自動(dòng)化專業(yè)英文P2U1英文全文帶翻譯課件

自動(dòng)化專業(yè)英語(yǔ)教程教學(xué)課件July28,2007Email:wanghongwen@http://P2U1ATheWorldofControl第二部分第一單元課文A控制的世界P2U1ATheWorldofControl第二部分第一單元課文A控制的世界P2U1ATheWorldofControl第二部分第一單元課文A控制的世界P2U1ATheWorldofControl第二部分第一單元課文A控制的世界P2U1ATheWorldofControl第二部分第一單元課文A控制的世界[1]ThereactiontimeofahumanpilotistooslowtoenablehimorhertoflyanaircraftwithalightlydampedDutchrollmodewithoutayawdampersystem.飛行員的反應(yīng)速度太慢，如果不附加阻尼偏航系統(tǒng)，飛行員就無(wú)法通過(guò)輕微阻尼的側(cè)傾轉(zhuǎn)向方式來(lái)駕駛飛機(jī)。[2]Sincetheoutputisfedbackinafunctionalformdeterminedbythenatureofthefeedbackelementsandthensubtractedfromtheinput…因?yàn)檩敵鰰?huì)以由反饋部件特性決定的函數(shù)形式反饋回來(lái)，然后從輸入中減去……aboundin盛產(chǎn)于abstract抽象的TheWorldofControlIntroductionThewordcontrolisusuallytakentomeanregulate,direct,orcommand.Controlsystemsaboundinourenvironment.Inthemostabstractsenseitispossibletoconsidereveryphysicalobjectasacontrolsystem..控制的世界簡(jiǎn)介控制一詞的含義一般是調(diào)節(jié)、指導(dǎo)或者命令?？刂葡到y(tǒng)大量存在于我們周圍。在最抽象的意義上說(shuō)，每個(gè)物理對(duì)象都是一個(gè)控制系統(tǒng)。Controlsystemsdesigendbyhumansareusedtoextendtheirphysicalcapabilities,tocompensatefortheirphysicallimitations,torelievethemofroutinetasks,ortosavemoney.控制系統(tǒng)被人們用來(lái)擴(kuò)展自己的能力，補(bǔ)償生理上的限制，或把自己從常規(guī)、單調(diào)的工作中解脫出來(lái)，或者用來(lái)節(jié)省開(kāi)支。extend延伸/擴(kuò)展physicalcapabilities身體能力routine例行公事compensatefor補(bǔ)償Inamodernaircraft,forexample,thepowerboostcontrolsamplifytheforceappliedbythepilottomovethecontrolsurfacesagainstlargeaerodynamicforces.ThereactiontimeofahumanpilotistooslowtoenablehimorhertoflyanaircraftwithalightlydempedDutchrollmodewithouttheadditionofyawdeampersystems.例如在現(xiàn)代航空器中，功率助推裝置可以把飛行員的力量放大，從而克服巨大的空氣阻力推動(dòng)飛行控制翼面。飛行員的反應(yīng)速度太慢，如果不附加阻尼偏航系統(tǒng)，飛行員就無(wú)法在輕微的飄擺效應(yīng)下完成飛機(jī)的駕駛。powerboost功率推助裝置Dutchrollmode飄擺效應(yīng)aerodynamic空氣動(dòng)力學(xué)Anautopilot(flightcontrolsystem)relievesthepilotofthetaskofcontinuouslyoperatingthecontrolstomaintainthedesiredheading,altitued,andatitude.Freedofthisroutinetask,thepilotcanperformothertasks,suchasnavigationand/orcommunications,thusreducingthenumberofcrewrequiredandconsequentlytheoperatingcostoftheaircarft自動(dòng)飛行控制系統(tǒng)把飛行員從保持正確航向、高度和姿態(tài)的連續(xù)操作任務(wù)中解脫出來(lái)。沒(méi)有了這些常規(guī)操作，飛行員可以執(zhí)行其他的任務(wù)，如領(lǐng)航或通訊，這樣就減少了所需的機(jī)組人員，降低了飛行費(fèi)用。