Zhao Changhai, Wan Qiuhua, Liang Lihui
Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, China.
Rev Sci Instrum. 2024 Jul 1;95(7). doi: 10.1063/5.0211297.
Eccentric error is a vital part of high-precision optical encoder error. An automatic error compensation system is designed to lower the eccentric error of the encoder. On the periphery of the fan-shaped code path of the traditional encoder disk, a set of radial code paths is drawn. This radial code path is composed of several concentric circles with alternating light and dark lines. The direction of the radial code path is perpendicular to the direction of the fine code path. When the encoder rotates, the eccentricity of the encoder disk is measured by the moiré fringe signal output from the radial code channel. Based on the eccentricity error compensation algorithm, the eccentricity error of the encoder disk is compensated in real time to enhance the accuracy of the encoder. The experimental results of an encoder show that the mean square error of the encoder before the eccentricity error compensation is 21.25 arc seconds, and it is 3.66 arc seconds after compensation by this algorithm. The algorithm can significantly compensate the error caused by the eccentricity of the encoder and greatly improve the accuracy of the encoder.
偏心误差是高精度光学编码器误差的重要组成部分。设计了一种自动误差补偿系统来降低编码器的偏心误差。在传统编码器盘的扇形编码路径周边绘制了一组径向编码路径。该径向编码路径由若干带有明暗交替线条的同心圆组成。径向编码路径的方向与精细编码路径的方向垂直。当编码器旋转时，通过径向编码通道输出的莫尔条纹信号来测量编码器盘的偏心度。基于偏心误差补偿算法，对编码器盘的偏心误差进行实时补偿，以提高编码器的精度。一个编码器的实验结果表明，偏心误差补偿前编码器的均方误差为21.25角秒，采用该算法补偿后为3.66角秒。该算法能够显著补偿编码器偏心引起的误差，大大提高编码器的精度。
