城市轨道交通电气系统网络负荷建模方法研究

城市轨道交通电气系统网络存在分散性、时变性、随机性、多样性和非连续性等多种特性。介绍了几种常用的经典负荷模型结构。针对该电气系统网络系统的特点,采用带有反馈模拟云数据生成器,应用隶属度函数与经典负荷模型相结合理论,提出一种基于窗函数的负荷模型建模方法,并对该方法进行了仿真验证。     

Patterns of motorization development and next-generation mobility systems

This paper discusses the appropriateness of the “3-stage urban transport policy development cycle” hypothesis proposed by Professor Peter Jones and the importance of both local development context and motorization transport culture in transport policy. It then makes some observations on the future prospects for sustainable cities and transport through major technological innovations in connected and autonomous vehicles, that is, in “Auto Sapiens” as next generation vehicles.     

基于Ecotect的T型交叉路口布灯方式仿真分析

为研究灯具布置对T型交叉口的照明影响,通过采用照明仿真软件对T型交叉口的交错式、对称式及中心对称式3种布灯方案进行仿真模拟分析,得到了不同布灯方式下的照明强度。结果表明:在相同灯具及条件下,交错式布灯方案最优,但道路终端灯光光强设置需偏大;对称式方案效果次之,交叉口中心位置照度低;中心对称式集中照明效果最好,但相比交错式及对称试其经济能耗最大。通过照明仿真模拟分析,有效验证了交错式布灯方案在T型交叉口照明设计中的优越性。     

A cluster analysis approach for differentiating transportation modes using Bluetooth sensor data

A variety of automatic data collection technologies have been used to gather road and highway system data. The majority of these automatic data collection technologies are designed to collect vehicle-based data and either do not have the capability to collect other travel mode data (e.g., bicycles and pedestrians), or may need to be deployed differently to support this capability.

One type of wireless-based data collection system that has been deployed recently is based on Bluetooth technology. A key feature of Bluetooth-based data collection systems that makes travel mode identification feasible is that the Bluetooth-enabled devices within vehicles are also present on bicyclists and pedestrians. This research explores the effectiveness of applying cluster analysis methods when processing data collected via Bluetooth technology from vehicles, bicyclists, and pedestrians to automatically identify the associated travel modes. The results of several experiments utilizing multiple Bluetooth-based data collection units arranged linearly and in relatively close proximity on a simulated intersection demonstrate the potential of cluster analysis to accurately differentiate transportation modes from the collected data.     

沉管隧道横向地基刚度分布模式初探

为解决沉管结构横向设计计算中的地基刚度取值问题,基于HS本构模型,通过理论推导研究地基刚度随应力水平的变化关系,得出沉管隧道横向地基刚度分布的近似解析解。结果表明： 1)沉管横向地基刚度分布模式与地基初始刚度、结构刚度、地基应力水平和上部荷载有关; 2)在软弱地基情况下,沉管横向地基刚度为W形分布模式; 坚硬地基情况下,底板跨中可能会与地基发生局部脱开,脱开段地基刚度为水平分布; 3)通过算例分析,地基刚度分布近似解析解与数值模拟结果能够较好地吻合,可为沉管结构计算提供依据。     

基于双层规划模型的地下综合管廊PPP项目入廊定价研究

为解决地下综合管廊项目PPP模式运作过程中存在的入廊定价难的突出问题,首先,基于现阶段入廊价格管制的需要以及各参与方在入廊定价决策过程中的主从递阶结构特点,决定利用双层规划模型研究PPP模式下地下综合管廊项目的入廊定价问题,将政府方作为定价决策的上层,社会资本方和管线单位作为决策的下层,建立政府、社会资本方与管线单位分别以社会福利最大化、预期收益最大化和保留效用最大化为目标的双层规划模型,以期求解得到令三方满意的入廊费、日常维护费与补贴额度。然后,以延安市地下综合管廊PPP项目为例,检验模型与求解方法的可行性。最后,基于研究结论提出加强顶层设计、强化价格监管、建立动态调价机制的合理化建议。     

基于CFD的三体船侧体布局阻力研究

三体船构型复杂,主体与侧体间的兴波干扰影响因素较多,很难通过理论方法对其阻力性能进行准确预报。采用软件STAR-CCM+模拟三体船周围粘性流场,对一艘三体船模进行数值计算。计算中进行了侧体、主体以及三体船9种不同侧体布局详细模拟,求出了侧体与主体间的兴波干扰值,得到较佳的布局方案。通过计算结果与模型试验对比分析,验证了计算的可靠性。     

基于双轴速率转台的IMU440惯性测量单元快速标定方法与实验

在捷联惯导系统中,惯性器件的确定性误差是系统误差的主要原因之一。为了提高惯导系统的输出精度,必须对这一误差加以补偿。以美国Crossbow公司开发的IMU440惯性测量单元为对象进行了快速标定实验,建立了陀螺仪和加速度计的误差模型方程,提出了用于辨识陀螺仪和加速度计误差模型参数的速率和位置标定法,根据两种标定方法得到了IMU440惯性测量单元的误差模型,最后对误差模型进行了校验。实验结果表明,误差补偿后的惯性器件输出值可以很好地接近理想输出值,大大降低了捷联惯导系统的输出误差。     

Experimental and numerical investigations on laser-welded corrugated-core sandwich panels subjected to air blast loading

Experimental investigations on the laser-welded triangular corrugated core sandwich panels and equivalent solid plates subjected to air blast loading are presented. The experiments were conducted in an explosion tank considering three levels of blast loading. Results show that the maximum deflection, core web buckling and core compaction increased as the decrease of stand-off distance. Back face deflections of sandwich panels were found to be nearly half that of equivalent solid plates at the stand-off distances of 100 mm and 150 mm. At the closest stand-off distance of 50 mm, the panel was found to fracture and fail catastrophically. Autodyn-based numerical simulations were conducted to investigate the dynamic response of sandwich panels. A good agreement was observed between the numerical calculations and experimental results. The model captured most of the deformation/failure modes of panels. Finally, the effects of face sheet thickness and core web thickness on the dynamic response of sandwich panel were discussed.     

欠驱动船舶路径跟踪的神经滑模控制

为实现欠驱动船舶在存在风浪流外界干扰和参数摄动条件下的路径跟踪控制,提出一种基于可视距离的神经滑模路径跟踪鲁棒控制器。利用可视距离思想,根据期望路径与当前位置信息,分别设计船舶纵向速度和艏摇角的参考值,并视为镇定位置误差的虚拟控制律,将路径跟踪问题转化为纵向速度和艏摇角的镇定问题;结合神经网络和滑模方法,设计一种新的神经滑模鲁棒控制器,实现了对虚拟控制律的跟踪控制,无需确定参数摄动和外界干扰的上界,避免了控制器容易出现的饱和问题和抖振现象。仿真试验表明,设计的控制器对欠驱动船舶的模型摄动和外界干扰变化不敏感,可以实现路径的理想跟踪。