RANSE Simulation of High-speed Planning Craft in Regular Waves

This paper presents a study on the numerical simulation of planing crafts sailing in regular waves. This allows an accurate estimate of the seas keeping performance of the high speed craft. The simulation set in six-degree of freedom motions is based on the Reynolds averaged Navier Stokes equations volume of fluid （RANSE VOF） solver. The trimming mesh technique and integral dynamic mesh method are used to guarantee the good accuracy of the hydrodynamic force and high efficiency of the numerical simulation. Incident head waves, oblique waves and beam waves are generated in the simulation with three different velocities （Fn =1.0, 1.5, 2.0）. The motions and sea keeping performance of the planing craft with waves coming from different directions are indicated in the flow solver. The ship designer placed an emphasis on the effects of waves on sailing amplitude and pressure distribution of planing craft in the configuration of building high speed crafts.

Length optimization of straight line connecting turnout on main line in high-speed railway station yard

Taking the development of high-speed railway in China as background, and referring to the dynamic theory and wheel-rail contact mode, dynamic analysis model was established, considering the setting position of straight lines and running conditions of train in high-speed railway station yard. Using the established model, and choosing vehicle lateral acceleration and wheel suspension as the evaluation indexes, dynamic characteristic of vehicle traveling in turnout and adjacent area on main line was analyzed, and effects on travelling safety and stability of train aroused by length variation of straight lines were calculated based on analyzing the damping rules of vibration. The results show that, a certain length of straight lines can alleviate the vibration aroused in turnout and curve(turnout), length of straight lines connecting turnouts in different sections on main line was proposed to meet the demand of traveling stability, and shortening or cancelation of straight line for the scale limitation of station yard has less influence on operation safety of train.

Tool-path planning for free-form surface high-speed high-resolution machining using torus cutter

In CNC machining, two essential components decide the accuracy and machining time for a sculptured surface: one is the step-size interval, the other is the tool-path interval. Due to the limitation of the conventional method for calculating the tool-path interval, it cannot satisfy the machining requirement for high-speed and high-resolution machining. Accordingly, for high-speed and high-resolution machining, the current study proposes a new tool-path interval algorithm, plus a variable step-size algorithm for NURBS. Furthermore, a new type cutter, which can improve the cutting efficiency, is investigated in the paper. The transversal equation of the torus cutter onto the flat plan is given in this paper. The tool-path interval is calculated with the transversal equation and the proposed algorithm. The illustrated example shows that the redundant tool paths can be reduced because an accurate tool-path interval could be calculated.

Kinematical Analysis and Simulation of High-Speed Plate Carrying Manipulator Based on Matlab

In order to construct the more effective kinematics method for industry, by taking a high-speed plate handing robot as an example, the structure and parameters of the robot linkages are analyzed, and the standard Denavit-Hartenberg method is applied to establish the coordinates and the kinematic equation of the linkages. Depending on the graphics and matrix calculation ability of Matlab especially including the Robotics Toolbox, the handling robot has been modeled and its kinematics, inverse kinematics and the trajectory planning have been simulated. Therefore, the correctness of kinematic equation has been verified, meanwhile, the functions of displacement, velocity, acceleration and trajectory of all the joints are also obtained. In a further step, this has verified the validity of all the structure parameters and pro- vided a reliable basis for the theoretical research on the design, dynamics analysis and trajectory planning of the ma- nipulator control system.

AS/RS based yard and yard planning

In this paper, we apply the split-platform automated storage/retrieval systems (SP-AS/RSs) (Hu et al., 2005) to store containers in the yard to improve the yard performance and to increase the utilization of the yard space. The layout of an SP-AS/RS based yard is described in detail. To achieve an efficient operation, we present a novel yard space allocation policy called the ‘second-carrier-based allocation policy’, which can help to alleviate the out-of-sequence problem of containers and the congestion of vehicles at the AS/RS racks. Different allocation policies are compared by an integrated container terminal simulation system. The simulation results show that the second-carrier-based policy is very efficient and has the potential to offer high terminal performance.

Velocity Constraints Based Approach for Online Trajectory Planning of High‑Speed Parallel Robots

High-speed parallel robots have been extensively utilized in the light industry.However,the influence of the nonlinear dynamic characteristics of high-speed parallel robots on system’s dynamic response and stable operation cannot be ignored during the high-speed reciprocating motion.Thus,trajectory planning is essential for efficiency and stability from pick-and-place(PAP)actions.This paper presents a method for planning the equal-height pick-and-place trajectory considering velocity constraints to improve the PAP efficiency and stability of high-speed parallel robots.The velocity constraints in the start-and-end points can reduce vibration from picking and placing,making the trajectory more suitable to complex beltline situations.Based on velocity constraints,trajectory optimization includes trajectory smoothness and joint torque to optimize cycle time is carried out.This paper proposes an online trajectory optimization solution.By using back propagation(BP)neural networks,the solution is simplified and can be solved in real-time.Simulation and experiments were carried out on the SR4 parallel robot.The results show that the proposed method improves the efficiency,smoothness,and stability of the robot.This paper proposes an online trajectory planning method which is velocity constraints based and can improve the efficiency and stability of high-speed parallel robots.The work of this research is conducive to finely applying high-speed parallel robots.

