PSD空间三维非线性修正技术的研究

提出了一种长距离激光准直测量中的位置敏感探测器(PSD)空间三维非线性修正技术,研制了在三维空间内测量二维PSD非线性的自动标定系统.在长达78 m的准直测量范围内,对二维PSD的非线性特性进行了标定实验,实验结果表明,PSD与激光源距离不同时,其非线性特性具有很明显不同.利用多层前馈神经网络建立了入射光实际位置与二维PSD输出坐标以及准直距离间的空间三维映射关系,进而对PSD的空间三维非线性进行修正.非线性修正后的PSD读数误差,在整个测量范围内表现为不大于±0.012 mm的随机误差.

Study on spatial 3-D Nonlinear Correction Technique for PSD

A spatial 3-D nonlinear correction technique is put forward to correct the nonlinearity errors of the PSD in long distance laser collimating measurement. An automatic calibration system is developed to measure the nonlinearity of a 2-D PSD in 3-D space. The nonlinear characteristic of 2-D PSD is checked in a long collimating distance of 78 meters. The experirnental results show that the nonlinearity of 2-D PSD is different evidently when the PSD element is at different position from the laser head. The spatial 3-D mapping relationship between the actual displacements of the incident light and the coordinates of 2-D PSD outputs is established by using a muhilayer feedforward neural network and the nonlinear errors are corrected with this map. The readout errors of the PSD after correction are shown as random and no more than i0. 012 mm in the whole measuring distance.