Haptics Device Falleaf

8/12/2019 Haptics Device Falleaf

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Reporter: DoanHiep Reference: REP15.04

Date: 6/13/2006 Page: 1/39

Reportno15.04Destination: KangHeeJun,DoanHiep

Topic:

HapticsDeviceBasicConceptsMICROSOFTWORD

Summary:Thisreportreviewsthebasicconceptsofhapticdevicesandshowthemethodologyinmy

research.15.02:AddHistoryofHapticDevices15.03:Thefivesenses+DirectInteractionviaahapticinterface15.04:Previousworks

1. Hapticdevices

1.1. HistoryofHumanMachineInterface(HMI)

Theworldsfirstreallogicmachine,inthesensethatitcouldactuallybeusedtosolveformallogicproblems(asopposedtothosedescribedinRamonLullsArsMagna,whichtendedtocreatemoreproblemsthantheysolved),wasinventedin1777bytheBritishscientistandstatesmanCharlesStanhope(thirdEarlofStanhope).

Inthe1870s,twoinventorsElishaGrayandAlexanderGrahamBellbothindependentlydesigneddevicesthatcouldtransmitspeechelectrically(thetelephone).

ThecathoderaytubeorCRT,inventedbyKarlFerdinandBraun,isthedisplaydevicethatwastraditionallyusedinmostcomputerdisplays,videomonitors,televisions,radardisplaysandoscilloscopes.TheCRTdevelopedfromPhiloFarnsworthsworkwasusedinalltelevisionsetsuntilthelate20thcenturyandtheadventofplasmascreens,LCDTVs,DLP,OLEDdisplays,andothertechnologies.AsaresultofCRTtechnology,televisioncontinuestobereferredtoasTheTube wellintothe21stcentury,evenwhenreferringtononCRTsets[iv].

Inparallel,3engineersofBellslabinventedthetransistorsin1947andreceivedNobleprizein1956.Fewyearslater,thefirstpopularcomputer(Apple)appears.Internetstartedintheendof1980s.

Inroboticsandteleoperation,thefirstMasterSlavemanipulatorsystemwascreatedforthenecessaryofNuclearIndustryin1940byGoertz,anditsimplementwasusedin1956.In1960,theItalianproducedunevolutionofthismodel,theMascot.

Theevolutioninthisdomain,playedacentraltechniquefortheparalleldevelopmentofthetwootherbranches:ComputerGraphicsandHumanMachine

Interface[iii].TheinteractiveInfography(ComputerGraphics)wasbornin1960withSensoramaSimulator(ExperienceTheater)ofMortonHeilig,thentheSketchpadandHMDofSutherland(1961),thenthefirstmouseofDouglasEngelbrtin1966.Intheearlyof1970s,withstandardizationandcomercializationofinterfaces(programs,materialsanddrivers)andwiththefoundationofconferenceSIGGRAPH(1974),Computer


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Graphicsbecomesindependentfield.HMIthenwentonanotherbranchwithWIMP[15].


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Time R&D Industrial Applications Technical Supports Influences

1920

Concepts of robot fromdrama

1940 Manipulators

1950Intelligent Robot

Loop memory

1960

Robot controlled bycomputers

ResearchRobot in industry

Applied at NASA and NAVY

Transistor Computer

Microprocessors

1970

AI Robotics

Boom of roboticst

Development of uP

Disavantages of

Economy

1980

Hazardous Robotics

Industrial Robots and otherapplications

Digital Technique

Optical Technique

Necessity ofAutomation

1990

Robot in production

Logic control

AI Robotics

Unemploymentbecause of robotics

2000Humanoid Robotics

Development of Mechanics


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1.2. Historyofkinethetichapticsinterface

IrepresentheresomepicturesofHapticsDeviceswhicharecreatedintermoftime

1.2.1. Palmhaptics

FirstelectricalmanipulatorofGoertzin1940s

MagLevofCarnegieMellonUniversity(1991)

SpidarofTokyoInstituteofTechnology(1991)


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PDDMoflaboratoryATR(1993)

LinearandPlanarhapticinterface(1994)

ExcaliburofWashingtonUniversity(1995)


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Mousehapticsbasedonpantograph(1997)

HapticMasterofFCSRobotics(1997)

VirtuoseofHaption(1999)109,000$


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3dofJoystickofPERCRO(2000)

1.2.2. Fingerhaptics:

ThisisthePhanTOMhaptics.PhanTOMusesthecounterbalancestomakenongravityhaptics,andtheyusePWMcontrolforDCmotorsintheircontrollers.Theirpricesfor6DOFsystemlikethisisabout78,000USD.(from1994,byThomasMassie,

student

of

Dr.

