载货汽车主气瓶不同气压时制动性能分析

汽车综合性能测试仪VGQT测试分析结果表明,货车在主制动气瓶压力不同时,各轴制动气室所能达到的最大压力也不相同[1],除此之外,本试验中N类载货汽车0型制动试验表明,主气瓶气压不同时,各轴气室制动压力变化曲线以及有效最大减速度MFDD也不相同。载货汽车绝大部分是用于长途运输,尤其是N2、N3类载货汽车,由于其满载质量大,长途运输中制动效能对于行驶安全性有着很大的影响,尤其在我国西南部山道纵横,长时间上下坡很容易造成制动器的热衰退,这是引起交通事故的主要诱因之一[2,3]。本文以实际试验结果为研究对象,分析了主气瓶在不同压力下各轴制动气室压力的变化以及0型制动试验中制动气压曲线的变化和有效最大减速度的变化,这对于行驶安全性和燃油经济性都有一定的意义,进而对排放和环境造成影响。     

隧道及地下工程远程自动化监测与预警系统构建研究

基于Python编程语言和大数据，构建可实现工程监测、综合预警、可视化、参数反演及实时动态分析等功能的自动化监测预警系统。该自动化监测预警系统可对施工过程中岩土体压力、位移、渗透水压等进行实时监测，并自动采集监测数据进行远程无线传输，自动存储到数据库中，借助互联网云平台进行数据共享；监测数据可供IA-BP算法模块、预警预报模块调用，采用IA-BP智能算法对数据库内监测数据进行反演及智能预测分析，并进行单项阈值和IA-BP智能算法综合对比分析，达到工程灾害预警预报目的。     

基于收费站交通量及视频分析技术监测拥堵研究

随着我国汽车保有量的不断增长,高速公路收费站车辆拥堵的瓶颈问题越来越突出,对高速公路收费站的车辆拥堵情况及放行速度进行监测,对疏导交通、节约能源消耗及减少尾气排放有着重要的意义。本文从微波检测交通量及视频分析两个方面,阐述了利用交通量监测收费站车辆拥堵原理,利用智能视频技术自动对收费站车道上的车辆通行密度进行自动监测和预警。     

道路运输车辆动态监督管理办法

<正>第一章总则第一条为加强道路运输车辆动态监督管理,预防和减少道路交通事故,依据《中华人民共和国安全生产法》、《中华人民共和国道路交通安全法实施条例》、《中华人民共和国道路运输条例》等有关法律法规,制定本办法。第二条道路运输车辆安装、使用具有行驶记录功能的卫星定位装置(以下简称卫星定位装置)以及相关安全监督管理活动,适用本办法。第三条本办法所称道路运输车辆,包括用于公路营运的载客汽车、危险货物运输车辆、半挂牵引车以及重型载货汽车(总质量为12吨及以上的普通货运车辆)。     

不同车型FCW试验中TTC安全时间阈值分析

目前,在自动驾驶车辆技术中已实现量产的功能主要分布于L0-L2 (SAE标准)阶段,其中主要功能以前向碰撞预警(FCW)、车道偏离预警(LDW)、自适应巡航(ACC)以及紧急制动(AEB)等为主;针对前向碰撞预警(FCW)功能技术,目前的测试方法主要依据美国公路交通安全管理局(NHTSA)、欧盟(EU)以及国际标准化组织(ISO)制定的《FORWARD COLLISION WARNING SYSTEM CONFIRMATIONG TEST》、《ISO15623 Transport information and control systems-Forward vehicle collision warning systems-Performance Requirements and Test Procedures》等相关标准;而类似标准在设置TTC规避阈值时间(即安全碰撞时间)均设置为固定值,没有依据不同类型车辆设相关加权系数。本文根据不同车型的多次FCW试验发现,为了保证试验安全,汽车质量和TTC存在一定的相关性。本文依据不同类型车辆制动试验数据计算出相关系数,从而界定了安全的TTC阈值。     

分布式光纤测温系统在铁路隧道中的应用

文章基于分布式光纤测温系统的特点,结合成渝客专元宝山隧道温度监测示范工程研究实例,对该监测系统的设备选型、安装进行了分析说明,并通过点火试验对该监测系统的实际效果进行了验证。结果表明,该系统可进行连续、动态、实时的温度监测,能有效预警和准确定位火灾发生,达到火灾灾情监测的目的,为抢险救护及灾情评估提供科学依据。     

基于TruckSim的重型清障车操纵稳定性分析

国内清障车主要使用的是载货汽车的二类汽车底盘,这种底盘在整车的结构布置和承力方式上有许多不满足清障车专用作业装置的布置需求。本文以重型清障车的操纵稳定性为研究目标,基于TruckSim软件建立某款重型清障车工程样车的整车模型,参照《GB/T 6323-2014汽车操纵稳定性试验方法》对汽车进行稳定性仿真试验,选取不同质心高度和质心纵向位移进行开环评价和闭环评价对比分析。结果表明在原设计参数的基础上降低车辆的质心高度和前移质心纵向位移,对车辆的操纵稳定性具有一定的提高。     

