U2000型不落轮镟床功能的拓展

广州地铁2号线赤沙车辆段采用德国Hegenscheidt-MFD公司生产的U2000型不落轮镟床进行电客车轮对的镟轮作业.为了能对不同踏面轮廓外形的工程车轮对进行镟修,需要对U2000型不落轮镟床进行功能拓展.以JX-3DT型接触网检修作业车的轮对镟修为例,从轮廓类型数据的描述、加工程序的编写及新轮对曲线的建立等方面,对U2000型不落轮镟床的功能拓展进行了详细介绍.用新编轮对曲线加工后的轮对踏面,经踏面廓形模板校验后,与模板之间非常吻合;机床测量值与实际结果也非常吻合.由此证明对U2000型不落轮镟床的功能拓展是成功的,为重点设备功能效益最大化提供了思路与实践.     

Partial-profilogram reconstruction method to measure the geometric parameters of wheels in dynamic condition

The present work poses a method for the measurement of geometric parameters of rail wheels in a dynamic condition, by reconstructing the profilogram from a portion of the wheel surface wear with artificial vision. The suggested procedure can work with a two-dimensional laser displacement transducer or by processing a sole image from a single camera with a structured light source. These two procedures require fewer devices and simpler implementation processes and allow the use of mathematical algorithms that demand less information processing, thus generating more accurate results. Railway operators may implement this method to perform predictive maintenance to their rolling stock at a fraction of the regular cost; thus achieving better precision, availability, maintenance performance and improving safety. Results were compared to those given by commercial equipment, showing similar precision but a better cost–benefit relation.     

Single wheel hub motor failures and their impact on vehicle and driver behaviour

This research work studies the impact of single wheel hub motor failures on the dynamic behaviour of electric vehicles and the corresponding driver reactions. An experimental study in a moving-base driving simulator is conducted to analyse the influence of single wheel hub motor failures for motorway speeds. Driver reaction times are derived from the measured data and discussed in their experimental context. The failure is rated objectively on the dynamic behaviour of the vehicle and compared to the subjective evaluation. Findings indicate that critical traffic situations impairing traffic safety can occur for motorway speeds. Clear counteractions by the drivers had to be taken.     

High-speed trains subject to abrupt braking

The dynamic response of high-speed train subject to braking is investigated using the moving element method. Possible sliding of wheels over the rails is accounted for. The train is modelled as a 15-DOF system comprising of a car body, two bogies and four wheels interconnected by spring-damping units. The rail is modelled as a Euler–Bernoulli beam resting on a two-parameter elastic damped foundation. The interaction between the moving train and track-foundation is accounted for through the normal and tangential wheel–rail contact forces. The effects of braking torque, wheel–rail contact condition, initial train speed and severity of railhead roughness on the dynamic response of the high-speed train are investigated. For a given initial train speed and track irregularity, the study revealed that there is an optimal braking torque that would result in the smallest braking distance with no occurrence of wheel sliding, representing a good compromise between train instability and safety.     

铁道车辆车轮和制动技术的发展趋势

介绍了欧洲对铁道车辆车轮和制动性能所进行的改进,探讨了美国货车ECP制动技术在欧洲运用的可能性。     

普通沥青及改性沥青混合料抗变形能力的对比分析

通过对普通沥青混合料和改性沥青混合料在不同温度、不同压力及不同试件厚度条件下所进行的车辙试验,对比分析了沥青类型对沥青混合料抗车辙能力所产生的不同影响,为工程中沥青的选择及混合料设计提供依据。     

基于模型预测控制的主动四轮转向车辆稳定性研究

为提高汽车在高速、低附着系数路面下的操纵稳定性,论文设计模型预测控制器跟踪线性二自由度理想模型,得到横摆角速度与质心侧偏角偏差,然后由二次规划算法计算实际的四个车轮转角,并在Carsim软件中建立开环角阶跃工况进行联合仿真。结果表明:文章所设计的基于模型预测控制的主动四轮转向汽车相对于前轮转向,能够有效降低整车角阶跃输入下的横摆角速度与质心侧偏角,更好地跟踪理想控制目标,主动四轮转向汽车提高了整车的操纵稳定性和路径跟随精度。     

摩托车镁合金车轮制造工艺和计算机辅助设计

随着镁合金材料的发展,铸造工艺的逐渐成熟,以及摩托车车轮对减振、轻量化的需求,摩托车镁合金车轮逐渐由实验阶段走向批量生产。镁合金与其它工程材料相比有很多优异的性能,其先进的制造工艺和计算机辅助设计开始应用到实际生产。     

线控转向系统转向盘力回馈控制模型的研究

根据轮胎和传统转向系的力学特性提出了利用车轮转角和车速计算得到转向盘回馈力的思路,并以此建立了线控转向系统转向盘回馈力控制模型,仿真和试验表明该模型能够满足路感要求。