Aheuristic Algorithm for Berth Scheduling Problem in Container Ports

In this paper,the berth scheduling problem is transformed into a special two-dimensional packing problem with some constraints.A nonlinear programming model for the problem is established,and a heuristic algorithm is proposed to solve the model.Simulation results show that the algorithm can improve the utilization of berths on discrete berth scheduling in the container port.

Study on Ship Automatic Berthing System with Mooring Lines

This study describes an automatic berthing system with mooring lines. It is designed to be berthed by using mooring device on the upper deck of a ship. It is to berth once maintaining parallel with the quay by controlling both forward and aft breast lines. Berthing method is used through length adjustment of mooring lines connected between ship and quay by controlling the angular velocity and the torque of hydraulic motor in mooring device. The study is conducted under three changing conditions of draft, such as even-keel, rise of the gravity center and trim to stern. Variables affecting berthing stability are determined based on the control performance of each condition. Bond graphs method is used to model the system. Controller is designed as PID control method of reference-model algorithm. The control program is composed of synchronous control system based on the equations derived with the numerical analysis. The tank test is conducted to verify the usefulness of the control program.

Integration of Berth Allocation and Quay Crane Assignment in Tidal Container Ports

Tide is a significant factor which interferes with the berthing and departing operations of vessels in tidal ports. It is a preferable way to incorporate this factor into the simultaneous berth allocation and quay crane( QC) assignment problem( BACAP) in order to facilitate the realistic decision-making process at container terminal. For this purpose,an integrated optimization model is built with tidal time windows as forbidden intervals for berthing or departing. A hind-and-fore adjustment heuristic is proposed and applied under an iterative optimization framework. Numerical experiment shows the satisfying performance of the proposed algorithm.

Real Time Math Simulation of Contact Interaction during Spacecraft Docking and Berthing

Contact reactions of guide surfaces of assembly interfaces lead to the decreasing of theirs lateral and angular misalignments. The focus of this paper is the development of algorithms for computation of guide surfaces contact forces with acceptable engineering accuracy for real time simulation of assembly operations. Therefore, each complex guide surface is described as a set of contacting elements. Each contacting element for one＇s part can be represented by a finite set of geometric primitives which geometry is described by low order algebraic equations. So contact conditions and geometric parameters for all pairs of primitives are determined by analytical expressions. Math models are developed for two classes of contact interaction. The first class includes all cases when each contacting surface has several degrees of freedom of motion. Therefore, contact reactions introduced into differential equations of motion are calculated by using contacting elements penetrations, stiffness and damping parameters. The second class corresponds to all cases when one of contacting surfaces has insignificant inertia and only one degree of freedom of relative displacement counteracted by a spring. Here contact reactions are calculated from spring tension with any practical accuracy. This is very useful in some practical applications. Presented algorithms provide real time simulation together with some approaches for reduction of redundant comnutations.

Modeling and Simulation of Automatic Berthing based on Bow and Stern Thruster Assist for Unmanned Surface Vehicle

In order to solve the technical problems of autonomous berthing of the Unmanned Surface Vehicle(USV),this research has met the requirements of maneuverability berthing under different conditions by effectively using the bow and stern thrusters,which is a technological breakthrough in actual production and life.Based on the MMG model,the maneuverability mathematical model of the USV with bow and stern thruster was established.And the motion simulation of USV maneuvering was carried out through the numerical simulation calculation.Then the berthing plan was designed based on the maneuverability analysis of the USV low-speed motion,and the simulation of automatic berthing for USV was carried out.The research results of this paper can be of certain practical significance for the USV based on the support of the bow and stern thruster in the berthing.At the same time,it also provides a certain theoretical reference for the handling of the USV automatic berthing.

Experimental Study on Allowable Berthing and Mooring Conditions of An Oil Tanker

When an oil tanker under the combined action of wind, waves and tidal current and is berthed or moored to a platform, the impact forces on the fenders and the tensile force in the mooring lines are important factors in the studies of berthing and mooring conditions. Based on the experiment of a berthing and mooring tanker model under the action of wind, wave and tidal current in the same direction, this paper studies the allowable berthing and mooring conditions by considering the tensile forces of mooring lines and impact forces on the fenders, as well as the impact energy on the fenders. And a method has been proposed here for motion amplitude analysis. A successful method to decrease impact forces on the fenders is put forward. Blowing in wind and blowing off wind and different angles between waves and the fenders are considered in the experimental study. In the berthing tests of the tanker model, the impact forces are measured and the impact energy is calculated, then the berthing conditions are determined. In the mooring tests of the tanker model, the mooring line tensile forces and impact forces are measured, and the allowable mooring conditions are given that will be useful to engineering design.

