Cellular Actuators Cellular Actuators Modularity and Variability in Muscle-inspired Actuation Jun Ueda Georgia Institute of Technology, 771 Ferst Drive, Atlanta, GA 30332 Joshua A. Schultz The University of Tulsa, 800 South Tucker Drive, Tulsa, OK 74104 H. Harry Asada Massachusetts Institute of Technology, 77 Mas- sachusetts Avenue, MA 02139 Butterworth-HeinemannisanimprintofElsevier TheBoulevard,LangfordLane,Kidlington,OxfordOX51GB,UnitedKingdom 50HampshireStreet,5thFloor,Cambridge,MA02139,UnitedStates Copyright©2017ElsevierInc.Allrightsreserved Nopartofthispublicationmaybereproducedortransmittedinanyformorbyanymeans,electronicor mechanical,includingphotocopying,recording,oranyinformationstorageandretrievalsystem,without permissioninwritingfromthepublisher.Detailsonhowtoseekpermission,furtherinformationaboutthe Publisher’spermissionspoliciesandourarrangementswithorganizationssuchastheCopyrightClearanceCenter andtheCopyrightLicensingAgency,canbefoundatourwebsite:www.elsevier.com/permissions. ThisbookandtheindividualcontributionscontainedinitareprotectedundercopyrightbythePublisher(other thanasmaybenotedherein). Notices Knowledgeandbestpracticeinthisfieldareconstantlychanging.Asnewresearchandexperiencebroadenour understanding,changesinresearchmethods,professionalpractices,ormedicaltreatmentmaybecomenecessary. Practitionersandresearchersmustalwaysrelyontheirownexperienceandknowledgeinevaluatingandusing anyinformation,methods,compounds,orexperimentsdescribedherein.Inusingsuchinformationormethods theyshouldbemindfuloftheirownsafetyandthesafetyofothers,includingpartiesforwhomtheyhavea professionalresponsibility. Tothefullestextentofthelaw,neitherthePublishernortheauthors,contributors,oreditors,assumeanyliability foranyinjuryand/ordamagetopersonsorpropertyasamatterofproductsliability,negligenceorotherwise,or fromanyuseoroperationofanymethods,products,instructions,orideascontainedinthematerialherein. LibraryofCongressCataloging-in-PublicationData AcatalogrecordforthisbookisavailablefromtheLibraryofCongress BritishLibraryCataloguing-in-PublicationData AcataloguerecordforthisbookisavailablefromtheBritishLibrary ISBN:978-0-12-803687-7 ForinformationonallButterworth-Heinemannpublications visitourwebsiteathttps://www.elsevier.com Publisher:JoeHayton AcquisitionEditor:SonniniYura EditorialProjectManager:MarianaKuhl ProductionProjectManager:MohanaNatarajan Designer:GregHarris TypesetbyVTeX List of figures Fig.I Qualitativecomparisonofactuatormaterialsandnaturalmuscle. xxvi Fig.II Molecularrepresentationandstructureofasarcomere.Imagetakenfrom [188]andusedwithpermissionunderthecreativecommonslicense. xxix Fig.III BistableON–OFFControl.©2007SAGEPublications xxxi Fig.IV BistableON–OFFcontrolofactuatormaterials.©2007SAGEPublications, modifiedandreprintedwithpermission xxxi Fig.V Communicationbetweencontrollerandcellularunits. xxxii Fig.VI Broadcastcontrolandstochasticdecisionmaking. xxxiii Fig.VII Traditionalcontrolparadigmonacellularactuator:(A)contrastedwith aparadigmthatoperatesbyrecruitment;(B)usingrecruitmenttakes advantageofthecellularstructure.(Forinterpretationofthecolorsinthis figure,thereaderisreferredtothewebversionofthisIntroduction.) xxxiv Fig.VIII Broadcastfeedback. xxxv Fig.1.1 Piezoelectricactuatormodel. 2 Fig.1.2 Piezostackactuator.CourtesyofCEDRAT,Inc. 2 Fig.1.3 BenderPiezoActuatororbimetaltypeactuator.CourtesyofPI. 3 Fig.1.4 Moonieactuator:(left)from[182]and(right)courtesyofCEDRAT,Inc. 3 Fig.1.5 Cymbalactuator[60].©1997IEEE,reprintedwithpermission 4 Fig.1.6 Thunderactuator[46].CourtesyofFaceInternationalCorporation. 