基于统一模型的船舶迎浪参数横摇数值预报及其舵减摇研究

国际海事组织（IMO）正致力于第二代完整稳性规范的制定,而参数横摇一直是船舶动态完整稳性研究的热点。文章采用考虑船舶操纵性和耐波性运动耦合的统一模型对迎浪规则波下的船舶参数横摇运动进行了时域数值模拟。在时域模型中,六自由度耐波性运动辐射绕射力采用切片理论计算,并由脉冲响应函数法转化到时域。非线性回复力和入射波力采用瞬时湿表面压力积分方法计算。操纵性运动基于MMG模型,依据统一理论将操纵性与耐波性运动进行耦合计算。文中先应用简化三自由度模型对三艘集装箱船进行了参数横摇样船计算,并进行了初步的模型实验验证,依据结果对比分析了横摇惯性矩、初稳性高和方形系数对参数横摇的影响。基于统一模型分析了操纵性运动对参数横摇的影响,并进行了参数横摇舵减摇研究。     

A study on improving the course-keeping ability of a pure car carrier in windy conditions

The course-keeping ability of a pure car carrier (PCC) in windy conditions is discussed in this article. Numerical simulations of two PCCs were carried out to compare their course-keeping abilities in wind. The two PCCs had the same hull form but different types of rudder. One PCC was fitted with a semispade rudder (hereinafter, the normal rudder), whereas the other was fitted with a spade-type Schilling rudder (hereinafter, the Schilling rudder). Both PCCs were designed to a new concept for the accommodation structure and hull form above the load water line. In this new design concept, there are no sharp corners in the superstructure so as to reduce wind resistance and improve steering performance. The limits of course keeping for the two PCCs were investigated through simulations. The course-keeping abilities of the two PCCs, each with two different types of autopilot system, were also investigated in wind. To develop the numerical simulation, the hydrodynamic coefficients of the two PCCs were predicted based on the data published for a third PCC having similar principal particulars. The numerical model of the two PCCs was validated by comparing its behavior with the respective full-scale trial results. Wind resistance coefficients were predicted by combining the results of wind tunnel experiments of the object PCCs and a regression model. Numerical simulations under steady wind conditions were also carried out and the results compared with some full-scale experiments to validate the mathematical model of the PCC.     

Comparison of the mariner Schilling rudder and the mariner rudder for VLCCs in strong winds

A simulation model of a very large crude carrier (VLCC) with either a mariner type Schilling rudder or a mariner rudder was developed from captive and free-running model tests. Kijima’s regression formula was used to predict the hydrodynamic hull forces on the VLCC. To simulate full-scale maneuvering at cruising speed, the constant torque operation of the main engine was assumed. Considering the higher normal lift force and maneuverability of the mariner type Schilling rudder as compared to the mariner rudder, the size of mariner type Schilling rudder is kept smaller as compared to mariner rudder. To compare the efficiency of the two types of rudder system, maneuvering simulations at constant engine torque and course-keeping simulations at various gusting wind speeds and encounter angles were carried out. Based on the simulation results, the two rudder types were compared from the viewpoint of maneuvering and fuel efficiency in windy conditions.     

舵减摇仿真研究

本文通过建立船舶操纵运动和周期性摇荡运动的耦合数学模型，进行了舵减摇仿真研究。计算表明，只要适当选择舵角控制函数中的反馈系数，可以在合理的转舵速率和允许的航向变化幅度下取得满意的减摇效果。     

护卫舰横摇稳定舵的H∞/H2控制器的设计和比较（英文）

The roll motions of ships advancing in heavy seas have severe impacts on the safety of crews, vessels, and cargoes; thus, it must be damped. This study presents the design of a rudder roll damping autopilot by utilizing the dual extended Kalman filter(DEKF)–trained radial basis function neural networks(RBFNN) for the surface vessels. The autopilot system constitutes the roll reduction controller and the yaw motion controller implemented in parallel. After analyzing the advantages of the DEKFtrained RBFNN control method theoretically, the ship's nonlinear model with environmental disturbances was employed to verify the performance of the proposed stabilization system. Different sailing scenarios were conducted to investigate the motion responses of the ship in waves. The results demonstrate that the DEKF RBFNN–based control system is efficient and practical in reducing roll motions and following the path for the ship sailing in waves only through rudder actions.     

