In-transit cargo transfer between ships

Abstract

Cargo transfer between two vessels at sea requires the ramp connection between the vessels to be as stable as possible. The complex nature of the system makes employing control methods difficult. This thesis explores two ideas for improving performance of the interconnected system. First idea examines the possibility of actuating the smaller of the vessels with fins, so as to reduce the relative movement between the two points where the ramp is connected to the ships. The second idea using the larger ship to shield the smaller one from incoming waves. It is assumed that the total disturbance is minimized at a certain angle to the waves, and an Extremum-Seeking based controller is used to find this angle. To allow ship models to change dynamically as cargo offloads, the technique of extremum seeking is extended in this thesis to allow a certain type of model uncertainties.