船舶非线性横摇运动的负反馈控制算法.doc

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1、船舶非线性横摇运动的负反馈控制算法　　摘要：　　为描述船舶横摇运动的非线性现象，找出其横摇运动的规律，建立船舶横摇运动的非线性数学模型.借助Lyapunov指数曲线来判断船舶非线性横摇运动的混沌现象；采用负反馈算法的非线性方法来控制船舶横摇运动中的混沌现象；求出适宜的负反馈系数k的范围，减轻船舶横摇运动的非线性现象.结果表明，该方法取得了较满意的控制效果.　　关键词：　　船舶横摇运动；非线性；混沌；Lyapunov指数曲线；负反馈控制　　0Introduction　　Theresearchofnonlinearphen

2、omenaofshiprollingmotion[1]includes：variousnonlinearfactorswhenshipissailing，suchasnonlinearrestoringtorqueanddampingtorque；couplingeffectofrollingandpitching，andofrollingandheaving；establishingnonlinearrollingcouplingmathematicalmodels；stability，frequencyratio，

3、saturation，crossingandchaosphenomenaoftherootsofthecouplingequation；thefrequencyofshipcapsizingintherandomwaves[2].　　ThenonlinearresearchofshiprollingmotiondatesbacktothefamousinitiativeresearchofscholarEuler，andthen，scholarKrylovwhodevelopedthetheoryfurther.Wit

4、htheimprovementofthetechnique，domesticandoverseascholarshavemadegreatprogressesandtheyadoptedmanytheories，suchasdifferentialdynamicsystemtheory，crossingtheoryandchaostheory.Forexample，NAYFEHetal[3]adoptedFloquettheory[4]toanalyzethecrossingandchaosphenomenaofshi

5、pmotions；undertheconditionoftheknownsystemattractor，LEE[5]attemptedtoadoptthecellmappingsyntheticmethodtoanalyzetheheavingrollingcouplingsystemofattractor.Duetothelimitationofcalculation，hisresearchrangeissmall.MULKetal[6]usedthepathtrackingtechnology.Theyobtain

6、edthebifurcationsetofsixDOFnonlinearmotion，foundvariousformsofoscillationofsolutionsandworkedoutthechaosattractoroccurringinthesurrounding.BIKDASHetal[7]adoptedMelnikovanalysismethod.Takingthemaximumwavesteepnessasavariableparameter，theyresearchedthesecurityofsh

7、iprollingmotion.Theseresearchesindicatethatchaosphenomenacouldbeoneofthemostcrucialfactorsthatleadtoshippingcapsizing.　　Inthepaper，themathematicalmodelofshipnonlinearrollingmotionisbuiltup，thenonlinearmethodofthenegativefeedbackcontrolalgorithmisemployedtosolvet

8、hemodel，anddifferentnegativefeedbackcoefficientsareusedtojudgewhethershipisinthechaoticstateornot.Finally，themostappropriaterangeofthenegativefeedbackcoefficientisobt