Trajectory tracking control of unmanned ship based on back-stepping algorithm

For the complexity of ocean environment, the motion of ship is a very complicated movement, it´s very important to develop a suitable mathematical model to describe it quite exactly. Also the ship control system is a nonlinear, mutative and multi-variable system which poses many new problems and challenges for trajectory tracking control methods of unmanned ship. In this paper, a nonlinear mathematical model of under-actuated unmanned ships is developed. A state feedback control law of straight-line tracking control system is presented using the Lyapunov direct method and nonlinear back-stepping. Numerical simulation using Matlab/Simulink was provided to verify the validity of the proposed method.