水下液壓沖擊鏟控制系統(tǒng)

1、JMarineSciAppl(2008)7：139142DOI：10 1007s1180400860460水下液壓沖擊鏟控制系統(tǒng)劉賀平，羅阿妮，肖海燕機械與電氣工程學(xué)院，哈爾濱工程大學(xué)，哈爾濱150001，中國摘要：本次設(shè)計的控制系統(tǒng)主要是確定了一個水下液壓沖擊鏟的控制效果。本文首先分析這些沖擊鏟的工作原理以及其控制系統(tǒng)的重要性。一種新的控制系統(tǒng)數(shù)學(xué)模型是根據(jù)這些原則分析和建立的。自從最初的控制系統(tǒng)的響應(yīng)時間不能滿足其設(shè)計要求之后，控制系統(tǒng)添加了PID控制器，系統(tǒng)的響應(yīng)時間仍然比要求的要慢，所以增加了神經(jīng)網(wǎng)絡(luò)到非線性調(diào)節(jié)比例元素中，即PID控制器的積分和微分環(huán)節(jié)的系數(shù)?？刂葡到y(tǒng)在得到改進之后，

2、系統(tǒng)參數(shù)就能夠符合設(shè)計要求。電控部件例如快速移動的高速開關(guān)閥的工作性能在很大程度上是由控制系統(tǒng)確定的。常規(guī)的控制方法一般不能滿足沖擊鏟的控制要求。因此在先進和常規(guī)的控制方法相結(jié)合的情況下，控制系統(tǒng)的性能得到了很大的提高，也產(chǎn)生了不錯的效果。關(guān)鍵詞：液壓沖擊鏟;控制系統(tǒng)；PID；BP網(wǎng)絡(luò)1、介紹液壓沖擊工具已經(jīng)發(fā)展了很多年，而且這種產(chǎn)品已經(jīng)得到了廣泛的應(yīng)用，相關(guān)技術(shù)也進行了深入研究，不同的材料需要不同的沖擊力，但目前液壓沖擊器的沖擊頻率無法得到驗證，因此，沖擊力所產(chǎn)生的沖擊能量與被損物所需要的能量不相匹配，這樣就導(dǎo)致了能量的浪費，因此有必要開發(fā)一種可以改變輸出能量的液壓沖擊工具。水下液壓沖擊鏟（

3、UHSS）主要是對可調(diào)節(jié)沖擊頻率特性進行了研究 ，當(dāng)功率是常數(shù)時，頻率與沖擊輸出的能量成反比。所以UHSS能夠調(diào)節(jié)沖擊能量。其控制系統(tǒng)對調(diào)節(jié)輸出頻率的功能以及在下面所進行得研究是至關(guān)重要的。2、 UHSS工作原理 UHSS 的工作原理如圖1所示，沖擊力通過活塞桿5往復(fù)移動所產(chǎn)生.真空氮氣室6與活塞桿5連接成一個高壓氮氣室。在后面的過程中，活塞桿5擠壓氮氣室6壓縮高壓氮氣，從而節(jié)約能源。在第四個步驟中，高壓氮氣與液壓進行有效的配合。高壓油進入入口I和III，入口與油箱相連，配油閥閥芯的往復(fù)移動調(diào)節(jié)入口IV，VI，II和III之間的聯(lián)系，從而調(diào)節(jié)活塞腔的壓力使氣缸往復(fù)移動形成沖擊。當(dāng)高壓

4、油進入到與油箱相連的高速轉(zhuǎn)換閥門2時，配油閥閥芯向左移動到端點（如圖11所示）。在這種情況下，入口與入口相連接，入口V與入口相連接。高壓油進入UHSS右腔后，左腔與油箱連接，使油箱壓力下降?；钊麠U向左移動，當(dāng)高壓油進入高速開關(guān)閥且調(diào)節(jié)閥2與罐體連接時，閥芯向右移動到終點。在這樣的情況下，入口與入口相連，入口與入口 相連。高壓油移動到活塞左腔，右室提供高壓油進入油箱來減少壓力，活塞桿5向右移動。在UHSS工作之前，電磁閥4 先啟動，高壓油進入缸的兩個腔體內(nèi)，以防止在起動時由于壓差太大而引起的沖擊。在最后階段，電磁閥4再次啟動，油缸兩腔內(nèi)的液壓油進入到油箱中。這種UHSS是以兩個高速開關(guān)閥控制為主

