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Application of the repulsive‑type magnetic bearing technology based on digital control implementation for manufacturing a micro‑mass measurement balance system

著者 Hussien Mahmoud Alaa Abdel Moneim

著者別名 ホセイン マハモド, アラー アブディル モーネイ

ム journal or

publication title

博士学位論文要旨 論文内容の要旨および論文審査 結果の要旨/金沢大学大学院自然科学研究科

volume 平成19年9月

page range 16‑30

year 2007‑09‑01

URL http://hdl.handle.net/2297/26679

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AmAAABDELMONmMHUSSIENMOHAMUD 博士(工学)

博甲第841号 平成18年9月28日

課程博士(学位規則第4条第1項)

ApplicationoftheRepulsive-TypeMagneticBearinglbchnologyBasedon DigitalControllmplementationfbrManufblcturingaMicro-Mass

MeasurementBalanceSystem

.(極微小質量計測天秤へのデジタル制御反発形磁気軸受の応用に関する研究)

山田外史(自然計測応用研究センター・教授)

岩原正吉(自然科学研究科・教授),上杉喜彦(自然科学研究科・教授),

神谷好承(自然科学研究科・教授),滑川徹(自然科学研究科・助教授)

氏名 学位の種類 学位記番号 学位授与の日付 学位授与の要件 学位授与の題目

論文審査委員(主査)

論文審査委員(副主査)

学位論文要旨

Abstract

Therepulsive-typemagneticbearingtechnologyisbecomingattractivefbrmany applicationsinrecentyears,specially,fbrtllehighprecisionmstmnents・Themost importantfeatureofmagneticbearingingeneralisthecontact-丘eeoperation・Inaddition,

tllerepulsivetypespeciallyofferslnanyotlleradvantagessuchas,slnallnumberof electromagnetsandasmnplifiedschemeareneededfbrcontrol,italsohaveasoftand constantstifnesstothepassivecontrolaxis・so,tllistypeofbearingisriglltsuitedfbr lnanyapplications、Inthisthesis,tllerepulsivetypemagneticbearingbasedondigital controlilnplementationisemployedtomanufactureabalancesystemwhichcanmeasure nncrolnasses、Theproposedsystemconsistsofanaxialshaftandabalancebeam,tlleshaft islevitatedalongtlleradialdirectionbytllerepulsivefbrcesoftllelnagneticbearing sectionandalongtheaxialdirectionbyacontrolledelectromagnet・Thebeamiskeptatan eqUilibriumhorizontalpositionTheprincipleoperationdependsontransfeningtllelnass

valuetotllecurrentofacontrolledactuator・Thefimctionoftllesystelnasamass

measuringdeviceisconfirlnedbymeasunngsomesamplesandevaluatmgtllesystem lneasurelnentcharacteristicssuchassensitivity,controlcurrenthysteresisandlinearity.

1.Introduction

Itiswellknownthatelectronicsnowprovidetlle‘brams,fbrtoday,sadvancedsystems

andproducts,nncromechanicaldevicescanprovidetllesensorandactuator,tlleeycsand ears,handsandfeetwhichinterfacetotlleoutsideworld・Fordevelopmgbothelectronics andnlicrolnechanicalsystems,tllefieldofmaterialsciencehasgivenmuchofinterest、One oftlleimportanttopicsofmaterialscienceistllematerialcharacterizationwhichis perfbrlnedtospecifWllephysicalpropertiesoftllematerials・ThematerialCharacterization canbeachievedthroughsomechelnicalanalysissuchasdifferentialtllermalanalysis (DTA)andtllermogravetencanalysis(TGA).

Themassmeasurementdeviceswhichhavehighmeasunngsensitivitytodetectthelninute

changeofasa【nplemassarenecessaryfbrperfbrnmngsuchkindofmaterial characterizationanalysis・Insomeapplications,therangeofthatchangereachestlleorder of皿crogramsorevennano-grams・Theimportanttopictobeconsideredwllile lnanufacturinghighsCnsitivitymassmeasurementdevicesistllebearingmetllod、The repulsive-typemagneticbearingisanon-contactoperationmetllod,sonoproblcmanses 丘Cl、随ctionwhichusuallyaffectstllesystemsensitivity・Inaddition,itisasmgle-axis controlledsystelnsotllenumberofperipheraldeviccssuchassensorsandactuatorsare

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reducedandasaresultsilnpleandsmallsizesystemdesignispossible、Anotllerimportant featureofthattypeOfbearingisthesoftandconstantstifnesstotllepassivecontrolaxis wllichensuresgoodlevitationstabilityalongtheradialdirection[1]-[3]、so,fbrtlle applicationsoftheearlierreqUirements,therepulsive-typemagneticbearingisrightsuited fbrnlanufacturingwhatiscalled“Repulsivctypemagneticbearingnucromass

lneasurementsystem.,,

Inthistllesis,theconfigurationoftherepulsivetypemagneticbearingsectionandfbrces analysisisgivenThissectionisemployedfbrmanufacturingtlleproposedbalancesystem whichconsistsoftwomainparts,tlleaxialshaftpartandtllebalancebeampart・The completesetupoftlleproposedbalancesystemandtheoperatmgfeaturesaremcluded

Thesystemmathematicallmearizedmodeisobtamedandcontrollersfbrbothshaftand

beamareimplementedaroundaDSP、Theexperilnentalresultsfbrconfirn血gtllefUnction

oftllesystemasalnassmeasuremelltdeviceandevaluationofitScharacteristicssuchas

linearity,accuracy,andprecisionaregiven[4],[5].

