Wide speed range for traction motor in braking force of electric braking control system

A vehicle stopping method using an electric brake until a traction motor is stopped is studied. At the moment of vehicle stop, electric brake is changed to control mode where torque is reduced at a low speed. Gradient is controlled by estimating the load torque of motor, thereby traction motor is not rotated after stop. In addition, coasting operation and brake test are performed from normal-opposite operation and start using a small-scale model comprising the inertial load equipment and the power converter. Further, traction motor is made to be equipped with a suspension torque. Pure electric braking that makes traction motor stop by an air brake at the time of stop is also implemented. Constant torque range and constant power range are expanded during braking so that braking force is secured with the electric brakes even in high speed region. Therefore, vehicle reduction effect can be expected by reducing parts related with an air brake which is not used frequently by using a pure electric brake in the M car in wide speed region. Further, maintenance of brake system can be reduced. Besides, ride comfort of passenger in the electric rail car, energy efficiency improvement, and noise reduction effect can be additionally expected. Further, an improved brake method that uses only an electric brake till motor stop is proposed by comparing those in the blending brake that uses an air brake while reducing brake torque at vehicle stop.

Numerical Calculation of Dynamic Response for Multi-Span Non-Uniform Beam Subjected to Moving Mass with Friction

In order to simulate the coupling vibration of a vehicle or train moves on a multi-span continuous bridge with non-uniform cross sections, a moving mass model is used according to the Finite Element Method, the effect of the inertial force, Coriolis force and centrifugal force are considered by means of the additive matrices. For a non-uniform rectangular section beam with both linear and parabolic variable heights in a plane, the stiffness and mass matrices of the beam elements are presented. For a non-uniform box girder, Romberg numerical integral scheme is adopted, each coefficient of the stiffness matrix is obtained by means of a normal numerical computation. By applying these elements to calculate the non-uniform beam, the computational accuracy and efficiency are improved. The finite element method program is worked out and an entire dynamic response process of the beam with non-uniform cross sections subjected to a moving mass is simulated numerically, the results are compared to those previously published for some simple examples. For some complex multi-span bridges subjected to some moving vehicles with changeable velocity and friction, the computational results, which can be regarded as a reference for engineering design and scientific research, are also given simultaneously.

Dynamic analysis of traction motor in a locomotive considering surface waviness on races of a motor bearing

The traction motor is the power source of the locomotive.If the surface waviness occurs on the races of the motor bearing,it will cause abnormal vibration and noise,accelerate fatigue and wear,and seriously affect the stability and safety of the traction power transmission.In this paper,an excitation model coupling the time-varying displacement and contact stiffness excitations is adopted to investigate the effect of the surface waviness of the motor bearing on the traction motor under the excitation from the locomotive-track coupled system.The detailed mechanical power transmission path and the internal/external excitations(e.g.,wheel–rail interaction,gear mesh,and internal interactions of the rolling bearing)of the locomotive are comprehensively considered to provide accurate dynamic loads for the traction motor.Effects of the wavenumber and amplitude of the surface waviness on the traction motor and its neighbor components of the locomotive are investigated.The results indicate that controlling the amplitude of the waviness and avoiding the wavenumber being an integer multiple of the number of the rollers are helpful for reducing the abnormal vibration and noise of the traction motor.

Assessment of the curving performance of heavy haul trains under braking conditions

To study the curving performance of trains, 1D and 3D dynamic models of trains were built using nu- merical methods. The 1D model was composed of 210 simple wagons, each allowed only longitudinal motion; whereas the 3D model included three complicated wagons for which longitudinal, lateral, and vertical degrees of freedom were considered. Combined with the calculated results from the 1D model under braking conditions, the behavior of draft gears and brake shoes were added to the 3D model. The assessment of the curving performance of trains was focused on making comparisons between idling and braking conditions. The results indicated the following： when a train brakes on a curved track, the wheel-rail lateral force and derailment factor are greater than under idling conditions. Because the yawing movement of the wheelset is limited by brake shoes, the zone of wheel contact along the wheel tread is wider than under idling conditions. Furthermore, as the curvature becomes tighter, the traction ratio shows a nonlinear increasing trend, whether under idling or braking conditions. By increasing the brake shoe pressure, train steering becomes more difficult.