PID在汽车防抱死系统中的仿真应用

本文通过数学建模建立了车辆动力学模型、滑移率模型、制动系统模型、轮胎模型、PID控制器等主要模型,然后建立了基于二轮车辆无ABS系统仿真模型、有PID控制器仿真模型,接着分别在高附着系数路面、低附着系数路面和对接路面上进行仿真试验。将三种不同车辆系统的制动时间、制动距离以及车轮是否抱死等性能参数进行对比分析,结果表明无ABS系统的车辆无论在哪种路况下制动,车轮均很快抱死,且制动时间最长,制动距离最大;有PID控制器的车辆可以使车轮滑移率在较短的时间内稳定在最佳滑移率处,避免了车轮抱死,制动距离与制动时间相比无ABS车辆都有明显改善。     

某在役桥梁健康监测多级挠度预警阈值设定分析

为实现桥梁的健康监测和自动预警,依托实际工程,结合桥梁监测系统,通过分析温度与挠度之间的关系,将实际监测的竖向位移数据和竖向位移-温度的回归方程进行比较,得到桥梁在车辆荷载作用下的挠度值。结合桥梁结构特性以及有限元计算结果,设定多级桥梁竖向位移预警阈值,为桥梁结构长期安全运营提供准确、可靠的预警信息。     

发动机变功率配气机构的节能性研究

随着我国经济的飞速发展,汽车节能技术日益重要。为了合理利用汽车在减速滑行状态下的动能,本文提出了一种发动机变功率配气机构,具体指汽车在减速滑行状态下,控制发动机不喷油,同时排气门释压,减小发动机制动阻力,充分利用汽车惯性能量滑行更远的距离,以达到汽车节能减排的目的;并基于此原理对改装过的汽车做挂档滑行距离对比试验和车辆油耗对比试验,结果表明改装车辆节油率达7.72%,节油效果明显,具有推广应用的实际价值。     

汽车AFS系统垂直方向上车灯调整角度的规律研究

本文研究汽车AFS系统在垂直方向上的转角原理,包括车辆重心的变化对前大灯照射距离的影响,车辆俯仰角的变化对前大灯照射距离的影响,最终得到垂直方向上车灯调整角度的规律。     

Designing a sliding mode controller for slip control of antilock brake systems

Antilock brake system (ABS) has been designed to achieve maximum negative acceleration by preventing the wheels from locking. Research shows that the friction between road and tire is a nonlinear function of wheel slip. Therefore, maximum negative acceleration can be achieved by designing a suitable control system for wheel slip regulation at its optimum value. Since there is a lot of nonlinearity and uncertainty (uncertainty in mass and center of gravity of the vehicle and road condition) in vehicle dynamics, a robust control method should be used. In this research, a sliding mode controller for wheel slip control has been designed based on a two-axle vehicle model. Important considered parameters for vehicle dynamic include two separated brake torques for front and rear wheels as well as longitudinal weight transfer caused by the acceleration or deceleration. One of the common problems in sliding mode control is chattering phenomenon. In this paper, primary controller design has been improved using integral switching surface to reduce chattering effects. Simulation results show the success of integral switching surface in elimination of chattering side effects and by high performance of this controller. At the end, the performance of the designed controller has been compared with three of the prevalent papers results to determine the performance of sliding mode control integrated with integral switching surface.     

Assessing the impact of reduced visibility on traffic crash risk using microscopic data and surrogate safety measures

Due to the difficulty of obtaining accurate real-time visibility and vehicle based traffic data at the same time, there are only few research studies that addressed the impact of reduced visibility on traffic crash risk. This research was conducted based on a new visibility detection system by mounting visibility sensor arrays combined with adaptive learning modules to provide more accurate visibility detections. The vehicle-based detector, Wavetronix SmartSensor HD, was installed at the same place to collect traffic data. Reduced visibility due to fog were selected and analyzed by comparing them with clear cases to identify the differences based on several surrogate measures of safety under different visibility classes. Moreover, vehicles were divided into different types and the vehicles in different lanes were compared in order to identify whether the impact of reduced visibility due to fog on traffic crash risk varies depending on vehicle types and lanes. Log-Inverse Gaussian regression modeling was then applied to explore the relationship between time to collision and visibility together with other traffic parameters. Based on the accurate visibility and traffic data collected by the new visibility and traffic detection system, it was concluded that reduced visibility would significantly increase the traffic crash risk especially rear-end crashes and the impact on crash risk was different for different vehicle types and for different lanes. The results would be helpful to understand the change in traffic crash risk and crash contributing factors under fog conditions. We suggest implementing the algorithms in real-time and augmenting it with ITS measures such as VSL and DMS to reduce crash risk.     