2.Configurationoftlnerepulsivetypema窪neticlDearingsection

2.ISmJc"〃qハノjePMsecがo〃

Thestructureoftherepulsive-typemagneticbeamgsectionisshowninFigl(a).It consistsoftwounits,eachunitconsistsofacylindricalstatormagnetandacylmdrical rotorlnagnetmade丘omNeodylniumIron-Boron(Nd-Fe-B)materialbecauseofits excellentmagneticpropertieswhicharementionedearlier,Thedimensionsofbothstator

androtormagnetsisalsoillustratedWhereapieceofmagneticmaterial(,Odeg)covers partoftllestatorlnagnetmordertoinlprovetllerepulsivefbrcecharacteristicsasitwillbe explainedlater・Thestatormagnetconsistsoftwopiecesattachedtogetller、TY1eradial repulsivefbrcesbetweentllestatorandrotormagnetslnaketllerotorlevitatedstablyalong

theradialdirectionwheretheaxialdirectionisunstableandneedsacontrolled electromagnetinordertostabilizetllerotor・Duetosolnemanufacturingdefectsor fabricationdifficulties,thereissomemagnetizationasymnetryofmagnetsandasaresult tllefnbricatedmagnetsOftllesamematerialanddimensionsarenotidentiCaLSo,befbre settingtllemodel,bothofthestatorandrotormagnetsshouldbeselectedtobesinlilari.e‘

manypiecesofrotorandstatormagnetsshouldbepreparedandthefluxdensity

distributionofeachpieceshouldbemeasuredmordertoselecttllerotorandstatorleftand rightmagnetsthathaveconstantfluxdensitydistributionaroundtllesurface,inaddition thefluxdensitiesvaluesofbothleftandrightmagnetsshouldbeascloseaspossibleto

eachotheH

22Fi"舵eノe川e"/αM)ノID応q/rノカePMsecがo"伽〃

TheFEMmodeloftllePMsectionisshowninFig、1(b)Theaxialrepulsivefbrcesare calculatedusmgtlleMaxwell3-Dprogrammordertousetllisdatafbrdesigningtlle electrolnagnetusedfbrcontrollmgtlleunstabledirectionHowever,theradialfblCesare calculatedinordertoensuretllestabilizationalongtllatdirection.Asshownmthenlodel,

bothoftheleftandri=htstatorconsistsoftwopiecesofNd-Fe-Bperlnanentmagnetand

tllestatoriscOveredbyamagneticshuntmateriaL

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Mag j、 s)

JUdeK

傅鳴.

nlI

Unit:m、

S MaOcrialDimcnsIons

圏…Ⅷ(…‘…

N

StatorPM,Nd-Fe-B,‘`×,‘X8 MagneIicmntcri別IIron(S45C)ノ6,XI4dXB

《otorma四

Ⅱほに臣h、IHI【

magnet

(a)Structureofthesection (b)FEMmodelofthesection

Fig.lConfigurationandFEMmodelofthePMrepulsivetypelnagneticbearing

Thecalculatedaxialrepulsivefbrcesmcaseofusingonepieceandtwopiecesstatorsare showninFig.Z(a)nisclearfiPomtllecalculateddatatllattlleaxialfbrcemcaseofusing twopieceSstatorislessthanthefbrcemcaseofusingonepiece・Inadditiontllerangeof fbrcclmearityiswiderwitlltwopieces・Sotllestatorisdesignedastwopiecesbecausein tlliscasethefbrceneededfbrcontrollingtllatdirectionwillbelesstllanthefbrcemthe caseofusingonepiece,tllatmeanssmallandsnpleelectromagnetdesignisreqUired・Thc surfaceofthe叩perpartofthestatoriscoveredwithironshuntmaterialwithdifIerent centerangles・TWocenteranglesaresimulated,g0degreeand360degree、Attachmgsuch shuntmaterialaffectsbotllaxialandradialfbrcecharacteristics・I、Fig.2(b),theaxial repulsivefbrcewithoutattachmgtheironshuntandwithironshuntofcenterangles90 degrceand360degreeisshownTheironshuntofbotllcenteranglesdecreasestheaxial fiorcc,but90degreeispreferablebecauseofbetterlinearity・Decreasingtlleaxialrepulsive fbrceisdesirablefbrasimplecontroldesign・Furtllerlnore,tllisshuntincreasestlleradial repulsivefbrcealongz-directionandmakesitalwayspositivewhichisdesirablefbrbetter stability・Thisisclearlyillustratedin]Fig.3(a)Wheretlleradialrepulsivefbrcewithout attachingtheshuntandwith90degreeofironshuntisshown、Thenegativegradientofthe radialfbrcecharacteristics(i、e、positivestiffiless)contributetopassivestability・Theradial repulsivefbrcealongy-dircctionisalsocalculatedmbothcases(witllandwitlloutshunt)

andshownmFig、3(b)They当directionfbrcechangeslinearlywillltlledisplacelnentand

lncreasesalittlewhenthestatoriscoveredwithtllemagneticshunt.