An Improved Genetic Algorithm for Berth Scheduling at Bulk Terminal

Berth and loading and unloading machinery are not only the mainfactors that affecting the terminal operation, but also the main starting point ofenergy saving and emission reduction. In this paper, a genetic Algorithm Framework is designed for the berth allocation with low carbon and high efficiency atbulk terminal. In solving the problem, the scheduler’s experience is transformedinto a regular way to obtain the initial solution. The individual is represented as achromosome, and the sub-chromosomes are encoded as integers, the roulettewheel method is used for selection, the two-point crossing method is used forcross, and the exchange variation method is used for variation in the procedureof designing the Algorithm. Considering the complexity of berth schedulingproblem and the diversity of constraints and boundary conditions, the geneticalgorithm combines with system simulation to get the final scheme of berthallocation. This model and algorithm are verified to be practical by analyzingmultiple sets of examples of shorelines with different lengths. When comparedwith the traditional algorithms in three aspects which includes berth offsetdistance, departure delay cost and energy consumption of portal crane, the resultindicates that the improved algorithm is more effective and feasible. The studywill help to lower energy consumption and resource waste, reduce environmentalpollution, and provide a reference for low-carbon, green and sustainable development of the terminal.

Berth-crane allocation under uncertainty:dynamic modeling and nested Tabu search

The integrated berth-crane allocation problem at container terminals is addressed under the uncertainty of vessel arrival time at operational level. To ensure both robustness and flexibility of the 2-stage decision processes,a dynamic decision framework is proposed based on the dynamic analysis of information and operation at container terminal. A mixed integer programming model is established aiming at minimizing total cost of all vessels,including the cost of fixed to-be-executed decisions in the 1^(st) stage and expected cost of the adjustable stochastic-scenario-based decisions of all scenarios in the 2^(nd) stage. A multi-layer nested Tabu search is proposed for each epoch dynamically. Finally numerical experiments have been conducted to testify the effectiveness and efficiency of the proposed model and algorithm.

Numerical Prediction of Hydrodynamic Forces on A Berthed Ship Induced by A Passing Ship in Different Waterway Geometries

An investigation has been conducted to quantify the effect of waterway geometry on the form and magnitude of forces and moment experienced by a berthed ship due to a passing ship.By using the dynamic mesh technique and solving the unsteady RANS equations in conjunction with a RNG k？ε turbulence model,numerical simulation of the three-dimensional unsteady viscous flow around a passing ship and a berthed ship in different waterway geometries is conducted,and the hydrodynamic forces and moment acting on the berthed ship are calculated.The proposed method is verified by comparing the numerical results with existing empirical curves and a selection of results from model scale experiments.The calculated interaction forces and moment are presented for six different waterway geometries.The magnitude of the peak values and the form of the forces and moment on the berthed ship for different cases are investigated to assess the effect of the waterway geometry.The results of present study can provide certain guidance on safe maneuvering of a ship passing by a berthed ship.

Nesting and Berth Allocation by an Expert System Using Heuristic Search

Nesting is a common problem in industries such as shipbuilding, auto-maker, clothing, shoe-making, and furniture, in which various parts are cut off from a stock or stocks while minimizing the wastes or maximizing the utilization of the stock. Berth allocation at seaside is also considered one form of two dimensional nesting problems, in which a ship is assigned a location for service during a certain time slot. This paper presents an expert system using a heuristic search method for nesting problems. The parts and stocks are represented by pixels with which utility function is used to evaluate current state in search tree. The system is developed in CLIPS, an expert system shell and applied to various example problems with different constraints and to a berth allocation example to illustrate its applicability under different conditions.

Collaborative Optimization of Berth Allocation and Yard Storage in Container Terminals

Considering the interaction between the berth and the yard,this paper studies the collaborative optimization problem of berth allocation and yard storage from the point of the ships over a certain planning period.This collaborative optimization problem is formulated as the integer programming,which aims at minimizing the total truck travel distance.And decision variables are the berthing positions for visiting ships and the storage positions for export containers.Meanwhile,this paper demonstrates the complexity of the problem in theory.And the hybrid tabu genetic algorithm is designed to solve the problem to obtain the optimal berth allocation position and export container storage position.For this algorithm,the rule is applied to generate the initial feasible solutions,and the crossover and mutation operation are simultaneously applied to optimize the initial solutions.Finally,this paper discusses two different scenes:the same berth scene and the same ship scene.The influence of two different scenes on truck travel distance is analyzed by different numerical examples.Numerical examples’results show that the collaborative optimization of berth allocation and yard storage can effectively shorten the truck travel distance and improve the efficiency of terminal operation,which provides the decision support for terminal operators.