Kenneth

Salisbury

MIT)


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HapticPen,UniversityofColorado(from1996)

ThePencat/ProaproductderivedfromthePantograph(1998)

CommercializedbyHaptechInc.NowImmersionCanadaInc.


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HapticDesktop

Haptic

Pen

of

PERCRO

(from

1999)

DoublePantographStytetofUniversityofBritishColumbia(2000)


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3dofDigihapticofLIFL(2003)

1.2.4. Modularhaptics

ACROEICAhaptics(from1978,currentdesignfrom1999)

10,000Euro

for

1dof

to

30,000

Euro

for

6dof


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vBowofStandfordUniversity(2000)

HapticBlackBoxwith16tupesofUNIPI(2003)

InterfacetactilokinthtiqueofLSC

(LaboratoiredesSystmesComplexes2004)


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1.3. Thefivesenses

Phenomena Sensors Values

Audition Acouticwave Tympans/cochle 25Hz15KHz

0120dBVision Electromagnetic

waveRetina 380nm780nm

3.87.9105bps[vi]

Touch Mechanics Skinreceiver 0500Hz

0.04N100N

Taste Chemics x x

Smell Chemics x x

Referredto[5]and[vi]

1.4. DirectInteractionviaaHapticInterface

Thispartisquitecomplex,butitisaveryimportantpart.However,wecangetaverysimpleideafromthispartthatWhydontwestartatthebeginning,andwhydontweletanobjectbewhatitis?

1.4.1. IntroductiontoCausity

Theoricalproblem:Mechanically,anobjectorhumanuserproduceandreceiveforcesandpositionsinstantlyandcontinuously.Butthesignalflowbetweenhumanuserandhapticinterfaces,andsimulatedobject,andobjectsarequantitiveandinseries.Itistheunnaturalexchangementtotheoriginalduality.

Techniqueproblem:Theinfluencesofreduced(orlost)signalswillbediscussedin1.4.3.Here,weconcentratetothecausualproblem.Thedelayonthepropagationof

signals.Thesignalsmustbecapturedbythesensors,encoded,transmitted,discretized,calculatedAllmakethedelays.Theobjectthenappearsdifferrentlyfromitsmetaphorandthismetaphorwillalsobedifferentfromitssimulatedobject.Generally,thedesignofsimulatedobjecthavetotakeintoaccounttheeffectsintroducedbytheretards.

1.4.2. IntrodutiontoaMorphologyinUsersSpace

Theoricalproblem:Theusernolongermanipulatestheobjecthimself,butviaamorphologicalhaptics,whichisanassembledarticulatedmechanism.Theeffortsof

researchinginthisdomainistorazeoutthishaptics,butforgotanobjectisanobjectitself(focusonthesurface,thetexture,).Ofcourse,itispossibletotryproducingamorphologyandvirtualobjectwithmaximumcontrolledpointsgobetweeninordertohelptheuserfeelsasidenticallyastouchingdirectlytotheobject.However,thismethodbecomeslimitedbecauseoftheprecisionofthemechanismandtheactuators/sensors,


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thenumberofexpectedcontrolledpointsIftheobjectischanged,themorphologyhastobechanged.Thesecondapproachistolettheobjectbeasitpresentsandmakeamorphologytool.Theadvantageofthissolutionisthatthetoolremainsmodular(eventheobjectchanges,wecanusethesametooltomanipulateit).Itisrealistic(metaphorof

theinstrumentalinteractions)anditallowstomastermoreproperlytherelationshipbetweenthekinematic/dynamicmorphologyandsignals

Techniqueproblem:Themorphologicaltoolposescertainproblemsrelatedtocontrolthebehaviorofthemechanism,whicharethemodularityandthenumberofdegreesoffreedom.However,thisproblemgetsbacktothecausityproblemabove,andthereareonlytwoapproachremains:one,wesayautomaticsapproach,whichtrytosolvethecausialproblemintermofreducingtheeffects/contraintsoftimedelaytoapproachanidealmetaphor;another,wesayphysicallybasedapproach,whichstudythemetaphorandconsiderthecausityistheensensial/originaloftheobjectandwetrytodescribethe

objectasitis.

1.4.3. Introductiontoformalismintherepresentationofthevirtualobject

Theoricalproblem:Arealobjectisacompactuniqueandunseparated,thesensorymodalityisonlytheinterpretationrelatedtohumanfaculties.Wheneverwemodelanobject,thatisweusespecificoutputsfromsensorstodescribesomespecificbehaviorsoftheobject,suchas:dynamics,form,andphysical,geometricalcharacteristics.However,tocaptureandrepresentanybehaviorofanyobjectnaturallyisnotlike

simple.Techniqueproblem:Therearemanyformalisms,butwewillthinkaboutthemy

methodologylater.Mymethodologyisverysimplethatweusethebasiccomponentsofidealmechanism(metaphor)whicharemassesandspringsanddampers,andobservetheseparticularphysicalmodelstogeneratesimultaneouslyvisionfeedback(geometrics),soundfeedback,andforcefeedback.

