外文資料翻譯---伺服閥試驗臺計算機(jī)輔助測試系統(tǒng)的研制

1、<p>　　Study on Computer Assistant Test System of ServoValve Test-bed</p><p>　　Abstract：According to the need of the static and dynamic characteristics ofthe test on servo valve , firstly this article in

2、troduces the necessary part of the system-the pump station. Next, it designs the corresponding hydraulic and computer-aided test system and given the composition of software and hardware of the test system and the design

3、 process of software.In the end,we apply the designed system to actual production to prove that it achieve the requirements of the test on servo valve. </p><p>　　Key words：servo valve, test rig, CAT, dynamic

4、 and static characteristics </p><p>　　1. Introduction </p><p>　　Electro-hydraulic servo valve is the frequently-used control component in measurement and control system. Due to the wide use of e

5、lectro-hydraulic servo system in metallurgy, engineering machinery, and chemical industry, a large number of servo valves are also be applied in these industries.Affect by the facters of environmental，abrasion,aging and

6、so on,servo valve will malfunction inevitably and need repairs after using a certain time.After maintenance and repair,we must detect the servo valve </p><p>　　2.Hydraulic pump station</p><p>　　

7、Hydraulic pump station also known as the pump station is an independent hydraulic device. It offers oil according to the requirements gradually and controlls the direction, pressure and flow rate of hydraulic oil, applie

8、d to the mainframe and hydraulic devices separability of hydraulic machinery. After the purchase users just connect hydraulic station and host of implementing agencies (motor oil or fuel tanks) with tubing, and hydraulic

9、 machinery can be realize these movements and the work cycle</p><p>　　Hydraulic pump station consists of pump device, block or valve, tanks, a combination of electrical boxes.The function of each components

10、are as follows:</p><p>　　(1)Pump device is equipped with motors and pumps, is the source of power of the hydraulic station. It changes mechanical energy into hydraulic oil pressure energy.</p><p&g

11、t;　　(2)Integration block is assembled by hydraulic valve and channel body. It can adjust the direction, pressure and flow of the hydraulic oil. </p><p>　　(3)Valve portfolio plate valve is installed in the bo

12、ard and channels connect with each other after the board witch is the same as integration valve.</p><p>　　(4)Tank plate is a welding semi-closed container, and also located with oil filtering network and air

13、 filters used for oil, oil filters and cooling.</p><p>　　(5)Electrical boxes have two patterns. One designs external fuse terminal plate; The other installs a full range of electrical control.</p><

14、;p>　　Hydraulic station principle: motor driven pump rotation, and pump absorbs oil from the oil tank and changes mechanical energy into hydraulic pressure energy of the station. Hydraulic oil through manifold (or valv

15、e combinations) realizes the adjusting of direction, pressure, flow .Then through external pipe to the cylinder hydraulic machinery or motor, so as to realize the changing of the direction , the size of the force and the

16、 velocity, to promote the machinery working of all kinds. </p><p>　　3. Hydraulic testing system and testing methods </p><p>　　Test-bed can complete the test on static and dynamic characteristic

17、s of servo valve.Static characteristics of the test includes characteristics of unloaded flow, characteristics of pressure-gain, characteristics of flow-pressure and characteristics of leakage; dynamic characteristics ar

18、e mainly the test on frequency characteristics of servo valve. The above testing results of characteristics need to be drawn out in the way of graph. Figure 1 is a schematic diagram of hydraulic test system. </p>

19、<p>　　According to the testing tems ,we install the valve to be tested on the static and dynamic testing board respectively.When we execute a static test, we should close the switching valve 8, and open the valve 6

20、.On the contrary, turn on valve 8 , and turn down valve 6 when we do a dynamic test. </p><p>　　3.1 Testing method of characteristics of unloaded flow </p><p>　　Operations are as follows,when we

21、test the characteristics of unloaded flow.First,close switch valve 18 and 7, and open valve 17 and 9.We should make sure the pressure difference between the two output ports A and B of the electro-hydraulic servo valve △

