Fault Monitooring and Fault Recovery Control for Position Moored Tanker

This paper addresses fault tolerant control for position mooring of a shuttle tanker operating in the North Sea. A complete framework for fault diagnosis is presented but the loss of a sub-sea mooring line buoyancy element is given particular attention, since this fault could lead to line breakage and risky abortion of an oil-loading operation. With signicant drift forces from waves, non-Gaussian elements dominate in residuals and fault diagnosis need be designed using dedicated change detection for the type of distribution encountered. In addition to dedicated diagnosis, an optimal position algorithm is proposed to accommodate buoyancy element failure and keep the mooring system in a safe state. Detection properties and fault-tolerant control are demonstrated by high delity simulations