Influence of the transmission configuration of a multiple axle vehicle on the obstacle surmounting capacity

Conventional wheeled vehicles have serious mobility limitations in rough terrain while walking vehicles have inherent drawbacks such as a high number of DOF and actuators, control complexity and low-energy efficiency. Vehicles that passively adapt the position of multiple wheels to maintain contact with the ground can be a good compromise between both conventional wheeled and walking vehicles. One way to increase the number of wheels in contact with the ground is using bogies. However, the kinematics of a multiple axle vehicle moving on irregular terrain is quite complex since every wheel can require different angular speed to avoid slippage. The present work aims to quantify the obstacle surmounting capacity of a four axle, double-bogie vehicle depending on the transmission configuration, since it can provoke the slippage of some of its wheels.

Some results are presented corresponding to the vehicle moving on a straight upward slope of different angles and facing variable obstacles in any of its axles.

It can be observed that as more restricted the transmission is, more wheels are forced to slip and less traction the vehicle has, and, as a consequence, less obstacle surmounting capacity.     

S7-200 PLC高速计数器在电子调速器仿真训练器中的应用

高速计数器的主要功能就是对主机实际转速反馈进行测量,这是电子调速器的一项重要功能,因为主机实际转速反馈测量的准确与否直接关系到保证主机转速稳定,保证主机运行的安全.重点介绍了S7-200PLC高速计数器.在开发研制中发现,采用S7-200 PLC高速计数器可以非常准确地对主机实际转速反馈进行测量,而且硬件实现非常简单,价格也比较低,具有很大的实船应用价值.     

基于牵引仿真的列车运行图软冲突疏解方法研究

定义存在于高速铁路列车运行图运行线间的使列车无法在适当功率下运行的软冲突问题,该问题使用既有列车运行图规划方法难以有效解决。分析软冲突形成的机理及其影响,论证牵引供电与列车群一体化仿真计算方法能较好解决软冲突问题,即利用牵引供电计算实现列车运行图软冲突的检测,基于该检测结果进行列车仿真运行调整,从而实现对软冲突的剔除。一体化仿真方法不仅能实现高速列车运行图软冲突的疏解,同时也能得出列车运行过程的操纵策略,并解决了交流牵引供电仿真计算中的某些难点问题。选用我国某一高速铁路线路为例,验证基于牵引仿真的列车运行图软冲突疏解方法。     

Dynamic simulations of the freight three-piece bogie motion in curve

A loaded freight vehicle with two three-piece bogies is modelled using the accessible mathematical software MATLAB. The results are compared with its corresponding ADAMS/Rail dynamic multibody simulation model, where similar derailment factors are encountered for the freight vehicle. Both models reveal that the possibility of derailment increases immediately after entering and at the end of the curve – signifying the beginning and the end of the curve as two major points for derailment. Although a three-piece bogie construction is rather simple, its mathematical model proves to be very complex and is nonlinear due to the reported frictional contact at the rail/wheel interface as well as the friction wedges. This research is stimulated by bogie derailments that have occurred in the Iranian railways as well as those in the rest of the world.     

Sensitivity analysis to assess the influence of the inertial properties of railway vehicle bodies on the vehicle's dynamic behaviour

A sensitivity analysis has been performed to assess the influence of the inertial properties of railway vehicles on their dynamic behaviour. To do this, 216 dynamic simulations were performed modifying, one at a time, the masses, moments of inertia and heights of the centre of gravity of the carbody, the bogie and the wheelset. Three values were assigned to each parameter, corresponding to the percentiles 10, 50 and 90 of a data set stored in a database of railway vehicles. After processing the results of these simulations, the analysed parameters were sorted by increasing influence. It was also found which of these parameters could be estimated with a lesser degree of accuracy for future simulations without appreciably affecting the simulation results. In general terms, it was concluded that the most sensitive inertial properties are the mass and the vertical moment of inertia, and the least sensitive ones the longitudinal and lateral moments of inertia.     

转向架构架的强度评价

介绍了新设计、制造转向架构架及其焊接部位的强度评价方法。     

转辙器轨距加宽对高速道岔动力特性的影响

运用道岔系统动力学理论,考虑轨距加宽式转辙器的结构特性,建立列车/道岔耦合动力学模型,以350 km/h客运专线18号高速道岔为例,计算分析了列车以350 km/h直向及80 km/h侧向过岔时的动力特性.结果表明:转辙器轨距加宽可提高列车直、侧向过岔时的平稳性,降低直向过岔时尖轨的磨耗指数,减轻尖轨侧磨,增加尖轨开始受力截面的轨顶宽度;增大转辙器部位的动轮载、轮缘力及动应力,对尖轨受力不利;转辙器轨距加宽对列车侧向过岔的轮重减载率和脱轨系数有不利影响,对直向过岔的影响不大.因此,建议在我国350 km/h客运专线高速道岔设计中,暂不使用转辙器轨距加宽技术.     

纳米比亚机车米轨径向转向架简介

主要介绍出口纳米比亚机车径向米轨转向架的结构特点、技术参数和主要性能。利用计算机仿真技术对其结构进行了优化,并对其动力学性能进行预测。     

京沪高速铁路广阳梁场冬期施工技术

以京沪高速铁路广阳梁场冬期制梁为例,详细介绍了制梁台座、存梁台座、钢筋加工区、搅拌站以及混凝土搅拌与浇筑保温措施,箱梁蒸汽养护温度控制技术和预应力孔道压浆养护方法。     

18t轴重160km／h货车转向架的研制

介绍了18t轴重160km/h货车转向架的研制过程及技术参数、结构特点和有关试验情况。