Design study of a fuzzy controller for ship roll stabilisation

The design of a fuzzy controller is discussed which uses roll and roll rate as input and fin demand as output to stabilise the roll motions of a modern warship. Owing to the nonlinear characteristics of the warship roll dynamics, it was found to be necessary for the fuzzy controller to have multiple output fuzzy-set options which are invoked at different ship speeds and rudder demands. Simulation results show that the effectiveness of the fuzzy controller is equal to, if not better than, that of a multivariable controller tested under the same conditions