基于差压补偿的液体小流量检测方法的研究
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摘要
液体流量是工业生产中的一个重要参数。随着现代工业技术的快速发展,测量环境日益复杂化,人们对流量测量的要求也越来越高,许多流量测量技术问题亟待解决,其中测量精度就是一个重要方面。对于容积式流量计液体小流量的测量,测量误差的主要来源是内部泄漏。
本文首先分析了容积式流量计误差的特性,根据流体力学原理,提出了一种提高容积式流量计液体小流量测量精度的新方法—差压补偿法,阐述了差压补偿法的设计思想,即在流量计的转轴上增加一个起补偿作用的控制电机,控制电机通过定比传动与流量计的转子连接,其转速由流量计入口与出口的压差决定,使流量计转子的转速紧随压差的变化自动调节。结合检测与控制理论,给出了检测系统的总体设计方案。然后,分别对本检测系统的几个组成部分:压差检测、信号采集与转换、控制方法和电机驱动部分作了详细的阐述和设计。
压差检测部分主要任务是完成非电量到电量的转换,使用电容式压差变送器将流量计入口和出口的压差信号△P转换成标准的4～20mA的电流信号输出。信号采集与转换部分主要完成功率放大和A/D转换,由美国ATMEL公司生产的AT89C51AC2微处理器实现。在电机驱动部分的分析中使用步进电机作为执行机构,设计了步进电机驱动器和功率放大器。另外,抗干扰设计保证了系统的安全性和稳定性。控制方法是本文的重点内容,在分析了流体控制领域常用的几种控制方法,比较了各自的优缺点之后,选择了结合常规PID控制和模糊控制的新的控制策略—模糊自整定PID控制,这种复合型控制方式既能充分体现PID控制的结构简单、控制精度高和稳态无误差的优点,又可以充分发挥模糊控制的动态性能好和擅长解决非线性问题方面的特长。在控制器的变量和变量隶属度确定之后,给出了控制规则表,应用MATLAB仿真软件对控制过程进行了仿真,仿真结果表明所设计的控制系统能取得良好的控制性能。
Liquid flow is an important parameter of industry. Along with the fast development of modern industrial technology, and the measuring environment complicates day by day, the requirement of flow measurement comes higher and higher, many technical problems await to be solved, measuring precision is one of the keys. For liquid low flow measurement of volumetric flowmeter, the erroris mainly from leakage.
In this thesis, the error characteristics were analyzed firstly, and a full new measuring method, differential-pressure compensation method, is arising to improve the measuring precision according to the principle of hydromechanics. And it elaborates the design idea and integrating the theory of examination and control, provides the construction of examination and test system. And then, it gives detailed illustration and design of the partials of the system, differential pressure examination and test, signal gathering and transforming, controlling method and motor driving.
The function of differential pressure examination and test part is to complete the transformation from non-electric signal to electric signal. Using capacitive differential pressure transformer, the differential pressure△P between entrance and exit of flowmeter is transformed to a standard electric current signal in 4~20mA for output. The function of the signal gathering and transforming is power amplifying and A/D transformation, processed by AT89C51AC2 CPU of ATMEL USA. The thesis analyses the motor driving part, by step-motor, designs the step-motor driver and its power amplifier. Moreover, the anti-jamming design guarantees the system's security and stability. The control method is the keystone in this thesis. After analyzing several regular control methods in fluid control field and contrasting their advantage and shortcoming, a new fuzzy self-adjusting PID control method, united the advantages of normal PID control and fuzzy control, comes out. It owns not only the advantages, simple structure, high precision and no error of normal PID control, but also the advantages, excellent dynamic and non-linear performance of fuzzy control. Once the variable and relation to it are made certain, the control table comes out. The simulating result by MATLAB shows the good control performance of this control system.
