为了精确的测量电涡流传感器的距离 -电压输出线性区间和线性位移精度, 本文采用了显微散斑相关法对位移进行标定。首先, 利用精度为 5 μm位移平台进行位移调节, 得到位移和电涡流传感器输出电压的线性区间。然后, 在线性区间内进行密集采样, 通过显微照相系统采集散斑图, 利用散斑相关法求出位移, 得到更高精度的位移-电压曲线。分析了显微散斑照相的检测流程与检测精度; 讨论了散斑尺寸对测量的影响。设计了测量光路参数: 采用 40×显微物镜配合 20×读数显微镜可以实现 64.5×的放大倍率。对 40铬材料进行了位移 -电压曲线标定实验, 实验结果证明: 本系统可以实现高精度的电涡流传感器位移标定, 测量精度达到 0.09 μm, 要实现更高精度的标定可以提高显微系统的放大倍率。

In order to measure the curves of distance and output voltage for eddy current sensor, a speckle correlation method is proposed. Firstly, the linear interval is measured by the displacement platform with precision of 5um. Secondly, congestion sampling is taken out in the linear interval, the speckle pattern under different distance is captured by the micro-imaging system and more precision curves are obtained with displacement calculated by the speckle correlation method. The precision of measurement is analyzed and the influence of speckle size on measurement is also discussed. The micro-imaging system with magnification of 64.5 is designed by combining an objective with 40 magnifications and a reading microscope with 20 magnifications. The experimental object is the 40 chromium and the results show that the proposed system can achieve high precision calibration for eddy current sensor with 0.09 μm precision and more precision can be obtained by changing the magnification of the imaging system.