TheresearchandfutureprospectsofthearcsensorWeldseamtrackingistoensurethatthepremiseofqualityandweldingautomation,andsensorsarethebasisforachievingthisprerequisite.Weldingsensoraccordingtothedifferentwaysofsensingadditionalsensorscanbedividedintotwomajorcategoriesandarcsensors.Mostofthetraditionalseamtrackingisanadditionaltypeofsensor,forexample,touchsensors,electromagneticsensorsandavarietyofopticalsensors,suchsensorsisthesensorandthecommonproblemsistheseparationofthearc,thesensordetectionpointarcwithacertaindistanceaway,alargearcintheweldingseamwillaffecttrackingperformance.Thearcsensorusingthearcweldingprocess,thecurrentwaveformorthechangeofarcvoltagewaveformsobtainedARCCentrehasdeviatedfromtheseamasthesensorinformationandrealtime,trackingwell.Arcsensorisitsbiggestadvantageoftheanti-arc,hightemperatureandstrongmagneticfieldsarestrong,anditisalwaysconsistentwiththeoverallarc,simplestructure,lowcost,atpresent,arcweldingsensorasameansofsensorsmuchnationalattention,manyforeignweldingequipmentresearchandmanufacturingorganizationsareworkingtodevelopthisarea.Earlystartofthestudyofindustrialcountries,havedevelopedavarietyofarcscanforms(suchasdoublewiretie,swingandrotation)ofthearcsensor,suitableforsubmergedarcwelding,TIGandMIG/MAGweldingmethods,suchasdifferent,andsomehavebeenusedinweldingproduction.Manycountriesontheproductionofarcweldingrobotequippedwithswingarcsensortrackingdevice.1Classificationofarcsensor1.1SwingscanningarcsensorSwingarcscanningiscurrentlythemostwidelyusedsensorofaweldingarcsensor,whichneedsaswingarcsensordevice,inthehorizontaldirectionoftheweldseamtrackingbackandforthandachieve.Usedinarcweldingrobotsensorsdonotneedtoswingonaswingdevice,drivenbytherobotarmforhorizontalswingtotorch.However,theimpactofstructuralfactorsbyrobots,robotbeatfrequencyof10HzisgenerallylessasshowninFigure1a.Inthehigh-speedarcweldingandweldlargecases,thetrackingperformancewillbeaffected.MKODAMAinventedanelectromagnetichigh-speedswingarcsensor,thesensoronbothsidesofthisarchasapermanentmagnetandexcitingcoil,whentheexcitationcoiloftheDCcurrentthroughacertainfrequency,theconductiverodswingwillproduceacertainfrequencytoachieveseamtracking.Thishigh-speedswingarcsensorgenerallycanbeatfrequencyadjustablebetween040Hz,04mmadjustableswing,themaximumweldingspeed400mm/sec.Itfeaturessmallsize,lessweight1Kg,thestructureshowninFigure1b.1.2DoublewireparallelarcsensorThearcsensorusingtwoseparateparallelarcweldingontheworkpiece,theweldingwirearoundthetwocurrent(voltage)differencebetweentheprovisionoftwoelectricarcweldinghasdeviatedfromthecenterlineofinformation,thuscanberealizedseamtracking.Accordingtothetwoarcparametersandcomparethedifferencebetweenthereferencevaluecanalsobeachievedbetweenthetipandthesurfacedistanceadjustment.Thissensingmethodistheuseofarcstaticcharacteristicparameterschangeasthesensorsignal,usethesametwoparameterswereindependentlooppowerparallelgroovewelding,torchstructuremorecomplex,therearecertaindifficultiesinimplementation,sotheutilityonrestricted.1.3high-speedrotatingarcsensorscanThearcsensortorotatethearcinsteadoftheswingarc,therotationfrequencyupto100Hz.Twentiethcentury,theeighties,NKKCorporationofJapanhasinventedarotatingarcsensor,andappliedtothenarrowgapweld,theprincipleshowninFigure2:conductiverodastheconeofthebus,aroundtheconeaxisofrotation(revolution),andnotconductingrodarounditsaxisofrotation(rotation),andthemagnitudeofconemovementatthetopofasmalldiameterofthisstructureistoadjustthescanningconeangleadjustment,thesensorneedtouseageardrive,thestructurelarge,affectingtheaccessibilityofweldingtorch.NKKCorporationofthistechnologyinships,boilersandstructuretobeappliedinproduction,andachievedremarkableresults.CHKimKoreaproducedahigh-speedrotatingarcsensor,showninFigure3,thesensortipdependontheeccentricitytoachievethearcoftherotatingtipoftheeccentricityisthearcradius.Althoughitsrotatingbodyisrelativelysimple,compact,butitshigh-speedrotation,thewiretipmustbeinthesamerotationalspeed,whichexacerbatedthetipoftheloss.GermanyU.Diltheyalsodonealotofhighspeedrotatingarcsensorresearch,productionandmadethearcseamtrackingsensors.InChina,startingfromthelateeighties,toTsinghuaUniversity,AcademyofPanJiluanresearchgroupheadedbytherotatingarcsensorhasdonealotofresearchwork,andhasmadevaluablescientificresearch.In1993,TsinghuaUniversitydoctoralstudentinthedoctoralstudentfeesLiaoswordjumpagriculturalresearch,basedonthesuccessfuldevelopmentofahollowshaftmotor-drivenrotatingscansensors,andaccesstoanationalpatent,showninFigure4.Thishigh-speedrotatingarcsensorscandesignusingthehollowshafttothehollowmotorastheprimemover,skewconductiverodthroughthehollowshaftmotor.Inthehollowshaftend,throughthecoaxialbearingsinstalledaligningconductiverod,theconductiverodeccentricpositioniszero,-aligningbearingscanbeinstalledonthemotorshaftorhousing.Thebottomofthehollowshaft,theeccentricsleeveinstalledintheshaft,theeccentricsleevekitinstalledintheeccentrichole,aligningbearingkitinstalledintheeccentrichole,conductiverodinstalledinthebearinghole.Bytheeccentricityofthedepartmentconductingrodinsideandoutsidetherespectiveeccentricityeccentricsleeveandinnereccentricrelativetotheangleoftheeccentricsleeveanddecidedtoturn.Whenthemotorrotates,thebearingswillbestruckdownasataperedconductivebusbararoundtheaxisasthemotorrevolution,orasconicalswing.Inrecentyears,NanchangUniversityinJiangxiProvinceKeyLaboratoryofroboticsandweldingautomationonthebasisofthishigh-speedrotatingarcsensorscanandvibrationinsmallareassuchasin-depthandmeticulousresearch,andwasfurtherimproved,producedaprototype,theprototypeinstalledinthearcweldingrobotsuccessfullycarriedoutinrealtimetracking,Figure5fortheinstallationofthehollowshaftintherobotrotatingarcsensor.2arcweldingperformancesensor2.1weldarcsensorRotatingarcweldingandarcforthesensororinastraightlineswingweldwhensignificantlydifferent,thedifferentmovementsoftheweldingarcweldunderwayhavebeenstudied,Figure6forthreekindsofarcweldingduringexerciseseamformingcomparisonchart.Rotationinthearcmode,thewidthoftheweldmovementpatternthantheothertwoaslightincreaseinpenetrationhasbeenreduced,weldreinforcementslightlyreduced,duetohigh-speedrotationarc,dropletbytherotatingcentrifugalforcetheroleofthepooltothesurroundingfired,resultinginincreasingthewidthofthepool；rotationfrequencyofthelargerarcofrotation,apointarcinthereducedlengthofstay,andaccordingly,thearcforceontheroleofpoolatthebottomofshorteningthetimepenetrationdecrease；theeffectofcentrifugalforceandthescopeoftheexpansionofthearc,weldreinforcementdecreases.Seamweldinginthehorizontalangle,high-speedrotatingarcformingsignificantlyimproved,theprotrudingshapeoftheweldarcimprovedhigh-speedrotation.