10

505PC⑪巳&の戸{の百二⑪閂『甸貝く

PC②巳巳○屋四百(芯揖[呵浸く

4-2024-4-26--60246-10

Axialdi印k四CmemMmlm)

AxialdispkmcmantOnlm0

(a)Usingoneandtwopiecesstator (b)Withoutandwithmagneticshunt Fi9.2CalculatedaxialrepulsivefbrcescharacteristicsofthePMsection

-18-

■■。

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5251505(巴三国田富②。』巳。昌已三壱塁 284048100心心Ce一一【田冨の自己の彦窃己(読昌呵弓飼国

-11 0.8-04 -..、…△・・-1.Z-U、8-0.400.40.8、-4 と1.2-1.2 -0.8 -0.4

Z-dircctiondisplacement(m、)Y白diIcctiondisplacement(m[I0

lZ-dilectionfbrcecharacteristics (b)Y-directionfbrcecharacteristics

Fig.3CalculatedradialrepulsivefbrcescharacteristicsofthePMsection.

Z-dircctiondisplacementOnm) 1.2

(a)Zdilectionfbrcecharacteristics

Pannanent controlled

JnIP a回nE

Gapsensor

uapsensor

Stopperplate

Fig4Configurationoftlleaxialshaftpart、

3.Configurationoftheaxialslmftpart

TheconfIgurationoftheaxialshaftisshownmFig4,Wherethetwounitsoftlle

permanentmagnetsareinstalledaroundthecenterpoint;tllestructureoftllissectionis

explainedearlier.BasedonEarnshawtheorem,theaxialshaftisunstablealongtheaxial direction,soacontrolledelectromagnetismstalledtogenerateanattractiveforce,This fbrceismodulatedthroughacontrolsystemwhichreceivestheshaftpositionmfbnnation fomagapsensormstalledtotheleftsideoftheshaft・Theexplanationofeachpart mdividuallyisgivenmtllenextsUbsections、Astopperplateisplacedinordertostopthe

movementoftheshaftwhilenooperationFurtllennoreabalanceweigI1tisplacedatthe otllerendoftheshaftinordertokeCpitmeqUilibriumposition

3・IEルc加川cJg7zeM己Sig7z

TheEarnshawtlleoremstatesthat,atleast,onedirectionshouldbeactivelycontrolledin ordertoachieveastablenon-contactlevitationmmagnetstatic・so,anelectrolnagnet

deviceismstalledbesideanironplatefixedintlleshaft・Thedetailsstructureofboth E1ectromagnetandironplateareshowninFig4TheEMconsistsofanironcoreand0.6

,mndiametercoppercoilof683turn,8.91ohmresistanceandO・O6Z4henerymductance・

Thisdeviceisusedtogeneratetherequiredstabilizingfblce,IIlfact,theelectromagnet causestheflUxtocirculatemalnagneticloopWhenanalyzingsuchmagneticloop,an

-19-

、Z-0.8-0.400.40.81.2

●》●一・■

|』ゆ□●●。』』

■O O DO

 ̄再=。-s

 ̄⑪●

 ̄ ̄●■

●=と=

O■■ ロ巳.。、

■●■●-.

~ ̄.’

=-With山tmagnBticmaterial

-←Withmagneticmterial90deg

O■

hO

二三三二=一一二{三E二

0■

C O

D8

 ̄~いむCC-。②●-●--■

 ̄や

~● ̄

00 ̄

←■棹!●●■。。● ̄-■-。■■■■

。-甲■■■

~_.

~●~

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exacttheoreticalcomputationofthefieldisrarelypossibleandseldomreqUired・One usuallyworkswitllanalyticmetllodsOfapproximation,basedontllesimplifj/ing assumptionthattlleflux,exceptfbrintheairgap,runsentirelythrouglltlleironSmcetlle permeabilityofironisconsiderablylargerthanthatofair,tllemagneticfieldlinesleave theironalmostperpendicularly・TheEMfbrcecanbeexpressedasfbllows

涙―だ

一一

涙一万

。〃α’一乎一一

whereN,iaretheNoofturnsandcurrentofthecoilrespectively,xistheaxialgap,Aairis tlleareaoftheairgapbetweentheEMandironplate,川istllepemeabilityoftheair.

↓_

+L

4のLノ⑪

npl

』鼎佃

X1】Iに

Unit:、、

(b)Ironplate (a)ControlledEM

Fig、4ConfigurationoftheEMandIronplate.