Simulation Model Using Meta Heuristic Algorithms for Achieving Optimal Arrangement of Storage Bins in a Sawmill Yard

Bin planning (arrangements) is a key factor in the timber industry. Improper planning of the storage bins may lead to inefficient transportation of resources, which threaten the overall efficiency and thereby limit the profit margins of sawmills. To address this challenge, a simulation model has been developed. However, as numerous alternatives are available for arranging bins, simulating all possibilities will take an enormous amount of time and it is computationally infeasible. A discrete-event simulation model incorporating meta-heuristic algorithms has therefore been investigated in this study. Preliminary investigations indicate that the results achieved by GA based simulation model are promising and better than the other meta-heuristic algorithm. Further, a sensitivity analysis has been done on the GA based optimal arrangement which contributes to gaining insights and knowledge about the real system that ultimately leads to improved and enhanced efficiency in sawmill yards. It is expected that the results achieved in the work will support timber industries in making optimal decisions with respect to arrangement of storage bins in a sawmill yard.

A two-layer optimization model for high-speed railway line planning

Line planning is the first important strategic element in the railway operation planning process,which will directly affect the successive planning to determine the efficiency of the whole railway system.A two-layer optimization model is proposed within a simulation framework to deal with the high-speed railway (HSR) line planning problem.In the model,the top layer aims at achieving an optimal stop-schedule set with the service frequencies,and is formulated as a nonlinear program,solved by genetic algorithm.The objective of top layer is tominimize the total operation cost and unserved passenger volume.Given a specific stop-schedule,the bottom layer focuses on weighted passenger flow assignment,formulated as a mixed integer program with the objective of maximizing the served passenger volume andminimizing the total travel time for all passengers.The case study on Taiwan HSR shows that the proposed two-layer model is better than the existing techniques.In addition,this model is also illustrated with the Beijing-Shanghai HSR in China.The result shows that the two-layer optimization model can reduce computation complexity and that an optimal set of stop-schedules can always be generated with less calculation time.

Energy-efficient receding horizon trajectory planning of high-speed trains using real-time traffic information

Optimal trajectory planning of high-speed trains(HSTs)aims to obtain such speed curves that guarantee safety,punctuality,comfort and energy-saving of the train.In this paper,a new shrinking horizon model predictive control(MPC)algorithm is proposed to plan the optimal trajectories of HSTs using real-time traffic information.The nonlinear longitudinal dynamics of HSTs are used to predict the future behaviors of the train and describe variable slopes and variable speed limitations based on real-time traffic information.Then optimal trajectory planning of HSTs is formulated as the shrinking horizon optimal control problem with the consideration of safety,punctuality,comfort and energy consumption.According to the real-time position and running time of the train,the shrinking horizon is updated to ensure the recursive feasibility of the optimization problem.The optimal speed curve of the train is computed by online solving the optimization problem with the Radau Pseudo-spectral method(RPM).Simulation results demonstrate that the proposed method can satisfy the requirements of energy efficiency and punctuality of the train.

装配式桥梁预制梁生产与安装智能规划系统研究与应用

目前,装配式桥梁预制梁的生产与安装规划主要依靠人工经验进行,但由于影响因素较多,人工编制的规划容易出错,从而影响工期,且行业内尚无成熟工具支持。因此,通过对装配式桥梁预制梁生产与安装进度所涉及的影响因素、供求平衡关系进行分析,并将人工经验用逻辑的方式进行表达,为预制梁生产与安装规划建立算法,开发成预制梁生产与安装智能规划系统。该系统可辅助项目管理人员快速进行预制梁生产和安装规划,并可结合现场实际情况进行动态调整,实现预制梁在生产、存储和安装过程中的智能化管控。

列控车载设备不同工作模式下运行方案研究

针对高铁动车组列车进出动车段(所、存车场)的不同运营场景,对动车存车场内岔区侧向允许通过速度低于列控车载设备顶棚限制速度导致的列车紧急制动等问题进行了研究。通过对典型动车存车场内站场布置方案、道岔号码选择、信号系统设置情况进行分析,结合动车组列车进出动车存车场的特殊运营场景,分析了CTCS-2级列控车载设备在不同工作模式下存在的运行风险,即动车存车场内设置9号道岔时其侧向允许通过速度会对列车安全运行造成影响。在此基础上,根据新建和既有动车段(所、存车场)的不同情况提出了两种优化方案,优化后的方案已在部分工程中进行了应用,同时也为后续铁路的工程设计、运营维护提供了借鉴。

