Properties of roadway particles from interaction between the tire and road pavement

A large fraction of urban PM₁₀ concentrations is due to non-exhaust traffic emissions, including road dust, particles from tire/road interface, and brake lining particles. Although potential health and environmental impacts associated with tire wear debris have increased, few environmentally and biologically relevant studies of actual tire wear debris have been conducted. Tire wear particles (TWP) are released from the tire tread as a result of the interaction between the tire and the pavement. Roadway particles (RP), meanwhile, are particles on roads composed of a mixture of elements from tires, pavement, fuels, brakes, environmental dust, and the atmosphere. The main objective of the present study is to identify the contribution of tires to the generation of RP and to assess the potential environmental and health impacts of this contribution. First, a mobile measurement system was constructed and used to measure the RP on asphalt roads according to vehicle speed. The equipment of the mobile system provides PM₁₀ concentration by DustTrak DRX, and mass and number size distribution of fine and ultrafine particles by a fast mobility particle sizer (FMPS) and an aerosol particle sizer (APS). The dependence of RP mass and particle number concentration on vehicle speed was observed. It was also found that many particles were generated by rapid deceleration of the vehicle.     

基于车路系统的事故现场轮胎印迹强度参数化研究

为明确事故现场可视轮胎印迹强度与车辆动力学特性、轮胎橡胶磨损特征及道路表面灰度之间的关联特性,提出基于车路耦合的事故现场轮胎印迹强度参数化研究方法。通过结合动态滑动摩擦因数模型及轮胎非线性模型,建立车辆路面9 DOF非线性系统动力学模型,运用VBOX惯性测量技术验证模型的有效性。运用胎面磨损能量模型,从车路系统角度确定车辆、轮胎和路面特性对轮胎全局摩擦力及胎面磨损特性的影响。结合印迹强度特征模型提出轮胎印迹强度参数研究方法,选取不同制动、转向角工况及3组路面、胎面特性对轮胎路面接地力学特性、胎面橡胶磨损量、可视轮胎印迹特征进行仿真分析。结果表明：印迹强度仅与全局摩擦力大小有关,与轮胎路面滑移方向无关;滑移工况下胎面橡胶磨损量随着全局摩擦力和滑移速度的增大而增大,而印迹强度变化不明显;制动力矩和道路表面灰度对产生可视轮胎印迹起决定作用,转向角主要影响不规则可视轮胎印迹的产生;前轮轮胎最先出现可视印迹,且可视印迹长度和强度均高于后轮轮胎;采取可视印迹起点作为事故车辆速度判定具有一定的误差,应根据具体情况进行具体分析;研究成果能够为基于可视轮胎印迹的交通事故重建提供理论基础。     

基于图像识别轮胎变形的非接触式车辆称重方法

为了解决接触式车辆称重方法存在的安装和维修成本高、使用年限短、识别精度低等问题,创新性地提出一种基于计算机视觉获取轮胎变形的非接触式车重识别方法。首先,利用视频图像采集装置拍摄车辆轮胎图像信息,通过图像处理技术提取轮胎轮廓,并根据轮廓变形计算轮胎的垂向挠度。其次,通过胎压监测系统(TPMS)获取轮胎的真实胎压值,对于没有安装TPMS的车辆,则可以通过图像字符识别技术读取轮胎侧壁的胎压标识信息,再利用统计回归方式确定实际胎压值。在此基础上,将轮胎垂向挠度和胎压值代入推导的称重公式计算轮胎承受的重量,再将所有轮胎承受重量求和得到车辆总重量。最后,以现场的乘用车和重载货车为例,验证在不同胎压和重量变化下非接触式车辆称重方法的准确性,并对比分析3个称重公式的准确性。研究结果表明:车重识别准确率随着胎压增大而降低,随着车重增大而上升;轮胎刚度拟合公式的载重识别准确率达到95%以上,高于理论推导公式和半经验拟合公式。提出的非接触式车辆称重方法具有测量范围广、无需任何额外传感设备、不用封闭交通和易于信息集成等优势,有效地突破了现有接触式车重识别技术的瓶颈,具有很好的工程应用前景。     

