An Investigation of A Ship's Course Sliding-Mode Control Based on Affine Nonlinear Models

In this study, the differential equation set that describes a ship's motion was derived based on a ship's motion process and the controlling principle of a ship's course by the steering engine. By selecting a ship's trajectory, course angle and yawing angular velocity as the state variables and the rudder angle as the control input, the system can be regarded as a type of affine nonlinear system for further analysis. Using the established affine nonlinear mathematical model, single-segment and multi-segment sliding-mode surfaces were designed for solving the sliding-mode variable-structure controller. Moreover, Simulink simulation results from a MATLAB platform and experimental results of a model ship in a pool demonstrate that the sliding-mode variable-structure control theory can achieve a favorable control of the trajectory and course of nonlinear ship motion systems.