车辆四轮相关路面非平稳随机输入通用时频模型

车辆非匀速行驶时路面的随机输入模型是汽车非平稳动力学分析研究的重要基础.首先应用等效协方差方法建立了单轮随机输入非平稳时域模型.根据时间-空间一、二阶微分关系,成功地解决了前后轮变时差相关的问题,并由各向同性假设直接得到了与车辆轮距有关的左右轮相干函数,无需实测相干函数,因此适合各种车辆.本文还应用Wigner-Ville谱分析了路面非平稳随机输入的瞬时功率谱.分析表明Wigner-Ville谱很好地反映了频率特征和路面波形特征.     

使用特征正交分解型谱表示法的汽车受路面激励随机模拟

将特征正交分解型谱表示法用于模拟汽车受路面激励。首先给出了路面不平度对汽车输入的位移随机激励的谱描述。基于路面激励的功率谱矩阵,结合特征正交分解（POD,Proper Orthogonal Decomposition,）型谱表示法的模拟表达式,给出了路面激励的显式POD分解,定义了汽车的“路面激励模态”,推导了路面对汽车输入激励随机模拟的简化计算公式。该方法可用FFT来减少计算量以提高计算速度。它由于完全消除掉了原型谱表示法的Cholesky分解过程而具有较高的计算效率和更明确的物理意义。最后,通过对一个四轮轿车在国标GB7031—87中的A级路面不平度下受到的位移随机激励进行模拟,说明了该方法的有效性。     

基于车辆振动响应反向分析的路面等级辨识方法

提出一种利用希尔伯特黄变换和概率神经网络进行车辆振动响应反向分析的路面等级辨识方法,为主动悬架控制提供有效信息。建立车辆模型和随机输入路面模型,利用希尔伯特黄变换对不同等级路面下的车辆振动响应仿真数据进行分解变换,得到车辆振动响应的瞬时能量;提取瞬时能量的敏感特征参数,利用概率神经网络训练路面分类器,确定路面等级与特征参数范围的映射关系,完成路面等级分类器的设计;利用加速度传感器采集车辆在典型路面下的振动响应数据,提取试验数据的特征参数,并将其输入到训练完成的路面分类器中,实现试验路面等级辨识。辨识结果表明,基于车辆振动响应的反向分析法,结合希尔伯特黄变换和概率神经网络,可以实现对车辆当前行驶路面等级的辨识。     

基于车辆振动响应反向分析的路面等级辨识方法EI北大核心CSCD

提出一种利用希尔伯特黄变换和概率神经网络进行车辆振动响应反向分析的路面等级辨识方法,为主动悬架控制提供有效信息。建立车辆模型和随机输入路面模型,利用希尔伯特黄变换对不同等级路面下的车辆振动响应仿真数据进行分解变换,得到车辆振动响应的瞬时能量;提取瞬时能量的敏感特征参数,利用概率神经网络训练路面分类器,确定路面等级与特征参数范围的映射关系,完成路面等级分类器的设计;利用加速度传感器采集车辆在典型路面下的振动响应数据,提取试验数据的特征参数,并将其输入到训练完成的路面分类器中,实现试验路面等级辨识。辨识结果表明,基于车辆振动响应的反向分析法,结合希尔伯特黄变换和概率神经网络,可以实现对车辆当前行驶路面等级的辨识。     

时空相关路面不平度时域模型仿真研究

路面不平度时域模型对现代汽车理论研究意义重要。应用谐波叠加法建立单轮路面不平度输入模型,提出两种不同轮辙路面空间相关模型,并结合同轮辙路面不平度输入时间延迟关系,将单轮模型拓展为四轮路面不平度时域模型。仿真分析显示,该两种方法建立的路面不平度模型,其功率谱与理论功率谱基本吻合,异轮辙输入相干函数符合理论规律。与其它方法相比,该模型建模效率高。     

典型路面的提取与合成方法研究

介绍了道路路面数据测量系统的构成和数据预处理方法。针对测量的道路路面数据,提取了可表征路面特点的特征参数,包括基本统计量、国际平整度指数和功率谱密度参数等。在此基础上,使用雷达图统计分析工具,提出了典型路段的提取与合成算法。并以北京地区真实的海量路面测量数据为例,进行了典型路面的提取与合成,得到了可反映和表征该地区路面特点的典型路面。最后总结了典型路面的提取与合成方法,展望了其应用前景。     

沥青混凝土路面压实技术的控制措施

良好的路面质量最终要通过碾压来实现,因此必须重视压实工作,深入研究压实质量的控制技术.本文通过实际经验,探讨了沥青混凝土路面压实技术控制措施.     

