ai-aerospace/ams_data_full_2000-2020 huggingface dataset:
2OOO 1800 1600 1400 E1200 1000 800 600 400 200 0IComplete Nanorover Assembly: I ! i i Mobility Components (forreference)i TimefromPDRtoCDR Figure9.Complete Nanorover Assembly MassHistory (Mobility Components Historyincluded forreference onlytoFigure8) Lessons Learned Uponadetailed inspection ofthetrends,thenormalmassmargins thatwereplanned forattheoutset wereveryinadequate. Theexpected growthforasmallmasssystemneedstobemuchgreaterthanthe AIAAspecification suggests. Thelowestmassrangeofthespecification isfromzerotofiftykilograms (seeFigure7).Thisrangeneedstobebrokenintosmallergroups,withthelowestrangebeingfromzero tofivekilograms. Notethatfivekilograms forthehighendoftherangerepresents themassofthe completed systemwithcontingency. Several examples ofthereasons forthelargepercentage mass growthontheNanorover arelistedbelow: 1.Themotorassemblies werecompleted atamassofthreegrams.Whentheneedfortheunpowered andstaticrotorpositionsensingwasidentified, aHallsensorassembly wasaddedtothemotors.The sensorassembly masswasalsothreegrams,ora100%massgrowthforthemotors.Thiscondition wouldneverbethecaseforatypicalsizedmotoraround25millimeters indiameter. Themotormass wouldbeabout100gramsandtheaddition ofasensorassembly wouldaddaround5%tothemotor mass. 2.Theaddition oftherotorpositionsensingonthemotorsincreased thecablingtothemotorsby200%. Thiswasamassincrease of90gramstotheNanorover system(ortheequivalent ofanentire instrument). 3.Thegearbox assemblies hadanearlymassof4.5grams.Themobility systemdesignmatured to requirethegearbox outputshafttocarryamoment loadof1.2N*m.Thischangerequired an additional outputbearingtocarrythemoment load.Themassincrease was2.5grams,ora55% increase. NASA/CP--2002-211506 112
Machining tolerances forextremelysmallcomponents cannotbemaintained atthesamerelative magnitudeastheycanforlargerparts.Thiscanresultinthefinalmachinedcomponents havingalarge variationfromtheCADsystemdesignmass. Thethermalenvironment andthermalcontroldesignmayoftenleadtoalargetemperature swingina smallsystem.Theinternalheatcapacityofasmallsystemislowbecausethereislittlemass.Theinternal volumewilloftennotallowtheuseofstandardthermalcontroldevices.Thissituationmaybemitigatedin thefutureassmallerthermalcontrolcomponents becomeavailableforspacecraftuse. Thevibrationenvironment forsmallcomponents candrivethedesignsignificantly duetothecomponent's tendencytorespondtohigherfrequencies intherandomvibrationspectrum.Thevibrationresponseof thecomponents canleadtolargedisplacements thatoftencannotbetolerated.Theadditionoffeatures toreducedisplacement magnitudes ortomaintainmaterialstresseswithinallowablerangeswillrequire additionalmass.Thisadditionalmassinasmallsystemcanbedisproportionately higherthanalarger systembecausetheaccelerations andloadingaremarkedlyhigher. Theelectronicsystemmassinasmallsystemisverysensitivetochangesinthecircuitdesign.Small changesinthecomponent countaddsignificantmassduetotheadditionalneededcircuitboardarea.If thethermalenvironment isasextremeastheNanoroverrequirements, additionaltimeandmassmargin needtobeaddedtoallowfortheidentification oftheelectroniccomponents thatwillfunctionatthe temperature extremesoftheassembly.Thedetermination ofthecomponents thatwillmeetthefunctional needsoftheelectronics subsystem mustoccurveryearlyintheprojecttopreventsignificantlatemass