Ihaveexperiences,workingontheCORDISANIMAtool,whichistheonlytoolIknowtomakethemetaphorasdescribedabove.

1.5. Somereferencesabouthaptics

Teleoperationhaslongpursuedthegoalofremotemanipulation,promisinguserstheabilitytointeractnaturallywithenvironmentsthatarenormallybeyondhumanreach.Thefirstsuchsystemsweredevelopedinthelate1940stoletanoperatorhandleradioactivematerialsfrombehindashieldedwall[1].Theseearlymasterandslaverobotswereconnectedmechanicallyandbehavedasasingleextendedtool.Theusercouldeasilyfeelinteractionforcesfromtheremoteenvironmentastheyweretransmitteddirectlythroughthemechanism.Theapplicabilityofsuchsystemswasgreatlyincreasedbyreplacingtheirsimplemechanicalconnectionwithanelectriccontrolsystem[2].Atpresent,humansuseteleroboticstoexplorethedeepsea,assembleequipmentinspace,andperformminimallyinvasivesurgery;unfortunately,thesemodernsystemsallstruggletoprovidetheuserwithnaturalfeelingfeedback.


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Anidealteleoperatorwouldmakeremoteinteractionsfeellikedirectmanipulation,portrayingthedynamicsofthedistantenvironmentwithoutdistortingtheusersmotionsorhapticperceptions.(*)[3](2005)

In[4],SittiwhosworkedwithNanomanipulatorconcludedthattheforcefeedback

canhavemucheffectsthananyothersensoryfeedback.(2003)

In[5],Burdeashowsthatmanshandcanfeelthebandwidthofvirtualforcefeedbackfromatleast5KHzto10KHz.Therefore,oneofouraimisalsotogetthebandwidthofthesystemtobe5to10KHz.(1996)

However,in[6],[15],aquitenewconceptofhapticshasbeenresearchedherewhichcallsInteractiveMultisensoryFeedback.Argumentatively,anoldwomantremblesuncontrolablybutshestillcanusethebamboosticks,knifeandallthehouseholdstuffs.Incase,ayoungmancanuseaknifetocutanapplesskinwithhisnormalarm,socan

theoldwoman.Wecanimaginethattheoldwomansarmdoesnottremble,buttheknifevibrates,withhernormalarm,shecancontroltheknifeornot?(2003)

Thisisaverybigquestiontoresearcherswhoworkonhapticsfield.

Getbacktothe(*)paragraphabove,weshouldaskaquestionthatwhatanidealteleoperatorshouldbe?Itshouldhavetherealinteractionfeedbackfromtherealremoteenvironment,notthebestcontrolsysteminsenseofrobustorstability.

[16](1980)isaveryimportantpaperaboutdelayedsystem.

Itiswellknownthatthetimevaryinglinearsystemisnotalwaysstable(unstable)

evenif

the

frozen

time

system

is

stable

(unstable),thatis,thestabilitypropertiesofthe

timevaryingsystemcannotbepredictedfromtheeigenvaluesofthecharacteristicequationofthefrozentimesystem.

Inthispaperthestabilityconditionsforafirstordersystemwithtimeorstatevariabletimedelaywereinvestigatedandthepropositionthatthetimevarying

systemisnotalwaysstable(unstable)evenifthefrozentimesystemisstable

(unstable)wasverifiedforthesystemwithvariabletimedelay.Afurtherproblemwillbetoinvestigatetheclassofthesystemwithtimevariabletimedelaywhosestabilitypropertycanbepredictedbythatofthefrozentimesystem.

[17],[18](1997,1998) areaconferenceandajournalpublishedbyOboeandFiorini.Theyshowedanewtechniquetoestimatetheconnectiondelayofinternet,saysphaseplot,andtheproblemsofdelayarecomingfrom:

Throughput:anapplicationmayfaceacongestednetworkandnotabletoexchangedataconsistently.

Delay:itsupperbounddependsonthenetworktraffic.

Delayjitter:networkloadmayinducelargedelayvariationandpacketscrambling.

Packetlosses:routinghostsmaydiscardpacketsthatoverflowtheinputbuffers.Withphaseplot,hecouldestimatea10,000kmlongconnectionwouldhaveabout

320msretards(notethatthisisinternettechniquesin19961998).In150kmdistance,

thedelaysconcentratetofasterthan10mspoints.


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Intheirpaper,thereweremanyanalysisaboutothermethods,andIagreedwiththem.However,Ileavemydiscussionintothenextpart.

In[13](2001),the3authorsshowedaveryinterestingconclusionthatSincethevelocityisnotmeasurable,whichisoftenthecaseforindustrialrobots.

