改进遗传算法的船舶航行路径规划方法

船舶航行环境十分复杂,路径规划是保证船舶智能航行的基本技术,针对当前船舶航行路径规划方法存在搜索最优路径速度慢、得到最优路径质量差等缺陷,设计了基于改进遗传算法的船舶航行路径规划方法。首先对船舶航行路径规划原理进行分析,构建船舶航行路径规划的建模环境,然后产生船舶航行路径规划的可行解,引入改进遗传算法模拟生物进化机制对船舶航行路径规划可行解进行分析,搜索到最优的船舶航行路径规划方案,最后在Matlab 2017平台上进行了船舶航行路径规划仿真测试。改进遗传算法不仅能够在有效时间内找到最优的船舶航行路径规划方案,让船舶航行路径十分安全,能够有效避开所有障碍物,而且找到船舶航行路径规划方案的迭代次数明显减少,是有一种有效的船舶航行路径规划方法。     

Path planning method for unmanned surface vehicle with controllable distance from obstacles北大核心CSCD

[目的]为了解决水面无人艇(USV)路径规划中安全性和平滑性方面的问题,提出一种与障碍物距离可控的USV路径规划方法。[方法]首先,结合雷达图像生成栅格化环境信息,利用维诺场算法(VFA)为每个栅格添加危险势场并建立航行界限;其次,建立与航行界限关联的危险度函数对A^(*)算法的评价函数进行改进,利用改进的A^(*)算法进行路径规划;最后,针对航行路径转向角较大的问题,采用梯度下降法(GDM)进行航行路径的平滑处理,得到满足USV实际航行要求的连续平滑路径。[结果]仿真结果表明,所提路径规划方法通过设置不同的航行界限可以实现路径与障碍物之间距离的控制且平滑性符合航行要求。[结论]该方法在USV路径规划过程中具有一定的合理性和有效性,可为USV自主避障决策提供参考。     

自主式水下机器人最优路径规划问题的研究

路径规划是水下机器人实现自主航行的重要环节。根据自主式水下机器人的动力学性质，路径规划的特点以及实现智能行为的要求，采用基于案例的遗传算法，实现了自主式水下机器人最优路径规划。给出该方案的基本框架和算法，在基于案例类比的学习方法中引入模糊多属性综合决策的方法建立决策算子进行案例的匹配，在遗传算法中实际知识的指导，适当地改进遗传算子，加快搜索速度。仿真结果证明该路径规划方法能够取得较好的规划结果，使自主式水下机器人具有了一定的自主导航，自主避障和自主作业的能力。     

船舶智能决策关键技术实现方案研究

为研究船舶智能航行关键技术智能决策实现过程方案,对智能决策的实现过程进行分析,并对智能决策过程中的关键问题确定航线智能规划目标、建立航线规划模型、确定避碰决策目标、碰撞危险度等进行了分析,提出智能决策实现过程方案。     

人工智能算法的舰船路径规划

为了实现对舰船航行的智能调度,需要进行舰船路径规划设计,提出一种基于人工粒子群智能算法的舰船路径规划方法。构建舰船航行路径分布的网格结构模型,将舰船航行区域内的各个对象表达为人工粒子群个体,采用四元素的扩展卡尔曼滤波方法构造舰船航行路径规划的约束参量模型。构造舰船航行路径规划的控制目标函数,以舰船动态性能和稳态性能为优化目标,采用人工智能群算法进行航行路径的自适应寻优,实现舰船路径规划。结果表明,采用该方法进行舰船路径规划,能准确跟踪舰船航行的方位角和姿态角,实现路径实时跟踪,提高了舰船路径的准确规划能力。     

