An integrated control strategy for the composite braking system of an electric vehicle with independently driven axles

For an electric vehicle with independently driven axles, an integrated braking control strategy was proposed to coordinate the regenerative braking and the hydraulic braking. The integrated strategy includes three modes, namely the hybrid composite mode, the parallel composite mode and the pure hydraulic mode. For the hybrid composite mode and the parallel composite mode, the coefficients of distributing the braking force between the hydraulic braking and the two motors' regenerative braking were optimised offline, and the response surfaces related to the driving state parameters were established. Meanwhile, the six-sigma method was applied to deal with the uncertainty problems for reliability. Additionally, the pure hydraulic mode is activated to ensure the braking safety and stability when the predictive failure of the response surfaces occurs. Experimental results under given braking conditions showed that the braking requirements could be well met with high braking stability and energy regeneration rate, and the reliability of the braking strategy was guaranteed on general braking conditions.     

蒸汽动力装置回汽制动工况下倒车级动叶安全性分析

针对蒸汽动力船舶回汽制动工况下倒车汽轮机叶片的运行安全性问题,通过回汽制动工况下倒车汽轮机的变工况工作过程分析,建立回汽制动工况下倒车级动叶的弯曲应力模型,并基于Matlab-Simulink环境,建立倒车级动叶的弯曲应力的仿真模型.仿真结果表明,回汽制动工况下,采用理想制动策略时倒车级第二级动叶的弯曲应力会超过安全许用值,导致倒车汽轮机的损坏,影响蒸汽动力装置的安全运行,因此需对倒车汽轮机进汽阀开启的时机及幅度进行限制.     

Driver's braking behavior approaching pedestrian crossings: a parametric duration model of the speed reduction times

The driver's braking behavior while approaching zebra crossings under different safety measures (curb extensions, parking restrictions, and advance yield markings) and without treatment (baseline condition) was examined. The speed reduction time was the variable used to describe the driver's behavior. Forty‐two drivers drove a driving simulator on an urban scenario in which the baseline condition and the safety measures were implemented. The speed reduction time was modeled with a parametric duration model to compare the effects on driver's braking behavior of vehicle dynamic variables and different countermeasures. The parametric accelerated failure time duration model with a Weibull distribution identified that the vehicle dynamic variables and only the countermeasure curb extensions affected, in a statistically significant way, the driver's speed reduction time in response to a pedestrian crossing. This result shows that the driver, because of the improved visibility of the pedestrian allowed by the curb extensions, was able to receive a clear information and better to adapt his approaching speed to yield to the pedestrian, avoiding abrupt maneuvers. This also means a reduction of likelihood of rear‐end collision due to less aggressive braking. Copyright © 2016 John Wiley & Sons, Ltd.     

多线预应力混凝土斜拉桥上无缝线路纵向受力与变形

为探讨大跨度斜拉桥上无缝线路纵向受力与变形规律,以一座多线预应力混凝土斜拉桥为例,采用有限元法建立了"塔-索-梁-轨"空间耦合有限元模型,分析了温度荷载、列车荷载以及制动荷载对桥上无缝线路纵向受力与变形的影响。结果表明:当桥塔温度变化时,钢轨伸缩力、钢轨纵向位移和桥梁的纵向位移均无明显变化,钢轨伸缩力最大幅值出现在连续梁两部,并在简支梁梁缝处出现峰值;在列车荷载作用下,各条线路的钢轨挠曲力和钢轨纵向位移随着距加载线路距离的增大而逐渐减小,钢轨挠曲力最大幅值出现在连续梁端部;在制动荷载作用下,钢轨制动力最大幅值出现在连续梁端部,并在加载的起点与终点出现峰值突变,加载的起点或终点与连续梁端部重合时为最不利位置。研究结果可为大跨度斜拉桥上无缝线路设计提供理论参考。     

气动防抱死控制系统设计及仿真

介绍了一种客车ABS控制器开发方法，包括硬件电路设计和控制算法实现，扩展逻辑门限方法对路面的识别，并建立了整车9自由度模型仿真试验台，以半实物仿真的形式对设计的控制器进行了验证，获得较好的控制效果。     

汽车制动性能试验分析软件的开发

本文根据汽车制动的有关理论和标准,建立了汽车制动试验数据采集系统,开发了汽车制动性能试验分析软件,利用所开发的汽车制动系统性能测试系统及分析软件,对某轻型汽车的轴间制动力的匹配进行了深入的研究。结果表明,分析软件具有良好的人机界面、功能较强、对汽车制动性能的研究具有重要的意义。     

车门玻璃升降器制动力矩的分析与计算

对玻璃升降器制动过程进行力学分析并建立了制动力矩的计算公式,可帮助设计人员正确选定结构参数以获得合适的制动力矩。     

高速列车再生制动防滑控制及仿真研究

为了高速列车在制动过程中获得最佳黏着力,防止车轮打滑或空转,需要对电机输出转矩进行控制。为此建立异步电机的数学模型和1/4车辆纵向动力学模型,采用直接转矩控制策略控制电机;采用改进的递归最小二乘法预测黏滑曲线的斜率,以判断车轮处于黏着还是滑动状态;利用滑模变结构算法获得最佳参考制动力矩。变轨面条件下的仿真结果表明,上述方法能够有效使切线力系数保持在最大值附近,使滑移率保持在最佳值附近,从而防止因车轮打滑而损伤轮轨。     

制动模式对城市轨道车辆车轮异常磨耗的影响分析

介绍了城市轨道车辆车轮异常磨耗情况,对由制动模式引起的车轮异常磨耗原因进行了分析,其中包括电制动消失点速度,拖车、动车空气制动力分配比例对车轮异常磨耗的影响等,最后从制动模式角度对有效解决城市轨道车辆车轮异常磨耗的问题提出了若干建议。