Impedancecontrolisarobotforcecontroltechniqueaimedatcontrollingtherelationbetweenpositionandforce,ratherthancontrollingeitherofthesevariablesalone.Thistechniqueisoftenusedtodealwithgeometricuncertainty,i.e.,whentheexactlocationoftheenvironmentisunknown.

Sinceindustrialrobotsareoftenequippedwithpositionsensorsonly,thevelocityhadtobereconstructed.Afullorderobserverwasusedtoestimatethevelocity,andthemodeloftherobotjointneededfortheobserverdynamicswasobtainedbysystemidentification.

TheapproachtakenwasbasedonresultsonobserverbasedSPRfeedbackFJohanssonandRobertsson,2001.ThedesignincludedthesolutionofaRiccatiequation,andthestiffnessanddampingintheimpedancerelationweremodifiedbythechoiceofweightsinthedesignmatrix.StabilitywasprovenbyamodifiedPopovcriterion.

In[13],heusebothmathematicalandpracticalapproachtogetthisresult,andthesameresultswasachievedin[15]bySylvainwithhisargumentthatImpedancemodeincontrolhavesomemoreeffectsthanAdmittancemodeintelerobotics,andhapticssystems.(seeAppendixAforImpedanceandAdmittancemode).


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2. Previousworks

Followingtheresearchesonthisfield,Ihavechosensomereferencestoexplainaboutthemainideabouthapticssystems.Wehaveknownabovesomehapticdevices,butwhentheycombineandusethehapticswiththeirremoteenvironment,whatdid

theydo?Andhowdidtheydo?

Thereferencesare[7](2004),[8](1989),[9],[10](2002),

2.1. TransparencyandStabilityofBilateralKinestheticTeleoperationwith

TimeDelayedCommunication

Thisjournal[7]showsanstrateythatsimulatanenouslystabilizesbilateralkinestheticteleoperationandimprovestransparencyfortypicalcontactsituationsofthe

teleoperator.Thestrategyproposedhereisbasedonthreemajortechniques:

(i) twoportlosslesscommunicationlinetheory,

(ii) properlydesignedteleoperatortransferfunctionsbyuseoflineimpedanceadaptationfilters,

(iii) andswitchingofadaptationfiltersforsmoothoperationincaseofvaryingcontactsituations.

Forpurposesofillustrationwewillconsiderasanexampletheexperimental

bilateralkinestheticteleoperationsystemdepictedinFigure1.Itcomprisesa1DoFpaddleontheoperatorandteleoperatorsiteforkinestheticinteractionbetweena(HumanOperator)HOandtheoperatordevice,andbetweenateleoperatorandtheremoteenvironment,respectively.

Twobasicsituationsmayoccur:Incaseoffreemotion,i.e.thenocontact(NC)state,arathersmallforcesignalisfedbackfromtheteleoperatortotheoperatorsite,whichcorrespondstoagainfactorbetweenpositionandforceofnearlyzero.SincetheHOwillreceiveonlylittleinformationaboutthedriveforcesortheenergystoredintheteleoperatordevice,operationmayeasilyresultindangeroussituations.Ontheotherhand,incaseofenvironmentalcontact(EC)oftheteleoperator,smallestpositionvariationswillproducesubstantialchangesinthefedbackforce,dependingobviouslyontheenvironmentalproperties.Thismeanshighgainvaluesbetweenpositionandforcewithatendencytodestabilizetheclosedloopkinestheticteleoperationsystem.


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ImplementTechnique:Inhisexeperiments,heusedthePIcontrollerontheoperatorsideassimplyas

following:

, , ,( ) ( )des

d h p h h h d h hM k M M k = + (**)

AndheusethePDcontrolleronteleoperatorsideasfollowing:

( ) ( )desd d e p e eM k k = +

(**)IdontknowwhyheconsiderthisisanPDcontroller(hedidntmentionaboutthecontroller,butheusek_d).Butthisisforcecontrol,andthevelocityistheintegrationofaccelerationanditshouldbePIforcecontrol!!!???

Afterthat,tohavemoreaccuracy,heconsideredthehapticshavestiffnesspaddlek_n.Andhecontinuedtofindthesuitablecontrollerforthissystembyfindingk_pand

k_d.

Becauseofthedifferenciesbetweenthetwocontactmode(NoContactandEnvironmentContact),heusedswitchingstrategytoevaluatethecontrollers.Idonotfocusonthecontrolstrategy,becauseatthistimeIdonotworkoncontroller,atthistime,Iwouldliketoexpresswhatisthehaptics,andhowfarwecangowiththehaptics.

