基于支持向量回归机的船舶操纵运动在线辨识建模

采用滚动时间窗的方法实现支持向量机的在线辨识。以船舶操纵运动响应模型为研究对象,并由10°/10°和15°/15°仿真Z形试验数据构造支持向量机参数辨识所需的训练样本对,应用支持向量机进行船舶操纵运动在线辨识建模,回归操纵运动响应模型中的操纵性指数,并利用建立的响应模型进行Z形试验的数值模拟。将Z形试验数值模拟结果同仿真Z形试验数据进行比较,结果表明,在线式支持向量回归机是一种进行船舶操纵运动在线辨识建模的有效方法。     

基于支持向量回归机的船舶操纵运动在线辨识建模

采用滚动时间窗的方法实现支持向量机的在线辨识。以船舶操纵运动响应模型为研究对象,并由10°/10°和15°/15°仿真Z形试验数据构造支持向量机参数辨识所需的训练样本对,应用支持向量机进行船舶操纵运动在线辨识建模,回归操纵运动响应模型中的操纵性指数,并利用建立的响应模型进行Z形试验的数值模拟。将Z形试验数值模拟结果同仿真Z形试验数据进行比较,结果表明,在线式支持向量回归机是一种进行船舶操纵运动在线辨识建模的有效方法。     

基于改进LSSVM的船舶操纵运动模型在线参数辨识方法

为实现船舶操纵性的在线预报及自适应运动控制,针对Nomoto二阶非线性运动模型参数辨识问题,将最小二乘支持向量机(least squares support vector machines,LSSVM)与多新息方法相结合,提出一种新的多新息在线LSSVM辨识建模方法。试验结果表明,使用所提出的算法辨识的模型进行预报的拟合误差可达到4.76%以下,能准确拟合船舶操纵运动模型。     

基于支持向量机的水下航行器操纵运动在线建模

本文对水下航行器的操纵运动在线建模进行研究。使用增量式最小二乘法辨识得到了MARIUS AUV的水动力导数。为了提高辨识精度,使用积分型辨识样本结构进行输入输出样本对的构造。基于约束模试验获取的水动力导数,进行操纵运动仿真,得到纵向速度、横向速度、摇首角速度和舵角等样本参数。通过试验水动力导数和辨识得到的水动力导数对比,表明辨识算法的有效性。该研究对水下航行器操纵运动的在线建模和控制应用具有重要意义。     

基于支持向量机的水下航行器操纵运动在线建模

本文对水下航行器的操纵运动在线建模进行研究。使用增量式最小二乘法辨识得到了 MARIUS AUV的水动力导数。为了提高辨识精度,使用积分型辨识样本结构进行输入输出样本对的构造。基于约束模试验获取的水动力导数,进行操纵运动仿真,得到纵向速度、横向速度、摇首角速度和舵角等样本参数。通过试验水动力导数和辨识得到的水动力导数对比,表明辨识算法的有效性。该研究对水下航行器操纵运动的在线建模和控制应用具有重要意义。     

基于LS-SVM的船舶操纵运动在线建模

基于最小二乘支持向量机(LS-SVM)和积分型辨识样本结构开展了船舶操纵运动的在线建模.以整体型Abkow-itz模型为辨识对象,大阪号油轮作为具体研究对象.在操纵运动仿真时,采用40个粘性类水动力导数的Abkowitz模型,但是在参数辨识时,采用了仅具有20个粘性类水动力导数的简化模型.为了对建模方法的有效性进行检验,将辨识得到的水动力导数与其原始值进行了比较,同时也针对辨识模型和原始模型的操纵运动仿真进行了比较.辨识结果表明,使用简化模型进行船舶操纵运动的在线建模是合适的,具有较好的预报效果和较高的精度.     

基于支持向量机的水下机器人操纵运动参数辨识

根据平面运动机构试验所得到的水动力系数确定水下运载器的运动方程,应用最小二乘支持向量机对水下运载器的试验数据进行分析,辨识得到了水动力系数,并将辨识得到的参数同平面运动机构试验所确定的参数相比,验证了最小二乘支持向量机进行水下运载器操纵运动参数辨识的有效性。根据所辨识的水动力系数进行了模型验证,证明所辨识得到的水动力参数是可靠的。该方法对水下运载器的操纵和控制的研究有重要意义。     

基于岭回归方法的船舶操纵运动建模

基于自航模试验的系统辨识方法是一种有效的船舶操纵运动建模方法.通过对舵角和转艏角速度试验数据的分析,用岭回归方法确定了船舶操纵运动数学模型中的模型参数,进行了操纵运动预报仿真并同自航模试验数据对比,数值仿真结果验证了方法的有效性.     

