Application of 2-D Position Sensitive Detector in Spatial Straightness Measurement of Guide Rails

摘要

A laser collimating system based on 2-D position sensitive detector ( PSD) is presented in this paper. The working principle of PSD is depicted in detail. A calibration device was developed to check the nonlinearity errors of PSD and a multilayer feedforward neural network based on error back-propagation algorithm was used to compensate errors. With the aid of computer-based data acquisition system, an automatic dynamic measuring process was realized. A series of experiments, including comparison tests with laser interferometer, were done to evaluate the performance of the measuring system. The experimental results show that the spatial straightness errors of guide rails can be measured with high accuracy. The maximum differences between the device and laser interferometer are 0.027 mm in Ydirection, and 0.053 mm in X direction in the measuring distance of 6 m.