Discussion:Letsthinkabouthisproblem.WehaveatorqueontheoperatorM_h,andwealso

havethedisplacementphi_h,andheconsiderinertialofHSIiszero!!!.Iwilldiscussmoreinfollowingpapers,andIwilltrytoexplainwhytheywantthemassorinertialofthehapticsbecomeszero.

Becausethemassbecomeszero,thinkaboutthiscase.Completely,inNCmode,everythingbecomeszero,noforce,nomass,averylightgravitywasnotconsiderable.

ButinECmode,whenyouputsomethingonthetable,evenitisacup(100g),acomputer(10kg),oracarontheroad(200kg)andyoupushonit.Whatwillyougetfromforcefeedback?Wewillhavethesamevalue,thatswhytheycansetupsuchbig

valueastheywantinECmode.Thisisonewayofthinkingaboutthehaptics,becauseofthekinethetics,andthe

differentgainintwomodes(NCandEC),wecanuseswitchingstrategytohavea

goodcontroller,andconsiderthereisnohapticsmass.


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Hisresultswithnodelay.ThisisonlytheeffectofPDandPIcontroller.

2x50msdelay

Theunaccuracyforpositionisaround1cmandforforceisfrom510Nto20N

2.2. BilateralControlofTeleoperatorswithTimeDelay

Thisisthesummaryof[8](1989),whereSPONGusedthemechanics/electronicsanalogy[11](1983)toanalysethetwoportsystem.


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Thispaperhasintroducedacontrollawforcontrollingateleoperatorwithtimedelay.Theteleoperationsystemwasdevidedintofiveblocks:theoperator,master,communicationblock,slaveandenvironment.Byusingamechanical/electricalanalogy

itwasshownthattheinstabilitywhichoccursinbilateralteleoperationinthepresenceofthetimedelayisduetoanonpassivecommunicationblock.

Byactivecontrolwehaveachievedacommunicationblockwhichmimicsalosslesstransmissionlineandisthereforeguaranteedtobeapassiveelementindependentof


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timedelay.Thus,stabilityfortheteleoperatorhasbeenachievedwithoutrestrictingthebandwidthofsignals.

Discussion:Thefactthat,usingelectronics/mechanicsanalogyisjustamethodtohelpsolvingthecontrollerwithmoreease.In[12](2004)OndrejtrytouseBondGraph(see[ii]formoreinformationaboutBondGraphandPhysicallyBasedModelling)buthecouldnotarchievethegoal.Finally,hepublishedthispaperwithoutmentioningaboutBondGraph,andhisworkhadmanyunreasonableresults.

Itsimportant

to

note

that

all

passive

systems

will

be

automatically

stable.

ThisisthemostimportantthingfromSpong1989.

Thispaper[8]canalsoexplainfortherecentworksofHanaford[9],[10](2002)whenheusePassivityobserver(PO)fortimedomainPassivitycontrol(PC).

2.3. TimeDomainPasivityControlofHapticInterfaces

Inthesepapers,Hanafordprovedthestabilitycanbeachievedasusingpassivityobserverandpassivitycontrol,andheshowedtheproceduresindetailsofPOandPC.

However,fromSpongsworktoHanafords,theresultsarethesystemwillbestablebutcannotbefeltbyuserinenvironmentalcontact(EC)mode.Theresultsareshowninfollowings:


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Discussion:WhatisPC?

Thefactthat,PCissimplyanaddeddamper,andpassivitymeansdampeverythingandtheirresearchescanbecalledUnconditionalStabilization.WhyIsayso?

Becausetheessensialequationiscomingfrom:

1 2f f v= +

Thatis,youhaveadamper,anduseidenticalv_1andv_2astheinputs,thenfindf_1andf_2.However,itsunnaturalequation.Theconditionwhichisusedtofindf_1

andf_2aretheenergyflowintheport.


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Justthinkaboutthenaturaleffectsofadamper,whenwehavetheforceinputs,sayf_1andf_2,therelativepositionofthetwoendsofthedamperwillchange,andthatisvelocityoutput.Thenifthetwoendsofthedampermove,itwillgeneratethesameforceatthetwoends.Allwhathedidwasfindingsuitabledamperateachpointoftime,

sothattheportwillbecomespassive.However,thinkaboutifweuseverybigdampertoeverysystem,allthesystems

willbeautomaticallystablewithoutanycondition.So,wemaysay,thisapproachofpassivitycontrolisUNCONDITIONALSTABILITY

Noonewantswhenhecontactstoanobject,hefeelsnoforce,andinnocontactmode,hefeelstheforce.

Thisyear2006,Hanafordandhisstudentscontinuepublished[14]for6dofhapticsystem,andtheresultsarestillthesame.Hewanttoshow,inEC,forceswillbecome

zero!!!??

2.4. InducedMasterMotioninForceReflectingTeleoperation

IhavereadaboutNiemeyersLABpublications,andbeinterestedintheirresearches.Inthisreport,Idonothaveenoughtimetoexplainabouttheirworks,andthefactthattheyhaveworkedonmanyproblemsofhapticsthatatthistime,Icannotexplainindetailsaboutall.

Inthisreport,Ijustreviewwhattheyhave,andwhattheyaredoing.

In1991[21],Niemeyertriedtoovercomethelimitationofknowntimedelaybytransformingthecommunicationchannelintoalosslesspassiveconnection,whichuseswavevariablestorepresentvelocitiesandforcesexchangedbetweenthemasterandslave.


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Atthistime,Niemeyerdothesameasotherresearchthatheunderstandthesystemcanbecontrolledwithpassivity,thatisthesystembecomesstable.

In2003[20],aninterestingproceedingoncharacterizingthehumanwristshowedthatthehumanwristgraspingastyluscanbewellmodeledasasecondorderlinear

system.StiffnessandDampingwerefoundtoincreasealmostlinearlywithstylusgripforce,thoughintersubjectvariabilityfortheparameterswassignificant.

In2005,hepublishedmanypaperswithhisspecialtool(hedonottellabouthistoolindetails)tomodelthesystemwithmass,spring,damperandCoulombfriction.Hisapproachissoclosetomine.However,skimmingaroundhispapers,oneisaboutmodelingthesystem[3],the[22]heconcludedthedimensionlessformulationofthemodel(dynamicequationsofmassconnectedwithspring,dampersandCoulombfriction)allowedasimplepassivityanalysisofthehapticinterface.Thatiswecaneasilyanalysethepasivitywiththistypeofmodel.

Averyimportantnotein[23],heexplainedbouttheeffectsofCoulombfriction,anditisveryimportantinthemodels.

ThoseworksbasedonCancelingInducedMaster![24].Hisresultsaresoexciting,however,IdontknowitisgoodornotwithMasterCancelation.HisresultsintheabovefiguresayCancellationisgood.Butletsthink,doyouwantyourtooltobedisappreared?

Imreadingcarefullyabouthisworksandthankstohim,withastronglab,hegavemanyinterestingresultsforexampletheCoulombfrictioneffects,thestabilityanalysisandpasivity

Ishowheresomefiguresoftheirworks,perhapsyouneedtohavesomeexplanations:


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Iwillhavesomecommentsabouttheirhapticsstructure.Letsthinkabouttheinducedmaster.Thefact,inducedmasterisamassandwecancheckthesefollowingequations:

Atthemasterport,F_fandx_m,andtheslaveportF_tandx_c.Inourapplication,

theremoteworldislargerthanhapticsworld,whichisnormallyweusethehapticstocontrolaremotebigrobot,nottothenanoworld.Therefore,muyshouldbebig,andlamdashouldbesmall.

Howtochoosemuyandlamdaisaninterestingproblem.

ImplementingasimplepositionforcecontrollerwithoutmodifyingGf(s)andGs(s)requiresselecting andltoavoidcontactinstability.Theforwardpositionscale isusuallychosentoequatetheworkspacevolumesofmasterandslaveortoprovidemotionscalingimportanttothetask.Theforcereflectionratiolisthenincreasedfromzerountilcontactinstabilityarises.Standardteleroboticsystemscontrolledinthismannersetltovaluesmuchlessthanunity,attenuatingallforcefeedbacksignalsequivalently[25](1993)andinmanyotherpapers.

The[25]solveverycomplexmathematicalfunctionsthatIdonotdaretoreadallofthem.Butletsthink:

F_fandx_mistheforceandpositionofamass,andF_tandx_cistheforceandpositionofaspringconnectedwiththemass.

1

t c c

f c m

f c m

F K x

F K x

F K x

=

=

=

howstrongdoyouwanttofeelfromthespring?


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3. Whatarewegoingtodo?

3.1. Introductiontodualportmechanisms

3.2. MassesandLinks


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3.4. Pushandleave(Impulseresponse)

3.4.1. m1=10m2=10


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%Parameters

k = 100

m1 = 10

m2 = 100

F = 1

Throughtoutthisexample,whatdoyousee?

First,understandingaboutthesystem?Whatdoyouseefrommatlabsimulink?Whatdoyoufeelaboutthehapticsyouhavewithmatlabsimulink?

Second,mathematically,thetwomodelsarethesame.

Third,parallelcomputingmayhelpustocomputeasocomplexsystemwithmassesandlinks

3.7. WhatdoIthinkaboutoursystem?


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3.8. Howtocompute?


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4. Reference

[1]GOERTZ,R.C.,1952.Fundamentalsofgeneralpurposeremotemanipulators.Nucleonics,10(11)Nov.,pp.36.45.

