Modelling of Large Ship Motion and Design of Intelligent Rudder Control Mechanism

A large ship is hard to keep and change its heading because of its large tonnage, large inertia, poor brake perfomance and poor tracing ability. According to the movement characteristic of large ship and the disturbance characteristic of the sea environment, three degree of freedom motion nonlinear mathematic model of large ship is established and a rudder control mechanism based Artificial Neural Network (ANN) algorithm is designed for the large ship for the first time. The paper describes how to use neural network model to keep the large ship in good state under changing sea environment and presents the approach of the feed forward neural network theory and Back Propagation Learning Algorithm (BP). The simulation results show that the ship motion mathematic model has good turning movement characteristic and the ship has good heading- change and heading-keeping characteristics under environment disturbances.