基于改进人工势场的避障路径规划策略研究

随着战争形势的无人化、多样化和跨域化发展,水下无人航行器作为各军事强国抢占水下作战域和海洋不对称作战优势的主要抓手,在未来战争中发挥着越来越重要的作用。由于海洋非结构化环境的复杂性,水下无人航行器在执行任务过程中,需能够在无人干预情况下进行系列操作和任务决策。本文针对水下无人航行器局部路径规划,提出基于速度矢量判断的改进人工势场法的避障航路规划策略,通过增加障碍物斥力场范围,强化目标点附近的引力场,优化障碍物斥力系数,并通过速度矢量判断旋转方向,使得水下无人航行器能够结合环境感知信息进行路径实时调整,最终能够达到安全快速避障。最后结合航行器流体动力与运动控制一体化仿真模型进行仿真分析,验证提出算法的有效性。     

船舶航线规划中的精确控制算法研究

海洋开发及海上贸易不断深入,船舶作为海上最重要的交通工具朝着大型化、强动力及智能化方向发展。随之带来的是船舶航行速率的提高及船只密度的增加,船舶的安全航行越来越成为海洋开发关注的重点。船舶航行规划路径的精度控制直接关系到船舶的安全驾驶,操控过程中航迹误差控制是航行路径规划最重要的性能指标。本文研究船舶航行的操纵运行模型,提出一种基于遗传算法的航线精确控制非线性模型,最后对其进行仿真。     

基于改进蚁群算法的船舶冰区航行路径规划

在北极航道开通的背景下,针对在冰区航行环境中船舶航行路径选择的特殊性,通过改进蚁群算法提高船舶航行路径的规划效果。综合考虑航线距离、航行操作复杂度和流冰规避在内的冰区航行路径影响因素,建立路径选择多目标规划模型,结合人工势场法对蚁群算法进行改进,通过人工势场法获得初始路径和节点间距离因素构造启发信息,并以电子海图为基础建立海冰覆盖率分别为30%和50%情况下的冰区航道环境栅格模型,将算法应用在栅格模型中对算法进行验证。结果表明:该算法实现简单,规划的路径优良,能够有效地满足船舶在冰区复杂环境中航行路径规划的需要。     

基于混合蚁群算法的无人船航行路径自主规划

路径规划是无人船自主导航的核心问题。由于无人船当前位置以及目标位置的确定受到障碍物影响,最佳航行路径的获取难度较大。为此,提出基于混合蚁群算法的无人船航行路径自主规划方法。采用栅格法构建无人船工作环境模型,由上至下、由左至右的对栅格完成编号处理,划分安全区域与障碍物区域。构建无人船航行路径自主规划数学模型,设定地形与威胁、航程上限以及路径平滑度等约束条件。针对蚁群算法初始搜索效率差等问题,将其与粒子群算法相结合,提出混合蚁群算法。利用该算法求解无人船航行路径自主规划数学模型。实验结果显示,研究方法具有较高的路径规划准确性,路径长度、平均能耗及路径规划时间指标均较优。     

复杂海面环境下船舶航行最优路径规划数学模型

以保障船舶安全航行为基础,以提升船舶续航能力为目的,研究复杂海面环境下船舶航行最优路径规划数学模型。利用概率路图法将船舶航行的、具有复杂海面环境特征的全局海域环境转换成离散空间,采用连接采样点获取离散空间若干条由初始点至目的点的路径,生成路线图。依照某船舶航行性能评价指标,构建航行路线图中的最优路径规划数学模型,考虑复杂海面环境设定地形与威胁约束、船舶转弯角度约束以及路径平滑度约束等。采用基于震荡型入侵野草优化算法求解数学模型,在所构建的路线图内获取一个符合标准的解向量,即最优路径规划结果。实验结果显示,该模型能够有效获取最优路径规划结果,以能耗最低为船舶航行性能评价指标时更利于船舶续航。     

