电阻层析成像实时测量系统设计
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摘要
随着工业技术的不断发展,两相/多相流检测需求不断增加,高精度实时的多相流参数检测一直是工程和科研领域尚未有效解决的问题。借助电阻层析成像(ERT)技术可以完成以导电介质为连续相的多相流内部参数可视化测量。目前,ERT技术中检测精度和实时性之间的矛盾,是影响该技术工业化应用的主要原因。本文从ERT技术基本原理出发,研究高精度实时ERT测量系统,以满足实际工业应用需求。
首先,本文在总结目前电阻层析成像国内外研究现状的基础上,介绍了本课题的研究背景、意义、基本思想和论文的章节安排。
其次,在分析电阻层析成像原理、影响系统测量精度和实时性的各方面因素基础上,从硬件和软件设计两个方面详细介绍了电阻成像实时测量系统的基本思路与实现途径。系统采用单电极双极性脉冲电流激励模式设计16电极的电阻层析成像系统,提出采用微控器直接控制高速高精度DAC芯片产生系统激励信号的设计方法,该方法可节省传统的数据同步采集检测模块,简化系统设计。此外,采用程控放大电路和高精度数据采集电路完成系统数据调理与采集,采用串口模式进行实时数据传输。基于Labwindows/CVI开发环境设计了包含串口通信、有限元生成、数据实时成像和测量等功能的上位机处理平台。
最后,给出了系统性能测试结果和进一步改进的方向。从传感器形状、数据采集重复精度和实时成像效果等方面测试了系统实时性与精度。测试结果表明,采用DAC芯片产生激励信号的方法有利于简化系统设计;设计的电阻层析成像系统在满足信号激励、数据采集和软件成像的实时性基础上,测量和成像精度均达到了课题要求。
With the continuous development of industrial technology, the demand for measuring the two-phase/multiphase flow is increasing, but high precision and real-time parameter measurement of multiphase flow has not been resolved effectively in engineering and scientific fields yet. By using the electrical resistance tomography (ERT) technology we can measure the internal parameters of the multiphase flow which has conductive medium as the continuous phase. At present, the main reason for affecting the industrial application of the ERT system is the contradiction of the real-time and nicety in detecting. To meet the needs of the actual industrial applications, we analyze real-time and high precision ERT measurement based on the basic principle of the ERT system.
Firstly, we introduce the research background, research meaning, basic idea of this subject based on the contents and main results of the ERT research.
Secondly, on the basis of analysising on ERT imaging principle, the various factors which influencing the accuracy and real-time, we introduce in detail the basic thoughts and the realize way of the real-time ERT measurement system from both hardware and software design. We use the excitation model of single electrode bi-directional pulse current to design the 16 electrodes ERT system. Under the control of microcontroller, using the DAC chip to generate the excitation source, the design can be simplified and the control module for synchronous data sampling can be not needed. Furthermore we use programmable amplifying circuit and high-precision data acquisition circuit to complete the signal processing and data acquisition, and use the serial mode to transmit the data in real-time. Based on the development environment of the Labwindows/CVI, we design the software processing platform which contains the function of serial communication, FEM mesh generation, the real-time data imaging and measurement.
Finally, the performance test results and the further development trends are be offered. Based on the experiment of the sensor shape, the repeat precision of the data acquisition and the effect of real-time imaging, we test the real time and accuracy of the system. The test result indicates that by using the DAC chip to generate excitation signal, the ERT system can be simplied. On the basis of satisfying the real-time of signal excitation, data acquisition and software imaging, the designed system can reach the requirement of the subject in precision of imaging and measurement.
首先,本文在总结目前电阻层析成像国内外研究现状的基础上,介绍了本课题的研究背景、意义、基本思想和论文的章节安排。
其次,在分析电阻层析成像原理、影响系统测量精度和实时性的各方面因素基础上,从硬件和软件设计两个方面详细介绍了电阻成像实时测量系统的基本思路与实现途径。系统采用单电极双极性脉冲电流激励模式设计16电极的电阻层析成像系统,提出采用微控器直接控制高速高精度DAC芯片产生系统激励信号的设计方法,该方法可节省传统的数据同步采集检测模块,简化系统设计。此外,采用程控放大电路和高精度数据采集电路完成系统数据调理与采集,采用串口模式进行实时数据传输。基于Labwindows/CVI开发环境设计了包含串口通信、有限元生成、数据实时成像和测量等功能的上位机处理平台。
最后,给出了系统性能测试结果和进一步改进的方向。从传感器形状、数据采集重复精度和实时成像效果等方面测试了系统实时性与精度。测试结果表明,采用DAC芯片产生激励信号的方法有利于简化系统设计;设计的电阻层析成像系统在满足信号激励、数据采集和软件成像的实时性基础上,测量和成像精度均达到了课题要求。
With the continuous development of industrial technology, the demand for measuring the two-phase/multiphase flow is increasing, but high precision and real-time parameter measurement of multiphase flow has not been resolved effectively in engineering and scientific fields yet. By using the electrical resistance tomography (ERT) technology we can measure the internal parameters of the multiphase flow which has conductive medium as the continuous phase. At present, the main reason for affecting the industrial application of the ERT system is the contradiction of the real-time and nicety in detecting. To meet the needs of the actual industrial applications, we analyze real-time and high precision ERT measurement based on the basic principle of the ERT system.
