基于FPGA的电磁超声检测系统的研究
摘要
由于电磁超声技术检测效率高、环境适应性强,因此被广泛应用于无损在线检测研究领域。FPGA灵活性强、处理速度高,在实时信号处理中具有独特优势。本文研究基于FPGA的电磁超声检测系统具有重要的理论意义和实用价值。
本文在深入研究国内外电磁超声检测方法的基础上,分析了电磁超声换能器(electromagnetic acoustic transducers,EMAT)的工作机理,成功研制了基于FPGA的电磁超声检测系统。该系统包括电磁超声发射、接收电路、基于FPGA的数字信号处理和基于SOPC的缺陷检测部分。
基于DDS技术的电磁超声发射电路能够产生高频、大功率正弦电流脉冲串,脉冲串的频率、重复频率、波数及幅度均连续可调。本文设计的电磁超声接收电路具备强噪声背景下的微弱信号检测能力,采用2级级联的二阶无限增益多路反馈带通滤波电路能够显著提高接收信号的信噪比。
本文在分析电磁超声接收信号成分及噪声来源的基础上,采用FIR带通滤波与小波消噪算法有效地降低了电磁超声接收信号中的噪声含量,并利用数字检波方法提取了接收信号的包络。上述算法通过硬件描述语言编程,并由FPGA实现,提高了检测系统的灵活性与实时性。
本文基于SOPC技术实现了对消噪后接收信号的采集、缺陷判断、缺陷定位与显示。采用所研制的基于FPGA的电磁超声检测系统进行了钢板缺陷检测、声场指向性测量和列车轮对检测实验。实验结果验证了检测方法的有效性与正确性。该系统的研制为电磁超声在线检测技术的工程应用奠定了良好的基础。
Electromagnetic ultrasonic technology is widely used in on-line, high-speed and high-temperature nondestructive detection fields due to its high detection efficiency and adaptability of environment, while FPGA possesses unique advantages in real-time signal processing field resulted from its characteristics of flexibility and high processing speed. As a consequence, the research of an electromagnetic ultrasonic detection system based on FPGA is of great theoretical and practical value.
Based on extensive study of the present researching status of electromagnetic ultrasonic technology, this paper analyzes the mechanism of the electromagnetic acoustic transducers (EMATs), and successfully develops an electromagnetic ultrasonic detection system based on FPGA. The system consists of electromagnetic ultrasonic transmitting and receiving circuits, digital signal processing module based on FPGA and defects detection module based on SOPC.
Based on DDS technology, the transmitting circuit designed in this paper is able to generate tone burst signal with high frequency and large power, whose repetitive frequency, frequency, number of waves and magnitude can be continuously adjusted. The receiving circuit designed in this paper has a strong ability of weak signal detection under a strong noise environment. A second-order infinite-gain multi-feedback band-pass filter designed in this paper has a good performance in improving the signal-to-noise ratio of the EMAT received signal.
Based on analyzing the components of the received signals and noise sources, this paper adopts FIR band-pass filtering and wavelet denoising algorithm to effectively denoise the received signal. Digital demodulation method is used to extract the envelope of the received signals. The flexibility and real-time quality of the detection system is greatly enhanced utilizing hardware description language realized by FPGA.
Functions of data acquisition, defect detection, defect localization and display are realized based on SOPC technology. Experiments of steel plate defect detection, sound field directivity measurement and train wheel detection implemented by the designed system have verified the validity of the system. The design of this system establishes a solid foundation for practical application of the electromagnetic ultrasonic online detection.
本文在深入研究国内外电磁超声检测方法的基础上,分析了电磁超声换能器(electromagnetic acoustic transducers,EMAT)的工作机理,成功研制了基于FPGA的电磁超声检测系统。该系统包括电磁超声发射、接收电路、基于FPGA的数字信号处理和基于SOPC的缺陷检测部分。
基于DDS技术的电磁超声发射电路能够产生高频、大功率正弦电流脉冲串,脉冲串的频率、重复频率、波数及幅度均连续可调。本文设计的电磁超声接收电路具备强噪声背景下的微弱信号检测能力,采用2级级联的二阶无限增益多路反馈带通滤波电路能够显著提高接收信号的信噪比。
本文在分析电磁超声接收信号成分及噪声来源的基础上,采用FIR带通滤波与小波消噪算法有效地降低了电磁超声接收信号中的噪声含量,并利用数字检波方法提取了接收信号的包络。上述算法通过硬件描述语言编程,并由FPGA实现,提高了检测系统的灵活性与实时性。
本文基于SOPC技术实现了对消噪后接收信号的采集、缺陷判断、缺陷定位与显示。采用所研制的基于FPGA的电磁超声检测系统进行了钢板缺陷检测、声场指向性测量和列车轮对检测实验。实验结果验证了检测方法的有效性与正确性。该系统的研制为电磁超声在线检测技术的工程应用奠定了良好的基础。
Electromagnetic ultrasonic technology is widely used in on-line, high-speed and high-temperature nondestructive detection fields due to its high detection efficiency and adaptability of environment, while FPGA possesses unique advantages in real-time signal processing field resulted from its characteristics of flexibility and high processing speed. As a consequence, the research of an electromagnetic ultrasonic detection system based on FPGA is of great theoretical and practical value.
