Safe Platooning in Automated Highway Systems Part I: Safety Regions Design

This paper addresses the problem of designing safe controllers for vehicle manuevering in Automated Highway Systems (AHS) in which traffic is organized into platoons of closely spaced vehicles. Conditions to achieve safe platooning under normal modes of operation are investigated. The notion of safety is related with the absence of collisions that exceed a given relative velocity threshold. State dependent safety regions for the platoons are designed in such a way that, whenever the state of a platoon is inside these safety regions, it is guaranteed that platoon maneuvering will be safe and follow the behavior prescribed by the finite state machines that control vehicles manuevers. It is shown that it is possible to design control laws that keep the state of the platoons inside these safety regions. The results obtained allow one to decouple the controllers for the regulation of the manuevers and the finite state machines that determine their proper sequence in AHS architectures. The overall complexity of the design and verification of the AHS as an hybrid system is therefore greatly reduced.     

Safe Platooning in Automated Highway Systems Part I: Safety Regions Design

This paper addresses the problem of designing safe controllers for vehicle manuevering in Automated Highway Systems (AHS) in which traffic is organized into platoons of closely spaced vehicles. Conditions to achieve safe platooning under normal modes of operation are investigated. The notion of safety is related with the absence of collisions that exceed a given relative velocity threshold. State dependent safety regions for the platoons are designed in such a way that, whenever the state of a platoon is inside these safety regions, it is guaranteed that platoon maneuvering will be safe and follow the behavior prescribed by the finite state machines that control vehicles manuevers. It is shown that it is possible to design control laws that keep the state of the platoons inside these safety regions. The results obtained allow one to decouple the controllers for the regulation of the manuevers and the finite state machines that determine their proper sequence in AHS architectures. The overall complexity of the design and verification of the AHS as an hybrid system is therefore greatly reduced.     

Lane assignment problem using a genetic algorithm in the Automated Highway Systems

This paper deals with the lane assignment problem in the Automated Highway Systems (AHS). The purpose of lane assignment strategies is to increase throughput on multi-lane highways with many entry and exit points, based on the itineraries of vehicles using the highway (point of entry, time of entry and exit point) and the effects of maneuvers. Using partitioned lane assignment strategies, the lane assignment problem is formulated as an optimization problem to find the proper positions of partitions. Then the optimal problem is solved using a Genetic Algorithm (GA). The proposed algorithm has been validated by comparing its solution with that of an all-cases algorithm for a simple case. Moreover, a traffic simulator with a realistic car-following model as well as lane change logic has been developed. The simulation results show the efficiency of the proposed genetic algorithm, compared with random assignment algorithms.     

公路改建项目安全选线理念的实际应用

结合工程实例,介绍了安全选线理念在公路改建项目中的实践经验,对于类似地形条件下的国省道改建工程提供参考。     

Autonomous Lateral Control of Vehicles in an Automated Highway System

Lateral control of vehicles in IVHS requires the installation of on-board sensors as well as the installation of roadway hardware such as cables, magnets, etc. Existing control approaches in PATH require road curvature and vehicle lateral position (with respect to the center of the lane) information. Hence these approaches rely on roadway sensors to obtain relative lateral position. These methods will necessitate infrastructural changes to the highway.

This paper introduces the concept of autonomous lateral control or auto-tracking. The method allows us to use only line-of-sight sensor information to effect vehicle control. We present a detailed vehicle model. Controllers have been proposed to demonstrate the effectiveness of the proposed auto-tracking scheme. We also examine the possibilities of using this method for lane change purposes in an automated highway system.     

Autonomous Lateral Control of Vehicles in an Automated Highway System

SUMMARY

Lateral control of vehicles in IVHS requires the installation of on-board sensors as well as the installation of roadway hardware such as cables, magnets, etc. Existing control approaches in PATH require road curvature and vehicle lateral position (with respect to the center of the lane) information. Hence these approaches rely on roadway sensors to obtain relative lateral position. These methods will necessitate infrastructural changes to the highway.

