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Mathematical Problems in Engineering
Volume 2015, Article ID 183705, 12 pages
Research Article

A Thrust Allocation Method for Efficient Dynamic Positioning of a Semisubmersible Drilling Rig Based on the Hybrid Optimization Algorithm

1Department of Naval Architecture and Ocean Engineering, Seoul National University, Seoul 08826, Republic of Korea
2Department of Naval Architecture and Ocean Engineering, Research Institute of Marine System Engineering, Seoul National University, Seoul 08826, Republic of Korea

Received 7 April 2015; Revised 3 August 2015; Accepted 5 August 2015

Academic Editor: Chunlin Chen

Copyright © 2015 Luman Zhao and Myung-Il Roh. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A thrust allocation method was proposed based on a hybrid optimization algorithm to efficiently and dynamically position a semisubmersible drilling rig. That is, the thrust allocation was optimized to produce the generalized forces and moment required while at the same time minimizing the total power consumption under the premise that forbidden zones should be taken into account. An optimization problem was mathematically formulated to provide the optimal thrust allocation by introducing the corresponding design variables, objective function, and constraints. A hybrid optimization algorithm consisting of a genetic algorithm and a sequential quadratic programming (SQP) algorithm was selected and used to solve this problem. The proposed method was evaluated by applying it to a thrust allocation problem for a semisubmersible drilling rig. The results indicate that the proposed method can be used as part of a cost-effective strategy for thrust allocation of the rig.