|Reliability-based Event Driven Backstepping Positioning Control for a Turret-moored FPSO Vessel with Unknown Slow Time-varying Disturbances
Yulong Tuo*, Shasha Wang*, Chen Guo*, Haomiao Yu, and Zhipeng Shen
International Journal of Control, Automation, and Systems, vol. 20, no. 2, pp.472-482, 2022
Abstract : In this paper, an event driven backstepping positioning controller based on the structural reliability is developed for a turret-moored floating production storage and offloading (FPSO) vessel with unknown slow timevarying disturbances. The mathematical model of the FPSO vessel is given at first. Secondly, to make full use of the positioning capability of mooring system while ensuring the safety of mooring lines, a continuous backstepping positioning controller is designed based on the structural reliability of the mooring system; in the meanwhile, a disturbance observer is designed to handle the unknown disturbances. Then, the proposed event driven positioning controller is achieved based on the designed continuous controller by designing suitable event driven conditions, which can determine the updated time instants of the event driven positioning controller. The proposed positioning controller can not only guarantee the uniform ultimate boundness of the errors for structural reliability and heading but also ensure that no Zeno behavior occurs. Finally, the simulations demonstrate that the proposed event driven positioning controller’s performance while reducing the execution times of FPSO vessel’s actuators.
Backstepping control, event driven control, FPSO vessel, positioning control, structural reliability of mooring system.