A new model for temporal–spatial stochastic analysis of vehicle–track coupled systems

The vehicle–track coupled system has a random nature in the time–space domain. This paper proposes a computational model to analyse the temporal–spatial stochastic vibrations of vehicle–track systems, where the vehicle–track system is divided into a vehicle subsystem, track subsystem, and interfacial subsystem between the wheel and rail. In this model, the time-varying randomicity of dynamical parameters of the vehicle system, correlation, and randomness of the track structural parameters in the time–space joint dimensions, and randomness of the track random irregularities are considered. A probability dimension-reduction method was used to randomly combine different random variables. Furthermore, the probability density evolution method was applied to solve the delivery problem of probabilities between excitation inputs and response outputs. The temporal–spatial stochastic vibrations of the vehicle–track system with different coefficients of variation were studied, in which we assumed that the dynamic parameters obeyed the normal distribution, and the stochastic simulation method of the track random irregularities is probed into. The calculated results from this model are consistent with the actual measured results and physical conceptions. Thus, the temporal–spatial stochastic evolutionary mechanism can be explored, and the limits of dynamic indices can be formulated by using this developed model.     

Plate scanning tools to obtain travel times in traffic networks

The management of vehicle travel times has been shown to be fundamental to traffic network analysis. To collect travel time measurement, some methods focus solely on isolated links or highway segments, and where two measurement points, at the beginning and at the end of a section, are deemed sufficient to evaluate users' travel time. However, in many cases, transport studies involve networks in which the problem is more complex. This article takes advantage of the plate scanning technique to propose an algorithm that minimizes the required number of registering devices and their location in order to identify vehicles candidates to compute the travel times of a given set of routes (or subroutes). The merits of the proposed method are explained using simple examples and are illustrated by its application to the real network of Ciudad Real.     

汽车吸能转向机构与驾驶员碰撞的仿真与试验

利用非线性有限元方法建立了可收缩吸能转向机构与驾驶员所组成碰撞系统的仿真模型，深入讨论了碰撞仿真模型初始条件与边界条件的处理方法、材料非线性本构关系的选择、接触对摩擦系数的确定。并按照GB11557规定的要求，对人体模块有限元模型进行了验证。分析计算了吸能转向机构与人体模块碰撞时上下套管间的收缩位移和作用在转向柱上的碰撞力，并通过相应的碰撞台架试验验证了仿真结果的正确性。     

汽车发动机诊断的统计模拟方法

运用统计模拟的方法，提取发动机信号的故障特征，并给出这些特征值的置信区间，实现了故障的定量诊断。在柴油机供油系统和汽车发动机中的诊断实践充分证明了该方法的优越性。     

车辆与工程机械电子液压控制的发展

简要综述了车辆与工程机械中电子液压控制的新进展和需要解决的关键技术问题。提出了实现功率传输和运动控制与综合的新方案，给出了发动机-液压传动装置-负荷最佳匹配的实现方法。以应用于上海磁悬浮高速铁路工程轨道梁运输与搬运的工程机械的计算机控制系统为背景，讨论了基于现场总线控制系统(FCS)和PCI04车载工控机的车辆计算机控制系统的设计方法。     

汽车导航用电子地图的高效路网模型

为了有效地描述实际道路网络，提高汽车导航系统的运行效率，建立了一种新的电子地图的路网模型。在分析了嵌入式系统特点的基础上，对路网的数据结构进行了简化。采用重整实体ID的方法，进一步提高了数据的处理效率。实践证明，该模型可以较好地表述实际的道路网络，结构精练，处理效率高，适合车载导航系统，特别是嵌入式车载导航系统的要求。     

具有模块化结构的汽车动力学仿真模型的初步研究

初步探讨了面向开发型驾驶模拟器的具有模块化结构的汽车动力学仿真模型建立方法，从而可以在此基础上进一步建立一套通用的面向结构的汽车动力学仿真程序，便捷地在开发型驾驶模拟器上实现对不同类型或同类型不同结构车辆性能的仿真。     

基于案例推理的汽车维修专家系统

依据汽车维修行业领域的专家知识和实践经验，综合运用案例推理、模糊推理和缺省推理等方法，对汽车维修中的多种故障采取原因和症状相结合的维修思路进行推理机制的设置，建立基于案例推理、模糊推理和缺省推理相结合的、能迅速确定汽车维修方案的推理模型，建立了某企业汽车维修系统的原型系统。     

城市公交客车发展趋势

本文从未来十年城市社会经济和文化发展的角度分析了公交客车发展的趋势:即动力设计环保化、形体设计大型化、技术配置多样化、性能选择人本化、信息沟通智能化、外观设计艺术化、操作系统自动化、应急设置可靠化、总成寿命同步缩短化、车身结构轻型化。     

BP和RBF神经网络在辨识内燃机燃烧过程中的应用

分析了发动机燃烧过程的研究方式,提出了用BP和RBF网络辨识内燃机燃烧过程的方法。选定神经网络的结构、隐层神经元的作用函数和控制参数,成功地得到了发动机的辨识模型,结果由RBF网络辨识的模型给出,从这一模型可以获得任意点缸内压力和温度以延拓的参数,为排放分析、计算和结构优化提供了良好的基础。