The Research Of The Dynamic Model And Ride Control Of Wave Piercing Catamaran

As one kind of the modern high-performance ships, wave piercing catamaran (WPC)inherits the excellent feature a variety of ship form. Because of its good rapidity, spacious deck and flexible maneuverability features, WPC is widely used in the rapid and efficient maritime transport field, such as military and passenger ferry. However, as a result of the slender strips, the longitudinal stability of the WPC is poorer, which can result in severe pitch and heave motion while operating in high sea state with high speed,and which can be a safety threat to the equipment,staff and passenger. The target of the research is to improve the comfort of the WPC by selecting appropriate devices and algorithm while navigating in high speed, the main task of this thesis is as follows:Analyzing the publications of the ride control of the high performance ship at home and abroad, comparing the characteristics, installation limits and the range of application, and then,the T-foil and trim tabs are adopted as the control foils in the paper.By defining the reference coordinate system and using the theory of rigid motion,combined with the surrounding marine environment's influence on the rigid motion, the six degrees of freedom movement model of WPC is set up. The model is decoupled by considering the slender and symmetry characteristics of the submerged hull. In this paper, a method of developing the irregular wave interference of input by superposing unit amplitude wave interference force/torque based on the input and output characteristics of the linear system is proposed.With a specific WPC as the research object, the parameter variation of the established model with the encounter frequency is analyzed and a method of determining the final parameter is proposed. The motion model is analyzed in frequency and time domain respectively, by analyzing the results, the key research sea station, operating speed and the final simulation model is determined, and then, the stability of the model is analyzed using the Lyapunov's stability criterion.In this thesis, a method of optimizing the area of the control foils according to the maximum of the wave interference is put forward. By simulating the dynamic characteristic of the T-foil and trim tabs using computational fluid dynamics method, and comparing with the wave interference, the final geometry size of the hydrofoils is determined.In the consider of all the state can be obtained in the simulation model, but in practice,the sensor signal is very complex, full state feedback and single variable feedback H infinity robust controller are designed, the results of the simulation and statistical analysis indicate that by activating the T-foil and trim tabs, the vertical motion of the WPC can be improved effectively.