Design And Research Of Ship Dynamic Positioning System Controller Based On Hybrid Control Algorithm

Ship dynamic positioning system means the all equipments on a dynamic positioning ship, mainly including power system, control system and propulsion system. In addition, the control system is the key part of the dynamic positioning system. This thesis carries out the design and research of controller in ship control system, combining with the characteristics of ship motion study, designs the hybrid control algorithm, including the classic PID, intelligent fuzzy control and decoupling control algorithm. The position and heading information after data processing,detected by ship sensors, will be subtracted with position and heading information presupposed. Their respective deviation and deviation change rate will be passed as input to the controller. With the designed hybrid control algorithm, the controller will give the corresponding thrust information to ship propulsion system. So the ship can position to the specified point intelligently.The thesis researches on the mathematical model of the ship, including the coordinate system, the transformation between the fixed coordinate and ship coordinate, building the nonlinear motion model of the three directions in the fixed coordinates, getting the corresponding motion model of the surge, sway and yaw three degrees in the ship coordinate.The thesis analyzes the function and requirements of the controller in dynamic positioning control system. Combining with the ship motion characteristics and the control advantages and application field of PID and fuzzy control algorithm, the thesis designs a suitable hybrid control algorithm(including PID algorithm, intelligent fuzzy control algorithm) and an applicable control plan. What’s more, this thesis realizes the function of the controller, gives the designing process by software in detail. Then it simulates the controller’s effect and analyzes the simulation results and controller function.Combining with the effect of the designed controller, we find the coupling influence between the sway degree and the yaw degree. So we add the decoupling control algorithm of the two degrees, give the specific realization method. The thesis simulates the decoupling control algorithm, contrasting the before with the after, analyses the controller’s improved performance with the decoupling algorithm.