This paper introduces the concept of autonomous lateral control or auto-tracking. The method allows us to use only line-of-sight sensor information to effect vehicle control. We present a detailed vehicle model. Controllers have been proposed to demonstrate the effectiveness of the proposed auto-tracking scheme. We also examine the possibilities of using this method for lane change purposes in an automated highway system.     

高海拔公路隧道火灾烟气控制临界风速研究

为了探究高海拔与低海拔公路隧道火灾燃烧特性的差异,掌握高海拔隧道火灾烟气控制临界风速计算方法,给高海拔隧道防灾通风及人员疏散设计提供参考,建立1∶16的缩尺寸移动式水平模型隧道试验台,对海拔高度为504、3 297、3 544、4 103、4 446 m的5个地点开展隧道火灾热释放率试验研究,并采用三维数值计算方法和量纲分析,对不同海拔高度、不同火灾热释放率工况下水平隧道内烟气控制临界风速进行研究和分析。结果表明：在油盘尺寸相同的情况下,随着海拔高度的增加,火灾热释放率明显减小,燃烧时间显著增长,当海拔超过3 000 m时,高海拔地区隧道稳定段火灾热释放率仅为海拔504 m隧道火灾稳定段热释放率的60.9%。隧道火灾临界风速随着海拔高度的增加而增大,其表现出2种典型变化规律：火灾热释放率大于30 MW时,海拔高度对临界风速影响较小,同一火灾热释放率下,海拔5 000 m时隧道内临界风速较海拔0 m时提高了不到2%;火灾热释放率小于30 MW时,海拔高度对临界风速的影响显著增强,且随着热释放率的减小影响不断增大,当火灾热释放率分别为5.73、12.67 MW时,海拔5 000 m隧道内临界风速较海拔0 m时分别提高了26%和13%。基于高海拔隧道火灾热释放率及隧道火灾临界风速的变化规律,提出了典型双车道高海拔隧道火灾烟气控制临界风速的计算方法。     

公路平面测量坐标系的选择方法

分析了影响平面测量坐标系选择的所有要素,介绍了目前世界上常用的地图投影方式,结合公路的特点,建议公路平面测量坐标系的选择应根据测量区域地理位置、海拔高度以及公路工程的要求,选择合适的参考椭球、抵偿高程面和投影方式。     

基于安全车速差的高速公路特长隧道环境驾驶人行为风险特性研究

为研究高速公路特长隧道环境下驾驶人行为风险特性,选取2座典型特长隧道进行实车试验,通过采集熟练驾驶人和非熟练驾驶人的速度数据,将此作为主观预期车速,结合道路行车环境的客观安全车速,构建基于安全车速差的驾驶人行为风险量化方法。在划分隧道路段为入口段、行车段和出口段的基础上,通过切分行车区间,对比分析出入口段2类驾驶人行为风险变化特性及整个隧道路段和普通高速路段的行为风险变化曲线。结果表明： 1)在隧道内部,相对于非熟练驾驶人,熟练驾驶人表现出更高的行为风险值;在隧道外部,则非熟练驾驶人的行为风险值更高一些。2)所有类型驾驶人在普通高速路段行为风险值最高,在隧道入口段的行为风险值最低。上述结果说明： 在隧道路段,熟悉试验道路的驾驶人车速行为并不安全,行为风险值相对较高。     

Improvements in Dynamic Characteristics of Automobile Suspension Systems Part 1. Two-Mass Systems

In a previous paper, [3] the random vibrations of simple linear models of automobile suspension were solved with respect to seat elasticity and human sensitivity to vibrations. The present study uses more realistic linear models taking into account the unsprung mass.

Two configurations of masses are investigated: a two-mass system consisting of a sprung mass and an unsprung mass, and a three-mass system having an additional mass which acts as a vibration absorber. The gain in comfort obtained by lowering the natural frequency of the sprung mass is calculated for various two-mass and three-mass models along with other characteristics such as the dynamic tyre load, spring and damper forces and relative motion of the masses.     

Effects of Model Complexity on the Performance of Automated Vehicle Steering Controllers: Controller Development and Evaluation

SUMMARY

Due to increased traffic congestion and travel times, research in Advanced Vehicle Control Systems (AVCS) has focused on automated lateral and headway control. Automated vehicles are seen as a way to increase freeway capacity and vehicle speeds while reducing accidents due to human error. Recent research in automated lateral control has focused on vehicle control during low-g maneuvers. To increase safety, automated lateral controllers will need to recognize and react to emergency situations.

