Robust fin control for ship roll stabilization based on L2-gain design

A robust fin controller based on L2 gain design is proposed, in order to reduce the roll motion of surface ships. The plant consists of the ship roll dynamics and that of the fin actuator. The uncertainties including the modelling errors and the environmental disturbances induced by waves are considered in the cascaded roll system. A state feedback control is adopted to compensate the modelling errors and the derivative of desired fin angle. The disturbance is suppressed by L2 gain design. The Lyapunov function is employed in the controller design, which guarantees the stability of the fin stabilizer. Simulation results are reported and the superior performance of the fin controller with L2-gain design is illustrated when compared to a PD controller.