Increasing the Operation Window for Dynamic Positioned Vessels Using the Concept of Hybrid Control

Abstract

In order to extend the operational window of marine vessels, the high-level control of the dynamic positioning (DP) system is revised. Major contributions of this paper include the modeling of a hybrid controller for a DP vessel in a varying sea state using the hybrid dynamical systems framework proposed by [1], and establishing global asymptotic stability of the closed-loop hybrid system. Simulations in a sea state varying from calm to extreme are conducted with the hybrid controller, and a single controller with adaptive wave filtering for comparison. The single controller becomes unstable in extreme seas whereas the hybrid controller shows good performance. Switching is based on spectral analysis of the vessel wave frequency motions.