Roll-induced bifurcation in ship maneuvering under model uncertainty

In this paper, a mathematical model is developed for the maneuvering motion of a naval ship and bifurcations of its equilibrium are identified in roll-coupled motion. The subject ship is a high-speed surface combatant with twin-propeller twin-rudder system. Captive model tests are conducted for the ship using planar motion mechanism. Maneuvering coefficients are calculated by polynomial curve fitting of the test data. Uncertainty distribution in the coefficients is assumed same as that of the curve fitting errors. Uncertainty in the model coefficients is propagated to full-scale simulation results by the stochastic response surface method (SRSM). This method is computationally efficient as compared to standard Monte Carlo simulation technique. The SRSM uses polynomial chaos expansion of orthogonal to fit any probability distribution. Bifurcation analysis of the mathematical model is performed by varying the vertical center of gravity as the bifurcation parameter. Hopf bifurcation is identified. It is found that the bifurcations occur due to the coupling of roll motion with sway, yaw motion and rudder angle. In the presence of wind, roll angle response in bifurcation diagram is discussed.     

闭环增益成形算法在舵阻摇系统中的应用

给出了单输人多输出(SIMO)系统即被控对象为非方阵情况下的闭环增益成形控制算法。考虑到舵阻摇系统的闭环传递函数阵一定是奇异的，以及具有1个输入控制2个输出的特点，在保证其中1个输出尽量小而另1个输出跟踪输入的前提下，将闭环传递函数阵即补灵敏度函数阵设为具有一阶惯性的奇异阵，设计出鲁棒控制器。研究并建立舵阻摇系统的非线性模型，并在Matlab中通过编写S函数来实现。用设计好的控制器对非线性模型进行仿真，运用Simulink工具箱得到仿真曲线，从仿真曲线可看出此控制器具有良好的鲁棒性能。通过分析并比较组摇前和组摇后的各组仿真曲线，算出减摇率在50%左右，减摇效果较好。     

遥控自航船模舵减摇试验研究

本文报导用遥控自航船模在纯横浪条件下进行的舵减摇试验研究。     

潜艇深度终端滑模控制技术

潜艇垂直面运动因其强非线性、强耦合性,易干扰等因素的影响,对控制设计要求非常高.基于潜艇垂直面非线性模型,考虑舵的动态响应,用首舵控制深度,尾舵控制纵倾角,分别设计了终端滑模面,采用终端趋近律设计控制器并进行仿真研究.仿真结果表明,该系统具有良好的控制性能和很强的鲁棒性.由于采用连续的控制器,解决了系统的抖振问题.     

A proposal for propulsion performance prediction of a single-propeller twin-rudder ship

The influence of a rudder’s axial force on the prediction of full-scale powering performance of a ship is investigated in this paper. Axial force characteristics of different rudder types were investigated by open water experiments. Viscous scale effects on the rudder’s axial force were investigated by carrying out open water experiments with different sizes of rudder. Experiments were carried out in the towing tank for a model ship fitted with different rudder systems to investigate the influence of rudder’s axial force on full-scale propulsion performance prediction. Based on the experiment results, a new prediction method is proposed for estimating full-scale power that considers scale effect on rudder’s axial force. Good performance of the proposed prediction method is demonstrated by estimating the engine power of a ship installed with a special high lift twin-rudder system from model experiments and comparing it with the values measured on the ship during full-scale experiments.     

基于神经网络的鲁棒自适应舵减摇控制

针对欠驱动船舶在未知海浪扰动下的舵减摇控制问题,设计一种基于有限时间收敛的滤波反步滑模自适应控制器。

首先,针对常规反步法中微分爆炸问题,引入一阶滤波器,以避免对虚拟控制律的求导;然后,根据有限时间控制理论,通过滤波反步法与滑模自适应控制方法,设计有限时间收敛的舵减摇控制律;最后,通过李雅普诺夫稳定性理论,证明航向子系统和减摇子系统的稳定性。

仿真结果表明,在不同海浪扰动下,所设计控制器使船舶能够在有限时间内追踪航向并实现减摇效果;与反步滑模控制相比,所设计控制器可改善船舶航向保持控制性能,减摇率提升了5%。

所提方法可为欠驱动船舶舵减摇控制问题提供参考。

     

Non-intrusive polynomial chaos for efficient uncertainty analysis in parametric roll simulations