22、PL=0. And then input triangle-wave current signal with the frequency of 0.01Hz into the valve being tested. The size of the current signal vary in accordance with the following rule: changes from 0 to +imax, then from +i

23、max to 0, then to +imax , </p><p>　　3.2 Test method of load-flow characteristics</p><p>　　The operations of the test on load-flow characteristics are as follows: First, open switch valve 18 and

24、9, close the valves 17 and 7, make sure the oil of port A and B flows through the one-way valve 23 and proportional relief valve 22. Proportional relief valve (minimum moderating pressure <0.5MPa) can change the load

25、pressure during the test,and the turbine flowmeter 16 can measure the flow under a variety of load operating conditions. To start the test,we should adjust the relief valve 3, mak</p><p>　　3.3 Test method of

26、 pressure characteristics </p><p>　　Before the test, closed switch valve 17,18 and 7 and open the valve 9, make sure the output flow of the valve to be tested is zero.Then adjust the pressure relief valve 3

27、so that the pressure of the system equals to the rated pressure and return oil pressure (measured by pressure sensor 13) . Then input the valve coil to be tested with a triangular wave current signal of 0.1Hz.The compute

28、r reads the value of pressure transducer 14 and 15,so we can detect the pressure difference of the two out po</p><p>　　3.4 Testing method of leakage features</p><p>　　Close switch valve 17,18 an

29、d 9,and open valve 7,then adjust the relief valve 3 to make the pressure of the system is the same as the rated pressure of the valve to be tested.Then input the valve coil with exciting current and measure the flow by f

30、low transducer 5,and input the computer with the leak signal and rated exciting current signal after sampling. Leckage curves can be sketched out by the testing system qr = f (± i) .</p><p>　　3.5 Test o

31、f dynamic characteristics</p><p>　　According to the international standard , test of dynamic characteristics of current servo valve mainly refers to width of amplitude frequency when characteristic curve of

32、amplitude frequency is -3dB and phase-frequency width when characteristic curve of phase-frequency is -90°.We should use 10 sinusoidal signals of different frequiencies for exciting signals of the valve coil to be t

33、ested ,then measure the output flow signal in turn and filter out the signals different with the exciting signal </p><p>　　When we do the test of the dynamic characteristics , close switch valve 6 and open v

34、alve 8 . An independent signal generator produces scaning sinusoidal signal . The signal is entered into the servo amplifier after amplification and drive the dynamic cylinder to move . With the help of the speed sensor

35、installed on the dynamic cylinder ,we can equate the output flow of the servo valve being tested . And the shift sensor installed on the other side can be used for preventing the dynamic cylinder </p><p>　　4

36、. Current circuit of the test system </p><p>　　The signals need to be collected during the static characteristics test of the testing system signals include Current signals of the servo valve coil to be test

37、ed, Pressure of inlet oil port , Pressure signal of load port A and B , Pressure signal of leaking mouth , Flow signal of load port A and B , Flow signal of leaking mouth . The signals need to be collected during the dyn

38、amic characteristics test include current signals of valve coil to be tested ,Voltage signal outputed by speed sensor 20</p><p>　　The amplify signals of the servo valve to be tested in the above signals are

39、current signals and the others are voltage signal . As these signals detected by the sensor usually contain noise or through modulation . So the signals should go through corresponding treatment before being inputed into

40、 the computer , then converted into digital signals by A/D converter for further use .</p><p>　　Separate digital signal generator is used during the test ,and the signal generator use single chip microcomput

41、er 16 as its core and can produce triangle waves, sine waves, square waves, linear sweep sine wave signals with the frequency of 0～800HZ and so on for servo valve testing . Signal generator communicate with the main comp

42、uter by RS232 . During the test , the main computer tell signal generator the parameters such as generative type of waveform , amplitude and frequency of waveform . Sign</p><p>　　5. Software of testing syste

43、m </p><p>　　The main function of the software system is to complete the disposition of measured data and draw the testing curve . So the system can be divided into signal processing module , data communicati

44、on module , interface management module and auxiliary function modules responsible for test document processing and data storage . These modules also contain a number of sub-module respectively , and then sub-module call

