A switching path following controller for an underactuated marine vehicle

Building on previous work of Aicardi et al.(Aicardi et al., 2001) a path following controller for underactuated planar vehicles is designed by adopting a polar-like kinematic model of the system. The proposed solution does not generally guarantee null asymptotic path following error, but only its boundedness below an adjustable upper threshold. However, knowledge of the spatial derivative of the paths' curvature is not necessary, thus resulting in a much easier solution to implement when compared to the alternatives available in the literature. Indeed, controllers achieving perfect path following usually require not only the use of the paths' curvature, but also of its derivative with respect to the curvilinear abscissa. Furthermore, the proposed solution may be used to solve the path following problem for unicycle models as well as underactuated marine vehicle models or to master-slave coordinated maneuvering of two vehicles. Simulation results illustrate the performance of the proposed control law.