机电一体化英文

1、Mechatronics机电一体化1 Ablendofmechanicsandelectronics,mechatronicshascometomeanthesynergisticuseofprecisionengineering,controltheory,computerscience,andsensorandactuatortechnologytodesignimprovedproductsandprocesses.2 Thestandardclothesdryeristypicallycontrolledbyamechanicaltimer.Theuseradjuststhetimer

2、accordingtothesizeanddampnessoftheload.Ifthetimingdeviceisnotsetproperly,thedryingcyclemaybetooshortandthelaundrymaycomeoutwet,orthemachinecouldrunlongandwasteenergy.3 Aclothesdryer,however,mightbefittedwithasensor-basedfeedbacksystemthatletsthemachinemeasurethemoisturecontentofthefabricsortheexhaus

3、tair,andturnitselfoffwhentheloadisdry.Operatingperformanceisenhancedandenergyuseisloweredasaresult.Theredesigneddryermightevenbecheapertobuy,dependingmainlyonthecostofthecomponentsthatcomprisetheelectromechanicalcontrolsystem.4 Thecomputerdiskdrive,suchasCheetahfromSeagateTechnology,isoneofthebestex

4、amplesofmechatronicdesignbecauseitexhibitsquickresponse,precision,androbustness.5 ManyU.S.-traineddesignengineerswouldsaythattheimproveddryeristheresultofup-to-datebutconventionaldesignpractices.Areliableyetrelativelyinaccuratemechanicaldevicewasreplacedbya"smarter"electroniccontrol.Inmuch

5、oftherestoftheworld,however,designengineerswouldsaythatthedryerredesignfollowedtheprinciplesofmechatronics.6 Mechatronicsisnothingnew;itissimplytheapplicationofthelatesttechniquesinprecisionmechanicalengineering,controlstheory,computerscience,andelectronicstothedesignprocesstocreatemorefunctionaland

6、adaptableproducts.This,ofcourse,issomethingmanyforward-thinkingdesignersandengineershavebeendoingforyears.7 ThevaguelyawkwardwordwasfirstcoinedinJapansome30yearsago.Sincethen,mechatronicshascometodenoteasynergisticblendofmechanicsandelectronics.Theword'smeaningissomewhatbroaderthanthetraditional

7、termelectromechanics,whichtomanyconnotestheuseofelectrostaticorelectromagneticdevices.Itisalsoanamorphous,heterogeneous,andcontinuallyevolvingconceptwith1,001definitions,manyofwhicharesobroadorsonarrowtobeofseeminglymarginaluse.8 Mechatronicsismorethansemantics,however.It'sasignificantdesigntren

8、dthathasamarkedinfluenceontheproduct-developmentprocess,internationalcompetitioninmanufacturedgoods,thenatureofmechanicalengineeringeducationincomingyears,andquiteprobablythesuccessmechanicalengineerswillhaveinbecomingteamleadersorengineeringmanagers.DefiningMechatronics9 ForTakashiYamaguchi,whowork

9、satHitachiLtd.'sMechanicalEngineeringLaboratoryinIbaraki,Japan,mechatronicsis"amethodologyfordesigningproductsthatexhibitfast,preciseper网formance.Thesecharacteristicscanbeachievedbyconsideringnotonlythemechanicaldesignbutalsotheuseofservocontrols,sensors,andelectronics."Headdedthatitis

10、alsoveryimportanttomakethedesignrobust.Computerdiskdrives,forexample,areaprimeexampleofthesuccessfulapplicationofmechatronics:"Diskdrivesarerequiredtoprovideveryfastaccess,precisepositioning,aswellasrobustnessagainstvariousdisturbances,"hesaid.10 ForGiorgioRizzoni,associateprofessorofmecha

11、nicalengineeringatOhioStateUniversityinColumbus,mechatronicsis"theconfluenceoftraditionaldesignmethodswithsensorsandinstrumentationtechnology,driveandactuatortechnology,embeddedreal-timemicroprocessorsystems,andreal-timesoftware."Mechatronic(electromechanical)products,hesaid,exhibitcertain

12、distinguishingfeatures,includingthereplacementofmanymechanicalfunctionswithelectronicones,whichresultsinmuchgreaterflexibilityandeasyredesignorreprogramming;theabilitytoimplementdistributedcontrolincomplexsystems;andtheabilitytoconductautomateddatacollectionandreporting.Thediagramatleftillustratesth

13、atmechatronicsiswheremechanics,electronics,computers,andcontrolsintersect11 "Mechatronicsisreallynothingbutgooddesignpractice,"saidMasayoshiTomizuka,professorofmechanicalengineeringattheUniversityofCalifornia,Berkeley."Thebasicideaistoapplynewcontrolstoextractnewlevelsofperformancefro

