Integral LOS control for path following of underactuated marine surface vessels in the presence of constant ocean currents

In this paper, we consider the development of a control strategy for path following of underactuated marine surface vessels in the presence of ocean currents. The proposed control strategy is based on a modified Line-of-Sight (LOS) guidance law with integral action and a pair of adaptive feedback controllers. Traditional LOS guidance has several nice properties and is widely used in practice for path following of marine vehicles. However, it has the drawback of being susceptible to environmental disturbances. In this work, we propose a modified LOS guidance law with integral action for counteracting environmental disturbances. Paired with a set of adaptive feedback controllers, we show that this approach guarantees global asymptotic path following of straight-line paths in the presence constant and irrotational ocean currents.