基于坐标旋转数字计算算法的小型光电编码器细分  

Interpolation of Small Photoelectric Encoder Based on Coordinate Rotation Digital Computer Algorithm

作　　者：冯英翘[1,2] 万秋华[1] 宋超[1,2] 孙莹[1] 赵长海[1] 

机构地区：[1]中国科学院长春光学精密机械与物理研究所,吉林长春130033 [2]中国科学院大学,北京100049

出　　处：《光学学报》2014年第2期26-31,共6页Acta Optica Sinica

基　　金：中国科学院知识创新领域前沿项目

摘　　要：为在不增加体积的前提下提高小型光电编码器精度,分析了计算法细分误差产生的原因,提出了基于坐标旋转数字计算(CORDIC)算法的光电编码器精码信号新细分法,利用简单的移位和加法操作可实现对采集到的正交码盘精码信号直接细分求相位,避免了查"细分表"引入的细分误差。对细分算法进行了分析与优化,使算法在取得合适精度的同时提高了运算速度。运用研究的细分法对某16位小型光电编码器精码信号进行256份细分时,比利用计算法细分时编码器的均方根误差减小了一半。实验结果表明,研究的新细分法可直接对光电编码器精码信号进行高精度细分,对于研制小型化、高精度光电编码器具有重要意义。To improve the accuracy of small photoelectric encoders without increasing the size, the reason how interpolation errors are generated by the calculation method is analyzed. A new photoelectric encoder fine signals interpolation method based on coordinate rotation digital computer （CORDIC） algorithm is proposed, and it can make use of simple shifting and addition operations to directly interpolate acquired quadrature fine signals and resolve the phases, which can get rid of interpolation errors caused by looking up in the interpolation table. The algorithm is analyzed and improved finally, and the calculation speed is proved while maintaining appropriate accuracy. Moire fringe signals from a 16-bit small photoelectric encoder are interpolated into 256 parts with the suggested algorithm, and the root mean square error is decreased by a half compared to the calculation method. Experimental result shows that the new interpolation method can be directly applied to high-accuracy interpolation of moire fringe signals. It may play an important role in the further research and development of small and high-accuracy photoelectric encoders.

关 键 词：光栅 光电编码器 细分误差 坐标旋转数字计算算法 精度 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]