外文翻译自动焊接操作系统文档格式.docx
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Kyu-KabCho*,Jung-GuySun,Jung-SooOh
Abstract
Theblockassemblyprocessisoneofthemostimportantmanufacturingprocessesforshipbuilding.Sinceblockiscomposedofseveralsteelplatesandsteelsectionswithpredeterminedshapesaccordingtoshipdesign,theweldingoperationplanningtoconstructablockisacriticalactivityforshipbuilding,butthisactivityhastraditionallybeenexperiencebased.Thus,itisrequiredtodevelopanautomatedweldingoperationplanningsystemtoassembleblocks.Thispaperdescribesthedevelopmentofanautomatedweldingoperationplanningsystemforblockassemblyinshipbuilding.Basedontheinformationaboutparts,topologicalrelationshipbetweenpartsandassemblysequencesforblock,thedevelopedsystemperformsthedeterminationofweldingpostures,weldingmethods,weldingequipmentandweldingmaterials.Thedevelopedsystemimplementedsuccessfullyforrealblocksconstructedinshipyard.
Keywords:
Blockassembly;
Expertsystem;
Operationplanning;
Weldingprocess
1.Introduction
Shipbuildingistraditionallyalabor-intensiveassemblyindustrythatemploystheweldingprocessasabasicproductiontechnology.Inshipbuilding,thereareseveraltypesofmanufacturingprocessplanningforcuttingandbending,assembly,out-fitting,anderection.Amongtheseprocessplanningactivities,theassemblyprocessplanningisbyfarthemostimportant,sincetheconstructionprocessforahullblockcomprisesapproximately48~50%ofthetotalshipbuildingprocess[1,2].Themainoperationforblockassemblyistheweldingoperation.Theweldingoperationplanningproblemsinblockassemblyareverydifficulttosolvebecauseallblocksaredifferentinsize,type,andconstitutingsub-assembliesthatdependonthetypesofships.Also,sincethisactivityhastraditionallybeenexperienced-based,weldingoperationplanninginshipbuildinghasbeenperformedmanually.Thus,itisveryimportanttodevelopanautomatedwelding
operationplanningsystemforshipbuilding.Thereisrelativelyverylittleliteratureavailableonautomatedweldingoperationplanningsystemsforshipbuilding[3,4].
Thispaperdealswiththedevelopmentofanautomatedweldingoperationplanningsystemforblockassemblyinshipbuilding.Therule-basedexpertsystemforweldingoperationshasbeendevelopedusingSmartElementsasanexpertsystemtool.Thedevelopedsystemisdemonstratedandverifiedbyusingactualblocksintheshipyard.
2.Developmentofanautomatedweldingoperationplanningsystem
2.1.Systemframework
Theautomatedweldingoperationplanningsystemdevelopedinthispaperconsistsoffourmodules:
weldingposturesmodule,weldingmethodsmodule,weldingequipmentmodule,andweldingmaterialsmodule.TheframeworkofthissystemisshowninFig.1.
2.2.Determinationofweldingpostures
Thismoduledeterminesthepostureoftheweldingoperator.Weldingpostureisreasonedbyconsideringconnectiontypesandpositionaldirectionbetweentwoconnectedparts,directioninformationofassemblybasepart,existenceofturnover,andassemblylevel.
Connectiontypesareclassifiedintobutttype(B)andfillettype(T),asshowninFig.2.Thefourtypesofweldingpostures,downposture(D),overheadposture(O),horizontalposture(H),andverticalposture(V),areconsideredinthispaper,asshowninFig.2[5,6].Themoststableandeasiestweldingpostureisthedownweldingposture,andthemostdifficultoneistheoverheadweldingposture.Theweldingoperatordeterminesanefficientweldingpostureaccordingtotheworkingconditions.
Forrelationshipofconnectionbetweentwopartsthatarewelded,onepartisconsideredasthebaseandtheotherisconnectedtothebase.ThepartthatisconsideredasabaseisrepresentedasPartFromandtheotherthatisconnectedtothebaseisrepresentedasPartTo.
Thelevelsofblockassemblytoassemblesteelplatesandsectionsintothefinalblockareclassifiedintosubassembly(SA)level,unitblockassembly(UBA)level,andfinalblockassembly(FBA)level.Subassemblylevelsmaybedividedintosmallsubassembly(SSA)levelsandintermediatesubassembly(ISA)levelsaccordingtothesizeandweightofthesubassemblyasshowninFig.3.
Fordeterminingweldingpostures,theblockassemblylevelsareclassifiedintotwogroups.Thefirstgroupisthesmallsubassemblylevel;
thesecondgroupconsistsoftheintermediatesubassembly,theunitblockassembly,andthefinalblockassemblylevels.Thereasonforthisgroupingisthatthereisnoturnoverprocessinthesmallsubassembly
level,buttheassemblylevelsbelongingtothesecondgroupmayhaveturnoverprocesses.Turnoverprocessescausethechangeofweldingposturesthataredeterminedbeforetheturnoverprocess.
