Study on Thrust Allocation Logic of DP System
|School||Shanghai Jiaotong University|
|Course||Design and manufacture of ships and marine structures|
|Keywords||Dynamic Positioning System Thrust Allocation Logic Optimizing model Singular Configuration Non-convex problem|
As the executive body of DP system, the propellers receive the thrust commands generated by the thrust allocation logic(TAL) and act correspondingly to keep the vessel in the set point. The hydrodynamic character varies from thrusters of different type, leading to the variety of the TAL. A good quality TAL would dramatically cut the cost of DP system, for that the TAL undertakes the task of reducing the power consumed by DPS. However, a good quality TAL does not have the only objective to reduce the consumed power, but also have some other factors taken into consideration, for example, to safeguard the maneuverability and to bring down wear and tear. How to design a good quality TAL would be discussed in this paper. And the work done in this paper is just some part of it. Firstly, a perfect TAL mathematical model is attempting to be constructed, based on the accurate objective function model and integrated constrained condition model. Secondly, starting from the singular configuration phenomenon, the author elaborates on how the singular configuration comes about comprehensively and deeply, and proposals a method to avoid it, which will be proved efficient by the numerical calculation. Finally, study on the non-convex problem is carried out,which needs to be paid much more attention on in the future.