毕业设计的论文中英翻译.docx

毕业设计的论文中英翻译.docx

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毕业设计的论文中英翻译

Anti-AircraftFireControlandtheDevelopmentofIntegratedSystemsatSperry

Thedawnoftheelectricalagebroughtnewtypesofcontrolsystems.Abletotransmitdatabetweendistributedcomponentsandeffectactionatadistance,thesesystemsemployedfeedbackdevicesaswellashumanbeingstoclosecontrolloopsateverylevel.Bythetimetheoriesoffeedbackandstabilitybegantobecomepracticalforengineersinthe1930satraditionofremoteandautomaticcontrolengineeringhaddevelopedthatbuiltdistributedcontrolsystemswithcentralizedinformationprocessors.Thesetwostrandsoftechnology,controltheoryandcontrolsystems,cametogethertoproducethelarge-scaleintegratedsystemstypicalofWorldWarIIandafter.

ElmerAmbroseSperry（I860-1930）andthecompanyhefounded,theSperryGyroscopeCompany,ledtheengineeringofcontrolsystemsbetween1910and1940.Sperryandhisengineersbuiltdistributeddatatransmissionsystemsthatlaidthefoundationsoftoday’scommandandcontrolsystems.Sperry’sfirecontrolsystemsincludedmorethangovernorsorstabilizers;theyconsistedofdistributedsensors,datatransmitters,centralprocessors,andoutputsthatdrovemachinery.ThisarticletellsthestoryofSperry’sinvolvementinanti-aircraftfirecontrolbetweentheworldwarsandshowshowanindustrialfirmconceivedofcontrolsystemsbeforethecommonuseofcontroltheory.Inthe1930sthetaskoffirecontrolbecameprogressivelymoreautomated,asSperryengineersgraduallyreplacedhumanoperatorswithautomaticdevices.Feedback,humaninterface,andsystemintegrationposedchallengingproblemsforfirecontrolengineersduringthisperiod.Bytheendofthedecadetheseproblemswouldbecomecriticalasthecountrystruggledtobuildupitstechnologytomeetthedemandsofanimpendingwar.

Anti-AircraftArtilleryFireControl

BeforeWorldWarI,developmentsinshipdesign,guns,andarmordrovetheneedforimprovedfirecontrolonNavyships.By1920,similarforceswereatworkintheair:

wartimeexperiencesandpostwardevelopmentsinaerialbombingcreatedtheneedforsophisticatedfirecontrolforanti-aircraftartillery.Shootinganairplaneoutoftheskyisessentiallyaproblemof“leading”thetarget.Asaircraftdevelopedrapidlyinthetwenties,theirincreasedspeedandaltituderapidlypushedthetaskofcomputingtheleadoutoftherangeofhumanreactionandcalculation.Firecontrolequipmentforanti-aircraftgunswasameansoftechnologicallyaidinghumanoperatorstoaccomplishataskbeyondtheirnaturalcapabilities.

Duringthefirstworldwar,anti-aircraftfirecontrolhadundergonesomepreliminarydevelopment.ElmerSperry,aschairmanoftheAviationCommitteeoftheNavalConsultingBoard,developedtwoinstrumentsforthisproblem:

agoniometer,arange-finder,andapretelemeter,afiredirectororcalculator.Neither,however,waswidelyusedinthefield.

WhenthewarendedinI918theArmyundertookvirtuallynonewdevelopmentinanti-aircraftfirecontrolforfivetosevenyears.Inthemid-1920showever,theArmybegantodevelopindividualcomponentsforanti-aircraftequipmentincludingstereoscopicheight-finders,searchlights,andsoundlocationequipment.TheSperryCompanywasinvolvedinthelattertwoefforts.AboutthistimeMaj.ThomasWilson,attheFrankfordArsenalinPhiladelphia,begandevelopingacentralcomputerforfirecontroldata,looselybasedonthesystemof“directorfiring”thathaddevelopedinnavalgunnery.Wilson’sdeviceresembledearlierfirecontrolcalculators,acceptingdataasinputfromsensingcomponents,performingcalculationstopredictthefuturelocationofthetarget,andproducingdirectioninformationtotheguns.

IntegrationandDataTransmission

Still,thecomponentsofananti-aircraftbatteryremainedindependent,tiedtogetheronlybytelephone.AsPrestonR.Bassett,chiefengineerandlaterpresidentoftheSperryCompany,recalled,“nosooner,however,didthecomponentsgettothepointoffunctioningsatisfactorilywithinthemselves,thantheproblemofproperlytransmittingtheinformationfromonetotheothercametobeofprimeimportance.”Tacticalandterrainconsiderationsoftenrequiredthatdifferentfirecontrolelementsbeseparatedbyuptoseveralhundredfeet.Observerstelephonedtheirdatatoanofficer,whomanuallyentereditintothecentralcomputer,readofftheresults,andtelephonedthemtotheguninstallations.Thiscommunicationsystemintroducedbothatimedelayandtheopportunityforerror.Thecomponentsneededtighterintegration,andsuchasystemrequiredautomaticdatacommunications.

