在航道宽度受限制的水域中，船舶会受到岸壁效应的影响，横向力与首摇力矩将发生变化，这会对船舶的航行安全产生不利的影响。鉴于此问题，本文应用现代控制理论最优控制LQR方法，对在限制水域中航行的超大型油轮KVLCC2的操纵运动进行控制研究。为便于LQR控制器的设计，采用线性状态空间形式的操纵运动方程，基于数值模拟获取的相应线性水动力系数，计算出使目标函数值最小的增益矩阵K，从而得到满足最优控制规律的时域舵角变化，实现对不同宽度水域中船舶运动的最优控制，并与极点配置控制法作比较，验证LQR控制器的优越性。结果表明，当船岸距离d/L≥1.2时，船舶基本不受岸壁效应的影响，控制幅度极小；当岸壁距离d/L=0.25时，摆舵角度将超过6°，同时船舶前进速度也将下降，下降幅度将超过前进速度的10%，岸壁效应明显。
To investigate the hydrodynamic characters of a large ship in laterally restricted water, In restricted waters, ships will be affected by bank effect, sway force and yaw moment will change, which will have adverse effects on the control of ship navigation. In this paper, the LQR optimal control theory is applied to a large oil tanker KVLCC2 to achieve control design of ship maneuvering in restricted waters. In order to permit the design of a linear quadratic (LQ) controller, the maneuvering equations of motion are cast in a linear state-space framework, and CFD numerical simulation methods are used to compute the corresponding hydrodynamic coefficients. Based on the above, the paper calculates gain matrix K to minimize cost function and obtains the time-domain rudder angle satisfying optimal control law, which achieves optimal control of ship maneuvering in restricted waters with different widths. Simulation results demonstrate the effectiveness and superiority of the LQR controller compared with traditional pole placement method under the same control parameters. The results show that when the largest non-dimensional separation distance is d/L=1.2 the ship is merely disturbed and control action is very small. And the case of d/L=0.25 sees steady rudder angles beyond 6° and also forward speed reduction is 10% of the forward speed.
2017,39(7): 73-77 收稿日期：2016-09-21
DOI：10.3404/j.issn.1672-7649.2017.07.015
分类号：U661
作者简介：邵闯(1989-),男,硕士研究生,主要从事限宽水域中船舶操纵及控制研究
参考文献：
[1] 张显库. 船舶运动控制[M]. 北京: 国防工业出版社, 2006.
[2] 王先洲. 船舶及潜艇操纵中的鲁棒控制研究[D]. 武汉: 华中科技大学, 2006.
[3] 李铁山, 杨盐生, 洪碧光, 等. 船舶航迹控制鲁棒自适应模糊设计[J]. 控制理论与应用, 2007, 24(3): 445–448.
[4] MUCHA P, MOCTAR O E. Ship-bank interaction of a large tanker and related control problems[C]// ASME 2013, International Conference on Ocean, Offshore and Arctic Engineering. 2013: V005T06A072.
[5] THOMAS B S, SCLAVOUNOS P D. Optimal-control theory applied to ship maneuvering in restricted waters[J]. Journal of Engineering Mathematics, 2007, 58(1–4): 301–315.
[6] BRYSON A E, HO Y C, SIOURIS G M. Applied optimal control: optimization, estimation, and control[M]. distributed by Halsted Press, 1975.
[7] CHILALI M, GAHINET P, APKARIAN P. Robust pole placement in LMI regions[J]. IEEE Transactions on Automatic Control, 2000, 2(12): 2257–2270.
[8] KAUTSKY J, NICHOLS N K, DOOREN P V. Robust pole assignment in linear state feedback[J]. International Journal of Control, 1985, 41(5): 1129–1155.
[9] LIU H, MA N, GU X. Maneuvering prediction of a VLCC model based on CFD simulation for PMM tests by using a circulating water channel[C]// ASME 201534th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2015.
[10] LIU H, MA N, SHAO Chuang. Numerical simulation of planar motion mechanism test and hydrodynamic derivatives of a ship in laterally restricted water [J]. Journal of Shanghai Jiao Tong University, 2016, 50(01): 115–122.
