Design and test of the propulsion control of the aircraft carrier “Cavour” using Real-Time Hardware in the Loop Simulation

Design and optimisation of the propulsion system is a crucial task of the ship design. In fact the behaviour of the propulsion system is a key aspect of the global behaviour of a ship, mainly if the ship is a naval vessel. Marine propulsion simulation systems can be used to predict the propulsion plant behaviour during critical situations and during normal working condition variations. Different operational speeds, acceleration, deceleration, crash stop, heavy turning and faults are some examples of transient situation that a propulsion system has to sustain without reducing the ship safety and reliability. Generally the ship has to demonstrate the ability to perform some of the above mentioned manoeuvres by sea trials, which are costly and time consuming. In this paper a rapid prototyping and testing procedure for the propulsion controller of the new Italian Aircraft Carrier “Cavour” is proposed, using real-time hardware-in-the-loop (RT HIL) simulation. The adopted approach is the following. First the propulsion control system and the propulsion system are prototyped using a simulation model for ship propulsion developed at DINAV. The performances of the ship and its control system are evaluated using non real-time simulation. Then the control system is implemented on the real hardware and tested with RT HIL simulation. RT HIL simulation consists in the real hardware controller, which interacts with the ship propulsion models (engine, shaft line, propeller, etc.) that are simulated in real-time. This technique increases the realism of the simulation, providing access to issues not usually available in software-only simulation models, making the test of the new propulsion controller fast, safe and reliable. Consequently, it let to significantly reduce the time spent to tune the control system during the ship delivery sea trials.