2.2.1.Determiningweldingposturesinthefirstgrouplevel
Thefollowingareexamplesofrulestodeterminetheweldingpostureforasmallsubassemblylevel.Theconnectiontypesofweldingjointsbetweentwopartsusedinthisruleare:
Butttype(0)andTtype
(1).
(1)IF(PartLevel=SmallAssembly)
(ConnectionType=1)
(DirectionofAssemblyBase=ConnectionDirection)
(PartFrom=notAssemblyBasePart)
(PartTo=notAssemblyBasePart)
THEN(WeldingPosture=H)
(2)IF(PartLevel=SmallAssembly)
(DirectionofAssemblyBasePart=notConnectionDirection)
THEN(WeldingPosture=V)
AnexampleofasmallsubassemblyisshowninFig.4.Inthiscase,thereareÞ
veparts,andtheassemblybasepartsareAandB.TherelationshipsbetweenthepartsarelistedinTable1andtheresultsofthedeterminationofweldingposturesforthisexampleareshowninTable2.
2.2.2.Determiningweldingposturesinthesecondgrouplevels
Inthesecondgrouplevels,informationfordeterminingweldingposturesisthesameasforthesmallsubassemblylevel.Weldingposturesaredeterminedbetweentheassemblybasepartandotherpartsthatareconnectedtotheassemblybasepartinasimilarwaytothesmallsubassembly.Otherweldingposturesaredeterminedbetweenpartsthatarenotanassemblybasepart.Ifturnoverprocessesexist,thedirectionoftheassemblybasepartischangedatanangleof180°
andtheweldingpostureisalsochanged.Anexampleoftherulesforthesecondgrouplevelsareasfollows:
(1)IF(PartLevel=notSmallAssembly)
(ConnectionTypeis0)
(DirectionofAssemblyBasePart=ConnectionDirection)
(PartFrom=notAssemblyBasePart)
(PartTo=notAssemblyBasePart)
THEN(WeldingPosture=H)
(2)IF(PartLevel=notSmallAssembly)
(ConnectionType=0)
(DirectionofAssemblyBasePart=notConnectionDirection)
THEN(WeldingPosture=V)
2.3.Determinationofweldingmethods
Thismoduledeterminestheweldingmethodsbasedonweldingposturesbyrule-basedreasoning.WeldingmethodsusedinthispaperaresummarizedinTable3,accordingtotheconnectiontypesofweldingjointsandweldingprocesses[7].
Ingeneral,thereareseveralweldingtechniquessuchasbrazewelding,forgewelding,gaswelding,resistancewelding,inductionwelding,arcwelding,andspecialwelding.Consideringthefeaturesofshipbuilding,theweldingprocessusedintheshipyardisthearcweldingprocess.Arcweldingisaprocessinwhichcoalescenceisobtainedbyheatproducedfromanelectricarcbetweentheworkandanelectrode[8].
Arcweldingisclassifiedintoseveraltypes,accordingtotheweldingmechanismssuchasshieldmetalarcwelding(SMAW),fluxcoredarcwelding(FCAW),submergedarcwelding(SAW),andelectrogasarcwelding(EGW).SMAWisoneoftheoldest,simplest,andmostversatilejoiningprocesses.Currently,about50%ofmostindustrialandmaintenanceweldingisperformedbythisprocess,butthisprocessisusedapproximatelylessthan5%atmostlargeshipyards.InFCAW,anelectrodethatistubularinshapeisused,andifnecessary,theweldingareaisshieldedbycarbondioxide.InSAW,theweldarcisshieldedbygranularflux,consistingoflime,silica,manganeseoxide,calciumfluoride,andothermaterials.Thefluxisfedintotheweldzonebygravityflowthroughanozzle.EGWisusedprimarilyforweldingtheedgesofsectionsverticallyinonepass,withthepiecesplacededgetoedge(butttype)[9].
Tobuildtheknowledgebaseforthedeterminationofweldingmethods,knowledgeisaquiredfromweldinghandbooksandexperts.InputinformationofthismoduleisgeometricalinformationthatisprovidedfromCADsystemandtheweldingposturedeterminedbyweldingposturedeterminationmodule.Theknowledgeisrepresentedbyrules.Theexamplesoftheruleforthedeterminationofweldingmethodsareasfollows:
(1)IF(ConnectionType=0)
(Groove=none)
(WeldingPosture=O)
(6≤Thickness≤50)
THEN(WeldingMethod=SMAW-MANUALBUTT)
(2)IF(ConnectionType=1)
(LegLength≥4.5mm)
(WeldingPosture=O,H,V)
THEN(WeldingMethod=FCAW-FILLET)
2.4.Determinationofweldingequipment
Thismoduleselectstheappropriateweldingequipmentbyrule-basedreasoningbasedoninformationaboutweldingposturesandweldingmethods.Table4showstherelationshipbetweenweldingmethodsandweldingequipment.Afterdeterminingweldingmethods,weldingequipmentisautomaticallyselectedbyusingtheinformationcontainedinTable4.
2.5.Determinationofweldingmaterials
Thismoduledeterminesthemostproperweldingmaterialsbyrule-basedreasoning,basedoninformationaboutweldingpostures,methods,andequipment.Ingeneral,steels