53525150(庭)8衿&]①[助ロ日○垣。①[四

Lb

-1-■[

-I-U-f

u--口---口--乱

Axialgap(m、)

(a)FEMmodeloftlleEM (b)EMfbrcecharacteristics

Fig・SThecontrolledEMmodelandfbrcecharacteristiCs.

ThefiniteelementlnodeloftheelectrolnagnetdeviceisshowninFi9.5(a)wherethe attractivefbrceiscalculatedasafimctionoftheairgapandthecoilcurrentusingMaxwell 3-Dsoftware・TheEMfbrcevs・axialairgapcharacteristicsfbrdifferentcoilcurrentsare

showninFig5(b).TheaxialairgapchangesfieolnOto2mnandthefbrceiscalculatedat 0.24A,0.48Aand0.72Acurrent、TllefbrceisinverselyproportiOnalwiththeairgapand directlyproportionalwitllcoilcurrent、Inordertoachieveastablenon-contactlevitation,

theEMfiDrcecharacteristicsiscomparedwiththePMrepulsivefbrcecharacteristicsfbr

deterIniningtllesteadystateoperatingcurrentandgapThisinfbrlnationisneededfbr implementationofthecontrolsystemwhichisemployedtoadjustthecoilcurrentattlle

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steadystateoperatingpoint・TheEMsteadystateoperatingcurrcntissetatO48Aandif fbranyreason,tlleairgapischanged,tllecoilcurrentshouldbealsochangedmorderto keeptlleEMfbrceconstantallthetimefbrachievingstablelevitation

3.2dxjZJノg叩Sc"so7

Theopticalsensorisfastandhasagoodsensitivity;maddition,itismagnetically mdependent,simpleandcheap、Fortllesereasons,aphotosensorisusedfbrdetectingthe displacementoftheaxialshaft・ThestructureoftllephotosensorisshowninFig、6(a),

whereitconsistsofaliglltemittingdiode(LED)(GL513F)andaphotodiode(PD)(MI- 33H2D).TheLEDemitsUlelightandtllesllutterobstructstllelight・TheqUantityoftlle

Lightreceptionside 05 01

iVI2 ゴISectlonphot⑥。、。[

s成碗冒画[団{の。凶旦〔旨・目。、

-.ご=,------,.

-.ご=,------,.

005

---…・----6-.---…田---………----…ず---…

l⑪nuZ■ⅡⅡ四回qmKn上

~ ̄ ̄豆一一一一一・●・・.●。.●● ̄ ̄ ̄ ̄ ̄・・「●---●-.-■----...◆

●CCCロー■0■'■~~口PCCCc●●●--1■-■--●●●~●●-●。。■'--■■CC-C--・-勺一一■-■の。一・・● ひし・-----■--.sし。。●-.こ=----

、--T,--

-0.u

012-1O1 41

DiSpIacenmtOmD

JnSDlaCemeT

(a)Sensorstructure

(b)Outputcharacteristics Fig、6thephotogapsensorstructureandoutputcharacteristics.

incidentliglltonthebisectionphotodiodeischangedasthepositionoftheshaftis changedandasaresulttlledifferentialoutputvoltageischangedaswelLTllesensor

characteristicsisshowninFig6(b)

4.COnfHgurationoftllebalmncelDeam

イ.IBam"ce6eα〃WiZノbelecかo川ag7zetcMWam7

ThefirsttrailofmanufacturingoftllebalancebeamisshowninFig、7Itconsistsofabrass bar,atonofitsends,anironballisattachedandaMheotherend,analunmnumSample holderisplacedAsmalls]mtterisfixedattheholdersidewhereaverticaldisplacement sensorisalrangedandinstalledbesidetlleholderinordertodetectthedisplacementofthe bearnwhentllesampleisaddedtotlleholder・TY1issensoristllesametypeofUleaxialgap sensorusedfbrdetectingtheaxialshaftdisplacement,butitisonlyarrangedmdifferent waytodetecttheverticaldisplacement・ThemfbrlnationofthebeampoSitionistransfelred mmtllegapsensortoacontrolsysteminordertoadjusttlleattractionfbrceofan electrolnagnetwithironcoremstalledundertheironbalLThisEMattractionfbrCeis

changedaSthepositionofthebearnischangedinordertolKeeptllebeamlnequilibrium

horizontalposition、Asitisexplamedearlier,tlleEMreluclancefbrceneededfior stabilizmgtheaxialshaftisdirectlyprOportionalwiththesqUareoftheEMcurrentanditis

samefbrtheEMusedfbrkeepingthebeamhorizontaL

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(8)

eraneT

JnpallLonIrollec naHnBLRb囮凹uuI

Hunk nct

一冨冒=…-=---杯一一=--L`騨轤

Jean nnqi囮Iuhu

__’

Fig.7BalancebeamwithEMactuator,

Avoicecoilmotor(VCM)actuatorissuggestedtoreplacetheEMwherethestabilizing fbrceisproportionallmearlywithcurrent・ReplacingtheEMwiththisdevicewillincrease thesystemsensitivitywhichisdesiredfbrmeasuringtheslnallsamples・Anotherimportant aspectistllesaturationofEMironcoreandthemagnetichysteresis,itmcreasesthe

measurementerror.