growththatwillaffecttheentiresystem. Themasscontingency plansonprojectswithasmallsystemmassneedtobegreaterintheearlystages toaccountforthemanyitemsthatwillcausealargepercentage growthofthesystemmass.Figure10 showsarecommendation fromthisauthorforamodification totheAIAAspecification andTable1lists thesameinformation intabularform.Thesmallestmassgroupingforestimatingshouldbezerotofive kilograms.Futuredatafromprogramswithmassesintherangeabovefivekilogramsmayindicatethat thereneedstobeadditionalmassgroupingsbetweenfiveandfiftykilograms.Thedesignofsmall spacecraftsystemsorcomponents requiresadditionalattentiontotheissueslistedabovethatdonot significantly affectlargerdevicesandassemblies. Smallsystemsaremoresensitivetothematurity changesthatoccurinthenormaldesigncyclethanlargersystems.Therecommended specification modification inFigure10providesthemassgrowthcapabilityneededforsmallsystemdesigns. 300 25o e200 O 150 t_ 100 0 .... _ Bid CoDR PDR CDR PRR Project Stage Figure10.Recommended Modification totheLowMassGroup ForClass1System Designs ofAIAASpecification G-020-1992 NASA/CP--2002-211506 114
Table1.Recommended Modification totheLowMassGroup ForClass1System Designs ofAIAASpecification G-020-1992 Project Stage Percent Mass Contingency Bid 250 CoDR 100 PDR 60 CDR 25 PRR 0 References BozSharif,EdJoscelyn, BrianWilcox, andMichael R.Johnson "Development ofaMiniature, TwoAxis,Triple-Helmholtz-Driven Gimbal" 34thAerospace Mechanisms Symposium, (May10-12,2000), pp.189-198. Acknowledgements Thisworkwasperformed attheJetPropulsion Laboratory, California Institute ofTechnology, undera contract withtheNational Aeronautics andSpace Administration. Reference hereintoanyspecific commercial product, process, orservice bytradename,trademark, manufacturer, orotherwise doesnot constitute orimplyitsendorsement bytheUnitedStatesGovernment ortheJetPropulsion Laboratory, Pasadena, California. NASA/CP--2002-211506 115
concentricwiththefinalrollDOF.Allsixactuationaxesintersectinasinglepointatthecenterofthe sphere. Figure1.Ranger Wrist Theapproach takenfortool-exchange wastodesignastandardized IEEM(Figure 2)asabasisforall Ranger tools.Eachtoolisboltedpermanently toanIEEM,whichhandles thecouplings between thetool andthemanipulator andbetween thetoolandthetoolstorage device. Initialdesigns 4usedonRNBV-1 werebasedonideasfrommachine-tool tapered colletsandpneumatic couplings. Forthesecond design iteration thegoalsweretoreduce bulk(particularly diameter), improve tolerance tomisalignment, and allowforlargertoolsbychanging thetoolstorage geometry. Figure2.ToolPostandIEEM NASA/CP--2002-211506 119
RPRWrist Thisisthedesignimplemented onthedexterous armsofRNBV-1 in1995,whichisstilloperational. A variantofthiswristisusedonthevideoarmsofRNBV-1 andRNBV-2. Figure3showsacross-section of theforearm andwrist.  __ ................................... _.