Reliability-based robust dynamic positioning for a turret-moored floating production storage and offloading vessel with unknown time-varying disturbances and input saturation

Yuanhui Wang; Yulong Tuo; Simon X Yang; Mohammad Biglarbegian; Mingyu Fu

doi:10.1016/j.isatra.2017.12.023

Reliability-based robust dynamic positioning for a turret-moored floating production storage and offloading vessel with unknown time-varying disturbances and input saturation

ISA Trans. 2018 Jul:78:66-79. doi: 10.1016/j.isatra.2017.12.023. Epub 2018 Jan 20.

Authors

Yuanhui Wang¹, Yulong Tuo², Simon X Yang³, Mohammad Biglarbegian⁴, Mingyu Fu⁵

Affiliations

¹ College of Automation, Harbin Engineering University, Harbin 150001, China. Electronic address: wangyuanhui@hrbeu.edu.cn.
² College of Automation, Harbin Engineering University, Harbin 150001, China. Electronic address: tuoyulong@hrbeu.edu.cn.
³ School of Engineering, University of Guelph, Guelph, ON N1G 2W1, Canada. Electronic address: syang@uoguelph.ca.
⁴ School of Engineering, University of Guelph, Guelph, ON N1G 2W1, Canada. Electronic address: mbiglarb@uoguelph.ca.
⁵ College of Automation, Harbin Engineering University, Harbin 150001, China. Electronic address: fumingyu@hrbeu.edu.cn.

PMID: 29370899
DOI: 10.1016/j.isatra.2017.12.023

Abstract

In this paper, we derived a mathematical model for a floating production storage and offloading (FPSO) vessel and its buoy mooring system and developed a new robust positioning controller to keep vessels in a desired region in the presence of unknown time-varying disturbances with uncertainties and input saturation. Different materials (chain and polyester) and buoys are considered in the model of mooring system to make the developed model more realistic. We employed a disturbance observer to estimate the disturbances and designed an auxiliary dynamic system integrated with the structural reliability's derivative to quantify the input saturation's influence, and its states are used to the control design. Our proposed controller can keep the structural reliability and heading at desired values with arbitrarily small errors while guaranteeing the uniform ultimate boundedness of all signals in the closed-loop control system. It is easier for the control design because disturbances and input saturation are handled simultaneously and so is the stability analysis because only one Lyapunov function is needed. Simulations are conducted to demonstrate our proposed controller's effectiveness and a comparison with a robust controller based on hyperbolic tangent functions shows our proposed controller can avoid steady errors with desired control goals.

Keywords: Disturbance observer; Input saturation; Mooring system; Robust control; Ship modeling.