45、 the function of basic library functions to complete their respective functions.</p><p>　　Signal processing module is the most important module of the test system and its sub-modules include digital filterin

46、g, curve fitting , the difference, frequency response calculation and error compensation. Algorithms can be used by digital filtering conclude median filtering , correlation filtering , limited convergence filtering and

47、so on . We can choose the appropriate filtering method according to field interfere circumstance . Least-squares principle is usually used in curve fitting to make</p><p>　　Functions of communication module

48、include read and write input/output data buffer, modules of communicate with each other of digital signal generator. Before the test , operator put needed pressure , channel of flow signal and waveform parameters of sign

49、al generator into the system .The system will call the buffer zone to establish the function and communicating functions to establish data buffering area of each channel and send parameters to the signal generator and st

50、art the D / A and A / D da</p><p>　　Interface management module is mainly responsible for the drawing of static and dynamic characteristic curves.The process is completed by esch sub-module through calling P

51、lot（）function . Auxiliary function modules includes test data formatted output to a file, and test documents and data printing . </p><p>　　The entire test system was developed under Microsoft VC6.0 , and its

52、 overall operation process is shown in Figure 3. </p><p>　　6. Examples for the test </p><p>　　Table 1 is a experimental report generated by D072-386 servo valve produced by MOOG after repair . T

53、he main pilot project results and standard specifies were list in the report . Relate curves of the testing results are not enumerate here . </p><p>　　7.Conclusion </p><p>　　The test system anl

54、ehnungs design methods of virtual instrument and bring function of software in the test into full play . The operation of the testing work is even more simple and intuitive with the maximum reduction in the use of hardwa

55、re and save the cost of servo valve test-bed . </p><p>　　伺服閥試驗臺計算機(jī)輔助測試系統(tǒng)的研制</p><p>　　摘要：根據(jù)伺服閥的動靜特性的測試要求，首先介紹了系統(tǒng)所需要的油源部分—液壓泵站，然后設(shè)計了相應(yīng)的液壓測試系統(tǒng)和計算機(jī)輔助測試系統(tǒng)，說明了測試系統(tǒng)軟硬件的組成和軟件的設(shè)計流程，最后將設(shè)計出的系統(tǒng)應(yīng)用到實際生產(chǎn)中，證明可以

56、達(dá)到伺服閥的測試要求。</p><p>　　關(guān)鍵詞：伺服閥,試驗臺,CAT，動靜態(tài)特性</p><p><b>　　1.前言</b></p><p>　　電液伺服閥是測控系統(tǒng)中常用的測控軟件，由于液壓伺服系統(tǒng)在冶金、工程機(jī)械、化工等行業(yè)中的廣泛應(yīng)用，使伺服閥也大量的被應(yīng)用在這些行業(yè)中。伺服閥在使用一定的時間后，其性能由于環(huán)境、磨損、老化等因素，

57、不可避免地會發(fā)生故障而需要維修，維修之后的伺服閥，其各種特性是否能夠達(dá)到規(guī)定的要求，則必需要通過一定的動靜態(tài)特性檢測方法檢測之后，才能得出結(jié)論。因此，許多都根據(jù)自己的需要建有獨(dú)立的伺服閥實驗臺，以下介紹的是我們單位與某高校聯(lián)合開發(fā)的基于計算機(jī)輔助測試的伺服閥實驗臺。</p><p><b>　　液壓站</b></p><p>　　液壓站又稱為液壓泵站，是獨(dú)立的液壓裝置

58、。它按逐級要求供油。并控制液壓油液的方向、壓力和流量，適用于主機(jī)與液壓裝置可分離的各種液壓機(jī)械上。用戶購后只要將液壓站與主機(jī)上的執(zhí)行機(jī)構(gòu)（油缸或馬達(dá)）用油管連接，液壓機(jī)械即可實現(xiàn)各種規(guī)定的動作和工作循環(huán)。</p><p>　　液壓站是由泵裝置、集成塊或閥組合、油箱、電氣盒組合而成。各部件的功能為：</p><p>　　(1)泵裝置 上裝有電機(jī)和油泵，是液壓站的動力源，將機(jī)械能轉(zhuǎn)化為液壓油的

