精确测量客车车身高度变化有解了!

正随着乘客对车辆乘坐舒适性要求的提高,以及我国客车悬架技术的发展,空气悬架在客车上的应用日益广泛。传统的空气悬架控制模式是采用机械高度阀,即通过高度阀阀门的开启调节对空气悬架气囊的充放气,从而保持车辆恒定的行驶高度。伴随系统应用的推广和车辆控制技术的发展,电子控制逐渐取代传统的机械控制电子控制系统,不仅提高了操作的舒适性和反应的灵敏度,而且可以附加很多辅助功能。据了解,为了确保悬架的主要特     

电流环法测试管中电流技术应用

由于实际管道中阴极保护电流较小以及现场环境干扰严重,现有的方法难以测得真实的管中电流。文中结合现场案例,通过与电位差法作对比,介绍了电流环法在测量埋地管道管中电流方面的应用。结果表明：电流环法可以测量管道中电流的大小及方向;电流环法与电位差法测得的电流数值基本相同,但电流环法的测量值更稳定;由于地磁场对电流环的影响范围在±100 mA之内,当管中电流小于100 mA时,测试数值正负跳动,无法取值,也不能判断电流方向,电流环法不适用。     

主动悬架系统模式切换控制策略研究

针对在不同工况下车辆行驶时对于主动悬架系统的性能需求,本文设计出一种可切换悬架工作模式的悬架控制策略,可以提高车辆在不同工况下行驶时的动力学性能。通过对控制策略进行建模仿真,结果得出相较于未进行模式切换的悬架,所设计的模式切换控制策略可以有效改善悬架工作时的性能,为后续控制参数的优化提供了研究基础。     

汽车电子控制悬架系统

介绍了汽车的电子控制半主动悬架系统和电子控制主动悬架系统的工作原理。     

杂散电流腐蚀防护与测试

首先介绍了杂散电流的基本概念、特点及分类,接着分析了目前国内外测试杂散电流的两种主要检测技术的工作原理,并且总结了杂散电流测试仪在实际工程中的应用,介绍了杂散电流测试仪的构成和功能特点,分析比较了国内外杂散电流测试仪,最后介绍了各种防护措施的工作原理,同时总结比较了各种措施的优缺点.通过对杂散电流的研究分析,可以为找出主要问题,探索解决的方案,并为降低杂散电流的影响提供了有力参考.     

地铁杂散电流监测系统的工作原理及调试

经过对广州地铁三号线杂散电流监测系统的施工,对其工作原理及调试进行了分析与说明。     

GPS同步中断法在阴极保护有效性评价中的应用

采用GPS同步中断法对港枣线通电/断电电位进行测量,进而根据阴极保护有效准则对港枣线阴极保护有效性进行系统评价。结果表明：干线管道的阴极保护有效保护率达82.5%,调整恒电位仪输出后,干线管道的阴极保护有效保护率可达95.5%。欠保护管段集中在兖州站-滕州17#阀室站间。阴极保护失效可能与管道防腐层出现电流疑似泄漏点及交流杂散电流干扰有关。     

方寸间的磁浮列车

<正>磁浮列车技术历史悠久。早在1934年,德国人赫尔曼·肯佩尔提出电磁浮原理后,获得了世界上第一项有关磁浮技术的专利;法拉第于1821年发明了世界上第一台电动机,直线电机也被描述为旋转电机被展平。两者的提出为磁浮列车的诞生打下了基础。人类对于高速轨道交通的追求始终不渝。将电磁浮技术和直线电机技术相结合,诞生了磁浮列车技术。1970年3月7日,法国为在奥尔良(Orleans)进行"飞行列车"试验成功发行了纪念邮票,图1是     

