Robust control of ship fin stabilizers subject to disturbances and constraints

This paper is concerned with constrained roll control of ship fin stabilizers operating in wave fields. Our approach is based on a robust control algorithm for linear discrete-time systems subject to bounded additive disturbances and a general class of input-state constraints. The proposed method is applied to control of fin stabilizers. Simulation results show that the proposed robust control method reduces the ship roll motion while satisfying the input and dynamic stall constraints. The proposed control algorithm does not involve on-line optimization, except for a linear program solved at initialization. On the theory side, we present a generalized form of our robust constrained control algorithm to the case of mixed state-input constraints.