公路路面施工工艺及质量控制分析

公路路面工程是公路工程中最重要的一个环节,是工程质量的关键,它对行驶速度、安全性都有影响,是对工程质量直观和客观的评价。本文结合某公路路面分析了公路路面施工工艺特点及要点,并提出相应的质量控制措施来确保路面的施工质量。     

概率密度导数在工程上的应用分析

本文通过对路面砼强度抽样分布规律的分析,运用概率论原理和数理统计方法,导出了路面砼强度的概率密度函数,并证明这种函数是正态分布概率密度函数。     

浅谈沥青砼路面平整度的质量控制

道路工程是基础设施建设的重要组成部分.路面平整度是评价路面使用性能的一个重要指标,它直接影响着车辆在路面上的行驶质量和道路基本功能的充分发挥.因此路面平整度的改善和提高,一直作为沥青砼路面施工中的一项关键技术而受到道路建设者的关注和重视.     

Scale and skew‐invariant road sign recognition

A fast and robust method to detect and recognize scaled and skewed road signs is proposed in this paper. In the detection stage, the input color image is first quantized in HSV color model. Border tracing those regions with the same colors as road signs is adopted to find the regions of interest (ROI). The ROIs are then automatically adjusted to fit road sign shape models so as to facilitate detection verification even for scaled and skewed road signs in complicated scenes. Moreover, the ROI adjustment and verification are both performed only on border pixels; thus, the proposed road sign detector is fast. In the recognition stage, the detected road sign is normalized first. Histogram matching based on polar mesh is then adopted to measure the similarity between the scene and model road signs to accomplish recognition. Since histogram matching is fast and has high tolerance to distortion and deformation while contextual information can still be incorporated into it in a natural and elegant way, our method has high recognition accuracy and fast execution speed. Experiment results show that the detection rate and recognition accuracy of our method can achieve 94.2% and 91.7%, respectively. On an average, it takes only 4–50 and 10 ms for detection and recognition, respectively. Thus, the proposed method is effective, yet efficient. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 28–39, 2007     

汽车动力总成悬置耐久性模拟试验研究

探讨了悬置道路模拟实验中频响函数的建立和路谱迭代方法。以某款轿车的发动机液压悬置为研究对象,在试验场采集了悬置的道路载荷谱。通过基于远程控制参数技术（RPC）对发动机悬置道路载荷谱进行了重构,重构的道路载荷谱达到了预期的精度要求。论述了建立悬置路谱模拟试验的总载荷序列的方法。应用文中的方法,在MTS831试验台架上对液压悬置进行了道路模拟耐久性试验,试验结果表明,所采用方法可成功用于悬置耐久性试验。     

Current approaches to quantify the longitudinal road roughness

Paper summarised the proposals of fourteen new alternative indexes intended for road roughness evaluation of longitudinal road profile, which have been introduced in the last decade approximately. The main advantages of proposed indexes are: (1) effort to reflect the most of ride quality aspects such as ride comfort, ride safety and dynamic load of road or cargo; (2) using the in situ measurements of vibration response or subjective perception of vibration; (3) effort to reflect the vehicle responses such as roll and pitch vibration, or longitudinal and lateral vibration; (4) effort to detect the critical parts of road in a spatial domain; and (5) effort to reflect a vehicle velocity. The main limitations of proposed indexes are: (1) many proposals are only alternative to the international roughness index (IRI) or are based on the IRI procedure; (2) a simple one-dimensional vehicle model is often used with the constant parameters and velocity; and (3) orientation to one vibration response category as ride comfort.     

3D road modeling via the integration of large-scale topomaps and airborne LIDAR data

Abstract

Modern road systems have become complex networks with multiple layers, making three- dimensional (3D) road modeling an important task in the geoinformatic realm. Although traditional topographic maps contain explicit planimetric networks, they often lack sufficient elevation information to describe the vertical alignments in multi-layer road systems. In this investigation, we combine data from large-scale topographic maps and airborne light detection and ranging (LIDAR) data to reconstruct 3D road models. The proposed scheme includes two steps: planimetric networking and surface modeling. In the first part, road centerlines are determined then linked up and their topologies organized using the polylines extracted from large-scale topographic maps. In the second part, a filter is utilized for the extraction of road surface points from airborne LIDAR data. The three dimensional alignment of the profiles and cross-sections is then computed. Furthermore, to improve the realism of the road models, surfaces are constrained by continuities of slope and slope difference. There are three types of data included in the test data set: single-layer, multi-layer, and interchanges between road systems. In addition to the elevation accuracy, surface continuity, slopes, and slope differences of the modeled roads are also analyzed.     

