Straight-Line Trajectory Tracking Control for Sampled-Data Underactuated Ships

Straight-line trajectory tracking control of sampled-data underactuated ships with both state and output feedback controllers is considered and analyzed by resorting to a nonlinear sampled-data control theory. State feedback controllers and reduced-order observers are designed on the basis of the Euler approximate models. Then they are combined to obtain output feedback controllers that semiglobally practically uniformly asymptotically stabilize the tracking error dynamics. Both simulation and experimental results are given to show the efficiency of the designed controllers.