Fault Grouping Bias Strategy of Thrust Allocation for Dynamic Positioning Ship

In order to solve the problem of thrust allocation when the thruster fails during the dynamic positioning (DP) operation of surface ship, this paper proposes a grouping bias thrust allocation algorithm for the thruster in failure mode. Firstly, the performance parameter representing the fault condition was introduced into the objective optimization function to refine the fault condition and its corresponding constraints; Secondly, a minimum bias algorithm was proposed to improve the algorithm, which could avoid the thrusters to enter the thrust forbidden zone due to bias operation and improves the maneuverability of the ship; Finally, a novel thrust allocation strategy in different failure mode was designed by combining with minimum bias algorithm and grouping bias algorithm, which could take different groups to bias according to the failure mode of the thrusters. The simulation results showed that the proposed improvements and strategy could make the ship operate normally with thrusters failure, and ensure that the thrusters in other groups were not affected by the failure and worked smoothly.