Firstly, we introduce the research background, research meaning, basic idea of this subject based on the contents and main results of the ERT research.
Secondly, on the basis of analysising on ERT imaging principle, the various factors which influencing the accuracy and real-time, we introduce in detail the basic thoughts and the realize way of the real-time ERT measurement system from both hardware and software design. We use the excitation model of single electrode bi-directional pulse current to design the 16 electrodes ERT system. Under the control of microcontroller, using the DAC chip to generate the excitation source, the design can be simplified and the control module for synchronous data sampling can be not needed. Furthermore we use programmable amplifying circuit and high-precision data acquisition circuit to complete the signal processing and data acquisition, and use the serial mode to transmit the data in real-time. Based on the development environment of the Labwindows/CVI, we design the software processing platform which contains the function of serial communication, FEM mesh generation, the real-time data imaging and measurement.
Finally, the performance test results and the further development trends are be offered. Based on the experiment of the sensor shape, the repeat precision of the data acquisition and the effect of real-time imaging, we test the real time and accuracy of the system. The test result indicates that by using the DAC chip to generate excitation signal, the ERT system can be simplied. On the basis of satisfying the real-time of signal excitation, data acquisition and software imaging, the designed system can reach the requirement of the subject in precision of imaging and measurement.
引文
[1] Hetsroni G, Handbook of Multiphase System, Hemisphere Publishing Corporation, 1982.
[2] Dickin F, Wang M., Electrical Resistance Tomography for Process Application, Measurement Science &Technology, 1996, 7(3), 247-260.
[3]王晓东,董守平.石油多相流计量研究的现状和发展趋势[J].油气田地面工程(OGSE),1999,Vo1.18(2):4-7.
[4]魏颖.电阻层析成象技术(ERT)及其在两相流测量中的应用研究[D].沈阳:东北大学博士学位论文, 2001.
[5]潘卫国,李杨等.过程层析成像技术的现状与展望[J].仪器仪表学报,2004, 25(4):1034-1036.
[6]董峰,邓湘等.过程层析成像技术综述[J].仪器仪表用户, 2001, Vol.8(1): 6-11.
[7] Campus Geophysical Instruments Ltd., Campus Resistity Products Vincent Drive, Edgbaston, Birmingham B15 2SQ.
[8] Metherall P., Barber D.C., Smallwood R.H & Brown B.H., Three-dimensional Electrical Impedance Tomography, Letters to Nature, Vol.380,No.11, 1996, 509-512.
[9] Mohd Z. Abdullah, Electrical Impedance Tomography for Imaging Conducting Mixtures in Hydrocyclone Separators, Ph.D thesis of University of Manchester, 1993.
[10] R. Mann, F. J. Dickin, M. Wand et al., Application of electrical resistance tomography to interrogate mixing process at plant scale, Chemical Engineering Science, Vo1.52, No.13, 1997, pp.2087-2097.
[11] J. J. Cillierts, W. Xie, S. J. Neethling et al., Electrical Resistance Tomography Using a Bi-directional Current Pulse Technique, Measurement Science and Technology, vo1.12, No.B, 2001, pp.997-1001.
[12] J. Wilkinson, E. W. Randall, D. Durrett, et al.,The Design of a 1000 Frames/Second ERT Data Capture System and Calibration Techniques Employed, 3rd World Congress on Industrial Process Tomography, Banff, Canada, 2003, pp.504-509.
[13] Y Ma, N. Holiday and M. Wand, A High Performance Online Data Processing EIT System, 3rd World Congress on Industrial Process Tomography, Banff, Canada, 2003, pp.27-33.
[14]黄海波.基于双极性脉冲电流激励的ERT系统的研制及其在两相流测量中的应用研究[D].浙江大学硕士学位论文.2004:24-25.
