長基線恒星光干涉技術(shù)中延遲線系統(tǒng)地設(shè)計與

吳楨等:長基線恒星光干涉技術(shù)中延遲線系統(tǒng)的設(shè)計與實驗中國科學(xué):物理學(xué)力學(xué)天文學(xué)2012年第42卷第2期圖7實驗系統(tǒng)示意圖Figure7Schematicdiagramofexperimentalsystem.本預(yù)計采用裝調(diào)好后的系統(tǒng)(如圖6)進行實驗;實驗發(fā)現(xiàn)從雙頻激光干涉儀出來的光束經(jīng)拋物面反射鏡反射后其偏振特性被改變,雙頻激光干涉儀無法探測到,因此我們只好將雙頻激光干涉儀自帶的平面反射鏡直接安裝在PZT系統(tǒng)上(如圖7),但是工作原理是一樣的.采用這樣的實驗系統(tǒng),我們首先測試了精密運動平臺的跟蹤誤差.只有精密運動平臺更新運動速度、PZT不動的情況下,測試結(jié)果如圖4,表明精密運動平臺的跟蹤誤差為5m.假設(shè)觀測中心波長為500nm,帶寬為5nm,為了使條紋可見度的損失小于1%,延遲補償?shù)木葢?yīng)好于相干長度的十分之一,則光程差應(yīng)該維持在±3m內(nèi).小車的跟蹤速度每秒鐘更新一次,PZT系統(tǒng)補償頻率每秒鐘40次對上述的運動曲線進行跟蹤.圖8為最終的跟蹤誤差,從圖8中可以看出,除了個別點的跟蹤誤差比較大(三角所示,大約為1m),整個系統(tǒng)的跟蹤精度是非常高的.這樣的跟蹤精度滿足±3m的要求.5結(jié)論通過實驗,在PZT校正頻率為40Hz時,其跟蹤誤差在短時間內(nèi)基本處于±1m以內(nèi),滿足了實際觀測的要求.由于軟件采用動態(tài)鏈接庫方式獲取數(shù)據(jù),圖8系統(tǒng)跟蹤誤差(單位:counts,1counts為50nm)Figure8Trackingerrorofthesystem(unit:counts,1countsis50nm).并通過網(wǎng)絡(luò)方式進行數(shù)據(jù)傳輸,經(jīng)過測試,網(wǎng)絡(luò)傳輸?shù)臅r延會到達10ms以上,動態(tài)鏈接庫獲取位置數(shù)據(jù)的程序段,執(zhí)行時間也在幾個ms級,因此限制了整個控制系統(tǒng)的帶寬,無法再大幅度提高控制頻率,因此在現(xiàn)有的軟實時控制模式下要進一步提高跟蹤精度,難度很大.國外已經(jīng)建成的干涉儀延遲線控制系統(tǒng)都是基于硬實時來實現(xiàn)的,控制頻率幾千Hz.延遲線要達到理想控制目標,應(yīng)該考慮硬實時的方法.本課題的研究表明我們采用的二級補償系統(tǒng)是可行的,下一步我們將繼續(xù)提高精密運動平臺的跟蹤精度以及運動的穩(wěn)定性;改變控制系統(tǒng),采用硬件實時控制.參考文獻王正明,徐家?guī)r,蕭金宏,等.天文光干涉測量.北京:科學(xué)出版社,1996LawsonPR,ThompsonBJ.SelectedPapersonLongBaselineStellarInterferometry.Bellingham,WA:SPIEOpticalEngineeringPress,1997GarciaPJV,HenningT,GlindemannA.TheveryLargeTelescopeInterferometer––ChallengesfortheFuture.Dordrecht:Springer,2007LawsonPR.Principlesoflongbaselinestellarinterferometry.CourseNotesfromthe1999MichelsonSummerSchool.Pasadena:NationalAeronauticsandSpaceAdministration,JetPropulsionLaboratory,CaliforniaInstituteofTechnology,1999MonnierJD.Opticalinterferometryinastronomy.RepProgPhys,2003,66:789–857JankovS.Astronomicalopticalinterferometry1.MethodsandInstrumentation.SerbAstronJ,2010,181:1–17MartinC.RecentastrophysicalresultsfromtheVLTI.Messenger,2005,121:52–55LawsonPR.Advancesinsciencewithstellarinterferometers2004–2006.ProcSPIE,2006:626801MonnierJD,ZhaoM,PedrettiE,etal.Imagingthesurfaceofaltair.Science,2007,317(5836):342–345ZhaoM,GiesD,MonnierJD,etal.FirstresolvedimagesoftheeclipsingandinteractingBinarybLyrae.AstrophysJ,2008,684:L95–L98YoungJS,BaldwinJE,BasdenAG,etal.AstrophysicalresultsfromCOAST.ProcSPIE,2001,4838:369–378Karovska

