Design of a sliding mode controller for trajectory tracking problem of marine vessels

Trajectory tracking is an issue of vital practical importance for manoeuvreing of marine vessels. Because of the nonlinearities of kinematics and dynamics of motion, conventional control designs, based on the assumption that the kinematics and dynamics can be linearised, are not competent for tracking application of marine vessels. A multivariable sliding mode control law is proposed for the trajectory tracking problem on the basis of nonlinear horizontal motion dynamics of a class of marine vessels, in which three degrees of freedom are concerned. Ship positions and yaw angle are simultaneously tracked. Lyapunov theory is used to prove the stability of the proposed control law. Simulation results show the validity of this method for ship trajectory tracking problem.