光电轴角编码器光电信号正交性偏差的相量校正方法

高精度光电轴角编码器中的细分是误差的主要来源,而细分误差中莫尔条纹光电信号的正交性偏差影响最大。采用相量校正方法对正交性偏差进行校正,实现电路简单,校正效果十分明显。以正弦信号为基准信号,而将余弦信号分解为0°和90°两个正交分量,0°分量就是产生正交性误差的原因,通过补偿掉该分量,即可基本消除正交性误差。为进一步减小细分误差,通过精密调节,使余弦信号的幅值与正弦信号严格相等,将正弦及其反相信号与余弦信号分别相量相加可得到严格正交的两个新相量,从而消除正交性误差。实验结果表明,经精密相位校正后,正交性偏差从1″降低到0.1″左右。

Phase correction of quartering deviation of photoelectric rotary encoder

The error of photoelectric rotary encoder mainly comes from interpolation. The quartering deviation of Moiré fringe of a rotary encoder is the most important part in interpolation error. The two methods of precise phase correcting are designed. Those correcting circuits are simple and efficient. The sine signal of encoder is regarded as phase reference(0°) ,the cosine signal can be separated into 0°and 90° vectors .The quartering deviation is created by 0° vector mainly. In this paper,the cosine signal is quartered to sine signal through compensating the 0° vector of cosine to reduce the quartering deviation. If the lower error is needed, the two signals, sine signal and inverting signal of sine, and cosine signal can be created, then the two signals can become quartering seriously though adjusting the value of cosine equal to sine signal. The experimental results show that the interpolation error is reduced from 1″ to 0.1″ after the precise phase correction.