4 Fig.1.7 ExtensilePZTstrainamplifier:(A)single-cellextendingPZTactuator model,(B)fabricatedthreecellPZTactuator.©2006IEEE,reprintedwith permission 5 Fig.1.8 Force–displacementcurveoftheexpandingPZTactuator.©2006IEEE, reprintedwithpermission 5 Fig.1.9 MEMS–PZTcellularactuator:(A)alargestraincontractingPZTactuator celldesign,(B)seriallystackedandconnectedPZTactuatorcellsintoa module.©2006IEEE 6 Fig.1.10 Nestedstructureforexponentialstrainamplification. 7 Fig.1.11 Amplificationprincipleofflextensionalmechanisms[182].©2010IEEE, reprintedwithpermission 8 Fig.1.12 Generalizednestingforexponentialstrainamplification.Thestrainis amplifiedbythreelayersofrhombusstrainamplificationmechanisms,with thefirstlayer,calledanactuatorlayer,consistingofthesmallestrhombi directlyattachedtotheindividualPZTstackactuators.©2010IEEE, reprintedwithpermission 10 Fig.1.13 Three-dimensionalnestingfor20%strain.©2010IEEE,reprintedwith permission 11 Fig.1.14 Schematic assembly of nested rhombus multi-layer mechanism. ©2013Springer,reprintedwithpermission 11 Fig.1.15 ActuatorcoordinatesystemofPZTstackactuator.©2010IEEE,reprinted withpermission 13 viii CellularActuators Fig.1.16 Three-dimensionalstackingofactuatorunits.©2007IEEE,reprintedwith permission 14 Fig.1.17 Idealizedanalysis.Complianceoftheamplificationmechanismisnot considered.©2010IEEE,reprintedwithpermission 15 Fig.1.18 Finallayerconnection.©2007IEEE,reprintedwithpermission 16 Fig.1.19 Reconfigurabilityofthecellularactuators.©2007IEEE,reprintedwith permission 16 Fig.1.20 ModelofPZTstackactuatorconnectedtoaspringload. 18 Fig.1.21 Embodimentofarhombusmechanism. 18 Fig.1.22 Effectofjointcomplianceonfree-loaddisplacement. 19 Fig.1.23 Effectofbeamcomplianceonblockingforce. 19 Fig.1.24 ModelofRhombusMechanismwithFlexibility. 21 Fig.1.25 SimplifiedRepresentationofLumpedParameterModel. 24 Fig.1.26 Recursiveformulaforanestedrhombusmodel. 24 Fig.1.27 Exampleamplificationmechanisms. 26 Fig.1.28 Requirementofinput–outputbidirectionality. 28 Fig.1.29 Designofarhombusmechanismforthe2ndlayer. 29 Fig.1.30 Choiceofaˆ forpositivespringconstants. 30 Fig.1.31 Prototypeactuator:6CEDRATactuatorsareusedforthefirstlayer. 31 Fig.1.32 Snapshotsoffree-loaddisplacement:Twonestedrhombusmechanisms areconnectedinseries.Eachunitgeneratesapproximately21%effective straincomparedwithitsoriginallength.©2008ASME,reprintedwith permission 31 Fig.1.33 Experimentalresult. 32 Fig.1.34 BinaryON–OFFControlExperiment. 33 Fig.1.35 Microgripper.©2012Springer,reprintedwithpermission 33 Fig.1.36 Micromanipulator.©2012Springer,reprintedwithpermission 34 Fig.1.37 (A)Workingprincipleshowingdeformedandundeformedflexuresintwo planes.(B)A5cellartificialmuscleactuatorbasedonPZT-drivenflexures. ThephysicalprototypeusestwoNECTokinPZTStacks.©2010IEEE, reprintedwithpermission 34 Fig.1.38 Fabricationofthecellularactuatorarraysand1-DOFroboticarm. 35 Fig.1.39 MotionofthePZT-driven1-DOFroboticarm. 36 Fig.1.40 Assembledend-effectornestingactuatormodule. 36 Fig.1.41 Assemblyofatweezer-stylepiezoelectricend-effector. 37 Fig.1.42 Schematicmodeloftheend-effectorstructure.©2010JSME,reprintedwith permission 38 Fig.1.43 Drawingsofthetweezer-styleend-effector.©2010JSME,reprintedwith permission 38 Fig.1.44 Fabricatedend-effector. 39 Fig.1.45 Motionoftheend-effector.Thedevelopedend-effectorhasareverseaction mechanism;thetipsclosewhentheactuatorsareenergized. 39 Fig.1.46 Displacementandforceperformance.Circlesareforward(from0to 150[V])andinverse-trianglesarebackward(from150to0[V])directions; notethat(A)showstheabsolutedisplacementofoneoftheend-points.The totaldisplacementistwiceofthismeasurement.