乘用车滑行阻力与传动系阻力的研究

从汽车滑行运动微分方程入手,利用滑行数据,提出了一种计算汽车滑行阻力与速度关系的新算法,又分别计算得到试验乘用车滑行过程中的滚动阻力、空气阻力和传动系阻力,并且分析了传动系阻力随速度的变化规律。     

汽车滑行阻力系数的测定方法

通过matlab的符号微分方程解法求出汽车滑行运动方程,在给定的阻力系数范围内找到计算数据和采样曲线之间有最小平均偏差的阻力系数,也就是最能拟合滑行采样数据的滚动阻力系数和风阻系数,这种方法的可操作性强而且计算精度可以通过对阻力系数的细分大小来控制。     

基于雷达的近海船舶分布式监控系统

为了实现对近海船舶的监控,将电子海图显示与信息系统(ECDIS)和雷达监控相结合,构建了一种近海船舶分布式监控系统.系统应用于对渔船的监控,结果表明,雷达监控站能够准确传输雷达图像至监控中心,中心监控系统能够实现对近海渔船的监控,说明系统有效、可行.     

牵引电动机无速度传感器带速重投解决方案

为了解决无速度传感器交流牵引传动系统带速重投问题,在分析列车运行状态及牵引电机带速重投问题产生原因的基础上,提出了在列车正常运行中利用再生发电状态取代惰行工况的解决方案,并利用Matlab/Simulink仿真验证了该方法的有效性.以动车组CRH3和电力机车HXD3的参数为例,计算了该方案对列车速度和运行时分的影响.研究结果表明,相对于惰行过电分相,该方法对速度大于200 km/h的动车组造成的速度损失和时间损失均小于2%;对速度大于60 km/h的重载货运列车造成的速度损失和时间损失均小于7%.      

A study on the resistance force and the aerodynamic drag of Korean high-speed trains

The resistance force as well as the aerodynamic drag of Korean high-speed trains including two commercial trains, the KTX and the KTX-Sancheon (KTX-II) and two experimental trains, the HSR-350X and the HEMU-430X have been studied comprehensively. To deduce the aerodynamic drag of the trains, the coefficients of the Davis equation, which is a universal formulation to represent the resistance to motion of the train, have been calculated using the coasting test method and analysed in comparison with those by empirical prediction methods. In case of HEMU-430X train, the equations of resistance to motion have been calculated by an alternative regression method that is established in this study. The results show that the suggested method can successively yield the resistance to motion equation from the coasting test measurements with varying air density by separating the aerodynamic drag from the total resistance of train. It also prevents from improper coefficients which are occasionally taken by normal regression method in irregular coasting condition. After yielding the aerodynamic drag of the trains from the resistance to motion equations, characteristics of the aerodynamic drag have been analysed and compared between the trains.