Global robust and adaptive output feedback dynamic positioning of surface ships

A constructive method is presented to design a global robust and adaptive output feedback controller for dynamic positioning of surface ships under environmental disturbances. Measurements of the ship's velocities are not required for feedback. The ship's parameters are not required to be known. An adaptive observer is first designed to estimate the ship's velocities and parameters. The control is then designed based on Lyapunov's direct method to force the ship's position and orientation to globally asymptotically converge to the desired values