__ __-_ RollJoint#1 PitchJoint RollJoint#2ToolDrives Figure3.Cross-Section ofRPRWrist Thedrivehardware fortheinitialrolljointcanbelocated anywhere alongitsaxis.Asshown, ithasbeen placedasclosetotheelbowaspossible toreducetheangular inertiaofthewristabouttheelbow.This feature iscommon toallthreewristdesigns discussed here. Thechiefadvantage ofaRPRwristissimplicity. Nearlyallcommercial robotshaveRPRwrists.Thejoint drivesarestructurally serialandcanusemanypartsincommon. Infact,theRNBV-1 wristssharemost basicactuator partswiththeelbows. Thekinematics aresimple; jointanglesarejusttheEulerangles. Ranges oftherolljointsarelimitedbytheallowable twistinthewiringroutedthrough theiraxesrather thanamechanical hardstop.Thepitchjointrangeislimitedbycontact between thewristhousing andthe forearm. Orthogonal RPYRWrist Thisdesignwasintended toaddress several shortcomings oftheRPRwrist.Aforce/torque sensorwas included, thewrist-center totooldistance wasdecreased, andafourth(redundant) DOFwasadded. The RPYRconfiguration alsolackstheRPRwrist'ssingularity inthestraight-out position (pictured inFigure 4).Thegeometry issimilartothatofagyroscope gimbal. YawDrive Force/Torque Sensor :-qi __Roll Joint#2 __ ToolDrives RollJoint#1 PitchDrive Figure4.Cross-Section ofOrthogonal RPYRWrist NASA/CP--2002-211506 123
Notethattheyawaxis(notvisible)isorientedoutofthepagefromthecenterofthewristsphere.The pitchandyawactuatorsareoffsettowardtheelbowusingcabledrives.Thissystemcausestheyawdrive tooperatedifferentially, i.e.theyawangleachievedisthedifferenceoftheyawandpitchactuator positions.Thelimitationsonpitchandyawrangeareduetocontactbetweenhousings.Thefinalrolljoint rangeisunlimitedsincenowiringpassesthrough. Compared totheRPRwrist,theoRPYRwristismuchmorecomplexandintegrated. Thepartcount increasedconsiderably. Wrist-to-tool distancewasgreatlyimprovedduetothedrivelayout,although forearmlengthincreasedsomewhat asaconsequence. Inclusionoftheforce/torque sensoralso contributed toforearmgrowth. Theorthogonal RPYRwristwasneverbuilt.Asthedetaileddesignprogressed, itsbulkincreasedand angularworkspace decreased, largelyduetothecomplications associatedwithcabledrives.Ultimatelyit wasshelvedinfavoroftheskewRPYRdesign. SkewRPYRWrist Changing theanglebetween thefirstrollaxisandthepitchaxisfrom90degto45degbrought twomain advantages totheskewwrist(Figure 5).Interference ofthetoolwiththeforearm wasmuchreduced, increasing therangeofpitchtravel.Also,the45deg"layback" angleoftheactuator decreased thefrontal areaofthewristsignificantly. \ \  ' /wJointPitchJoint\_-?J_-_-x_¢',_ Joint#2  .................................. _/ /_'....Tool Dr,ves RollJoint#1 Force/Torque Sensor Figure5.Cross-Section ofSkewRPYRWrist Notethatamoretypicalworking position ofthepitchjointwouldorienttheyawaxisoutofthepage(e.g. Figure1);ithasbeendepicted rotated 90degtoshowtheyawactuator incross-section. Thewristyaw driveisdirectinthiswrist,notdifferential, andthecabledriveshavebeeneliminated. Thepitchjoint rangeislimitedonlybywiringtwist,whiletheyawrangeissetbyhousing contact. Bothvaluesare increased substantially overtheorthogonal RPYRwrist.Thewristissmaller laterally andlengthwise, reducing forearm lengthbyover20%.Theforce/torque sensor isclosertothewristcenterbyasimilar amount, improving itsabilitytodiscriminate contact forces. Mechanically, theskewwristissimpler than theorthogonal design, thoughstillcomplex compared totheRPRwrist. Table1illustrates theadvantages oftheskewwristdesign intermsoflargeangular jointrangeand compact packaging. NASA/CP--2002-211506 124