navigation航行heading航向altitued高度atitude姿態(tài)consequently當(dāng)然的crew機(jī)組人員Inmanycases,thedesignofcontrolsystemisbasedonsometheoryratherthanintuitionortrail-and-error.Controltheoryisusedfordealingwiththedynamicresponseofasystemtocommands,regulations,ordisturbances.在很多情況下，控制系統(tǒng)的設(shè)計(jì)是基于某種理論，而不是靠直覺(jué)或試湊法。控制系統(tǒng)能夠用來(lái)處理系統(tǒng)對(duì)命令、調(diào)節(jié)或擾動(dòng)的動(dòng)態(tài)響應(yīng)。intuition直覺(jué)dynamic動(dòng)態(tài)的commands命令regulations調(diào)整disturbances擾動(dòng)Theapplicationofcontroltheoryhasessentiallytwophases:dynamicanalysisandcontrolsystemdesign.Theanalysisphaseisconcernedwithdeterminationoftheresponseofaplant(thecontrolledobject)tocommands,disturbances,andchangesintheplantparameters.控制理論的應(yīng)用基本上有兩個(gè)方面：動(dòng)態(tài)響應(yīng)分析和控制系統(tǒng)設(shè)計(jì)。系統(tǒng)分析關(guān)注的是命令、擾動(dòng)和系統(tǒng)參數(shù)的變化對(duì)被控對(duì)象響應(yīng)的決定作用。phases方法isconcernedwith與…相關(guān)Parameters參數(shù)satisfactory令人滿意的modification修正、改良Ifthedynamicresponseissatisfactory,thereneedbenosecondphase.Ifthereponseisunsatisfactoryandmodificationoftheplantisunaccptable,adesignphaseisnecessarytoselectthecontrolelements(thecontroller)neededtoimprovethedynamicperformancetoacceptablelevels.如某動(dòng)態(tài)響應(yīng)是滿足需要的，就不需要第二步了。如果系統(tǒng)不能滿足要求，而且不能改變被控對(duì)象，就需要進(jìn)行系統(tǒng)設(shè)計(jì)，來(lái)選擇使動(dòng)態(tài)性能達(dá)到要求的控制元件。categories類型becharacterizedby..的特點(diǎn)在于Controltheoryitselfhastwocategories:classicalandmodern.Classicalcontroltheory,whichhaditsstartduringWordWarII,canbecharacterizedbythetransferfunctionconceptwithanalysisanddesignprincipallyintheLaplaceandfrequencydomains.控制理論本身分成兩個(gè)部分：經(jīng)典和現(xiàn)代。經(jīng)典控制理論始于二次大戰(zhàn)以傳遞函數(shù)的概念為特征，分析和設(shè)計(jì)主要在拉普拉斯域和頻域內(nèi)進(jìn)行。arisen出現(xiàn)emphasison著重，強(qiáng)調(diào)Moderncontroltheoryhasarisenwiththeadventofhigh-speeddigitalcomputersandcanbecharacterizedbythestatevariableconceptwithemphasisonmatrixalgebarandwithanalysisanddesignprincipallyinthetimedonmain.Asmightbeexpected,eachapproachhasitsadvantagesanddisadvantagesaswellasitsproponentsanddetractors.現(xiàn)代控制理論是隨著高速數(shù)字計(jì)算機(jī)的出現(xiàn)而發(fā)展起來(lái)的。它以狀態(tài)變量的概念為特征，重點(diǎn)在于矩陣代數(shù)，分析和設(shè)計(jì)主要在時(shí)域。每種方法都有其優(yōu)點(diǎn)和缺點(diǎn)，也各有其倡導(dǎo)者和反對(duì)者。tutorialadvantage指導(dǎo)性優(yōu)點(diǎn)adequate勝任、足夠Ascomparedtomodernapproach,theclassicalapproachhasthetutorialadvantageofplacinglessemphasisonmathematicaltechniquesandmoreemphasisonphysicalunderstanding.Furthermore,inmanydesignsituationstheclassicalapproachisnotonlysimplerbutmaybecompletelyadequate.