Problems,assumptions and solutions in locomotive design,traction and operational studies

Locomotive design is a highly complex task that requires the use of systems engineering that depends upon knowledge from a range of disciplines and is strongly oriented on how to design and manage complex systems that operate under a wide range of different train operational conditions on various types of tracks.Considering that field investigation programs for locomotive operational scenarios involve high costs and cause disruption of train operations on real railway networks and given recent developments in the rollingstock compliance standards in Australia and overseas that allow the assessment of some aspects of rail vehicle behaviour through computer simulations,a great number of multidisciplinary research studies have been performed and these can contribute to further improvement of a locomotive design technique by increasing the amount of computer-based studies.This paper was focused on the presentation of the all-important key components required for locomotive studies,starting from developing a realistic locomotive design model,its validation and further applications for train studies.The integration of all engineering disciplines is achieved by means of advanced simulation approaches that can incorporate existing AC and DC locomotive designs,hybrid locomotive designs,full locomotive traction system models,rail friction processes,the application of simplified and exact wheel-rail contact theories,wheel-rail wear and rolling contact fatigue,train dynamic behaviour and intrain forces,comprehensive track infrastructure details,and the use of co-simulation and parallel computing.The cosimulation and parallel computing approaches that have been implemented on Central Queensland University’s High-Performance Computing cluster for locomotive studies will be presented.The confidence in these approaches is based on specific validation procedures that include a locomotive model acceptance procedure and field test data.The problems and limitations presented in locomotive traction studies in the way they are conducted at the present time are summarised and discussed.

用于电梯曳引机减振的MR-SRC减振器设计与分析

针对现有曳引机减振常采用的高分子减振垫因环境因素而引发性能大幅退化问题,以电梯曳引机减振器的工程应用需求为导向,确定减振器所需阻尼元件的刚度后,采用真空渗流技术将硅橡胶填充入金属橡胶孔隙并形成包覆,研制出一款耐环境影响的高性能金属橡胶/硅橡胶连续互穿相复合减振材料(metal rubber-silicone rubber continuous interwoven phase composite damping material, MR-SRC)。然后基于实际结构建立电梯曳引机的有限元数值模型。对加装MR-SRC减振器前后的电梯曳引机进行了模态分析,确定了整体结构的固有频率和振型。对MR-SRC减振器进行冲击响应分析,对比不同MR-SRC材料和冲击载荷对响应的影响,校核减振器的强度。接着,基于MR-SRC的近似等效,对减振器系统的冲击响应进行了理论计算,得出金属橡胶密度为1.8 g/cm^(3)的MR-SRC减振器对减振效果最佳。最后将所制备的MR-SRC减振器安装于实际电梯曳引机,按照电梯减振国标要求,测试电梯在运行过程中的加速度和速度变化,计算并校核电梯运行的相关特性参数。该文章提出的减振器为电梯安全可靠运行提供了一种新途径。

铁路货车牵引梁振动频响特性分析

铁路货车牵引梁是轨道车辆运行过程中的重要系统部件,该部件受结构振动影响显著。通过有限元理论和频响理论相结合进行牵引梁有限元分析,基于模态叠加法对牵引梁做频率响应分析,获取牵引梁的变形频响曲线,同时关注固有频率对频响函数峰值的影响,从而使得频响分析结果更为准确。

基于阶跃激励响应的牵引电机定子早期匝间短路故障诊断方法

为了实现对牵引电机定子绕组匝间短路早期故障的可靠诊断,文章提出了一种基于阶跃激励稳态响应电流的故障诊断方法。首先根据牵引电机三相定子绕组匝间短路模型,对定子绕组任意两相施加阶跃激励,推导出3种情况下的响应电流表达式,并依据响应电流稳态值的变化特征提出新的故障特征分量;然后,搭建故障电机仿真模型,分析短路电阻和短路故障严重程度对响应电流的影响,研究故障特征分量对早期匝间短路故障诊断的有效性与可靠性;最后搭建试验平台,分析当电机固有不对称时,匝间短路故障对故障特征分量的影响。仿真与试验结果表明,该故障特征分量可以表示早期的匝间短路故障及其严重程度,并且能滤除电机固有不对称的影响。基于阶跃激励稳态响应电流的诊断方法操作便捷,结果可靠性高,对保护牵引系统的安全具有极大意义,且具备极大的工程应用价值。