基于自适应模型预测的智能汽车横向轨迹跟踪控制

当路面附着情况和车辆行驶状态不断变化时,基于恒定侧偏刚度的模型预测控制(MPC)不能考虑轮胎非线性特性的影响,难以保证车辆轨迹跟踪的适应性。为此,提出一种考虑轮胎侧向力计算误差的自适应模型预测控制(AMPC),以提高智能汽车在不确定工况下的轨迹跟踪性能。分析了路面附着系数和垂向载荷对轮胎侧向力的影响,基于平方根容积卡尔曼滤波(SCKF)算法,设计了利用侧向加速度和横摆角速度作为测量变量的前后轮胎侧向力估计器。利用轮胎侧向力线性计算值与估计值的差值计算得到侧偏刚度修正因子,设计了前后轮胎侧偏刚度的自适应修正准则,进而提出了一种基于时变修正刚度的AMPC控制方法。基于CarSim与MATLAB/Simulink联合仿真和硬件在环测试平台,对AMPC控制的有效性和实时性进行了验证。研究结果表明：在不同的路面附着情况和车辆行驶状态下,AMPC控制都能够降低横向位置偏差和航向角偏差,有效提高车辆的轨迹跟踪精度,其控制效果明显优于基于恒定侧偏刚度的标准MPC控制。尤其在低附着工况下,标准MPC控制会因为线性轮胎力的计算误差过大而导致车辆在轨迹跟踪时严重失稳,而AMPC控制通过估计轮胎力修正侧偏刚度依然能够保证车辆稳定有效的跟踪参考轨迹。所提出的AMPC控制在保证控制精度的同时具有良好的实时性,对智能汽车控制系统的设计与优化具有重要参考价值。     

Sideslip angle estimation based on input–output linearisation with tire–road friction adaptation

An adaptive sideslip angle observer considering tire–road friction adaptation is proposed in this paper. The single-track vehicle model with nonlinear tire characteristics is adopted. The tire parameters can be easily obtained through road test data without using special test rigs. Afterwards, this model is reconstructed and a high-gain observer (HGO) based on input–output linearisation is derived. The observer stability is analysed. Experimental results have confirmed that the HGO has a better computational efficiency with the same accuracy when compared with the extended Kalman filter and the Luenberger observer. Finally, a road friction adaptive algorithm based on vehicle lateral dynamics is proposed and validated through driving simulator data. As long as the tires work in the nonlinear region, the maximal friction coefficient could be estimated. This algorithm has excellent portability and is also suitable for other observers.     

爆胎汽车整车运动分析及控制

通过轮胎试验得到GT175/60 R14轮胎在正常胎压及零胎压下的力学特性参数,以此为依据,运用CarS im软件对爆胎汽车进行整车动力学仿真,找出汽车偏航原因,分析驾驶员不同操作所引起的整车运动性能变化以及汽车稳定性控制系统对爆胎汽车的影响。仿真结果表明,稳定性控制系统对于减轻爆胎带来的后果具有积极的作用。     

Scaled vehicle tire characteristics: dimensionless analysis

This article demonstrates the use of dimensional analysis for scaled vehicle tires. The motivation for this approach is the understanding of realistic nonlinear tire behavior in scaled vehicle control studies. By examining the behavior of vehicle tires within a dimensionless framework, several key tire parameters are developed that allow for an appropriate relationship between full-sized tires and scaled tires. Introducing these scalings into vehicle dynamics studies allows for the development of scaled vehicles that have a high degree of dynamic similitude with full-sized vehicles, but are safer and more economical testbeds on which to develop experimental control strategies. Experimental data are used to compare the nonlinear characteristics for sets of scaled and full-sized tires. Finally, design of a scaled vehicle based on tire characteristics is demonstrated.     

A Versatile Flat Track Tire Testing Machine

Summary A flat track tire testing machine developed by the IMMa group is described. It permits the simulation and study of the dynamic behavior of a great variety of tires under controllable and repetitive highly dynamic realistic working conditions in the laboratory for a diversity of vehicles, from motorcycles to light trucks. The machine incorporates: – a hydraulically operated tire support and loading system with wide operating ranges; – a computer controlled brake system to simulate braking maneuvers with ABS systems; – a complete sensorial system; – a data acquisition and control system continually monitoring and acting on the experimental variables, i.e., tire and belt speed, longitudinal slip, slip and camber angles, tire pressure, tire normal force, etc. As an application example, results are presented that adjust the parameter of the magic formula for a standard 175/70 R14 passenger vehicle tire. Accurate mathematical tire models are recognized as essential for the prediction of vehicle dynamic performances using simulation tools.     

A Versatile Flat Track Tire Testing Machine

Summary A flat track tire testing machine developed by the IMMa group is described. It permits the simulation and study of the dynamic behavior of a great variety of tires under controllable and repetitive highly dynamic realistic working conditions in the laboratory for a diversity of vehicles, from motorcycles to light trucks. The machine incorporates: - a hydraulically operated tire support and loading system with wide operating ranges; - a computer controlled brake system to simulate braking maneuvers with ABS systems; - a complete sensorial system; - a data acquisition and control system continually monitoring and acting on the experimental variables, i.e., tire and belt speed, longitudinal slip, slip and camber angles, tire pressure, tire normal force, etc. As an application example, results are presented that adjust the parameter of the magic formula for a standard 175/70 R14 passenger vehicle tire. Accurate mathematical tire models are recognized as essential for the prediction of vehicle dynamic performances using simulation tools.     