©2012IEEE,reprinted withpermission 39 Fig.1.47 Manipulationusingthetweezer-styleroboticend-effector. 40 Listoffigures ix Fig.1.48 Three-layerrhomboidalamplificationmechanism. 41 Fig.1.49 Roboticvisionsystem.©2015SAGE,reprintedwithpermission 42 Fig.1.50 Pictorialrepresentationofthecameraorientationsystem[219].Thecamera positionerdrivenbyanantagonisticpairofcellularactuators. 43 Fig.1.51 Singledegree-of-freedommotionofthecameraorientationsystem. ©2013IEEE,reprintedwithpermission 43 Fig.1.52 Muscle-likecomplianceoftheamplificationmechanism:(Left)lumped parametermodeloftheactuator;(Right)Hill’smusclemodel[294]with contractileelement(CE)thatproducesforce,serieselement(SE),parallel element(PE),anddampingelement(DE).ltendon isthelengthofthe tendon,lmuscle isthelengthofthemuscle,andξ isthepennationangleof themuscle. 44 Fig.2.1 Anoverlysimplisticunderstandingoftheamplificationprincipleof arhomboidalstrainamplifyingmechanismthatdoesnotaccountfor deformationinthepiezoelectricmaterialandtherhomboiditself. 46 Fig.2.2 Arepresentationofatwo-portnetworkmodel.©2013IEEE,reprintedwith permission 47 Fig.2.3 Free-bodydiagramofaflexiblesegment. 52 Fig.2.4 Doublysymmetricactuatorcomposedofstraightsegments. 53 Fig.2.5 Comparisonofanactuatorwiththesameouterlayeranddifferentnumbers ofinternalsubunits. 58 Fig.2.6 Activeandinactivesubunitsrepresentedassprings. 59 Fig.2.7 Seriescombinationdisplacementratio. 61 Fig.2.8 Seriescombinationforceratio. 61 Fig.2.9 Multi-layernestedgeometrywithreuseofacompliantmechanism. ©2013IEEE,reprintedwithpermission 63 Fig.2.10 Boundsondisplacementfigureofmerit. 65 Fig.2.11 Variationinfigureofmeritwithangleandthickness.©2013IEEE,reprinted withpermission 65 Fig.2.12 Existingactuatorforwhichahigherfreedisplacementisdesired. 66 Fig.2.13 Adding an additional strain amplifying mechanism to amplify the displacementoftheactuatorinFig.2.12stillfurther. 67 Fig.2.14 Generaloctagonalrhomboidalshapeshowingthegeometricparameters. The depth into the page of the shape will be denoted b, i.e., the finalimplementationwillbemachinedfromaplateofthicknessb. ©2013IEEE 71 Fig.2.15 Mechanismcharacteristicsusedinexperiment.Parametersareasin Fig.2.14.©2013IEEE,reprintedwithpermission 74 Fig.2.16 Firstexperiment(inputfixed).©2013IEEE,reprintedwithpermission 76 Fig.2.17 Secondexperiment(outputfree).©2013IEEE,reprintedwithpermission 76 Fig.2.18 Variationinimmittanceparameters:(A)s1,(B)s2,and(C)s3withgeometry. ©2013IEEE,reprintedwithpermission 78 Fig.2.19 Singledegreeoffreedomroboticjoint.Theagonist(left)isactivatedand contracts.Theantagonist(right)behavesasapassivestiffness.Thisaffects therelationshipbetweenappliedloadandjointangle. 82 Fig.2.20 Collapsingoftwo-portnetworks.Eachsquareboxrepresentsatwo-port network,withavoltageandcurrentattheright-andleft-handports.The entirehierarchywithinthedashedlinesiscollapsedandreplacedwithits Nortoncircuit.©2013IEEE,reprintedwithpermission 85 x CellularActuators Fig.2.21 Two-portrepresentationofantagonisticpairs.Theactiveactuatorisinblack andhasallbuttheoutermostlayercollapsedandrepresentedbyitsNorton circuit.Thepassiveactuatorisingrayandiswillbereplacedbyasimple stiffness.©2013IEEE,reprintedwithpermission 86 Fig.2.22 Convergenceofthevariousstiffnessapproximationsforahypothetical many-layeredmechanismwithrandomlychosenimmittances.yk is theinput-fixedapproximationthroughlayerk,andxk istheinput-free approximation.