Further Research Of Chaos Phenomenon In Ship Course Keeping

Ship is a multi-variable coupled time-varying and nonlinear complex dynamic system. The change of navigation speed or loading condition is extremely easy to cause the model perturbation. Ship chaotic motion may occur because of the wind, wave and current disturbances which exit in the navigation environment and are full of uncertainty. This kind of chaotic motion can have a negative impact on ship motion control. A main research subject in this paper is the course keeping motion of the large oil tanker and a certain type navy ship. A set of relatively complete simulation program is designed, which has been utilized to implement a large number of simulation analysis on the basis of real ship particulars, indicating extremely important theoretical reference and practical guidance significance to the study on the characteristics analysis of chaotic motion in the large oil tanker and navy ship course keeping.A set of simulation program, which applies to analyze the chaotic characteristics of ship course keeping motion, is designed in the environment of MATLAB and Visual Basic programming. This set of simulation program has been utilized to implement the chaotic characteristics verification and analysis to the previous research results. A variety of typical chaotic simulation results has been obtained, which lays the foundation of chaotic characteristics analysis on the basis of real ship particulars. The chaotic characteristics analysis of ship course keeping motion has been implemented based on the parameters of 4 large oil tankers and one navy ship. The chaotic motion model of ship course keeping motion has been refined, because of the deficiency of falling to take the role that the officer on watch plays in the closed loop of ship maneuvering into consideration. A refined chaotic model has been established after considering the characteristics of the officer on watch. The chaotic characteristics analysis of the refined chaotic model has been implemented on the basis of the parameters of the navy ship chaotic motion model, the simulation results of which are satisfactory.The simulation results indicate that some ships will exhibit chaotic motions with the disturbances of waves, when the parameters of chaotic model are properly configured. After taking the role that the officer on watch plays in the closed loop of ship maneuvering into consideration, the chaotic characteristics analysis of ship course keeping motion is implemented at the same configured parameters condition, results of which indicates that it does not change the chaotic motion state and can better describe the characteristics of ship chaotic motion.