14、mamechanicaldevice."Itmeansusingmodern,cost-effectivetechnologytoimproveproductandprocessperformanceandflexibility.Inmanycases,theapplicationofcomputerandcontrolstechnologyyieldsadesignsolutionthatismoreelegantthanthepurelymechanicalapproach.Byhavingagoodideaofwhatcanbedoneusingotherthanmechani

15、calmeans,designfreedomincreasesandresultsimprove,accordingtoTomizuka,whoisalsoeditor-in-chiefofthequarterlyIEEE/ASMETransactionsonMechatronicsjointlypublishedbytheInstituteforElectricalandElectronicsEngineersandASME.12 Thejournal,firstpublishedinMarch1996,isanotherindicationthattheimportanceofthisin

16、terdisciplinaryareaisbeingrecognized.Transactionscoversarangeofrelatedtechnicalareas,includingmodelinganddesign,systemintegration,actuatorsandsensors,intelligentcontrol,robotics,manufacturing,motioncontrol,vibrationandnoisecontrol,microdevicesandoptoelectronicsystems,andautomotivesystems.TheRootsofM

17、echatronics13 MechatronicswasfirstusedintermsofthecomputercontrolofelectricmotorsbyanengineeratJapan'sYaskawaElectricChelate1960s.ThewordhasremainedpopularinJapan,andhasbeeningeneraluseinEuropeformanyyears.Althoughmechatronicshasbeenslowtogainindustrialandacademicacceptanceasafieldofstudyan

18、dpracticeinGreatBritainandtheUnitedStates,itsincreasinglyprominentplaceworldwideisshownbythegrowingnumberofundergraduateandpostgraduatemechatronicscoursesnowbeingoffered.14 Manyengineerswouldcontendthatmechatronicsgrewoutofrobotics.Earlyroboticarms,thenunabletocoordinatetheirmovementsandwithoutsenso

19、ryfeedback,benefitedgreatlyfromadvancesinkinematics,dynamics,controls,sensortechnology,andhigh-levelprogramming.Thesamebatteryofmoderntechnologiesthatmaderobotsmoreflexibleandthusmoreusefulwasthenbroughttobearonthedesignofnewgenerationsofhigh-performance,adaptablemachineryofallkinds.15 Inthe1970s,me

20、chatronicswasconcernedmostlywithservotechnologyusedinproductssuchasautomaticdooropeners,vendingmachines,andautofocuscameras.Simpleinimplementation,theapproachencompassedtheearlyuseofadvancedcontrolmethods,accordingtoTransactionseditors.16 Inthe1980s,asinformationtechnologywasintroduced,engineersbega

21、ntoembedmicroprocessorsinmechanicalsystemstoimprovetheirperformance.Numericallycontrolledmachinesandrobotsbecamemorecompact,whileautomotiveapplicationssuchaselectronicenginecontrolsandantilock-brakingsystemsbecamewidespread.17 Bythe1990s,communicationstechnologywasaddedtothemix,yieldingproductsthatc

22、ouldbeconnectedinlargenetworks.Thisdevelopmentmadefunctionssuchastheremoteoperationofroboticmanipulatorarmspossible.Atthesametime,new,smaller-evenmicroscale-sensorandactuatortechnologiesarebeingusedincreasinglyinnewproducts.Microelectromechanicalsystems,suchasthetinysiliconaccelerometersthattriggera

23、utomotiveairbags,areexamplesofthelatteruse.18 Assignificantasthesedevelopmentsmayseem,agooddealofskepticismremainsabouttheideaofcodifyingtheminanengineeringfieldcalledmechatronics."It'scertainlyacatchyword,"saidcontrolsexpertErnestO.Doebelin,professoremeritusatOhioStateandanASMEFellow,

24、"butit'sanevolutionary,ratherthanrevolutionary,development.Nowthatcomputersaresmallandrelativelycheap,itjustmakessensefordesignerstobuildthemintoproducts.Mechatronicsisreallythefamiliaritywithalltheothertechnologies-computers,software,advancedcontrols,sensors,actuators,andsoforth-thatmaketh

25、eadvancedproductspossible."19 SimilarsentimentswereexpressedbyDavorHrovat,seniorstafftechnicalspecialistattheFordResearchLaboratoryinDearborn,Mich.:"Thewordsinglesoutanareathatperhapsisnotasinglearea.Mechatronicsismixtureoftechnologiesandtechniquesthattogetherhelpindesigningbetterproducts.

