Parameter Sensitivity Analysis Of Rudder/Fins And Controller Optimization

Ship maneuverability is an important research subject in ship control field, and the turning motion is an important form reflects the ship's maneuverability. During the ship turning in clam water, hydrodynamic force make the ship heeling, the ship will roll with disturbance conditions,large heeling or rolling will lead to ship capsize. Reduce heeling or rolling of ship is an important way not only to improve the ship turning performance, but also to improve the ship maneuverability performance.Two aspects should be considered to optimize the performance of turning motion, on one hand the ship inherent physical structure should be studied, which is the ship parameters; on the other hand the control strategy should be concerned, which is the design of the controller.This paper will start with parameters of rudder and fin which will affect the ship's turning motion characteristic. parameter sensitivity analysis was carried out to study the effects of ship rudder fin parameters on ship turning motion, the parameters of rudder and fins was optimized to improve the inherent turning Performance .For the controller design during the turning of the ship, the rudder is generally maintained at a stationary angle, it can be achieved by control the fins with Fuzzy Neural Network to improve system turning performance. Based on the content of the task, the paper contains following works:Firstly, the mathematical model of ship motion was established. Since the research content is the effort of Ship turning motion due to the structural parameters,so choose a clear physical meaning and can be separate analysis of each part which means separation modeling, the establishment of four degrees of freedom equations of motion is obtained by simplifying the six degrees of freedom equations, which based on the Newton's law of motion. In order to make the mathematical model more accurate, selecting the modal which testing tank and the hydrodynamic force derivatives is known,and on this basis,environmental disturbance model,the rudder and fins control model and environmental disturbance model was joined, each part of the mathematical model to represent the four degrees of freedom in the form of forces and moments. In the process of establishing the rudder model, the influence of the rudder propeller should be considered, and the effective rate and the effective angle of attack should be considered too.Secondly, build Simulink simulation model on the basis of the mathematical model.Making process of analysis the turning motion combined with the method of sensitivity analysis. Then perform turning motion simulation and analysis sensitivity for single parameter,the following results are obtained: the parameters of fins and rudder can influence the size and direction of the performance of the turning motion.Thirdly, with the help of Isight software and NCGA, two or all parameters of rudder and fin was optimized at the same time, the law of various parameters combination was obtained. Then the simulation which include optimize the fin rudder parameters or not was carried out to prove that the method is feasible.Finally, on the basis of the simulation model, the PID controller and Fuzzy Neural Network controller for the fins was designed. By making comparison with different parameters or controller, the conclusion was obtained that the performance of the turning motion better with the Fuzzy Neural Network controller than the PID controller.By optimizing the parameters of rudder and fins can not only improve ship heeling in clam water, but also have equally effective to reduce rolling after join disturbance. The parameter of rudder and fins optimization combine with fuzzy neural control method can achieve the better control effect, furthermore, improve the performance of ship turning .