[2]GOERTZR.C.,1954..Electronicallycontrolledmanipulator.Nucleonics,12(11)Nov.,pp.46.47.

[3]KATHERINEJ.KUCHENBECKERandGUNTERNIEMEYERInducedMasterMotion

inForceReflectingTeleoperation.ICRA2005.

[4]METINSITTI,TeleoperatedandAutomaticNanomanipulationSystemsusingAtomicForceMicroscopeProbes,inProceedingofthe42ndIEEE,ConferenceonDecisionandControl(IEEE,ed.),Maui,HawaiiUSA,pp.2118 2123,122003.

[5]G.BURDEA,Forceandtouchfeedbackforvirtualreality,JohnWiley&Sonsinc.,

1996.[6]CLAUDECADOZ,ANNIELUCIANI,JEANLOUPFLORENS,NICOLASCASTAGNEACROEICAArtisticCreationandComputerInteractiveMultisensorySimulationForceFeedbackGestureTransducers.Proceedingsofthe2003ConferenceonNewInterfacesforMusicalExpression(NIME03),Montreal,Canada

[7]HUBERTBAIERandGNTHERSCHMIDTTransparencyandStabilityofBilateralKinestheticTeleoperationwithTimeDelayedCommunication.JournalofIntelligentandRoboticSystems40:122,2004.2004KluwerAcademicPublishers.PrintedintheNetherlands.

[8]ROBERTJ.ANDERSONandMARKW.SPONG,BilateralControlofTeleoperatorswithTimeDelay.IEEETransactionsonAutomaticControl.Vol34,No.5,May1989.

[9] BLAKEHANAFORDandJEEHWANRYU,TimeDomainPasivityControlofHapticInterfaces,IEEETransactionsonRoboticsandAutomation,Vol18,No.1,2002.

[10]JEEHWANRYU,DONGSOOKWONandBLAKEHANAFORD,StabilityGuaranteedControl:TimeDomainPassivityApproach,IEEETransactionsonControlSystemsTechnology,Vol.12,No.6,Nov2004.

[11]R.ROSENBERGandD.KARNOP,Introduction

to

Physical

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Dynamics.NewYork:McGrawHill,1983.

[12]ONDREJJEZ,ALINAVODABESANCON,SYLVAINMARLIEREandGILDASBESANCON,DynamicModelingofaNanomanipulatorChain,2004.

[13]DANHERIKSSON,ROLFJOHANSSONandANDERSROBERTSSON,ObserverbasedImpedanceControlinRobotics,5thIFACSymposiumNonlinearControlSystemsDNOLCOS01E,StPetersburg,Russia,July2001.

[14]CARSTENPREUCHE,GERDHIRZINGER,JEEHWANRYUandBLAKE

HANAFORD,Time

Domain

Passivity

Control

for

6

Degrees

of

Freedom

Haptic

Displays,2006(CITESEER)

[15]SYLVAINMARLIERE,ConceptionetRealisationdunNouvelOutilaRealiteMixteetRetourdEffortpourToucheretCreerlesNanomondes,ThesepourobtenirlegradededocteurdelINPG,SpcialitAutomatiqueProductique,2006.


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[16]KAZUMASAHIRAIandYOSHIAKISATOH,StabilityofaSystemwithStableTimeDelay,IEEETransactionsonAutomaticControl,Vol.AC25,No.3,June1980.

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[i]www.answers.com:somedefinitions

[ii]www.cs.cmu.edu/~baraff:AnIntroductiontoPhysicallyBasedModelling

[iii]http://www.catb.org/~esr/writings/taouu/html/ch02.html:Chapter2.History:ABrief

Historyof

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Interfaces

[iv]http://en.wikipedia.org/wiki/Cathodic_ray_tube:HistoryofCathodicRayTubeandCRT

[v]http://sklabwww.pi.titech.ac.jp/~seahak/vr.html:SpidarofTokyoInstituteofTechnology

[vi]http://en.wikipedia.org/wiki/Retina:Retina


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5. AppendixA:ImpedanceandAdmitancemodeinControl

Inelectricalengineering,theadmittance(Y)istheinverseoftheimpedance(Z).TheSIunitofadmittanceisthesiemens.OliverHeavisidecoinedtheterminDecember1887.

where

Yistheadmittance,measuredinsiemens

Zistheimpedance,measuredinohms

Justasimpedanceiscomplexresistance,andtheconductanceGistheinverseG=1/RofresistanceR,admittanceisalsocomplexconductance.

