ObjectiveThe metro train air supply system provides power for onboard pneumatic equipment. Insufficient airtightness may lead to a reduction in the efficiency of the air supply system, thereby decreasing the reliability of critical onboard equipment such as braking devices, door control systems, and suspension systems. Therefore, it is necessary to study the airtightness condition of the metro train air supply system. MethodSmall-orifice leakage models as well as flat-plate or annular gap leakage models are analyzed, the effects of leakage location and leakage opening numbers on leakage speed are summarized. Based on the airtightness requirements of air supply system components, a component model with leakage characteristics is developed. Combining the impact of different leakage parameters on leakage speed, a simulation model of the metro train air supply system is developed. A 24-hour static airtightness simulation analysis is conducted for two typical leakage conditions, and the accuracy of the model is verified. Result & Conclusion In the gap leakage model that is closer to the actual leakage characteristics, the total air reservoir pressure can still be maintained at approximately 200 kPa after 24 h of leakage, whereas in the small-orifice leakage model, the pressure approaches zero after 20 h, confirming that the gap leakage is the dominant leakage mode in the system. Leakage location and leakage opening numbers have a relatively small effect on the total leakage speed; at the same pressure level, multiple leakage points can be equivalently represented as a single leakage point. By calibrating the model leakage parameters using measured pressure data, the model can be adapted to different vehicle types, enabling accurate prediction of the airtightness condition and long-term performance evaluation of the air supply system.

[Objective] Extreme passenger flow conditions characterized by sudden changes in passenger load may occur at interchange stations for urban rail transit trains. During such conditions, if the air supply system fails to provide sufficient air within the station dwell time, the air spring suspension system may be unable to lift the carbody off the emergency rubber stacks upon train start-up. This can adversely affect ride comfort and braking safety. Therefore, it is necessary to study the air supply system performance in urban rail transit trains under extreme passenger boarding/alighting conditions. [Method] A model of the train air supply system and air spring suspension system is established. The performance of the air supply system under different air reservoir configurations is simulated for the extreme boarding condition of completing AW0 (empty load) to AW3 (overload) process within station dwell time, and for the extreme interchange condition of AW3-AW0-AW3 process. [Result & Conclusion] Configuring air spring reservoirs has significant effect on the air spring suspension system, enabling it rapidly restore air spring pressure to the specified level during load changes under extreme mass passenger flow boarding/alighting conditions. The volume of the air reservoir should be determined based on multiple factors, including the volume of the air springs and additional reservoirs, station dwell time, actual passenger volume, and available installation space on the vehicle. This method can be used for parameter optimization of train air supply systems to ensure performance requirements are met under extreme operating conditions.

To address the need for automated uncoupling prior to car dumper operations in coal transportation systems, this paper designed a novel dual-arm automatic uncoupling robot system, which includes a synchronization-arm and an uncoupling-arm. The system comprises a mechanical structure, a control system, and a vision module. Kinematic and dynamic models were derived, and its dynamic simulation model was established. By using gravity-compensated PD control strategy, the joint angle errors were controlled within 0.3°. A dual-arm uncoupling robot test platform was built in the laboratory. The test results showed that the designed robot system could stably and reliably complete the detection, recognition, and uncoupling operation with a load of 50 kg when the coal wagon is running at a speed of 1.5 m/s, and the entire uncoupling process takes about 6 seconds.

[Objective]Metro trains experience wheel wear and noise issues when negotiating small radius curve section.Active radial technology for bogie wheelsets is considered an effective solution theoretically.It is essential to conduct in-depth research on this technology.[Method]The control ob-jective of'radial steering'is determined by analyzing the prin-ciple of active radial technology.A controllable rubber joint device and its control system for the swing-arm axle box posi-tioning bogie are proposed,transforming it into an active radial device for the vehicle.The active radial guidance principle of the device is elucidated,involving the metro train obtaining track information in a beacon-like manner,storing information of each curve in the radial controller,determining the train po-sition along curve based on train operating speed.This controls the action of the controllable rubber joint device,further enab-ling the wheelset to negotiate curves in a radial attitude.Taking the leading car of the train as the research object,an A-type metro train dynamic model is established.The passing per-formance of a metro train equipped with the active radial device is analyzed at a speed of 60 km/h through a curve radius of 400 m,and the negotiation performance is compared with the conventional bogie for reference.[Result & Conclusion]Compared to conventional bogie-guided wheelsets,the active radial bogie-guided wheelsets exhibit significantly reduced flange angle and wear index.Both wheelsets on the same bogie have similar lateral displacement,allowing the wheelsets to a-chieve'pure rolling'at this position.The performance of train negotiating small radius curves is noticeably improved.