本文首先分析了容积式流量计误差的特性,根据流体力学原理,提出了一种提高容积式流量计液体小流量测量精度的新方法—差压补偿法,阐述了差压补偿法的设计思想,即在流量计的转轴上增加一个起补偿作用的控制电机,控制电机通过定比传动与流量计的转子连接,其转速由流量计入口与出口的压差决定,使流量计转子的转速紧随压差的变化自动调节。结合检测与控制理论,给出了检测系统的总体设计方案。然后,分别对本检测系统的几个组成部分:压差检测、信号采集与转换、控制方法和电机驱动部分作了详细的阐述和设计。
压差检测部分主要任务是完成非电量到电量的转换,使用电容式压差变送器将流量计入口和出口的压差信号△P转换成标准的4～20mA的电流信号输出。信号采集与转换部分主要完成功率放大和A/D转换,由美国ATMEL公司生产的AT89C51AC2微处理器实现。在电机驱动部分的分析中使用步进电机作为执行机构,设计了步进电机驱动器和功率放大器。另外,抗干扰设计保证了系统的安全性和稳定性。控制方法是本文的重点内容,在分析了流体控制领域常用的几种控制方法,比较了各自的优缺点之后,选择了结合常规PID控制和模糊控制的新的控制策略—模糊自整定PID控制,这种复合型控制方式既能充分体现PID控制的结构简单、控制精度高和稳态无误差的优点,又可以充分发挥模糊控制的动态性能好和擅长解决非线性问题方面的特长。在控制器的变量和变量隶属度确定之后,给出了控制规则表,应用MATLAB仿真软件对控制过程进行了仿真,仿真结果表明所设计的控制系统能取得良好的控制性能。
Liquid flow is an important parameter of industry. Along with the fast development of modern industrial technology, and the measuring environment complicates day by day, the requirement of flow measurement comes higher and higher, many technical problems await to be solved, measuring precision is one of the keys. For liquid low flow measurement of volumetric flowmeter, the erroris mainly from leakage.
In this thesis, the error characteristics were analyzed firstly, and a full new measuring method, differential-pressure compensation method, is arising to improve the measuring precision according to the principle of hydromechanics. And it elaborates the design idea and integrating the theory of examination and control, provides the construction of examination and test system. And then, it gives detailed illustration and design of the partials of the system, differential pressure examination and test, signal gathering and transforming, controlling method and motor driving.
The function of differential pressure examination and test part is to complete the transformation from non-electric signal to electric signal. Using capacitive differential pressure transformer, the differential pressure△P between entrance and exit of flowmeter is transformed to a standard electric current signal in 4~20mA for output. The function of the signal gathering and transforming is power amplifying and A/D transformation, processed by AT89C51AC2 CPU of ATMEL USA. The thesis analyses the motor driving part, by step-motor, designs the step-motor driver and its power amplifier. Moreover, the anti-jamming design guarantees the system's security and stability. The control method is the keystone in this thesis. After analyzing several regular control methods in fluid control field and contrasting their advantage and shortcoming, a new fuzzy self-adjusting PID control method, united the advantages of normal PID control and fuzzy control, comes out. It owns not only the advantages, simple structure, high precision and no error of normal PID control, but also the advantages, excellent dynamic and non-linear performance of fuzzy control. Once the variable and relation to it are made certain, the control table comes out. The simulating result by MATLAB shows the good control performance of this control system.
引文
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[3]赵彩琳.流量计的选型及应用[J].科技情报开发与经济,2005,15(24):241-243
[4]蔡武昌.流量测量仪表现状和发展动向[J].自动化仪表,1996,17(3):7-10
[5]纪纲.流量测量仪表应用技巧[M].北京:化学工业出版社,2003:3-6
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[7]梁国伟,蔡武昌.流量测量技术及仪表[M].北京:机械工业出版社,2002:262-287