Thehorizontalangleofthehigh-speedrotatingarcweldwerestudiedweldingatthehorizontalangle,therotatingarcpressureactingonthemoltenpoolonthesurfaceoftheeffectofreduceddispersionandimprovedthesmoothnessoftheweld.Rotatingweldingonbothsidesoftheweldpenetrationinalloftheincrease,andtendtotheweb,itisbecauseofthehigh-speedrotatingarcandarcpowertoheatevenlyscatteredaround,reducingerosionofthearcrootoftheweldpooltheroleoftherotationarcoftheweldpoolwillproducestirringforce,weakenedthemoltenpoolofmetalgravity,Figure7isastraightlinerotatingarcweldingandweldweldinganglecontroldiagram.Intheactualuseofrotatingarcweldingsensor,adjusttheanglebetweenthegunandthewebtogetgoodwelds.2.2arcsensorresearchinhigh-speedweldingIntheactualweldingproductioninordertoimproveproductivity,oftenrequirehigh-speedwelding,otherweldingsheetmetal,inordertoavoidweldingtowear,butalsoneedhigh-speedwelding.Inordertostudythehigh-speedrotatingarcweldingsensorperformance,threekindsofarcmovementpattern(ie,thearcinastraightline,swingmovementandhigh-speedrotation)weldingwasstudied.Figure8showsthemovementpatternofthreeweldingarcwelddiagram.Linearmotioninthehigh-speedweldingtorchwhentheweldispoor,thereareundercutandweldtherewasahumpweldmetal,whichisduetohigherweldingcurrent,weldingspeedfaster,then,arcweldpooltheroleofliquidmetalinthebackofastrong,deepcrater,andnotenoughliquidmetaltofillthecrateronbothsides,thuscreatingabitingedge.AsshowninFigure8a；torchswingingmotioninthehigh-speedweldingoftheweldasshowninFigure8b,weldwavy,andtheshapeispoor,severelyundercut；Figure8cisahigh-speedrotationweldingtorchintheweldwhenthemap,weld,andnoundercut,becausethehigh-speedrotationarctoarcanddispersionforcesonthemoltenpool,craterdepthdecreases,reducingthearcofthehigh-speedrotationarconthebackoftheroleoftheliquidmetalpoolthusformingagoodweld.High-speedrotatingarcweldingrobottrackingcontrolofhighspeed,thesampleforthethicknessof3.2mm,500mmlong,wavylapjoint,theweldingcurrentis300A,therotationfrequencyis50Hz,thetrackingspeedof120cm/min.MKODAMAdevelopedhigh-speedelectromagneticdriveswingarcsensorintheweldingcurrent530A,whentheoscillationfrequencyof20Hzweldingspeedcanreach120cm/min.3,amathematicalmodelofarcsensor3.1ThemathematicalmodelofthestaticarcsensorStaticmodelreferstotheatmosphere,welding,powersupplyparameters,wirefeedweldingtorchandtheworkpiecespeedanddistanceareconstant,stablearcburningconditions,therelationshipbetweenthevariousphysicalquantities.Theresultsshowthattheexternalcharacteristicfeaturestoeasethepowerdown,thetorchheight(H)andthecurrentaveragevalue(I)therelationshipbetweentherangecanbeusedasalargelinearsystemtodealwith.Workinthearcbasicfixed(fixedwirefeedspeedandtheexternalcharacteristic),thearcsensorstaticmodelis:H=-KstI+CWhere:Kstfortheweldingtorchheightandtherelationshipbetweenweldingcurrentfactor；Iforthecurrentsamplevalue；Cisthemaximumtheoreticalvalueoftheweldingtorchheight.IfKst,Cisknown,thenIcancalculatebasedoncurrentactualvalueoftheweldingtorchheightH,andthencomparedwiththegivenvalue,thedifferenceistheamountofweldingtorchheightadjustment.3.2ThedynamicmathematicalmodelofarcsensorDynamicmathematicalmodelofarcsensorquantitativelydescribestherelationshipbetweeninputandoutput.Studiessuggestthat:Forthedynamicresponsewithexcellentweldingpower,itsdynamiccharacteristicscanbeconsideredastheproportionofoutsidelinks,the