Table1.WristParameters Maximum lateral dimensionWrist-center to ToolBase distanceRollJoint #1rangePitch Joint rangeYawJoint rangeRollJoint #2range RPR 18cm(7in) 38cm(15in) 576deg220deg N/A 576deg oRPYR 27cm(11in) 12cm(4.8in)576deg270deg 90deg co sRPYR 24cm(9.5in) 12cm(4.8in)576deg540deg 220deg oo Comparison ofJointWorkspace andSinqularities Inthesewrists,singularities arenotafunction oftherollangles:neitherroll#1norroll#2changes the internalgeometry ofjointaxes.Thusallsingularities canbelocatedusingpitchandyawangles(where present). Figure6mapsthesingularities andshowsthepitchandyawjointlimits(singularities outside jointlimitsarenotproblematic). ,8°°-: RPRWrist 135°-.2 90°- 45°- Yaw0o. .45°. _90°. .135°. -180° ....'....._'o'o"__'so 'o:_o9'oo'"',_0o _180°.135° 135° PitchPitch,Roll#1,Roll#2Orthogonal RPYRWrist180°_ 135°- 90°- Roll#2,Pitch 45°" - iiYawoo- ........ I 45o I .90°. -135°.Roll#2,Pitch I I --I i I I x......I--I i I i YawPitch -180° Ii iiii iiilllll iiiii ii i 2:0°'%°-,_oo-,!_5o'0o.:,'_o''o''"....'45° 9(1° Pitch Yaw0o _45°. _90°. _135°. .180°II I Pitch'i I180°7 13501  ,,of 45J/ I ....... f...... I ', :I I i Roll#2YawI I I ,Roll#2 Roll#2 Yaw Roll#2 i_t,_ll=_l,_ lq,_=l,,,,i,,,,i,,,_l,,, fi,_f,p,,_l ,,,,I,,,,i,_ -360°-315°-270°-225°-180°-135°-90°-45° 0° 45° 90° 135°180° _Yaw,fRoll#1 \-Workspace x-Toolaligned withforearm ....Redundancy lostin oneormoreaxis; constrained axesare indicated o-Singularity: wrist dropsto2-DOF Pitch Figure6.WristWorkspace Comparison NASA/CP--2002-211506 125
Coordinate systems foreachwristhavebeenchosen usingtheDenavit-Hartenberg convention 12. Alignment ofthetoolwiththeforearm ("straight-out" attitude) isindicated byan"X."The"notches" inthe sRPYR workspace areduetostructural interference between thetoolandforearm. TheRPRwristhasasingularity atthestraight-out position, dividing theworkspace intotwobranches. Sincearegionofroughly 5degradiusaround thesingularity cannotbetraversed, theusableRPRjoint workspace iseffectively cutto105degfromthemechanically-allowed 220deg.Singularities inthe oRPYR wristareoutside theworkspace andcanbeneglected. ThoseinthesRPYR workspace occurin theconfiguration ofFigure5,whenallaxeslieinasingleplane.However, duetoredundancy thesame toolattitudes canbeobtained withnon-singular configurations. Figure6illustrates thegainsinjointworkspace obtained byadvances inwristmechanical layout.The nextquestion ishoweffectively theimprovements madeinjointspacetranslate toincreased rangeof motionintoolcoordinates, i.e.,Eulerangles(0,e,_). Comparison ofToolWorkspace TheRPRwristhasnoredundancy; itsjointangles mapdirectly totheEulerangles. Thelimitsintool attitude arejustthejointlimits:¢range=576deg,erange=5degto110deg,_range=576deg. Fortheothertwowrists,thesecond rolljointisaligned directly with_anditsrangeisunlimited; hence therangeof_isunlimited, eisdetermined onlybythepitchandyawangles, and¢depends uponroll#1, pitchandyaw.Duetoredundancy, foreverycommanded angleethereisarangeofpossible combinations ofpitchandyaw.Thosejointsgiveacontribution to¢aswell.Thecontroller canselect whichcombination touse,soforeverycommanded ethereisarangeof¢whichcanbeaddedtothe contribution fromroll#1.Thusthe¢rangeforthewristasawholeisthesumoftheroll#1jointrangeand therangeof¢available frompitchandyawforthecurrent commanded O. Figure7showsthee,¢workspaces forthepitchandyawjointsoftheoRPYR andsRPYR wrists.The shaded areasindicate achievable angles. Thesegraphs should beinterpreted likealatitude/longitude mapoftheglobe;therightedgecanbeimagined wrapping around behind andconnecting withtheleft edge.Thetopandbottomedgescorrespond tosinglepointsatthepoles. Orthogonal RPYR Wrist 20 40 60 8 