ninFig..Thecomputationalresultsshowedthatthedeflectionduetoitsownweightwasnegligible.WhenaNforcewaslocatedatthemachiningpositioninz-direction,thenumericalresultsshowedthatthedisplacementchangeattheworktablewouldbeabout..,andthebackfamewouldundergolessthan..deflectioninz-direction.Itseemsthatthe-axismillingmachinehasgoodstiffnessduetogoodframedesignandapairofsmallLMguidessupportingeachx-andy-direction.Themodalanalysisrevealedmanyimportantdynamicmodesofthe-axismillingmachine.Weusedtheimpacthammertesttoverifythecomputednaturalfrequencies.Themeasurednaturalfrequenciesdonotexactlymatchthecomputedones,buttheindicatedfrequencyrangefromthefiniteelementmodalanalysiswassimilartothatfromtheimpacthammertest.Fig.andTableshowthemeasurednaturalfrequenciesandcorrespondingfrequencyresponsefunctionofthe-axismillingmachine.Itcanbeseenthatthenaturalfrequencieso器,将会放入H∞控制器前得伺服回路预成型指令。
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