This paper investigates the effects of vehicle and tire model order on the response of automated vehicles to an emergency step lane change using a controller based on linear vehicle and tire models. From these studies it is concluded that control strategies based solely on linear vehicle and tire models are inadequate for emergency vehicle maneuvers.

A strategy is then proposed to automatically control vehicles through emergency maneuvers. Here the response of a nonlinear vehicle model is used with a linear state model to optimize controller gains for nonlinear maneuvers. An emergency step lane change is used as a preliminary test of the method.     

Web环境下公路工程造价审查系统研究

针对目前公路工程造价审查体系存在的问题，在分析群体决策支持系统、多Agent和数据库技术发展趋势的基础上，对Web环境下的公路工程造价审查系统的体系框架进行了优化设计。并提出了造价资料的分步综合审查法。     

在京珠国道主干线湖北北段暨武汉军山长江公路大桥通车仪式上的讲话（节选）

(2001年12月15日) 湖北京珠高速公路是北京-珠海高速公路的重要组成部分,是国家"九五"和"十五"交通重点建设工程之一,主线建设总里程339 km,概算投资122.6亿元人民币.该工程由京珠湖北北段、武汉军山长江公路大桥、京珠湖北南段3个项目组成,由北向南纵贯孝感、武汉、咸宁3个市的10个县(区),它是我省第一次利用世界银行贷款的交通建设项目,第一次全线采用沥青砼路面,第一次进行完善的路基路面排水系统和超限运输系统设计,第一次对环境保护以及全线景观进行专项设计,第一个将高速公路土建工程与服务设施、机电工程同时设计、同时建设并同步完成的高速公路项目.     

PID Controller Modelling and Optimization in Cr Systems with Standard and Reduced Accumulators

The proportional-integrative-derivative (PID) controller and the pressure control valve of a Common Rail system are modelled by taking into account electronic, electrical, hydraulic and mechanical aspects. A fully predictive model of the injection apparatus is realized and validated by means of comparison with experimental data. The effects of the PID parameters on the injection system dynamics are illustrated and discussed on the basis of model results, which refer to steadystate and transient working conditions. The influence of the accumulator size on the rail pressure time history is investigated when the rail volume is dramatically reduced (up to 2.5 cm³). In particular, the effect of the large rail pressure drop that occurs at the end of the main injection for Minirail layout solutions is examined when after injections are implemented. An objective is to try to determine possible suitable values of the PID controller parameters and of the pressure-sensor sampling-frequency for rails of reduced size.     

部分二次二阶矩法在公路边坡可靠度分析中的应用

为研究边坡结构可靠性,利用随机摄动理论和精度较高的部分二次二阶矩法(PSOSM),考虑边坡结构上主要随机变量(如土性参数粘聚力c、摩擦系数f和重度γ等)对结构可靠性的影响,研究了各随机变量在相互独立和相关的情况下对公路边坡结构可靠性的影响,并计算了结构的可靠指标β和β对这些随机因素的敏感度。结果表明:当随机变量围绕各自均值向正、负方向波动时,边坡可靠指标β对c正负方向变化的敏感性相同,而β对f和γ负方向变化的敏感性更大,说明f和γ围绕各自均值由减小方向变化时,对结构可靠性影响更大。另外,在考虑参数间互相独立和相关两种情况下,同一随机参数对结构可靠指标β具有不同的影响结果。说明参数随机性在公路边坡结构可靠性分析中是不容忽视的。     

21世纪初我国公路隧道的关键技术

经过近２０年的积累，我国公路隧道在质和量上都有显著进步，２１世纪初隧道建设难度方面将面临更加严峻的挑战。为此需要在水下隧道修建技术，公路隧道数据库及信息化设计与施工技术，山岭隧道施工技术、特长隧道营运通风技术、公路隧道节能照明技术、营运监控系统开发、病害诊断与整治技术等方面加大研究力度，从而掌握制约我国公路隧道发展的关键技术。