基于LMS自适应时延估计的高精度超声测厚系统  

High⁃precision ultrasonic thickness measurement system based on LMS adaptive time delay estimation algorithm

作　　者：杨定强 刘继兵 王念 李瑞君[1] YANG Dingqiang;LIU Jibing;WANG Nian;LI Ruijun(Anhui Province Key Laboratory of Measuring Theory and Precision Instrument,School of Instrument Science and Opto-electronics Engineering,Hefei University of Technology,Hefei 230009,China;Bengbu Special Equipment Supervision and Inspection Center,Bengbu 233090,China)

机构地区：[1]合肥工业大学仪器科学与光电工程学院测量理论与精密仪器安徽省重点实验室,安徽合肥230009 [2]蚌埠市特种设备监督检验中心,安徽蚌埠233090

出　　处：《计测技术》2024年第4期79-87,共9页Metrology & Measurement Technology

基　　金：国家自然科学基金项目(52175506);安徽省市场监督管理局科技计划项目(2022MK051)。

摘　　要：针对现有超声测厚系统精度较低的问题,研制基于最小均方(Least Mean Square,LMS)自适应时间延迟估计的高精度超声测厚系统。设计超声发射及接收电路,研发基于现场可编程门阵列(Field Programmable Gate Array,FPGA)的高速数据采集及传输系统,开发基于MATLAB的上位机信号处理软件,通过LMS自适应时间延迟估计算法准确、高效地计算超声飞行时间(Time of Flight,TOF),从而实现高精度厚度测量。开展模拟回波仿真实验,结果显示:相较峰值法、包络法和相关法,LMS法在时间延迟估计方面更具优势。搭建基于LMS自适应时延估计的超声测厚系统,以量块为对象进行测厚实验,结果表明:该系统测厚相对误差小于3.77%,重复实验标准差不高于0.2μm,最大相对不确定度为1.4%。基于LMS自适应时延估计的超声测厚系统可应用于板材厚度测量等领域,有利于推动高精度超声测厚技术发展,具有重要技术借鉴价值。A high⁃precision ultrasonic thickness measurement system based on the least mean square(LMS)adaptive time delay estimation algorithm was developed,addressing the issue of low accuracy of the existing ultrasonic thickness measurement systems.The ultrasonic transmitting and receiving circuits were designed.The high⁃speed data acquisition and transmission system based on field programmable gate array(FPGA)was developed.The host computer signal processing software based on MATLAB was developed.The ultrasonic time of flight(TOF)was calculated accurately and efficiently by LMS adaptive time delay estimation algorithm,so as to realize high⁃precision thickness measurement.The simulated echo simulation experiments were conducted.The results show that the LMS method has more advantages in time delay estimation than the peak method,envelope method and correlation method.An ultrasonic thickness measurement system based on LMS adaptive time delay estimation algorithm was built,and the thickness measurement experiments were performed on gauge blocks.The results show that the relative error of thickness measurement is less than 3.77%,the standard deviation of repeated experiment is not higher than 0.2μm,and the maximum relative measurement uncertainty is 1.4%.The ultrasonic thickness measurement system based on LMS adaptive time delay estimation algorithm can be applied in the fields such as plate thickness measurement,which is conducive to promoting the development of high⁃precision ultrasonic thickness measurement technology and has important technical reference value.

关 键 词：超声 测厚 飞行时间 最小均方自适应时延估计 

分 类 号：TB92[一般工业技术—计量学] TB551[机械工程—测试计量技术及仪器] O426.9[理学—物理]