用于不平路面车辆动力学仿真的轮胎模型综述

介绍了轮胎在不平路面的动力学特性。在回顾不平路面轮胎动力学模型发展的基础上，以近期的研究工作为重点，对用于不平路面车辆动力学仿真的轮胎模型进行了较为系统的介绍。概要地阐述了各种轮胎模型的建模理论、方法，并进行了分析和评述。最后，总结了不平路面轮胎力学建模的核心问题及发展方向，对不平路面车辆动力学仿真选择合适的轮胎模型给出了建议。     

浅谈中央充放气系统充放时间计算

本文针对不同容积轮胎及充气压力下充放气系统所需充放时间进行计算,使其根据气温,路面状况的不同,自动调节控制轮胎气压,产生最大附着力而又不至于产生过大阻力,保证汽车始终保持最合理的运动状态,提高车辆的地面通过性和工作效率。     

基于径向刚度法的车辆翻新轮胎使用寿命判定

为了有效判定车辆翻新轮胎的剩余使用寿命，需要科学确定废旧轮胎胎体橡胶老化程度对翻新轮胎使用寿命的影响。在分析废旧轮胎胎体橡胶老化规律的基础上，通过橡胶老化试验测试及回归分析，确定了胎体弹性模量随着橡胶老化年限增加近似线性增大的影响规律；结合计算机仿真技术及试验测试技术，基于轮胎径向刚度法提出了翻新轮胎剩余使用寿命不安全系数计算方法，其计算数值大小与翻新轮胎径向刚度和新轮胎径向刚度之差成正比，与新轮胎径向刚度值成反比；构建了由橡胶加速老化系统、弹性模量测取系统、承载-变形计算机模拟系统和承载-变形测试系统等组成的翻新轮胎剩余使用寿命判定系统；基于径向刚度法和判定系统提出了车辆翻新轮胎剩余使用寿命判定规则，确定了翻新轮胎胎体剩余使用寿命判定具体流程；根据剩余使用寿命不安全系数计算方法和判定规则，将翻新轮胎确定为可正常使用、需降速使用和需报废处理3个级别，并利用11.00R22.5载重车辆翻新轮胎进行了剩余使用寿命判定与评价，依据判定规则分别计算了不同使用年限3条翻新轮胎的剩余使用寿命不安全系数，确定出3条翻新轮胎所对应的级别，判定与评价结论与实际使用情况相吻合。研究结果表明：废旧轮胎胎体橡胶老化程度对翻新轮胎剩余使用寿命影响显著，翻新轮胎径向刚度与剩余使用寿命之间存在较大影响关系；废旧轮胎胎体橡胶老化程度越严重和径向刚度越大，翻新轮胎的剩余使用寿命将会越短。     

基于虚拟路面的整车路噪轮胎参数相关性研究

为了在设计阶段保证整车的NVH性能,通过搭建虚拟路面仿真平台探究轮胎关键物理参数对于整车路面振动噪声的影响规律。结合实车采集的试验场NVH路面PSD、高精度物理轮胎CDTire模型以及整车声固耦合模型,建立完整的整车路噪仿真环境。通过某款SUV的仿真结果表明,不同款轮胎及同款轮胎不同批次对整车路面振动噪声有直接的影响。虚拟路面方法可以在整车开发早期甄别出在车辆噪声中起主导作用的频率段,从而排查明显的NVH设计缺陷,同时,可以为车型NVH正向开发提供轮胎选型依据。     

A study on the mechanism of tire/road noise

This paper describes the mechanism of generating tire/road noise, which contributes very much to the vehicle exterior noise, by dividing the factors of the tire/road noise into exciting force, vibration characteristics and acoustic radiation characteristics. In addition, it shows the effectiveness of suppressing the distinctive tread vibration mode, which is the main mode of vibration radiating noise of around 1 kHz with a high sound pressure level in radial tires for passenger cars.     