イ.2Baノ[J"ce6ea川wjZZlvojcecoノノ川om7

TllemodifiedbalancebeamconfigurationisshownmFig、8.TheEMandironballare

replacedbyavoicecoillnotorastllebeamactuatortoavoidthedifficultiesmthedesign

andcontroLSomeofthesedifficultiesarethenonlinearityoftlleEMreluctancefbrce,tlle

colnplexdistributionoftllefluxintlleairgap,andthesaturationoftheEMcoremateriaL

TlleVCMattractionfbrceislmearlyproportionalwitlltllecoilcurrentandasaresult,tlle

systemmeasurementsensitivityisbeconlinghigherthanintllecaseofusmgEMwheretlle

fbrceisproportionaltotllesquareoftllecurrent.

手.38J'wc〃eqノンノieFCMα"cMie抑jMC川ilリノ伽伽〃o〃

TheconfigurationoftheVCMisshowninFig.9(a)itconsistsofanironyoke,afigureof eigImtcoppercOiloflOturnsand0.61mndiameter,andtwopiecesofpennanentmagnets areattachedtotheinternalsidesoftlleyoke・Thepemanentmagnetisconsideredasa sourceofastationeryflux,Thefbrceexertedonthecoilisgivenby

Fc.〃=B、/、lVj

WhereBistllefluxdensityinsidetllegap,Mstllenumberofcoiltums,ノistllelengtllof thepartoftllecoilwllichliesinsidetllegap,andjistllecoilcurrent、AsillustratedmFig、

9(a),thedirectionofthefbrceexertedonthecoilis叩wardaccordmgtolefthandrule・But becausethecoilisfixedandtheyokeisfiPee,tllereisareactiondownwardfbrceexertedon

theyokeasgivcnintheeqUatiOnbelow・Thisattractionfbrceexertedontheyokekeepsthe

balanceofthebeam.

F,、=F"庭=-F・ojl

TllesimulatedlnagneticfileddistributionoftlleVCMmodelbyMaxwell2-Dsoftwareis shownmFig.,(b).T11efluxdensityattllelmeW11ichliesmthemiddleoftlleairgap insidetheyokeiscalcUlatedusingtlle2-Dfiniteelementmetllod・Itisclear丘or、Fig.3-14

thatthefluxdensityattllatlmeisparabolic.

lermanCm

Jermancm okc

aIZnI TaEnCISCUL1uL

Fi窪.SBalancebeamwitllvoicecoilmotor、

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Balanccbeam

mDI

(伊日)、{目呂旨逼

“し

澪、

DiSplacemBntOnllD

(aWCMconfiguration 化)F1uxdensitydistribution

Fig・DVCMstructureandfluxdensitydistributioninsidetllegapatthecenter 5.ConfigumtionofthecompletesystemandprincipleolDeration

ThetOpviewoftllecompletesetupoftllerepulsivetypemagneticbearingbalancesystem isshowninFiglO・Theaxialshaftandtllebalancebealnareattachedtogetllerattl1e centerpoint・Thehybridlnagneticbearingsystemwhichincludestllepennanentlnagnet unitsandtheelectromagnetwithactivecontrolhelpsthesettobelevitatedstablywitllout

contact・ThelnostconⅡnonproblelnarisesmallconventionalbeambalanceistlleEiction atthefillcnⅡ、;thisproblemdecreasestheequiplnentsensitivity・Thenon-contactlevitation oftheproposedsystemovercomesthefiictionproblemseckingfbrbettersensitivity・

Tlleproposedmagneticlevitationmassmeasurelnentsystenlisbasedoninstallinga controlledbalancebeamandusesitasthemeasuringdevice,sotllemeasuremem sensitivityishigherthanthatoftlleconventionalmechanicalbearingsystelns・Also,tllis systemcanbeusedtodetecttherelativevaluewhichismassWheretheeffectofgravityis elinnatedlnsomeapplications,itisneededtodetectthelnasschangeofasamplewhere

tllischangeisresultingffomheatingorpressurizationSincethebalancebeamofthe systemisdesignedsothatthesampleholderandtheactuatoraredistantenough,itis convementtobeusedasathermobalancewhichiswidelyusedfbrthechenlicalanalysis・

Someoftlleseanalysissuchasdifferentialthennalanalysis(DTA)andthenno-gravimetric analysis(TGA)areusehlfbrmaterialcharacterizationapplicationS

TY1eprincmleoperationoftlleproposedsystemdependsontransfelTingtheadditionalnlass tothcactuatorcontrolcurrent・Whentllesampleisaddedtotlleholder,tllebeamis

distUrbedanditspositionischangedTheverticaldisplacementofthebeamisdetectedby thegapsensormstalledbesidetlleholderandbythehemofdigitallyilnplementedcontrol system;tlleactuatorcontrolcurrentischangedinordertogeneratetllefbrcenecdedto keeptllebeamatitsorigmalposition

TllefimctionofmassmeaSuringisconfirmedbyaddingsomesalnplestotheholderand noticingtllevoicecoilcmrentchange、Inordertoprovetllattllesystemmeasurestlle colTectsamplemass,somesamplesofknownmassesarealsomeasuredaftercalibrating thesystemThedetailsofexperimentalresultsofmeasurementandtlleevaluationoftlle systemmeasurementperfbnnanccssuchaslincarity,accuracy,precisionandrepeatability

willbegivenlater.

