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1THEAPPLICATIONOFADVANCEDROBOTICSANDSENSORTECHNOLOGIESTOTHEPRESERVATIONOFTHEUSSCONSTITUTIONJEFFREYCOLESTEVENDUBOWSKYNATHANRUTMANCRAIGSUNADADEPARTMENTOFMECHANICALENGINEERINGMASSACHUSETTSINSTITUTEOFTECHNOLOGYCAMBRIDGE,MAO2139USAABSTRACTTHEAPPLICATIONOFROBOTICSANDADVANCEDSENSORTECHNOLOGYTOSOLVEIMPORTANTPROBLEMSINTHEFIELDSOFARCHITECTURAL,ARCHAEOLOGICALANDARTCONSERVATIONANDPRESERVATIONISDISCUSSEDTHEUSSCONSTITUTIONISCONSIDEREDASADEMONSTRATIONPROJECTOFTHISWORKTHREEIMPORTANTAPPLICATIONSOFTHISTECHNOLOGYTOTHEPRESERVATIONOFTHESHIPAREDISCUSSEDADESIGNISPRESENTEDFORONEOFTHESEAPPLICATIONSAKEELDEFLECTIONMEASUREMENTSYSTEMITISCONCLUDEDTHATROBOTICSANDADVANCEDSENSORTECHNOLOGYOFFERSSUBSTANTIALPROMISEOFHAVINGIMPORTANTBENEFITSFORTHERESTORATIONANDPRESERVATIONOFIMPORTANTHISTORICANDARCHITECTURALSITESANDMOMENTSINTRODUCTIONTHISPAPERREPORTSONARESEARCHPROGRAMINWHICHWEAREEXPLORINGTHEAPPLICATIONOFRECENTLYDEVELOPEDTECHNOLOGIESINROBOTICS,SENSORSANDREALTIMECOMPUTERSTOSOLVEIMPORTANTPROBLEMSFACEDBYTHEARCHITECTURAL,ARCHAEOLOGICALANDARTCONSERVATIONANDPRESERVATIONCOMMUNITIESOVERTHEPASTDECADE,SIGNIFICANTADVANCEMENTHASBEENMADEINTHETECHNOLOGYOFROBOTICS,SENSORSANDCOMPUTERS,ATSUBSTANTIALCOSTSTOGOVERNMENTAGENCIESSUCHASNASA,THEDEPARTMENTOFDEFENSE,ANDTHEDEPARTMENTOFENERGY17THISTECHNOLOGYHASIMPORTANTPOTENTIALAPPLICATIONINTHEAREAOFPRESERVATIONANDCONSERVATIONOFHISTORICANDARTISTICTREASURES,ANDINPARTICULARMONUMENTSANDFIELDSITESAMONGTHETASKSTHATTHECONSERVATIONCOMMUNITYISCALLEDONTOPERFORM,THEREEXISTANUMBERTHATCOULDGREATLYBENEFITFROMTHEAPPLICATIONOFADVANCEDROBOTICSANDGRADUATERESEARCHASSISTANTPROFESSOR2SENSORTECHNOLOGIESSOMETRADITIONALCONSERVATIONWORKHASRESULTED,UNAVOIDABLY,INTHEDETERIORATIONOFTHESITEFOREXAMPLE,CONSERVATIONWORKONSOMELARGEMONUMENTSHASUSEDSCAFFOLDINGANCHORSINSTALLEDINHOLESDRILLEDINTOTHEMONUMENTITSELFSOMECONSERVATIONTASKS,SUCHASDETAILEDSITEMAPPINGS,REQUIREAGREATDEALOFTEDIOUSWORKMANYTASKSARELIMITEDDUETOSAFETYCONSIDERATIONSINDEED,SOMETASKSTHATAREOFINTERESTTOTHECONSERVATIONCOMMUNITYSIMPLYARENOWIMPOSSIBLEORIMPRACTICALTOEXECUTEDUETOSAFETYCONCERNSANDACCESSLIMITATIONSFINALLY,MANYHIGHLYDESIRABLECONSERVATIONPROCEDURESARESIMPLYTOOEXPENSIVEUSINGCURRENTTECHNIQUESADVANCEDROBOTICSANDSENSORTECHNOLOGIESMAYBEABLETOSOLVESOMEOFTHESEPROBLEMSWORKINGWITHRESEARCHERSANDPRACTITIONERSINTHECONSERVATIONANDPRESERVATIONFIELDSHASMADEITCLEARTOUS,THATWHILETECHNICALCAPABILITIESAREVERYIMPORTANT,THEACCEPTANCEOFROBOTICSANDSENSORTECHNOLOGYTOTHESEFIELDSWILLREQUIREAHIGHLYSUCCESSFULANDVISIBLEDEMONSTRATIONPROJECTFROMOURSTUDIES,WEHAVEIDENTIFIEDTHEUSSCONSTITUTIONASTHEIDEALSITEFORSUCHADEMONSTRATIONPROJECTOURPRELIMINARYWORKHASSHOWNTHATTHEREAREANUMBEROFPOTENTIALTASKS,IMPORTANTTOTHEPRESERVATIONOFTHESHIP,THATADVANCEDTECHNOLOGYCOULDPERFORMMOREEFFECTIVELYTHANCURRENTMETHODSINSOMECASESTHETECHNOLOGYCOULDOFFERGREATERSAFETYORISPOTENTIALLYMORECOSTEFFECTIVEINTHISPAPERWEDESCRIBETHREEOFTHESEPOTENTIALAPPLICATIONSANDTHEIRPOSSIBLESOLUTIONSTHEFIRSTISANAUTOMATEDINSITUHOGMEASUREMENTSENSORSYSTEMTOCONTINUOUSLYMONITORTHESHAPEOFTHESHIPSKEELWHILESHEINTHEWATERTHESECONDISAROBOTICSYSTEMTODETECTROTINTHESHIPSINTERNALSTRUCTUREBENEATHITSROCKANDCHAINBALLASTTHEFINALISAROBOTICDEVICETOINSPECTTHESHIPSMASTANDRIGGINGFORDETERIORATIONITSHOULDBERECOGNIZEDTHATADEMONSTRATIONONTHEUSSCONSTITUTIONWOULDALSOBENEFITTHEGROWTHOFROBOTICSITWOULDPROVIDEACHALLENGINGANDEXCITINGTESTBEDFORTHETECHNOLOGYUNDERACTUALFIELDCONDITIONSHOGMEASUREMENTSYSTEMTHEKEELOFTHESHIPCHANGESSHAPEOVERTIMEDUETOTHEEFFECTSOFWATERANDLOADINGINORDERTOREDUCETHISHOGANDTHEREBYEXTENDTHELIFEOFTHEKEEL,ITISNECESSARYTOKNOWTHESHAPEOFTHECURVEACCURATELYPRESENTLY,HOGMEASUREMENTMETHODSINCLUDEUSINGDIVERSWHOMANUALLYMEASURETHEDISPLACEMENTOFTHEKEELFROMAFIXEDREFERENCELINE,ORINDIRECTMETHODSFROMINSIDETHESHIPSHULLWEHAVEDEVELOPEDFIGURE1THEUSSCONSTITUTION3ASYSTEMBASEDONDISTRIBUTEDSENSORTECHNOLOGYFORQUICKLY,ACCURATELY,ANDINEXPENSIVELYDETERMININGTHEKEELSHAPESIMPLYPUT,THESYSTEMMEASURESTHEWATERPRESSUREATASMALLSETOFLOCATIONSSEVENONTHEKEELFROMTHESEMEASUREMENTSACOMPUTERACCURATELYINFERSTHESHAPEOFTHEKEEL,INREALTIMETHESYSTEMISABLETOUSEASMALLNUMBEROFSENSORSBYAPPLYINGCHEBYSHEVTHEORYTODETERMINETHEOPTIMALLOCATIONSFORTHEPRESSUREMEASUREMENTSTHESELOCATIONSARESELECTEDTOMINIMIZETHEMAXIMUMMEASUREMENTERRORTHEWATERPRESSUREONTHEKEELISCONVERTEDTOANAIRPRESSURESIGNALBYFIXEDKEELPRESSURETRANSDUCERS,SEEFIGURE2PRESSURESENSORSTHENMEASURETHEPRESSUREATTHEKEEL,WHICHISADIRECTFUNCTIONOFTHEDEPTHTHESEPRESSURESENSORSAREEXPOSEDONLYTOAIRPRESSUREANDARELOCATEDATANONBOARDMEASUREMENTCOMPUTERWITHINTHESHIPTHISDESIGNPUTSALLELECTRONICHARDWAREELEMENTSINA“SHIRTSLEEVE”ENVIRONMENTITPERMITSTHEUSEOFINEXPENSIVECOMMERCIALCOMPONENTSANDMAKESMAINTENANCEANDCALIBRATIONOFTHESYSTEMEASYDIFFERENTIALPRESSURESENSORSAIRHOSESCOMPUTERREFERENCEPRESSUREWATERPRESSURE/AIRPRESSURETRANSDUCERSKEELDATAACQUISITIONINTERFACEFIGURE2THEHOGMEASUREMENTSYSTEMOVERVIEWSENSORSONTHEKEELREPORTPRESSUREATSPECIFICLOCATIONS,FROMWHICHTHECOMPUTERCALCULATESTHEKEELSHAPETHEKEELPRESSURESARECOMPAREDTOAREFERENCEPRESSUREATONEENDOFTHESHIPUSINGTHESEDIFFERENTIALPRESSURESENSORSTHISALLOWSACCURATEMEASUREMENTSOVERTHE4SMALLRANGEOFTRANSDUCERDEPTHSFROMTHESEFINITEDEPTHMEASUREMENTSTHECOMPUTERCALCULATESTHESHAPEOFTHEKEEL,SEEFIGURE3KEELPOSITIONFT4202468101214FIGURE3KEELSHAPEINFERREDFROMSEVENMEASUREMENTSTHEBARSARESENSORREADINGS,THESOLIDLINEISDIVERMEASUREDDATA,ANDTHEDASHEDLINEISTHECURVESHAPEINFERREDFROMTHESENSORSSUBBALLASTINSPECTIONTHEAREAUNDERNEATHTHEBALLASTINTHEHOLDOFTHESHIPISSUBJECTTODAMP,ROTINDUCINGCONDITIONS,SEEFIGURE4ITISIMPOSSIBLEFORWORKERSTOINSPECTTHISAREAEXCEPTDURINGDRYDOCK,WHENTHEBALLASTISREMOVEDINORDERTOFACILITATEMOREFREQUENTINSPECTION,THEUSEOFASMALLAUTONOMOUSFIELDROBOTTOPERFORMTHISINSPECTIONISBEINGCONSIDERED,SEEFIGURE5THEROBOTWOULDCARRYAVIDEOCAMERAANDSENSORSDESIGNEDTODETECTANDMEASUREROTKEELSONSISTERKEELPROPOSEDBALLASTSUPPORTBALLASTINSPECTIONSURFACESDRAINKEELHULLLIMBERSTRAKEFIGURE4SUBBALLASTAREATHEAREAISONLYEXPOSEDDURINGDRYDOCKANAUTOMATEDINSPECTIONSYSTEMTHATCANWORKUNDERNEATHTHEBALLASTWOULDBEVERYUSEFUL5THEINSPECTIONTASKISFURTHERCOMPLICATEDBYTHEPRESENCEOFDIAGONALRIDERS,WHICHPERIODICALLYCUTOFFSECTIONSOFTHESUBBALLASTAREATHEROBOTWOULDHAVETOCLIMBOUTOFTHEAREA,OVERTHERIDER,ANDTHENBACKDOWNINTOTHENEXTSECTIONFIGURE5ACONCEPTFORASUBBALLASTINSPECTIONROBOTVARIOUSASPECTSOFTHISPROBLEMAREBEINGSTUDIED,INCLUDERAPIDMECHANICALROBOTICDESIGN,ROBUSTPLANNINGALGORITHMS,ADVANCEDSENSORTECHNOLOGY,ANDCONTROLSYSTEMSTHERESULTSOFTHISWORKWOULDBEUSEFULINAWIDEVARIETYOFFIELDAPPLICATIONS,INCLUDINGOTHERCONSERVATIONTASKSMASTANDRIGGINGINSPECTIONFINALLY,THEMASTSOFTHESHIPAREALSOSUBJECTTOROTANDNEEDPERIODICINSPECTIONTHECURRENTINSPECTIONMETHODHASAWORKERCLIMBTOEXTREMEHEIGHTS,AND/OREXPENSIVEANDUNSIGHTLYCRANESTOINSPECTTHEUPPERSECTIONS,SEEFIGURE6THETOPMOSTSECTIONSARENEVERINSPECTEDAROBOTICSOLUTIONMIGHTAGAINBEUSEFULWEAREEXAMININGTWOAPPROACHESTOTHISPROBLEM,SEEFIGURE7FIRSTISACLIMBINGROBOTCONCEPTTONAVIGATETHECOMPLEXRIGGINGANDCLIMBTHEMASTSTHISAPPROACHCHALLENGESPRESENTTECHNOLOGYHOWEVER,WEHAVEDEVELOPEDASIMPLECLIMBINGROBOTANDARESTUDYINGITSPOTENTIALEXTENSIONTOSUCHTASKSASMASTINSPECTIONTHESECONDAPPROACHISLONGREACHMANIPULATORS,SEEFIGURE7PROBLEMSRELATINGTOTHECONTROLOFLONGREACHFLEXIBLEMANIPULATORSYSTEMSARESIMILARLYUNDERSTUDYINOURLABORATORYINCONNECTIONWITHNASASSPACESTATIONFREEDOM6MASTINSPECTIONFIGURE6THECOMPLEXITYOFTHECONSTITUTIONSRIGGINGANDHEIGHTOFHERMASTS220MAKEINSPECTIONDIFFICULTTRANPORTER/CONTROLUNITINTELLIGENTINSPECTIONDEVICEARTICULATEDDEPLOYABLEELEMENTSCOMPOSITEMATERIALSAUTONOMOUSCLIMBINGINSPECTIONROBOTCCDCAMERAULTRASONICSENSORRFTRANSMITTER/RECEIVERCONTROLFIGURE7TWOMASTINSPECTIONROBOTCONCEPTSCONCLUSIONSTHISPAPERREPORTSONARESEARCHPROGRAMTOEXPLORETHEAPPLICATIONOFROBOTICS,SENSORSANDREALTIMECOMPUTERTECHNOLOGIESTOSOLVEIMPORTANTPROBLEMSFACEDBYTHEARCHITECTURAL,ARCHAEOLOGICALANDARTCONSERVATIONANDPRESERVATIONCOMMUNITIESTHEUSSCONSTITUTIONIDENTIFIEDHASBEENIDENTIFIEDASTHEIDEALSITEFORADEMONSTRATIONPROJECTOFTHISWORKTHISPAPERDESCRIBESTHREEPOTENTIALLYIMPORTANTAPPLICATIONSOFTHISTECHNOLOGYTOTHEPRESERVATIONOFTHESHIPWEBELIEVETHATSUCHADVANCEDTECHNOLOGYCOULDPERFORMTHESETASKSMOREEFFECTIVELY,SAFELY,ANDWITHLESSTOTALCOSTTHANCURRENTMETHODSACONCLUSIONOFOUR7WORKTODATEISTHATROBOTICSANDADVANCEDSENSORTECHNOLOGYCOULDHAVEANIMPORTANTIMPACTOFTHEFIELDOFTHERESTORATIONANDPRESERVATIONOFIMPORTA