Research On Optimization Algorithm Of The Thrust Allocation For Dynamic Positioning Systems Of The Ship

As the ocean activities from the shallow to deeper,traditional mooring technology could not meet the needs of deep-sea vessels,Dynamic Positioning technology is increasingly being applied to the ship.Dynamic Positioning is that the ships automatically use its own various types of sensors to detect the deviation between the actual location and the target location and influence of the external environmental forces,such as wind,waves and ocean current etc.Under the action of the controller,ship's thrust system generates corresponding lateral force,longitudinal force and rotational torque to offset the outside interference,keeping the ship at required position of sea level as much as possible to keep positioning.The thrust allocation unit can allocate the force and moment to each propeller reasonably.The research object in this paper is"Offshore Oil***",which ship have a complex propulsion system,can working under the variety of modes.The main research of this paper is at the dynamic positioning mode.Firstly,the mathematical model of the ship motion,including the mathematical model of the ship,wind,wave,current and other environmental load model mathematical model of propulsion system is given in order to simulate and calculate.According to the propeller characteristics,combining with practical problems,present the optimization objective function and constraints.Secondly,particle swarm optimization and genetic algorithm optimization are introduced,according to the particle swarm optimization is easily to fall into local optimum and the advantage of genetic algorithm,particle swarm optimization based on genetic algorithm was designed and tested by the reference function,the results show that the hybrid algorithm have a good performance.Finally,the thrust distribution simulation model of ship Dynamic Positioning Systems is built in the MATLAB/Simulink.Under the condition of the different marine environments,particle swarm optimization and hybrid optimization algorithm are compared and analyzed,the results show that hybrid optimization algorithm can effectively complete the controller axial thrust allocation instruction with the less energy consumption,and researched the effects of different algorithm parameters for optimal results.