光栅角编码器偏心误差修正方法研究

Study on Eccentricity Error Correction Method for Optical Angular Encoder

为了减小光栅角编码器偏心误差的影响,提高光栅角编码器角度测量的精度,对偏心误差的修正方法进行了研究。通过对光栅角编码器测角原理和偏心误差产生原因的分析,建立了偏心误差模型。并根据偏心误差模型的特点,对其进行简化,得到易于数学计算的偏心误差修正模型。以平行光管和23面棱体为基准,得到存在偏心误差的一组光栅角编码器测量数据。使用线性最小二乘参数选择准则,对偏心误差修正模型中的参数进行优化计算,得到修正模型中的参数,完成对光栅角编码器误差偏心的修正。通过误差修正试验和精度验证试验,表明经过偏心误差修正,系统测量精度优于±13″。修正方法达到了补偿误差的目的,提高了光栅角编码器的测量精度,满足了高精度角度测量的要求。

In order to reduce the eccentricity error,as well as improve the measurement accuracy of the optical angular encoder,the error correction method was studied.An eccentricity error mathematic model was built up based on the measurement principle of the optical angular encoder and error analysis.Then the model was simplified considering its characteristics,and a modified error correction model was obtained which was less complex in calculation.With a collimator and a 23 polyhedron as measuring datum,a set of optical angular encoder measuring data,which containing the eccentricity error,was obtained.Considering the optimization calculation of the overdetermined equation,linear least-squares were used to get the optimum estimation results and the eccentricity error was corrected with the estimation result.In the experiment,correction model of the optical angular encoder was obtained.A measurement with the error corrected optical angular encoder was taken out as well to test the measurement accuracy of the model.Error correction and accuracy verification tests were made,and the result showed that the accuracy of the error corrected optical angular encoder measurement system is higher than ±13″.The eccentricity error correction method reduces the eccentricity error of the optical angular encoder,and improves the measurement accuracy.