升力翼高速列车曲线通过时的轮轨黏着性能研究

建立考虑轮轨关系、升力翼及流场耦合特性等因素的车辆系统动力学模型,分析升力翼高速列车曲线通过时的运动姿态和轮轨接触特性响应,研究列车在曲线轨道运行的轮轨黏着性能,探讨轨道不平顺、曲线半径、运行速度及轮轨接触条件对轮轨黏着性能的影响。研究结果表明:气动升力通过改变列车运行动态响应和轮轨接触特性导致内、外侧轮轨垂向力和纵向蠕滑力重新分配,促使内侧轮更易失去黏着;气动升力和运行速度的增大均会劣化轮轨黏着性能,但曲线半径的增大将显著提升轮轨黏着水平;轨道不平顺削弱了轮轨黏着性能,干态、湿态、油态条件下的轮轨黏着性能依次恶化。列车牵引运行时,干态、湿态、油态条件下的轮轨均能满足牵引力安全限值要求,但制动运行时,湿态和油态条件下的轮轨均不能满足制动力安全限值要求。研究结果可为超高速列车的安全运行与节能设计提供技术支持。

AEB工况下驾驶员姿态对损伤风险的影响

有无紧急制动(AEB)的正面碰撞工况中驾驶员姿态对运动学响应及损伤风险具有重要影响。本文采用THUMS(Ver.6.1)人体有限元模型建立了标准、后仰和前倾等3种驾驶姿态,搭建了正面碰撞约束系统模型,进行了6组50 km/h的仿真实验,对比分析驾驶员不同姿态在有和无AEB作用下的运动学响应以及驾驶员头、胸部损伤参数。结果表明:在有和无AEB介入时,后仰姿态的头部损伤风险均最高,其中有和无AEB介入的HIC_(15)分别为817.5和626.9。AEB的介入对驾驶员胸部压缩量影响最大,3种姿态的胸部压缩量分别增大了89%、115%和22%,后仰姿态胸部压缩量损伤最严重。研究结果厘清了驾驶姿态与AEB对驾驶员运动学响应以及头、胸部损伤的影响,为汽车约束系统和AEB的开发与设计提供了参考价值。

煤矿提升机中机电制动系统技术研究

阐述了矿井提升机的机电制动原理,给出了机电制动器的详细参数和制动性能。此外,设计开发了一个大负载、高响应的机电制动试验平台。试验结果表明,设计的机电制动器制动误差小于9%,制动间隙消除时间小于0.1 s。电机电流输入与制动正压输出呈线性关系,斜率为4.11,截距为0.58,满足矿井提升机正压要求。螺杆位移输出和制动压力输出呈三次函数关系,零误差较小。

面向3min追踪间隔的400 km/h高速列车追踪过程仿真分析

将高速铁路运营速度提高至400km/h有利于提升旅行速度和旅客运输效率。但速度提高会影响追踪间隔,导致能力降低。在梳理高速铁路列车追踪间隔影响因素的基础上,构建了基于距离步长的高速铁路列车追踪运行多智能体仿真模型。通过仿真实验,计算了不同目标速度下的追踪间隔,并分析了各种追踪间隔随目标速度变化的趋势,以及出发及到达追踪间隔对列车牵引制动性能提升的响应情况。实验结果表明,在目标速度400km/h和采用中国标准动车组为基础模拟的牵引制动性能的仿真场景下,列车的区间追踪间隔在3min以内,而出发追踪间隔和到达追踪间隔均大于3min;若提升列车牵引加速度与制动减速度,则可以使列车出发及到达追踪间隔控制在3min以内。

地佐辛与纳布啡预防吻合器痔上黏膜环切术内脏牵拉反应的临床效果观察

目的 观察地佐辛与纳布啡预防蛛网膜下腔阻滞麻醉下行吻合器痔上黏膜环切钉合术(procedure for prolapse and hemorrhoids,PPH)时患者内脏牵拉反应的临床效果。方法将80例在蛛网膜下腔阻滞麻醉下,行PPH的患者随机分为地佐辛组(n=40)和纳布啡组(n=40)。经B超引导定位标记腰椎3~4间隙,进行穿刺麻醉,手术开始时,地佐辛组单次静脉注射地佐辛0.15mg/kg,纳布啡组单次静脉注射纳布啡0.08mg/kg。观察并比较术前(T1)、置入固定扩肛器时(T2)、旋紧吻合器时(T3)及手术结束时(T4)两组患者生命体征(HR、SBP、DBP、SpO_(2))的变化。同时观察两组患者手术时牵拉反应的程度及术后不良反应发生情况。结果两组患者T1~T4时HR、SBP、DBP、SpO_(2)比较,差异均无统计学意义(P>0.05)。两组患者T1时SpO_(2)较T2~T4时低(P<0.05)。地佐辛组T3时HR、SBP、DBP较T1、T2、T4时明显升高(P<0.01);T4时HR、SBP、DBP较T3时升高(P<0.05)。纳布啡组T3时HR、SBP、DBP较T1、T2时升高(P<0.05);T4时HR、DBP较T2时明显下降(P<0.01);T4时SBP、DBP较T3时下降(P<0.05)。两组患者T1、T4时HR、SBP、DBP比较,差异均无统计学意义(P>0.05)。地佐辛组T3时HR、SBP、DBP较T1、T2、T4时明显升高(P<0.01)。纳布啡组T3时SBP、DBP较T1、T2、T4时明显升高(P<0.01)。纳布啡组T2时HR较T1、T3、T4时明显下降(P<0.01)。地佐辛组T2时HR较纳布啡组升高(P<0.05或P<0.01)。两组脉搏氧饱和度差异无统计学意义(P>0.05)。地佐辛组术中牵拉反应程度高于纳布啡组(P<0.01)。两组患者眩晕差异无统计学意义(P>0.05)。结论蛛网膜下腔阻滞PPH术中辅助使用纳布啡能取得较地佐辛更佳的疗效,患者的牵拉反应和不良反应更少,舒适度更高,是一种安全有效的麻醉方式,值得临床推荐。

