机动车转向角校准方法

汽车转向角检测仪（以下简称“转角仪”）是用于测量汽车转向轮左、右两方向的最大转向角的仪器，它广泛应用于汽车制造厂和汽车综合检测站。过去检测转向角时。由于检测台面的不平整、圆心定位困难以及转向角指示不明显等原因。测量误差相当大，且因为没有稳定的操作平面，所以操作很不方便。汽车转向角检测仪还没有检定规程。且目前也没有行之有效的校准方法。为解决此难题。笔者通过收集资料、反复试验。摸索出了一套操作简便、读数清晰、系统误差小的对机动车转向角进行检测与校准的方法。该方法适用于计量技术机构和相关生产厂家。     

用经纬仪校准汽车车轮转向角检验台及测量不确定度的评定

根据国家标准GB／T17993—2005《汽车综合性能检测站能力的通用要求》规定,汽车车轮转向角检验台（以下简称“转角台”）是评价汽车综合性能检测站“转向操纵性检测能力”的主要设备之一。转角台用于检测“汽车转向轮的最大转角”,所以,转角台本身计量性能的准确性将直接影响到检测“汽车转向轮的最大转角”的正确性,因此必须对转角台进行定期的检定或校准,     

基于载荷识别的辅助变流器柜体振动模型修正

为提高某地铁车辆辅助变流器柜体振动响应模拟结果的精度,提出一种结合动载荷识别与优化算法的振动模型修正方法。首先在辅助变流器柜体有限元模型的基础上,计算出载荷与响应之间的传递函数,并利用振动响应测试数据和传递函数计算出施加在各测点的载荷谱。然后采用序列二次规划算法对有限元模型进行模型修正,通过构造目标函数将多输出模型修正问题转化为单输出模型修正问题。最后,对修正后的有限元模型进行振动响应求解,分析结果与振动测试数据比较验证了模型修正方法的正确性。该方法可为进一步实现辅助变流器柜体的减振降噪创造必要条件。     

浮动式汽车转向角测试台校准方法

浮动式汽车转向角测试台校准装置通过负荷加载单元的自重实现汽车转向角测试台的圆心定位及同轴调整,最大程度的还原实际测量状态下汽车转向角的角度参数测量,解决浮动式汽车转向角测试台现场校准圆心定位的技术瓶颈。     

对称圆弧加直线修正型线涡旋压缩机脱啮角与排气角研究

在采用对称圆弧加直线修正型线涡旋压缩机设计计算中,形成中心压缩腔时的转角与压缩机排气时主轴的转角完全不同.针对这两种情形下的主轴转角,由于没有完整而清晰的阐述,导致计算涡旋压缩机各压缩腔容积时容易产生较大误差.对此,通过研究采用对称圆弧加直线修正涡旋压缩机涡盘始端型线的几何特性,定义了脱啮角与实际排气角,阐明了二者之间相互区别,详细推导了脱啮角计算公式并分析了影响脱啮角的因素,且根据涡盘始端壁厚增加造成修正后中心压缩腔容积减少的本质特点,提供了修正后涡盘始端壁厚增加容积和实际排气角的计算方法.通过运算实例验证了脱啮角与实际排气角相差很大的结论,指出实际排气角将影响排气孔的设计.     

基于深度数据的空间人脸旋转角度估计

提出一种基于三维人脸深度数据的人脸姿态计算方法。利用人脸的深度数据以及与其一一对应的灰度图像,根据微分几何原理和相应的曲率算法与人脸数据中的灰度特征对人脸面部关键特征点定位,进而计算出人脸姿态在三维空间中的3个姿态角。实验证明该方法能在姿态变化情况下实现对人脸旋转角的准确估计,为进一步的人脸识别和表情分析提供基础。     

浅谈汽车前轮转向角的检测

随着中国汽车市场的成长,私家车的数量增加,行车安全性及舒适性要求也增高。汽车前轮的最大转向角是否符合汽车设计的正常范围是保证汽车安全行驶的重要参数之一,但是靠人工的方式准确测量出来却比较困难。本文介绍了汽车前轮转向角的检测原理及方法。     

Miner线性累计损伤理论在汽车试验场可靠性试验强化系数研究中的应用

 可靠性试验强化系数是汽车试验场制定规范的基础,运用科学的计算理论和方法可以得到准确的强化系数．根据Miner线性累积损伤理论,按照零件产生疲劳的因素对其进行修正,推导了计算汽车可靠性试验强化系数的数学模型,并在模型中引入损伤因子统计量和频率因子统计量的概念,使影响强化系数的多因素的物理意义更为准确．结合长安大学汽车试验场可靠性强化道路的实际,对某载货车在试验场上的载荷谱测试数据进行处理,计算得到试验场多种路面的综合强化系数．提供的理论和计算方法对其他试验场具有普遍的参考价值．     