與現(xiàn)代控制理論相比，經(jīng)典方法具有指導(dǎo)性的優(yōu)點(diǎn)，它把重點(diǎn)很少放在數(shù)學(xué)技術(shù)上，而把更多重點(diǎn)放在物理理解上。而且在許多設(shè)計(jì)情況中，經(jīng)典方法既簡(jiǎn)單也完全足夠用。satisfactory令人滿意的modification修正、改良Ifthedynamicresponseissatisfactory,thereneedbenosecondphase.Ifthereponseisunsatisfactoryandmodificationoftheplantisunaccptable,adesignphaseisnecessarytoselectthecontrolelements(thecontroller)neededtoimprovethedynamicperformancetoacceptablelevels.如某動(dòng)態(tài)響應(yīng)是滿足需要的，就不需要第二步了。如果系統(tǒng)不能滿足要求，而且不能改變被控對(duì)象，就需要進(jìn)行系統(tǒng)設(shè)計(jì)，來(lái)選擇使動(dòng)態(tài)性能達(dá)到要求的控制元件。approach方法subsequent后續(xù)的Inthosemorecomplexcaseswhereitisnotadequate,theclassicalapproachsolutionmayaidinapplyingthemodernapproachandmayprovideacheckonthemorecompleteandexactdesign.Forthesereasonsthesubsequentairticleswillintroducetheclassicalapproachindetail.在那些更復(fù)雜的情況中，經(jīng)典方法雖不能滿足，但它的解可以對(duì)應(yīng)用現(xiàn)代方法起輔助作用，而且可以對(duì)設(shè)計(jì)進(jìn)行更完整和準(zhǔn)確的檢查。由于這些原因，后續(xù)的章節(jié)將詳細(xì)地介紹經(jīng)典控制理論。

ControlSystemEngineeringDesignProblemControlsystemengineeringconsistsofanalysisanddesigeofcontrolconfigurations.Analysisistheinvestigationofthepropertiesofanexistingsystem.Thedesignproblemisonechoiceandarrangementofsystemcomponentstoperformaspecifictask.控制系統(tǒng)工程設(shè)計(jì)問(wèn)題 控制系統(tǒng)工程由控制結(jié)構(gòu)的分析和實(shí)際組成。分析是對(duì)所存在的系統(tǒng)性能的研究，設(shè)計(jì)問(wèn)題是對(duì)系統(tǒng)部件的一種選擇和安排從而實(shí)現(xiàn)特定的任務(wù)。configurations結(jié)構(gòu)investigation研究existing目前存在的regulations調(diào)整disturbances擾動(dòng)specifictask特定任務(wù)Designingacontrolsystemisnotapreciseorwell-definedprocess;rather,itisasequenceofinterrelatedevents.Atypicalsequencemightbe控制系統(tǒng)的設(shè)計(jì)并不是一個(gè)精確或嚴(yán)格確定的過(guò)程，而是一系列相關(guān)事情的序列，典型的順序是：precise精確的well-defined嚴(yán)格確定sequence系列，順序interrelated關(guān)聯(lián)的Modelingoftheplant;2)Linearizationoftheplantmodel;3)Dynamicanalysisoftheplant;4)Nonlinearsimulationoftheplant;5)Establishmentofthecontrolphilosophy&strategy;6)Sslectiontheperformancecriteriaandindices;7)Designofthecontroller;8)Dynamicanalysisofthecompletesystem;9)Nonlinearsimulationofthecompletesystem;10)Selectionofthehardwaretobeused;11)Constructionandtestosthedevdlopmentsystem;12)Designoftheproductionmodel;13)Testoftheproductionmodel.Thissequenceisnotrigid,all-inclusive,ornecessarilysequential.Itisgivenheretoestablisharationaleforthetechniquesdevelopedanddiscussedinthesubsequentunits.這個(gè)順序不是固定的，全包括的或必要次序的。這里給出為后續(xù)單元提出和討論的技術(shù)做一個(gè)合理的闡述。

