Marine Cybernetics Vessel CS Saucer: - Design, construction and control
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- Institutt for marin teknikk 
This thesis presents the design, construction and control systems developmentof the marine cybernetics vessel CS Saucer. CS Saucer is a fully actuatedand highly controllable vessel with a spherically shaped hull, much likea flying saucer. The vessel is fitted with three azimuth thrusters which aredriven by three Torpedo 800 motors. The embedded controller myRIO fromNational Instruments is used to control the vessel. The system is poweredby a three cell 11.1V Lithium Polymer battery. The hull of the vessel is constructed from three millimeter MDF sheeting,milled Divinycell foam and a woven carbon sheet fitted to the exterior ofthe vessel with epoxy. This results in a rigid and watertight hull with a lowdraft. The vessel has a detachable lid made of plexi glass that is secured tothe top of the vessel with four butterfly screws. The drag forces acting on the vessel have been analyzed through testing inthe Marine Cybernetics Laboratory (MC Lab) at NTNU. The results havebeen used to derive the parameters for a dynamic model used in Hardware-in-the-loop testing and for future model based control design. The forcesproduced by each of the thrusters have been mapped and approximated withlinear curve fitting. This approximated force mapping has been used in theimplemented thrust allocation with fixed thruster angles. Manual thruster control and manual force control of the vessel can be operatedby the application on the host computer or directly from the Dashboardapp from National Instruments available on Android and iOS devices. A dynamicpositioning system has been implemented on the CS Saucer and testedin the MC Lab. The dynamic positioning system performs as desired whenchanging the setpoint for the vessel position. A tentative path followingcontroller has also been implemented and tested on the vessel. The completed CS Saucer is a fully functioning vessel and a stable and expandableplatform for use in future demonstrations, projects and research atthe MC Lab.