26、"20 Howevermechatronicsisdefined,itmeans"wenowhaveviabletechnologyforcomputercontrolofmechanicalsystemsatalllevels,fromtoasterstoautos,"saidDavidM.Auslander,professorofmechanicalengineeringatBerkeley."Todaywehavemechanicalsystemsforwhichperformanceisdefinedbywhat'sinacomputer

27、,whetherit'ssoftwarealgorithms,neuralnetworks,orfuzzylogic.Thatalonemakesitdifferentfromanythingyoucoulddo25yearsago."21 Auslandertakesaverygeneralizedviewofthetopic."Anysysteminwhichyoucontrolormodulatepowerisacandidateforcomputercontrol.Foranymechanicalcomponentyoucanaskthequestion:W

28、hatisitspurpose?Doesittransmitpower?Orisitspurposecontrolandcoordination?Computers,software,andelectronicscangenerallydothissecondfunctionmoreefficiently-simpler,cheaper,withmuchmoreflexibility."Thisapproach,heemphasized,constitutesatotallydifferentviewofhowmechanicalsystemsworkcomparedwithprev

29、iousconceptions."Thisisamachineviewedfromthecontrolsoutward.22 Followingmechatronicprinciples,GeneralElectric'sProfileSuper32clotheswasherfeaturesasensor-basedfeedbackcontrolthatmaintainscorrectwatertemperaturenomattertheloadsize23 Considerthestandardmulticolorprintingpressthismagazineusedt

30、obeprintedon,"Auslanderadded."Untilrecently,webpresseshadline-shaftcontrolsinwhichalongshaftcoordinatesoperationsfromstationtostation.Nowit'sdoneallbycomputercontrol,whichmakesitmucheasiertochangethemachineovertoanewsetup."24 TheviewofBelgianroboticsresearcherHendrikM.J.VanBrussel

31、,publishedinTransactions(June1996),followsasimilarfundamentalthemebutwithadifferentemphasis."Inthepast,machineandproductdesignhas,almostexclusively,beenthepreoccupationofmechanicalengineers,"hewrote.Solutionstocontrolandprogrammingproblemswereaddedbycontrolandsoftwareengineers,afterthemach

32、inehadbeendesignedbymechanicalengineers.25 Thissequential-engineeringapproachusuallyresultedinsuboptimaldesigns."Recently,machinedesignhasbeenprofoundlyinfluencedbytheevolutionofmicroelectronics,controlengineering,andcomputerscience,"VanBrusselwrote."Whatisneeded,asasolidbasisfordesig

33、ninghigh-performancemachines,isasynergisticcross-fertilizationbetweenthedifferentengineeringdisciplines.Thisisexactlywhatmechatronicsisaimingat;itisaconcurrent-engineeringviewofmachinedesign."Hethenofferedhisworkingdefinitionoftheterm:"Mechatronicsencompassestheknowledgebaseandthetechnolog

34、iesrequiredfortheflexiblegenerationofcontrolledmotion."26 Anessentialfeatureinthebehaviorofamachine,VanBrusselcontinued,istheoccurrenceofcontrolledand/orcoordinatedmotionofoneormoremachineelements."Thegenerationandcoordinationoftherequiredmotions,suchthattheincreasinglygrowingperformancean

35、daccuracyrequirementsaresatisfied,istheraisond'etreofmechatronics."27 VanBrusselpointedoutthattraditionalmechanismsarelimitedintheirflexibilityingeneratingawidevarietyofmotions.Alsorestrictedistheirpotentialforcreatingcomplexfunctionalrelationshipsbetweenthemotionoftheactuatorandthatofthedr

36、ivenelement.Yetanotherlimitationofpurelymechanicaldrivesystemsistheirinherentlackofaccuracy,causedbyfriction,backlash,wind-uperrors,resonances,dimensionalerrors,andsoforth.I28 "Theserestrictionscanbealleviatedbyeliminatingorsimplifyingthe'forced-motion'mechanismbetweenactuatoranddrivene

37、lements,"hewrote.Instead,eachdrivenelementisprovidedwithadrivemotorandapositionsensor.Amotioncontrollergeneratestherequiredrelationshipsbetweenthemotionsofthedifferentdrivenelements."Themotionsynchronizationfunctionisshiftedfromtheerror-pronehardwaremechanismtotheflexiblesoftwarecontroller

38、.Byapplyingthemechatronicsapproach,alargenumberofmotionscanbesynchronized,evenatlongdistancesawayfromeachother."29 Underexternalforces,arangeofsecondaryeffectssuchasvibrationandnoisecanadverselyaffectthefunctionalbehaviorofmachineelementsandinstruments,accordingtoVanBrussel.Passivedampingtreatm

