激光光束对光幕测速系统的影响

Impact of the Laser Beam on Light Screen Velocity Measuring System

在高精度速度测量系统中,激光光束截面形状以及光强分布影响测量结果,基于激光光束的高斯模型,计算出关于出射轴线对称的规则和非对称激光束光强变化率随位置变化的曲线,推导出设置阈值电压的最佳位置,并计算出在最佳位置处设定比较阈值对光幕测速系统的影响,提出在激光光束前添加狭缝压缩光束宽度的方法,相对距离误差减小为0.003 8%,误差减小了61.2%.

In the high-precision laser-based velocity measuring system, the section shape and light distribution of laser beam has great impact on the final result. Based on the Gauss model of laser beam, we calculate the curve of light intensity varying in different position as well as the optimum position to set the threshold voltage to axis-symmetric and nonaxis-symmetric laser. In addition, we also analyze the system error in the optimum position and develop a method of adding a slit before the laser beam to cut down beam width, which reduce system error to 0. 003 8%, 61.2% less comparing to the system without a slit.