rigid固定的all-inclusive全部包括establish建立rationale基本原理subsequent后續(xù)的ClassifcationandTerminologyofControlSystemsControlsystemsareclassifiedintermsthatdescribeeitherthesystemitselforitsvariables:控制系統(tǒng)的分類和術(shù)語(yǔ)控制系統(tǒng)可根據(jù)系統(tǒng)本身或其參量進(jìn)行分類：subtracted減去、扣除Open-loopandclosed-loopcontrolsystems(seeFig.2-1A-1).Anopen-loopsystemisoneinwhichthecontrolactionisindependentoftheoutput.Aclosed-loopsystem,however,theinputoftheplantissomehowdependentontheactualoutputSincetheoutputisfedbackinafunctionalformdeterminedbythenatureofthefeedbackelementsandthensubtractedfromtheinput,aclosed-loopsystemisoftenreferredtoasanegativefeedbacksystemorsimplyasafeedbacksystem.開(kāi)環(huán)和閉環(huán)系統(tǒng)（如圖2-1A-1）：開(kāi)環(huán)控制系統(tǒng)是控制行為與輸出無(wú)關(guān)的系統(tǒng)。而閉環(huán)系統(tǒng)，其被控對(duì)象的輸入在某種程度上依賴于實(shí)際的輸出。因?yàn)檩敵鲆杂煞答佋Q定的一種函數(shù)形式反饋回來(lái)，然后被輸入減去。閉環(huán)系統(tǒng)通常是指負(fù)反饋系統(tǒng)或簡(jiǎn)稱為反饋系統(tǒng)。Continuous連續(xù)的discrete離散的Continuousanddiscretesystems.Thesystemthatallitsvariablesarecontinuousfunctionsoftimeiscalledcontinuous-variableoranalogsystem;thedescribingequationsaredifferentialequations.Adiscrete-variableordigitalsystemhasoneormorevariablesknownonlyatparticularinstantsoftime,asshowninFig.2-1A-2b;theequationsaredifferenceequations.連續(xù)和離散系統(tǒng)：所有變量都是時(shí)間的連續(xù)函數(shù)的系統(tǒng)稱做連續(xù)變量或模擬系統(tǒng)，描述的方程是微分方程。離散變量或數(shù)字系統(tǒng)有一個(gè)或多個(gè)只是在特殊時(shí)刻可知的變量，如圖2-1A-2b，描述方程是差分方程。analogsystem模擬系統(tǒng)digitalsystem數(shù)字系統(tǒng)particularinstants特定時(shí)刻

intervals

間隔occurnaturally隨機(jī)產(chǎn)生Ifthetimeintervalsarecontrolled,thevariablesoccurnaturally,asfromascanningradarthatobtainspositiondateonceperscanoradatechannelthattransmitsmanypiecesofinformationinturn.Adiscretevariablewillobviouslyapproachacontinuousvariableasthesamplingintervalisdecreased.Discontinuousvariable,suchasshowninFig.2-1A-2coccurin“on-off”or“bang-bang”controlsystemsandaretreatedseparatelyinasubsenquentpaper.如果時(shí)間間隔是可控的，系統(tǒng)被稱做數(shù)據(jù)采樣系統(tǒng)。離散變量隨機(jī)地產(chǎn)生，例如：為只能接受離散數(shù)據(jù)的數(shù)字計(jì)算機(jī)提供一個(gè)輸入。顯然，當(dāng)采樣間隔減小時(shí)，離散變量就接近一個(gè)連續(xù)變量。不連續(xù)的變量，如圖2-1A-2c所示，出現(xiàn)在開(kāi)關(guān)控制系統(tǒng)中。