Reliability-based dynamic position control of floating vessels: a numerical and experimental study

This paper addresses dynamic positioning of surface vessels moored to the seabed via a turret-based spread mooring system, referred to as position mooring. Different options relevant for construction of automatic control schemes for the thruster system are first discussed based on consideration of relevant loss functions. In particular, the role of structural reliability criteria applied to the mooring system is addressed. A control algorithm based on such reliability criteria is introduced. The structural reliability measure becomes an intrinsic part of the controller, automatically adjusting the allowed motion limits based on current weather conditions and structural properties of the mooring lines. The performance of this control system is subsequently demonstrated both by numerical simulations and laboratory experiments on a model vessel.