某新型车铝合金车轮结构优化与设计研究

为提高车轮设计质量,应用有限元方法,根据国家标准,对某型车铝合金车轮进行疲劳寿命分析,并结合试验设计、近似建模技术及基于蒙特卡罗模拟技术的6σ可靠性优化设计理念,从提高车轮寿命、减轻重量角度进行车轮优化设计。结果表明,轮辐上开孔能够有效引导车轮受载情况下的应力分布,改善疲劳载荷的循环特性,从而有效地提高车轮疲劳寿命。通过对车轮进行确定性优化和基于6σ的可靠性优化的对比,分析了设计变量波动对产品设计质量的影响,结果表明,可靠性优化明显优于确定性优化,具有较高的工程实用价值。     

买农用三轮车免征车辆购置税

为促进农业生产发展．切实减轻农民负担．财政部、国家税务总局经国务院批准，自2004年10月1日起对农用三轮车免征车辆购置税。农用三轮车是指：柴油发动机，功率不大于7．4千瓦．载重量不大于500公斤．最高车速不大于每小时40公里的三个车轮的机动车。     

成都市电动自行车发展导向与交通管制策略设计——城市绿道系统

1背景介绍成都地区机动车保有量约为300万辆,但电动自行车却有500万辆,环保、轻便的电瓶车备受市民喜爱的同时,也有自己的尴尬:一旦重量和速度超标,都会被纳入机动车管理,瞬间成为不符合标准的产品,同时电动自行车的管理也成为了     

机动车视频标注规范研究与标注平台的实现

针对智能交通系统(ITS)涉及到的机动车视频处理技术，提出了一种新颖的城市机动车视频标注规范，并开发了一个城市机动车视频标注平台。该平台可辅助用户对机动车视频进行手工标注。在视频处理算法的测试和训练中，利用标注好的机动车视频样本，能够为算法的训练、测试、改进、优化等提供极大的帮助。     

超载莫通行—超载检测系统设计

正机动车超载一直是让人头疼的问题,有些司机和车主受利益驱动,"多拉快跑",不仅经常造成交通事故,而且对公路造成严重破坏。据分析车辆超限重量增加和其对路面的损害是呈几何数增长的,超载10%的货车对道路的损坏会增加40%,一辆超限2倍的车辆行使一次,对公路的损害相当于不超限车辆行使16次,所以,必须治理超载。本文介绍的这种机动车超载检测系统,可以安装在高速公路口和收费路口,限制超载车辆通行。     

一种车轮轮廓的自动提取方法

提取车轮轮廓是交通事故现场处理系统中的一个关键问题, 其精度将直接影响现场测量的精度和勘查质量. 本文提出了一种鲁棒地提取车轮轮廓的方法. 由于提取钢圈轮廓比提取车轮橡胶轮廓容易, 而且钢圈轮廓和车轮轮廓可以近似看作同一平面上的两个同心圆, 所以在本文中, 我们首先提取钢圈轮廓、钢圈圆心 (即车轮圆心) 和车轮与地面接触点在图像上的投影, 然后利用射影变换保持交比不变的性质求出车轮轮廓. 大量不同天气下图像的实验结果验证了该方法的有效性.     

城市交通节能减排策略的动态仿真

针对日益严峻的城市交通拥堵、机动车尾气污染和交通能耗问题，运用系统动力学和新陈代谢预测的方法构建了城市交通节能减排管理模型；对模型中的不同治理手段进行仿真分析，研究其对交通缓堵、减排和节能的影响。分析结果表明：经济手段可以显著地缓解交通拥堵、减少空气污染，但对降低交通能耗作用不大。行政手段对私家车出行具有双重作用，短期效果显著，长期会导致拥堵加剧、交通能耗反弹等负面效应。比起单一的经济手段和行政手段，大力发展公共交通，是缓解交通拥堵和减少空气污染更有效的途径。利用技术手段提高机动车节能减排水平，可以有效地减少机动车尾气排放和能源消耗；结合分析结果，制定相应的提升策略。     

基于ARM耗油测量仪的设计

耗油性能测量仪,用于小型机动车比如摩托车出厂时耗油性能的测试.通过上位机软件执行"开阀"操作,往杯子里加油,加到一定程度(不溢出),通过软件读出油的重量,软件执行"关阀"操作,并读出此时油的重量.用杯子里的油作为燃料,通过现场运行摩托车耗油,由ARM控制USB数据传输,通过软件读取油消耗量,来标定这辆摩托车的耗油性能.     

