基于激光投影法的圆柱工件直径测量误差分析

Error Analysis for Diameter Measurement of Cylindrical Workpiece Based on Laser Shadow Method

针对激光光束投影法直径测量精度受多种因素影响而下降的问题,提出了一种计算圆柱体直径的解析几何方法。分别用解析几何方法和近似等腰三角形方法推导出圆柱工件直径计算公式,并进行了圆柱工件直径测量仿真,分析了激光源位置、被测工件位置、线阵CCD分辨率和被测工件直径等参数对直径测量结果的影响。结果表明,在激光源位置、工件位置和工件直径变化时,提出的解析几何方法仍能够保证直径测量的准确性,其测量误差只与线阵CCD传感器的分辨率有关;提高CCD传感器的分辨率,可以提升圆柱工件直径的测量精度。采用解析几何方法和高分辨率的线阵CCD可满足激光直径测量系统高精度的应用要求。

Aiming at the problem that the accuracy of diameter measurement by laser beam shadow method is degraded due to various factors, an analytical geometric method for calculating cylindrical diameter is proposed.The formulas for calculating the diameter of cylindrical workpiece by the analytical geometric method and approximate isosceles triangle method are derived respectively, and the simulation for diameter measurement of cylindrical workpiece is carried out.The effects of the position of laser source, the position of measured workpiece, the resolution of linear CCD and the diameter of measured workpiece on the results of diameter measurement are analyzed.The results show that the proposed analytical geometry method can still maintain the accuracy of diameter measurement as the position of laser source, the position of workpiece and the diameter of workpiece are changed.Meanwhile, the measurement error for diameter measurement by means of the analytical geometry method is only related to the resolution of the linear array CCD sensor.The measurement accuracy of cylindrical workpiece diameter could be improved by increasing the resolution of the CCD sensor.Using the analytical geometry method and high-resolution-rate linear array CCD can meet the requirements of laser diameter measurement systems for high-precision applications.