模糊滑模控制.ppt

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1、Fuzzyarithmeticbasedreliabilityallocationapproachduringearlydesignanddevelopment初期阶段的设计和发展中基于模糊算法的可靠度分配方法V.Sriramdas,S.K.Chaturvedi,H.Gargama1.Introduction2.Factorsbasedconventionalreliabilityallocationmethod3.Fuzzynumbersandarithmetic4.Themethodology5.Illustrativeexample6.Conclusions1.Introduc

2、tionReliabilityallocationisanimportantanditerativetaskduringthedesignanddevelopmentactivitiesofanyengineeringsystem.Itisalsodifficulttaskbecauseoftheobscuredandincompletedesigndetailsandanumberoffactorshavetoconsiderindesignprocess.Duringthedesignphaseofasystemwithaspecifiedtargetreliabilitylev

3、el,thereliabilitylevelsofthesubsystemsaffecttheoverallsystemreliability.Therefore,aproperreliabilityallocationmethodneedstobeadoptedtoallocatethetargetsystemreliabilitytoitsconstituentsubsystemsproportionately.42.FactorsbasedconventionalreliabilityallocationmethodInthisallocationmethod,thetarge

4、treliabilitybasedonthereliabilityfactorsisapportionedtosubsystemsforwhichnopredictedreliabilityvaluesareknown.TherelationshipbetweenapportionedreliabilityofithsubsystemRi（子系统可靠度）andtargetsystemreliabilityR*（总系统可靠度）isdefinedwithaweightagefactorwi.Ri=(R*)wi(1)whereweightagefactorwi（权重因子）canbeexpr

5、essedwithproportionalityfactorZi（比例因子）as：wi=Zi/∑Zi(2)52.1.Complexity（复杂度）Thecomplexityfactorvariesfromsubsystemtosubsystemwithinasystemandismeasuredintermsofnumberofactivecomponentsthatasubsystemiscomposedof.Thenumberofcomponentsinasubsystemhasadirectbearingonthereliabilityofthesubsystem.Thus,c

6、omplexityhasastrongimpactonthereliabilityallocation.Thefailurerateofthesubsystemwithhighcomplexityisgenerallygoingtobehigh.So,thefailurerateisallocatedproportionaltothecomplexityofthesubsystem.Hence,Zi∝Ki,whereKiisthecomplexityfactorfortheitssubsystem.1.Multiplefunctionalrelationshipswiththeoth

7、ergroups.2.Numberofcomponentscomprisingsubsystem.62.2.Cost（成本）Foralargesystem,thecostincrementforreliabilityimprovementisrelativelyhigh.Thedemonstrationofahighreliabilityvalueforacostlysystemmaybeextremelyuneconomical.Hence,Zi∝Coi