网络控制系统的混杂控制和AQM算法研究

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1、北京交通大学硕士学位论文网络控制系统的混杂控制和AQM算法研究姓名：孟祥龙申请学位级别：硕士专业：交通信息工程及控制指导教师：尹逊和20080601ABSTRACTABSTRACT：Comparedwiththetraditionalpoint．to．pointcontrolsystems，NetworkedControlSystem(NCS)hasenormousadvantagessuchasthesharedresourcesofinformation，reducedsystemwiring，easyextendingandmaintenanceofs

2、ystem，highel"reliabilityandflexibility,andSOon．However,theproblemsofnetworkdelays，packetdropout，andmultiple—packettransmissionexist．SoithaspracticalsignificancetostudvthemodelingandcontrolofNCS．NetworkbringsagreatdealofconveniencetoOurdailylife，whiletheproblemsofnetworkthornyproble

3、minnetworkresearch，andresearchhotspotofcongestioncontr01．Theinthethesisareasfollows：emerge．Presently,networkcongestionisaActiveQueueManagement(AQM)istheworksaboutNCSandAQMthatarestudiedFirstly,someexistingproblemsofNCSareintroduced，andresearchprogressesofhybridcontrolofNCSandAQMinc

4、ongestioncontrolareexpoundedbriefly．Then，aclassmathematicalmodelofNCSisproposed．Thedoubletanksystemwithcontinuousflowrateregulationistakenasthecontrolledobiect，MixedLogiealDynamic(MLD)isappliedtomodeltheNCSwithdelayandpacketdropoutbasedonthemathematicalmodel，andpredictivecontroller

5、isdesigned．Thedoubletanksystemwithhierarchicalflowrateregulationistakenasthecontrolledobject，hierarchicalstructuremodelisusedtomodeltheNCSwithdelayandpacketdropoutbasedonthemathematicalmodel，andlimitedlookaheadcontrollerisdesigned．ThesimulationmodelofNCSisperformedbyTrueTime．Inthec

6、aseofdelayandpacketdropout．thedesignedcontrollersobtainbettercontroleffectbymeansofsimulation．Finally,theTCP／AQMmodelisstudied．AccordingtotherequirementofSmithpredictorforhighprecisionofthecontrolledobjectmodelstructure,anAQMalgorithmisproposedonthebasisofamodifiedSmithpredictortha

7、thaslowerrequirementforprecisionofthecontrolledobjectmodelstructureandbeRerrobustness．NS2simulationresultsshowthattheproposedalgorithmisbetterthanSmith．PIalgorithmincontroleffect．Consideringthebeaerfastresponsecharacteristicoftimeoptimalcontroller,andwhencontrolsystemclosestostable

8、，PIDcontrollerhasabetterco