地铁列车制动系统是关系列车安全的重要单元.列车制动系统不仅受制动控制装置、制动执行机构性能的影响,制动控制装置与基础制动装置间的管路对系统性能同样具有重要影响.制动管路由于受到车体下方车载设备布置位置的影响不可避免存在弯折.基于地铁车辆制动管路布置的特点,对管路接头、管径、长度等参数的影响展开分析,以获取较为优化的管路参数.仿真基于AMESim环境进行.仿真结果表明制动管路参数对地铁列车制动性能有重要影响.筛选最优制动管路内径尺寸范围为11～13 mm,在此范围内进一步选型实现制动管减重 24.2%和制动空气消耗量减少 4.9%.研究工作除保证满足制动系统性能外,还有利于减轻系统重量、减小空气消耗量,充分体现轨道交通绿色环保的特点.

Structural health monitoring (SHM) is widely applied to assess the service condition of bridges. Deflection measurements are essential to determine a bridge's performance, and in particular, dynamic deflection is increasingly required in SHM. However, continuous and high-precision measurements of the absolute dynamic deflection are challenging without a reference point placed at a distance from the bridge. We proposed a reference point-free dynamic deflection measurement system consisting of a level sensor and an accelerometer. The level sensor measures the low-frequency deflection components, while the accelerometer measures the high-frequency deflection components. We redesigned the level sensor from the hydrostatic level sensor and further provided a correction method to achieve the dynamic deflection measurement. A numerical algorithm fuses the signals from the level sensor and accelerometer to obtain the absolute dynamic deflection, and key parameters are calculated. The accuracy of the measurement system was tested in the laboratory, and the sensor results were similar to the ones obtained by the laser test under simple harmonic and random excitations. Field tests conducted on a T-shaped rigid frame bridge with random traffic flow indicate that the system can achieve continuous high-precision deflection measurements of bridges loaded by traffic flow.

目前列车纵向动力学仿真的积分算法多以 Newmark-β法为基础的固定步长算法为主,但随着列车编组数量增加以及工况变化,固定步长算法难以获得最佳的计算效率.基于此,文章采用显式预测-隐式迭代校正的方法,在Newmark-β法的基础上,通过限制迭代次数的方法变化步长,将其演变为一种变步长的积分算法.通过算例验证了变步长算法在动力学方程解变化剧烈的时候具有更高的计算精度,将该算法应用至 1 万t单编列车的全制动停车工况的纵向动力学仿真,结果表明,相较于其他算法,变步长的积分算法在保证精度的同时计算效率更高.

地铁列车制动系统是列车重要用风单元.过去多采用模拟式制动系统,利用中继阀控制制动缸的压力.随着数字式高速开关阀的控制技术的运用,地铁列车制动系统目前普遍使用了数字式制动系统取代模拟式制动系统,利用EP阀控制制动缸压力.此种对压力的控制方法与模拟式制动系统不同.传统的制动系统用风量计算方法仅考虑制动缸和管路耗气,本文提出一种新的用风量计算方法,通过搭建地铁列车制动系统AMESim模型对地铁列车制动系统各用风元件进行用风量计算,可获得制动系统工作中所有元件的总用风量.

With the continuous expansion of railroad operation mileage, the detection of rail surface defects has become of utmost importance for ensuring the safe operation of trains. Rail surface defects contain various types such as abrasion, spalling, and corrugation, which exhibit significant scale variations and distinct shapes. Consequently, detecting these defects brings considerable challenges. In this paper, we proposed a Mask R-Transformer rail surface defect detection and identification method with Swin Transformer as the backbone network to address the characteristics of rail surface defects. We constructed a rail surface defect dataset containing corrugation and spalling by manually annotating the defects in actual rail images and model training was conducted on both the public dataset and our self-built dataset, respectively. Experimental results demonstrate that the proposed method achieves an impressive mean Average Precision (mAP) of 94.4% for rail surface defect detection and recognition, outperforming the Mask R-CNN algorithm employing Resnet101 as the backbone network by 3.7%.