[15] M.Wang, W.Yin. A high adaptive Electrical Impedance Sensing System for Flow Measurement. Measurement Science and Technology, 2002, 13(12):1884-1889.
[16] X.Deng, F.Dong, L.J.Xu, et a1. The Design of a dual-plane ERT System for Cross Correlation Measurement of Bubbly Gas/Liquid Pipe Flow. Measurement Science and Technology, 2001, 12(8):1024-1031.
[17]刘军文.基于单电极激励模式的电阻层析成像技术的研究[D].天津大学硕士论文. 2005.
[18]李忠元.电磁场边界元素法[M].北京:北京工业出版社,1987.
[19]李海青,黄志尧.特种检测技术及应用[M].杭州:浙江大学出版社,2000.
[20]胡松钰.电阻层析成像系统设计[D].浙江大学硕士论文,2008.
[21]魏颖.电阻层析成象技术(ERT)及其在两相流测量中的应用研究.东北大学博士学位论文. 2001.
[22]马艺馨.电阻层析成象技术及其在气/液两相泡状流检测中的应用[D].天津大学博士学位论文, 1999.
[23] Hua Ping et al, Using compound electrodes in electrical impedance tomography[J], IEEE Trans. On BilEng. Vol.40, 1993, pp39-34.
[24] Sansen W., Geeraerts B., Petegem W. Van, et al.. Electrical impedance tomography systems based on voltage drive. Clinical Physics and Physiological Measurement, 1992, 13, Supplement A:39-42.
[25] Barber D.C., Brown B.H.. Applied potential tomography. Journal of Physics E: Scientific Instruments, 1984,17:423-733.
[26] Kotre C.J.. A sensitivity coefficient method for the reconstruction of electrical impedance tomograms. Clinical Physics and Physiological Measurement, 1989, 10(3):275-281.
[27]马艺馨,郑之初等. ERT系统相邻与相对激励模式的研究[J].东北大学学报,2000,21, Sl:173-176.
[28]易红英.电阻抗断层成像[J].山东生物医学工程,2001,20(1):32-36.
[29]马艺馨,徐苓安,姜常珍等.电阻层析成像技术研究[J].仪器仪表学报,2001,22(2):195-213.
[30] Ping Hua et al. Effect of the measurement method on noise handing and image quality for EIT imaging. IEEE Ninth Annual Conference of the Engineering in Medicine and Biology Society, 1987:1429-1430.
[31]姜常珍,孙永进,徐苓安.电阻层析成像(ERT)中的一种新的物理模型[J].仪器仪表学报,2003,(24)5:517-520.
[32] Wang M, Fraser Dickin J et al. Electrical Resistance Tomography on Metal Wall Vessels. ECAPT’94:163-169.
[33] Barber D C, Brown B H, Applied potential tomography, Journal Physics E: Science Instrument 1984, 17(9): 723-733.
[34] Sastry, C.S., Das, P.C., A convolution back projection algorithm for local tomography, Australian & New Zealand Industrial and Applied Mathematics Journal,2005,46: 341-360
[35] Robert Guardo, Christian Boulary, Bruno Murray, et al., An Experimental Study in Electrical Impedance Tomography Using Backprojection Reconstruction, IEEE Transactions on Biomedical Engineering, 1991, 38(7):617-627.
[36]付峰,土志敏,董秀珍等.电阻抗断层成像中Newton-Raphson重构算法的计算机模拟研究[J].第四军医大学学报,1996, 17(1):55-58.
[37]杜岩,柳重堪,程吉宽.电阻抗成像的加权Newton-Raphson算法[J].北京航空航天大学学报,1998, 24(12):161-164.
[38]王化祥,王超,陈磊.基于Landweber迭代的图像重建算法[J].信号处理,2000,16(4): 354-356.
[39]王化祥,朱学明,张立峰.用于电容层析成像技术的共扼梯度算法[J].天津大学学报,2005,38(1):1-4.
[40] Ji Hoon Kim, Bong Yeol Chol, Kyung Youn Kim. Novel iterative image reconstruction algorithm for electrical capacitance tomography: directional algebraic reconstruction technique, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 2006, E89-A(6):1578-1584.
[41] Datta A. N., Bandyopadhyay B.. An improved SIRT-style reconstruction algorithm formicrowave tomography, IEEE Transactions on Biomedical Engineering, 1985,BME-32 (9):719-723.
[42] Zhao Jinchuang, Lu Jianbo, Fu Wenli, et al.. Research on 3-D image reconstruction of electrical capacitance tomography and its application to discrete phase volume measurement of two-phase flow, Chinese Journal of Scientific Instrument, 2005, 26(2):202-205.
