Roll reduction non-linear controller based on rudder and fin joint for ship

This study focuses on mitigating ship roll, which significantly impacts navigation. The research investigates a design method for a rudder and fin joint roll reduction controller based on non-linear feedback. A comprehensive 4-DOF motion model of the ship is developed. The controller aims to enhance roll stability by effectively regulating the anti-rolling forces generated by the rudder and fin. Employing a PID controller with time-varying gains enhances the system's dynamic response and enables it to withstand diverse wave conditions. Non-linear feedback techniques are implemented to minimise control variable outputs, thereby preventing excessive roll reduction forces that might lead to reverse roll. Simulation experiments are conducted to evaluate the roll suppression capability of the proposed controller. The obtained results demonstrate that the non-linear feedback-based roll reduction controller achieves outstanding roll stabilisation efficiency, reduced fin angle and rudder angle outputs, and improved heading stability when compared to conventional PID controllers.