Design and simulation of an ice-capable DP control system

It is claimed that 13% of the world's undiscovered oil and 30% of the world's undiscovered gas is located in the Arctic, and 84% of these findings are expected to occur offshore. The Northern Sea Route and North West passage were also recorded ice free in 2009, which enables shorter transport time between Europe and Asia. As a result of the growing interest and activity in arctic regions, International Organization of Standardization (ISO) developed a new standard, ISO 19906. This standard contains requirements and specifications for offshore activities in the Arctic and cold regions, where the conditions are far more severe and challenging than for open water. As there is little experience regarding arctic dynamic positioning (DP). By analyzing towing tests, the knowledge and understanding of a DP vessel in ice, both in terms of frequency response, force magnitude and variance, has been exploited in the process of designing a broken ice model. The broken ice model was designed by accounting for the main physical dynamics, such as ice drift velocity, ice thickness, ice concentration and ice drift direction, before incorporated into the control system. Simulations of the ice-vessel interaction with and without acceleration feed-forward (AFF) indicated that the vessel performed better when AFF was used.