這將分別在后續(xù)的章節(jié)中討論。Linear線性的elements元件Linearandnonlinearsystems.Asystemislinearifallitselementsarelinear,andnonlinearifanyelementisnonlinear.線性和非線性系統(tǒng)：如果系統(tǒng)所有元件都是線性的，系統(tǒng)就是線性的。如果任何一個(gè)是非線性的，系統(tǒng)就是非線性的。Time–invarant時(shí)不變coefficients常數(shù)Time–invarantandtime-variantayatems.Atime-invariant(orstationary)systemisonewhoseparametersdonotvarywithtime.Theoutputofastationarysystemisindependentofthetimeaswhichaninputisapplied,andthecoefficientsofthedescribingdifferentialequationsareconstans.時(shí)變和時(shí)不變系統(tǒng)：一個(gè)時(shí)不變系統(tǒng)或靜態(tài)系統(tǒng)，其參數(shù)不隨時(shí)間變化。當(dāng)提供一個(gè)輸入時(shí)，時(shí)不變系統(tǒng)的輸出不依賴于時(shí)間。描述系統(tǒng)的微分方程的系數(shù)為常數(shù)。coefficients常數(shù)time-dependent與時(shí)間相關(guān)Atime-variant(ornonstationary)systemisasystemwithoneormoreparametersthatvarywithtime.Thetimeatwhichaninputiaappliedmustbeknown,andthecoefficientsofthedifferentialequationsaretime-dependent.如果有一個(gè)或多個(gè)參數(shù)隨時(shí)間變化，則系統(tǒng)是時(shí)變或非靜態(tài)系統(tǒng)提供輸入的時(shí)間必須已知，微分方程的系數(shù)是隨時(shí)間而變化的。Lumped集中的distributed分散的Lumpedparameteranddistributedsystems.Lumpedparametersystemsarethoseforwhichphysicalcharacteristicsareassumedtobeconcentratedinoneormore“l(fā)umps”andthusindependentofanyspatialdistribution.集中參數(shù)和分散參數(shù)系統(tǒng)：集中參數(shù)系統(tǒng)是其物理性質(zhì)被假設(shè)集中在一塊或多塊，從而與任何空間分布無(wú)關(guān)的系統(tǒng)。rigid剛性的suitablecorrections適當(dāng)修正Ineffect,bodiesareassumedrigidandtreatedaspointmassed;springsaremasslessandelectricalleadsresistanceless,orsuitablecorrectionsaremadetothesystemmassorresistance;temperaturesareuniform;etc.在作用上，物體被假設(shè)為剛性的，被作為質(zhì)點(diǎn)處理；彈簧是沒(méi)有質(zhì)量的，電線是沒(méi)有電阻的，或者對(duì)系統(tǒng)質(zhì)量或電阻進(jìn)行適當(dāng)?shù)难a(bǔ)償；溫度在各部分是一致的，等等。elastic有彈性的distributed分布Indistributedparametersystem,thecontinuousspatialdistributionofaphysicalcharacteristicistakenintoaccount.Bodiseareelastic,springshaveadistributedmass,electricalleadshaveadistributeresistance,andtemperaturesvaryacrossabody.Lumpedparamtersystemsaredescribedbyordinarydifferentialequation;whiledistributeparametersystemsaredescribedbypartialdifferentialequations.在分布參數(shù)系統(tǒng)中，要考慮到物理特性的連續(xù)空間分布。物體是有彈性的，彈簧是有分布質(zhì)量的，電線具有分布電阻，溫度在物體各處是不同的。集中參數(shù)系統(tǒng)由常微分方程描述，而分布參數(shù)系統(tǒng)由偏微分方程描述。predictable可預(yù)測(cè)的stachstic隨機(jī)的Deterministicandstochasticsystems.Asystemorvariablei