Simulation Research On Ship Rolling Motion And Fin Stabilizing Control System

As a kind of mature and effective ship stabilizer, fin stabilizers have been applied on various ships more widely. Fin stabilizers play an important role in improving ship seakeeping quality, ensuring equipments in normal working conditions, making crews work comfortably, improving ship seaworthiness and so on.This thesis studies ship fin stabilizing control system, and makes further simulation research on ship rolling motion and fin stabilizing control algorithm.According to the theory of random waves, this thesis analyzes the constitution of random waves in terms of wave spectrum. By means of uniformly-space, this thesis creates the mathematical model of wave angles, and revises the model according to the actual ship's breadth and draught, creates the mathematical model of random waves and proceeds the simulation research using Matlab software.According to the feature and the analysis of ship rolling motion, this thesis creates the mathematical model of ship rolling motion. In the light of the actual parameters of ship "Yukun", the mathematical models of rolling motion at different speed are created. This thesis makes simulation research on ship rolling motion under different marine conditions and gives open loop rolling curves.This thesis discusses the theory of ship fin stabilizers and the constitution of fin stabilizing control system, analyzes the mathematical models of fin stabilizing each link and makes simulation research on ship fin stabilizing PID control system. The result of simulation indicates that PID controller is satisfactory on the whole under the certain marine conditions. Because of the complexities of shipload and the uncertainty of marine environment, this thesis designs fuzzy-I controller according to the advantage of fuzzy controller and PID controller. Simulation research is made under different marine conditions. The results indicate that this anti-rolling effect is satisfactory.According to the feature of fuzzy control, this thesis designs ship fin stabilizing fuzzy self-adjusting PID controller which can adjust PID control parameters. This controller can adjust PID parameters according to different marine conditions in order to optimize control effect, and is verified by simulation. This thesis designs ship fin stabilizing single neuron controller according to the self-study ability of neural network, and makes simulation research under different marine conditions. The result of simulation research indicates that this controller can accommodate to different marine conditions,and its anti-rolling effect is ideal relatively.