Weather Optimal Positioning Control for Marine Surface Vessels

This paper addresses the problem of energy-efficient dynamic positioning (DP) for marine surface vessels by means of a weather optimal control scheme. Fundamental geometric relations associated with a pendulum in a force field are utilized to obtain fuel-efficient DP functionality. First, weather optimal heading control (WOHC) is achieved through the use of specific surge and yaw controllers which make a vessel behave like a force-field pendulum, employing a virtual suspension point and an associated pendulum length. This design is particularly suitable for sway-unactuated vessels. Second, an intuitive and geometrically-motivated update law is assigned to the virtual suspension point to facilitate weather optimal positioning control (WOPC), which enables a vessel to be positioned at a particular location with a weather optimal heading. Computer simulations incorporating realistic environmental disturbances are used to illustrate the performance of the suggested WOHC and WOPC systems.