四轮移动机器人的前后轮双里程仪系统的误差分析

四轮移动机器人的驾驶和驱动系统的左右轮分别装上里程仪，里程仪的读数反映了车轮转过的角度和转向，在车轮直径固定的情况下，便可计算出车轮的移动距离．根据左右车轮的记数值，可以计算出车体的位置和方位．本文对前后轮双里程仪系统进行了对比分析，在相同的误差下，驱动轮双里程仪系统优于前轮驾驶角和双里程仪器系统，这对实际工作有指导作用．     

基于滑转率的六轮纵列式月球车驱动控制研究

基于车轮滑转率和车轮地面力学,研究了月球车在松软月面行驶时的车轮过度下陷问题.将 月球车车轮下陷和车轮—土壤作用力表达为车轮滑转率的函数,结合车辆地面力学理论并考 虑纵列式车轮多通过性土壤参数的修正,建立了月球车的动力学模型.判断车轮是否发生过 度下陷的标准为土壤所提供给驱动轮的土壤推力能否克服土壤对车轮的阻力.利用建立的动 力学模型,计算出能够保证车轮不会过度下陷的期望滑转率.考虑到月球车动力学系统的非 线性和不确定性,设计了以车轮滑转率为状态变量的滑模驱动控制器.仿真结果表明,采用 该控制器可以较快地跟踪期望滑转率,避免车轮的过度滑转下陷,保证月球车能够在软质路 面上正常行驶.     

Effect of tangent track buckle on vehicle derailment

In order to investigate the effect of a tangent track buckle on the dynamic derailment of a railway vehicle, a coupled vehicle/track dynamics model is developed, in which the vehicle is modeled as a 35 D.O.F. multibody system and the track is modeled as a 3-layer discrete elastic support model. Rails are assumed to be Timoshenko beams supported by discrete sleepers, and the effects of vertical and lateral motions and rolling of the rail on the wheel/rail creepages are taken into account. The sleepers are treated as Euler beams on elastic foundation for the vertical vibration, while as lumped masses in the lateral direction. A moving sleeper support model is developed to simulate the effect of the periodical discrete sleepers on the vehicle/track interaction. The vehicle and the track are coupled by wheel/rail contacts whereas the normal forces and the creep forces are calculated using the Hertzian contact theory and the nonlinear creep theory by Shen et al., respectively. The equations of motion of the coupled vehicle/track system are solved by means of an explicit integration method. A tangent track buckle is simulated with a cosine function, which describes the misalignment of the track with different lengths due to its buckling. In the analysis the effects of the buckle wavelength and amplitude and of the vehicle speed on the dynamic behavior of the coupled vehicle/track system are considered. The present paper analyzes in detail the conventional derailment coefficients which include the ratio of the wheel/rail lateral force to the vertical force, the wheel load reduction, and the new criteria indicating the wheel/rail contact point traces and the wheel rise with respect to the rail. These criteria are simultaneously used to evaluate the risk of derailment of the whole vehicle. The numerical results obtained indicate that the track misalignment caused by the buckle and the vehicle speed have a great influence on the whole vehicle running safety when the vehicle passes through the buckled tangent track.     

