非均匀采样莫尔条纹信号的分析与处理  

Analysis and processing of Moriéfringe signals based on non-uniform sampling

作　　者：左洋[1,2] 龙科慧[1] 刘金国[1] 刘兵[1,2] 周磊[1] 乔克[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,北京100039

出　　处：《光学精密工程》2015年第4期1146-1152,共7页Optics and Precision Engineering

基　　金：国家自然科学基金资助项目(No.61108066)

摘　　要：为了动态、实时地测量光电编码器在变速转动情况下的细分误差,提出了一种莫尔条纹信号的非均匀采样分析与处理方法。利用傅里叶级数原理构造了实际情况下的莫尔条纹信号方程,根据编码器在不同转速下的实时采样,揭示了莫尔条纹信号的非均匀采样特征。鉴于信号采样的非均匀性,采用曲线拟合的最小二乘法重构莫尔条纹信号,利用离散傅里叶变换算法分析重构信号并求出波形参数。通过信号参数与细分误差的关系式,测量了编码器动态细分误差。采用该方法对21位绝对式光电编码器莫尔条纹信号进行了分析和处理,两次测试得到其动态细分极值误差为+3.21″、-4.69″和+3.45″、-4.81″。实验结果表明,该方法可以有效地分析和处理编码器在非匀速转动下产生的变频莫尔条纹信号,精确地测量编码器的动态细分误差,为工作现场编码器误差的实时检测与修正奠定了基础。To measure the dynamic real-time interpolation error of an optical encoder in non-uniform rotation,a method for analysis and processing the Moriéfringe signals based on non-uniform sampling was presented.The real Moriéfringe signal equation was constructed by Fourier series principle.According to real-time sampling on the encoder at different speeds,the characteristics of non-uniform sampling for Moirésignals was revealed.On the basis of the non-uniformity of the signal sampling,the Moriéfringe signals were reconstructed by using the least square curve fitting.Reconstructed signals were analysed by Discrete Fourier Transform algorithm and the waveform parameters were obtained.With the relationship between interpolation error and signal parameters,the measurement of encoder dynamic error was achieved.The Moiréfringe signal of a 21 bit absolute optical encoderwas analysed and processed and the twice extreme dynamic interpolation errors are＋3.21 ＂;-4.69＂ and ＋3.45 ＂;-4.81＂,respectively.Experiment result shows that this method effectively processes Moriéfringe signal of variable frequency in the encoder with non-uniform rotation,and accurately measures the dynamic interpolation error of the encoder,which provides foundation for real-time detection and correction of encoder error at the actual work site.

关 键 词：光电编码器 细分误差 莫尔条纹 非均匀采样 离散傅里叶变换 

分 类 号：TP212.12[自动化与计算机技术—检测技术与自动化装置] TN762[自动化与计算机技术—控制科学与工程]