畢業設計說明書英文文獻及中文翻譯學生姓名：學號：學院：信息與通信工程學院專業：通信工程指導教師：**大學英文文獻原文及翻譯第17頁共17頁NovelOpticalSensorforPreciseTiltAngleMeasurementABSTRACTAnovelopticalsensor,whichcanmeasureinclinationangleortiltangleoftwoaxessimultaneouslyandprecisely,isintroduced.Thissensorisbasedontheprincipleoflaserinterferencesoithasveryhighaccuracy.Aprototypesensorisdesigned,builtandevaluatedtodemonstratethenovelconcept.Itisanoptoelectronicsensor.Therearenomovingpartsinthesensor.Afluidhorizontalthatisabsolutelyperpendiculartothetrueverticalprovidesthereferenceplane.Theanglebetweenthesensorandtheabsolutehorizonchangeswiththeinclinationoftheobjectbeingmeasured.Thesechangesarereflectedinthewayoffringepattern’scentrepositionshift.Differentinterferencepatternscentrelocationsaregeneratedwhentiltanglevaried.Theinterferencefringepatternarerecordedandprocessedtotranslateintothetiltanglesoftwoaxes,horizontalandvertical.Theaccuracycanreachashighas+/-1arcsecondwiththemeasurementrangeof700arcsecondswhen1024by1024pixelsimagesensorisutilized.Keywords:tiltanglesensor,inclinometers,laserinterferenceI.INTRODUCTIONThereareseveralkindsofcommercialsensorfortiltanglemeasurement,whichareavailableinthemarket.Someknownastiltanglesensor,someareknownasinclinometers.Theybaseondifferentworkingprinciples.Electrolyticliquid[1],capacitance[2]andpendulum[3]arethethreemainworkingprinciplesthatmosttiltanglesensororinclinometerusuallybaseon.Hereweproposeanovelopticalmethodandbuildupanoptoelectronicsensorwithlaser,opticalcomponentsandimagesensor.Itcandoprecisetiltanglemeasurementsimultaneously.Thereisnomechanicalmovementpart.Theworkingprincipleisbasedonopticalinterferometry.Coherentlaserisusedasthelightingsource.Itwillgothroughaliquidoilbox,whichisbuiltbyaglasscontainerfilledwithliquidoil.Afluidhorizontalthatisabsolutelyperpendiculartothetrueverticalprovidesthereferenceplane.Whenlaserbeampassthroughtheoilboxtwobeamsarereflectedbackbysurfaceoftheliquidandcontainerglass.Interferencefringesareformedwiththesetwobeams.Thefringepatternswillshiftincorrespondingtothechangesofthetiltangles.Thefringepatternsiscapturedandprocessedtogivethetiltangleinformation.Opticalworkingprinciplemakesitinsensitivetomagneticfield.Thesensorcanmeasuretwoaxesinclinationanglesimultaneously.Afluidhorizontalmakesurethereferenceplaneisanabsolutehorizontalplane.Highsensitiveopticalinterferencemeasurementprincipleassuresthehighaccuracy.Aprototypeofthemethodhasbeenbuiltupandevaluated.Experimentalresultsshowthetiltanglechangesrelativetosealevelcanbedetectedattheaccuracyof+-1arcsecondwithinthemeasurementrangeof700arcseconds.II.PRINCIPLEFigure1illustratestheschematicdiagramofworkingprinciple.PointOisthefocalpointofbeamexpandinglens.PointOcanbeconsideredasapointlightsource.Itemitssphericalwave-front.Liquidoilsurfacewillalwaysmaintainhorizontallyduetothegravityforceoftheearth.Theoilsurfaceisusedasthereferenceplane.Thecontainerismadeofglass.Itsbottomsurfacewillinclinetogetherwiththetargetobjectwhenthesensorisplacedonthetarget.Thelightfromoilsurfaceandglasssurfacewillinterferencetoformcircularfringespattern(seeFig.4).Theinclineanglecanbemeasuredwiththecentrepositionchangesofcircularfringes.PisthemirrorimageofOagainsttoglass-airsurfaceandQisthemirrorimageofOagainsttooil-airsurface.Theoil-airsurfacerepresentsthehorizontalplane.WhentheglasssurfacepositionedparallelwithoilsurfacethePandQareinthesamelineperpendicularwithoilsurface.Thislineisalsotheopticalaxisoftheopticalsystem.Thefringesarecircularfringeswithcommoncenter.Whentheoilboxisinclinedtheglasssurfacehasatiltangleaagainsttotheoilsurface.（1）wherenistherefractionindexofglass.Whenthetiltangleistiny,theaboveequationcanbesimplifiedas（2）Wecanobtainthefollowingequationfromand（3）whereristhecenterpositionofcircularfringes.Disthedistanceofthereceivingscreentotheglasssurfaceofoilbox.histhethicknessofglassandoil.nistherefractionindexofglassandoil(hereweassumetheglassandoilhavesameindexsincetheyareveryclose).AssumethatsothathisnegligiblerelativetoD.(4)Fromequation(4)n,Dandharefixedoncethesetupisassembled.Let,calledsystemconstant.Thissystemparametercanbeobtainedthroughcalibrationprocess.Henceequation(4)canbewrittenas（5）wherercanbecalculatedwithimageprocessingtechniqueandhencedothetiltangle.Fig.1SchematicdiagramofmeasurementprincipleIII.DESCRIPTIONOFSENSORFigure2showsthedetaillayoutoftheopticalheadofthesensor.Itincludeslaser1,beamexpander2,beamsplitter3,mirror4andliquidoilbox5.Apointlightsourceemitssphericalwave-front.Thisbeamgoesthroughtheoilbox.Itisreflectedbytheglasssurfaceandoilsurfacerespectively.Thesetwowave-frontsmeettogetheragainaftertheypassdifferentopticalpaths.Ifthecoherentlengthofthepointlightsourceislongerthantheopticalpathdifference,thesetwobeamswillinterfereandformcircularfringes.Whenonesurfacetiltsthecenterofthecircularfringeswillshiftaccordingly.Whentheopticalpathchanges,thefringeswillbegeneratedorabsorbedaccordingly.Onefringechangeoccursincorrespondingtoopticalpathdifference,whereisthewavelengthofthelightsource.Fig.2LayoutofopticalsensorheadAsillustratedinFigure2,thelaser1emitsalaserbeam.Thislaserbeamisexpandedbyabeamexpander2toformasphericalwave-frontbeam.Subsequentlythisbeamgoesthroughtheliquidoilbox5perpendicularly.Thereflectionsoccurinthesurfacesformedbymediaslayerswithdifferentrefractionindexes.Thereflectionratioisdeterminedbytheformulawhenincidentdirectionisperpendicularlytothereflectionplan（6）Whereandrepresentthediffractionindexofthetwomedias.Thecloserthetworeflectionindexesthelesslightreflected.Whenequalstothereisnoreflectionoccurringatthissurface.Whilebuildingthesensoroneofthemostimportantrequirementsistomakesurethatthecentersofallopticalcomponentsarepositionedonthesameline,e.g.theopticalaxis.Duetomechanicaltoleranceandthepreciserequirementsofthesensorhead,afinetuneonthealignmentoftheopticalheadisnecessarytomakesurethesensorcanworkwell.Themethodbeginswithaligningthelasertoenablethelaserbeamparalleltothebaseplatethatalltheopticalcomponentswillbemountedon.Subsequentlyinstallthebeamsplitter.Thedirectionoflaserbeamwillbechangebyarightangleandincidenttotheliquidoilbox.Adjustthebeamsplitteruntilthelaserbeamincidenttotheliquidoilboxperpendicular.Installbeamexpandertoconverttheparallelbeamintoasphericallaserbeam.Alignthebeamexpanderaxiswiththesystemopticalaxis.Thereflectedwavefrontscomingfromglasssurfaceandoilsurfacewillgothroughbeamsplitterandchangeitsdirectionatrightanglebymirrortoentercamera.Thealignmentofcameramakesensurethelaserbeamtobeimagedatthecenteroftheimagingplane.Thatis,theimagingaxisisnormaltotheimagingplane.Furthermore,themethodneedstofurtheraligntheliquidoilboxwiththethreescrews10mountedintheoilboxtoensuretiltanglewithinthemeasurementrange.Apatternwithcircularfringeswillappear.Adjustthescrew10untilthecenterofthefringepatternpositionedinthecenterofimagesensorasillustratedinFigure4A.Fig.3SchematicdiagramofoilboxFigure3showsthedetailsofliquidoilbox.Thefirstsurfaceisformedbyair-glass,calledair-glasssurface;thereflectionratioisabout3%sincetherefractionindexofairis1andtheglassweusedisaround1.4.Thesecondsurfaceisformedbyglass-oil,calledglass-oilsurface.Thereisalmostnoreflectioninthissurfacesincewechooseproperoilwiththecloserefractionindexwiththeglass.Thethirdsurfaceisconstructedbytheoilandair.Sothereflectionratioisaboutthesameasthefirstsurface.Thetworeflectedwavefrontsbythefirstglass-airsurfaceandthethirdoil-airsurfacewillmeettogetherandinterferenceeachothertoformapatternwithcircularinterferencefringesasillustratedinFigure4.Whentheglasssurfaceisparallelwithoilsurfacethecenterwillbepositionedintheopticalaxis(Fig.4A).Thepositionofcenterofthecircularfringeswillshiftwhenthetiltanglevaries(Fig.4B).Fig.4AInterferencefringepatterns(centerposition,nontilted)Fig.4BInterferencefringepatterns(sideposition,tiltedangle)IV.CALIBRATIONItisvitalforcalibrationofthesensortoensureanaccurateandreliablemeasurement.Apropercalibrationmakessurethatthecenterofthecircularfringesispositionedinthecenterportionoftheimagesensorwhenthesensorisplacedhorizontally.Thepurposesofthecalibrationarenotonlyobtainingsystemconstanthofequation(6)butalsocorrectingerrorscausedbyopticalaberration.Theconceptofcalibrationistoputoursensorandthebenchmarksensorontothesameplatethenchangethetiltanglesoftheplatetorecordthereadingsofoursensorandthebenchmarksensors.Figure5showsschematicdiagramofourcalibrationworkstationforthecalibrationofthesensor.Theworkstationconsistsofaflatplatesupportedatthreepointsandtwohighaccuratesingleaxistiltanglesensorswithaccuracyashighas1arcsecond.Thetwosensorsarepositionedatarightangle,oneisalongwithx-axistomonitorthechangeinxdirectionandtheotherisalongwithy-axistomonitorthechangeinydirection.Fig.5SchematicdiagramofcalibrationplatformTheplateissupportedatthreepointswiththreescrews.Itiseasytochangethetiltangleoftheplatebyadjustingthethreescrews.Ouropticalsensorheadisplacedinthecenteroftheplateandalignedwithxandyaxisofthestation.First,adjustthebaseplateuntilthereadingsofthesensorequalto0tolettheworkstationplateisparalleltothesealevel.Second,mountouropticalsensorthatneedstobecalibratedontotheplate.Alignthexandyaxiswiththebenchmarksenor.Third,adjustthelevelofliquidoilboxwiththethreescrewsonthecoveroftheliquidoilboxuntilthecentercircularfringesmovetothecenteroftheimagesensor.Thisadjustcanmakesurethepropermeasurementrange.Forth,changedifferenttiltanglesbymeansofadjustingthedifferentheightsofscrew.Recordthereadingsofthebenchmarksensorandcalculatethetiltanglesoftwoaxeswithoursensor.Thereadingsshouldcoverthewholemeasurementrange.Calibrationcoefficientcanbeobtainedwiththiscalibrationdata.Afterinputthecalibrationcoefficientintosoftwareapplicationprogram,thecalibrationprocessisover.Fig.6AshowsthecalibrationlineinXaxis.Fig.6BshowsthecalibrationlineinYaxis.Fig.6AMeasurementresultsofXaxisFig.6BMeasurementresultsofYaxisV.CONLUSIONAnovelopticalsensorwasinvented.Aprototypehasbeenbuiltupandevaluated.Accuracyof+-1arcsecondwithinthemeasurementrangeof700arcsecondshasbeenachieved.Itcanmeasureinclinationangleortiltangleoftwoaxessimultaneouslyandprecisely.Thissensorisbasedontheprincipleoflaserinterference.Ithasthefollowingmainadvantagescomparewithotherinclinometers.(1)Highaccurate.Itisopticalinterferenceprinciplebasedsensor.Anyvariationlessthan,e.g.0.3microninopticalpathwillcausethemovementofinterferencefringepattern.Thistinychangeisdetectedandconvertedtotiltangle.(2)Insensitivetomagneticenvironment.(3)Optoelectronicsensor,nomechanicalmovingparts.(4)Twoaxesanglesmeasurementatthesametime.REFERENCES[1]Olson,JackR.,“Electrolytictiltsensorandmethodformanufacturingsame”,USpatent,US6802132B1,2004[2]Urano,Mitsuhiro,“Capacitancetypeliquidsensor”,PatentEP1515117A1,2005[3]Zabler,Erich,“Tiltsensor”,PatentEP0768513A2,1997**大學英文文獻原文及翻譯一種精確測量傾斜角度的光學傳感器摘要本文主要介紹了一種新型光學傳感器，它可以同時準確地測量傾斜角或兩軸傾斜角度。這種傳感器是基于激光干涉原理，因此具有很高的精度。設計制作了一個傳感器的模型來論證這個新的方法，這是一個光電傳感器,傳感器中沒有移動的部分。由正交于鉛垂面的流動水平面提供參考面。傳感器和絕對水平面之間的角度隨著被測量的物體傾斜而改變，這些變化反映在條紋圖案的中心位置的轉移方式。不同的干涉條紋的中心位置隨傾斜角的變化而改變。干涉條紋圖案進行記錄和處理，轉化為兩軸、水平和垂直傾斜角度。當使用1024*1024像素的傳感器時，測量范圍為700弧秒，其精度可高達+/-1弧秒。關鍵詞：傾斜角度傳感器，傾斜儀，激光干涉I介紹市場上目前有幾種類型的商業傾斜角度測量傳感器。有些是角度傳感器，有些是傾斜儀，它們的工作原理不同。電解液體、電容和鐘擺是現在大多數傾斜角度傳感器和傾斜儀的三個主要工作原理。在這里，我們提出了一種新的光學方法，建立了一個用激光、光學元件和圖像傳感器的光電傳感器，它可以同時做精確的傾斜角度測量，不需要進行機械的移動，其工作原理是基于光學干涉，相干激光作為光源。光線通過一個裝滿液態油的玻璃油盒。由正交于鉛垂面的流動水平面提供參考面。當激光束穿過油箱有兩束光線反射回來，一束是液體的表面產生的，另一束是容器玻璃產生的，干涉條紋就是由這兩條光線形成的，條紋圖案將隨著傾斜角度的變化產生相應的變化，條紋圖案采集和處理后將反映傾斜角度信息，光學工作原理使它不受磁場的影響。該傳感器可以同時測量兩軸傾角。流動的水平面確保了參考面是一個絕對的水平面。高靈敏度光學干涉測量原理，保證了較高的精度。II原理圖1說明了工作原理示意圖，O點是光線擴大鏡頭的焦點，O點可以看作是點光源，它發出球面波。由于地球重力的影響，液體油面始終保持水平，因此用油面作為參考平面。該容器是玻璃材料的。當傳感器被放在目標表面時，其底部表面將連同目標對象一起傾斜。圖1測量原理工作示意圖從油面和玻璃表面射出的光將干涉形成圓形圖案（見圖4）。傾斜角度可以通過圓形圖案中心位置的改變測量得出。P是點O在玻璃和空間之間形成的鏡像，點Q則是點O在油和空氣之間形成的鏡像，油—空氣平面代表了水平面。當使玻璃面平行油面，點P和點Q在垂直于油面的同一條線上，這條線也是光學系統的軸線。邊緣與共同中心圓形邊緣。當油箱傾斜玻璃表面有一對以油面的傾斜角，這是同心圓圖案。當油盒傾斜時，玻璃面相對于油面有個傾斜角。（1）其中n是玻璃的折射率。當傾斜角度很小，上面的方程可以簡化為 （2）我們可以從和得到以下方程：（3）其中是圓條紋中心的位置，

D是接收屏幕到油箱玻璃表面的距離，H是玻璃和油的厚度，

n是玻璃和油折射率（因為玻璃和油的折射率非常接近，這里假設它們相等）。

假設折射率nD遠遠大于h，因此相對于來說h可以忽略不計。(4)從方程（4）可知，一旦裝置安裝好后，n,d,h是固定的。令,為系統常量，系統參數可以通過校驗過程獲得。因此方程(4)可以寫成（5）其中可以通過圖像處理技術計算出,由此可以得出值。III.傳感器的描述圖2顯示了傳感器的光學頭部詳細布局。它包括激光1，擴束2，光束分離器3，平面鏡4和液體油盒5。一個點光源發出球面波，這束光線穿過油箱。這束光線分別被玻璃表面和油的表面反射，兩束不同路線的光將再次相遇再次相聚。如果點光源相干長度大于長的光程差，這兩束光線將產生干涉形成環形條紋。當一個表面發生傾斜，圓形條紋中心將相應地轉變。當光學路徑變化，條紋將相應的出現或者被吸收。條紋變化發生在一個相對應的光程差，其中為光源的波長。圖2光學傳感器布局如圖2所示，激光發射激光束1。激光束通過擴束2被擴大，形成一個球形波前束，隨后這束光線垂直穿過液