M.Interferometricsurveysandresultsonvariablestars:Nowandinthefuture.JAmAssocVariableStarObs,2006,35(1):34–42LaneBF,MuterspaughMW.Differentialastrometryofsubarcsecondscalebinariesatthepalomartestbedinterferometer.AstrophysJ,2004,601:1129–1135BainesEK,McAlisterHA,TenBrummelaarTA,etal.\o"|Subgiantstars|Astrophysicalresults|CHARA|Giantstars|Dwarfstars|CHARAClassic|NearInfrared|"ElevenexoplanethoststarangulardiametersfromtheCHARAarray.AstrophysJ,2009,701(1):154–162DavisJ,JacobAP,RobertsonJG,etal.\o"|Cepheidvariables|SUSI|Astrophysicalresults|Visibledomain|"ObservationsofthepulsationoftheCepheidlCarwiththeSydneyUniversityStellarInterferometer.MonNotRAstronSoc,2009,394(3):1620–1630KishimotoM,H?nigSF,AntonucciR,etal.\o"|ActiveGalacticNuclei|Keck|Astrophysicalresults|NearInfrared|"Exploringtheinnerregionoftype1AGNswiththeKeckinterferometer.AstronAstrophys,2009,507(3):L57–L60DavisJ,TangoWJ,BoothAJ,etal.TheSydneyUniversityStellarInterferometer-ⅠTheinstrument.MonNotRAstronSoc,1999,303:773–782ArmstrongJT,MozurkewichD,JrickardL,etal.Thenavyprototypeopticalinterferometer.AstrophysJ,1998,496:550–571ShaoM,ColavitaMM,HinesBE,etal.ThemarkⅢstellarinterferometer.AstronAstrophys,1988,193:357–371ColavitaMM,WallaceJK,HinesBE,etal.Thepalomartestbedinterferometer.AstrophysJ,1999,510:505–521McAlisterHA,BagnuoloWG,BrummelaarTA,etal.TheCHARAarrayonMountWilson.ProcSPIE,2000,4006:465–471ColavitaMM,WizinowichPL.KeckInterferometerupdate.ProcSPIE,2003,4838:79–88吳楨.基于光干涉技術(shù)的高精度高分辨率成像.10000個科學(xué)難題·天文卷.北京:科學(xué)出版社,2010.955–959duForestoVC.Groundandspacebasedinterferometry.BullSocRSciLiege,2005,74:357–358DerieF.VLTIdelaylines:Design,developmentandperformancerequirements.ProcSPIE,2000,4006:25–30HogenhuisH,VisserM,DerieF.CommissioningoftheVLTIdelaylinesonmountparanal.ProcSPIE,2003,4838:1148–1154李超.邁克爾遜式恒星干涉儀延遲線試驗平臺控制系統(tǒng)設(shè)計與實現(xiàn).碩士學(xué)位論文.北京:中國科學(xué)院研究生院,2010

Designandexperimentofthedelaylinesystemforlongbaselinestellarinterferometry?WUZhen1,2*,LIChao1,2,3,LINXieJia1,2,3,ChenYi1,2&WANGJiaNing1,21NanjingInstituteofAstronomicalOptics&Technology,NationalAstronomicalObservatories,ChineseAcademyofSciences,Nanjing210042,China;

2KeylaboratoryofCASforAstronomicalopticsandtechnology,ChineseAcademyofSciences,Nanjing210042,China;

3GraduateUniversityofChineseAcademyofSciences,Beijing100049,ChinaOpticaldelaylinesystemusedtocompensatethegeometricopticalpathdifferenceisoneofkeysubsystemofthelongbaselinestellarinterferometer.AtwostagescompensationdelaylinesystemdevelopedbyNanjingIns