Monte Carlo analyses are generally considered the standard for uncertainty analysis. While accurate, these analyses can be expensive computationally. Recently, polynomial chaos has been proposed as an alternative approach to the estimation of uncertainty distributions (Hosder et al. A non-intrusive polynomial chaos method for uncertainty propagation in CFD simulations. In: 44th AIAA aerospace sciences meeting and exhibit, Reno, Nevada, 2006; Wu et al. Uncertainty analysis for parametric roll using non-intrusive polynomial chaos. In: Proceedings of the 12th international ship stability workshop, Washington, DC, USA, 2011). This approach works by representing the function as a series of orthogonal polynomials; the weights for which can be calculated via several methods. Previous studies have demonstrated the usefulness of this technique for comparatively simple systems such as parametric roll modeled by the Mathieu equation with normally distributed parameter values (Wu et al. Uncertainty analysis for parametric roll using non-intrusive polynomial chaos. In: Proceedings of the 12th international ship stability workshop, Washington, DC, USA, 2011). In the present work, a polynomial chaos method is applied to a nonlinear computational ship dynamics model with normally distributed input parameters. Test cases were selected where parametric roll was expected to potentially occur. The resulting probability distributions are compared to the results of a Monte Carlo analysis. In general, these results demonstrate good agreement between Monte Carlo simulation and polynomial chaos in the absence of capsize with significant computation gains found with polynomial chaos. Overall, we conclude that polynomial chaos is an effective tool for reducing simulation time costs when studying parametric roll, and potentially other ship dynamics phenomena, particularly in the absence of capsize-like bifurcations.     

Parametric rolling prediction in irregular seas using combination of deterministic ship dynamics and probabilistic wave theory

In recent years there have been reports of serious accidents of parametric rolling for modern container ships and car carriers. For avoiding such accidents, a prediction method of parametric rolling in irregular seas is required. Since parametric rolling is practically non-ergodic, repetitions of numerical simulations or experiments could be not feasible to ascertain the behaviour. Therefore, in this paper, a method combining a stochastic approach with a deterministic approach in order to estimate the probabilistic index without such simple repetitions is developed. The ship's response in regular seas is estimated by solving an averaged system of the original 1-DoF roll model, and random waves necessary for occurrence of parametric rolling is achieved by using Longuet-Higgins’s or Kimura’s wave group theory. As a result, a fast and robust computation method of the probabilistic index is established. Finally, it is concluded that the proposed method is considered to be one of the useful tools for discussing the new IMO Intact Stability Code.     

基于减摇鳍辅助回转的船舶操纵性能研究

基于MMG分离式建模思想,考虑作用在船体、螺旋桨、舵、鳍的水动力作用,建立双桨双舵船舶四自由度非线性数学运动模型,对某船模在静水中的回转性能进行仿真分析,将单独舵控制的仿真结果与船模试验结果进行了验证和分析,并对比了单独舵控制和舵、鳍联合控制下的回转性能,结果表明鳍参与控制回转时能明显缓解回转过程中的横倾。     

Prediction of the maneuverability of a large container ship with twin propellers and twin rudders

The maneuvering characteristics of a large container ship with twin propellers and twin rudders were investigated using the horizontal planar motion mechanism (HPMM) test and computer simulation. A mathematical model for maneuvering motion with four degrees of freedom (DOF) for twin-propeller and twin-rudder systems was developed and included the effects of roll motion. To obtain the roll-coupling hydrodynamic coefficients of a container ship, a four-DOF HPMM system having a roll motion mechanism and a roll moment measurement system was used. At the full load condition, HPMM tests were carried out for two different 12 000-TEU container ship models, one with twin propellers and the other with a single propeller. Using the hydrodynamic coefficients obtained from the tests, computer simulations were carried out. Simulation results for the container ship with twin propellers and twin rudders were compared with the results for the container ship with a single propeller and single rudder.     