5、。其額定頻率為25Hz?？刂葡到y(tǒng)主要控制高速開關(guān)閥的運動，控制閥控制活塞的運動。如果控制系統(tǒng)不能正常工作，將直接影響活塞桿的運動。由于控制系統(tǒng)的作用非常重要，因此對其進行分析是必要的。接下來控制系統(tǒng)將在其工作原理上建立。1 2.高速轉(zhuǎn)換閥；3.電磁閥組；4油箱分配閥；5活塞桿；6.氮氣室圖1鏟工作原理3、控制系統(tǒng)模型以下為UHSS工作描述。兩個高速開關(guān)閥控制配油閥的運動。通過這種方式，高壓油的流動方向得到調(diào)整。因此，活塞桿能快速的往復(fù)移動.為了利用PWM信號驅(qū)動高速轉(zhuǎn)換閥，單片機需要發(fā)出信號，從壓力傳感器的反饋信號也是模擬信號，單片機也需要將這些信號改變?yōu)閿?shù)字參數(shù)以此作為判斷依據(jù)。單片機在計算

6、能力上欠佳，而程序輸入的修復(fù)是非常困難的。實時的使用系統(tǒng)壓力調(diào)節(jié)沖擊能，這種計算量太大，這對于使用單片來實現(xiàn)是非常困難的。所以，本控制系統(tǒng)采用主從式計算機，通過主機實現(xiàn)程序的計算，壓力傳感器將液壓系統(tǒng)的壓力反饋到副機上，從而副機能輸出 正確的控制信號，詳細的控制框架如下圖所示。圖2 UHSS控制系統(tǒng)的框架圖4、控制系統(tǒng)的分析圖3 UHSS第4組控制系統(tǒng)框圖 基于以上分析，建立了UHSS控制系統(tǒng)?？刂葡到y(tǒng)的框架在圖3上有說明。在圖中，KQ是高壓轉(zhuǎn)換閥門的流量增益，AF是閥芯兩側(cè)負載區(qū)域的差異，mF是閥芯及其內(nèi)部油的等效質(zhì)量，X是閥芯的位移，BF是閥芯阻尼系數(shù)，kF是閥芯油的等效剛度，Ct是泄漏系

7、數(shù)，A1是油缸的左腔截面面積，A2是另一腔的截面面積，V1的油缸右腔的體積?？刂葡到y(tǒng)電壓為輸入，液壓系統(tǒng)的油壓為輸出，這樣使控制模型得以建立與分析。圖4和圖5是伯德圖和開環(huán)傳遞函數(shù)的升壓反應(yīng)曲線圖，基于圖4，控制系統(tǒng)確定了幅度和相位極值，因此，該系統(tǒng)是穩(wěn)定的，但開環(huán)增益和閉環(huán)頻率帶寬是非常低的，而且響應(yīng)速度較低，如圖5，系統(tǒng)不善于跟蹤大規(guī)模調(diào)整振幅和頻率的范圍，所以適當(dāng)?shù)男Ｕ椒ê涂刂撇呗员徊捎脕硖岣呦到y(tǒng)的性能。圖4 控制系統(tǒng)的Bode圖圖5 無反饋控制系統(tǒng)的階躍曲線為了改善控制系統(tǒng)，首先PID控制被添加到控制系統(tǒng)中，比例環(huán)節(jié)，積分環(huán)節(jié)和導(dǎo)數(shù)元素系數(shù)的變化來獲得不同的控制系統(tǒng)輸出。最后，通過三

