A force allocation strategy for dynamic positioning

A force allocation strategy used in connection with dynamic positioning of ships and semi-submersibels is presented. The strategy dynamically allocates force, and in case of azimuth thrusters - force directions, to a set of thrusters. The strategy handles n thrusters (n greater than or equal to 2) in an arbitrary configuration. The decision making of the strategy is based on minimum power consumption taking into account effects of reversing thrusters, thruster/hull interaction and partly the effects of interaction between thrusters. The functions of the full allocation strategy is illustrated through a number of examples. Finally the strategy is compared with a more classical allocation strategy to show that significant reductions in energy consumption can be achieved.