Neuro-Fuzzy System for Intelligent Course Control of Underactuated Conventional Ships

In general, conventional ships have mono-variable autopilot, which controls the heading of the ship affected by perturbations, in course-keeping or course-changing maneuvers. It takes into account only the yaw angle and ignores the roll movements. Intelligent control systems can be designed, considering the ship as 2 DOF underactuated system, with yaw angle and roll angle as outputs, and rudder as control input. A neuro-fuzzy system is proposed, which modifies the autopilot commands, so that roll damping effects and heading performance to be obtained simultaneously, with small rudder angle and rudder rate values. The system can be used with any conventional autopilot with slow steering machine.