[8]朱德祥,张廷柱,朱福茂.流量仪表原理和应用[M].上海:华东化工学院出版社,1992:65-75
[9]蔡武昌,孙淮清.流量测量方法和仪表选用讲座[J].自动化仪表,1998,(6):43-46
[10]李玉柱,苑明顺.流体力学[M].北京:高等教育出版社,2002:25-35
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[12]周世民.容积式流量计误差特性分析[J].黑龙江石油化工,1996,(1):33-43
[13]荆荣霞,万金领,田晓娟.差压补偿法在提高容积式流量计测量精度方面的应用[J].机械与电子,2007,(1):49-51
[14]单成祥.传感器的理论与设计基础及其应用[M].北京:国防工业出版社,1999:25-75
[15]吴勤勤.控制仪表及装置[M].北京:化学工业出版社,2004:49-59
[16]史维祥.流体传动及控制的现状及新发展[J].流体传动与控制,2004,(1):9-15
[17]黄赞,陈伟文.模糊自整定PID控制器的设计及其MATLAB仿真[J].控制与检测,2006,(2):50-52
[18]张强.智能型气液增力系统位置控制的研究[D].济南:山东轻工业学院,2006
[19]Shin M.C.,Huang Y.F..Pneumatic Servo-Cylinder Position Control Using a self-turing Controller[J].JSME,Series C.1992,35(2):88-108
[20]Bose B.k..Expert system,fuzzy logic and neural network applications in power electronics and motion Control[A].proceeding of the IEEE[C],1994,13(3):1303-1323
[21]Xue Yang,Peng Guang-zheng,Fan Meng.New Asymmetric Fuzzy PID Control for Pneumatic Position Control System[J].Journal of Beijing Institute of Technology,2004,13(1):29-30
[22]Rahman M.A.,Honque M.A..On-line Adaptive Artificial Neural Network Based Vector Control of Permanent Magnet Synchronous Motors[J],IEEE Transaction on Energy Conversion,1998,13(4):37-40
[23]Touati Y.,Djouani K..Neuro-fuzzy based approach for hybrid force/position robot control[J].Integrated computer-Aided Enginaeering,2004,(11):85-98
[24]Huang S.N.,Tan K.K.,Lee T.H..Adaptive motion control using neural netwo- rk approximations[J].Automatica,2002,38(2):227-233
[25]Basterretxea K.,Tarela J.M.,DelCampo I..Digital design of sigmoid approxi- mator for artificial neural networks[J].Electronics Leters,2002,38(1):35-37
[26]陶永华.新型PID控制及其应用[M].北京:机械工业出版社,2002:101-105
[27]陈东,姚成法.基于LabVIEW步进电机PID控制系统的设计[J].工业仪表与自动化装置,2005,(1):48-49
[28]钱平.伺服系统[M].北京:机械工业出版社,2005:46-74
[29]曾庆勇.微弱信号检测[M].杭州:浙江大学出版社,1993:38-47
[30]刘金琨.先进PID控制MATLAB仿真(第二版)[M].北京:电子工业出版社,2006:2-28
[31]于生海等.微型计算机控制技术[M].北京:清华大学出版社,1996:75-98
[32]李士勇.模糊控制神经控制和智能控制论[M].哈尔滨:哈尔滨工业大学出版社,1996:250-280
[33]曾光奇,胡均安.模糊控制理论与工程应用[M].武汉:华中科技大学出版社,2006:85-94
[34]张国良,曾静.模糊控制及其MATLAB应用[M].西安:西安交通大学出版社,2002:14-40
[35]武红幸,虞鹤松.FUZZY CONTROLLER算法研究[J].热力发电,2003,(2):41-44
[36]候勇严,郭文强.一种模糊PID控制器的设计方法研究[J].陕西科技大学学报,2005,(9):87-89
[37]邵红,李川香.一种基于Fuzzy-PID的温度控制系统[J].自动化仪表,2002,23(9):70-72
[38]刘国光.基于模糊算法的自适应温度控制器[J].仪器仪表,2002,9(2):9-11
[39]Pivonka P.Comparative analysis of fuzzy PI/PD/PID controller base on classicl PID controller approach[A].Proceedings of the 2002 IEEE International Co- nference on Fuzzy systems[C],2002,(8):541-546
[40]George K.I..Analysis of direct action fuzzy PID controller structures[A].IEEE Transactions on Systems,Man,and Cybernetics,Part B:Cybernetics[C],1999,29(3):371-387
[41]Zhao Z.Y.,Tomizuka M.,Isaka S..Fuzzy gain scheduling of PID Controllers [A].IEEE Transactions on Systems,Man,and Cybernetics[C],1993,(23):1392-1398
[42]李汉舟,杨世超.基于模糊PID的直流力矩电机转速控制[J].中国惯性技术学报,2002,12(6):79-82
[43]肖其军,李胜勇.模糊自整定PID控制器的设计以及MATLAB仿真分析[J].计算机仿真分析,2005,22(9):242-244
[44]康严文,李智勇,王维庆.基于MATLAB的风能自校正自整定PID模糊控制器的仿真研究[J].水力发电,2006,32(1):61-91
[45]黄赞,陈伟文.模糊自整定PID控制器设计及其MATLAB仿真[J].控制与检测,2006,(2):50-52
[46]储月娥,吕宗伟.模糊控制器的设计原理及其应用[J].自动化与仪表,2005,(5):84-87
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[2]程斌,杨尚平,马骏骑,赵斌.浅谈我国流量测量研究的现状[J].中国仪器仪表,2005,(10):42-45
