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为提高小型光电编码器精度,研究了一种精码莫尔条纹光电信号细分误差修正方法。建立单路信号波形参数方程,对采样信号进行傅里叶变换求出波形参数,利用多倍角公式将信号波形中的高次谐波分量变换为高阶分量,通过牛顿迭代法将莫尔条纹光电信号修正至标准正余弦信号;建立正弦、余弦两路信号的相位误差修正模型,利用最小二乘拟合法求解出相位误差修正参数,实现对莫尔条纹光电信号正交性误差的修正。采用该方法对某16位小型光电编码器细分误差进行修正处理,经测试细分误差峰峰值由修正前的162.5″减小到修正后的47.5″。实验结果表明,研究的误差修正方法可以有效地减小细分误差,提高精度,对于研制小型化、高精度光电编码器具有重要意义。
In order to improve the precision of the small optical encoder, a method of correcting the error of the subdivision error of the moiré fringe optical signal is studied. The single-channel signal waveform parameter equation is established. The Fourier transform of the sampled signal is used to obtain the waveform parameters. The high-order harmonic components in the signal waveform are transformed into high-order components by the multi-angle formula. The moire fringe photoelectric The signal is modified to the standard sine and cosine signals. The phase error correction model of sine and cosine signals is established. The phase error correction parameters are solved by the least square fitting method to correct the error of the orthogonality of moire fringe photoelectric signals. This method is used to correct the subdivision error of a 16-bit small optical encoder, and the peak-to-peak error of the subdivision test is reduced from 162.5 “before correction to 47.5” after correction. The experimental results show that the error correction method can effectively reduce the subdivision error and improve the accuracy, which is of great significance for the development of miniature and high precision optical encoder.