Adaptive neural path-following control for underactuated ships in fields of marine practice

In this note, one concerns with the problem of robust adaptive path-following control for uncertain underactuated ships in fields of marine practice: waypoints based navigation. A novel "logical virtual ship (LVS)" based steering law is developed to programme the rational reference route, which is to guidance the underactuated ship in the practical engineering. Furthermore, a practical adaptive neural control algorithm is proposed by virtue of the dynamic surface control (DSC) technique, neural networks approximation and polar coordinates scheme. And much effort are made to obtain semi-global uniform ultimate bounded stability for the closed-loop control system, using the Lyapunov synthesis. The advantages of the developed control scheme are that first, it could tackle the practical condition "waypoints based navigation", which is very meaningful for applying the existed theoretical algorithm in control engineering; second, the developed neural controller is able to capture the vehicle uncertainties without the exact information of hydrodynamic damping structure and the sea disturbances. These characteristics would facilitate the implementation of the algorithm in the marine practice. Two numerical examples have been given to illustrate the performance and effectiveness of the proposed scheme. (C) 2015 Elsevier Ltd. All rights reserved.