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1、山東大學(xué)碩士學(xué)位論文對接TIG焊熔池幾何形狀參數(shù)檢測及熔透控制摘要TIG焊作為一種重要的機械制造熱加工工藝,在工業(yè)生產(chǎn)中應(yīng)用十分廣泛。為保證焊接質(zhì)量和提高焊接生產(chǎn)率,必須實現(xiàn)焊接過程的自動化和智能化。國內(nèi)外對此開展了大量研究,但絕大多數(shù)都是針對T[G堆焊的情況。本文研究對接TIG焊熔池幾何形狀參數(shù)的視覺檢測與熔透控制問題。根據(jù)薄板對接TIG焊試件容易發(fā)生熱變形的情況,對實驗系統(tǒng)進行了改進,通過檢測電弧電壓來反映試件熱變形造成的弧長變化。針對試件對接所造成的錯邊與對中問題,改進了圖像處理算法,定義了熔池偏離
2、系數(shù)。利用普通CCD攝像機拍攝出了清晰、完整的對接TIG焊熔池圖像,提取了熔池邊緣。開展了靜態(tài)試驗和動態(tài)試驗,檢測出了不同工藝條件下的熔池幾何形狀參數(shù)。利用BP神經(jīng)網(wǎng)絡(luò)模型分析了正面熔池形狀參數(shù)與背面熔寬的定量關(guān)系。在本文所用的實驗條件下設(shè)定了熔透的判定標(biāo)準(zhǔn)(當(dāng)背面熔寬在3~5mm內(nèi)時,就認為試件熔透符合要求)。根據(jù)正面熔池寬度來預(yù)測背面熔寬。設(shè)計了以正面熔池寬度為被控制量、焊接電流為控制量的模糊控制器,開展了薄板對接TIG焊熔透控制試驗,結(jié)果表明所研制的控制系統(tǒng)具有一定的控制效果。關(guān)鍵詞:對接TIG焊,
3、熔池幾何形狀參數(shù),視覺檢測,神經(jīng)網(wǎng)絡(luò),模糊控制山東大學(xué)碩士學(xué)位論文、VeldPoolGeometryMeasurementandPenetrationControlinTIGWeldingofButtJointsABSTRACTAsanimportantmanufacturingtechnology,tungsten-inert—gas(TIG)weldingiswidelyusedinindustry.Itisnecessarytorealizetheweldingprocessautomationan
4、dmakeitintelligentforassuringtheweldingqualityandimprovingweldingproductivity.Largeamountofresearchworkhasbeenconductedinthisfieldathomeandabroad,butthemajorityofwhichareconcemedwithbead·on-plateTIGwelding.Thispaperintroducesasystemformeasuringtheweldpool
5、geometrywithvisionsensorandcontrollingthepenetrationinTIGweldingofbuttjoints.ConsideringthefactthatsheetworkpieceseasilyoccurthermaldistortioninTIGweldingofbuttjoints,theexperimentalsystemismodified.Thearclengthvariationresultedfromthethermaldistortionofs
6、heetworkpiecesisrealizedthroughsensingthearcvoltage.Inallusiontothemisalignmentandseamtrackingproblemsinbuttjoint,theimageprocessalgorithmisimproved,acoefficientreflectingthedeviationofweldpoolisdefined.TheclearandwholeTIGweldpoolsurfaceimagesofbuttjointa
7、recapturedbyusingthecommonCCDcamera,andtheedgeofweldpoolatuppersurfaceisextracted.Thestaticanddynamicexperimentsarecarriedout,andtheweldpoolgeometricparametersindifferentweldingconditionsareobtained.Therelationbetweentheweldpoolgeometricalparametersandthe
8、backsideweldwidthisanalyzedbyusingBPneuralnetworktechnology.Acriterionforpenetrationextentissetunderthetestconditionsisinthisstudy(whenthebacksideweldwidthintherangeof3-5I/Lrn,thepenetrationisregardassatisfactory).T