Modelling, identification and adaptive control of an automatic roll reduction system for a monohull ship

The paper presents the preliminary results of the implementation of an automatic roll reduction system for a new monohull ship. In order to attenuate the roll due to the waves, two auxiliary automatically controlled wings have been proposed. These auxiliary wings, which are variably dipped into the water, introduce a moment that reduces the oscillations of the ship. Dynamic models based on experimental data of the ship, of the hydraulic actuators and of the disturbances due to the waves have been computed. Two different compensators for the roll effect have been designed. The first one was designed by using classical frequency domain techniques, whereas the second was an adaptive LQG compensator. For this last compensator adaptation has been performed by using a neural network.