多车超车跟车假想尾巴模型

进一步分析了各种传统方法在模拟超车跟车过程时存在的不足之处。以固支梁挠度曲线方程为基础,明确地提出了假想尾巴的新概念,它假定每一车辆有一假想的尾巴。各车的运动约束条件被表现为前方车辆尾巴和道路对其的联合作用,由此得到了一种用于模拟多车辆间超车和跟车过程的通用分析模型。在该模型中,为节约计算机时,车辆在道路的横向位置可暂不考虑而只对纵向位置独立计算。给出了具体算法和计算实例。该算法既能适用于两个或三个车辆的情形,也能适用于任意车辆及任意车辆初始位置的情形。该模型也被发现可用于事故模拟。     

基于LabVIEW和PLC的容量计量标准装置控制系统设计

依据JJG133—2005汽车油罐车容量检定规程,基于虚拟仪器软件LabVIEW和PLC,开发了一套汽车油罐容量计量标准装置控制系统,系统设计满足了计量标准装置对工业控制系统的特殊要求,实现了油罐车容量检定的自动化,提高了油罐车容量检定效率。     

基于电涡流传感器的车辆超速检测研究

车辆超速行驶是引发交通事故的重要因素。本文以单车道为例,在公路上相距一段距离埋设两个电涡流传感器,当汽车通过电涡流传感器时,产生脉冲信号,通过单片机编程对信号进行实时处理,最终得到汽车的行驶速度。实验表明,此方法可有效检测和记录各路段超速行驶的车辆,最终达到让驾驶员自觉遵纪守法、遵章驾驶和降低交通事故发生率,提高安全和畅通行车能力的目的。     

车辆远程监控系统的设计与实现

文章提出了一种具有实时安全预警功能的车辆远程监控系统,包括车载数据采集端、手机客户端以及监控中心.汽车车载数据采集终端可实时采集到车辆的位置信息、速度和加速度信息并通过3G无线通信网络将这些数据发送到监控中心数据服务器.监控中心接收到所有车辆传来的数据,并将信息发送到用户车的手机客户端上,手机客户端通过本车的数据和周边车辆的数据计算出本车是否处于安全状态,如不安全手机客户端则会预警,提醒驾驶员采取措施避免事故的发生.     

汽车电子自动限速系统的设计

文中介绍了以MSP430F149为控制器,以NRF2401为无线收发芯片的汽车自动限速系统。该系统能根据道路状况、天气、车型三种参数综合设定限速值,行车进入不同的路段,自动地改变限速值,司机无法更改。通过检测当前车速,并与限速值进行比较,当超速30S时,发出超速语言报警提示,并控制汽车油路,使车速保持在限速值附近,从而达到自动限制汽车行驶速度的目的。这将大大减少交通事故的发生。     

The “cognitive car”: A roadmap for research issues in the automotive sector

The numbers of cars on roads are increasing continuously. Consequently, streets and motorways are becoming more and more crowded and the risk of accidents is rising. In spite of the fact that in recent years cars have been made more efficient and capable, the driver behind the wheel is often overburdened with traffic situations. Therefore, scientists and engineers are challenged to develop a car which is safer and less stress-burdened than today. This paper outlines some future developments of such a more autonomous car within the next 15 years. The approach describes the roadmap for this “cognitive car” suggested by RWTH Aachen University.     

Car model recognition by utilizing symmetric property to overcome severe pose variation

This paper presents a mirror morphing scheme to deal with the challenging pose variation problem in car model recognition. Conventionally, researchers adopt pose estimation techniques to overcome the pose problem, whereas it is difficult to obtain very accurate pose estimation. Moreover, slight deviation in pose estimation degrades the recognition performance dramatically. The mirror morphing technique utilizes the symmetric property of cars to normalize car images of any orientation into a typical view. Therefore, the pose error and center bias can be eliminated and satisfactory recognition performance can be obtained. To support mirror morphing, active shape model (ASM) is used to acquire car shape information. An effective pose and center estimation approach is also proposed to provide a good initialization for ASM. In experiments, our proposed car model recognition system can achieve very high recognition rate (>95%) with very low probability of false alarm even when it is dealing with the severe pose problem in the cases of cars with similar shape and color.     