机动车方向盘转向力-转向角检测仪角度量示值误差校准结果的不确定度评定

方向盘转向力-转向角检测仪（以下简称“检测仪”）是用来测量汽车、拖拉机和其他轮式车辆方向盘（转向盘）的操纵力及转动角度的仪器,其适用于方向盘的转角、转向力（或力矩）等静态或动态计量参数的检测,通常由机械构件、传感器、显示器等部分组成。转向力（或力矩）通过测力机构经传感器转换为电信号由仪表显示器显示的方法实现测量;     

基于中心流形理论的四轮转向汽车Hopf分岔分析

以四轮转向汽车(4WS)为研究对象,利用分析力学方法,建立了二自由度动力模型。利用Hurwitz代数判据,对4WS系统Hopf分岔进行了计算,得到分岔点。利用中心流形理论将高维4WS汽车系统降到二维,并通过计算二维分岔稳定性指标的正负判定原系统Hopf分岔的类型。利用Matlab软件对系统进行了仿真。结果表明,4WS汽车在一定的参数组合下出现转向自动摆动的性质,对振动的控制研究具有重要的参考价值。     

Precise identification of moving vehicular parameters based on improved glowworm swarm optimization algorithm

This paper proposes an indirect method for the identification of moving vehicular parameters using the dynamic responses of the vehicle. The moving vehicle is modelled as 2-DOF system with 5 parameters and 4-DOF system with 12 parameters, respectively. Finite element method is used to establish the equation of the coupled bridge–vehicle system. The dynamic responses of the system are calculated by Newmark direct integration method. The parameter identification problem is transformed into an optimization problem by minimizing errors between the calculated dynamic responses of the moving vehicle and those of the simulated measured responses. Glowworm swarm optimization algorithm (GSO) is used to solve the objective function of the optimization problem. A local search method is introduced into the movement phase of GSO to enhance the accuracy and convergence rate of the algorithm. Several test cases are carried out to verify the efficiency of the proposed method and the results show that the vehicular parameters can be identified precisely with the present method and it is not sensitive to artificial measurement noise.     

风洞射流和汽车绕流对声传播的影响

汽车风洞气动噪声测试中,由于射流和汽车绕流场的存在,流场外测量不能获取汽车声源的准确信息?研究以两种流场对声传播方向(声源漂移量)的影响开展?通过在风洞射流核心区安放特定声源和实车的试验,分别得到了射流和汽车绕流场对声传播的影响?研究表明两种流场对声传播都会产生较大影响,试验分析应加以考虑;研究分别对风洞射流和汽车绕流进行了气动数值仿真,据此拟合出剪切层和汽车绕流场速度分布线性化模型,并结合几何声学方法,建立了连续多层均匀运动介质声传播模型,得到了预测射流和汽车绕流产生声漂移量的方法?研究表明该方法可以有效预测风洞声学实验中介质运动对声传播方向的影响,并可用于风洞声学试验中流动对传播方向影响的修正?     

Microwave absorbers of two-layer composites laminate for wide oblique incidence angles

Advanced microwave absorbers for wide oblique incidence angles are required in many applications including wireless communication or vehicle identification in Intelligent Transport System (ITS) where 5.8 GHz Dedicated Short Range Communication (DSRC) system is applied. In this study, two-layer microwave absorbers are designed for the achievement of low reflection coefficient over wide incidence angles at 5.8 GHz. The absorbing layer of rubber composite containing magnetic iron flake particles and the surface layer of low dielectric constant (carbon black composite and glass fiber composite) have been used in the absorber design. On the basis of transmission line theory, the reflection loss has been calculated with variation of incident angles for both Transverse Electric (TE) and Transverse Magnetic (TM) polarization. At the optimum thickness of the composite layers, a low value of reflection loss (less than −10 dB) has been predicted for wide incidence angles up to 60° for both TE and TM polarization, which is well consistent with the reflected power measured by free-space arch test. The two-layer composite laminate consisted of magnetic absorbing layer with high magnetic and dielectric loss and surface impedance-matching layer of a controlled dielectric constant can be proposed for high potential microwave absorbers in ITS.     

