Research On The Application Of Fuzzy PID Decoupling Control Method In Ship Dynamic Positioning System

Ship Dynamic Positioning System has an important significance in thedevelopment of marine. Every contury pay attention to the technology,and it isrelatively mature in the foreign country. So it has far-reaching significance toresearch on the technology for China’s marine industry. It is proposed thatresearching the fuzzy PID decoupling control algorithm on the DPS based on thethree degrees of freedom motion model.The factors that determining the ship motion of the level of surface is swing,sway, yawing. Motion of the vessel is divided into high frequency and lowfrequency motion movement. Only low frequency motion can affect the position ofthe ship. The factors which causing the low frequency of motion is including wind,first-order waves, currents and power. Establishing the model of three degrees whichis associated with damping matrix, hydrodynamic matrix and inertia matrix.Hydrodynamic coefficients and inertia coefficients are obtained after a certainsimplification. So it is impossible to get the accurate model. The classic PID controlsystem can not meet the control requirements. And fuzzy algorithm does not rely onaccurate mathematical model, and has better robustness, In this paper, taking themethold of fuzzy PID control algorithm. Establishing a position-speed controlstrategy bicyclic. There is a coupling in the transverse direction and headingdirection. Finally taking the method of diagonal decoupling in the inner loop.Calculating the correct decoupling compensator based on the mathematical model ofthe object. Achieving the single-loop control of Sway and yaw.Building the double loop control in Simulink, including the inner speed controland outer position control. Building the simulation diagram of the conventional PIDcontrol, PID decouple control and fuzzy PID decoupling Successively, debuggingthe parameters. According to the simulation results, analyzing and comparing severalalgorithms and summarizing the advantages and disadvantages. verifying the goodresults of decoupling of the fuzzy PID control, and showing the immunity of thismethod to some extent.