Inthe1920stheSperryGyroscopeCompanyledthefieldindatacommunications.ItsexperiencecamefromElmerSperry’smostsuccessfulinvention,atrue-northseekinggyroforships.AsignificantfeatureoftheSperryGyrocompasswasitsabilitytotransmitheadingdatafromasinglecentralgyrotorepeaterslocatedatanumberoflocationsaroundtheship.Therepeaters,essentiallyfollow-upservos,connectedtoanotherfollow-up,whichtrackedthemotionofthegyrowithoutinterference.ThesedatatransmittershadattractedtheinterestoftheNavy,whichneededastableheadingreferenceandasystemofdatacommunicationforitsownfirecontrolproblems.In1916,SperrybuiltafirecontrolsystemfortheNavywhich,althoughitplacedminimalemphasisonautomaticcomputing,wasasophisticateddistributeddatasystem.By1920SperryhadinstalledthesesystemsonanumberofUS.battleships.

BecauseoftheSperryCompany’sexperiencewithfirecontrolintheNavy,aswellasElmerSperry’searlierworkwiththegoniometerandthepretelemeter,theArmyapproachedthecompanyforhelpwithdatatransmissionforanti-aircraftfirecontrol.ToElmerSperry,itlookedlikeaneasyproblem:

thecalculationsresembledthoseinanavalapplication,butthephysicalplatform,unlikeashipatsea,anchoredtotheground.SperryengineersvisitedWilsonattheFrankfordArsenalin1925,andElmerSperryfollowedupwithaletterexpressinghisinterestinworkingontheproblem.Hestressedhiscompany’sexperiencewithnavalproblems,aswellasitsrecentdevelopmentsinbombsights,“workfromtheotherendoftheproposition.”Bombsightshadtoincorporatenumerousparametersofwind,groundspeed,airspeed,andballistics,soananti-aircraftgundirectorwasinsomewaysareciprocalbombsight.Infact,partofthereasonanti-aircraftfirecontrolequipmentworkedatallwasthatitassumedattackingbombershadtoflystraightandleveltolineuptheirbombsights.ElmerSperry’sinterestswerewarmlyreceived,andinI925and1926theSperryCompanybuilttwodatatransmissionsystemsfortheArmy’sgundirectors.

TheoriginaldirectorbuiltatFrankfordwasdesignatedT-1,orthe“WilsonDirector.”TheArmyhadpurchasedaVickersdirectormanufacturedinEngland,butencouragedWilsontodesignonethatcouldbemanufacturedinthiscountrySperry’stwodatatransmissionprojectsweretoaddautomaticcommunicationsbetweentheelementsofboththeWilsonandtheVickerssystems（VickerswouldeventuallyincorporatetheSperrysystemintoitsproduct）.Wilsondiedin1927,andtheSperryCompanytookovertheentiredirectordevelopmentfromtheFrankfordArsenalwithacontracttobuildanddeliveradirectorincorporatingthebestfeaturesofboththeWilsonandVickerssystems.From1927to193.5,Sperryundertookasmallbutintensivedevelopmentprograminanti-aircraftsystems.Thecompanyfinanceditsengineeringinternally,sellingdirectorsinsmallquantitiestotheArmy,mostlyforevaluation,foronlytheactualcostofproduction[S].Ofthenearly10modelsSperrydevelopedduringthisperiod,itneversoldmorethan12ofanymodel;theaverageorderwasfive.TheSperryCompanyoffsetsomedevelopmentcostsbysalestoforeigngovemments,especiallyRussia,withtheArmy’sapproval191.

TheT-6Director

Sperry’smodifiedversionofWilson’sdirectorwasdesignatedT-4indevelopment.Thismodelincorporatedcorrectionsforairdensity,super-elevation,andwind.AssembledandtestedatFrankfordinthefallof1928,ithadproblemswithbacklashandreliabilityinitspredictingmechanisms.Still,theArmyfoundtheT-4promisingandaftertestingreturnedittoSperryformodification.Thecompanychangedthedesignforsimplermanufacture,eliminatedtwooperators,andimprovedreliability.In1930SperryreturnedwiththeT-6,whichtestedsuccessfully.Bytheendof1931,theArmyhadordered12oftheunits.TheT-6wasstandardizedbytheArmyastheM-2director.

SincetheT-6wasthefirstanti-aircraftdirectortobeputintoproduction,aswellasthefirstonetheArmyformallyprocured,itisinstructivetoexamineitsoperationindetail.Atechnicalmemorandumdated1930explainedthetheorybehindtheT-6calculationsandhowtheequationsweresolvedbythesystem.Althoughthispublicationlistsnoauthor,itprobablywaswrittenbyEarlW.Chafee,Sperry’sdirectoroffirecontrolengineering.Thedirectorwasacomplexmechanicalanalogcomputerthatconnectedfourthree-inchanti-aircraftgunsandanaltitudefinderintoanintegratedsystem（seeFig.1）.JustaswithSperry’snavalfirecontrolsystem,theprimarymeansofconnectionwere“datatransmitters,”similartothosethatconnectedgyrocompassestorepeatersaboardship.

Thedirectortakesthreeprimaryinputs.Targetaltitudecomesfromastereoscopicrangefinder.Thisdevicehastwotelescopesseparatedbyabaselineof12feet;asingleoperatoradjuststheanglebetweenthemtobringthetwoimagesintocoincidence.Slantrange,ortherawtargetdistance,isthencorrectedtoderiveitsaltitudecomponent.Tw