基于混合约束自编码器的机动车工况智能构建方法

为构建更具代表性的机动车行驶工况，实测采集福州地区1辆机动车共20d的真实驾驶数 据，选取14个特征参数表征运动学片段信息，运用主成分分析和K-means聚类划分运动学片段聚类，根据聚类中心的距离筛选备选片段并随机组合构建工况集合。提取11个特征参数计算构建工况的误差，选择集合中误差最小的工况作为构建工况，提出利用混合约束自编码器构建工况优化模型，并研究参数标定方法，最终将平均误差由2.97%缩小到2.39%。混合约束自编码器模型的分析验证结果表明，优化策略符合实际情况，可以有效避免随机选择带来的误差不确定性，验证了所提出行驶工况构建流程的合理性，并提升了工况预测的精确度，得到模型参数推荐值。对实现碳达峰目标下的机动车碳排放预测及排放控制具有重要的现实作用和意义。     

Optimal development of alternative fuel station networks considering node capacity restrictions

A potential solution to reduce greenhouse gas (GHG) emissions in the transport sector is the use of alternative fuel vehicles (AFV). As global GHG emission standards have been in place for passenger cars for several years, infrastructure modelling for new AFV is an established topic. However, as the regulatory focus shifts towards heavy-duty vehicles (HDV), the market diffusion of AFV-HDV will increase as will planning the relevant AFV infrastructure for HDV. Existing modelling approaches need to be adapted, because the energy demand per individual refill increases significantly for HDV and there are regulatory as well as technical limitations for alternative fuel station (AFS) capacities at the same time. While the current research takes capacity restrictions for single stations into account, capacity limits for locations (i.e. nodes) – the places where refuelling stations are built such as highway entries, exits or intersections – are not yet considered. We extend existing models in this respect and introduce an optimal development for AFS considering (station) location capacity restrictions. The proposed method is applied to a case study of a potential fuel cell heavy-duty vehicle AFS network. We find that the location capacity limit has a major impact on the number of stations required, station utilization and station portfolio variety.     

Extending Time to Collision for probabilistic reasoning in general traffic scenarios

Vehicle-to-vehicle communication systems allow vehicles to share state information with one another to improve safety and efficiency of transportation networks. One of the key applications of such a system is in the prediction and avoidance of collisions between vehicles. If a method to do this is to succeed it must be robust to measurement uncertainty and to loss of communication links. The method should also be general enough that it does not rely on constraints on vehicle motion for the accuracy of its predictions. It should work for all interactions between vehicles and not just a select subset. This paper presents a method to calculate Time to Collision for unconstrained vehicle motion. This metric is gated using a novel technique based on relative vehicle motion that we call “looming”. Finally, these ideas are integrated into a probabilistic framework that accounts for uncertainty in vehicle state and loss of vehicle-to-vehicle communication. Together this work represents a new way of considering vehicle collision estimation. These algorithms are validated on data collected from real world vehicle trials.     

快速重载运输趋势下的城轨车辆技术发展特征

随着城市化的进程,城轨交通客流强度不断增大,发车间隔不断压缩,使得我国城轨交通呈现出快速、重载、智能的发展趋势。文章结合我国目前城轨车辆快速、重载的发展状况,提出城轨车辆最大轴重的概念和建议值,且应按最大轴重对承载结构件进行设计,详细分析了城轨车辆结构件的技术发展特征,并建议应及时检测和维护车轮和钢轨,降低车、轨的振动和噪声,以提高车、轨的综合使用寿命。     

Hybrid analytic-FEM approach for dynamic response analysis of air-cushion vehicle skirts

Focused on the assessment method for dynamic behavior of the skirts of an air cushion vehicle (ACV), this paper proposes a hybrid analytic-FEM approach, within which the self-developed subroutine considers the transient skirt-water contacting force through suggested semi-analytical formula based on the empirical results from CFD simulations of the equivalent flat-plate model. The dynamic explicit algorithm of FEM is adopted to solve the large deformation problem of flexible skirts. The validity of the approach has been confirmed by comparing with previous numerical results as well as published experimental results of steady seal deformation tests at University of Michigan. Afterward, more simulations for demonstration cases are carried out to study the complex dynamic response of the skirts under different skirt-water contacting conditions. The proposed method can obtain more reliable results than traditional analytical method and be more efficient than fluid-structure interaction simulations, thus providing a practical balanced approach aiming at the dynamic response analysis for whole skirts and contributing to the skirts dynamics performance assessment of an ACV.     

周家嘴路车流起动波速统计研究

通过实际观测和统计分析 ,论证了平面交叉口红灯转绿灯时车流起动波速可以满足正态分布假设 ,更可以满足泊松分布假设 ,后者拟合优度高于前者。揭示了在周家嘴路条件下 ,随着车辆排队长度增加 ,起动波速会相应变大 ,呈负指数规律上升的趋势 ,与低速混合路段有明显差异。据此建议 ,如将交通流动力学模型应用于高速公路或城市高架道路一类问题时 ,状态指数取值在 2 .5左右为好。     

Robust Spectral Estimation of Track Irregularity

Because the existing spectral estimation methods for railway track irregularity analysis are very sensitive to outliers, a robust spectral estimation method is presented to process track irregularity signals. The proposed robust method is verified using 100 groups of clean/contaminated data reflecting he vertical profile irregularity taken from Bejing-Guangzhou railway with a sampling frequency of 33 data every 10 m, and compared with the Auto Regressive (AR) model. The experimental results show that the proposed robust estimation is resistible to noise and insensitive to outliers, and is superior to the AR model in terms of efficiency,, stability and reliability.     

Delphi环境下PMAC数据实时采集和显示

为了实现对运动轨迹模拟系统中的运动信息实时采集和显示,在研究W in32应用程序与PMAC之间通讯原理和PMAC数据采集方式的基础上,提出了利用Delph i实现PMAC数据的实时采集和显示.在运动轨迹模拟系统中利用该技术,获得了很好的效果.     

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以车辆调度问题为实例引出一种新的组合优化算法，并与原有的方法进行比较，说明新方法可以有效地抑制组合爆炸，极大地提高算法寻优效率.然后，本文用数学方法来证明该新方法再寻优上的正确性，最后根据两种不同算法编写各自对应的程序，用实际运行的结果来验证新算法带来的效率的提高.     

车辆优化调度问题的研究现状评述

本文介绍了国内外车辆优化调度问题的研究现状，对问题的分类、模型构造，求解算法及其适用范围等进行了分析，此外，还对作者自己的研究成果作了简要阐述。