Integrated optimization of bus priority operations in connected vehicle environment

Most previous works associated with transit signal priority merely focus on the optimization of signal timings, ignoring both bus speed and dwell time at bus stops. This paper presents a novel approach to optimize the holding time at bus stops, signal timings, and bus speed to provide priority to buses at isolated intersections. The objective of the proposed model is to minimize the weighted average vehicle delays of the intersection, which includes both bus delay and impact on nearby intersection traffic, ensuring that buses clear these intersections without being stopped by a red light. A set of formulations are developed to explicitly capture the interaction between bus speed, bus holding time, and transit priority signal timings. Experimental analysis is used to show that the proposed model has minimal negative impacts on general traffic and outperforms the no priority, signal priority only, and signal priority with holding control strategies (no bus speed adjustment) in terms of reducing average bus delays and stops. A sensitivity analysis further demonstrates the potential of the proposed approach to be applied to bus priority control systems in real‐time under different traffic demands, bus stop locations, and maximum speed limits. Copyright © 2016 John Wiley & Sons, Ltd.     

基于 GT-Crank 仿真的柴油机气缸磨损时瞬时转速分析

利用 GT‐Crank 软件对柴油机曲轴瞬时转速进行仿真分析计算,研究了正常状态、单缸磨损、多个相邻缸磨损和多个非邻缸磨损状态下瞬时转速的变化规律,提取了状态特征参数,并分析了气缸磨损对其他缸的影响,为深入研究瞬时转速在柴油机状态检测诊断中的应用提供了理论依据。     

Connected variable speed limits control and car-following control with vehicle-infrastructure communication to resolve stop-and-go waves

The vision of intelligent vehicles traveling in road networks has prompted numerous concepts to control future traffic flow, one of which is the in-vehicle actuation of traffic control commands. The key of this concept is using intelligent vehicles as actuators for traffic control systems. Under this concept, we design and test a control system that connects a traffic controller with in-vehicle controllers via vehicle-to-infrastructure communication. The link-level traffic controller regulates traffic speeds through variable speed limits (VSL) gantries to resolve stop-and-go waves, while intelligent vehicles control accelerations through vehicle propulsion and brake systems to optimize their local situations. It is assumed that each intelligent vehicle receives VSL commands from the traffic controller and uses them as variable parameters for the local vehicle controller. Feasibility and effectiveness of the connected control paradigm are tested with simulation on a two-lane freeway stretch with intelligent vehicles randomly distributed among human-driven vehicles. Simulation shows that the connected VSL and vehicle control system improves traffic efficiency and sustainability; that is, total time spent in the network and average fuel consumption rate are reduced compared to (uncontrolled and controlled) scenarios with 100% human drivers and to uncontrolled scenarios with the same intelligent vehicle penetration rates.     

设计时速 160 km 以下铁路隧道（普货、有砟轨道）内轮廓标准研究

当前运营的时速160 km以下有砟轨道（普货）隧道内轮廓尽寸难以满足大型养护机械（特别是大型清筛机）作业空间需求,通过对新建时速160 km以下电气化铁路、单双线隧道内轮廓主要影响因素（建筑限界、接触网悬挂方式及布置、大型养护机械空间需求、轨道结构型式、侧沟及电缆槽设置等）进行综合分析,确定单双线有砟轨道隧道内轮廓控制性尺寸,并初步拟定满足大型养护机械作业要求的内轮廓方案,在此基础上通过对内轮廓方案的结构安全性、经济性及施工便利性进行综合比较,确定推荐方案,该成果对铁路行业隧道通用图编制有一定的参考价值。     

欧曼组合仪表拨码器

介绍欧曼汽车仪表设计中的拨码器,阐述其原理、结构、性能参数、软硬件电路及特性,用实例来说明拨码器的调整。     

降速报警防追尾系统的设计应用

根据车辆的行驶状态和制动降速时制动灯工作延迟时间,作者开发了降速防追尾系统。可提前控制制动灯工作以提醒后方驾驶员注意安全,以降低安全隐患。     

沥青路面摊铺离析评价方法研究

针对沥青路面摊铺离析导致路面出现早期损害和平整度衰减的问题,将摊铺路面分为多个检测道,借鉴ASTM(American Society for Testing and Materials)比对试验分析方法,视摊铺机在各检测道的摊铺行为为独立试验过程,采用无核密度仪和激光纹理仪两种无损检测手段,通过对沥青路面内部空隙率和表面构造深度均匀性分析来评价路面横、纵向摊铺离析,在检测试验结果的分析上,引入重复性标准偏差Sr、SR和一致性统计量k、h作为评价分析手段,并运用取芯切片及结合数字图像处理的方法来分析芯样截面的面空隙率差异,能有效评价沥青路面的竖向离析。结果证明,这种评价方法很好地反映了沥青路面施工质量的均匀性,该方法切实可行。     

汽车空调风机无刷直流双模糊PI调节的无级调速系统研究

研究的对象是汽车空调风机的无级调速系统,该系统采用双闭环控制,内环和外环都采用模糊PI控制策略。通过对仿真结果的分析,表明模糊PI控制优于传统的PI控制,证明了该无级调速系统仿真模型的正确性。     

高速公路减速标线的设计与应用研究

由于在我国现有规范中没有统一的减速标线设计应用标准,导致在高速公路上设置减速标线难以达到管理控制及保障安全的目的。针对这种情况,必须使用实用性高、针对性强的设计方案,并使之人性化、科学化、规范化,才能更好地保证道路交通安全。     

线程安全队列技术在交流电机调速系统中的应用

介绍了数据保护的概念和原理,根据交流电机调速系统的要求,使用线程安全队列技术对电机的数据进行保护,以期能正确反映电机的运行情况.通过实验,对使用线程安全队列技术的效果进行了验证.