针对列车制动系统传统整体仿真模型,随着编组的加长,模型状态数增加,仿真速度变慢的问题,以动力集中动车组制动系统为例,依据AMESim软件提供的并行及分区仿真方法,在建立机车、客车车辆制动系统模型基础上,利用AMESim软件自带的联合仿真元件,构建列车制动系统分布式仿真模型.通过在列车编组定置试验台上进行试验,对比实际试验与仿真分析结果,验证了分布式仿真方法的有效性.在获得相同仿真准确性的条件下,可比传统方法大大减少仿真时间.该分布式仿真方法为提高具有大状态数模型的长大列车制动系统的仿真速度提供了一种新的思路.

列车在长大下坡道运行时的制动操纵方法直接关系到车辆车轮或制动盘热负荷大小,影响列车安全运行.为确定快速货运列车在川藏线路某长大下坡道路段的最优制动操纵方法,通过建立轴装制动盘三维有限元模型,计算三种制动操纵方法下的制动盘热流密度和对流换热系数,建立瞬态温度场,完成对制动盘的热负荷分析.结果表明,短循环制动法满足制动盘温度性能要求,但对司机操纵要求较高,易发生疲劳驾驶;一次减压制动法对司机操纵要求低,但超出制动盘最高温度允许范围;长循环制动法结合以上两种,既减轻了司机操纵压力,又满足了制动盘温度性能要求,可作为川藏线长大下坡道的最优安全下坡操纵方法.

针对目前轮轨接触斑及接触应力分布难以有效检测的问题,基于接触面的准静态弹簧模型与超声波反射法,设计一种适用于静态轮轨接触状态检测的系统.系统采用水浸式点聚焦超声探头进行检测,主要由机械结构部分、超声波激励采集系统和接触斑及应力分析显示系统组成.机械结构部分包括轮轨加载机构和两轴扫描机构,分别实现对轮轨的固定与加载,以及夹持超声探头进行平面扫描运动;超声波激励采集系统实现对扫描机构的运动控制以及超声波信号的激励、采集和传输,并与接触斑及应力分析显示系统通过以太网通信,实现命令接收与超声波数据的上传;接触斑及应力分析显示系统实现超声数据的接收与处理,并实时显示和存储检测结果.利用所搭建的检测系统首先进行标定实验,建立超声声压反射系数与接触应力之间的关系,然后进行轮轨接触斑与应力分布检测实验,获得了20～70 kN载荷下车轮试件与钢轨的接触斑及应力分布云图,最后采用3次样条插值处理优化了检测效果.实验结果表明:所提出的检测方法与系统能够有效检测静态轮轨接触斑几何形状与接触应力的分布情况,反映真实的轮轨接触状态.对于轮轨的优化设计、寿命预测和轨道维护等研究都具有重要作用和意义.

为了有效验证列车编组中所采用的吸能结构配置方式及性能,文章基于多体系统动力学和Matlab GUI平台建立了钩缓装置和防爬器模型,开发了列车纵向冲击性能分析软件包.通过对比分析相同计算参数下软件包与Simpack软件的计算结果,证明了该软件包计算的有效性.

转向架轮对主动导向技术可以很好地解决传统转向架设计过程中运行稳定性和曲线通过性相互矛盾的问题.针对目前几种主动导向装置的特点,在此基础上提出一种用于转臂式轴箱定位转向架的主动导向装置.该主动导向装置将2个柱塞缸集成于橡胶节点内.当车辆通过曲线时,通过控制其中一侧的柱塞,使其推动轴箱相对于构架沿纵向方向运动,实现对轮对的主动导向,并对该装置的性能进行了分析,该主动导向装置性能优良.研究结果可为轮对主动导向技术的工程化应用提供技术思路.

