激光位移传感器在自由曲面测量中的应用

以点激光位移传感器(HL-C211BE)为对象,研究它在自由曲面测量中的应用。针对激光位移传感器因测点倾角代入的测量误差,提出了一个可以量化的倾角误差模型。基于直射式点激光三角法原理,分析了激光光路的几何关系,从会聚光斑光能质心发生的偏移推导出倾角误差模型。随后,用高精度激光干涉仪和正弦规对激光位移传感器进行校对实验,并用误差模型对测量结果进行补偿。结果显示,补偿后激光位移传感器的测量精度得到明显提高。对一非球面凸透镜进行了实验测量,得到了自由曲面测点倾角的计算方法,并用倾角误差模型修正了测量数据。实验结果表明,量化的倾角误差模型可以将激光位移传感器的测量误差控制到小于10μm,满足激光位移传感器在自由曲面测量中应用的要求。

Application of laser displacement sensor to free-form surface measurement

By taking a point displacement laser as an object, this paper researches the application of the sensor to free-form surface measurement. In consideration of the measurement error of the laser displacement sensor due to the inclination of the measuring point, a quantifiable inclination error model was proposed to improve the measuring accuracy. On the basis of the principle of direct-point laser triangulation start, the geometric relationship of the laser light paths was analyzed. According to the shift of convergent light spot centroid, the inclination error model was derived. Following that, the laser displacement sensor was calibrated with a high precision laser interferometer and a sine bar, the measured data by the laser displacement sensor were compensated by the error model, and the measurement accuracy was significantly improved. Finally, the experimental measurement on an aspheric lens surface was performed, the free-form surface inclination measuring point was calculated and the measurement data were corrected by the proposed model. Experimental results show that inclination quantization error model has controlled the measurement error of the laser displacement sensor by less than 10 μm, which meets the requirements of the free surface measurements by laser displacement sensors.