8、個系數(shù)的合理組合，可以得到所需的系統(tǒng)輸出。數(shù)個PID系數(shù)組合曲線如圖6所示，沒有標(biāo)記的曲線是PID改進前的響應(yīng)曲線。所有的曲線是階躍信號的系統(tǒng)響應(yīng)。結(jié)果如圖6所示。合理的選擇PID系數(shù)可以在一定程度上提高控制系統(tǒng)的響應(yīng)速度，但是系統(tǒng)達到穩(wěn)定的時間不能滿足需求，這樣的反應(yīng)速度不能滿足設(shè)計要求，UHSS通過判斷壓力傳感器反饋的信號來控制這些高速開關(guān)閥。不同的環(huán)境和UHSS的工作情形，系統(tǒng)的參數(shù)會有所不同。從這一點上，控制系統(tǒng)屬于隨時間變化的不確定系統(tǒng)，使用PID控制不能得到理想的結(jié)果。為了通過PID控制得到良好的控制結(jié)果，比例、積分和微分系數(shù)應(yīng)調(diào)整形成一種復(fù)雜的非線性關(guān)系。這對于PID控制來說是很

9、困難的，為了解決這些問題，神經(jīng)網(wǎng)絡(luò)理論被引入到PID控制器中，神經(jīng)網(wǎng)絡(luò)具有表達任何非線性的能力。通過研究系統(tǒng)的性能，最佳的PID控制結(jié)合可以形成。采用BP神經(jīng)網(wǎng)絡(luò)，自學(xué)式PID控制器，包括系數(shù)Kp，KI，和KD被建立。圖6 不同參數(shù)的曲線響應(yīng)圖7 基于BP網(wǎng)絡(luò)的PID控制框圖（a） 階躍響應(yīng)曲線（b）KP，KI，KD的變化曲線圖8基于BP網(wǎng)絡(luò)的PID自適應(yīng)曲線 圖7給出了基于BP網(wǎng)絡(luò)PID控制器控制系統(tǒng)的框圖。G（s）是控制系統(tǒng)的傳遞函數(shù)。改進的控制系統(tǒng)的模擬分析結(jié)果如圖8，包括系統(tǒng)的響應(yīng)曲線和控制器的三個參數(shù)的變化曲線，左圖為階躍響應(yīng)信號，右圖顯示了PID控制器三個參數(shù)曲線的變化，該控制系統(tǒng)

10、的穩(wěn)定時間在0.015s內(nèi)，過度穩(wěn)定時間低于5%，上升時間為0.006 s。因此，完善后的控制系統(tǒng)能夠滿足控制系統(tǒng)的響應(yīng)速度和穩(wěn)定性的要求，實現(xiàn)了UHSS控制系統(tǒng)。5.結(jié)論 此控制系統(tǒng)是UHSS的一個重要組成部分。是否合理將直接決定了UHSS的功能。其控制系統(tǒng)已經(jīng)進行了分析和改進研究。因此，該控制系統(tǒng)可以在給定的時間里滿足設(shè)計的要求且穩(wěn)定。隨著技術(shù)的發(fā)展，先進的控制方法逐漸被引入到控制系統(tǒng)中，以顯著的提高控制系統(tǒng)。在此期間，一些傳統(tǒng)的控制方法將會由困難變得簡單。參考文獻 1.劉賀平，孟慶鑫，房曉明 水下液壓沖擊器的機理研究期刊論文-哈爾濱工程大學(xué)學(xué)報 2005（1） 2.孟慶鑫，劉賀平，王立全

11、，張嵐，弓海霞 自反饋式水下液壓沖擊器沖擊頻率的確定期刊論文-哈爾濱工程大學(xué)學(xué)報 2005（2） 3.劉賀平 水下液壓挖掘機虛擬樣機設(shè)計及關(guān)鍵技術(shù)試驗研究D 哈爾濱工程大學(xué) 2005 4.白金，韓俊偉 基于MATLAB/Simulink環(huán)境下的PID參數(shù)整定期刊論文-哈爾濱商業(yè)大學(xué)學(xué)報（自然科學(xué)版）2007（6） 5.趙娟平，張玉俠 基于BP神經(jīng)網(wǎng)絡(luò)整定的PID控制及其方針研究期刊論文-沈陽化工學(xué)院學(xué)報 2007（2）附件：（外文翻譯原文）JMarineSciAppl(2008)7：139142DOI：10 1007s1180400860460Underwater hydraulic shoc