[43]王化祥,汪婧,胡理等. ERT/ECT双模态敏感阵列电极优化设计[J].天津学报,2008, 41(8): 911-918.
[44]王建新等. LabWindows/CVI测试技术及工程应用[M].北京:化学工业出版社,2006.
[45]蒋孝煜.有限元法基础.北京:清华大学出版社,1992.
[46]倪光正,钱秀英.电磁场数值计算.北京:高等教育出版社,1996.
[47]王勖成,邵敏.有限单元法基本原理和数值方法.北京:清华大学出版社,1997.
[48]曾余庚,徐国华.电磁场有限单元法.北京:科学出版社,1984.
[49]余金华.电阻层析成像技术应用研究[D].浙江大学博士学位论文,2005.
[50] L K Huang, M J Wang. Image thresholding by minimizing the measures of fuzziness[J]. Pattern Recognition,1995,21(1):41-45.
[51] Wang M, Ma Y X, Holliday N, Dai Y F, et al.. A High-Performance EIT System. IEEE Sensor Journal,2005,5(2):289-299.
[2] Dickin F, Wang M., Electrical Resistance Tomography for Process Application, Measurement Science &Technology, 1996, 7(3), 247-260.
[3]王晓东,董守平.石油多相流计量研究的现状和发展趋势[J].油气田地面工程(OGSE),1999,Vo1.18(2):4-7.
[4]魏颖.电阻层析成象技术(ERT)及其在两相流测量中的应用研究[D].沈阳:东北大学博士学位论文, 2001.
[5]潘卫国,李杨等.过程层析成像技术的现状与展望[J].仪器仪表学报,2004, 25(4):1034-1036.
[6]董峰,邓湘等.过程层析成像技术综述[J].仪器仪表用户, 2001, Vol.8(1): 6-11.
[7] Campus Geophysical Instruments Ltd., Campus Resistity Products Vincent Drive, Edgbaston, Birmingham B15 2SQ.
[8] Metherall P., Barber D.C., Smallwood R.H & Brown B.H., Three-dimensional Electrical Impedance Tomography, Letters to Nature, Vol.380,No.11, 1996, 509-512.
[9] Mohd Z. Abdullah, Electrical Impedance Tomography for Imaging Conducting Mixtures in Hydrocyclone Separators, Ph.D thesis of University of Manchester, 1993.
[10] R. Mann, F. J. Dickin, M. Wand et al., Application of electrical resistance tomography to interrogate mixing process at plant scale, Chemical Engineering Science, Vo1.52, No.13, 1997, pp.2087-2097.
[11] J. J. Cillierts, W. Xie, S. J. Neethling et al., Electrical Resistance Tomography Using a Bi-directional Current Pulse Technique, Measurement Science and Technology, vo1.12, No.B, 2001, pp.997-1001.
[12] J. Wilkinson, E. W. Randall, D. Durrett, et al.,The Design of a 1000 Frames/Second ERT Data Capture System and Calibration Techniques Employed, 3rd World Congress on Industrial Process Tomography, Banff, Canada, 2003, pp.504-509.
[13] Y Ma, N. Holiday and M. Wand, A High Performance Online Data Processing EIT System, 3rd World Congress on Industrial Process Tomography, Banff, Canada, 2003, pp.27-33.
[14]黄海波.基于双极性脉冲电流激励的ERT系统的研制及其在两相流测量中的应用研究[D].浙江大学硕士学位论文.2004:24-25.
[15] M.Wang, W.Yin. A high adaptive Electrical Impedance Sensing System for Flow Measurement. Measurement Science and Technology, 2002, 13(12):1884-1889.
[16] X.Deng, F.Dong, L.J.Xu, et a1. The Design of a dual-plane ERT System for Cross Correlation Measurement of Bubbly Gas/Liquid Pipe Flow. Measurement Science and Technology, 2001, 12(8):1024-1031.
[17]刘军文.基于单电极激励模式的电阻层析成像技术的研究[D].天津大学硕士论文. 2005.
[18]李忠元.电磁场边界元素法[M].北京:北京工业出版社,1987.
[19]李海青,黄志尧.特种检测技术及应用[M].杭州:浙江大学出版社,2000.
[20]胡松钰.电阻层析成像系统设计[D].浙江大学硕士论文,2008.
[21]魏颖.电阻层析成象技术(ERT)及其在两相流测量中的应用研究.东北大学博士学位论文. 2001.
[22]马艺馨.电阻层析成象技术及其在气/液两相泡状流检测中的应用[D].天津大学博士学位论文, 1999.
