基于纳米时栅传感器安装偏差的测量精度分析研究

摘要

In order to quantify the influences on measurement precision caused by assembly parameters,the gap d0 and effective overlap area variation ΔS between the fixed ruler and the moving ruler are employed as independent variables to build mathematical models for measurement precision analysis based on the principles of nanometer time-grating sensors.Second harmonics errors are deduced in theory and tranced back in terms of unequal amplitude and phase deviation for two channels of standing waves when the moving ruler is not parallel to yz-plane or deviate from yz-plane.Experiment results show that the original errors for one pitch decrease from 4.86 μm to 0.84 μm by adjusting the assembly parameters of the moving ruler in the yz-plane and xy-plane,which demonstrates that second harmonics error is caused by un-parallel to yz-plane or deviation from yz-plane for moving ruler.The peak-to-peak value of the measurement error is 400 nm within 200 mm measurement range.The proposed theoretical analysis is valid by the experimental results,and provide strong supporting for optimizing the sensor's structure parameters and improving experimental methods,which is very valuable for improving the measurement precision of nanometer time-grating sensor as reliable theory.%为了解析安装参数与测量精度的关系,根据纳米时栅的基本测量原理,构建出与动、定尺间距d0和正对面积变化量ΔS相关的数学模型.通过理论推导,分析了动尺在yz平面倾斜、xy平面偏转时会导致两路驻波幅值不等、相位偏移,从而给测量结果带来二次误差.实验结果表明通过调整动尺在yz平面与xy平面上的安装,对极内原始误差由4.86μm降低至0.84μm,证明动尺在yz平面倾斜、xy平面偏转为产生二次误差的主要原因.在行程200mm测量范围内,传感器误差峰峰值为400nm.实验结果验证了理论分析的正确性,该分析为传感器结构参数优化和实验方法的改进提供了有力的支撑,为进一步提升传感器精度提供了可靠的理论依据.