资源节约型的直线电机轮轨交通系统

采用直线感应电机驱动的直线电机轮轨交通系统具有车辆断面小、轴重轻、爬坡能力强、曲线半径小、噪音低、振动小、能耗低、污染小、维修少、安全性能好等优点,非常适合大中城市中等运量城市轨道交通发展的要求。本文通过对直线电机轨道交通系统在土地占用、工程造价、运营成本、能源消耗、环境影响等方面的资源消耗特点进行分析比较。指出其是资源节约型的城市轨道交通模式。     

汽车电气系统寄生电流的检测与控制

汽车在日常使用和维修中能使电子元件、控制模块性能会下降,线路的各个插接件之间会产生松动等。这都能使汽车电气系统的寄生电流增加,造成蓄电池损坏和火灾的危险性。所以经常检测电气系统的寄生电流尤为重要。     

汽车电动助力转向系统控制策略的研究

文章系统阐述了电动助力转向系统的控制策略和控制方法。通过比较电压控制方式和电流控制方式,得出电流控制方式明显优于电压控制方式的结论;并重点分析了在电流控制方式下的控制策略(包括助力控制、回正控制和阻尼控制),并在SIMULINK中进行了仿真。     

杂散电流测绘仪在埋地钢质管道杂散电流检测中的应用

研究了杂散电流干扰的检测方法及对其干扰程度的评价方法，通过对杂散电流干扰成因和特点的分析，选择杂散电流测绘仪（SCM）作为检测和评价的手段。杂散电流测绘仪是一种智能化的测量仪器，通过后处理软件对采集的数据进行分析就可以获得管线周围杂散电流波形图及干扰数据，对杂散电流的测量与分析有助于掌握管线附近杂散电流情况及制定腐蚀控制策略。该仪器已经在工程中得到了很好的应用，取得了良好的效果。     

智能型阀门电动执行机构控制器的研制

介绍了一种具有新型的阀门电动执行机构的智能控制器的设计与开发。该控制器采用DSP作为主控制单元,采用矢量控制策略控制感应电动机,组成了一个集本地控制、远程控制、状态指示等功能于一体的智能系统,适用于各类工业控制阀。     

并联混合动力汽车改进模糊控制策略研究

本文提出一种兼顾电池SOC限值方法的混合动力汽车多种群遗传模糊控制策略。引入模糊逻辑控制以增强整车控制系统鲁棒性、实时性;用多种群遗传算法对模糊变量隶属度函数进行优化,使在模糊逻辑控制下整车燃油消耗得到降低;使用电池SOC限值方法避免电池在SOC过低时继续放电。利用matlab平台联合advisor软件进行联合仿真实验,仿真结果表明多种群遗传模糊模糊控制策略能够比advisor软件默认的电机辅住控制策略燃油经济性提高6.96%的情况,SOC限值方法使电池工作在更加合理的SOC值区间范围内,有效保护电池。     

Maximizing airborne delay at no extra fuel cost by means of linear holding

This paper introduces a linear holding strategy based on prior works on cruise speed reduction, aimed at performing airborne delay at no extra fuel cost, as a complementary strategy to current ground and airborne holding strategies. Firstly, the equivalent speed concept is extended to climb and descent phases through an analysis of fuel consumption and speed from aircraft performance data. This gives an insight of the feasibility to implement the concept, differentiating the case where the cruise flight level initially requested is kept and the case where it can be changed before departure in order to maximize the linear holding time. Illustrative examples are given, where typical flights are simulated using an optimal trajectory generation tool where linear holding is maximized while keeping constant the initially planned fuel. Finally, the effects of linear holding are thoroughly assessed in terms of the vertical trajectory profiles, range of feasible speed intervals and trade-offs between fuel and time. Results show that the airborne delay increases significantly with nearly 3-fold time for short-haul flights and 2-fold for mid-hauls to the cases in prior works.     

