Afullycoupled6-degree-of-freedomnonlineardynamicmodelispresentedtoanalyzethedynamicresponseofasemi-submersibleplatformwhichisequippedwiththedynamicpositioning(DP)system.Inthecontrolforcedesign,adynamicmodelofreferencelineardriftfrequencyinthehorizontalplaneisintroduced.Thedynamicsurfacecontrol(DSC)isusedtodesignacontrolstrategyfortheDP.Comparedwiththetraditionalback-steppingmethods,thedynamicsurfacecontrolcombinedwithradialbasisfunction(RBF)neuralnetworks(NNs)canavoiddifferentiatingintermediatevariablesrepeatedlyineverydesignstepduetotheintroductionofafirstorderfilter.LowfrequencymotionsobtainedfromtotalmotionsbyalowpassfilterarechosentobetheinputsfortheRBFNNswhichareusedtoapproximatethelowfrequencywaveforce.Consideringthepropellers’wearandtear,theeffectoffilteringfrequenciesforthecontrolforceisdiscussed.Basedonpowerconsumptionsandpositioningrequirements,theNNcentersaredetermined.Moreover,theRBFNNsusedtoapproximatethetotalwaveforcearebuilttomonitorthedisturbances.WiththeDPassistance,theresultsoffullycoupleddynamicresponsesimulationsaregiventoillustratetheeffectivenessoftheproposedcontrolstrategy.