川藏铁路线路起伏较大、长大下坡较多,对开行列车进行纵向动力学性能评估十分必要.本文建立了包括机车DK-2制动机和货车120阀在内的列车制动系统AMEsim模型,并结合Simulink建立的纵向动力学仿真模型,进行列车纵向动力学仿真,评估川藏线即将开行货运列车的纵向动力学性能,完成了下坡道紧急制动和循环制动工况的仿真分析.结果表明,机车的制动是造成纵向冲动的主要因素;由于编组较短,空气制动不同步性对列车纵向冲动影响较小;最大车钩力和加速度发生在制动刚开始时,整个制动过程列车总体运行平稳.

采用模糊综合评价方法对铁道客车的技术代系进行了研究.在模糊综合评价方法的基础上,将构成客车的车体、转向架、车钩缓冲装置、制动系统及车载电器设备的关键技术作为评价指标,建立了铁道客车分层次模糊评价模型.通过对各技术指标发展及技术性能指标的模糊化处理,构建了模糊评价矩阵,得到了各型车辆的技术评价值.按照各型车辆的技术评价值分布来判定车辆所属的技术代系,分析结果反映出了我国铁道客车的技术发展历程,可为新一代车辆的研发提供一种技术评价方法.

电磁超声换能器能进行非接触检测,使用方便,但缺点是换能效率低,为了提高横波电磁超声换能器的换能效率,分析电磁超声换能器工作原理,利用COMSOL Multiphysics软件对电磁超声换能器进行三维建模仿真,分析了永磁体不同放置方式和几何尺寸对换能器激励洛伦兹力大小的影响.进一步应用正交试验法对蝶形线圈的几何尺寸参数进行优化设计,得到最佳的横波换能效率.最后,利用超声波检测系统进行铝板测厚试验.结果表明,永磁铁垂直放置激发横波的效率更高,采用蝶形线圈激励超声横波信号的幅值比螺旋线圈高出50％,蝶形线圈比螺旋线圈具有更理想的横波换能效率.

连通管液位测量是实现桥梁挠度检测的一种重要方式.针对传统连通管液位测量方法存在的实时性和测量精度不足的问题,基于机器视觉研究了一由液位观测管、光源、平行光板、工业相机、微型处理器和路由器等构成的连通管液位测量系统.通过图像预处理获取液位图像边缘轮廓,并采用亚像素边缘检测算法进一步精确定位液位图像边缘轮廓的底部坐标.提出了一种基于相对运动原理的液位高度标定测量方法,利用最小二乘法拟合得到液位图像边缘轮廓底部坐标与液位高度的函数关系.最后在实验室通过静态测量试验与拟桥振动试验验证了该液位测量方法的可行性、准确性和动态响应性,其最大绝对测量误差不超过0.5 mm,能够满足连通管桥梁挠度测量的工程应用需要.

针对SYS510e型空气弹簧底板的金属橡胶粘接结构橡胶脱粘缺陷超声检测难以辨识问题,提出采用改进的线性调频脉冲代替传统窄脉冲作为超声波激励信号,增大超声检测的信号能量和频谱宽度.在宽频带超声检测的基础上,采用小波包-奇异值分解方法解析超声回波在不同粘接状态、不同频率范围的时频能量分布,提取更稳定、一致性更好的橡胶脱粘辨识特征值.根据特征训练BP神经网络对空气弹簧的橡胶脱粘缺陷进行超声C扫描检测.结果显示,基于改进的线性调频脉冲激励的超声检测方法能够准确有效地辨识橡胶脱粘缺陷的位置和轮廓,满足对SYS510e型空气弹簧的超声脱粘检测需求.

针对当前传统铆钉拆除设备工作时伤害母材、切除效率低下等问题,利用电火花加工技术设计一款便携式电火花铆钉切除设备.为了提高铆钉电火花切除设备的实用性,提高铆钉切除效率和降低电极损耗是其关键.在介绍所研制的便携式电火花铆钉切除设备的结构和工作原理的基础上,采用正交试验法对四个主要加工工艺参数进行双目标优化,选择工作脉冲频率、脉冲占空比、工作电压和工具电极进给速度四个参数作为试验因素,加工效率和电极损耗率作为试验指标.通过对LMB10型号的拉铆钉进行正交试验,采用极差分析法确定了各影响因素对目标指标的影响次序以及各因素的最佳水平,得出了切除该型号铆钉的加工工艺参数的最佳组合.