[3]赵彩琳.流量计的选型及应用[J].科技情报开发与经济,2005,15(24):241-243
[4]蔡武昌.流量测量仪表现状和发展动向[J].自动化仪表,1996,17(3):7-10
[5]纪纲.流量测量仪表应用技巧[M].北京:化学工业出版社,2003:3-6
[6]杜维,张宏建,乐嘉华.过程检测技术及仪表[M].北京:化学工业出版社,1999:66-70
[7]梁国伟,蔡武昌.流量测量技术及仪表[M].北京:机械工业出版社,2002:262-287
[8]朱德祥,张廷柱,朱福茂.流量仪表原理和应用[M].上海:华东化工学院出版社,1992:65-75
[9]蔡武昌,孙淮清.流量测量方法和仪表选用讲座[J].自动化仪表,1998,(6):43-46
[10]李玉柱,苑明顺.流体力学[M].北京:高等教育出版社,2002:25-35
[11]陈彦祥,杨焕诚.液体容积式流量计漏流引起的误差分析[J].内蒙古质量技术监督,2002,(6):31-33
[12]周世民.容积式流量计误差特性分析[J].黑龙江石油化工,1996,(1):33-43
[13]荆荣霞,万金领,田晓娟.差压补偿法在提高容积式流量计测量精度方面的应用[J].机械与电子,2007,(1):49-51
[14]单成祥.传感器的理论与设计基础及其应用[M].北京:国防工业出版社,1999:25-75
[15]吴勤勤.控制仪表及装置[M].北京:化学工业出版社,2004:49-59
[16]史维祥.流体传动及控制的现状及新发展[J].流体传动与控制,2004,(1):9-15
[17]黄赞,陈伟文.模糊自整定PID控制器的设计及其MATLAB仿真[J].控制与检测,2006,(2):50-52
[18]张强.智能型气液增力系统位置控制的研究[D].济南:山东轻工业学院,2006
[19]Shin M.C.,Huang Y.F..Pneumatic Servo-Cylinder Position Control Using a self-turing Controller[J].JSME,Series C.1992,35(2):88-108
[20]Bose B.k..Expert system,fuzzy logic and neural network applications in power electronics and motion Control[A].proceeding of the IEEE[C],1994,13(3):1303-1323
[21]Xue Yang,Peng Guang-zheng,Fan Meng.New Asymmetric Fuzzy PID Control for Pneumatic Position Control System[J].Journal of Beijing Institute of Technology,2004,13(1):29-30
[22]Rahman M.A.,Honque M.A..On-line Adaptive Artificial Neural Network Based Vector Control of Permanent Magnet Synchronous Motors[J],IEEE Transaction on Energy Conversion,1998,13(4):37-40
[23]Touati Y.,Djouani K..Neuro-fuzzy based approach for hybrid force/position robot control[J].Integrated computer-Aided Enginaeering,2004,(11):85-98
[24]Huang S.N.,Tan K.K.,Lee T.H..Adaptive motion control using neural netwo- rk approximations[J].Automatica,2002,38(2):227-233
[25]Basterretxea K.,Tarela J.M.,DelCampo I..Digital design of sigmoid approxi- mator for artificial neural networks[J].Electronics Leters,2002,38(1):35-37
[26]陶永华.新型PID控制及其应用[M].北京:机械工业出版社,2002:101-105
[27]陈东,姚成法.基于LabVIEW步进电机PID控制系统的设计[J].工业仪表与自动化装置,2005,(1):48-49
[28]钱平.伺服系统[M].北京:机械工业出版社,2005:46-74
[29]曾庆勇.微弱信号检测[M].杭州:浙江大学出版社,1993:38-47
[30]刘金琨.先进PID控制MATLAB仿真(第二版)[M].北京:电子工业出版社,2006:2-28
[31]于生海等.微型计算机控制技术[M].北京:清华大学出版社,1996:75-98
[32]李士勇.模糊控制神经控制和智能控制论[M].哈尔滨:哈尔滨工业大学出版社,1996:250-280
[33]曾光奇,胡均安.模糊控制理论与工程应用[M].武汉:华中科技大学出版社,2006:85-94
[34]张国良,曾静.模糊控制及其MATLAB应用[M].西安:西安交通大学出版社,2002:14-40
[35]武红幸,虞鹤松.FUZZY CONTROLLER算法研究[J].热力发电,2003,(2):41-44
[36]候勇严,郭文强.一种模糊PID控制器的设计方法研究[J].陕西科技大学学报,2005,(9):87-89
[37]邵红,李川香.一种基于Fuzzy-PID的温度控制系统[J].自动化仪表,2002,23(9):70-72
[38]刘国光.基于模糊算法的自适应温度控制器[J].仪器仪表,2002,9(2):9-11
[39]Pivonka P.Comparative analysis of fuzzy PI/PD/PID controller base on classicl PID controller approach[A].Proceedings of the 2002 IEEE International Co- nference on Fuzzy systems[C],2002,(8):541-546
[40]George K.I..Analysis of direct action fuzzy PID controller structures[A].IEEE Transactions on Systems,Man,and Cybernetics,Part B:Cybernetics[C],1999,29(3):371-387
[41]Zhao Z.Y.,Tomizuka M.,Isaka S..Fuzzy gain scheduling of PID Controllers [A].IEEE Transactions on Systems,Man,and Cybernetics[C],1993,(23):1392-1398
[42]李汉舟,杨世超.基于模糊PID的直流力矩电机转速控制[J].中国惯性技术学报,2002,12(6):79-82
[43]肖其军,李胜勇.模糊自整定PID控制器的设计以及MATLAB仿真分析[J].计算机仿真分析,2005,22(9):242-244
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