多功能管道内检测器测试平台研制

针对管道内检测技术开发方法存在的不足,设计了一种多功能管道内检测器开发测试平台,提高了管道智能检测技术相关的元件开发测试的效率。按照实验思路设计不同的检测单元,可以实现多种管道智能检测技术相关元器件的测试,操作方便、节省时间和成本。实验表明,该平台能较好地完成MBN检测信号的采集。     

Adapt-Traf: An adaptive multiagent road traffic management system based on hybrid ant-hierarchical fuzzy model

Usually, road networks are characterized by their great dynamics including different entities in interactions. This leads to more complex road traffic management. This paper proposes an adaptive multiagent system based on the ant colony behavior and the hierarchical fuzzy model. This system allows adjusting efficiently the road traffic according to the real-time changes in road networks by the integration of an adaptive vehicle route guidance system. The proposed system is implemented and simulated under a multiagent platform in order to discuss the improvement of the global road traffic quality in terms of time, fluidity and adaptivity.     

Simulator evaluation of incident detection by transponder-equipped vehicles

This paper explores the efficacy of the driver-based incident detection using the vehicle-to-roadside communication (VRC) system. The proliferation of vehicle tags in the US for automatic toll collection, traffic monitoring, and vehicle navigation and information systems has created an infrastructure capable of supporting a driver-based incident detection system. The research reported herein investigated the use of "activatable" vehicle tags by drivers to send an incident signal to the Traffic Management Center through VRC reader stations spaced uniformly on a highway. The simulation results showed that good detection performance was achieved even at lower levels of market penetration of vehicle tags. The results further showed that detection performance is significantly affected by the severity of the incident in terms of number of lanes closed, the spacing of the VRC reader stations, traffic volume at the time of the incident, and the reporting propensity of the traveling public.The performance of the VRC-based incident reporting system was compared to the performance of two incident detection algorithms that rely on traffic data collected through the automatic vehicle identification (AVI) system. The comparison showed that the VRC-based incident reporting system attained shorter detection times and higher detection rates under fairly similar simulated conditions. The paper also discusses issues that need further study through simulation and field experimentation of the VRC-based incident reporting system.     

基于GSM下管道流量泄漏监测与定位系统

针对管道泄漏,设计了基于GSM 下远程泄漏监测与定位系统,由管网监测终端实时采集管网流量、流速、流向和压力,通过GPRS网络实现远程数据传输;系统基于GIS技术构建,针对管网突发性的爆管和地下泄漏特点,综合运用了负压波和流量检测法进行泄漏模式识别与漏点定位,可及时、准确地发现和定位泄漏点.     

The development of taiwan arterial traffic‐adaptive signal control system and its field test: A taiwan experience

This Taiwan traffic‐adaptive arterial signal control model borrowed its traffic flow framework mainly from a British traffic‐adaptive control model with a cyclic traffic progression function, i.e. SCOOT (Split Cycle Office Optimisation Technique). The new arterial control model can take into account delays of both major and minor streets and make real‐time signal timing decisions with optimal two‐way signal offsets, so as to create the best arterial signal operation performance. It has been developed to be an online real‐time software for both simulation testing and field validation. Through simulation, it was found that the performance when operating this newly developed real‐time arterial traffic‐adaptive model was significantly better than when using the optimal fixed‐time arterial timing plan. On the aspect of field testing, three signalized intersections located in East District, Tainan City, Taiwan were selected to be the test sites. Fairly good traffic control performance has been demonstrated in that it can effectively reduce travel delays of the control arterial as a whole. Additional discussions about how to combine travel delay and the total number of vehicle stops into a new control performance index have also been included to make the new traffic‐adaptive model more flexible and reasonable to meet the expectations of different driver groups in the arterial system.     

基于碳平衡原理的天然气汽车燃料消耗量检测方法研究

文章通过分析天然气组份及天然气发动机的燃烧特性,基于碳平衡原理建立了天然气汽车燃料消耗量计算模型。对比分析了闭式和开式碳平衡检测系统的结构工作原理及适用范围,确定采用开式稀释采样方式进行天然气燃料消耗量检测系统开发。结合天然气汽车燃料消耗量计算模型中的技术参数需求,设计开发了碳平衡气耗仪。为了分析设备工作的可靠性和测量的准确性,选用LNG宇通客车和东风危险品运输车作为试验样车,利用科里奥利质量流量计对其进行标定。通过对比试验可知,碳平衡气耗仪与科里奥利质量流量计相对误差为5%,基本满足在用天然气汽车燃料消耗量检测的需求。