Estimation of moving vehicle locations using wheel shape information in single 2-D lateral vehicle images by 3-D computer vision techniques

An approach to the estimation of moving lateral vehicle locations for driving assistance using wheel shape information in single 2-D vehicle images by 3-D computer vision techniques is proposed. The location scheme is supposed to be performed on a vehicle with a camera mounted on the front bumper. An analytical solution is applied to estimate locations of the lateral vehicle. Firstly, the rear wheel shape of a lateral vehicle moving in a nearby lane is imaged. By using the Hough transform, the projected wheel shape, which is an ellipse, is detected. Secondly, the equation of the detected ellipse is used to infer the orientation angle of the lateral vehicle with respect to the camera view direction. Finally, the center of the ellipse shape is used to determine the relative position of the lateral vehicle with respect to the camera lens center. Moreover, an edge-point verification algorithm is utilized to extract the ellipse shape more precisely in the image processing stage. Both computer simulated and real images are tested and good experimental results show the effectiveness of the proposed approach for estimating lateral vehicle locations. The results are useful for driving assistance and vehicle collision avoidance and are discussed in detail.     

一种小型轮式平台的设计与运动仿真

针对传统轮式车辆转向半径大,转向阻力大的问题,提出一种新型的轮式车辆平台方案。该平台的运动机构由定轴转动的前轮和万向轮后轮组成,主动轮是由轮毂电机独立驱动的前轮,后轮为从动轮;平台采用电驱动,包含电源系统,控制系统,车体等几大部分,相比于传统的车辆,该平台引进了万向轮,大大加强了平台的灵活性,转向更加方便;通过在Solid Works中建立模型,然后在RecurDyn中进行仿真,设置不同的实验条件,根据实验结果可以得到:当后轮为万向轮时,平台相对于后轮固定具有较好的转弯能力,横摆角速度减小,平台转弯更加平稳;同时,平台具有一定的越障能力,可以在一定的复杂地形上完成运动,能够跨越一定尺寸的壕沟。这一结果可以为科学研究和实际应用提供理论依据。     

基于小波变换的车辆动态轴重信号消噪

对车辆的运动状态和动态轴重信号干扰的产生进行分析,在此基础上对车辆动态轴重信号的噪声在小波变换下的特性进行了说明,据此提出一种可有效消除车辆动态轴重信号噪声的软阈值选取方法;通过具体仿真实例说明该阈值处理方法的优点,表明基于该方法对车辆动态轴重信号消噪是很有效的。     

基于AKF和RLS的车辆簧载质量辨识研究

实际应用中,车辆负载会随着乘客和货物的变化而发生显著改变.提出结合自适应卡尔曼滤波器(AKF)与递推最小二乘算法(RLS)进行车辆簧载质量的在线辨识.首先,采集四分之一车辆悬架的簧载振动加速度、动行程及车轮垂向加速度信号,对车辆悬架系统中的簧载质量和车轮的绝对速度进行估计,进而由遗忘因子递推最小二乘算法辨识车辆簧载质量.分析了在不同路面等级下,卡尔曼滤波器的过程噪声协方差和测量噪声协方差对悬架状态估计精度的影响.仿真结果显示,在选取与车辆行驶路面等级匹配的过程噪声协方差和测量噪声协方差时,车辆悬架状态参数的估计精度较高,并能够在线准确地辨识得到车辆的簧载质量值.     

Improving Point Cloud Accuracy Obtained from a Moving Platform for Consistent Pile Attack Pose Estimation