非线性非最小相位船舶舵减摇系统的滑模控制

  目的  针对存在系统未知非线性函数和外界随机扰动的欠驱动水面船舶舵减摇控制问题,提出一种基于多层循环神经网络的自适应非奇异快速终端滑模舵减摇控制器。  方法  首先,针对传统滑模控制中存在的奇异性和收敛性问题,引入非奇异快速终端滑模面,并在假设船舶模型已知的情况下设计滑模控制律;接着,对传统径向基神经网络进行改进,并利用改进后的神经网络去逼近系统未知非线性函数,以解决船舶航行时模型难以确立的问题,提高控制精度;然后,应用Lyapunov理论证明闭环系统的稳定性和有限时间收敛性,并推导出神经网络参数的自适应律;最后,对一艘多用途海军舰艇进行数值仿真分析。  结果  结果显示,当船舶处于航向保持工况时,所提出的控制器减摇率为50.41%,与非奇异快速终端滑模控制器相比提升了19.2%;当船舶处于变航向工况时,所提出的控制器减摇率为23.46%,与非奇异快速终端滑模控制器相比提升了12.59%。  结论  该方法可以为欠驱动船舶舵减摇控制设计提供参考。     

舵减摇系统的滑动控制

研究舰船在波浪中的横摇运动特性,探讨舵减摇系统控制机理。在考虑舵作为减摇设备使用的特性基础上,进行滑动控制规律设计,所得算法简单、实用性强     

Broaching prediction of a wave-piercing tumblehome vessel with twin screws and twin rudders

The new intact stability criteria which are under development at the International Maritime Organization (IMO) are required to cover a broaching phenomenon, well known as a great threat to high-speed vessels which can lead to capsizing. Some reports exist which demonstrate that their numerical models can predict a highly nonlinear phenomenon of broaching. However, additional validation studies are needed for unconventional vessels, in addition to conventional ones, to develop direct stability assessment methods for the new intact stability criteria. In this research, we selected as the subject ship a wave-piercing tumblehome vessel with twin screws and twin rudders, a design expected to be one of a new generation of high-speed monohull ships. Firstly, a series of captive model tests were conducted to measure the resistance, the manoeuvring forces, the wave-exciting forces, the heel-induced hydrodynamic forces, and the roll restoring variation for the unconventional tumblehome vessel. Secondly, the existing mathematical model which had been developed for broaching prediction of conventional vessels with a single propeller and a single rudder was extended to unconventional vessels with twin propellers and twin rudders. Finally, comparisons between numerical simulations and the existing free running model experiments were conducted. As a result, it was demonstrated that fair quantitative prediction of broaching is realised when the rudder force variation, the roll restoring variation and the heel-induced hydrodynamic force for large heel angles are taken into account.     

Prediction of ship steering capabilities with a fully nonlinear ship motion model. Part 1: Maneuvering in calm water

This paper introduces a new method for the prediction of ship maneuvering capabilities. The new method is added to a nonlinear six-degrees-of-freedom ship motion model named the digital, self-consistent ship experimental laboratory (DiSSEL). Based on the first principles of physics, when the ship is steered, the additional surge and sway forces and the yaw moment from the deflected rudder are computed. The rudder forces and moments are computed using rudder parameters such as the rudder area and the local flow velocity at the rudder, which includes contributions from the ship velocity and the propeller slipstream. The rudder forces and moments are added to the forces and moments on the hull, which are used to predict the motion of the ship in DiSSEL. The resulting motions of the ship influence the inflow into the rudder and thereby influence the force and moment on the rudder at each time step. The roll moment and resulting heel angle on the ship as it maneuvers are also predicted. Calm water turning circle predictions are presented and correlated with model test data for NSWCCD model 5514, a pre-contract DDG-51 hull form. Good correlations are shown for both the turning circle track and the heel angle of the model during the turn. The prediction for a ship maneuvering in incident waves will be presented in Part 2. DiSSEL can be applied for any arbitrary hull geometry. No empirical parameterization is used, except for the influence of the propeller slipstream on the rudder, which is included using a flow acceleration factor.     

基于多目标遗传算法舵鳍联合减摇系统能量优化研究（英文）

Energy optimization is one of the key problems for ship roll reduction systems in the last decade. According to the nonlinear characteristics of ship motion, the four degrees of freedom nonlinear model of Fin/Rudder roll stabilization can be established. This paper analyzes energy consumption caused by overcoming the resistance and the yaw, which is added to the fin/rudder roll stabilization system as new performance index. In order to achieve the purpose of the roll reduction, ship course keeping and energy optimization, the self-tuning PID controller based on the multi-objective genetic algorithm(MOGA) method is used to optimize performance index. In addition, random weight coefficient is adopted to build a multi-objective genetic algorithm optimization model. The objective function is improved so that the objective function can be normalized to a constant level. Simulation results showed that the control method based on MOGA, compared with the traditional control method, not only improves the efficiency of roll stabilization and yaw control precision, but also optimizes the energy of the system. The proposed methodology can get a better performance at different sea states.