An Analysis of Net Berth Productivity in the Handling Operations with Dry Bulk Cargoes in a Seaport

Productivity at the berth is one from the group of port productivity measures which is closely tied to ship turnaround times.Net berth productivity is value of productivity related to the operational time at the berth.Based on the facts identified from available literature about minor share of researches related to the net berth productivity in the handling operations with dry bulk cargoes in a seaport,it was decided to take this port productivity metrics as an object of a research.After a detailed analysis of different categories of the net berth productivity in the handling operations with dry bulks,key groups of influential factors which determine values of the net berth productivity are identified and systematized.Some principal elements related to improving net berth productivity are taken into consideration,too.Concrete results shown in this paper are related to the Dry Bulk Cargo Terminal in the Port of Bar(Montenegro).

基于改进反步滑模控制算法的拖轮自主靠泊控制

[目的]针对拖轮的自主靠泊控制问题,研究基于虚拟船领导的目标跟踪控制策略在拖轮自主靠泊中的应用。[方法]首先,将拖轮的自主靠泊过程转变为虚拟拖轮和实际拖轮的目标跟踪控制过程;然后,设计靠泊系统的运动学模型,考虑靠泊场景中的特殊环境干扰,使用反步法和滑模控制法(SMC)设计全回转尾推进拖轮的自主靠泊控制器,提供了3种不同的滑模面设计并使用李雅普诺夫函数进行稳定性验证;最后,采用仿真实验的方式,通过靠泊轨迹、速度误差和距离误差来对控制的效果进行验证。[结果]仿真实验结果表明,设计的拖轮自主靠泊控制策略以及控制器在拖轮自主靠泊场景中具有较好的效果,面对系统的不确定干扰有较好的表现。[结论]该控制策略以及靠泊控制器的适用性以及鲁棒性较好,以全新的角度实现了拖轮自主靠泊控制,为后续拖轮的靠泊控制研究提供了新的方向。

考虑海铁联运的集装箱码头泊位分配优化

在海铁联运背景下,协同考虑到港船舶及铁路班列特点,优化集装箱码头泊位分配,对于提高港口作业效率至关重要。在满足码头岸线、泊位水深、岸桥等资源约束前提下,综合考虑船舶服务优先级和偏好泊位、铁路集装箱班列到发时间等约束,以船舶在港停留时间和泊位偏移惩罚时间最小为优化目标,建立海铁联运集装箱码头泊位分配优化模型;针对模型特点,设计自适应遗传算法进行求解,选取计划周期48 h内的到港船舶数据进行案例分析,通过MATLAB数值实验,得到符合船舶服务优先级和泊位偏好要求且契合铁路班列开行计划的海铁联运码头泊位分配方案。数值实验结果表明:在海铁联运协同优化条件下,船舶平均等泊时间为2.9 min,最大等泊时间为11.4 min,同时船舶的靠泊位置与偏好泊位之间的距离均不超过100 m,船舶在港的停留时间及偏好泊位差都得到了较好的控制。研究可进一步优化海铁联运集装箱码头泊位分配方案,有利于提高海铁联运集装箱在港转运效率。

欠驱商船的自主靠泊轨迹规划研究

针对大型商船在自主靠泊时的轨迹规划任务,分别考虑远码头轨迹规划和码头末端镇定靠泊两部分.基于大型船舶自身特点及限制等多约束分析的分阶段路径规划方法,完成面向大型商船自主靠泊的轨迹规划任务.考虑大型商船自身体型较大,低速运动时船舶的舵效和实船操纵性能差等难题,提出大型船舶自身限制等多约束分析的人工势场法,改进传统人工势场法中存在引力过大、目标不可达的问题.同时考虑镇定阶段船舶自身及泊位信息对船舶艏向和速度的约束,绘制舵角的输出变化曲线,并进行航迹规划,为商船选择合适的航线进行靠泊提供了理论依据.

