基于VMD的圆光栅测角误差补偿方法

Compensation Method of Circular Grating Angle Measurement Error Based on VMD

针对圆光栅测角系统误差数据,提出了一种基于变分模态分解(VMD)的误差重构与补偿方法。首先,采用VMD算法将误差数据自适应地分解为多个模态分量(IMF),基于各IMF的相关因子值表征其含噪声程度,选择符合条件的IMF重构系统误差,再溯源分析系统误差的主要谐波阶次,建立误差补偿模型。实验结果表明:利用此方法可将圆光栅测角误差的平均值、峰峰值和标准差分别补偿至-0.029″(补偿百分比:90.73%)、1.14″(补偿百分比:51.07%)和0.29″(补偿百分比:57.35%),加入随机误差后也能准确识别误差主要成分。

An error reconstruction and compensation method based on variational modal decomposition(VMD)was proposed for the error data of the angle measurement system of angle grating.First,the VMD was used to adaptively decompose the error data into several intrinsic mode functions(IMF),characterized the degree of noise content based on the correlation factor value of each IMF,selected the eligible IMF to reconstruct the system error,and then traced back to analyze the main harmonic orders of the system error to establish the error compensation model.The experimental results show that the mean,peak-to-peak and standard deviation of the angle measurement error of the angle encoder can be compensated to-0.029″(compensation percentage is 90.73%),1.14″(compensation percentage is 51.07%)and 0.29″(compensation percentage is 57.35%)by this method,the main components of the error can be correctly identified even after adding random errors.