©2013IEEE,reprintedwithpermission 92 Fig.2.23 PZTstackwithasinglelayerofamplification.©2012IEEE,reprintedwith permission 96 Fig.2.24 Parameterizationofarhomboidalmechanism.©2012IEEE,reprintedwith permission 96 Fig.2.25 PZTstackwithtwolayersofamplification.©2012IEEE,reprintedwith permission 97 Fig.2.26 Parameterspaceregionforatwo-layermechanism. 98 Fig.2.27 Atwo-layeractuatordesignthatmeetsthe8mmdisplacementspecification. Thisdesignwasrejectedinfavorofathree-layermechanismbecausethe “bow-tie”shapewasnotasgoodofauseofspaceandposedmanufacturing difficulties. 98 Fig.2.28 Customstrainamplifierforthetwo-layeractuatorthatamplifiesaseries chainof16CédratAPA50XSamplifiedpiezoelectricstacks. 98 Fig.2.29 PZTstackwiththreelayersofamplification. 100 Fig.2.30 Blockedforcevariationwithgeometry. 102 Fig.2.31 Secondlayereffectonblockedforce. 102 Fig.2.32 Hill-typemodel. 106 Fig.2.33 Explanationofincidencematrixcomponentsforalayerbasedactuator arraytopology:OutgoingconnectionsarerepresentedbyGandincoming connectionsarerepresentedbyH. 108 Fig.2.34 Examplesof(A)alayerbasedactuatorarraystructureand(B)anon-layer basedactuatorstructure.Thelayerbasedarrayhastwocellsoneachpath betweenarrayendpointswhilethenon-layerbasedarrayhasonepathwith oneandonewithtwo.Withidenticalcells,thenon-layerbasedarraywould likelygenerateinternalcompressiveforces. 108 Fig.2.35 Examplearraytopologies.©2011SAGEPublications,reprintedwith permission 109 Fig.2.36 Exampleofbuildingafingerprintfromanactuatorarraytopology. 109 Fig.2.37 Incidencematrixrepresentationofafingerprint. 110 Fig.2.38 Frontsectionautogenerationexample.©2011SAGE,reprintedwith permission 111 Fig.2.39 Autogenerationprocesstreeforgeneratingfingerprintsforarrayswith 4cells.Thethirdrowineachrepresentationshowsunallocatedcells remaining. 112 Fig.2.40 Automaticallygenerated23topologiesfor5cells.©2011SAGE,reprinted withpermission 112 Fig.2.41 Automaticallygeneratedtopologiesandcomputationaleffortfor1–9 cells. 113 Fig.2.42 Exampletransitionsbetweenidenticaltopologies. 115 Fig.2.43 Robustnessmeasure:“minimumcelllosstouncontrollability”=3. 117 Listoffigures xi Fig.2.44 Dynamicmodelingofathree-layerhierarchicalactuatorarray. 118 Fig.2.45 Forceattheendofthepiezoelectricbasedcamerapositioneractuatorarray underisometriccontraction. 118 Fig.3.1 Referencecommandgoingfrom0to3unitsactiveafterbeingputthrougha ZVshaperwitha63msdelay. 123 Fig.3.2 Vectordiagramshowingimpulsesrepresentedasphasorsinthecomplex plane.Thevectordiagramsfortwofrequenciesaresuperimposedontopof oneanother.Thelowerfrequencyisshownwiththesolidarrows,thehigher ofthetwoasthedashedarrows.ThephaseoftheimpulseA1,φ1,isshown explicitly.Tobeavibrationsuppressingcommand,bothsetsofimpulses mustsumtozerointhecomplexplane. 125 Fig.3.3 Illustrationofall-ONall-OFFcontrolforamovefrom0to4unitsON (greendenotestheONstateinboththeplotandtheillustration).(For interpretationofthereferencestocolorinthisfigurelegend,thereaderis referredtothewebversionofthissection.) 127 Fig.3.4 Close-upviewofthetwo-layercantileveredactuatorusestovalidatethe DSVSmethod. 131 Fig.3.5 Significantvibrationmodesofthecellularactuator.©2012IEEE,reprinted withpermission 132 Fig.3.6 Flowchartdepictingalgorithmtodetermineswitchingpattern.©2012IEEE, reprintedwithpermission 134 Fig.3.7 VenndiagramillustratingthevariousDiscreteSwitchingVibration SuppressionCommands. 136 Fig.3.8 Diagramofhowarbnovib2f.mfindsacommandthatmeetsthegoalyg andsuppressesthetwomodesofvibration.©2012IEEE,reprintedwith permission 138 Fig.3.9 MSDSVSexperimentalsetup.©2012IEEE,reprintedwithpermission 141 Fig.3.10 Frequencyresponseofcellularactuator.