基于反正切法细分的光栅编码器设计

Design of Grating Encoder Based on Arctangent Subdivision

介绍了一种数字处理技术实现对光栅编码器所产生莫尔条纹信号的细分。莫尔信号经过光电转换后输出两路正余弦信号并通过光栅解码电路对其AD(analog to digital)采样,利用正切值消除正余弦信号的非线性误差,根据正余弦信号的正负将一个周期信号分割成8份,通过反正切角度值实现对每一份的细分。最后将此设计应用于单轴转台。实验结果表明,光栅编码器输出的的静态位置精度可以达到0.000 1°,动态位置及速度曲线无跳变,满足使用要求。

A digital processing technique to realize the subdivision of stripe signals generated by a grating encoder is introduced.After photoelectric conversion,the Moore signal output two positive cosine signals and the analog to digital(AD)sampling through the raster decoding circuit,which uses the tangent value to eliminate nonlinear error of the cosine signal,a periodic signal is divided into eight parts according to the positive and negative of the cosine signal,and then the subdivision of each signal is realized through the arctangent angle value.Finally,the design is applied to a single-axis turntable,experimental results show that the static position accuracy of the grating encoder can reach 0.0001°,the dynamic position and speed curve have no jump,which can meet the application requirements.