浅谈汽车轮胎磨损谈及有效保养

汽车轮胎每天都要和粗糙的路面接触,发生磨损自然是在所难免的事情。但是,绝不能因此就对轮胎的磨损掉以轻心,因为可以从轮胎的磨损程度发现汽车隐藏的故障。一般来说,如果汽车没有问题,轮胎的磨损就应该是均匀的;如果磨损不均,那可能就是有问题了。在汽车的行驶过程中,如果操作使用不当或维护保养不及时,将导致轮胎的异常损伤,直接影响汽车的动力性、经济性和各种使用性能的发挥,甚至造成严重的行车事故。汽车轮胎不仅影响整车动力性、经济性和轮胎使用寿命,而且直接影响汽车的操纵稳定性、汽车行驶方向的可控性,关系到人的生命和财产安全。因此,要科学地按技术要求控制轮胎气压,减少或避免轮胎异常磨损,合理维护和正确使用轮胎。     

载货汽车轮胎对车外加速噪声判定准则的影响

汽车加速行驶车外噪声是多个声源综合的结果,其中轮胎噪声是重要的噪声源之一。根据国家车辆公告规定,车辆在选配不同的轮胎时,应分别进行车外加速噪声的试验。载货汽车轮胎对车外加速噪声的影响可通过将大量载货汽车的加速行驶车外噪声试验及滑行车外噪声试验的结果带入理论公式计算确定。同时通过对不同轮胎轮的比较,进一步说明轮胎对车外加速噪声的影响,为以后标准的制订提供依据。     

客车轮胎建模和对侧倾稳定性的影响研究

客车轮胎与客车整车的侧倾稳定性有密切联系,ADAMS是典型的动力学虚拟样机仿真软件。介绍了在ADAMS中建立非线性轮胎的方法,在ADAMS中建立客车整车模型,通过改变整车模型中轮胎的刚度和阻尼,研究客车轮胎对整车侧倾稳定性的影响,从而为设计出符合性能要求的客车轮胎提供一定的理论依据。     

轻型货车轮胎接地压力分布实测

利用自主开发的轮胎接地压力测试仪,进行了轻型货车不同花纹和不同使用年限轮胎,在不同轮胎胎压和不同负荷作用下,轮胎的接地压力分布规律测量。实测结果发现:轻型货车轮胎与路面的接触形状更接近于矩形;新胎比旧胎的接地压力要均匀些;轮胎胎压与平均接地压力、轮胎负荷与平均接地压力、轮胎负荷与有效接地面积基本上呈线性关系。     

Development of twin-chamber on-wheel resonator for tire cavity noise

Tire cavity noise is a noise which produces reverberations. Given the ringing in the ears that it causes vehicle occupants, it has long been one of the main road noise issues. For the countermeasure against tire cavity noise, since drastic solution is still more difficult for the downstream measure against a body system with the increase of big weight, its device in the tire cavity of the countermeasure against the origin is the most effective for a light weight and drastic solution. Some reduction devices of tire cavity noise have come to be commercialized in recent years. As a commercialization example, what equipped the tire inside surface with the noise absorbing material, and the thing which equipped roadwheel with the resonator are developed. However, application of these devices is limited to some of tires and high-class vehicle types from cost restrictions, and at present, it does not result in technical generalization and has not diffused through it so much. Since the new structure which reduces weight and cost by 50 % or more was suggested towards generalization of the Helmholtz resonator technology which is a flexible device which can equip roadwheel and does not limit a tire brand and commercial production was realized, this paper introduces that theoretical background and realization structure. And this device has been successfully applied to mass-production models on the market.     

基于“移动水坝”的高速公路雨天行车安全性研究

为了减少雨天交通安全隐患,保障高速公路行车安全,根据雨天高速公路实际行车状态、路面径流特点和车辆水膜相互作用探究雨天安全行车速度。首先,提出“移动水坝”概念,并分析“移动水坝”现象出现的原因和形成机理;依据水力学基本理论探究“移动水坝”现象中水膜厚度和车辆滑水限速值的变化规律;然后,利用Fluent软件仿真车辆对水流的阻挡作用,依据外侧车道大车行车间距的水压力探究连续“移动水坝”形成的条件,并确定外侧车道大车在不同行驶速度下相应的临界车头时距;最后,应用流体力学原理仿真分析车辆行驶速度和水膜厚度与轮胎受到的动水压力之间的关系,确定不同降雨强度下内侧车道小客车的滑水限速值。研究结果表明：雨天在高速公路外侧车道行驶的大车会对路面径流产生阻挡作用,出现“移动水坝”现象;“移动水坝”作用下水膜厚度较正常排水状态下增加,导致内侧车道行驶的小客车滑水限速值降低;设定试验条件下外侧车道大车间距40 m时,两车的水坝作用连续,增加大车车头时距可以减弱连续“移动水坝”作用;车辆行驶过程中轮胎受到的动水压力随水膜厚度及行驶速度的增加而增大,小客车在“移动水坝”作用下发生滑水的概率增加,根据轮胎动水压力值和滑水值确定不同降雨强度对应的临界滑水速度,可相应作为雨天高速公路小客车行驶速度限值。