©2012IEEE,reprintedwith permission 142 Fig.3.11 Variouscommandstoposition1. 143 Fig.3.12 Variouscommandstoposition2. 143 Fig.3.13 Variouscommandstoposition3. 144 Fig.3.14 Variouscommandstoposition4. 144 Fig.3.15 Variouscommandstoposition5. 144 Fig.3.16 Variouscommandstoposition6. 145 Fig.3.17 Responsetocommandstoposition6. 145 Fig.3.18 Residualoscillation,largestFFTcomponent. 146 Fig.3.19 RMSoscillation,normalizedbymovedistance.©2012IEEE,reprinted withpermission 146 Fig.3.20 Framesfromhigh-speedvideoshowingthemotionoftheactuator: (A)actuatorbeforethecommandisapplied,(B)maximumexcursionwhen all6inputsareactivatedatonce,(C)actuatoratmaximumexcursionunder anMSDSVScommandfromposition0to6,and(D)actuatoratmaximum excursionunderAllON/AllOFFcontrolfromposition0to6. 147 xii CellularActuators Fig.3.21 Oscilloscopecaptureofthecellularactuatorreceivingasinusoidalinput. Thegreensignalisfromafunctiongenerator,theyellowisthehighvoltage signalacrossthePZTstackfromtheamplifier.Thebluecurveisthe displacementofthecellularactuator,measuredbytheOptoNCDTlaser positionsensor.Noticethatalthoughtheinputvoltageissinusoidal,the displacementisnot.(Forinterpretationofthereferencestocolorinthis figurelegend,thereaderisreferredtothewebversionofthissection.) 148 Fig.3.22 Energyconsumptionpermove.©2012IEEE,reprintedwithpermission 150 Fig.3.23 SensitivityplotforAllON/AllOFFcontrolandMSDSVS.©2012IEEE, reprintedwithpermission 151 Fig.3.24 Responsewhencommandandplantfrequencymismatched. 152 Fig.3.25 Splitshotsinkersattachedtothecellularactuatortoshifttheresonant frequencyofthefirstmode. 152 Fig.3.26 Cellularactuatorresponsewhenthenaturalfrequencyischangedbyadding masstotheactuator.©2012IEEE,reprintedwithpermission 153 Fig.3.27 Singlecell. 154 Fig.3.28 AggregateMarkovmodel. 155 Fig.3.29 ProbabilitydistributionfordifferentN. 156 Fig.3.30 Broadcast feedback for a cellular control system with distributed decision-makingunits. 157 Fig.3.31 Compensationfortheerrorbyclosed-loopcontrol. 158 Fig.3.32 Singlecellwithunilateraltransitioncontrol. 161 Fig.3.33 Stabletransitionprobabilities. 163 Fig.3.34 Simulationsnapshots:(white)ONcell,(black)OFFcell. 165 Fig.3.35 Simulationresults:stepresponse. 166 Fig.3.36 Simulationresults:sinusoidaltrajectorytracking. 167 Fig.3.37 Distributionofthecelllength.©2007IEEE,reprintedwithpermission 169 Fig.3.38 Stabletransitionprobabilities.©2007IEEE,reprintedwithpermission 170 Fig.3.39 SimulationresultsforN = 25withnon-uniformtransitionprobability. ©2007IEEE,reprintedwithpermission 170 Fig.3.40 SimulationresultsforN =25withnon-uniformcelllength.©2007IEEE, reprintedwithpermission 170 Fig.3.41 SimulationresultsforN =1000withnon-uniformcelllength,non-uniform transitionprobability,and20%ofdeadcells.©2007IEEE,reprintedwith permission 171 Fig.3.42 Input–outputcharacteristicsofhystereticmaterials.©2011ASME,Wood, L.,reprintedwithpermission 173 Fig.3.43 Coordinatedcontrolofmultitudeofcellularunits.©2011ASME,Wood, L.,reprintedwithpermission 173 Fig.3.44 HysteresisloopcontrolofSMAactuatorunit. 175 Fig.3.45 Statetransitionofhysteresisloopcontrol. 175 Fig.3.46 Mappingoftransitionprobabilityprofilesonhysteresisloop. 176 Fig.3.47 Broadcastfeedbackwithlocalizedstochasticrecruitment(BFSR)forSMA cellularactuatorarray.©2006IEEE,reprintedwithpermission 177 Fig.3.48 Centralizedbinary-schemerecruitment(CBR).©2006IEEE,reprintedwith permission 179 Fig.3.49 Binaryrecruitment.©2006IEEE,reprintedwithpermission 179 Fig.3.50 Centralizedsequentialrecruitmentofuniformsegments(CSR). 179
Description: