一篇机电一体化的英语论文及翻译Word文件下载.docx

一篇机电一体化的英语论文及翻译Word文件下载.docx

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Trondheim,Norway

ReceivedonDecember3,1997

ABSTRACT

Thispaperpresentsaunifiedapproachbasedonutilizingmultidimensionalarraysinordertomodelthephysicalandlogicalpropertiesofmechatronicssystems.Amechatronicssystemmodelconsistsoftwointeractingsubmodels.Asubmodelthatdescribesaspectsrelatedtoenergyflowinthephysicalsystem,andanothersubmodelthatdescribesaspectsrelatedtoinformationflowinthecontrolsystem.Themultidimensionalarraybasedapproachofmodellingprovidesuswiththepossibilitytouseoneterminologyandthesameformalismformodellingbothsubsystems.Theconsequenceofusingthesameformalismisthatsimulationofthemechatronicssystemcanbeperformedusingonlyonesimulationenvironment

Keywords:

Mechatronics,System,Modelling

1.INTRODUCTION

Mechatronicssystemisdefinedasthesynergeticintegrationofmechanicalengineeringwithelectronics,andintelligentcomputercontrolinthedesignandmanufacturingofindustrialproductsandprocesses[5].Thecomponentsofmechatronicssystemsmustbedesignedconcurrently,thatis,theconstraintsimposedonthesystembyeachdisciplinemustbeconsideredattheveryearlystages.Therefore,propersystemdesignwilldependheavilyontheuseofmodellingandsimulationthroughoutthedesignandprototypingstages.Theintegrationwithinamechatronicssystemisperformedthroughthecombinationofthehardwarecomponentsresultinginaphysicalsystemandthroughtheintegrationoftheinformationprocessingsystemresultinginanintelligentcontrolsystem[7].

Themechatronicssystemthen,istheresultofapplyingcomputerbasedcontrolsystemstophysicalsystems.Thecontrolsystemisdesignedtoexecutecommandsinrealtimeinordertoselect,enhance,andsupervisethebehaviorofthephysicalsystem.Theonlypossiblewaytoguaranteethatthesecontrolfunctionswillkeepthebehaviorofthewholesystemwithincertainboundariesbeforeweactuallybuildit,istocreateamodeloftherealsystemthattakesintoaccountalltheimposedconstraintsbyboththehardwareandsoftwarecomponents.Thisimpliesthatamodeloftherealsystemmustbepowerfulenoughtocaptureallthepropertiesofmechatronicssystem.Thatincludes;

thedynamic,static,discreteevent,logic,aswellascostrelatedpropertiesoftherealsystem,ataskwebelieve,defiesanyfragmentedapproachofmodelling.Inthispaperwepresentaunifiedapproachformodellingmechatronicssystems.Thisunifiedapproachutilizesgeometricobjectsormultidimensionalarraystoformulatemodelsofmechatronicssystems.Themultidimensionalarraybasedapproachofmodellingprovidesuswiththepossibilitytousethesameformalismforalargevarietyofsystems[2,3,4,9].Theconsequenceofusingthesameformalismisthatsimulationofmechatronicssystemscanbeperformedusingonlyonesimulationenvironment.

2.MODELSTRUCTURE

Intuitivelyspeaking,amodelthatdescribesthedynamicbehaviorofagivensystemcannotbeusedtoinvestigatethestaticbehavioroftheverysamesystem.Therefore,inordertocaptureallaspects,weneedavarietyofmodels,eachoneofthemencapsulatessomeaspectsoftherealsystem.

Wewillconsiderthemechatronicssystemmodelasasetofconnectedsubmodels,eachsubmodelcorrespondstosomerealizableaspects.Inthisregard,thetermconnectedwasusedtoemphasizethedependencybetweenthevariablesinthesesubmodels.Throughouttheprocessofmodelling,weshalldistinguishbetweenthefollowingconcepts,seeFigure1.

Decomposition:

inordertohandlethecomplexityofmechatronicssystems,theyshouldbedecomposedintosubsystems.Thisdecompositioniscarriedoutonamultilevelfashionuntilwereachthebasicelementsthatconstitutethetotalsystem.Theprimitivesystemmodel:

isadescriptionofthesysteminthedisconnectedstate.Itexpressestherelationbetweenthevariablesintheindividualelementswhenthebondsbetweentheseelementsareremoved.Bythismodelweisolateaspecificbehavior;

static,dynamic,etc.,ineachelement.Apairoflocalvariablesdefinesthebehaviorofagivenelementlocally.TheConnectedsystemmodel:

isadescriptionofthesamesystemaftertakingtheinternalconstraintsintoaccount.Theinternalconstraintswithinthesystemaregivenbythewaythelocalvariablesareconnectedorrelateddirectlyaswellasindirectlybythevariablesoftheconnectedsystem.Theconnectedsystemmodelresemblestheactualstructureoftherealsystem.

Theappliedsourcesaregeneratedduetointeractionbetweenthesystemanditsenvironment.Theycouldbeseenastheexternalconstraintsimposedonthesystemoreveninherentconstraintsintheformofstoredenergyinsystemelements.

3.APPLICATIONEXAMPLE

Consider,themanufacturingsystemshowninFigure2.

Thesystemconsistsofaboringspindlepoweredbyadirectcurrentmotor.Thefeedforwardmotionoftheboringspindleiscarriedoutbymeansofahydrauliclinearactuator.Thehydraulicactuatorispoweredbyaconstantpressurehydraulicpump.Thevolumetricflowinthehydrauliccircuitiscontrolledbyaservovalve[8].

Theabovemanufacturingsystemhasthefollowingspecifications:

Thepositionsofboringspindlearesensedbythreemicrobreakers.Breaker（B）whichindicatesthattheboringspindleisattherearposition.Attherearpositiontherapidphasevalve（I）willbeswitchedoninordertoallowarapidforwardmotion（F）andthesignal（S）willswitchonthespindlemotor.Breaker（M）indicatesthattheboringspindlehasreachedthefeedingposition.Atthispositiontherapidphasevalvewillbeswitchedoffinordertostartacontrolledfeedforwardmotion.Thismotionisregulatedbytheservovalve（St）.Breaker（€）whichindicatesthattheboringspindlehasreacheditsfinalposition,atthispositionandthebackwardmotion（R）willbegin,simultaneouslytherapidphasevalve（I）willbeswitchedoninordertoallowarapidbackwardmotion.Itisalsospecifiedthattherotatingspeedofthespindlemotorshouldbekeptat3000rpm.duringboringtheworkpieceandthefeedforwardspeedmustbekeptat2cm/secunderallloadingconditions.Ourobjectiveistosetupacompletemodelofthegivensystemusingmultidimensionalarraysandtocarryoutnecessaryexperimentsonthemodeltoverifythatspecificationsaresatisfied.

3.1PhysicalSystemModelling

Whenmodellingphysicalsystems,weareconcernedwithmodellingtheevolutionofthephysicalvariablesthatliveswithinthissystem.ThedecompositionofthephysicalsystemisshowninFigure3.

Thegroupsofbasicphysicalelementsareclassifiedintothreecategories:

Generalizedresistor:

examplesofthiscategoryare;

electricresistor,mechanicaldamper,andhydraulicresistor.Generalizedcapacitor:

electriccapacitor,mechanicalspring,andhydraulicreservoir.Generalizedinductorexamplesofthiscategoryare;

electricinductor,mechanicalmass,andhydraulicinductor.Breakingdownthephysicalsystemintosubsystemsandfurtherintobasicelementswillprovideuswithasharpinsightabouttheevolutionofthephysicalquantitieswithineachsubsystem,yieldingtobetterunderstandingofthemodesandthestatesthateachsubsystemwouldattain.Theadvantagesofhavingsuchinsightwillbecomevisibleduringthedesignphaseofalocalcontrolsystem.

Modellingcanbeconsideredastheoppositeprocedureofdecomposition.Thedifferenceisthat,indecomposition,wedividethesystemintoindependentphysicalentities,whileinmodellingwereconnectthemodelsofthesephysicalentities.Therefore,modellingcanbeseenastheprocedureofconnection.

Inmodelling,westartatthebottomlevelofthishierarchyandmoveupwards.Ateachlevel,wepropagatefromaprimitivesystemmodeltoaconnectedsystemmodel.Inthesucceedinglevel,theprimitivesystemmodelwouldthenbeestablishedbyaggregatingtheconnectedsystemmodelsfromtheformerlevelasshowninFigure4.

Atthebottomlevelofeachsubsystem,theprimitivesystemmodelwillbeestablishedbyutilizingthegoverningequationorthefundamentallawofeachindividualelement.Thatfundamentallaw,suchasNewton'

slaworOhm'

slaw,describesthelocalbehaviorofthatelement.Directandindirectconnectionsthatresembletheinternalconstraintswithintheboundariesofeachsubsystemdefinethetransformationfromtheprimitivesystemmodeltotheconnectedsystemmodel.Forsystemswithlinearconnectionssuchasdirectcurrentservomotor,theinternalconstraintsaregivenbyoneconnectionobject,thevelocityobject（V）.Thevelocityobjectisa2-dimensionalarray,therowsinthatarraycorrespondtothevariablesintheprimitivesystem（localvariables）andthecolumnscorrespondtothevariablesintheconnectedsystem（globalvariables）.Thus,thevelocityobjectisatransformationfromtheglobalvariablesintheconnectedsystemmodeltolocalvariablesintheprimitivesystemmodel.

Themodelofthephysicalsystemissetupbyaggregatingdiagonallytheconnectedsystemmodelsofthehydraulicsubsystemandtheboringspindle.Modellingthephysicalsystemresultedinasetofdifferentallalgebraicequations[7].Inastatespaceform,thebehaviorofthephysicalsystemisgivenby:

y=~（A,x,u,~）Where（x）isthesetofinitialstatevariables,（u）isthesetofinputsources,（A）isthestatetransitionmatrixforthephysicalspecificcontrolfunctionoftruthorfalsehood（10）.