Hybrid Control to Improve Transient Response of Integral Action in Dynamic Positioning of Marine Vessels∗

A hybrid control approach for integral action in the PID control law for dynamically positioned marine vessels is considered. The proposed method is essentially a resetting of the integration gain when the control performance deteriorates. The method allows for a flexible tuning, and could be useful when there are long periods of normal operating conditions, but abnormal events may occur. In that case the hybrid controller will have a low tuning in the normal regime and switch to a more aggressive tuning in the abnormal regime. Stability of the hybrid system is investigated, and a simulation case is performed.