基于数字解调与涡流技术的涂层厚度测量方法  

Coating thickness measurement method based on digital demodulation and eddy current technology

作　　者：王选择[1,2] 方诗雪 程斌 刘武平 翟中生[1,2] WANG Xuanze;FANG Shixue;CHENG Bin;LIU Wuping;ZHAI Zhongsheng(College of Mechanical Engineering,Hubei University of Technology,Wuhan 430068,China;Hubei Key Laboratory of Modern Manufacture Quality Engineering,Wuhan 430068,China)

机构地区：[1]湖北工业大学机械工程学院,湖北武汉430068 [2]湖北省现代制造质量工程重点实验室,湖北武汉430068

出　　处：《传感器与微系统》2021年第10期114-117,共4页Transducer and Microsystem Technologies

基　　金：国家自然科学基金资助项目(51575164);湖北省教育厅重点项目(D20161406)。

摘　　要：针对金属基体的非金属材质涂层的厚度测量,提出一种基于数字解调与涡流技术的检测方法。针对拾取涡流信号的电感式传感探头,理论分析了涡流电感大小与涂层厚度之间的关系。设计了集激励与放大处理为一体的对称式低噪差分电路,并采用STM32单片机对差分放大信号进行采集与处理。应用基于数字解调原理的信号拟合算法,自动求解采集信号的特征值。以提离距离测量代替涂层厚度测量的方式,搭建了实验平台。使用位移平台按一定步长运动10~500μm的提离量,并利用光栅对平台运动位移进行实时计量。根据测量信号反演算提离量大小。实验结果表明:所提出的检测方法在测量范围内达到相对精度±2%,且有较高的重复性。Aiming at the thickness measurement of non-metallic coatings on metal substrates,a detection method based on digital demodulation and eddy current technology is proposed.For the inductive sensor probe that picks up the eddy current signal,the relationship between the size of the eddy current inductance and the thickness of the coating is theoretically analyzed.A symmetrical low-noise differential circuit integrating excitation and amplifying processing is designed,and STM32 micro-programmed control unit(MCU)is used to collect and process the differential amplified signal.The signal fitting algorithm based on the principle of digital demodulation is applied to automatically solve the characteristic value of the collected signal.An experimental platform is built by using lift-off distance measurement instead of coating thickness measurement.The displacement platform is used to move the lift-off amount of 10~500μm in a certain step length,and the moving displacement of the platform is measured in real time by the grating.The lift-off amount is calculated inversely according to the measurement signal.The experimental results show that the proposed detection method achieves a relative precision of±2%within the measurement range,and has high repeatability.

关 键 词：涡流技术 数字解调 低噪电路 信号拟合 涂层厚度测量 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]