车辆主动悬架的非线性路面自适应控制研究

针对不同的路面状况,提出一种车辆主动悬架的非线性路面自适应控制方法。采用增加高低通非线性滤波器的方法,对以车身垂直加速度和悬架动行程为目标的控制函数进行优化处理,并利用多滑模鲁棒控制方法,设计了一种主动悬架的非线性路面自适应控制器。进行了零动力学子系统的稳定性分析及系统频率特性分析,理论分析表明整个系统是渐进稳定的。仿真结果显示,在不同的路面激励信号作用下,都能取得较好的控制效果,与被动悬架相比,大大改善了乘座的舒适性及车辆的操纵性能。     

川渝地区可控震源道路激振效果分析

川渝地区地形地貌复杂,可控震源在其乡村道路激振时存在激发信号畸变较大及激发能量耗散较大等问题。为了解决该问题,建立了可控震源道路激振模型,构建了可控震源道路激振效果评价体系,开展了川渝地区可控震源乡村道路激振效果研究,分析了可控震源道路激振能量耗散。结果表明：构建的激振效果评价体系能够较为全面地对川渝地区可控震源道路激振效果进行评价;相比碎石土路,可控震源在无缺陷水泥道路激振时传地能量减弱48.31%,地表接触中心点振幅下降77.44%,互作用力振幅下降18.18%,信号畸变增大34.69%,激振效果较差;道路缺陷对激振效果具有明显的减弱影响,圆形孔洞道路缺陷对激振效果的影响尤为突出,其中传地能量减弱54.94%,地表接触中心点振幅下降5.57%,互作用力振幅下降21.16%,信号畸变增大36.17%;川渝地区可控震源道路激振时,平板的结构能量耗散较大,约占系统总耗散能量的90%。研究结果可以为川渝地区可控震源乡村道路激振效果的改善提供理论指导。     

A New Approach for Road‐Vehicle Vibration Simulation

A new approach for road‐vehicle vibration simulation is proposed and demonstrated feasible by testing with three express‐road vehicle‐vibration records, that is, record A, two‐wheel electric bicycle, 80% loaded, traveling on urban road; record B, median van, 50% loaded, traveling on urban road; and record C, minivan, 80% loaded, traveling on urban road too. This method decomposes the original signal into a series of approximate Gaussian‐vibration segments and a shock segment with high kurtosis by moving crest factor and one‐tenth peak‐value method. Simulate Gaussian‐distribution vibration one by one from the power spectral density (PSD) of each decomposed segments. The overall signal is simulated by concatenating of each decomposed Gaussian segment. The simulated signal has not only the same overall root‐mean‐square (RMS), duration as the original signal, but also has a similar PSD to the original signal, without incurring excessive acceleration levels. This allows an improved and more representative simulated input signal to be generated that can be use in the current generation of vibration table.     

基于TWW函数的道路交通安全灰色评价方法研究

在研究国内外道路交通安全评价方法的基础上,根据我国道路交通安全现状及道路交通安全监督管理的要求,将灰色系统理论应用于道路交通安全评价,建立了一套基于TWW函数的道路交通安全灰色评价指标体系,并对6省市的交通安全水平进行了比较研究.     

Proposal for territorial distribution of the 2010 EU road safety target

European Union (EU) road safety policies include reduction in road fatalities by 50% during 2000–2010. The original territorial distribution of this target is uniform, as all the territories have to halve the number of fatalities regardless of their previous record.We propose a simple method of distributing the total effort required to reach the EU target of halving fatalities in a territory in such a way that those areas with a higher proportion of fatalities (relative to their populations) have the highest targets and the sum of all of the areas is the 50% reduction. The distribution function we use here is based on an inverse logarithmic function selected from among several alternative functions analyzed in an initial study. This use of weighted distribution functions has been applied since 2000 by the EU in other policies, such as the use of renewable energies.We applied the proposed distribution function to two territorial aggregation levels in the EUROSTAT Nomenclature of Territorial Units for Statistics (NUTS): NUTS0 for EU-15 and EU-25 Member States, and NUTS3 for the 50 Spanish provinces, comparing the new and old targets with the real achievements for the 2000–2006 period, and new and old targets for the 2000–2010 period.This is a simple proposal for modification of target distribution that can be further improved using other parameters, such as road or weather conditions.     

Mapping road surface features using single-camera images acquired by a mobile mapping system

Mapping road surface features, such as manholes, traffic markings, and cracks, is an essential task for transportation facility management. Although, these features can be rapidly surveyed using the latest mobile mapping techniques, a sophisticated sensor system with a complicated post-processing procedure is usually required. In this study, an efficient framework for modeling road surface features is proposed using a single camera system installed on a moving platform. First, the road surface images along a route of interest are acquired and potential objects are identified based on their shapes and recorded spectra in the images. Then, the contour pixels of the identified objects are extracted by the Canny edge detection technique. Finally, the 3D coordinates of the detected features in object space are obtained by integrating the profile-image technique and the instantaneous exterior orientation parameters of the platform. Based on the numerical results from a case study, it has been demonstrated that a fully automatic and reliable extraction of road surface features can be easily achieved by implementing the proposed approach. Consequently, the modeling of road surface features, which essentially contributes to the management of transportation facilities, can be executed in a cost-efficient manner.