基于支持向量回归机和粒子群算法的船舶操纵运动模型辨识

基于仿真的Z形试验数据,应用支持向量回归机对船舶操纵运动响应模型进行了机理建模,从核函数结构中得到了模型中的操纵性指数,并利用建立的响应模型进行了Z形试验的运动预报,同时引入粒子群算法对惩罚因子C值进行寻优,以减少惩罚因子C值选择的任意性对船舶操纵运动模型辨识精度产生的不利影响。通过将运动预报结果同仿真试验数据进行比较,验证了文中方法的有效性。     

基于ν-支持向量机的波浪中船舶操纵运动辨识建模

本文采用系统辨识方法对船舶在波浪中的三自由度操纵运动进行黑箱建模。以KCS船为研究对象，建模所需的数据由规则波中的船模回转试验获得。分别利用原始数据及经低通滤波处理后的数据，应用ν-支持向量机进行黑箱建模。进一步地，利用所建立的模型进行运动预报，并将预报结果与真实的试验值进行比较，对所提出的建模方法进行验证。结果表明，ν-支持向量机是一种可进行波浪中的船舶操纵运动辨识建模的有效方法。     

Modeling of ship maneuvering motion using neural networks

In this paper, Neural Networks (NNs) are used in the modeling of ship maneuvering motion. A nonlinear response model and a linear hydrodynamic model of ship maneuvering motion are also investigated. The maneuverability indices and linear non-dimensional hydrodynamic derivatives in the models are identified by using two-layer feed forward NNs. The stability of parametric estimation is confirmed. Then, the ship maneuvering motion is predicted based on the obtained models. A comparison between the predicted results and the model test results demonstrates the validity of the proposed modeling method.     

基于神经网络的船舶操纵运动建模研究（英文）

In this paper, Neural Networks(NNs) are used in the modeling of ship maneuvering motion. A nonlinear response model and a linear hydrodynamic model of ship maneuvering motion are also investigated. The maneuverability indices and linear non-dimensional hydrodynamic derivatives in the models are identified by using two-layer feed forward NNs. The stability of parametric estimation is confirmed. Then, the ship maneuvering motion is predicted based on the obtained models. A comparison between the predicted results and the model test results demonstrates the validity of the proposed modeling method.     

船舶操纵水动力导数的数值求解及敏感度分析

[目的]为了兼顾船舶操纵运动预报的成本与精度,基于数值计算方法,结合水动力导数敏感度分析,提出一种船舶操纵运动预报方法.[方法]首先,求解RANS方程,应用流体体积(VOF)法捕捉自由液面,采用动态网格方法对DTMB 5415船型进行约束运动的数值计算,并将回归得到的线性水动力导数与试验值进行对比,验证数值方案的有效性...     

操纵运动船舶的水动力计算研究

以船舶操纵水动力预报为研究背景,通过对商用计算流体力学软件FLUENT的二次开发,采用其动网格技术以及后处理系统,对大型船舶操纵水动力导数进行了数值计算.船体按照斜航、不同舵角、纯横荡和纯首摇等状态做运动,得出随船坐标系下作用于其上的水动力及力矩.通过进行基于最小二乘法的曲线拟合,最终求得船舶操纵水动力导数.计算结果与势流理论计算结果一致,表明了所提出的计算方法适用于复杂船舶运动的水动力导数计算.     

Finite-volume simulation of flows about a ship in maneuvering motion

A finite-volume method of computing the viscous flow field about a ship in maneuvering motion was developed. The time-dependent Navier-Stokes equation discretized in the generalized boundary-fitted curvilinear coordinate system is solved numerically. A third-order upwind differencing scheme, a marker and cell (MAC)-type explicit time marching solution algorithm and a simplified subgrid scale (SGS) turbulence model are adopted. The simulation method is formulated, including the movement of a computational grid fitted to the body boundary that allows computation of the flow field around a body under unsteady motion. To estimate the maneuvering ability of a ship, the accurate prediction of the hydrodynamic forces and moments of the hull is important. Therefore, experimental methods of finding the hydrodynamic forces of a ship in maneuvering motion, such as the oblique towing test, the circular motion test (CMT) and planar motion mechanism (PMM) test, were established. Numerical simulation methods for those captive model experiments were developed introducing computational fluid dynamics (CFD). First, numerical methods for steady oblique tow and steady turn simulation were developed and then extended to unsteady forced motion. Simulations were conducted about several realistic hulls, and the results were verified by comparisons with measured results obtained in model experiments. Hydrodynamic forces and the moment, the longitudinal distribution of the hydrodynamic lateral force, and the pressure distribution on the hull surface showed good agreement.     

Course stability and yaw motion of a ship in steady wind

In order to achieve safe navigation, it is important to be able to understand and calculate the effects of an external force on the maneuvering behavior of a ship. This paper analyzes the course stability and yaw motion of a ship traveling under steady wind conditions. A course stability criterion and approximate formulae for the yaw motion in steady wind, including the aero/hydrodynamic force derivatives for the ship, are derived. To confirm the reliability of the criterion and formulae, they were used to investigate a pure car carrier in steady wind. The results of this investigation revealed that course instability appears in the head and following wind directions, mainly under the influence of aerodynamic derivatives with respect to the yaw restoring forces. However, this course instability can be reduced by applying steering control. For winds ranging from head winds to beam winds, yaw oscillation appears when the period is relatively long and the damping is small. The analytical formulae derived here can be used to gain a better understanding of ship maneuvering behavior in steady wind.