80 (deg)100 120 140 160 180 -180-160-140-120-100-80 -60-40-20020406080100120140160180 (deg)@ 2o 4o 6o so 3_00 3_20 i40 16oSkew RPYR Wrist !8-0i8C-!6C. 140-126_I00 80-60-40 20020406080!00120140160!80 (deg) Figure7.WristToolWorkspaces Fortheorthogonal wrist,whenO<45deganyangle¢canbechosen. ThusforsmallOtherangeof¢for thewristasawholeisunlimited, regardless ofthejointlimitsonroll#1.Thisisanadvantage ofPYwrist geometry overRPgeometry. However, forO>45degthecontroller mustchoose between twobranches, onecentered around ¢=0degandtheotheraround ¢=180deg.Therangeof¢available ineach branchhoversnear120degasOincreases to120deg,thenrapidlytaperstozeroatO=135deg.Values ofO>135degareinaccessible. Fortheskewwrist,therangeof¢isunlimited forO<65deg.Abovethat, therangeof¢decreases smoothly from360degto120degatO=142deg.Values ofO>142degare inaccessible. NASA/CP--2002-211506 126
Whenthe¢rangeoftheroll#1jointisadded,thetotalrangeofpossibletoolanglesforeachwristcanbe seen(Figure8).Thetopofthegraphistruncated;thevaluesreachingthetopedgeareactually unlimited. 1080 720 Range 360msRPYR []oRPYR DRPR 0 45 90 135 180 8 Figure8.ToolWorkspace Comparison ItisclearfromtheabovethateachRanger wristdesign iteration hassignificantly improved wrist workspace intoolattitude coordinates. WristDesign Details Theinternal layoutoftheRanger wristisillustrated inFigure9.Rollactuator #1isnotshown; itis structurally separate. Thepitch,yaw,roll#2,andslowtoolactuators areInlandMotorBMS-3302 brushless motors coupled toHDF-25 pancake harmonic drives(ratio120:1)fromHarmonic Drive Technologies. Position sensing isprovided byreflective opticalencoders (Agilent HEDR-8100) withdisks mounted onthemotordriveshafts. Thedisksare303stainless steelwithmachined slits,optically polished andplatedwithaluminum andsiliconmonoxide. Resolution is1920pulses perrevolution. Auxiliary position sensing isobtained using thesignals fromthethree commutation sensors (Halleffect) installed inthemotor,giving42pulsesperrevolution. Absolute position indexing isgivenbyMGC-10 10bitabsolute optical encoders fromBEIMotion Systems forpitchandyaw,andsingle-point reflective opticalposition sensors (Honeywell HLC-1395) forroll#2andtheslowtooldrive.Thefasttooldriveis direct,usinganInlandMotors RBE-01512 brushless motorinstalled inthecenterofthewrist.Fasttool position sensing isprovided byitscommutation signals. Thermistors installed inthemotorwindings allow theirtemperatures tobemonitored. Thebearings andharmonic driveshavephenolic ballseparators vacuum-impregnated withBraycote TM815Zoilandare40%filledwithBraycote TM601Egrease. Allofthewristactuators arecapable ofroughly twicetherequired torqueandtwicetherequired joint velocities, usingthepermitted levelsofcurrent andvoltage. Theforce/torque sensorisamodel45E15A-E24ES fromJR3Inc.,ratedto667N(150Ibf)inthex-andyaxes,1334N(300Ibf)inthez-axisand76.2N.m(675in-lbf)abouteachmoment axis.Wiringpasses through thecenters oftheyawandpitchactuators tominimize thevariation inwiringpathlengthasthe wristmoves. NASA/CP--2002-211506 127