59、壓力能。</p><p>　　(2)集成塊 由液壓閥及通道體組裝而成。對液壓油進(jìn)行方向、壓力和流量調(diào)節(jié)。</p><p>　　(3)閥組合 板式閥裝在立板上，板后管連接，與集成塊功能相同。</p><p>　　(4)油箱 板焊的半封閉容器，上還裝有濾油網(wǎng)、空氣濾清器等，用來儲油、油的冷卻及過濾。</p><p>　　(5)電氣盒 分兩種形

60、式。一種設(shè)計外接引線的端子板；一種配置了全套控制電器。</p><p>　　液壓站的工作原理：電機(jī)帶動油泵轉(zhuǎn)動，泵從油箱中吸油供油，將機(jī)械能轉(zhuǎn)化為液壓站的壓力能，液壓油通過集成塊（或閥組合）實現(xiàn)了方向、壓力、流量調(diào)節(jié)后經(jīng)過外接管路并至液壓機(jī)械的油缸或馬達(dá)中，從而實現(xiàn)控制液動機(jī)方向的變換、力量的大小及速度的快慢，推動各種液壓機(jī)械做功。</p><p>　　3.液壓測試系統(tǒng)及測試方法</

61、p><p>　　實驗臺可以完成伺服閥的動靜態(tài)特性測試：靜態(tài)特性測試的內(nèi)容包括空載流量特性、壓力增益特性、流量-壓力特性、匯漏特性；動態(tài)特性主要是伺服閥頻率特性的測試。以上特性的測試結(jié)果需要以圖形的方式繪制出來。</p><p>　　圖一是測試系統(tǒng)的液壓原理圖。</p><p>　　測試時根據(jù)測試項目，分別將被試閥安裝在動靜態(tài)測試閥板上，在做靜態(tài)測試時，將開關(guān)閥8關(guān)閉，將

62、閥6打開；在做動態(tài)測試時，則將開關(guān)閥8打開，將閥6關(guān)閉。</p><p>　　3.1空載流量特性測試方法</p><p>　　測試空載流量特性時，其操作如下：先將開關(guān)閥18、7關(guān)閉，打開閥17、9，使被試電液伺服閥的兩輸出口A、B之間的壓差△PL=0。然后向被測試閥通入頻率為0.01Hz的三角波電流信號，電流信號的大小按照以下規(guī)律變化：即由0變到+imax，再由+imax變到0，再到－im

63、ax，然后再回到0。由渦輪流量計16檢測電流變化過程中的流量，并將測得的流量值和輸入的相應(yīng)電流值送到計算機(jī)中去，由計算機(jī)可以畫出流量電流變化的，即為被試閥的空載流量特性曲線±q=f(±i)△pL=0。并可以根據(jù)測得的數(shù)據(jù)計算出閥的流量增益、對稱性、零漂和滯環(huán)等重要性能。</p><p>　　3.2負(fù)載流量特性測試方法</p><p>　　測試負(fù)載流量特性的操作如下：先將

64、開關(guān)閥18、9打開，關(guān)閉閥17、7，使測試時A、B兩口的油液通過單向閥組23和比例溢流閥22。用比例溢流閥（最低可調(diào)節(jié)壓力<0.5MPa）可以測試時負(fù)載壓力，用渦輪流量計16可以測量各種負(fù)載工況下的流量。測試時，先調(diào)節(jié)溢流閥3，使系統(tǒng)的壓力為被試電液伺服閥的額定壓力，再向被試閥線圈輸入頻率為0.1Hz的三角波電流信號，然后通過控制比例溢流閥22使負(fù)載壓力從零按一定增量逐漸變化到額定壓力，測量每一增量下的流量，輸入到計算機(jī)中。再改變