基于带修正因子的模糊控制汽车主动悬架系统的研究

根据路面 -汽车系统的特点 ,提出一种在线可调整的模糊控制算法 ,其模糊控制规则表可以用解析的方法进行计算。该方法不仅体现了模糊控制算法对非线性系统具有的明显优势 ,而且利用 L MS自适应模块调整模糊控制器的修正因子 ,改善单一模糊控制算法对专家先期经验的依赖缺陷。针对简化的汽车模型 ,以汽车操纵稳定性及行驶平顺性为控制目标 ,进行了仿真计算及分析。又进一步在两自由度系统上进行了台架试验研究 ,结果证明该算法对系统的振动控制具有较好的效果。     

汽车碰撞护栏事故再现方法

为了应对大量的汽车碰撞护栏事故,提出了基于CRASH3碰撞模型的事故再现方法。该方法根据护栏的刚度特性,以车辆和护栏的残余变形量为输入,计算车辆的碰撞前速度,因此具有很强的可操作性。研究主要针对一款常见的高速公路波形梁护栏,通过对汽车冲击作用下的护栏进行有限元分析,研究了该款高速公路护栏的动力特征。研究发现在大多数情况下,随着变形量的增加,护栏受力几乎呈线性上升,基本符合CRASH3的线性假设。最后,应用上述方法,再现一起真实的汽车-护栏碰撞事故,将得到的碰撞前车速与PC-CRASH结果进行比较,初步证明了该方法的可行性。     

基于台架模拟检测汽车滑行性能的试验研究

通过台架模拟试验及滑行性能检测方法的分析,找出检测中存在的问题,并将道路与台架滑行试验进行比对,分析两者之间的差别。研究滑行距离与整车车轮阻滞力间存在的关联关系,提出了通过滚筒反力式制动检验台检验各车轮阻滞力,进而计算得到整车车轮阻滞力,并以整车车轮阻滞力占整车质量百分比评价汽车滑行性能的指标和方法。     

Map matching for intelligent speed adaptation

The availability of Global Navigation Satellite Systems (GNSS) enables sophisticated vehicle guidance and advisory systems such as Intelligent Speed Adaptation (ISA) systems. In ISA systems, it is essential to be able to position vehicles within a road network. Because digital road networks as well as GNSS positioning are often inaccurate, a technique known as map matching is needed that aims to use this inaccurate data for determining a vehicle?s real road-network position. Then, knowing this position, an ISA system can compare speed with the speed limit in effect and take measures against speeding. An on-line map-matching algorithm is presented with an extensive number of weighting parameters that allow better determination of a vehicle?s road network position. The algorithm uses certainty value to express its belief in the correctness of its results. The algorithm was designed and implemented to be used in the large scale ISA project `Spar pa? farten?. Using test data and data collected from project participants, the algorithm?s performance is evaluated. It is shown that the algorithm performs correctly 95% of the time and is capable of handling GNSS positioning errors in a conservative manner.     

自适应半主动悬架系统机械硬件在环试验研究

车辆处于加速、制动或转向工况时,运动惯性会导致车身发生俯仰、侧倾运动,如果幅值过大将使乘员产生紧张、眩晕等不舒适感。为解决此问题,提出一种基于车身姿态补偿控制与天棚加速度控制相结合的算法,建立自适应阻尼控制系统,不仅可使车辆垂向运动的振动效果得到改善,还能兼顾车身俯仰、侧倾控制,使其控制效果更加接近主动悬架。另外,搭建一种新型的减振器机械硬件在环试验台,可以对车辆垂向、俯仰及侧倾运动进行控制算法有效性验证,能克服四分之一减振器台架仅能验证车辆垂向运动的局限性。试验结果表明,与被动悬架相比,该算法在不同车速工况下B级路面和C级路面质心加速度幅值平均降幅达21.16%和13.21%,不同减速度和加速度工况下俯仰角波动峰峰值平均降幅达25.50%和28.82%,蛇形工况下不同车速的侧倾角幅值也均有降低。     

4WID-4WIS智能车阿克曼转向轨迹规划及位置估算

针对四轮独立驱动与四轮独立转向(four-wheel independent drive and four-wheel independent steering,4WID-4WIS)智能车的转向行驶工况,基于阿克曼转向原理,提出一种利用三阶贝塞尔曲线进行轨迹规划的新方法.首先,采用最优函数获取一条满足智能车初始状态约束...     

Combining virtual simulation and physical vehicle test data to optimize durability testing

This paper describes an ongoing project to model a vehicle on a computer with a multibody dynamics simulation software package and to merge that work with physical proving ground and laboratory tests in order to shorten vehicle development time. The intention is to mirror as closely as possible the behaviour of a physical vehicle in order to assist in determining its durability characteristics under varying road conditions. This modelling work is important because, if done with sufficient fidelity, it can be used in order to assess vehicle responses by using different suspension components or payloads. Also, potential issues associated with vehicle structure, suspension components or payload positioning can be observed on a computer prior to performing physical tests. The process has the potential to reduce vehicle development cost and time. The virtual dynamic vehicle model has been created by using Automatic dynamic analysis of mechanical systems (ADAMS) software package. The calculated outputs from the model are being compared to force and displacement data collected from actual vehicle on‐road testing or a servo‐hydraulic road test simulator (RTS). The virtual model can be adjusted until the calculated responses are in close agreement with those of the physical vehicle, thus linking the virtual and real‐world results.