度速度、加速度、长度测量。双光束激光多普勒测速技术作为其中的一个分支,具有结构简单、抗干扰强的特点。为提升双光束激光多普勒测速技术的测量精度,搭建一种测量圆周转动线速度的轴对称型双光束激光多普勒系统,采用高速响应的探测器观测差频信号。当目标的线速度为1 596.6 mm/s时,激光多普勒差频信号理论值是0.975 MHz,测量角度为0°,实验观测到的差频信号是1.013 MHz,与理论值相比误差约为3.8%;进而变换观测器的不同角度位置,测量得到的多普勒频移和0°的频移误差在0.8%以内。结果表明,该测量系统能够测量到运动物体的多普勒频移信号,同时更改双光束激光多普勒测速的观测器角度,不影响测量结果。该实验系统为后续进一步进行激光多普勒测速技术的研发打下了良好的基础。

Laser Doppler velocimetry technology has the advantages of non-contact, wear-free and high precision. It is widely used in high-precision velocity, acceleration and length measurement in industry, navigation, aerospace and other fields. Dual beam laser Doppler velocimetry has the characteristics of simple structure and strong anti-interference. In order to improve the measurement accuracy of dual beam laser Doppler velocimetry, this paper introduces a double beam laser Doppler system for measuring the linear velocity of circular rotation. When the linear velocity of the target is 1 596.6 mm/s, the theoretical value of laser Doppler difference frequency signal is 0.975 MHz. The measurement angle is 0°, and the difference frequency signal observed in the experiment is 1.013 MHz, with an error of about 3.8%. Furthermore, by changing the different angular positions of the observer, the measured Doppler frequency shift and 0° frequency shift error are within 0.8%. Results show that the measurement system can measure the Doppler frequency shift signal of moving objects and change the observer angle of dual beam laser Doppler velocimetry without affecting the measurement results. This experiment provides a useful reference for the development of this kind of sensor.