表面散射光对激光三角法位移测量的影响

三角测量法是一种位移测量方法, 其测量精度不但受到传感器本身因素如光源、探测器、机械结构特性等因素的影响, 还受到被测表面特性如色泽、材料、粗糙度、倾斜度以及外界环境的影响。国内外的一些学者提出了许多提高传感器测量精度的方法, 但这些研究都是针对某一特性表面进行的, 没有涉及到对不同表面的测量时存在的问题。利用随机行走理论对物体表面的散射场进行了分析, 给出了不同粗糙度表面下弱散射光强与散射角及入射角的关系。由于设计制造的传感器量程范围内接收散射光的角度在15°至25°内变化, 因此取20°作为散射角角度, 理论计算模拟的三种不同粗糙面散射光强变化最大能达到300%左右。该结果对于优化激光三角传感器的设计和提高测量精度有一定的意义。

The Influence of Surface Scattered Light to the Measurement of Laser Displacement Sensor Based on Triangulation

The accuracy of laser displacement measurement based on triangulation is affected not only by optical source, detector and mechanical construction, but also have relation with measured surface features such as luster, material, roughness, inclination and environment. Some researchers have presented some methods to improve the measurement accuracy, which based on the same surface features. In this paper the scattered light field on the measured surface is analyzed with random walk theory. The relations of scattered light intensity and scattered light detected angle on different roughness surface are shown. Because the scattered light detected angle of sensor we made is between the 15°to 25°, the value of scattered light angle is assumed to be 20°, the maximum change of scattered light intensity on three different roughness surface is roughly 300% through the simulation. These model and results are helpful to the optimal design of the laser displacement sensor and improvement of measurement accuracy.