Backstepping and input saturation based control design for ship course-keeping

Based on the Lyapunov stability theory and the backstepping technique,a direct adaptive neural network controller was proposed for ship course-keeping control in the presence of input saturation. The scheme proposed was constructed by combining backstepping technique and"minimum learning parameter"technique,so the computational burden of the algorithm could be reduced drastically and the algorithm is convenient to be implemented in applications. A stability analysis which is subject to the effect of input saturation constrains is conducted with the help of an auxiliary design system. The proposed NN based controller guarantees that all the close-loop signals are uniform ultimate bounded( UUB) and the output of system converges to a small neighborhood of the desired trajectory. Numerical simulations illustrate the effectiveness of the proposed algorithm.