为了解决高精度数控装备对位移传感器高分辨力反馈的需求,本文提出通过对空域信号特征的分析,从时空变换理论模型的角度去研究位移测量问题;利用光栅周期性栅线作为等空间位置触发位置采样建立空间序列模型;通过对光栅莫尔条纹信号自适应预测细分模型阶数与系数估计算法完成光栅莫尔条纹信号细分。实验结果证明此方法可以实现光栅莫尔条纹400倍细分,细分精度优于信号周期的±1%。此细分方法利用光栅刻划精度,信号细分精度与光栅信号波形质量无关,在不增加硬件的条件下实现光栅莫尔条纹精密细分,具有重要实际应用价值。
In order to meet the high resolution feedback requirement of displacement sensors for high precision numerical control equipment,the displacement measurement problem is studied using time-space transformation theoretical model based on signal feature analysis in space domain. The space series model is built using the periodic grating lines as the trigger signals of equal spatial position sampling. The order and coefficients of self-adaptive forecast interpolating model of the grating Moire fringe signal are estimated,which is used to achieve the Moire fringe interpolation of optical grating sensor. Experiment results show that with the proposed method,the maximum interpolation number of 400 can be achieved for the grating Moire fringe,and the interpolation precision is better than ± 1% of the signal period. The proposed method makes use of the most manufacturing precision of optical grating,and the interpolating precision is independent of the signal waveform quality of optical grating. The grating Moire fringe interpolation is implemented without increasing any hardware,which has an important practical value.