39、entsareavailable,buttheyhavelimitedapplicability."Themechatronicapproachcanprovidemoreeffectivesolutions.Basedonthestateinformationaboutvibrationandnoiselevels,capturedbyappropriatesensors,thevibrationsarecounteractedbyactuatorsdistributedoverthestructure.Themachineelementsbecomeactive(smartstr

40、uctures)."Thetermadaptivestructurescanbeused"whenthebehaviorofthestructurecanbechangedatwill,withoutmechanicalmodifications."InstitutionalImplications30 Beyonddesigntheory,Auslandersaid,"mechatronicsisalsosayingsomethingaboutindustrialstructure."Inthenewparadigm,"thefoc

41、alpointisnottraditionalmachinedesign,whichiswhatindustryandthereforeuniversitiesarepresentlygearedtoteach.Inthefuture,thefocalpointwillbethemechatronicsspecialist."31 "It'salwaysabitembarrassingtotalkaboutmechatronics,"saidKevinCraig,associateprofessorofmechanicalengineeringatRens

42、selaerPolytechnicInstituteinTroy,N.Y."Asfarasengineeringpracticegoes,therereallyisn'tanythingnewhere,exceptevolutionaryadvancesincomputers,sensors,actuators,andtherest.Whatisnewfromtheeducationalviewpointisthatwe'reteachingmechanicalengineershowtouseelectronics,howtoprogramcomputerstodo

43、real-timecontrol,howtodocontroldesign,andthentointegrateallthisintothedesignprocess.32 "It'saninterdisciplinaryapproach,"headded."Dotheintegrationrightfromthebeginning;don'tjustaddacontrolsystemattheend.Controlsusedtobelefttospecialists-mostlyelectricalengineers.That'snott

44、rueanymore."Besidesteachingathree-dayshortcourseonmechatronicsaspartofanASMEProfessionalDevelopmentprogram,Craighasalsoworkedontwovideotapeseriesonthetopic.33 "knowledMechatronicsdoesnotchangethedesignprocess,"Craigsaid."Itgivestheengineergreaterge,sotheconceptsthataredevelopedar

45、ebetter,andcommunicationswithotherengineeringdisciplinesisimproved.Theresultisahighlybalanceddesign.34"Onethingthatisnotatallnotclearishowallthisadditionalmaterialshouldbedeliveredtothestudent,"observedEdCarryer,consultingassociateprofessoratStanfordUniversityinPaloAlto,Calif."Mostmec

46、hanicalengineeringcurriculaarealreadystuffedtothegunnels,"hesaid."It'seitheroverloadtheundergradsormakeitthefocusofacertificateprogramatthemaster'slevel."35 Fewacademicsexpectmechatronicstoattainthelevelofaformallyacceptedengineeringdiscipline."Ouracademicsystemtendstores

47、isttheformingofnewdisciplines,"Auslandersaid."Forexample,controlshasbeenawell-recognizedandimportantdisciplinesincetheSecondWorldWar.However,therearefewcontroldepartmentsintheUnitedStates.It'smostlytaughtinmechanicalengineering,electricalengineering,andsomechemicalengineeringdepartment

48、s.Yetwegraduatelotsofpeoplewhodothecontrolsfunction."Heconcludedthatmechatronics'placeintheacademichierarchyisreallyanorganizationalandbureaucraticissue.36 Intheshortcoursesheteaches,"besidesstudentsyougettheoccasionalprofessorwhowantstolearnwhattheuniversitiesaredoinginmechatronics,so

49、theycansetuptheirownprograms.Therestarepracticingmechanicalengineerswhobasicallywanttoknow'What'sthismechatronicsstuffwekeephearingabout?'37 ThepracticingengineersCraigmeetsstilltendtorelyonresultsofexperiments-buildandtestmethods.Surprisingly,"theydon'tdomuchmodelingoranalysis.

50、We'resayingthattheywon'tbeabledothatmuchlonger,becauseyoucan'tgetproductstomarketquicklyenoughintoday'smarkets.Youneedtomodelandpredict,buildaprototype,thenvalidateyourpredictions."38 Ford'sHrovatalsostressedtheneedformechanicalengineerstolearnadvancedmodelingandsimulationme

51、thods.Hecitedparticularlytheuseofbondgraphs-transfer-functionblockdiagramsthatdenotepowerflowsandinformationflows-todepict"meansshifting,"theprocessoffindingalternativemeanstoaccomplishadesigngoal.Forexample,ifthereisnosuitableelectricalmeansofprovidingsomedesiredactuation,thedesignercouldgotoapneumaticorhydraulicsystem-themeanstoanendareshiftedtoasubstitutetechnology."FromwhatIsee,theuseofbondgraphsisdefinitelythetrend,"Hovratsaid.CareerPathsinMechatronics39 "Mechanicalengineersareoftenatalo