BIM在高铁梁场临建过程中的应用

高铁梁场规划设计以安全适用、技术先进、经济合理、环保为原则,统筹规划设计,以达到制梁速度快、质量高、建场费用低、节约用地的目标。文章以平漯周高铁商水梁场为例,详细阐述BIM技术在梁场临建前期规划设计中的综合应用。

自动化码头单悬臂场桥调度与AGV路径规划

为提高单悬臂场桥与自动导引车(AGV)协同作业效率,针对双单悬臂场桥调度和AGV路径规划问题,构建两阶段优化模型。第一阶段以最大完工时间最少为优化目标建立模型,优化AGV停车位和双单悬臂场桥调度,设计遗传模拟退火算法求解;第二阶段根据第一阶段得到的AGV停车位置及时间信息,首先在不考虑AGV冲突的情况下采用改进的Dijkstra算法求解AGV初始路径,然后采用混合冲突解决策略解决箱区内AGV冲突问题。以上海洋山四期自动化码头为背景设计算例,用CPLEX验证模型准确性,通过与其他算法的比较验证了算法的有效性。结果表明,所建模型和提出的策略能有效提高单悬臂场桥和AGV的工作效率。

武宣县高达水库枢纽工程土石方平衡分析

土石方平衡是生产建设项目的重要环节,关系到料场及弃渣场的选择,直接影响工程投资。以广西武宣县高达水库枢纽工程为例,分析了土石方挖填量的计算、临时堆土场的规划、料场选择和弃渣的综合利用等内容,并对各方案进行了评价。评价结果显示,该工程的土石方调配方案以及水土流失防治措施在保证工程顺利建设的前提下,还具有良好的经济效益和生态效益。

苏州苏纶场工业街区更新活化策略探讨

城市中的工业遗产是城市文化遗产的重要组成部分,它见证了城市文明与人类发展的进程,加强工业街区的整治与保护是城市更新工作的关注重点。文章以苏州苏纶场为例,通过梳理街区发展历史变迁和深入调研街区交通、景观、功能等方面的现状问题,从交通梳理、景观营造、功能植入三个层面探讨街区活力提升的策略,以期为相关城市工业街区更新规划设计提供参考。

基于LINGO的水利工程料场规划方案设计研究

水利工程料场规划中的运输问题是很多管理者忽视的问题,大多仅凭经验确定调运方案。采用运筹学中关于运输问题的定量方法,引用工程案例从路线规划的角度进行优化建模,研究水利工程料场规划中的运输问题,并利用LINGO软件求解最优解,从而科学化和定量化地辅助决策者做出最优决策。

CTC3.0系统一站多场计划劈分和报点整合方案实现与应用

针对CTC3.0系统实施推广过程中,一站多场类型车站列车运行计划无法精准拆解和报点不对应等问题,提出解决方案。依托济南站实际应用场景,结合客货车在多场间到发线运用现状,分析车站终端和中心调度台报点管理需求,明确列车运行计划劈分规则,构建中心调度台与车站多场间站号、股道、方向口转换关系,提出列车运行计划劈分和报点整合处理方法,并通过技术作业图表展示相关信息。经验证,该方法有效解决了一站多场计划精细化管理和不同终端报点整合问题,提升了济南站行车指挥作业效率,降低了车站作业人员的工作强度,为一站多场车站应用CTC3.0系统提供借鉴。

生态型农业观光园规划设计

通过阐述园区规划设计原则及理论根据,结合实例分析了生态型农业观光园的设计内容,有利于更好的研究与开发农业观光园项目。

集装箱堆场作业计划模型及算法

寻求能够自动生成集装箱堆场作业计划的方法,使得堆场的使用及作业更为合理有序。首先,进行堆场集装箱集合的划分,得到静态码垛模型,通过箱大区和箱小区解决半自由箱和非自由箱问题及堆场碎片问题。其次,定义集装箱码放顺序的全序关系,得到动态码垛模型,并设计求解该模型的箱小区判定算法和单箱码箱取箱算法。引入动态全序概念,说明动态全序构造方法。结合取箱时空箱位的暂扣问题,得到循环箱码垛模型,设计循环箱单箱码箱取箱算法,及构造动态全序算法和暂扣标记设置解除算法。再次,分析一个作业计划派工单中各个作业之间的部分序关系。最后,算例表明循环箱码垛模型及相应算法能够适应集装箱堆场上频繁码箱取箱作业,整体上看箱位使用频率基本均衡,并且呈现循环滚动使用态势。

热轧板坯库出库计划编制模型与算法研究

为了解决板坯库出库计划的编制问题,提出了将板坯库出库计划分解为板坯出库优化决策和板坯最优倒垛决策组合优化问题,分别建立了板坯出库优化决策模型和板坯最优倒垛决策模型,利用两个模型分层协作完成出库计划的编制。为求解模型,构造了一种离散粒子群优化算法,采用适合模型的粒子取值方式和粒子速度变化方式。实际排产的结果表明,所建立的模型和算法切实可行。