Based on extensive study of the present researching status of electromagnetic ultrasonic technology, this paper analyzes the mechanism of the electromagnetic acoustic transducers (EMATs), and successfully develops an electromagnetic ultrasonic detection system based on FPGA. The system consists of electromagnetic ultrasonic transmitting and receiving circuits, digital signal processing module based on FPGA and defects detection module based on SOPC.
Based on DDS technology, the transmitting circuit designed in this paper is able to generate tone burst signal with high frequency and large power, whose repetitive frequency, frequency, number of waves and magnitude can be continuously adjusted. The receiving circuit designed in this paper has a strong ability of weak signal detection under a strong noise environment. A second-order infinite-gain multi-feedback band-pass filter designed in this paper has a good performance in improving the signal-to-noise ratio of the EMAT received signal.
Based on analyzing the components of the received signals and noise sources, this paper adopts FIR band-pass filtering and wavelet denoising algorithm to effectively denoise the received signal. Digital demodulation method is used to extract the envelope of the received signals. The flexibility and real-time quality of the detection system is greatly enhanced utilizing hardware description language realized by FPGA.
Functions of data acquisition, defect detection, defect localization and display are realized based on SOPC technology. Experiments of steel plate defect detection, sound field directivity measurement and train wheel detection implemented by the designed system have verified the validity of the system. The design of this system establishes a solid foundation for practical application of the electromagnetic ultrasonic online detection.
引文
1赵再新.基于电磁超声的火车车轮检测系统的初步研究.哈尔滨工业大学.工学硕士论文. 2005:1~55
2康磊.用于火车车轮在线检测的电磁超声换能器的研究.哈尔滨工业大学.工学硕士论文. 2006
3雷华明.电磁超声换能机理研究及其在管道检测中的应用探索.上海交通大学.博士论文. 2005
4潘松,王国栋. VHDL实用教程.第一版.成都:电子科技大学出版社,2000,9-10
5许守平译,张广纯校. ASTM E816-96利用电磁超声换能器(EMAT)技术进行超声检查的标准方法.无损探伤.第27卷,第2期. 2003. 4:20~28
6张建卫译,张广纯校. ASTM E1774-96电磁超声换能器(EMAT)标准导则.无损探伤.第27卷,第1期.2003. 2:18~23.
7张伟代译,张广纯校. ASTM E1962-98利用电磁超声换能器(EMAT)技术进行超声表面检查的标准检测方法.无损探伤.第27卷,第3期.2003.6:30~35
8 H. Yamada, Y. Yano, T. Udagawa. Development of the Phased Array System for Angle Beam Testing. NIPPON Steel Technical Report, 2004, (89): 28-32
9张勇,陈强,孙振国,汤晓华.用于无损检测的电磁超声换能器研究进展无损检测. Vol.26(6),june,2004:275~279
10 C. Edwards, S. B. Palmer. Wideband Electromagnetic Acoustic Transducers Utilising Neodymium Iron Boron Permanent Magnets. IEEE Trans. on Magnetics.. 1990, 26(5): 2080~2084
11 K. Sawaragi, H. J. Salzburger, G. Hubschen, et al. Improvement of SH-wave EMAT Phased Array Inspection by New Eight Segment Probes. Nuclear Engineering and Design, 2000: 153-163
12 H. Yamada, Y. Yano, T. Udagawa. Development of the Phased Array System for Angle Beam Testing. NIPPON Steel Technical Report, 2004, (89): 28-32
13 M. Kaltenbacher, R. Lerch, H. Landes, et al. Computer Optimization of Electromagnetic Acoustic Transducers. IEEE Ultrasonics Symposium, 1998: 1029-1034