65、輸入電流的幅值（頻率不變），重復(fù)以上過程，可測得多組曲線，此即為電液伺服閥的負(fù)載流量特性曲線±q=f(±△pL)i=Cont。</p><p>　　3.3壓力特性測試方法</p><p>　　測試時先將開關(guān)閥17、18、7都關(guān)閉，打開閥9，使被試閥的輸出流量為零，然后調(diào)節(jié)溢流閥3使系統(tǒng)壓力等于被試閥的額定壓力與回油壓力（由壓力傳感器13測得）之和。然后向被試閥線圈通入0

66、.1Hz三角波電流信號，由計算機(jī)讀取壓力傳感器14、15的值，即可測出伺服閥兩輸出口之間的壓力差。改變輸入電流信號的幅值，可測得不同電流幅值下的壓差值。根據(jù)電流值和壓差值可以繪出被試閥的壓力增益特性曲線±△pL=f(±i)q=0。 3.4泄露特性測試方法</p><p>　　測試泄露特性時先將開關(guān)閥17、18、9關(guān)閉，將閥7打開，然后調(diào)節(jié)溢流閥3使系統(tǒng)壓力達(dá)到被試閥的額定壓力，然后向被試閥線圈

67、通入激勵電流，用流量傳感器5測試泄流流量的大小，并將泄露信號和給定的激勵電信號經(jīng)采樣輸送到計算機(jī)，由測試系統(tǒng)繪出泄露特性曲線qr=f(±i)。</p><p><b>　　3.5動態(tài)特性測試</b></p><p>　　根據(jù)國際，電流伺服閥的動態(tài)特性測試主要是指其幅頻特性曲線-3dB時的幅頻寬和相頻特性曲線-90°時的相頻寬。測試時需要用10個不同

68、頻率的正弦信號作為被試閥線圈的激勵信號，然后依次測量其輸出的流量信號，并濾除流量信號中與激勵信號頻率不同的成分后作為被試伺服閥的響應(yīng)信號。這兩個信號經(jīng)采樣分別輸入到計算機(jī)，由系統(tǒng)測試軟件求出激勵信號的自功率譜GXX(f)和激勵信號與響應(yīng)信號的互功頻率GXY(f)，由此可以得頻率響應(yīng)H(f)= GXX(f)/GXY(f)。</p><p>　　動態(tài)特性測試時先將開關(guān)閥6關(guān)閉，將閥8打開，由獨(dú)立的信號發(fā)生器產(chǎn)生掃頻正

69、弦信號，經(jīng)放大之后，輸入到伺服放大器，使動態(tài)缸產(chǎn)生運(yùn)動，根據(jù)安裝在動態(tài)缸上的速度傳感器，可以求出被試伺服閥的輸出流量。而安裝在另一端的位移傳感器可以用于防止動態(tài)缸偏離中心位置。</p><p>　　4.測試系統(tǒng)電路結(jié)構(gòu)</p><p>　　測試系統(tǒng)在靜態(tài)特性試驗時需要采集的信號包括：被試伺服閥線圈的電流信號、進(jìn)油口P的壓力、負(fù)載A口和B口的壓力信號、泄漏口O的壓力信號、負(fù)載A口和B口之間的

70、流量信號、泄漏口O的流量信號；動態(tài)特性測試時需要采集的信號有：被試閥線圈的電流信號，速度傳感器20輸出的電壓信號。測試系統(tǒng)輸出的控制信號包括比例溢流閥的壓力設(shè)定值、信號發(fā)生器產(chǎn)生的被試閥線圈激勵信號。</p><p>　　以上信號中的被試閥伺服放大信號為電流信號，其他信號為電壓信號。由于傳感器檢測的這些信號通常包含有噪聲或經(jīng)過了調(diào)制，在輸入到測試計算機(jī)之前，都需要經(jīng)過相應(yīng)的處理，然后才經(jīng)過A/D轉(zhuǎn)換成數(shù)字信號，供