Long-term correlation structure of wave loads using simulation

This paper proposes a new method for combining the lifetime wave-induced sectional forces and moments that are acting on the ship structure. The method is based on load simulation and can be used to determine the exceedance probabilities of any linear and nonlinear long-term load combination. It can also be used to determine the long-term correlation structure between these loads in the form of the long-term correlation coefficients. They are essential part of the load combination procedures in design and strength evaluations as well as in the fatigue and reliability analysis of ship structures.The simulation method treats the non-stationary wave elevations during the ship’s entire life (long-term) as a sequence of different stationary Gaussian stochastic processes. It uses the rejection sampling technique for the sea state generation, depending on the ship’s current position and the season. Ship’s operational profile is then determined conditional on the current sea state and the ship’s position along its route. The sampling technique significantly reduces the number of sea state-operational profile combinations required for achieving the convergence of the long-term statistical properties of the loads. This technique can even be used in combination with the existing long-term methods in order to reduce the number of required weightings of the short-term CDFs. The simulation method does, however, rely on the assumption that the ship is a linear system, but no assumptions are needed regarding the short-term CDF of the load peaks.The load time series are simulated from the load spectra in each sea state, taking into account the effects of loading condition, heading, speed, seasonality, voluntary as well as involuntary speed reduction in severe sea states and the short-crested nature of the ocean waves. During the simulation procedure, special care has been given to maintaining the correct phase relation between all the loads. Therefore, time series of various load combinations, including the nonlinear ones, can be obtained and their correlation structure examined. The simulation time can be significantly reduced (to the order of minutes rather than hours and days) by introducing the seasonal variations of the ocean waves into a single voyage simulation. The estimate of the long-term correlation coefficient, obtained by simulating only a single voyage with the correct representation of seasonality, approaches the true correlation coefficient in probability. This method can be applied to any ship and any route, or multiple routes as long as the percentage of the ship’s total lifetime spent in each of them is known.A study has been conducted to investigate the effects of ship type, route and the longitudinal position of the loads on the values of the correlation coefficients between six different sectional loads; vertical, horizontal and twisting moments, as well as shear, horizontal and axial forces. Three ocean-going ship types have been considered; bulk carrier, containership and tanker, all navigating on one of the three busy ship routes; North America-Europe, Asia-North America and Asia-Europe. Finally, the correlation coefficient estimates have been calculated for five different positions along the ship’s length to investigate the longitudinal variation of the correlation coefficient.     

Economies of container ship size: a new evaluation

Based on recent operation performance data, the earnings and costs of container service have been investigated in the context of two inches developed by the japanese and used elsewhere in East Asian shipping: charater base. Although the average size of container ships on the world's main trade routes has increased over the past two decades it is dangerous to generalize about the ecnomies of scale derived from larger ship size. The effects of ship's on voyage results vary in accordance with such factors as ship's purchase price, level of running costs, level of freight rates, voyage length, achieved load factors and accounting methods used for allocating fixed costs. The question of optimum vessel, therfore, has no generally applicable answer. Shipowners must compromise.     

Economies of container ship size: a new evaluation

Based on recent operation performance data, the earnings and costs of container service have been investigated in the context of two inches developed by the japanese and used elsewhere in East Asian shipping: charater base. Although the average size of container ships on the world's main trade routes has increased over the past two decades it is dangerous to generalize about the ecnomies of scale derived from larger ship size. The effects of ship's on voyage results vary in accordance with such factors as ship's purchase price, level of running costs, level of freight rates, voyage length, achieved load factors and accounting methods used for allocating fixed costs. The question of optimum vessel, therfore, has no generally applicable answer. Shipowners must compromise.     