14 Reinhold Ludwig, William Lord. A finite-element formulation for the study of ultrasonic NDT systems. IEEE Trans. Ultrasonic, Ferroelectrics and Frequency Control. Vol.35,No.6,Nov 1988:809~820
15 Reinhold Ludwig. Theoretical basis for a unified conservation law description of the electromagnetic acoustic transduction process. IEEE Trans. Ultrasonics, Ferroelectrics, and Frequency Control, VoL39, No.4, July 1992:476-480
16 Reinhold Ludwig. Numerical implementation and model predictions of a unified conservation law description of the electromagnetic acoustic transduction process. IEEE Trans. Ultrasonic, Ferroelectrics and Frequency Control. Vo1.39, No.4. July 1992:481~488
17 R. Ludwig, Z. You, R. Palanisamy. Numerical simulation of an Electromagnetic acoustic transducer-receiver system for NDT Application. IEEE Trans. Magnetics, Vol.29, No.3. May 1993:2081-2089
18 Dai Xiao-wei, Electromagnetic Acoustic transducers: Physical principles and finite element modeling, Ph.D Dissertation. Worester Polytechnic Institute. 1991
19 Xiao-wei Dai, Reinhold Ludwig, R. Palanisamy. Numerical simulation of pulsed eddy-current nondestructive testing phenomena. IEEE Trans. Magnetics, Vo1.26, No.6. Nov 1990:3089~3096
20 Hirotsugu Ogi, Masahiko Hirao, Toshihiro Ohtani. Line-focusing of ultrasonic SV wave by electromagnetic acoustic transducer. Journal of the Acoustical Society of America, 1998, Vol.103:2411~2415
21 Hirotsugu Ogi, Masahiko Hirao, Toshihiro Ohtani. Line-focusing electromagnetic acoustic transducers for the detection of slit defects. IEEE Tran Ultrasonics, Febroelectrics, and Frequency Control, 1999, 46(2): 341~368
22 S. Legendre, D. Massicotte, J. Goyette. Wavelet-Transform-Based Method of Analysis for Lamb-Wave Ultrasonic NDE Signals. IEEE Trans. on Instrumentation and Measurement. 2000, 49(3): 524~530
23 S. Legendre, D. Massicotte, J. Goyette. Neural Classification of Lamb Wave Ultrasonic Weld Testing Signals Using Wavelet Coefficient. IEEE Trans. on Instrumentation and Measurement. 2001, 50(3): 672~678.
24 X.J.Wu, W.M.Cuo, W. S. Cai. A method based on stochastic resonance for the detection of weak analytical signal. Talanta. 2003,16: 863-869
25 C.Y.Song, YH.Lei, S.Q.Ding. Application of chaos to weak signal detection.Editorial Board of Journal of Harbin Engineering, Harbin, 2004,25:2123
26许庆译自, Vo1.24, No.4, 1991.用于钢管的电磁超声波壁厚计. (日本)山崎一男.国外计量. 1991年,第5期.
27 S. Dixon, C. Edwards, S. B. Palmer. High accuracy non-contact ultrasonic thickness gauging of aluminium sheet using electromagnetic acoustic transducers. Ultrasonics, Vol.39, 2001:445~453
28曹建海,严拱标,韩晓枫.电磁超声测厚原理及其应用——一种新型超声测厚法.浙江大学学报(工学版).Vol.36, No.l, 2002
29 H. J. Salzburger, G. Dobmann, H. Mohrbacher. Quality control of laser welds of tailored blanks using guided waves and EMATs. IEEE Proc.-Sci. Meas. Technol. Vol.48(4), July 2001:143~148
30 B. Tittmann, R. Alers and R. Lerch. Ultrasonics for Locomotive Wheel Integrity. 2000 IEEE Ultrasonics Symposium. 2000:743~746
31 Z. F. Mian, W. Peabody, T. Haller. Wheel Inspection System. United States Patent. US: 6523411B1, 2003
32张广纯,陆原,李希英等.电磁超声自动探伤技术.中国专利: CN1051086A. 1991
33陈苏劲,张广纯,梁杰宇.电磁声探伤装置.中国专利: CN2090061U. 1991
34张广纯.电磁声技术的进展与应用.无损检测. 1990, 12(4):103~106
35国家十五863计划“海底管道内爬行器及其检测技术”课题实施方案报告.
