Controller Design And Simulation Of Dynamic Positioning System

With the rapid development of the global economy, energy shortages and environmental pollution have become a world wide problem, so exploring and developing Marine resources became the important sustainable ways for most countries. Ships and semi-submersible platforms as floating operating system is the important carrier of deep-sea assignments, the research for the vessel and platforms received more and more attention.Dynamic Positioning System (DPS) is a closed-loop control system, which maintains desired position and heading of the vessels and rigs, by counteracting the environmental forces such as wind, wave, and current, with the forces generated by thrusters. There are three parts in the DPS:sensor system, control system and thrust system. The main content of this paper is to design an ideal dynamic positioning controller for a dynamic positioning supply ship. The main work includes the following aspects:1、Around the ship dynamic positioning system in the controller design problem, a nonlinear 3 DOF mathematical model of DP system is built, after analyzing the feature of marine vessel’s kinematics and dynamics.2、Basic principles for ADRC technology is presented, as well as structure of ADRC and discrete algorithm, then a brief discussion of parameter adjustment of every part is made for ADRC.3、ADRC which applies to the three degrees of freedom dynamic positioning system is designed. Then simulation and comparison with classical PID controllers under ideal sea conditions and different levels of sea conditions with certain wind, wave and flow separately are made.4、Particle swarm optimization algorithm, adaptive weight particle swarm optimization algorithm and its characteristics are introduced. On this basis, in order to further improve controller performance, adaptive weight particle swarm optimization algorithm for ADRC parameters optimization is used. Then simulation on parameter optimized ADRC under ideal sea conditions are made. A large number of simulation results show that:the ADRC has good controlling effect. It can reject the disturbances of certain wind, wave and flow. The control performance and robustness of ADRC are better than the traditional PID controller. The simulation study also verify the feasibility of the ADRC based on AWPSO algorithm optimization design method, It can greatly improve the control performance of the system.