Estimation of Passenger Car Equivalents for single-lane roundabouts using a microsimulation-based procedure

Passenger car equivalents for heavy vehicles are required to carry out capacity calculations and perform operational analysis of any road entity (roadway segments or intersections). At single-lane roundabouts, the constraints to the vehicular trajectories imposed by the curvilinear geometric design and the driver's gap acceptance behaviour are expected to produce an impact of the heavy vehicles on the quality of traffic flow different from that produced on freeways and two-lane highways or other at-grade intersections. This is also because entering flow is opposed by the circulating flow which has priority and travels in an anticlockwise direction on a single-lane path around the central island.This paper addresses the question of how to estimate the passenger car equivalents for heavy vehicles on single-lane roundabouts. First, a comparison was performed between the empirical capacity functions based on a meta-analytic estimation of the critical and the follow up headways and the simulation outputs manually obtained for a single-lane roundabout built in Aimsun microscopic simulator. A genetic algorithm-based calibration procedure, therefore, was used to reach a better convergence between the simulation outputs and the empirical capacities. Based on the calibrated model, the passenger car equivalents were determined by comparing the capacity functions built for a fleet of passenger cars with the capacity functions calculated for different percentages of heavy vehicles. Differently from HCM 2010 which assumes a heavy vehicle to be equivalent to two passenger cars and sets as 2.0 the passenger car equivalents for heavy vehicles for roundabouts, a higher PCE effect would be expected on the quality of traffic conditions when the traffic stream contains a high number of heavy vehicles; this effect should be accounted for when calculating capacity and level-of-services.     

基于Adams的列车碰撞三维动力学模型和仿真

为研究列车碰撞性能,用Adams创建由车体、车钩缓冲装置、端部吸能结构、防爬器、转向架和轮轨力等组成的单节车厢三维动力学模型,并创建6节车厢列车的三维动力学模型,模拟列车以15 m/s的速度与2节静止车厢碰撞的过程.通过分析各节车厢的速度、加速度和每个车钩缓冲装置的相对偏移量在碰撞过程中的变化情况,重现列车碰撞过程,进而分析影响列车垂向爬车和横向屈曲稳定性的因素.仿真结果表明,碰撞过程中每个车钩缓冲装置的相对偏移量和列车各节车厢的加速度最大值均沿列车运行向不断变小;列车前三节车厢的垂向爬车和横向屈曲最严重,转向架发生出轨现象.     

受天气与交通事故影响的安全路线选择模型

为完善安全为第一因素的路线规划导航系统,突出“以人为本”的理念,基于OD（Origin-Destination）的路段选择,综合考虑贵阳市交通事故数据和天气数据两大影响线路风险系数的因素。建立泊松分布模型和马尔可夫模型,分析区域内交通事故易发点在晴天、阴天、雨天发生交通事故点概率和路线概率,构建风险系数指标。针对模型求得的路线安全系数采用最大决策法选出最优安全路线。结果表明,贵阳市不同天气下发生的交通事故频率有差异,检验每个地点发生交通事故数服从泊松分布;现有导航软件推荐的第一路线并不是最优路线,第二条路线才是安全系数最大的路线。基于泊松分布模型和马尔可夫模型计算交通事故发生概率,为现有导航软件中增添了安全系数为第一参考值的人性化设置,有较好的社会价值和推广性。     

A simulated annealing approach for the multi-periodic rail-car fleet sizing problem

In this paper, we proposed a new formulation and a solution procedure for optimizing the fleet size and freight car allocation wherein car demands and travel times are assumed to be deterministic and unmet demands are backordered. We assume that unmet demands become zero at the end of the planning horizon, i.e., the car demands are totally satisfied through the horizon. There are important interactions between decisions on sizing a rail car fleet and utilizing that fleet. Consequently, the optimum use of rail-cars for demands response in the length of the time periods is one of the main advantages of the proposed model. The model also provides rail network information such as yard capacity, unmet demands, and number of loaded and empty rail-car at any given time and location. Computational tests showed that small-size instances can be solved by the exact approach in a fair amount of CPU time, but it is not feasible for medium and large-size instances. To tackle this problem, a Simulated Annealing (SA) algorithm is proposed to solve the model. The algorithm works efficiently on a neighborhood search within solution space, acceptance probability, and inferior solutions to escape from trap (i.e., local optimal solution). Numerical examples are solved to check for the efficiency and validity of the SA algorithm.     