磁浮管轨直线感应电机牵引悬浮协同优化设计

在磁浮管轨运输系统中,采用悬浮电磁铁与直线感应电机(linear induction motor,LIM)同平面安装方案,可有效减小盾构面积,降低建设成本;同时,LIM法向力能够提供辅助悬浮力,提高系统综合能效。围绕牵引力与法向力协同优化中建模求解误差大、优化复杂等问题,提出一种基于响应面法的一体化LIM优化设计方法。首先,确立牵引力及法向力设计目标,完成电机初始设计。其次,结合Box-Behnken试验设计法和方差分析法,分析电机参数对牵引力和法向力的影响规律,确定敏感参数集。再次,利用响应面法建立关于敏感参数的二阶代理模型,并通过了模型拟合度检验。在加工精度与电机饱和等约束下,通过二代非支配排序遗传算法对代理模型进行多目标寻优。最后,利用Maxwell软件对优化前后的电机进行时步有限元仿真。结果表明,在工频、额定电流15 A的工况下,初始电机的牵引力和法向力分别为305.9和-60.5 N,优化后为309.4和-309.3 N,优化后性能指标显著提升,设计误差分别为3.13%和3.10%,表明了协同优化设计方法切实有效。

基于虚拟仿真技术的液压盘式制动系统性能分析

为确保液压制动系统的可靠性,基于虚拟仿真技术,对液压系统的动力响应和盘式制动器的热力学特性进行了研究和分析。根据液压加载机理推导出有效制动压力计算方法,在恒压制动条件下,基于Car Sim得出分时控制和并行控制方案的轮缸压力响应。采用热机耦合方法,基于ABAQUS得出风冷盘式制动器的瞬态温度场和应力场。研究结果表明,分时控制可实现更短的制动周期,并行控制能够获得更高的轮缸压力,制动系统的效能较高。

某乘用车制动盘温升分析与优化设计

为了得到满足温升要求且质量轻的制动盘结构,同时也为制动盘的温升优化设计开发提供理论依据,以某乘用车通风前制动盘为研究对象,创建制动盘的单次制动温升和连续10次制动温升的有限元瞬态热仿真分析模型,将制动盘的结构参数作为制动盘温升优化分析的设计变量,建立制动盘温升响应面分析模型,采用遗传算法以制动盘的温升为约束条件,质量最小为目标,对制动盘温升分析的响应面模型进行优化。结果表明,基于响应面分析模型得到的制动盘温升优化结果具有较高的可靠度,其中优化后的制动盘单次制动温升为93.4℃,连续10次制动温升为375.9℃,同时优化后的制动盘分别基于响应面分析模型和有限元瞬态热仿真分析模型计算得到的制动盘质量、单次制动结束时的温度、第10次循环制动结束时的温度结果的误差分别为1.05%、0.48%、0.32%,误差值均在可接受范围内。

