Design And Simulation Research Of Ship Dynamic Positioning Controller Based On Fuzzy Control

The ship dynamic positioning system refers to all the equipment required for the ship to automatically maintain the position(fixed position or preset trajectory)by the thrust of the propulsion system,including:the power system and the propulsion system.Control system and measurement system.The accuracy and stability of the ship's dynamic positioning system requires that the functions of each part be realized in an optimal way.The core of the control is the rationality and effectiveness of the control system,because it determines the input of thrust distribution.The first step in the normal operation of the entire system is a prerequisite for ensuring accurate and stable operation of the entire system.The research content of this paper is the research and design of the ship dynamic positioning system controller based on fuzzy control.The main work contents are as follows:Firstly,the kinematics and dynamics of the real ship model are studied in the hull coordinate system and the northeast coordinate system to establish a mathematical model of ship motion,and to study the ocean environment disturbances such as wind,wave and current to establish the marine environment disturbance mathematics.The model is built in the simulation environment of Matlab/Simulink to simulate the ship motion simulation model and the marine environment disturbance model.Secondly,the fuzzy control algorithm is theoretically studied to design the fuzzy PID controller of the ship dynamic positioning system.The controller simulation module is built in the simulation environment of Matlab/Simulink,and the simulation experiment is carried out by combining the ship motion simulation model and the marine environment disturbance model.Comparing the experimental results with the Kalman filter-based marine dynamic positioning system,it is found that the fuzzy PID controller is faster,more accurate and more stable in the positioning process than the Kalman filter-based marine dynamic positioning controller.Greater control and more dramatic control changes are also needed.Finally,considering the ship thraster thrust limit and propeller loss,combined with the model prediction algorithm,the designed fuzzy PID ship dynamic positioning controller is improved,and the simulation experiment is carried out in the simulation environment of Matlab/Simulink,and the improved control is found.The output thrust of the device is always within the thrust limit of the thruster,but the time taken to reach the desired position is slightly longer than that of the fuzzy PID ship dynamic positioning controller.