外文翻译CNC.doc
附录A:英文资料AschematicdescriptionforproposedtoolpathgenerationandcontrolmethodisdepictedinFig.7.Intheproposedmethod.,compositecuttercontactdata,whichincludethesplinefunctionsfortheCClocation(C)andthesurfaceprinciplenormal(N),thepresetCCvelocity(cV),andthetoolinclinationandtiltangles(and),areloadedtotheCNCmachine.IntheCNCinterpolator,theCLpathiscalculatedinrealtimesoastomeetthedesiredCCvelocityalongtheCCpath.Consequently,thecutteroffsettingalgorithmisimplementedintheCNCinterpolator.AsisshowninFig.7,aglobalfeedbackloopisclosedbytheinterpolator,whichcanmonitorthepracticalCClocation(*C)inrealtimeandcompensateforthedeviationerrorfromthedesiredCCpath.Inaddition,on-lineadaptationofthefederate(i.etheCCvelocity)canbeintroducedtoaugmentthemachiningaccuracyandefficiency.Forinstance,wecanslowdownthemachining(byreducingcV)astheCCdeviationerrorincreasessignificantlyandspeedupthemachining(byreducingcV)asthedeviationerrorisalwaysnegligible.Noticethatavariablefederate(duetoon-lineincreasingofdecreasingcV)canbeadoptedonlywhenitdoesnotcauseunacceptabledegradationinotherfederate-dependentcuttingeffects,suchascuttingtime,toolwear,surfaceintegrity,etc.()(coscossincossin)ctccLCrNrrTNBrO(1)sincoscossinsinOTNB(2)11,sin()tan()xyzttooo(3),(,)()tttttmmmmmxyzKinematicsxyz(4a)orsin()cos()sinsin()cossintmxmmymmmzmmmxbzlxlylz()cos()sintymmzmmylylzcos()sin()sincos()coscostmxmmymmmzmmmzbzlxlylz(4b)tm,tmand,()(,)mmmmmtttttxyzInvKinematicsxyz(5a)orcossinmxttttxlxzsinsinsincossincosmyztttttttttylbxyzcoscossinsincoscosmzztttttttttzlbxyz,mtmt(5b)(),(),(),(),()ttttttttttxxuyyuzzuuu(6)2212222222()2()llttttttkkttttttVhVhxxyyzzuuxyzxyz(7),kkkttttuutuutuudxdydzxyzdududu222222,kkkttttuutuutuudxdydzxyzdududu(8),()(,)rrrrrrrrrrmmmmmtttttRxyzInvKinematicsxyzThedesiredalgorithmsfortheproposedapproachtotoolpathgenerationandcontrolarepresentedinthefollowing.4.1CCpathinterpolation,cutteroffsetting,andinversekinematicsconversionThecorefunctionsfortheinterpolatoraretheCCpathinterpolation,thecutteroffsetting,andtheinversekinematicsconversion.LetthesplinefunctionsfortheCClocation(C)andsurfaceprinciplenormal(N)beexpressedby,cccCuxuyuzu,xyzNuNuNuNu(9)whereuisthespatialparameteralongthespline.Theinterpolationalgorithmstatedintheabovesectionisutilizedhere.BecausetheinterpolationisconductedfortheCCoutputpath,ratherthantheCLpath,thesubscripttinEqs(7)andEqs(8)needstobereplacedbyc,whichcorrespondstotheCCpath.Besides,theCLvelocity(lV)inEq.(7)needstobereplacedbytheCCvelocity(cV).ThecutteroffsettingalgorithminEqs(1)andEqs(2)isalsosuitableforreal-timecutteroffsetting.NoticethatBTNandtheunittangentvectorTalongtheCCpathcancalculatedby11kkkkdCuCuCuduTdCuCuCudu(10)CAMComputationofpracticalCCpathinterpolatoraxialcontrolleraxialdriveaxialcontrolleraxialdrivemachineandprocesscompositeCCdata(C,N,Vc,)CNCCRPFig.7.Proposedtoolgenerationandcontrolscheme.Throughthecutteroffsetting,thecutterlocationandorientationisavailable.Basedontheinversekinematicsconversion,whichisdepictedbyEq.(5c),wecangetthereferencecommandstothefiveaxialdrives,R.Inadditiontotheabovecorefunctions,twooptionalfunctionsthatincludereal-timecompensationfortheCCpathdeviationerrorandadaptationoftheCCvelocitycanbeintroducedtoaugmentthepracticalcontrolperformance.ThesetwofunctionsbasedonthefeedbackofthepracticalCCpoint,*C.4.2CalculationofpracticalCCpathIntypical5-axismachinetoolmotioncontrol,theavailablefeedbackdataaretheoutputpositionsalongthefiveaxes,whicharepmx,pmy,pmz,pmandpm.BasedonthedirectkinematicsconversionreferringtoEq.(4a)and(4b),wecangetthepracticalcutterlocation(*,LO)asComputationofpracticalCCpathinterpolatoraxialcontrolleraxialdriveaxialcontrolleraxialdrivemachineandprocesscompositeCCdata(C,N,Vc,)CNCCRP