Therearefouraccesscoversattachedwithwire-in-groove devices.Thematingpiecesaremachinedwith theinnerhalfandouterhalf,respectively, ofacircumferential groove.Whenassembled, a1.1mm(.045 in)diameterwireisfedintothegroovethroughatangentialhole,lockingthepiecestogether.Allopenings aresealedwithVitonTMO-rings (forstaticseals)orTeflonTMrotarysealsfromBalSeal. UESENSOR PITCHABSOLUTE ENCODER .... LASER --PITCHDRIVE ,---SLOWTOOL DRIVE ----FASTTOOL DRIVE ---YAW ABSOLUTE ENCODER YAWDRIVE INVARBEARING SLEEVE--1 OUTPUT FLANGE L.......LED_--- ROLL#2DRIVE  "_---- INVAR BEARING SLEEVE COLOR VIDEO CAMERA Figure9.Ranger WristCross-Section Positioning aidsincorporated inthewristinclude acolorvideocamera (Watec LCL-145A), withawhite LEDproviding proximity lighting. Thecamera axisisoffset7.62cm(3in)fromtheroll#2axis.Alowpowerredlaser(Quarton VLM-670-01L) isbore-sighted downtheroll#2axistoprovide avisiblereddot ontheworksite atthepointofaimforthewrist.Ranger toolsaredesigned withaxialclearance holesfor thelaserlight.Thecamera, LED,andlaserareprotected bysapphire windows. Housings throughout theRanger armsaremadeofaluminum, chosen foritslightweight, corrosion resistance, andgoodheatconduction characteristics. However, thethin-wall ballbearings usedtosupport thejointsemploy steelracesforhighstrength andsurface hardness. Theresulting mismatch inthermal expansion coefficients meansthatovertherequired temperature range,thereisariskofbearings seizing (atthecoldend)orspinning intheirhousings (atthehotend).Thisproblem wasdealtwithbyinterposing athinsleeveofInvarTMbetween thebearing andthehousing. Thesleeveisdimensioned tobealight pressfitinthealuminum atthemaximum temperature expected. Theverylowthermal coefficient of InvarTMsupplies aforceopposing thecontraction ofthehousing asthetemperature falls.Foracorrectlychosen sleevethickness, theresultisessentially constant pressure ontheouterraceofthebearing with noslippage overawidetemperature range.TheInvarTMsleeves intheyawdriveareindicated inFigure 9. NASA/CP--2002-211506 128
Tool-Exchange Mechanism Design Details Toolsareattached toIEEMsstoredon"toolposts,"whichareboltedtoconvenient surfaces withinthe manipulator's reach.Thetoolexchange sequence isillustrated inFigure10. i////_--_ __ Blocking State i:IEEM LockedtoTool Post S EM i°g IEEM flanges States3,4:Manipulator Rotates 60deg inRollState 5:Manipulator and IEEM Disengage Tool Post Figure10.ToolExchange Sequence Therearefivestatesofthemechanism. InState1(toolstoredonpost)aslotted ringretains the mushroom-shaped endofthetoolpost.Twoball-locks prevent rotation oftheslotted ring.Asthe manipulator approaches theIEEM(State2),threeteethontheoutputflangeengage notches inthe slotted ring,simultaneously depressing plungers whichrelease theballlocks.Theringisnowfreeto rotatewithrespect tothetoolpost,butisrotationally lockedtothemanipulator. Astilemanipulator begins torotateaboutthewristroll#2axis(State3),threebayonet-type flanges engage corresponding flanges ontheIEEM,locking themanipulator axiallytotheIEEM.Attheendof60degofrotation (State4),the mushroom endofthetoolpostisaligned withalargeslotinthering,andisfreetodisengage. Asthe manipulator/IEEM translates awayfromthetoolpost(State5),aliponthetoolpostrotates ablocking latchintheIEEM,preventing back-rotation oftheslottedringuntilthetoolpostisre-engaged toreverse thesequence andstorethetoolonceagain.Aspring-plunger detentprevents theblocking latchfrom vibrating outofposition whilethetoolisinuse.Thisapproach ensures asecurehandoff; atnopointisthe tooldetached fromboththetoolpostandmanipulator. Thetoolislockedtobothforasignificant overlap phasebetween States3and4. Thematingsurfaces ofthemanipulator outputflangeandtheIEEM(Figures 