固相萃取-液相色谱-串联质谱法测定污水中8 种新烟碱类农药

新烟碱类农药作为一类新型农药,由于其对非靶标生物造成生态风险而引起广泛关注。为了实现污水中痕量新烟碱类农药的快速、准确定量,本研究建立了同时检测污水中8种新烟碱类农药(呋虫胺、E-烯啶虫胺、噻虫嗪、噻虫胺、吡虫啉、氯噻啉、啶虫脒和噻虫啉)的固相萃取-液相色谱-串联质谱法。确定选择色谱流动相类型和质谱参数后,采用单因素法确定固相萃取(SPE)的条件:萃取柱类型为HLB(500 mg/6 mL),上样体积为500 mL,上样速度为10 mL/min,样品pH为6~8。通过优化色谱梯度洗脱程序、样品的稀释倍数并采用同位素内标定量法降低污水样品的基质效应,确定污水稀释5倍进行前处理,采用ZORBAX Eclipse Plus C18色谱柱(100 mm×21 mm,18μm),以含01%甲酸的2 mmol/L乙酸铵水溶液和甲醇为流动相进行梯度洗脱,在正离子多反应监测模式下分析10 min,用吡虫啉-d4作为同位素内标进行定量。通过响应曲面法进一步优化SPE的淋洗液及洗脱液类型和用量,确定用10%甲醇水溶液淋洗,7 mL甲醇-乙腈(1∶1,v/v)混合溶液洗脱。8种新烟碱类化合物在相应范围内线性关系良好(线性相关系数(r)均大于09990),方法检出限(MDL)为02~12 ng/L,方法定量限(MQL)为08~48 ng/L,在低、中、高3个加标水平下的加标回收率为826%~942%,RSD为39%~94%。该方法成功用于4个城镇污水处理厂进水水样的分析,8种新烟碱类农药的检出含量为ND~256 ng/L。与类似方法相比,该方法检出限低,准确度高,适用于污水中8种新烟碱类农药的痕量检测。

Revealing driver psychophysiological response to emergency braking in distracted driving based on field experiments

Purpose–The purpose of this paper is to characterize distracted driving by quantifying the response time and response intensity to an emergency stop using the driver’s physiological states.Design/methodology/approach–Field tests with 17 participants were conducted in the connected and automated vehicle test field.All participants were required to prioritize their primary driving tasks while a secondary nondriving task was asked to be executed.Demographic data,vehicle trajectory data and various physiological data were recorded through a biosignalsplux signal data acquisition toolkit,such as electrocardiograph for heart rate,electromyography for muscle strength,electrodermal activity for skin conductance and force-sensing resistor for braking pressure.Findings–This study quantified the psychophysiological responses of the driver who returns to the primary driving task from the secondary nondriving task when an emergency occurs.The results provided a prototype analysis of the time required for making a decision in the context of advanced driver assistance systems or for rebuilding the situational awareness in future automated vehicles when a driver’s take-over maneuver is needed.Originality/value–The hypothesis is that the secondary task will result in a higher mental workload and a prolonged reaction time.Therefore,the driver states in distracted driving are significantly different than in regular driving,the physiological signal improves measuring the brake response time and distraction levels and brake intensity can be expressed as functions of driver demographics.To the best of the authors’knowledge,this is the first study using psychophysiological measures to quantify a driver’s response to an emergency stop during distracted driving.

全自动运行线路列车自动对位调整功能测试研究

[目的]全自动运行线路列车JOG(自动对位调整)的可靠性与列车停站精度直接相关,需加强JOG功能测试验证。[方法]以上海轨道交通15号线为例,分析了列车JOG功能故障原因,提出了提高JOG可靠性的优化方案,以及新线JOG功能测试验收方法。[结果及结论]对于既有线,可通过优化列车轻级制动参数提高JOG的可靠性。对于新建线路,可通过不同牵引极位和不同列车轻级制动参数下的测试,得到符合线路实际运营情况和列车特性的最佳值,以保障JOG功能;同时,为确保JOG功能的稳定性,需对欠标或冲标0.5~2.0 m以及2.0~5.0 m两种情况分别进行测试验证。

列车运行牵引制动故障分类的随机森林算法设计与验证

列车的运行安全对轨道交通的可持续发展至关重要。牵引制动系统的故障可能导致严重的安全问题和运行延误。通过准确检测运行中的牵引制动故障,可以提高列车安全性,降低事故发生的可能性。本研究旨在提高列车运行牵引制动故障的诊断分类准确性与有效性。首先,基于时序特征的数据分析列车牵引制动故障数据集。设计数据重采样逻辑和特征提取方法,解决原始数据类别不平衡的问题,实现了显著的性能提升。实验表明,在使用相同的数据规模进行机器学习训练时,各个机器学习模型的分类性能均提升了10%以上。接着,建立基于SVM和决策树的机器学习模型,对数据集进行故障分类识别,并通过网格搜索进行超参数调整。此外,尝试多种基于基础分类算法的集成学习策略,并对所设计的模型进行仿真验证。其中,随机森林算法表现突出,测试准确率达到96.12%。通过分析分类报告和混淆矩阵,验证该方法的有效性和可靠性,为列车运行牵引制动故障诊断提供一种新的解决方案。