Research on Real-Time Calculation Method of Load Response in FPSO Soft Yoke Mooring System Based on Long and Short-Term Memory Network

Abstract Due to the complex marine environment factors such as wind and waves, FPSO (Floating Production Storage Offloading) relies on the mooring system for positioning and reducing the serious consequences when excessive hull movement happens. Therefore, the production, storage, and unloading operation of FPSO are directly affected by the safety of the mooring system. At present, installing the fiber grating strain sensor on the mooring system of FPSO is the primary way of system condition monitoring. However, the problems of sensors like dropping, deformation and short circuit reduce the reliability and increase costs in monitoring. In view of the above considerations, this paper proposes a real-time calculation method for motion response of mooring system of FPSO, basing on LSTM (Long and short-term memory) algorithm. In the case where the shipborne GPS (Global Positioning System) provides six degree of freedom, the force at the specific position on SYM (Soft Yoke Mooring) system can be directly calculated. The feasibility of the load response calculation involving the critical position like pendant-hull interface and of YOKE head in FPSO SYM system is proved by comparison with the numerical simulation, providing a new method support for gradually replacing the force sensor based mooring response acquisition method, and an economical and efficient way for the real-time calculation of the key position response in the FPSO mooring system.