-23-

400

350

300

五0 200

150

100

50

0 2468101214

0,9G-00OG00●、●00 O0r00lo9牛十!D0。。01・・勺0,1

0.0。●.●ロロC●00,0

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碑麹

Pn ea

Controlled

electrolnagnet

 ̄、、I

Voiceioil

Gapsensor

~‐ ̄ ̄ ̄ ̄-- ̄ ̄ ̄ ̄---勺一一一一一一一一材弓F--.-----十一一一一一一一一一一一一一一一丁 ̄ ̄--- ̄---u

←-4。Ⅱ'1 h.Lcrq-~●■-

I00Ii8

i;:へ“

Ojh WwlN

。。P、

liiiwS

U・bn-_。 00

I0l0il N・r- 001080

:S

出E二F当一

二illiHii三r-臨扉-

1、

maglietsectlon

1---プーー誌蜘孟一 Mm.w●ightl/,

MainlDeam

 ̄ ̄ ̄--

xT

Y

H|柵-↓剛Ⅲ

L------------------0

Fi9.10Topviewoftllecompletesetupoftlleproposedbalaj【lcesystem.

6.Systemmodelingandcontroldesign

匝皿"αノゥノがcα/伽6!bLFqハノiMxjaMq/iα"α6α伽ceDea川

TlledynalnicmodeloftheaxialshaftisshownmFig、11(a).Forderivingasimple

ThedynalnicmodeloftheaxialshaftisshownmFigll(a).Forderivmgasnmplesystem model,someidealconditionsareassumed,Theseconditionsmcludenoleakageflux,no DCmagneticsaturationorllysteresismtlleelectrolnagnet,however,tlleperlneabilityof thecoreisassumedtobeinfinity・Tlledifferentialequationswhichdescribethemotionof thelevitatmgohjectarederivedasfbllows:

〃超一F(x)-Eh(x,j) ,Rj+LjLe

wh…(皇)肌川薑αX+〃

Theanalyticallnodeloftllebalancebcamshouldbealsoderivedinordertodesignthe beamcontroller・Thepllysicallawswhichgoverntllemotionoftllebeamareinvestigated WherethelnodelisshowninFigll(b)

川,jE二o

Ri+LjLe

川,雌川29-川,g-Fim(z,i)

WhercE,=jWBL

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(11)

LevitatingobjectControlledelectmmagnet

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(a)Shaftmodel (b)Beamlnodel

Fi窪.11Analyticalmodelsofshaftandbeam 52αO"肋ノノl27j"!P/e川e"ZZZrjO〃

Aftertheanalyticalmodelsofbothshaftandbeamarederivedandtllestatespace equationsareobtained,thecontrollersaredesignedusingthelinearquadraticoptimal controltechniquewheretheblockdiagrarnofshaftandbearncontrolsystemsareshownin Figl2.TheblockdiagramofthewholesystemwithcontrolisgiveninFig、13where4- channel,12bit,25KHzanalog-to-digitalconverterreceivesthevoltagesignalsfromboth oftheaxialandradialgapsensorswhichexpressthedisplacementofbothshaftandbearn Thesevoltagesignalsarefedtothecontrollerafieritisbeingconvertedintodisplacement signalsThecontrolleroutputispassedtothedigital-to-analogconverterandthenthe controlsignalsarefedtothernagneticbearingactuators(EMandVCM)throughpower

amplifiercircuits・

ThecontrolprocessstartswithrunningtheMTALABprogramtocalculatethecontroller feedbackmatricesandthengeneratingthereal-timecontrolsignalsbyexecutingthe

MTALBSIMULmKcontrollermodeLBythehelpofルpasssoftware,theexecuteddata iSsubmittedtotheDSPandafterthatthemagneticbearingsystemisoperatedltis

confirmedtllatthepreviouslydesignedcontrollerscouldachievestablelevitationofthe systemalongtheaxialdirectionwherethebeamCouldbekeptatanequilibriumhorizontal positionevenafteritissubjectedtoextemaldisturbance.

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Power

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7.Massmeasurementmdevaluationofthesystempermrmmces

AfterthesystemismanufacturedandtllecontrollersaredCsignedandimplementedaround aDSP,theexperimentsarecarriedoutonthesystemtoconfinnthefimctionofmass measuringandevaluatetlleperfbrmances・Intllefirstexperiment,somesamplesofequal rnassesareaddedgraduallytotllemassholderandremovedbythesarneway、Ineachtime

tllecontrolcurrentisnoticed,Tllecontrolculrentvs、samplemasscharacteristicsisshown

inFigl4(a)wherethebeamactuatorisanEMwitllironcore・Thecontrolcurrent variationismcreasedasthesamplemassinsidetheholderisincreasedAsshownmFigl4

〔b),tlledifferencemtllecontrolcurrentbetweentllemcreasingdirectionanddecreaslng whichisdefinedbythellysteresisisinvestigatedbyzoomingintoFigl4(a).Itisfbund tllatthesensitivityisqUitelowandtllevalueoftllellysteresisiseqUivalentto730}L9.and thenon-lmearityerroroftllecharacteristicsisabout5%ofthefilllscalecurrent.

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SamPlemass(mgDSamplemass(mg)

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8.ImprovementoftlleWstemmeasurementclmracteristics 8・IR印mcmgZノbeEM6eα'Mc伽加'6〕′αMcecojJ伽〃

BecausetheEMfbrceisproportionaltotllesqllareofthecoilcurrentandlheproblelns arisehomironcoresaturation,thesystemmeasurementcharacteristicsarenotsatisfactory・

nleEMisreplacedbyvoicecoilmotordevicewheretllefbrceisproportionaltothecoil culrentandthesourceofthefluxispennanentmagnets(PM,s)hlordertokeepunifbnn fluxdensitymsidetlleyokegapfbrcertainrangealongtllecenter,sonlepennalloyfilnls areattachedtothesurfaceofthePM,s;thishemfbrdecreasingthecmremhsteresisBy lllesamewaytlleexpemnentsarecarriedoutontllesystenlandsamplesofeqUalmasses areaddedglHduallyandremoved・Thecontrolcurentvs、samplemasscharacteristicsis showninFig、15(a).Itisfbundtllatthesystemsensitivityismcreasedtomoretllantwo times;tllellystersisisdecreasedtolOl』gandthenonlmearityerrortoabout1%・A1sothe readabilityoftlleSystemwasabout751LgasillustratedmFigl5(b).

8.2ReP〃cjl2g伽CQ〃ノα川伽m6ea川乙)′〃eα"αノ伽"、川ノzJ〃"beα川

Inordertomcreasethesystemreadabilityandsensitivitywllichistllemainobjectivefbr proposedsystemtheeqUalbrassbeambrassbeamiSreplacedbyunequalambeammade 丘omDuralun血wllichisliglltandstiffmateriaLTheannlengtlltotheholdersideis becon血gdoubletheamlengtllattheactuatorside,andtlleflatmassholderisreplacedby aknife-edgeone・Aftertllismodification,thesystemsensitivityisdoUbledasshownmfIg andtllenonlmearityerrorisdecreasedto0.2%asshowninFig、16(a)Wheretllereadability rcached3OILgasshownmFigl6(b).AnotllereXperilnentiscaneiedOutontllesystemto evaluateitsaccuracyandprecisionWherethereadingofthesystemiscomparedbytlle readingofaMattlerToledobalanceAB204-s(2209×0.1mg).Intllisexpelimentsome samplCofdifferentmassesintllerange金omO-100mgarepreparedandmeasure,firstby MettlerTolcdobalanceandthenbytlleproposedsystenl・AsshownmFig、17(a),the maxnnumdifferencemthereadingbetweenthetwosystelnswas0.2mg、hanother experimenteachsampleismeasuledbytheproposedsystemlnanytinlesandtllestandard deviationiscalculated・Itisfbundthatthemaxinmndeviationwasabout0.1mgasgiven

inFigl7(b).

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Fi巴.17Evaluationoftlleperfbrmancesoftlleproposedsystem(accuracyandprecision)

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Forthecontrolsystemswhichinvolveanintegratorattllefeedfbrwardpath,theproblem ofintegrationwindupariseswhereani叩utconstraintisincludedtoprotectthesystem TheintegrationwindupaffectsthesystemperfbrInancesanddecreasestlleabilityoftlle systemtorejecttheexternaldisturbancesWhichsometilnesleadstomsatiability、Ananti windupschelneisaddedtothebeamcontrolsystelnasshownmFi9.18(a).

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Afteraddingtheanti-windupscheInc,tllesystemcouldrejectlargedisturbancesandtllis helpstomcreasetllelneasurementcapacityofthebalancesystem・Theexperimentsare carriedoutonthesystemanditisfbundtllatsystemcapacitycanreachlgasshowninFi9.

18(b).

