Dynamic positioning test for removable of ocean observation platform

A removable ocean observation platform for horizontal plane dynamic positioning test under the disturbance of ocean currents was completed successfully in the deep-water pool at Harbin Engineering University. The control system for the surge, sway, and yaw is designed according to the characteristics of the observation platform. Sigmoid (S) plane control is used to resist ocean current disturbances by the improved adaptive term. The target heading is chosen based on the theory of weather optimal positioning control (WOPC) such that when the platform maintains the target heading, the energy consumption of the propulsion system is minimal. A fixed-output time control approach is proposed for the platform heading control to avoid the effect of thruster dead zone. Then, a grouping strategy based on the analysis of the main disturbance is introduced for thrust allocation. The effectiveness of the proposed control scheme and thrust allocation method is illustrated by pool trials. Several effective suggestions are proposed for the design of dynamic positioning systems and the positioning control of the removable ocean observation platform.