1and2)resemble aprobe anddrogue mechanism, whichcantolerate significant initialmisalignment. Theinterior oftheoutput flangeisconical andthecentral extension oftheIEEMiscylindrical. Astheyarepushed together they self-center, reducing misalignment toasmallvalue.Approximately 1cm(0.4in)lateraland5degangular misalignment isacceptable atinitialcontact. Thetooldrivesadjustthemselves tomeshrotationally atthe sametime.Thefasttooldriveinthemanipulator andtheslowtooldriveinthetool(ifpresent) are backdriveable toallowthisadjustment. Tosuccessfully self-center, themanipulator should beina compliant controlmode.Otherwise, verycarefulinputsfromthehumanoperator arerequired. NASA/CP--2002-211506 129
Summary A"skew"roll-pitch-yaw-roll wristgeometry wasdiscussed. Combined withcarefulpackaging tomaximize jointlimitsandminimize bulk,thisallowed theRanger wristtomeetallofitsrequirements andsignificantly outperform previous designs. Theangular workspace hasthefollowing properties: •0rangeisunlimited for_)<65deg;itdeclines from936degat0-65degto689degat e=142deg •8rangeis0to142deg •_rangeisunlimited •Allsingularities canbeavoided Theresultisastrongandrelatively compact roboticwristwhichshould rarelyfailtotrackcommanded trajectories. Acompact 5-state tool-exchange mechanism wasalsodeveloped, meeting requirements of passive actuation, securetooltransfer, tolerance tomisalignment, andarbitrary toolsize. Acknowledgements TheauthorwouldliketothankDavidAkin(Principal Investigator fortheRanger project), DavidLavery (Program Executive), andGardell Gefke(Project Manager) fortheirenthusiasm andsupport. References 1.Smith,D.B.S.,Howard, R.D.,etal.,"Space Applications ofAutomation, Robotics, andMachine Intelligence Systems (ARAMIS)," finalreportofNASAcontract NAS8-34381 (Phase I),1982. 2.Sullivan, B.,"Technical AndEconomic Feasibility OfTelerobotic On-Orbit Satellite Servicing," Ph.D. Dissertation, Aerospace Engineering Dept.,University ofMaryland, 2002. 3.Akin,D.L.,Lane,J.C.,Roberts, B.J.,Weisman, S.R.,"Robotic Capabilities forComplex Space Operations," AIAA-2001-4538, AIAASpace2001Conference, Albuquerque, NM,Aug2001. 4.Cohen, R.,Akin,D.L.,"Development ofanInterchangeable EndEffector Mechanism fortheRanger Telerobotic Vehicle," 28thAerospace Mechanisms Symposium, Cleveland, OH,May1994. 5.Howard, R.D.,Akin,D.L.,"Manipulator Design andDevelopment fortheRanger Satellite Servicing Vehicle" 26thAerospace Mechanisms Symposium, Greenbelt, MD,May1992. 6."Safety PolicyandRequirements forPayloads usingtheSpaceTransportation System," NSTS 1700.7b, SpaceShuttle Program, May1996. 7."Computer Control ofHazardous Payloads," MA2-97-083, SpaceShuttle Program Integration, 1997. 8.Roderick, S.,Churchill, P.,Gefke,G.,Akin,D.,"Design andCertification ofaTotalComputer-Based Hazard Control System foraSpace Shuttle Payload," AIAA-2000-5078, AIAASpace 2000 Conference, LongBeach, CA,September 2000. 9."Mechanical Systems Safety," MA2-00-057, SpaceShuttle Program Integration, 2000. 10.Carignan, C.R.,Howard, R.D.,"APartitioned Redundancy Management Scheme foranEight-Joint Revolute Manipulator," Journal ofRobotic Systems, vol.17,series9,January 2000. 11."Extravehicular Activity Hardware Generic Design Requirements Document," JSC-26626A, 1995. 12.Paul,R.,"RobotManipulators: Mathematics, Programming, andControl," MITPress,1981. NASA/C P--2002-211506 130