Astheexplorationandexploitationofoilandgasproliferatethroughoutdeepwaterarea,therequirementsonthereliabilityofdynamicpositioningsystembecomeincreasinglystringent.Thecontrolobjectiveensuringsafetyoperationatdeepwaterwillnotbemetbyasinglecontrollerfordynamicpositioning.Inordertoincreasetheavailabilityandreliabilityofdynamicpositioningcontrolsystem,thetripleredundancyhardwareandsoftwarecontrolarchitecturesweredesignedanddevelopedaccordingtothesafespecificationsofDP-3classificationnotationfordynamicallypositionedshipsandrigs.Thehardwareredundantconfigurationtakestheformoftriple-redundanthotstandbyconfigurationincludingthreeidenticaloperatorstationsandthreereal-timecontrolcomputerswhichconnecteachotherthroughdualnetworks.Thefunctionofmotioncontrolandredundancymanagementofcontrolcomputerswereimplementedbysoftwareonthereal-timeoperatingsystemVxWorks.Thesoftwarerealizationoftaskloosesynchronization,majorityvotingandfaultdetectionwerepresentedindetails.Ahierarchicalsoftwarearchitecturewasplanedduringthedevelopmentofsoftware,consistingofapplicationlayer,real-timelayerandphysicallayer.ThebehavioroftheDP-3dynamicpositioningcontrolsystemwasmodeledbyaMarkovmodeltoanalyzeitsreliability.Theeffectsofvariationinparametersonthereliabilitymeasureswereinvestigated.Thetimedomaindynamicsimulationwascarriedoutonadeepwaterdrillingrigtoprovethefeasibilityoftheproposedcontrolarchitecture.
