Mooring system diagnosis and structural reliability control for position moored vessels

Abstract

Early diagnosis and fault-tolerant control are essential for safe operation of floating platforms where mooring systems maintain vessel position and must withstand environmental loads. This paper considers two critical faults, line breakage and loss of a buoyancy element and employs vector statistical change detection for timely diagnosis of faults. Diagnosis design is scrutinized and a procedure is proposed based on specified false alarm probability and estimation of the distribution of the test statistics on which change detection is based. A structural reliability index is applied for monitoring the safety level of each mooring line and, a set-point chasing algorithm accommodates the effects of line failure, as an integral part of the reliabilitybased set-point chasing control algorithm. The feasibility of the diagnosis and of the fault-tolerant control strategy is verified in model basin tests.

Incident detection and isolation in drilling using analytical redundancy relations

“…The inverse cumulative distribution can be used to determine the threshold h as a function of the probability of false alarms P FA , even if the residuals are not independent and identically distributed [39,40,41]. The threshold is then given by…”

Real-time detection of transverse stability changes in fishing vessels

“…Statistical change detection has proven to be a successful methodology for the design of condition monitoring systems whenever timely decision under uncertainty and robustness are paramount. Examples of such systems are offered by Galeazzi et al (2013Galeazzi et al ( , 2015 for the real-time monitoring of parametric roll resonance on merchant vessels; Fang et al (2015) for the timely detection of faults in mooring systems of offshore floating platforms; Willersrud et al (2015) for the robust detection of drillstring washouts during drilling operation for oil and gas; Hansen and Blanke (2014) for the real-time detection of airspeed sensor faults in unmanned aerial vehicles; Ghane et al (2018) for wear detection in the downwind main shaft bearing of a spar-type floating wind turbine; Pradhan and Gupta (2017) for the detection of incoming vessels by measuring the ambient noise to enhance security of port and offshore operations.…”

Advanced control for fault-tolerant dynamic positioning of an offshore supply vessel

“…Single point thruster failures in DP applications are extensively described in Phillips (1998) and early diagnosis and fault-tolerant control for safe operation of floating platforms where mooring systems maintain vessel position and must withstand environmental loads are considered in Fang et al (2015). Systematic fault-tolerant control was studied for the station keeping of a marine vessel by Blanke (2005) and a structure-graph approach for fault diagnosis and control reconfiguration was validated by sea tests.…”