Improved Generalized-Inverse-based Thrust Allocation for Dynamic Positioning Vessels with Rotatable Thrusters and Force Constraint

Thrust allocation is a challenging problem for dynamic positioning vessels, especially when considering rotatable thrusters and various constraints. This paper improves the generalized-inverse-based thrust allocation. A group of configurations are selected for rotatable thrusters by examining the singularity value of the thrust configuration matrix. A a cost function is designed. And the configuration with lowest cost will be chosen as desired. Then generalized-inverse-based thrust allocation is performed on the desired configuration, and results the thrust and azimuth angles for the thrusters. Comparing with the sequential-quadratic-programming-based thrust allocation method, the proposed method is significantly faster and easy to implement. Their accuracy of the allocation is similar. The proposed method is suboptimal in the power consumption.