Adaptive feedforward control for dynamic positioning of ships

Feedforward control is used in the dynamic positioning (DP) of ships to improve the tracking of reference changes. Model mismatch between the feedforward controller and the real ship can degrade the performance. An adaptive feedforward controller is presented, which estimates model parameters. It avoids many of the problems associated with closed-loop identification by utilising square-root information filtering and ensuring that adaptation only occurs when information-rich data is available.