Current Feed Forward Control in Dynamic Positioning

The presented research investigates to what extent current feed forward control improves the positioning performance of Dynamically Positioned (DP) Floating Production Storage and Offloading (FPSO) vessels in varying currents. Positioning performance refers to the accuracy of positioning (both heading and horizontal position) and the associated power usage. Tidal current reversals and so called ‘internal soliton’ currents are examples of varying currents, in which current feed forward control is expected to improve positioning performance. Time domain simulations are carried out using the DpSim software, as developed by the Maritime Research Institute Netherlands (MARIN). In this research project, the DpSim software is extended with a module containing current feed forward control. When current feed forward control is applied in DP in varying currents, the mean and standard deviation of the control point excursion are reduced. The heading performance and power usage do not change significantly while achieving this reduction.