12、k shovel control systemLIU He-ping, LUO A-ni, XIAO Hai-yanCollege of Mechanical and Electrical Engineering,Harbin Engineering University,Harbin 150001，ChinaAbstract：The control system determines the effectiveness of an underwater hydraulic shock shovel This paper begins by analyzing the working prin

13、ciples of these shovels and explains the importance of their control systemsA new type of contr01 systems mathematical model was built and analyzed according to those principlesSince the initial control systems response time could not fulfill the design requirementsa PID controller was added to the

14、control systemSystem response time was still slower than required，so a neural network was added to nonlinearly regulate the proportional element，integral element and derivative element coefficients of the PID controllerAfter these improvements to the control system，system parameters fulfilled the de

15、sign requirementsThe working performance of electricallycontrolled parts such as the rapidly moving high speed switch valve is largely determined by the control systemNormal control methods generally cant satisfy a shovels requirementsso advanced and normal control methods were combined to improve t

16、he control systembringing good resultsKeywords:hydraulic shock shovel；control system；PID；BP network1 IntroductionThe hydraulic impact tool has been developing for many yearsMoreover,this kind of products has been widely usedRelative technology has also been deeply studiedDifferent material needs dif

17、ferent impact forceBut at present，the shock frequency of hydraulic impact tool cant be verifiedTherefore，the shock energy generated by the shock force doesnt match the one that the thing needs to be destroyed，which leads to wastage of energyIt is necessary to develop a kind of hydraulic shock tool w

18、hich can change the output energyThe underwater hydraulic shock shovel (UHSS)studied in this paper has the character of regulating impact frequencyWhen the power is constant，frequency is in inverse proportion to the output energy of one shockSo UHSS can regulate impact energyIts control system is im

19、portant to the function of regulating the output frequency and will be studied below2 UHSS work principlesThe work principle of UHSS is shown in Fig 1The shock force is produced by piston rod 5 moving To-and-froThe vacuum nitrogen chamber 6 connecting with the top of piston rod 5 is a High-pres

20、sure nitrogen chamberIn the back course， the piston rod 5 reduces the volume of nitrogen chamber 6 to compress high-pressure nitrogen and thus save energyIn the forth course，the high-pressure nitrogen works together with hydraulic pressureHigh-pressure oil enters into entrances I and III and entranc

21、e II is connected with the tankThe spool of the oil-distributing valve moves to-and-fro to regulate the relation of entrances IV,V ,I,II and III,so as to regulate the pressure of piston chambers to make the cylinder move to-and-fro and thus form shock. When high-pressure oil moves into the high-spee

22、d switch valve 2 and the valve is connected with the tank，the spool of the oil-distributing valve moves left to the endpoint(as shown in Fig1)1 Under such circumstancesentrance IV is connected with entrance II and entrance V with IIIThe high-pressure oil enters into the right chamber of UHSSand the

23、left chamber is connected with the oil tankwhich makes the chamber pressure fallThe piston rod moves left When high-pressure oil enters into the high-speed switch valve and valve 2 is connected with the tank. the spool moves to the right endpoint.Under such circumstancesentrance IV is connected with

24、 entrance l and entrance V with IIThe high-pressure oil moves into the left chamber of the pistonThe right chamber delivers high-pressure oil into the tank to reduce its pressureThe piston rod 5 moves rightBefore UHSS works，group 4 of electromagnetism valves works and high-pressure oil enters into t

25、he two chambers of the cylinder,which prevents the impulsion due to too large difference of pressure at the time of start up2 the end of work，group 4 works again and the hydraulic oil in the two chamber of the cylinder enters into the tankThis UHSS is controlled mainly by two high-speed switch valve

26、sIts rated frequency is 25 HzThe control system mainly controls the movement of the high-speed switch valve，and the valve controls the pistonIf the control system cant work normally，the movement of the piston rod is directly influencedBecause of the important role of the control systemit is necessar

27、y to analyze itThe control system will be built in the followingbased on the work principle3J1,2.high-speed switch valves；3.oildistributing valve 4a group of electromagnetic valve；5 piston rod；6nitrogen chamberFig1 Shovel work principle3 Control system modelThis UHSS works as the following descripti