大型客车影响的双车道多速混合交通流CA模型研究

在对现有经典交通流元胞自动机模型进行总体分析的基础上,结合我国高速公路特点,通过重新标定元胞长度、运行车速、随机慢化机制,制定车道转换规则,构建了周期边界条件下考虑大型客车影响的双车道多速混合交通流元胞自动机模型,并通过计算机模拟分析了速度、密度、流量三参数之间关系,寻找出了大型客车占有率、大型客车随机慢化概率、变换车道车辆数等因素对交通流的影响规律,为合理的组织高速公路交通管理提供了理论依据。     

Redistributing stock in library systems with a depot

Public library organizations often utilize depots for carrying out shipments to libraries in case of stock-outs and for storing low demand rental items at low cost. Similar systems may be employed by rental companies for other rental products such as tools, DVDs, and jewelry. Since shipments deplete the depot’s inventory, stock must be taken back from the libraries in order to deal with future shipment requests. These shipment and take-back operations are carried out periodically, e.g. daily or weekly. This work focuses on optimizing the decisions for shipments and take-backs. We model the system by means of a Markov decision process and investigate its optimal policy for various problem instances. For the take-back decision, we distinguish between so-called threshold, reactive, and preventive take-backs. We use the insights from the MDP to develop a three-phase take-back heuristic. In experiments, our heuristic performs within 1% on average from the optimal solution. For settings with a large number of libraries, it is shown that an acceptable performance can be achieved by setting a base-stock level at the depot and taking back sufficient stock from the libraries to achieve this level.     

基于PLC的石油催化裂化车间安全巡检小车设计

在石油催化裂化车间安装固定传感器来检测车间环境的方案,受安装位置的限制存在监控盲区。开发一款安全巡检小车与原有的监测系统相结合,对降低车间发生事故的概率,有着直接而重要的作用。以一台基于PLC控制的巡检小车为载体,搭载多个气体检测传感器和ZigBee通讯模块。PLC与单片机相结合,控制小车自动巡航;使用EM235模块和气体传感器,监测车间环境状况;将环境数据通过ZigBee发送给上位机实时显示。当被测气体的浓度大于警戒值时,启动蜂鸣器和灯光报警。上位机采用C++Builder设计人机交互界面。通过测试表明,安全巡检小车与传统监测系统相结合可以更好地反映车间环境状态,提高监控效率。     

Directional control–response compatibility of joystick steered shuttle cars

Shuttle cars are an unusual class of vehicle operated in underground coal mines, sometimes in close proximity to pedestrians and steering errors may have very serious consequences. A directional control–response incompatibility has previously been described in shuttle cars which are controlled using a steering wheel oriented perpendicular to the direction of travel. Some other shuttle car operators are seated perpendicular to the direction of travel and steer the car via a seat mounted joystick. A virtual simulation was utilised to determine whether the steering arrangement in these vehicles maintains directional control–response compatibility. Twenty-four participants were randomly assigned to either a condition corresponding to this design (consistent direction), or a condition in which the directional steering response was reversed while driving in-bye (visual field compatible). Significantly less accurate steering performance was exhibited by the consistent direction group during the in-bye trials only. Shuttle cars which provide the joystick steering mechanism described here require operators to accommodate alternating compatible and incompatible directional control–response relationships with each change of car direction.

Practitioner Summary: A virtual simulation of an underground coal shuttle car demonstrates that the design incorporates a directional control–response incompatibility when driving the vehicle in one direction. This design increases the probability of operator error, with potential adverse safety and productivity consequences.     

基于物联网的AI交通管理系统——智能斑马线关键部分的设计与实现

随着人们生活水平的提高和日趋快速的现代化生活节奏，汽车几乎成了每家的必备出行工具，随之出现的就是交通事故数量的剧增。2018年最新交规新鲜出炉（不礼让行人扣3分，罚200元），由此可见人和车的矛盾始终存在。面对众多路口，不间断时间，仅依靠交警自身维持路口秩序，常常力不从心。本系统通过基于物联网的智能监测，对路人闯红灯行为进行自动监视和警告，结合语音提示，智能改变斑马线颜色等措施，在不需要人工介入的前提下实现行人过街的规范管理，减少行人闯红灯现象，降低交通事故发生概率，构建安全和谐的城市交通出行环境。     

Multi-route railroad blocking problem by improved model and ant colony algorithm in real world

In rail freight transportation, general merchandise freight cars may pass through many classification stations on their route from origin to destination. The Railroad Blocking Problem (RBP) is to reclassify inbound traffic from various origins in the classification stations and put them on outbound trains with the same or close destinations, the objective of the RBP is to minimize the total operating costs of delivering all traffic on the railway network while satisfying the resource and capacity constraints at the stations and the priority constraints for shipments. In this paper, we introduce a new mathematic model which can comprehensively describe the blocking strategy and various combinations of multi-route O–D pairs in large scale railway network. Furthermore, we propose an improved Ant Colony (AC) algorithm for RPB, and a computational experiment derived from the real life instances of coal heavy haul rail network in north China is given. Experimental results verified the validation of the model and effectiveness of the algorithm.     

优化模型在挤出吹塑工艺模拟中的运用

为减轻汽车塑料燃油箱的总质量,模拟挤出吹塑工艺中燃油箱的壁厚变化。将模拟问题分为3部分,即型坯长度优化、静态柔性变形板优化和垂直厚度分布系统优化。每个优化过程抽象为一个数学模型,在MATLAB中求解数学模型并获得最优解。优化结果与实际试验结果基本一致,产品总质量偏差小于3%,壁厚偏差小于7%,证明模拟方法合理。     

A hierarchical fuzzy system for modeling driver’s behavior

The study of human behavior during driving is of primary importance for improving the driver??s security. In this study, we propose a hierarchical driver_vehicle_environment fuzzy system to analyze driver??s behavior under stress conditions on a road. We include climate, road and car conditions in fuzzy modeling. For obtaining fuzzy rules, experts?? opinions are benefited by means of questionnaires on effects of parameters such as climate, road and car conditions on driving capabilities. The number of fuzzy rules is optimized by Particle Swarm Optimization (PSO) algorithm. Also the frequency of pressing on brake and gas pedals and the number of car??s direction changes are used to determine the driver??s behavior under different conditions. Three different positions are considered for driving and decision making; one position in driving lane and two positions in opposite lane. A fuzzy model called Model 1 is presented for modeling the change of steering angle and speed control by considering time distances with existing cars in these three positions, the information about the speed and direction of car, and the steering angle of car. The behaviors of different drivers under two stress conditions are investigated. Also we obtained two other models based on fuzzy rules called Model 2 and Model 3 by using Sugeno fuzzy inference. Model 2 has two linguistic terms and Model 3 has four linguistic terms for estimating the time distances with other cars. The results of three models are compared. The comparative studies have shown that simulation results are in good agreement with the real world situations.     

Railroad transportation of dangerous goods: Population exposure to airborne toxins

Hazardous materials are potentially harmful to people and environment due to their toxic ingredients. Although a significant portion of dangerous goods transportation is via railroads, prevailing studies on dangerous goods transport focus on highway shipments. We present an analytical framework that incorporates the differentiating features of trains, notably volume and nature of cargo, in the assessment of transport risk. We focus on hazardous materials that are airborne upon an accidental release into the environment. Each railcar is a potential source of release, and hence risk assessment of trains requires representation of multiple release sources in the model. We propose a risk approximation approach, which is not only effective but also robust with regards to the positioning of hazardous cargo in the train. We report on the use of the proposed approach for the assessment of population exposure associated with “Ultra-train” that passes through the city of Montreal everyday.