Error-driven-based adaptive nonlinear feedback control of course-keeping for ships

This paper presents a robust adaptive nonlinear feedback algorithm based on error-driven function for ships course-keeping which are subjected to the unknown time-varying disturbances, uncertain ship model parameters and control saturation. Nonlinear feedback and adaptive techniques are used to design the control law. The error-driven function is designed to avoid the input saturation and adjust the control gain. The designed adaptive law not only achieves the self-regulation of course-keeping control system but also adjusts parameters adaptively. In addition, the Lyapunov direct method is utilized to analyze the stability of course-keeping system. Theoretical analysis indicates that the designed control law can achieve the ship course-keeping while ensuring that all signals are bound. Finally, the effectiveness of the developed control strategy is demonstrated by simulations and comparative results.