新型光栅信号数字细分技术及其误差分析

A New Digital Subdividing Technique for Grating Signal and Its Error Analysis

在圆光栅作为分度基准的高精度测量仪器中 ,利用A D转换器和单片机 ,用软件编程的方法 ,对光栅读数头输出的sinθ和cosθ函数进行新的构建 ,形成一线性函数。通过对新建函数和原函数进行过零检测 ,实现莫尔条纹八细分 ,然后 ,用软件来实现对线性函数的幅度分割 ,采用查表的方式实现莫尔条纹十细分。本文还对此方法引入的误差进行了研究 ,与传统的细分法相比 ,此方法硬件电路简单 ,细分误差小 ,且便于误差修正 ,能实现高精度角度测量。

In a high precision measurement instrument using the radial grating as the graduated reference, a linear signal is generated from the sinθ and cosθ signals that are the output of the grating reader. By detecting the zero points of the generated signal and the original signals, the eight-fold subdivision for Moire fringes is carried out. Then the amplitude of the linear signal is segmented using digital computing method, and the ten-fold subdivision for Moire fringes is implemented using the LUT technique. Furthermore, the error induced by the technique is analyzed in the paper. Compared with the common subdividing techniques, it has many advantages such as simple electronic circuit, little subdividing error, and convenient for error correction. Thus high precision angle measurement is realized.