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.