船舶变频空调风机节能技术研究

应用当量温差计算法对欧—亚航线上船舶在不同航区的空调动态负荷和风机可调送风量进行了定量描述;阐述了变频技术应用于空调风机的途径;得出了空调风机变频调速,舒适性好,节能率高达５８％以上,具有广阔发展前景的结论     

船舶气象导航最省燃料航线研究

船舶气象导航是保证船舶航行安全和节能的重要手段。本文应用最佳控制理论研究和建立船舶最省燃料航线数学模型。在分析比较船舶最短时间航线和最省燃料航线数学模型的基础上，讨论了最省燃料航线算法实现。并针对冬季北太平洋进行了最省燃料航线模拟试验。     

The effects of slow steaming on the environmental performance in liner shipping

The environment issue is one of the significant challenges that the liner shipping industry has to face. The International Maritime Organization (IMO) has set a goal to reduce greenhouse gas (GHG) emissions from existing vessels by 20–50% by 2050 and develop the Energy Efficiency Operational Indicator (EEOI) as a measure for energy efficiency. To achieve this goal, IMO has suggested three basic approaches: the enlargement of vessel size, the reduction of voyage speed, and the application of new technologies. In recent times, liners have adopted slow steaming and decelerated the voyage speed to 15–18 knots on major routes. This is because slow steaming is helpful in reducing operating costs and GHG emissions. However, it also creates negative effects that influence the operating costs and the amount of GHG emissions at the same time.

This study started with the basic question: Is it true that as voyage speed reduces, the operating costs and CO₂ emissions can be reduced at the same time? If this is true, liners will definitely decelerate their voyage speed themselves as much as possible so that they can increase their profits and improve the level of environmental performance. However, if this is not true, then liners will concentrate just on increasing their profits by not considering environmental factors. This led the authors to set out three objectives: (1) to analyze the relationship between voyage speed and the amount of CO₂ emissions and to estimate the changes by slow steaming in liner shipping; (2) to analyze the relationship between voyage speed and the operating costs on a loop; and (3) to find the optimal voyage speed as a solution to maximize the reduction of CO₂ emissions at the lowest operating cost, thus satisfying the reduction target of IMO.     

谈航行数据记录仪的港口国监督检查

文中在分析航行数据记录仪主要组成及功能的基础上,以IMO海上安全委员会通过的航行数据记录仪的相关决议为检查依据,结合港口国监督检查实践经验总结出航行数据记录仪检查要点及方法,结合检查实例进行阐述,以期能给同行提供一些有益的参考。     

基于能效管理的船舶航速系统优化设计

在目前航运业市场低迷、运力过剩的境况下,航运企业愈发重视对燃油成本的控制,对航速节油也有了更多的要求.为此,提出基于能效管理的船舶航速系统优化设计,计算船舶营运的经济航速.并结合航次的航线、航向、航速及每段航线的天气、水文等信息,对船舶营运航速的模型进行不断优化调整,指导船舶航行,为船舶及船岸操作提供决策支持,以达到优化节能的目的.     

穿越南沙群岛的航线设计

南沙群岛是我国南海诸岛中分布最广、范围最大、岛礁最多的一个岛屿,但长期以来,很少有船舶驶入。由于货物运输原因,我轮频繁来往于香港和东马,经认真研究分析资料,设计了四条可以穿越南沙群岛的航线,经过10多个航次的航行检验,该航线能够保证船舶安全。此文对此穿越航线作了介绍。     

考虑不确定性因素的路径优化(英文)

A route optimization methodology in the frame of an onboard decision support/guidance system for the ship’s master has been developed and is presented in this paper.The method aims at the minimization of the fuel voyage cost and the risks related to the ship’s seakeeping performance expected to be within acceptable limits of voyage duration.Parts of this methodology were implemented by interfacing alternative probability assessment methods,such as Monte Carlo,first order reliability method(FORM) and second order reliability method(SORM),and a 3-D seakeeping code,including a software tool for the calculation of the added resistance in waves of NTUA-SDL.The entire system was integrated within the probabilistic analysis software PROBAN.Two of the main modules for the calculation of added resistance and the probabilistic assessment for the considered seakeeping hazards with respect to exceedance levels of predefined threshold values are herein elaborated and validation studies proved their efficiency in view of their implementation into an on-board optimization system.