A Steering Control System to Minimize Propulsion Losses of High-Speed Containerships—Part II: Controller Design

An approach to design of steering controls for high-speed containerships to minimize propulsion losses is described. It involves time domain modeling and simulation, frequency domain analysis, and control structure investigation. A design process based on the use of linear modern and classical control techniques with locally linear models to minimize propulsion losses at important design conditions on the ship’s operating envelope is discussed. An adaptive controller to provide envelope-wide control in the face of changing environmental conditions and ship characteristics is described. Results from simulations and full-scale sea tests are summarized. On the basis of these preliminary results it appears that the adaptive controller works well under different speed and weather conditions and offers the potential for a reduction in propulsion losses over an existing PID autopilot.