Integrated control of ship roll and yaw motions

Conventionally ships are steered automatically using gyroscopic feedback of heading to compare with a demanded course, and the resultant error signal is processed by a standard three-term controller before activating the steering gear to produce a rudder deflection and correct course. Similarly independent active fin stabiliser systems are fitted, measuring roll gyroscopically and using the fins to reduce roll Significant cross coupling has been observed in this multi-variable system, and this has been used to some advantage in an active rudder roll stabilisation system. This paper describes an analogue computer study to assess the advantages of various fin control strategies, to see if significant course keeping improvements were possible, and hence to synthesise an integrated ship control system.