71、計算機(jī)作進(jìn)一步使用。</p><p>　　測試中采用獨(dú)立的數(shù)字信號發(fā)生器，該信號發(fā)生器由16單片機(jī)作為核心，可以產(chǎn)生頻率為0～800Hz的三角波、正弦波、方波、線性掃描正弦波等多種波信號，供伺服閥測試使用。信號發(fā)生器通過RS232與主計算機(jī)通信，測試時由主計算機(jī)將生成波形的類型、波形的幅值和頻率等參數(shù)告知信號發(fā)生器，信號發(fā)生器生成規(guī)定的波形之后，輸入到被試閥的伺服放大器中。在動態(tài)特性測試時，同時將生成的波形信號數(shù)

72、據(jù)傳送給主機(jī)，供計算機(jī)動態(tài)特性使用。測試系統(tǒng)的電路結(jié)構(gòu)如圖二所示。</p><p><b>　　5.測試系統(tǒng)軟件</b></p><p>　　軟件系統(tǒng)的主要功能是完成測數(shù)據(jù)的處理和測試曲線的繪制，因此從功能上劃分，可分為信號處理模塊、數(shù)據(jù)通訊模塊、界面管理模塊和負(fù)責(zé)測試文檔處理及數(shù)據(jù)保存的輔助功能模塊。這些模塊又分別包含有多個子模塊，子模塊再調(diào)用基本的函數(shù)庫函數(shù)，完成

73、各自的功能。</p><p>　　信號處理模塊是測試系統(tǒng)最重要的模塊，其子模塊包括數(shù)字濾波、曲線擬合及差值、頻響計算、誤差補(bǔ)償?shù)?。?shù)字濾波可以采用的算法有中值濾波、相關(guān)濾波、限輻濾波等方法，可以根據(jù)現(xiàn)場干擾情況選擇合適的濾波方法。曲線擬合采用常用的最小二乘法原則，使擬合后的曲線點(diǎn)的誤差平方和最小。頻響計算主要包括自相關(guān)計算和互相關(guān)計算，相關(guān)計算采用快速傅里葉變換和反變換實現(xiàn)的快速相關(guān)算法。</p>

74、<p>　　通訊模塊的功能包括讀寫輸入/輸出數(shù)據(jù)緩沖區(qū)、數(shù)字信號發(fā)生器相互通訊模塊。在測試之前，由操作人員根據(jù)測試項目，將需要采集的壓力、流量信號的通道信號，信號發(fā)生器的波形參數(shù)輸入到系統(tǒng)，系統(tǒng)將調(diào)用緩沖區(qū)建立函數(shù)和通訊函數(shù)建立個通道的數(shù)據(jù)緩沖區(qū)，并向信號發(fā)生器輸發(fā)出參數(shù)，同時啟動D/A和A/D數(shù)據(jù)轉(zhuǎn)換，各通道采用中斷方式向緩沖區(qū)寫入數(shù)據(jù)，CPU每隔1s時間讀取各緩沖區(qū)數(shù)據(jù)，在對數(shù)據(jù)進(jìn)行處理后調(diào)用界面管理模塊刷新輸出界面。&l

75、t;/p><p>　　界面管理模塊主要負(fù)責(zé)靜動態(tài)特性曲線的繪制，由個特性曲線子模塊調(diào)用Plot( )函數(shù)完成，輔助功能模塊包括測試數(shù)據(jù)的格式化輸出到文件，以及測試文檔和數(shù)據(jù)的打印。</p><p>　　整個測試系統(tǒng)采用微軟公司的VC6.0開發(fā)，其總體操作流程如圖三所示。</p><p><b>　　6.測試舉例</b></p><

76、;p>　　表一是MOOG公司生產(chǎn)的D072-386伺服閥經(jīng)維修后的檢測生成的實驗報告，報告中列出了伺服閥的主要實驗項目結(jié)果和標(biāo)準(zhǔn)規(guī)定的值，測試結(jié)果的相關(guān)曲線，在此不再一一列舉。</p><p><b>　　7.結(jié)論</b></p><p>　　該測試系統(tǒng)借鑒了虛擬儀器的設(shè)計方法，充分發(fā)揮了軟件在測試系統(tǒng)中的功能，使測試工作的操作更加簡單直觀，同時最大限度的減少了