基于变步长LMS算法的交流阻抗测钢筋腐蚀  

Measurement of Rebar Corrosion AC with Impedance Method Based on Variable Step Size LMS Algorithm

作　　者：林旭梅 刘振东 马士强 王雨露 刘云飞 LIN Xu-mei;LIU Zhen-dong;MA Shi-qiang;WANG Yu-lu;LIU Yun-fei(School of Information and Control Engineering,Qingdao University of Technology,Qingdao 266000,China)

机构地区：[1]青岛理工大学信息与控制工程学院

出　　处：《测控技术》2019年第7期93-96,103,共5页Measurement & Control Technology

摘　　要：交流阻抗法在钢筋腐蚀测量中应用比较广泛,为了改善交流阻抗法在测量时由于测量阻抗较大而存在响应信号微弱、信噪比较低、误差较大等问题,提出了一种改进变步长LMS自适应滤波算法。针对传统算法收敛速度慢和稳态误差较大的缺点,改进了步长因子和误差之间的函数关系,使步长因子对时变系统有了一定的跟踪能力。在改进算法的基础上,在不同频率的信号环境中进行仿真和实验,结果表明将改进的算法应用于钢筋腐蚀测量,有效地提高了响应信号的信噪比,同时减小了稳态误差,测量精度可以精确到10 mV左右,为钢筋腐蚀测量提供了一种新的思路和方法。AC impedance method is widely used in the steel corrosion measurement.However,there are many problems in AC impedance measurement,such as weak response signals,low SNR(signal to noise ratio)and large errors.In order to solve these problems,an improved variable step size LMS adaptive filtering algorithmwas proposed.In order to overcome the disadvantages of slow convergence speed and large steady-state error of the traditional algorithms,the function relationship between step factor and error was improved,so that the stepfactor had certain tracking ability to the time-varying system.On the basis of the improved algorithm,simulation and experiments were carried out in different frequency signal environments.The results show that the improved algorithm effectively improves the SNR of the response signal and reduces the steady state error in steel corrosion measurement.The measurement accuracy can reach about 10 mV,which provides a new idea and method for steel corrosion measurement.

关 键 词：交流阻抗法 微弱信号 自适应滤波 变步长LMS算法 信噪比 

分 类 号：TP391.1[自动化与计算机技术—计算机应用技术]