液位控制系统的外文翻译

外文翻译Theliquidlevelcontrolsystembasedondde\matlab\simulinkProcesscontrolisanimportantapplicationfieldofautomatictechnology,itistopointtothelevel,temperature,flowcontrolprocessvariables,suchasinmetallurgy,machinery,chemical,electricpower,etccanbewidelyused.Especiallyliquidlevelcontroltechnologyinreallife,playedanimportantroleinproduction,forexample,thewatersupply,civilwatertoweriflowwaterlevels,canaffectpeople'slivesinwater;Industrialenterpriseswithwater,ifthedrainagewaterdrainageorcontrolledproperlyornot,inrelationtotheworkshopofcondition;Boilerdrum,ifthecontrollevelboileristoolow,canmakelevelboileroverheating,possibleaccident;Jingflow,liquidlevelcontroltowercontrolaccuracyandlevelofthecraftcaninfluencethequalityoftheproductsandthecost,etc.Intheseproductionfield,arebasicallylaborstrengthortheoperationhascertainrisknatureofwork,extremelypronetoaccidentscausedbyoperatingerror,thelosses,killingmanufacturer.Visible,inactualproduction,liquidlevelcontrolaccuracyandcontroleffectsdirectlyaffectthefactoryproductioncostandeconomicbenefitofsafetycoefficient.EvenequipmentSo,inordertoensuresafety,convenientoperation,youhavetoresearchthedevelopmentofadvancedlevelcontrolmethodsandstrategies.Thegraduationdesigntopicistheliquidlevelcontrolsystembasedondde\matlab\simulink\forcecontrol,Amongthemwascontrolledobjectfortanklevel,CommunicationmodeforDDEcommunications,Matlabismainlyusedinthesimulationtest,Andforcecontrolsoftwareusedformodeling,Thissystemmainlythroughcombinationofhardwareandsoftwaredevicetoachieveprecisecontrolofliquidlevel,Inmodernindustrylevelcontrolofimportantcomponent,itinfluenceuponproductionnotallowtoignore,inordertoensuresafetyinproductionandtheproductqualityandquantity,thelevelandperformeffectivecontrolisverynecessary,Thefollowingisadescriptionofallaspects：一PIDcontrollerAproportional–integral–derivativecontroller(PIDcontroller)isageneric.controlloopfeedbackmechanismwidelyusedinindustrialcontrolsystems.APIDcontrollerattemptstocorrecttheerrorbetweenameasuredprocessvariableandadesiredsetpointbycalculatingandthenoutputtingacorrectiveactionthatcanadjusttheprocessaccordingly.ThePIDcontrollercalculation(algorithm)involvesthreeseparateparameters;theProportional,theIntegralandDerivativevalues.TheProportionalvaluedeterminesthereactiontothecurrenterror,theIntegraldeterminesthereactionbasedonthesumofrecenterrorsandtheDerivativedeterminesthereactiontotherateatwhichtheerrorhasbeenchanging.Theweightedsumofthesethreeactionsisusedtoadjusttheprocessviaacontrolelementsuchasthepositionofacontrolvalveorthepowersupplyofaheatingelement.BytuningthethreeconstantsinthePIDcontrolleralgorithmthePIDcanprovidecontrolactiondesignedforspecificprocessrequirements.Theresponseofthecontrollercanbedescribedintermsoftheresponsivenessofthecontrollertoanerror,thedegreetowhichthecontrollerovershootsthesetpointandthedegreeofsystemoscillation.NotethattheuseofthePIDalgorithmforcontroldoesnotguaranteeoptimalcontrolofthesystemorsystemstability.Someapplicationsmayrequireusingonlyoneortwomodestoprovidetheappropriatesystemcontrol.Thisisachievedbysettingthegainofundesiredcontroloutputstozero.APIDcontrollerwillbecalledaPI,PD,PorIcontrollerintheabsenceoftherespectivecontrolactions.PIcontrollersareparticularlycommon,sincederivativeactionisverysensitivetomeasurementnoise,andtheabsenceofanintegralvaluemaypreventthesystemfromreachingitstargetvalueduetothecontrolaction.1.ControlloopbasicsAfamiliarexampleofacontrolloopistheactiontakentokeepone'sshowerwaterattheidealtemperature,whichtypicallyinvolvesthemixingoftwoprocessstreams,coldandhotwater.Thepersonfeelsthewatertoestimateitstemperature.Basedonthismeasurementtheyperformacontrolaction:usethecoldwatertaptoadjusttheprocess.Thepersonwouldrepeatthisinput-outputcontrolloop,adjustingthehotwaterflowuntiltheprocesstemperaturestabilizedatthedesiredvalue.Feelingthewatertemperatureistakingameasurementoftheprocessvalueorprocessvariable(PV).Thedesiredtemperatureiscalledthesetpoint(SP).Theoutputfromthecontrollerandinputtotheprocess(thetapposition)iscalledthemanipulatedvariable(MV).Thedifferencebetweenthemeasurementandthesetpointistheerror(e),toohotortoocoldandbyhowmuch.Asacontroller,onedecidesroughlyhowmuchtochangethetapposition(MV)afteronedeterminesthetemperature(PV),andthereforetheerror.ThisfirstestimateistheequivalentoftheproportionalactionofaPIDcontroller.TheintegralactionofaPIDcontrollercanbethoughtofasgraduallyadjustingthetemperaturewhenitisalmostright.Derivativeactioncanbethoughtofasnoticingthewatertemperatureisgettinghotterorcolder,andhowfast,andtakingthatintoaccountwhendecidinghowtoadjustthetap，Makingachangethatistoolargewhentheerrorissmallisequivalenttoahighgaincontrollerandwillleadtoovershoot.Ifthecontrollerweretorepeatedlymakechangesthatweretoolargeandrepeatedlyovershootthetarget,thiscontrolloopwouldbetermedunstableandtheoutputwouldoscillatearoundthesetpointineitheraconstant,growing,ordecayingsinusoid.Ahumanwouldnotdothisbecauseweareadaptivecontrollers,learningfromtheprocesshistory,butPIDcontrollersdonothavetheabili