外文翻译自动焊接操作系统精品.docx

外文翻译自动焊接操作系统精品.docx

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外文翻译自动焊接操作系统精品

Anautomatedweldingoperationplanningsystem

forblockassemblyinshipbuilding

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）

（ConnectionType=1）

（DirectionofAssemblyBasePart=notConnectionDirection）

（PartFrom=notAssemblyBasePart）

（PartTo=notAssemblyBasePart）

THEN（WeldingPosture=V）

AnexampleofasmallsubassemblyisshowninFig.4.Inthiscase,thereareÞveparts,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）

（PartFrom＝notAssemblyBasePart）

（PartTo＝notAssemblyBasePart）

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,steelsusedforblockassemblyaremildsteelsandhightensilesteels.Mild