考虑前后多车的网联自动驾驶车辆混流跟驰模型

随着中国新基建战略的提出及自动驾驶和网联通信技术的不断发展，网联自动驾驶车辆（CAV）、自动驾驶车辆（AV）和常规人驾车辆混行的交通流将在未来长时间存在。建立适用于网联自动驾驶车辆、自动驾驶车辆和常规人驾车辆3种类型车辆的混流跟驰模型，考虑多前后车车头间距、多前车速度差、加速度差、与主体车辆的相对距离等因素，并进行典型场景的数值仿真。刹车和起步过程的3种混流数值仿真结果显示，模型在几种典型混行场景下均具有可行性，车辆的加速度和速度变化更为平缓。不同CAV比例下的数值仿真结果显示，车队中CAV比例越高，车队整体恢复至平稳状态的时间越短，波动幅度越小。CAV均质流数值仿真结果表明，与MHVAD模型相比，该模型不稳定区域减小33.8%，所控制的车队速度波动幅度减小14%。CAV与AV混流的数值仿真结果显示，与PATH实验室模型相比，由该模型控制的车队加速度进入相对稳定状态提前5.5 s。该模型可用于不同车辆均质流及3种车辆混行的队列控制，在目前开展混行实车试验困难的情况下，也可应用该模型进行混行跟驰仿真，从而为混行交通流的道路交通管理及基础设施布设提供理论依据和模型支持。     

钢混叠合式梁拱组合桥设计

鄂尔多斯市东胜区苏杨公路一号桥上跨包茂高速公路,桥型采用三跨连续的钢混叠合式梁拱组合桥,跨径组合为35m+90m+35m。该桥设计充分考虑施工方式对下穿包茂高速公路的影响及景观因素,主梁采用工厂节段加工、现场焊接的钢梁格,通过剪力钉连接预制混凝土桥面板;拱肋为钢箱结构,由上、下肢拱通过刚性竖杆连缀而成,焊接于钢系梁顶面。整幅桥全宽50m,两拱肋中心间距33m,不设风撑,为国内整幅最宽的钢混叠合式梁拱组合桥。就此对该桥的结构设计特点、构造与施工要点等进行了简要介绍。     

GPS-based optimization of plug-in hybrid electric vehicles’ power demands in a cold weather city

Using the WPG03 duty cycle developed from global positioning data collected in Winnipeg, Canada, real world energy demands and costs are modeled. Three types of plug-in hybrid electric vehicles, four temperatures and two charging scenarios are compared to a vehicle with an internal combustion engine. Cold temperatures are shown to greatly affect vehicle operation energy costs, which is an important consideration for cold weather cities such as Winnipeg. The largest energy cost savings are obtained for smaller-battery plug-in hybrids that had the opportunity to charge during the day.     

基于多属性决策运输车编配方案研究

在信息化战争中,后勤运输保障举足轻重。根据部队运输需求,制定出科学合理的运输车编配结构对于提高部队公路运输保障能力具有重要的指导意义。分析了我军运输车编配存在的问题,介绍了基于最大离差化的多属性决策模型,为运输车编配方案评价提供了一种合理的研究方法。并以某摩步师直属汽车营为例,对运输车的备选方案进行了排序和选优,得到了...     

网联环境下混合交通流偶发拥堵演化机理研究

针对混合交通流中智能网联车辆(Connected and Autonomous Vehicles, CAVs)和人工驾驶车辆的交织干涉问题,本文在传统交通流统计理论模型和一阶连续介质模型的基础上,通过引入智能驾驶员跟驰模型(Intelligent driver model, IDM)和协同自适应巡航控制模型(Cooperative Adaptive Cruise Control, CACC),构建人工驾驶车辆和CAVs的混合交通流偶发拥堵演化模型,探索CAVs混入和诱导干涉措施对混合交通流偶发性拥堵传播规律的影响。实验选取重庆市华陶立交至巴南立交路段为路网原型,对CAVs不同渗透率( Pc )下的路段拥堵演化情况进行仿真。实验结果表明：CAVs渗透率越高,混合流流量、占有率和速度的改善情况越显著,但只有当 Pc ≥ 0.2 时,网联车辆对拥堵消散的改善效果才较为明显;Pc ≤ 0.8 时,干涉措施下,拥堵消散状态的持续时间约为不采用干涉措施的 50%;当 Pc = 1.0 时,网联车辆的通行能力是纯人工驾驶交通流的2.34倍;分别在非干涉措施和干涉措施下计算拥堵评价指标,与仿真结果进行对比,最大相对误差在5.38%之内,验证了模型的准确性。研究成果对疏散交通拥堵具有重要意义。     