36刘守山.超声数字信号处理系统可重构架构的研究.浙江大学.博士论文. 2007:5~14
37赵雅兴. FPGA原理、设计与应用.第一版.天津:天津大学出版社,1999:36~38
38张伟代,译. ASTM E1962-98利用电磁声换能器(EMAT)技术进行超声表面检查的标准检测方法.无损探伤. 2003, 27(3):30~35
39 J.西拉德.超声检测新技术.科学出版社, 1991: 362~389
40 Lerch R. Simulations of piezoelectric devices by two and three dimensional finite element. IEEE trans Ultra, Ferroelec, Frequ Contrl.1990,37(3):233-247
41 Jafari Shapoorabadi R, Sinclair AN. Improved finite element method for EMAT analysis and design. IEEE Tran Magnetics.2001,37(4):2821-2823
42中国机械工程学会无损检测分会编.超声波检测.机械工业出版社. 2000:34~36
43刘成尧.基于DDS技术的任意波形发生器设计.电子技术, 2002(10):21~24
44 D.E.约翰逊.有源滤波器的快速实用设计.人民邮电出版社. 1980:138~169
45董绍平,陈世耕,王洋.数字信号处理基础.哈尔滨工业大学出版社,1996:172~223
46胡广书.现代信号处理教程.清华大学出版社,2004:239~402
47胡昌华,李国华,刘涛,周志杰.基于Matlab的系统分析与设计——小波分析.西安电子科技大学出版社,2004
48 Stephane Maller. A Wavelet Tour of Signal Processing. 2005:5～15
49王选择,杨练根,丁敏.基于乘除法思想的电感传感器检波方法.三峡大学学报,2006,6
50周立功. SOPC嵌入式系统基础教程.北京航空航天大学出版社. 2006
2康磊.用于火车车轮在线检测的电磁超声换能器的研究.哈尔滨工业大学.工学硕士论文. 2006
3雷华明.电磁超声换能机理研究及其在管道检测中的应用探索.上海交通大学.博士论文. 2005
4潘松,王国栋. VHDL实用教程.第一版.成都:电子科技大学出版社,2000,9-10
5许守平译,张广纯校. ASTM E816-96利用电磁超声换能器(EMAT)技术进行超声检查的标准方法.无损探伤.第27卷,第2期. 2003. 4:20~28
6张建卫译,张广纯校. ASTM E1774-96电磁超声换能器(EMAT)标准导则.无损探伤.第27卷,第1期.2003. 2:18~23.
7张伟代译,张广纯校. ASTM E1962-98利用电磁超声换能器(EMAT)技术进行超声表面检查的标准检测方法.无损探伤.第27卷,第3期.2003.6:30~35
8 H. Yamada, Y. Yano, T. Udagawa. Development of the Phased Array System for Angle Beam Testing. NIPPON Steel Technical Report, 2004, (89): 28-32
9张勇,陈强,孙振国,汤晓华.用于无损检测的电磁超声换能器研究进展无损检测. Vol.26(6),june,2004:275~279
10 C. Edwards, S. B. Palmer. Wideband Electromagnetic Acoustic Transducers Utilising Neodymium Iron Boron Permanent Magnets. IEEE Trans. on Magnetics.. 1990, 26(5): 2080~2084
11 K. Sawaragi, H. J. Salzburger, G. Hubschen, et al. Improvement of SH-wave EMAT Phased Array Inspection by New Eight Segment Probes. Nuclear Engineering and Design, 2000: 153-163
12 H. Yamada, Y. Yano, T. Udagawa. Development of the Phased Array System for Angle Beam Testing. NIPPON Steel Technical Report, 2004, (89): 28-32
13 M. Kaltenbacher, R. Lerch, H. Landes, et al. Computer Optimization of Electromagnetic Acoustic Transducers. IEEE Ultrasonics Symposium, 1998: 1029-1034
14 Reinhold Ludwig, William Lord. A finite-element formulation for the study of ultrasonic NDT systems. IEEE Trans. Ultrasonic, Ferroelectrics and Frequency Control. Vol.35,No.6,Nov 1988:809~820
15 Reinhold Ludwig. Theoretical basis for a unified conservation law description of the electromagnetic acoustic transduction process. IEEE Trans. Ultrasonics, Ferroelectrics, and Frequency Control, VoL39, No.4, July 1992:476-480
16 Reinhold Ludwig. Numerical implementation and model predictions of a unified conservation law description of the electromagnetic acoustic transduction process. IEEE Trans. Ultrasonic, Ferroelectrics and Frequency Control. Vo1.39, No.4. July 1992:481~488
17 R. Ludwig, Z. You, R. Palanisamy. Numerical simulation of an Electromagnetic acoustic transducer-receiver system for NDT Application. IEEE Trans. Magnetics, Vol.29, No.3. May 1993:2081-2089
18 Dai Xiao-wei, Electromagnetic Acoustic transducers: Physical principles and finite element modeling, Ph.D Dissertation. Worester Polytechnic Institute. 1991
19 Xiao-wei Dai, Reinhold Ludwig, R. Palanisamy. Numerical simulation of pulsed eddy-current nondestructive testing phenomena. IEEE Trans. Magnetics, Vo1.26, No.6. Nov 1990:3089~3096
20 Hirotsugu Ogi, Masahiko Hirao, Toshihiro Ohtani. Line-focusing of ultrasonic SV wave by electromagnetic acoustic transducer. Journal of the Acoustical Society of America, 1998, Vol.103:2411~2415
21 Hirotsugu Ogi, Masahiko Hirao, Toshihiro Ohtani. Line-focusing electromagnetic acoustic transducers for the detection of slit defects. IEEE Tran Ultrasonics, Febroelectrics, and Frequency Control, 1999, 46(2): 341~368
22 S. Legendre, D. Massicotte, J. Goyette. Wavelet-Transform-Based Method of Analysis for Lamb-Wave Ultrasonic NDE Signals. IEEE Trans. on Instrumentation and Measurement. 2000, 49(3): 524~530
23 S. Legendre, D. Massicotte, J. Goyette. Neural Classification of Lamb Wave Ultrasonic Weld Testing Signals Using Wavelet Coefficient. IEEE Trans. on Instrumentation and Measurement. 2001, 50(3): 672~678.