Perimeter and boundary flow control in multi-reservoir heterogeneous networks

In this paper, we macroscopically describe the traffic dynamics in heterogeneous transportation urban networks by utilizing the Macroscopic Fundamental Diagram (MFD), a widely observed relation between network-wide space-mean flow and density of vehicles. A generic mathematical model for multi-reservoir networks with well-defined MFDs for each reservoir is presented first. Then, two modeling variations lead to two alternative optimal control methodologies for the design of perimeter and boundary flow control strategies that aim at distributing the accumulation in each reservoir as homogeneously as possible, and maintaining the rate of vehicles that are allowed to enter each reservoir around a desired point, while the system’s throughput is maximized. Based on the two control methodologies, perimeter and boundary control actions may be computed in real-time through a linear multivariable feedback regulator or a linear multivariable integral feedback regulator. Perimeter control occurs at the periphery of the network while boundary control occurs at the inter-transfers between neighborhood reservoirs. To this end, the heterogeneous network of San Francisco is partitioned into three homogeneous reservoirs and the proposed feedback regulators are compared with a pre-timed signal plan and a single-reservoir perimeter control strategy. Finally, the impact of the perimeter and boundary control actions is demonstrated via simulation by the use of the corresponding MFDs and other performance measures. A key advantage of the proposed approach is that it does not require high computational effort and future demand data if the current state of each reservoir can be observed with loop detector data.     

Design and evaluation of dynamic traffic management strategies for congested conditions

This paper presents a procedure for dynamic design and evaluation of traffic management strategies in oversaturated conditions. The method combines a dynamic control algorithm and a disutility function. The dynamic algorithm designs signal control parameters to manage formation and dissipation of queues on system links with explicit consideration of current and projected queue lengths and demands. The disutility function measures the relative performance of the dynamic control algorithm based on preset system performance goals. The user may statically select the management strategy, or alternatively the system may be instructed to set off different management schemes based on predefined performance thresholds. The problem was formulated as one of output maximization subject to state, control, and traffic management strategy choices. Solutions were obtained using genetic algorithms. Four traffic management plans were tested to show the capabilities of the new procedure. The results show that the procedure is able to generate suitable signal control schemes that are favorable to attaining the desired traffic management goals. The results showed that multiple, or hybrids of single measures of effectiveness may need to be examined in order to correctly assess system performance. The procedure has potential for real-time implementation in an intelligent transportation system setting.     

使役条件下二轮电动车电池单次耐用性研究

本文通过理论和实验相结合的方法对使役条件下,在不同坡度、路面道路条件,不同充放电时间、制动次数、轮胎胎压、载重量等使用情况对二轮电动车电池的单次耐用性进行试验研究。结果发现,造成电机输出功率增加,放电电流增大的外部条件均会造成蓄电池容量减少,研究结果可指导二轮电动车车主合理科学使用二轮电动车。     

Cost damping and functional form in transport models

Transport models allowing for cost damping are characterised by marginally decreasing cost sensitivities in demand. As a result, cost damping is a model extension of the simple linear-in-cost model requiring an appropriate non-linear link function between utility and cost. The link function may take different forms and be represented as a non-linear-in-parameter form such as the well-known Box–Cox function. However, it could also be specified as non-linear-in-cost but linear-in-parameter forms, which are easier to estimate and improve model fit without increasing the number of parameters. The specific contributions of the paper are as follows. Firstly, we discuss the phenomenon of cost damping in details and specifically why it occurs. Secondly, we provide a test of damping and an easy assessment of the (linear) damping rate for any variable by estimating two auxiliary linear models. This turns out to be an important guidance as the damping rate largely dictates which link functions are appropriate for the data. Thirdly, inspired by the Box–Cox function, we propose alternative linear-in-parameter link functions, some of which are based on interpolation of approximate Box–Cox end points, and others which are inspired by Taylor Expansions. The different functions are tested in simulation experiments and subsequently in a large-scale demand model based on more than 22,000 revealed preference observations. It is concluded that the use of properly specified linear-in-parameter functions gives good data fit and sometimes even outperforms the Box–Cox functions without increasing the number of parameters.