嵌入式计算机系统在水下航行器的应用

针对小型水下航行器航行和工作特点,论述了采用嵌入式ＭＣＵ与ＥＤＳＰ器件和Ｉ＾２Ｃ总线技术构成的监测与控制系统。     

城市快速公交专用道道路线形设计分析

以汽车的动力特性和通过特性为理论依据,根据目前快速公交专用车辆大都采用低地板大型铰接底地板车辆的现状,结合其容量比一般普通公交大得多的特点,对快速公交专用道的道路线形设计进行分析,提出设计方法。     

Design of safety-oriented control allocation strategies for overactuated electric vehicles

The new vehicle platforms for electric vehicles (EVs) that are becoming available are characterised by actuator redundancy, which makes it possible to jointly optimise different aspects of the vehicle motion. To do this, high-level control objectives are first specified and solved with appropriate control strategies. Then, the resulting virtual control action must be translated into actual actuator commands by a control allocation layer that takes care of computing the forces to be applied at the wheels. This step, in general, is quite demanding as far as computational complexity is considered. In this work, a safety-oriented approach to this problem is proposed. Specifically, a four-wheel steer EV with four in-wheel motors is considered, and the high-level motion controller is designed within a sliding mode framework with conditional integrators. For distributing the forces among the tyres, two control allocation approaches are investigated. The first, based on the extension of the cascading generalised inverse method, is computationally efficient but shows some limitations in dealing with unfeasible force values. To solve the problem, a second allocation algorithm is proposed, which relies on the linearisation of the tyre–road friction constraints. Extensive tests, carried out in the CarSim simulation environment, demonstrate the effectiveness of the proposed approach.     

Fault classification method for the driving safety of electrified vehicles

A fault classification method is proposed which has been applied to an electric vehicle. Potential faults in the different subsystems that can affect the vehicle directional stability were collected in a failure mode and effect analysis. Similar driveline faults were grouped together if they resembled each other with respect to their influence on the vehicle dynamic behaviour. The faults were physically modelled in a simulation environment before they were induced in a detailed vehicle model under normal driving conditions. A special focus was placed on faults in the driveline of electric vehicles employing in-wheel motors of the permanent magnet type. Several failures caused by mechanical and other faults were analysed as well. The fault classification method consists of a controllability ranking developed according to the functional safety standard ISO 26262. The controllability of a fault was determined with three parameters covering the influence of the longitudinal, lateral and yaw motion of the vehicle. The simulation results were analysed and the faults were classified according to their controllability using the proposed method. It was shown that the controllability decreased specifically with increasing lateral acceleration and increasing speed. The results for the electric driveline faults show that this trend cannot be generalised for all the faults, as the controllability deteriorated for some faults during manoeuvres with low lateral acceleration and low speed. The proposed method is generic and can be applied to various other types of road vehicles and faults.     

The impact of a congestion pricing exemption on the demand for new energy efficient vehicles in Stockholm

As governments seek to transition to more efficient vehicle fleets, one strategy has been to incentivize ‘green’ vehicle choice by exempting some of these vehicles from road user charges. As an example, to stimulate sales of energy efficient vehicles (EEVs) in Sweden, some of these automobiles were exempted from Stockholm’s congestion tax. In this paper the effect this policy had on the demand for new, privately-owned, exempt EEVs is assessed by first estimating a model of vehicle choice and then by applying this model to simulate vehicle alternative market shares under different policy scenarios. The database used to calibrate the model includes owner-specific demographics merged with vehicle registry data for all new private vehicles registered in Stockholm County during 2008. Characteristics of individuals with a higher propensity to purchase an exempt EEV were identified. The most significant factors included intra-cordon residency (positive), distance from home to the CBD (negative), and commuting across the cordon (positive). By calculating vehicle shares from the vehicle choice model and then comparing these estimates to a simulated scenario where the congestion tax exemption was inactive, the exemption was estimated to have substantially increased the share of newly purchased, private, exempt EEVs in Stockholm by 1.8% (±0.3%; 95% C.I.) to a total share of 18.8%. This amounts to an estimated 10.7% increase in private, exempt EEV purchases during 2008, i.e., 519 privately owned, exempt EEVs.