Path-following of Underactuated Ships Using Serret–Frenet Coordinates
This chapter presents state feedback and output feedback controllers that force an underactuated surface ship to follow a predefined path under the presence of environmental disturbances induced by waves, wind, and ocean currents. The control solutions originated an observation that it is reasonable in practice to steer a vessel such that it is on the reference path and its total velocity is tangent to the path, and that the vessel’s forward speed is independently controlled by the main propulsion control system. The proposed controllers are designed using Lyapunov’s direct method, the popular backstepping technique, and the Serret–Frenet frame. The unmeasured sway and yaw velocities are estimated by introducing a novel nonlinear passive observer.
KeywordsClose Loop System State Feedback Output Feedback Environmental Disturbance Virtual Control
Unable to display preview. Download preview PDF.