智能船舶靠泊技术研究热点与趋势

在梳理近年来国内外智能船舶靠泊技术研究现状的基础上,首先从靠泊方式、数学模型和控制算法3个方面分别归纳靠泊技术的研究热点与应用情况,分析智能船舶靠泊技术在自主性、建模精度、路径规划、控制算法、节能效果和系统测试等方面尚待解决的问题。然后,从航海实际需求出发,提出下一步需要突破的有关信息融合、在线建模、智能决策、算法优化、绿色节能和测试技术等方面的核心理论和关键技术问题,努力提升靠泊技术的自主性、鲁棒性、快速性和“韧性”,助力实现安全、绿色、高效的智能航运目标。

基于AIS大数据耦合分析的沿海港口泊位利用率研究

针对我国沿海港口能力供给水平数据跟踪方面长期存在的时效性差、人为统计过程中易出现错漏等诸多问题,分析传统泊位通过能力统计失真的具体原因,提出将泊位利用率作为评价港口服务水平的表征指标,依托地理信息系统(GIS)平台和基于船舶自动识别系统(AIS)等数据耦合的空间拓扑分析,综合考虑空间关系、航速特征、经留时间等影响因素,研发基于AIS大数据的泊位利用率算法模型,并以上海港2019年集装箱泊位利用率为例进行算法验证。结果表明,所提出的泊位利用率算法模型是可信的;提供了一种能够反映客观实际、定量分析判断港口服务水平的技术手段,可为政府部门长期动态监测港口能力与运输需求互动平衡关系,支撑政府部门决策港口发展重点和建设时序,避免空间资源浪费、重复建设、能力过剩等问题提供技术支撑。

考虑占用率的大型停车库泊位动态分配模型

为提高驾驶员泊车效率,本文考虑不同停车库占用率下的停车库运营者及驾驶员泊位分配需求,构建大型停车库泊位分配模型。本文引入停车库占用率将停车库空满等级划分为空闲泊位充裕时段、空闲泊位适中时段、空闲泊位紧缺时段,综合考虑停车库运营者运营管理需求与驾驶员快速寻泊需求,以寻位行驶时间、离开停车库行驶时间为参数构建运营管理时间效用函数,以寻位行驶时间、停车入位耗时、步行时间为参数构建驾驶员泊车耗时效用函数;将运营管理时间效用与驾驶员泊车耗时效用加权统一为总时间效用,以总时间效用最大化为目标,建立兼顾停车库运营者及驾驶员泊位分配需求的泊位分配模型;引入泊位利用率、停车总耗时量化模型性能。以西安市某大型商业停车库为例,选取9:00、11:30、13:00表征空闲泊位充裕、空闲泊位适中、空闲泊位紧缺时段进行泊位分配。不同停车库空满等级下,停车库内空闲泊位的总时间效用与停车总耗时均呈负显著相关,其中,空闲泊位充裕时段,停车库内空闲泊位的总时间效用与停车总耗时的相关性最弱,相关系数为-0.461;空闲泊位紧缺时段,停车库内空闲泊位的总时间效用与泊位利用率呈正显著相关,相关系数为0.710。研究表明本模型可在优选停车总耗时较小泊位的基础上,为停车高峰时段预留利用率较高的泊位,提高空闲泊位紧缺时段的泊车效率及驾驶员的泊车满意度。

集装箱港口多码头泊位联合分配优化研究

多码头泊位联合分配是港口资源整合、提升服务水平的重要手段。针对集装箱港口多码头泊位计划,考虑不同码头泊位条件、岸桥能力等因素,构建多码头泊位-岸桥集成分配数学模型。设计改进灰狼算法(IGWO),利用离散化映射进行编码设计,基于优胜劣汰法实现种群动态进化。设计算例,将IGWO与果蝇算法和粒子群算法进行对比。结果显示:IGWO算法优化结果分别提升16.6%和21.1%;利用IGWO对不同船舶到港密度泊位算例进行求解,其中,多码头泊位分配可有效减少总时间成本及延误船舶数量,节省岸线资源约10%。结果表明:设计的模型及算法可有效解决多码头泊位联合分配问题。

深圳沿海某大型LNG码头平面设计要点分析

在国内LNG码头建设的新形势及新要求下,参照深圳沿海某大型LNG码头及陆域实际设计案例,采用规范和软件分析计算LNG码头泊位长度,并采用系泊物理模型试验进行验证及评估。通过现状及自然条件的分析,对陆域形成提出优化方案,并采用潮流泥沙数模试验分析等技术手段验证优化的陆域形态的合理性,同时对陆域形成的高程确定进行了系统分析。上述平面设计要点及技术问题的分析及解决方案,可为类似LNG码头以及陆域形成工程提供参考。