毕业设计论文 外文文献翻译 光信息科学与技术 光电目标位置和速度测量系统 中英文对照.docx

毕业设计论文 外文文献翻译 光信息科学与技术 光电目标位置和速度测量系统 中英文对照.docx

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毕业设计论文外文文献翻译光信息科学与技术光电目标位置和速度测量系统中英文对照

Electro-opticaltargetsystemforpositionandspeedmeasurement

Abstract

Thispaperintroducesanelectro-opticaltargetsystem（EOTS）coveringthespeedrangefromsubsonictosupersonic.Thismicrocomputer-basedsystemhasanovelstructureandshowsthecapabilityofpreciselydetectingthepositionaswellasthevelocityofsmallcaliberprojectilesinrealtime.AprototypeEOTSwhosetargetareais1m2hasbeenconstructedandtested.Aspeedaccuracyofbetterthan0.3%wasachieved.Apositionaccuracy,mainlydependentonthespacingbetweenphotodiodesinEOTS,ofbetterthan1mmonatargetareaof1m2wasalsoaccomplished.

Keywords:

Externalballistics,Nocontactmeasurement,Electro-opticaltechniques,Positionmeasurement,Speedmeasurement

1Introduction

Thespeedandpositionmeasurementsofprojectilesaretwoimportantitemsinballisticresearch.Todeterminetheseparameterspreciselyoneneedsanaccuratemeasuringsystem.Aconventionalmethod,namelythehangingup（andtakingdown）oftargetdiscs[l],thoughaccurateinpositionmeasuring,istimeconsuming.Ashot-positionindicator（SPI）,describedinReference2,canmeasurethepositionofahighspeedprojectilebyacousticmeasurement.However,theSPIdoesnotprovidethespeedinformation;neitherdoestheconventionalmethod.Besides,theSPIisusedwithinthelimitsofsupersonicprojectiles.

Tomeasurethespeedandpositionofprojectilesrapidlyandsimultaneously,differentelectro-opticalbasedsystemshavebeenproposed3-5].Thesesystemshavetheabilitytocoverthespeedrangefromsubsonictosupersonic.Onesystem,calledthetargetmeasurementsystem（TMS）[3],usesverticalandhorizontalbanksoflightsourcestoformtwoperpendicularlightgridsthatconstructthetargetarea.Anothersystem,calledtheelectro-opticalprojectileanalyzer[4],usesthesameprincipleasTMS,butsimplifieslightsourceswithfiberopticsbundlesandasinglelightsourceineachlightgrid.Theothersystem,calledtheelectronicyawscreen（EYS）[5],usesasolidstatelaserthatiscollimatedanddirectedtoaone-dimensionalbeamexpandersystemtoformafan-shapedlightscreen.Thislightscreenthenisreflectedbyamirrortoconstructaportionofthetargetarea.Thelightscreenismoreprecisethanthelightgridbecausethereisnodeadzoneinthetargetareaaswiththelightgridsystem.

Fromtheaspectofspeedandpositionmeasurement,wetakeadvantageoftheabovesystemsandproposeanovelsystem;theelectro-opticaltargetsystem（EOTS）[6].Weuseacylindricalmirrorthatreflectstheincidentlaserbeamintoa90ºfan-shapedlightscreen.Twosuchlightscreensconstructatwo-dimensionalpositioningsystem.Weevenproposeabentcylindricalmirrortogeneratea90ºlightscreenwithafewdegreesextendedinadirectionnormaltothelightscreentoreducethesensitivitytovibrations.

AprototypeEOTS,whosetargetareais1m2andmeasuredspeedrangeisfrom50m/sto1200m/s,hasbeenconstructedandtested.Aspeedrangeofupto5000m/scanalsobeexpectedaccordingtothesimulationresultsfromtheelectroniccircuitusingPSpice[7].Finally,anine-pointtestingresultfroma0.38in.pistolisshowninthispaper.Theresultshowsthatthestandarddeviationofpositionaccuracyislessthan1mm.

2BasicprincipleofEOTS

Fig.1showstheopticalconfigurationofEOTS.AlaserbeamfromaHe-Nelaserisdirectedontoacylindricalmirror.Thereflectedlaserbeamscreateafan-shapedlightscreenandaredirectedontophotodiodesthatareneatlyarrangedintoanL-shapedphotodiodearray.EOTSusestwolasersources,twocylindricalmirrorsandtwophotodiodearrays,whicharearrangedontheoppositesidesoftheEOTSbodytoformtwofan-shapedlightscreens.Eachlightscreeniscombinedwithitsownsignalprocessingcircuittoconstructanopticalgate.Althoughthereisadistancebetweenthetwoparallellightscreens,viewedfromadistancepoint,thesefanbeamsintersectinaregionofspacecalledthetargetarea（Fig.2）.Aprojectilecanbemeasuredonlyifittravelsthroughthistargetarea.

Fig.1OpticalconfigurationofEOTS

Fig.3showstheshotpositionoftheprojectileiscalculated.Thetargetarea,fortheconvenienceofillustration,isasquareofdimensionDoneachside.ThenumberofphotodiodesontheL-shapedphotodiodearrayis2N.Eachphotodiodeisnumberedinorder,asshowninthefigure.Forillustrationclarity,onlythephotodiodearrayandthecylindricalmirrorofthefirstopticalgateareshown.Theprojectileisconsideredtobeincidentnormallytothefirstandtothesecondopticalgateinsequence.Whentheprojectileblocksthelightscreens,therespectivephotodiodeswillbeactivatedbythedisturbance.Inthefirstopticalgate,thelaserbeamfromthecylindricalmirrortoeachphotod