9.Conclusi皿

T11erepulsivetypemagneticbearingisriglltsuitedfbrmanufacturingsuchsystenlbecause ofitsnon-contactoperationW11ichmakestllesystelnmoresensitivethantlleconventional bearingbalances、Moreover,itissmgleaxiscontrolledandasresult,asimplifiedcontrol schemeisneededfbrcompletelystablelevitation、Thedesignprincipledependsonusmga balancebeamwitlltwoendsfbrtllemeasunng,whereatoneend,themassholderis locatedandanactuatorislocatedontheother・Ihisenablestheusertoclinmnatetheeffect

ofgravityandasaresult,measuresthelnassoftllesanlple・Thebalancebeamisdesigned sotllattllesampleholderandtheactuatoraredistant;sotllissystemcanbeusedtodetect tllechangemtllelnassofasampleasafimctionofacontrolledtemperatureand/ortinle wllichisknownastllerlnogravimetericanalysis(TGA).Theexperimentalresults confirlnedtllatthesystemcanmeasuretllemassofthesanlpleswitllsatisfactory

measurementperfbnnances.

hfilture,tlleplanofworkwillconcernwitllusinganothercontroldesignteclmiqUesuch asH-oocontrolWhichconsiderstllemodeluncertaintysuchasumnodeledhigh丘eqUency dynanmcs,neglectednon-1inearties,andplantparameterperturbationsdueto environmentalfactors・Usingsuchcontro1teclmiqUewillincreasetllesystelnlDbustness

andinlprovetllesystelnperfbrmancesandasaresulttllemeasurementerrordecreases.

References

[1]A・Hussien,T,Okada,TOhji,S・Yamada,andM、Iawhara,“Arepulsive-type magneticbearingnncro-massmeasurelnentsystemandmeasurementofresolution",

Tm"Mがo"q/・伽MZgMjcSbcjel1WMW",voL4,no、2,pp51-55,2004

[2]AlaaA・Hussien,TomotadaOkada,TakallisaOllji,SotoshiYamadaandMasayoshi IWallara,“Investigationoftheconfigurationandcontrolofarepulsive-typemagnetic levitationsystemusedfbrlnicro-massmeasurement"P'wee伽gQかABI砂SE4,.,

JUne2004,Kyushu,Japan

[3]T、Okada,A1aaA・Hussien,T・Ohji,S・Yamada,andlnasayoshilwallara"APennanent Ma印etRepulsiveTypeMagneticbearingBalanceSystem,,ProceedingsqMbe3〃

・ノZIPα〃AzJMJノメα,jVbwZba伽肌ノb〃比〃"〃o'MZ2pノjcaがo"sq/Eノcc加川cJgMic Pノbe"o〃e"αj〃Eノecmcaノα"αMCCA〃jcaノ&〕入y花川.pp53-57,January2004,Auckland,

NewZealand.

[4]A,Hussien,T・Okada,T・Ollji,M,Iawhara,andS,Yamada"Improvelnentoftlle meamenlentcharacteristicsofaInagneticbearingbalancesystenf,,Z7wzMcがo〃q/、伽 MJg7zeZjcSbcjel【W/〔ノヒZpα",vol、5,no、2,pp.,7-100,ZOO5.

[5]A1aaA・Hussien,S、Yamada,andMIawhara,T,Okada,andT、O11ji"Applicationof tllerepulsive-typemagneticbearingfbrmanufactulingmcromassmeasurement balanceequipment,,,」EEE伽"Mcがo〃Q/MJg7ze伽,vol41,nolO,pp3802-3804

0ct2005.

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学位論文審査結果の要旨

-.当該髪f之諭Xに対上Z,_妥成11.霊Z且.qL且に第.廻諭文審査委壜会迄關催L`-2-回窪.1日.1旦腫 行われた口頭発表後に第2回論文審査委員会をFMiL討識した結果,以下の通り判定した。

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本研究は,1111''1不安定特性をもつ永久磁石反発磁気lIilll受をデジタル制御により安定させた非接liIIl

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CCD●●□●-.-CCC・●●●●●●■●c-DDCC●●●●CCC●●・● ̄■●・ ̄ ̄■ ̄●■DC■■● ̄ ̄●■ロ゛c●●●● ̄●CO ̄CDCCC● ̄●●●●●●● ̄●●・●●・・●ロ●●●●●●●●PCC・CCCCC ̄ ̄■ ̄ ̄ ̄ ̄ ̄●●●●●● ̄●●●●のCCCの ̄● ̄ ̄ ̄ ̄ロローロロ・CCC・の-■●●。●⑤

のとして工学的|ご重要であり,以下にその研究成果を列記する。

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(1)永久磁石反発磁気llilll受の磁気回路椛成の設計

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?M礎エゴ!Z壷磁気』IMI鷺92磁気厚1鴎と反発力猿惟②閣侭に豆!)工:、磁気Z:vLZf回路を提案LL鉱元 il:9,11塁1iYj1tによ・12錆性L9q賑1111量行kLJZ発力:_遡り性1-縫麗朧在.ど査制jmM菖雄p雄護itと迄2-

(2)質11(測定用のパランサビーム系の検討

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測定質:11t用のバランサビーム系にボイスコイルモータを適用し,バランサビームの非接lIlllでの安定

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化,ならびに測定質:爪変化によるバランサ位|if移動から生ずる誤差発生を抑制することを実現した。

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討した内容

であり,i1j士(工学)iiiii文に値するものと判定した。

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