Propulsion control strategies for ship emergency manoeuvres

Abstract

This work deals with the propulsion control aspects relating to some of the most critical emergency manoeuvres of a ship: slam start and crash stop. In these particular situations a very important role is played by the automation system that has to manage the whole propulsive chain (i.e. main engine, mechanical transmission and propeller) in a safe and efficient way. With regard to this, a simulation based design methodology is adopted to develop and test new control schemes for ship propulsion. The proposed control layout is applicable to any type of propulsion systems equipped with controllable pitch propellers, since it is mainly based on the automatic adjustment of the propeller pitch. Thus the desired performance requirements are met through adaptive control strategies able to address the complex issues of slam start, crash stop and similar stressful manoeuvres. The adaptivity of the automation process to several critical propulsive conditions reduces significantly the number of the control parameters to be estimated, as recently demonstrated by the automation design of a new twin-screw ship. For this application, the comparison between simulation results and sea trials data is finally shown for validation design purposes.