DESIGNANDIMPLEMENTATIONOFGUSTRESPONSEReceiveddate:2003-06-23;revisionreceiveddate:2003-10-15ALLEVIATIONCONTROLSYSTEMFORHELICOPTERSGONGHua2jun,YANGYi2dong(CollegeofAutomationEngineering,NUAA29YudaoStreet,Nanjing,210016,P.R.China)Abstract:Gustresponsealleviationisveryimportantforhelicopterswhichhavestrongcouplingandvibration.Gustdisturbancenotonlyinfluencestheridequalityandtheprecisionoftheweapondelivery,butalsoaffectstothestructuralfatigueloadandthestrength.Themethodofanoptimalcontrollawtosuppressthegustdisturbanceforhelicoptersispresented.Theoptimizationrequirestheminimizationoftheverticaloverloadatthepilot′sseat,theattitudevariationandthecontrolenergyconsumptionunderthegustdisturbance.Basedontheoriginalcontrolsystem,thenewsystemcanbeeasilyrealizedbyaddingaverticalspeedfeedbackpassage.Inordertodevelopthereal2timeoperationalflightcontrolsystem,theoptimizedcontrollawiswritteninClanguage.Thehybridsimulationsprovethattheperformanceofgustresponsealleviationandtheefficiencyofdigitalizationaresatisfactory.Keywords:helicopter;gustresponse;optimalcontrol;flightcontrolCLCnumber:V24911Documentcode:AArticleID:100521120(2004)0120013205INTRODUCTIONInordertomeettheneedsincombatmissionsandimprovethesurvivability,helicoptersgenerallyflyatverylowaltitudeswherestrongatmosphericdisturbancesexist.Thegustdisturbancewillaggregatethevibrationofhelicopterswhichareunstableintrinsicallyinlowaltitudesandpoorintheridequality.Italsomakeshelicoptersofstrongcouplingdifficulttocontrolandcutsdowntheprecisionoftheweapondelivery.From1974,thecontrolfieldofhilicoptersputforwardmanytheoriesbasedontheactivecontrolandtheelectricfeedbackofrotorvariablestosuppressthegustresponse[1,2],becausetherotorofahelicopteristhemostsensitivecomponenttothegustdisturbance.AzumaandSaitofromTokyoUniversitystudiedrotorgustresponsesbymeansofthelocalmomentumtheory(LMT)[3].BirandChopraresearchedthegustresponseofthehingelesshelicopterrotorincruisingflight[4].However,thegustresponseofthehelicopterrotorisacomplexdynamicphenomenon.Itisverydifficulttomeasurerotorvariablesdirectlytorealizetheelectricfeedback.Thispaperpresentsamethodofmeasuringflightstatevariablessoastokeeptheattitudesconstantasfaraspossible.Moreover,theridequalityrequirestheminimizationoftheaccelerationoverloadatthepilot′sseat.Consideringboththeattitudeandtheoverload,weavoidthedefectsofaccountingthestabilizationoftheattitudebutneglectingtheimprovementofridequalityandviceversaintheresearchofthegustresponsealleviation.Inordertorealizethedigitalizationoftheflightcontrolsystem,theoptimizedcontrollawiswritteninClanguage.Itisprovedbyhybridsimulationthatthemethodsforoptimizingcontrollawanddigitizingareallfeasible.Mar.2004TransactionsofNanjingUniversityofAeronautics&AstronauticsVol.21No.11MOTIONEQUATIONOFHE-LICOPTERUNDERVER-TICALGUSTDISTURBANCEInfluencesoftheverticalgustWverintheshort2periodmotionofhelicoptersarediscussedinthispaper.Assumethatahelicopterisinlevelflightwiththebodyaxisclosetoahorizontalline,andthedirectionoftheverticalgustcoincidentwiththeverticalaxisofthehelicopter.Supposingthattheupwardverticalgustispositive,wehavethefollowingshort2periodsmallperturbationequationdefinedintheleft2handcoordinatesystem[5].(FZvαZS-FZvZ)∃vZ-FZΗ∃Η+FZΗ�∃Η�=FZWY∃WY+FZvZWver(MYvαZS-MYvZ)∃vz-MYΗ∃Η+(MYΗ¨S+MYΗ�)∃Η�=MZWY∃WY+MYvZWver(1)whereSisthedifferentialoperator...