24 X.J.Wu, W.M.Cuo, W. S. Cai. A method based on stochastic resonance for the detection of weak analytical signal. Talanta. 2003,16: 863-869
25 C.Y.Song, YH.Lei, S.Q.Ding. Application of chaos to weak signal detection.Editorial Board of Journal of Harbin Engineering, Harbin, 2004,25:2123
26许庆译自
27 S. Dixon, C. Edwards, S. B. Palmer. High accuracy non-contact ultrasonic thickness gauging of aluminium sheet using electromagnetic acoustic transducers. Ultrasonics, Vol.39, 2001:445~453
28曹建海,严拱标,韩晓枫.电磁超声测厚原理及其应用——一种新型超声测厚法.浙江大学学报(工学版).Vol.36, No.l, 2002
29 H. J. Salzburger, G. Dobmann, H. Mohrbacher. Quality control of laser welds of tailored blanks using guided waves and EMATs. IEEE Proc.-Sci. Meas. Technol. Vol.48(4), July 2001:143~148
30 B. Tittmann, R. Alers and R. Lerch. Ultrasonics for Locomotive Wheel Integrity. 2000 IEEE Ultrasonics Symposium. 2000:743~746
31 Z. F. Mian, W. Peabody, T. Haller. Wheel Inspection System. United States Patent. US: 6523411B1, 2003
32张广纯,陆原,李希英等.电磁超声自动探伤技术.中国专利: CN1051086A. 1991
33陈苏劲,张广纯,梁杰宇.电磁声探伤装置.中国专利: CN2090061U. 1991
34张广纯.电磁声技术的进展与应用.无损检测. 1990, 12(4):103~106
35国家十五863计划“海底管道内爬行器及其检测技术”课题实施方案报告.
36刘守山.超声数字信号处理系统可重构架构的研究.浙江大学.博士论文. 2007:5~14
37赵雅兴. FPGA原理、设计与应用.第一版.天津:天津大学出版社,1999:36~38
38张伟代,译. ASTM E1962-98利用电磁声换能器(EMAT)技术进行超声表面检查的标准检测方法.无损探伤. 2003, 27(3):30~35
39 J.西拉德.超声检测新技术.科学出版社, 1991: 362~389
40 Lerch R. Simulations of piezoelectric devices by two and three dimensional finite element. IEEE trans Ultra, Ferroelec, Frequ Contrl.1990,37(3):233-247
41 Jafari Shapoorabadi R, Sinclair AN. Improved finite element method for EMAT analysis and design. IEEE Tran Magnetics.2001,37(4):2821-2823
42中国机械工程学会无损检测分会编.超声波检测.机械工业出版社. 2000:34~36
43刘成尧.基于DDS技术的任意波形发生器设计.电子技术, 2002(10):21~24
44 D.E.约翰逊.有源滤波器的快速实用设计.人民邮电出版社. 1980:138~169
45董绍平,陈世耕,王洋.数字信号处理基础.哈尔滨工业大学出版社,1996:172~223
46胡广书.现代信号处理教程.清华大学出版社,2004:239~402
47胡昌华,李国华,刘涛,周志杰.基于Matlab的系统分析与设计——小波分析.西安电子科技大学出版社,2004
48 Stephane Maller. A Wavelet Tour of Signal Processing. 2005:5～15
49王选择,杨练根,丁敏.基于乘除法思想的电感传感器检波方法.三峡大学学报,2006,6
50周立功. SOPC嵌入式系统基础教程.北京航空航天大学出版社. 2006