28、onTwo High-speed switch valves control the motion of oil-distributing valveBy this way,the flowing direction of high pressure oil is adjustedAs a result， the piston rod moves quickly to-and-froIn order to utilize PWM signal driving the high-speed switch，a Single-chip-computer is needed to give out s

29、ignalsThe feedback signal from the pressure sensor is an analog signal tooThe single-chip-computer is also needed to change these signals into digital parameters as judgment signalsThe single-chip-computer is not good at calculation，and the programs inputted repair is very difficultUsing the system

30、pressure to adjust shock energy in real·time，and calculation is too hugeThen it is very difficult for single-chip-computer implementingSo this control system uses master and slave computers， implementing the program calculation by master computerThe press sensor feeds the oil pressure of the hy

31、draulic system back to the slave computer so that the slave computer gives out correct control signalThe detailed control framework is shown in the following Fig2Fig2 Control system framework of UHSS4 Analysis of the control systemFig3 Control system block diagram of UHSS in the forth courseBased on

32、 above analyses，the control system is built for UHSSThe control system framework is illustrated in Fig3In the figure，KQ is the flux gain of high switch valve，AF is the loading area difference on both sides of the valve spool，mF is equivalent mass of spool and its inner oil，x is the displacement of t

33、he spool，BF is the damp coefficient of spool，kF is oil equivalent stiffness in spool,Ct is leakage coefficient, A1 is the section area of the cylinders left chamber,A2 is the section area of another chamber,V1 is the volume of the cylinders right chamberThe input is voltage in the control syste

34、m and output is oil pressure of the hydraulic systemThe control model is built and analyzedFigs4 and 5 are open-loop control Bode diagram and open-loop transfer function step-up response curve respectivelyBased on Fig4，the control system has definite amplitude and phase extremum，and therefore，the sy

35、stem is steadyBut the open-loop gain and the closed-loop frequency bandwidth are very low，and response speed is low，as shown in Fig5The systemis not good at tracking because there is larger adjustment scope of amplitude and frequency， appropriate emendation method and control tactic are adopted to i

36、mprove performance of the systemFig4 Bode diagram of control systemFig5 Step curve of control system without feed-backIn order to amend the control systemfirstly the PID controller is added to the control systemProportional element， integral element and derivative element coefficients are changed to

37、 gain different control system outputsAt last，through reasonable combination of three coefficients，the required system outputs are gainedSeveral PID coefficients combination Curves are shown in Fig6The unmarked curve is the response curve before PID improvementAll the curves are system response

38、 to step signalsAnalysis results are shown in Fig6Choosing the PID coefficients reasonably could improve the control systems response speed to some extentBut the time to get stabilization is more than the required oneand such response speed could not fulfill the design requirementThe UHSS controls t

39、hese high speed on-off valves by judging the pressure-sensor feedback signalIn different work environments and UHSS work states，the system parameters would be differentFrom this point，the control system belongs to time-varying uncertain systems，and using PID controller could not get ideal results In

40、 order to get good control results by PID controller,the proportional，integral and differential coefficient should be adjusted to form a kind of complicated nonlinear relationIt is difficult for general PID controllerTo solve such problems，the neural network method is introduced to PID controll

41、erNeural network has such ability to express any nonlinearityBy studying the systems performances，the best PID control combination could be formedUsing BP network，the self-study PID controller,including coefficients KP，KI，and KD，is builtFig6 Response curves with different parametersFig7 PID control

42、block diagram based on BP network(a) Step response curve(b)Changing curves of KP，KI and KDFig7 gives the control system block diagram with PID controller，which is based on BP networkG(s) is the transfer function of the control systemSimulation analysis results of the improved control system are show

43、n in Fig8，including the system response curves and the changing curves of PID controllers three parametersLeft of the Figure is the step response signal and the right shows the changing curves of PID controllers three parametersThis control system is stable within 0.015sand overshooting is less than 5rise time is 0.006 sTherefore，after improvedthe control system can fulfill requirements of the control system response spee