Automated cars: Queue discharge at signalized intersections with ‘Assured-Clear-Distance-Ahead’ driving strategies

This study addresses the impacts of automated cars on traffic flow at signalized intersections. We develop and subsequently employ a deterministic simulation model of the kinematics of automated cars at a signalized intersection approach, when proceeding forward from a stationary queue at the beginning of a signal phase. In the discrete-time simulation, each vehicle pursues an operational strategy that is consistent with the ‘Assured Clear Distance Ahead’ criterion: each vehicle limits its speed and spacing from the vehicle ahead of it by its objective of not striking it, regardless of whether or not the future behavior of the vehicle ahead is cooperative. The simulation incorporates a set of assumptions regarding the values of operational parameters that will govern automated cars’ kinematics in the immediate future, which are sourced from the relevant literature.We report several findings of note. First, under a set of assumed ‘central’ (i.e. most plausible) parameter values, the time requirement to process a standing queue of ten vehicles is decreased by 25% relative to human driven vehicles. Second, it was found that the standard queue discharge model for human–driven cars does not directly transfer to queue discharge of automated vehicles. Third, a wet roadway surface may result in an increase in capacity at signalized intersections. Fourth, a specific form of vehicle-to-vehicle (V2V) communications that allows all automated vehicles in the stationary queue to begin moving simultaneously at the beginning of a signal phase provides relatively minor increases in capacity in this analysis. Fifth, in recognition of uncertainty regarding the value of each operational parameter, we identify (via scenario analysis, calculation of arc elasticities, and Monte-Carlo methods) the relative sensitivity of overall traffic flow efficiency to the value of each operational parameter.This study comprises an incremental step towards the broader objective of adapting standard techniques for analyzing traffic operations to account for the capabilities of automated vehicles.     

相干信号源的空间平滑法处理及其效果分析

介绍了相干信号DOA空间平滑技术处理的方法及其效果分析，并给出了处理非相干和相干信号源的仿真结果，实验结果证明了空间平滑技术能够去相干性，达到了对相干信号源的方向进行识别的目的。     

基于模糊模式诊断柴油机燃油系统故障

利用夹持式传感器检测高压油管外壁弹性变形,通过对高压油管油压波形进行分析比较,提取反映故障状态的特征向量,利用模糊模式识别技术诊断燃油系统的典型故障。     

新型机车信号检测环线安装方法探究

针对目前传统的机车信号测试环线安装在钢轨内侧腰部存在一定的磁屏蔽、安装相对不是很容易、施工钢轨穿孔困难等缺点,结合具体施工等实际因素,设计并实现了一种成本较为低廉、安装方便、削弱构成磁屏蔽的一种机车信号测试环线支架法。该方法采用自主设计,特定加工的环线支架固定在钢轨上,环线通过支架安装在钢轨外侧,高度基本与钢轨高度水平。实践证明,这种环线支架法较之前传统的安装方式使用效果良好、信号检测稳定,设计经过实践检验基本合理,能满足机车信号的正常检测,在一定程度上优化了设计,方便了施工,达到了预期目标。     

基于PCA和随机Hough变换的调车信号灯检测

针对传统信号灯检测方法中存在的弊端,提出了一种主成分分析(Principal Component Analysis,PCA)和圆拟合与分段随机Hough变换(Randomized Hough Transform,RHT)圆检测相结合的信号灯检测方法。该方法利用主成分分析结合圆拟合来简化图像的复杂背景,然后通过随机Hough变换进行分段圆检测,得到信号灯的准确位置,最后结合线路特征及信号灯的颜色特点,确定本股道有显示的调车信号灯。对调车信号灯图像进行仿真实验,结果表明,该方法检测准确度高,实时性好,并对有颜色信号灯的检测具有良好的检测效果,适合于对复杂环境中调车信号灯的准确检测和定位。     

多功能信号源的设计

产品级信号发生器往往满足不了科研和实验的需要。为了得到一系列所需的信号，采用CPLO／FPGA在QuartusⅡ开发软件和ALTERA公司的MAX7000S系列EPM7192SQX160-10实现了简易信号发生器的设计。     

电源零地电压对地铁通信信号系统的影响分析

通过分析地铁通信信号供电系统零地电压的形成机理,论述零地电压产生的不可避免性和对通信信号设备负载可能的影响,建议通信信号系统的使用、设计和工程人员应该正确地看待零地电压问题,走出零地电压的技术误区,避免不必要的资源浪费.     

铁路无线便携智能机车信号测试仪系统

铁路无线便携智能机车信号测试仪系统,采用WiFi无线网络控制技术,实现机车信号车载系统设备功能指标检测和地面环线发码检测,利用USB接口进行记录信息转储、测试报表生成,利用RFID卡技术实现设备管理,方便铁路一线技术维护人员的测试和设备管理。     

站内咽喉区道口与计算机联锁结合研究及应用

结合工程实例,对站内咽喉区道口接近通知时间、接近通知点及道口信号机位置等方面进行分析研究,提出咽喉区道口信号与车站计算机联锁系统结合方案、接口技术条件及电路,通过计算机联锁逻辑驱动道口接近和到达条件,实现道口自动通知及道口自动信号,保证站内咽喉区道口行车安全。