Ship Lateral Motion Parameter Identification Method Based On Multi-objective Swarm Intelligence

In the field of ship control,ship motion model can be used to build the ship maneuvering simulator and provide the basic simulation platform for the study of closed-loop system,and applied directly to design a ship motion controller.The hydrodynamic coefficient is one of the important parameters of ship motion model,and to obtain ship hydrodynamic coefficients by theory or experiment cannot guarantee the accuracy.As a result,now the system identification methods are adopted to estimate hydrodynamic parameters.It has been proved by practice that hydrodynamic parameter identification can be considered as an optimal search problem.It has been proved that hydrodynamic parameter identification can be considered as an optimal search problem.this paper mainly focuses on multi-objective particle swarm optimization and its application in hydrodynamic parameter identification in lateral motion of ship.Firstly,the model of ship lateral motion is set up.And then the paper introduce the basic theory of the multi-objective optimization problem And it is analysed that ship lateral motion parameter identification problem can be converted into a nonlinear optimization problem and can be a multi-objective optimization problem.Secondly,the paper briefly introduces the basic principle of particle swarm optimization algorithm and the work flow and then expounds the concept of the common multi-objective particle swarm optimization algorithm,including the evaluation standard of particles,the saving of external reserve set and the selection of the global optimal solution and the local optimal solution.the paper introduces the performance metrics of multi-objective optimization algorithm.And the paper introduces the main strategies of particle swarm optimization based on competition mechanism.Based on the competition mechanism of CSO,the paper puts forward the multi-objective optimization algorithm based on competition mechanism and explain respectively the external reserves set and the global guide selection.it is concluded that the multi-objective optimization algorithm based on competition mechanism have the good convergence performance to the common multi-objective optimization problems.Thirdly,the paper proposes a ship lateral motion parameter identification method based on improved multi-objective particle swarm optimization.The model of wave disturbance is designed as the input parameters of the identification,and the three target functions of the identification problem are determined.The proposed method is used to identify ship lateral motion parameters.The experiments show that the proposed method can obtain many non inferior solutions of parameter identification of ship lateral motion,and the error betweentarget value corresponding to these non inferior solutions and actual observation value is small,so the decision makers can make choice according to the actual need,which has better practical significance.