| In the ship course control, there are two kinds of control problems. First, course-keeping is carried on when the change doesn't happen on setting course. Second, course follow-up is carried on when the change happens on setting course. In fact, different control strategies should be applied to the two kinds of control problems. However, in order to simplify the problems, only one control rule is used, which is not satisfied with the effect of big angle on setting course. In order to ameliorate the condition, the method of dynamic course-setting is applied to smooth the setting course. Its basic idea is that in the beginning there is a fixed value in the dynamic course-setting prior to the real course until the value tends to the course-setting generally. This method can reduce the error on dynamic course, smooth in the process of control and reduce overshooting.In the paper, nonlinear robust controller in the control system is designed in accordance with the responding nonlinear ship motion mathematical model and based on the exact feedback linearization and the closed-loop gain shaping algorithm. For the system, firstly, normal algorithm is used to set the dynamic course, and then fuzzy reasoning is applied to the change on setting course in order to improve the performance of system.The Simulink of MATLAB is used to simulate the system in this paper. In order to enhance the reliability of the simulation, the wind and wave model are added to the nonlinear system and realized by editing the S function. Aimed at various sea states, the simulation comparisons are made among the three conditions including no smoothness on setting course, normal algorithm used to set the course and fuzzy reasoning applied to the change on setting course. The output curves show that the effect of course-keeping is satisfied when the smoothness on setting course is added and the turning of big angle on setting course can be quickly, followed up. By comparing the...
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