[23] Hua Ping et al, Using compound electrodes in electrical impedance tomography[J], IEEE Trans. On BilEng. Vol.40, 1993, pp39-34.
[24] Sansen W., Geeraerts B., Petegem W. Van, et al.. Electrical impedance tomography systems based on voltage drive. Clinical Physics and Physiological Measurement, 1992, 13, Supplement A:39-42.
[25] Barber D.C., Brown B.H.. Applied potential tomography. Journal of Physics E: Scientific Instruments, 1984,17:423-733.
[26] Kotre C.J.. A sensitivity coefficient method for the reconstruction of electrical impedance tomograms. Clinical Physics and Physiological Measurement, 1989, 10(3):275-281.
[27]马艺馨,郑之初等. ERT系统相邻与相对激励模式的研究[J].东北大学学报,2000,21, Sl:173-176.
[28]易红英.电阻抗断层成像[J].山东生物医学工程,2001,20(1):32-36.
[29]马艺馨,徐苓安,姜常珍等.电阻层析成像技术研究[J].仪器仪表学报,2001,22(2):195-213.
[30] Ping Hua et al. Effect of the measurement method on noise handing and image quality for EIT imaging. IEEE Ninth Annual Conference of the Engineering in Medicine and Biology Society, 1987:1429-1430.
[31]姜常珍,孙永进,徐苓安.电阻层析成像(ERT)中的一种新的物理模型[J].仪器仪表学报,2003,(24)5:517-520.
[32] Wang M, Fraser Dickin J et al. Electrical Resistance Tomography on Metal Wall Vessels. ECAPT’94:163-169.
[33] Barber D C, Brown B H, Applied potential tomography, Journal Physics E: Science Instrument 1984, 17(9): 723-733.
[34] Sastry, C.S., Das, P.C., A convolution back projection algorithm for local tomography, Australian & New Zealand Industrial and Applied Mathematics Journal,2005,46: 341-360
[35] Robert Guardo, Christian Boulary, Bruno Murray, et al., An Experimental Study in Electrical Impedance Tomography Using Backprojection Reconstruction, IEEE Transactions on Biomedical Engineering, 1991, 38(7):617-627.
[36]付峰,土志敏,董秀珍等.电阻抗断层成像中Newton-Raphson重构算法的计算机模拟研究[J].第四军医大学学报,1996, 17(1):55-58.
[37]杜岩,柳重堪,程吉宽.电阻抗成像的加权Newton-Raphson算法[J].北京航空航天大学学报,1998, 24(12):161-164.
[38]王化祥,王超,陈磊.基于Landweber迭代的图像重建算法[J].信号处理,2000,16(4): 354-356.
[39]王化祥,朱学明,张立峰.用于电容层析成像技术的共扼梯度算法[J].天津大学学报,2005,38(1):1-4.
[40] Ji Hoon Kim, Bong Yeol Chol, Kyung Youn Kim. Novel iterative image reconstruction algorithm for electrical capacitance tomography: directional algebraic reconstruction technique, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 2006, E89-A(6):1578-1584.
[41] Datta A. N., Bandyopadhyay B.. An improved SIRT-style reconstruction algorithm formicrowave tomography, IEEE Transactions on Biomedical Engineering, 1985,BME-32 (9):719-723.
[42] Zhao Jinchuang, Lu Jianbo, Fu Wenli, et al.. Research on 3-D image reconstruction of electrical capacitance tomography and its application to discrete phase volume measurement of two-phase flow, Chinese Journal of Scientific Instrument, 2005, 26(2):202-205.
[43]王化祥,汪婧,胡理等. ERT/ECT双模态敏感阵列电极优化设计[J].天津学报,2008, 41(8): 911-918.
[44]王建新等. LabWindows/CVI测试技术及工程应用[M].北京:化学工业出版社,2006.
[45]蒋孝煜.有限元法基础.北京:清华大学出版社,1992.
[46]倪光正,钱秀英.电磁场数值计算.北京:高等教育出版社,1996.
[47]王勖成,邵敏.有限单元法基本原理和数值方法.北京:清华大学出版社,1997.
[48]曾余庚,徐国华.电磁场有限单元法.北京:科学出版社,1984.
[49]余金华.电阻层析成像技术应用研究[D].浙江大学博士学位论文,2005.
[50] L K Huang, M J Wang. Image thresholding by minimizing the measures of fuzziness[J]. Pattern Recognition,1995,21(1):41-45.
[51] Wang M, Ma Y X, Holliday N, Dai Y F, et al.. A High-Performance EIT System. IEEE Sensor Journal,2005,5(2):289-299.