We present a perception system for enabling automated loading with waist-articulated wheel loaders. To enable autonomous loading of piled materials, using either above-ground wheel loaders or underground load-haul-dump vehicles, 3D data of the pile shape is needed. However, using common 3D scanners, the scan data is distorted while the wheel loader is moving towards the pile. Existing methods that make use of 3D scan data (for autonomous loading as well as tasks such as mapping, localisation, and object detection) typically assume that each 3D scan is accurate. For autonomous robots moving over rough terrain, it is often the case that the vehicle moves a substantial amount during the acquisition of one 3D scan, in which case the scan data will be distorted. We present a study of auto-loading methods, and how to locate piles in real-world scenarios with nontrivial ground geometry. We have compared how consistently each method performs for live scans acquired in motion, and also how the methods perform with different view points and scan configurations. The system described in this paper uses a novel method for improving the quality of distorted 3D scans made from a vehicle moving over uneven terrain. The proposed method for improving scan quality is capable of increasing the accuracy of point clouds without assuming any specific features of the environment (such as planar walls), without resorting to a “stop-scan-go” approach, and without relying on specialised and expensive hardware. Each new 3D scan is registered to the preceding using the normal-distributions transform (NDT). After each registration, a mini-loop closure is performed with a local, per-scan, graph-based SLAM method. To verify the impact of the quality improvement, we present data that shows how auto-loading methods benefit from the corrected scans. The presented methods are validated on data from an autonomous wheel loader, as well as with simulated data. The proposed scan-correction method increases the accuracy of both the vehicle trajectory and the point cloud. We also show that it increases the reliability of pile-shape measures used to plan an efficient attack pose when performing autonomous loading.     

基于动力学模型的汽车制动稳定性虚拟展示

现有3D引擎的物理模型不能真实反映车辆制动时的运动状态。为此,提出一种汽车制动稳定性虚拟展示系统。建立汽车动力学模型,包括四轮车辆模型和车轮轮胎模型,利用上层仿真软件对动力学模型进行运算和虚拟场景渲染,给出车轮状态和虚拟仪表的展现方法,并基于3D引擎设计虚拟展现系统。实验结果表明,该系统能同时观测整车及车轮的运行状态,实时再现制动过程中车轮抱死、车身横摆侧滑的行为,其动力学模型能够满足虚拟展现对画面渲染的实时性、连续性要求。     

微型多功能车双横臂独立悬架优化设计

微型多功能车双横臂前独立悬架设计的好坏对车轮跳动时前轮前束和轮距的变化有很大的影响.运用虚拟样机技术,在ADAMS环境下建立了微型多功能车SX2526的前双横臂独立悬架刚-柔耦合模型,进行了运动学仿真.在此基础上运用"主要目标法"进行了以前轮前束和轮距变化为目标的悬架多目标优化设计,得到优化后的悬架空间结构的几何形式.经过悬架优化设计,前轮前束和轮距随车轮跳动时的变化范围大大减小.极大地改善了微型多功能车行驶过程中的操作稳定性.     

空气弹簧在100%低地板轻轨车上应用可行性分析*

基于多体动力学仿真软件SIMPACK,对某型采用纵向耦合边驱电机转向架的100%低地板轻轨车三模块编组建模,在MATLAB/Simulink中对其中央悬挂部件空气弹簧的主气室、节流孔、附加气室建模.对100%低地板轻轨车运行工况进行设定,通过联合仿真的方式对空气弹簧在100%低地板轻轨车上应用可行性进行分析,得到:1)空气弹簧应用到100%低地板车上后,车辆蛇行失稳临界速度为149km/h,大于设计时速,车辆有较好的运行稳定性.2)车辆运行时,平稳性及最大加速度指标均小于2.5,车辆有较好的运行平稳性.3)车辆通过小半径曲线时,轮重减载率、脱轨系数、轮轴横向力、轮轨横向力指标均小于评判标准限值,车辆有较好的曲线通过能力.4)空气弹簧在通过工况设定的小半径曲线时,各项性能指标均符合该型空气弹簧技术标准,空气弹簧在100%低地板轻轨车上应用可行.     

基于Adams/Car的汽车前悬架仿真分析及优化设计

针对某车型的麦弗逊前悬架系统,用车辆多体动力学仿真软件Adams/Car建立该悬架的虚拟样机模型,对其进行双轮同向跳动激振仿真分析,并综合评价该悬架的车轮定位参数、主销后倾拖距和转向角随轮跳的响应特性.在仿真分析的基础上,针对不合理的结构设计参数,利用Adams/Insight模块进行基于设计变量灵敏度分析的优化设计.优化后的悬架参数能很好地满足设计要求,从而达到提高该悬架系统整体性能的目的.