Likewise,admittanceismadeupofarealpart(theconductance),andanimaginarypart(thesusceptanceB),shownbytheequation

Themagnitudeofadmittanceisgivenby:

where

Gistheconductance,measuredinsiemens

Bisthesusceptance,measuredinsiemens

Inmechanicalsystems(particularlyinthefieldofhaptics),anadmittanceisadynamicmappingfromforcetomotion.Inotherwords,anequation(orvirtualenvironment)describinganadmittancewouldhaveinputsofforceandwouldhaveoutputssuchaspositionorvelocity.So,anadmittancedevicewouldsensetheinputforceandadmit acertainamountofmotion.

Similartotheelectricalmeaningsofadmittanceandimpedance,animpedanceinthe

mechanicalsensecanbethoughtofastheinverse ofadmittance.Thatis,itisadynamicmappingfrommotiontoforce.Animpedancedevicewouldsensetheinputmotionandimpede themotionwithsomeforce.

Anexampleoftheseconceptsisavirtualspring.TheequationdescribingaspringisHookesLaw,

Iftheinputtothevirtualspringisthespringdisplacement,x,andtheoutputistheforcethatthevirtualspringapplies,F,thenthevirtualspringwouldbeclassifiedasanimpedance.Iftheinputtothevirtualspringistheforceappliedtothespring,F,andtheoutputisthespringdisplacement,x,thenthevirtualspringwouldbeclassifiedasanadmittance.


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5.1. Impedancecontrolvs.admittancecontrol

Therearetwomajorwaysinwhichahapticdevicecanbecontrolled,thesocalledimpedancecontrolandadmittancecontrolparadigms.Bothalgorithmsarediscussedbelow.

5.1.1. Impedancecontrol

Inimpedancecontrol,theparadigmis:theusermovesthedevice,andthedevicewillreactwithaforceifneeded.Thisisthebasicinteractionbetweentheuserandthecontrolloop.Viewedfromthecontrolloop,theparadigmis:displacementin forceout.

Insimulatedfreeair,theuserisfreetomovethedevice,andthemotordoesnotnot

havetodoanything.Incontrolterms:thegainfromchangesinpositiontochangesinmotorforceiszero.Thiswillholdevenifthedeviceisincontactwithahardphysicalsurface.Thereisnospecialstabilityproblemthere,sincetheobjectcanstoptheendeffectorwithoutanyspecialreactionbeingrequiredofthemotor.

Incontactwithasimulatedhardsurfacehowever,thereisastabilityproblem.Anysmallchangeinpositionwillcause averyhighriseinmotorreactionforcewhilethedeviceisincontactwiththevirtualwall.Thisimpliesaveryhighcontrolgainfrommeasureddevicepositiontomotorforce.Forstability,controlgainscannotbecomeinfinitelyhigh.Therefore,inanimpedancecontrollerthereisalimittothehardness or

stiffnessofavirtualsurfacethatcanberenderedstably.

5.1.2. Admittancecontrol

Inadmittancecontrol,theparadigmis:thedevicemeasurestheforcesthattheuserexertsonit,andreactswithmotion(acceleration,velocity,position).Viewedfromthecontrolloop,theparadigmis:forcein displacementout.


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Tosimulatefreeair,thedeviceneedstoaccelerateveryquicklyatthelightesttouch.Thismeansaveryhighcontrolgainfromforceinputtoaccelerationoutput.Averylowsimulatedmassmeansaveryhighcontrolgain.So,admittancecontrolleddeviceshaveapotentialstabilityprobleminfreeair,whenthemassneedstobelow.Thesameholdsonaphysicalhardsurface.Asmallmovementofthemachinewillgiveastrongriseincontactforefromthephysicalsurface.Itisthephysical

environmentwhichclosestheadmittancecontrolloopwithaveryhighgainfrompositiontoforcethistime,creatingcontactinstability.Onasimulatedvirtualsurfacehowever,averyhighforcewillcommandonlyaverysmallmotion.Infact, onforaninfinitelystiffsimulatedsurface,thecontrolgainfromforcetopositioniszero.

6. AppendixB:WordsExplanations

DelayjitterisonekindofjitterreferredtoinRTSP.

Itisthefluctuation/variationofendtoenddelayfromonepackettothenextpacketwithinthesamepacketstream/connection/flow.

Example:Packetsaretransmittedattheintervalof20ms.

Ifthe2ndpacketreachesafter30mswithrespecttothe1stpacketarrival.Jitter=10ms.Thisisreferringasdispersion.

Ifthe2ndpacketreachesafter10mswithrespecttothe1stpacketarrival.Jitter=+10ms.Thisisreferringasclumping.

7. AppendixC:Dualportispassiveandlosslesscommunicationline

DefinitionB.1:Annportissaidtobepassiveifandonlyifforanydependentsetofnportflows,

iv injectedintothesystem,andefforts jF appliedacrossthesystem:

0

( ) ( ) 0TF t v t dt

[ , ,..., ] ( )T n

F F F F L R= ( ) [ , ,..., ] ( )T nv t v v v L R=

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