Possibility of jamming and wedging in the three-piece trucks of a moving freight car

Three-piece trucks have some drawbacks, particularly unstable operation of the friction wedge damping system. One of the principal features of systems of this kind is the possibility of jamming and wedging. This work is devoted to mathematical and numerical modeling of the plane motion of a freight car with allowance for the mobility of the wedges and then for the compliance of the contacting bodies and to the study of the conditions for the onset of jamming and wedging when the car is in motion.     

Wear simulation for the centre plate arrangement of a freight car

The bodies of many railway freight cars in many countries of the world are coupled to the running gear by means of a body centre plate that makes a friction pair with a centre bowl. During motion, the bogie is rotated and moved with respect to the car body. This leads to wear on the contact surfaces. Lubrication is inexpedient in this case because the friction forces damp the vibrations (so-called bogie hunting) during motion. Usually, centre plates exhibit noticeable wear after two years of operation. Reducing wear requires knowing details of the wear process which, in turn, requires computer simulation of freight car motion for an operation period of 10–15 years. The purpose of this paper is to develop a universal method for wear simulation of friction pairs that could be used, in particular, for the centre plate of a freight car.     

智能汽车的运动控制

智能汽车的控制系统从环境感知传感器获得路况信息,通过计算进行动作决策、运动规划,控制智能行驶。对汽车的运动分析、动力分析,得到控制量,是局部路径规划的基础。     

车辆联合供电系统关键技术研究

针对目前车载电源系统存在的MTBF较低等突出问题,提出了车载联合供电系统解决方案,详细介绍了车辆联合供电系统稳压方式的选取、永磁发电机设计原则以及励磁体系的设计方案,并通过建模仿真,进行系统优化,完成了励磁调节器的抗干扰设计。     

Adaptive Control of 4WS System by Using Neural Network

An adaptive control system of the model following type is proposed for drive motion control of a four wheel steering (4WS) car with using neural network (NN) which has mastered nonlinear friction force between tire and road surface. A model of one rigid body is adopted which represents appropriately two kinds of car motion caused by steering action, namely the lateral displacement and the yawing rotation, and an equation of motion is described in a simplified form to make a system equation for motion control possible. Nonlinear relation between the cornering force of tire and the slip angle is obtained by numerical analysis with the tire model proposed by E. Fiala, taking friction coefficient and car speed as the parameters. The result is used as the teaching signal for NN. Three NN are used in the control system composed of both the feed-forward and the feedback circuits in order to realize adaptive control. Validity and usefulness of the proposed adaptive control system with NN are verified by three kinds of computer simulation.     

Adaptive Control of 4WS System by Using Neural Network

SUMMARY

An adaptive control system of the model following type is proposed for drive motion control of a four wheel steering (4WS) car with using neural network (NN) which has mastered nonlinear friction force between tire and road surface. A model of one rigid body is adopted which represents appropriately two kinds of car motion caused by steering action, namely the lateral displacement and the yawing rotation, and an equation of motion is described in a simplified form to make a system equation for motion control possible. Nonlinear relation between the cornering force of tire and the slip angle is obtained by numerical analysis with the tire model proposed by E. Fiala, taking friction coefficient and car speed as the parameters. The result is used as the teaching signal for NN. Three NN are used in the control system composed of both the feed-forward and the feedback circuits in order to realize adaptive control. Validity and usefulness of the proposed adaptive control system with NN are verified by three kinds of computer simulation.     

小汽车与两轮车碰撞运动轨迹模型构建

应用碰撞动力学理论对小汽车与两轮车碰撞过程进行分析,分别构建了小汽车与两轮车碰撞后各自的运动轨迹模型,并运用自编软件实现车辆碰撞运动轨迹的再现仿真;选取碰撞事故案例,将求解结果与PC-Crash软件再现数据对比分析,结果表明模型可信度较高。     

Aerodynamic influence of a passing vehicle on the stability of the other vehicles

The aerodynamic influence of a passing vehicle on the motion stability of other vehicles is discussed. According to the results of wind tunnel tests and actual car tests, it is found that the interference phenomenon can be treated as a quasi-steady problem when relative speed is small. The influence of relative speed on vehicle motion stability is also examined. A small relative speed can affect the vehicle motion because of its long acting time.     

轿车底盘三维参数化总布置设计系统集成研究

介绍了起始于设计需求和技术,包括选型、匹配、性能计算和评估、三维参数化总布置、干涉检查、运动校核以及性能仿真等全过程轿车底盘设计系统集成的开发思路。阐述了基于Pro／E二次开发建立轿车底盘三维参数化总布置设计系统的开发过程,详细描述了该系统开发的基本原理和关键技术。     

高速公路汽车追尾碰撞乘员安全性研究

研究高速公路汽车追尾交通事故中前车乘员颈部运动及其损伤形态,即挥鞭效应。采用有限元动态仿真技术模拟汽车追尾碰撞过程,仿真与试验结果进行对比验证,对应的特征参数基本一致。利用仿真结果分析汽车追尾事故中前车假人颈部的运动损伤特性,并进行安全性评价。结果表明,前车假人颈部的最大前屈和后屈转矩都在评价标准的安全范围之内,但已经接近临界值。研究的结果主要应用于汽车的安全性设计、道路的安全设施配置和交通安全管理等领域。     

Control and evaluation of active suspension for MDOF vehicle model

The current method for solving the problem of active suspension control for a vehicle often uses a quarter car or a half car model. This kind of model is not suitable for practical applications. In this paper, based on considering the influence of factors such as the engine, seat and passengers, a MDOF (multi-degree-of-freedom model) describing the vehicle motion has been set up, and a controller for this model is designed by using LQ control theory. Furthermore the appropriate control scheme is selected by testing various performance indexes.     

Vertical Vibration Analysis of Vehicle/Imperfect Track Systems

Summary This paper studies the vertical vibration of a vehicle traveling on an imperfect track system. The car body and sleepers are modeled as Timoshenko beams with finite length, and the rail is assumed as an infinite Timoshenko beam with discrete supports. Imperfection of the track system comes from a sleeper lost partial support by the ballast. Since deflection of the rail is limited within a certain interval where the vehicle is passing over, the infinite domain problem can be transformed into a finite domain problem with moving boundary. In this work, the equations of motion of the car body, rail and sleepers are discretized first by the finite element method. The discretized equations of motion for the vehicle and track systems are then assembled, respectively. Finally, the Newmark method is applied to obtain the response of the vehicle and track systems at each time step. The effect of the vehicle speed on the response of the vehicle and track systems is investigated.     

汽车动力总成悬置系统位移控制设计计算方法

论述了动力总成位移控制设计的一般原理。以一轿车动力总成4点悬置系统为例,针对汽车的一特殊行驶工况,对动力总成的质心位移、悬置位移和支承点反力进行了计算。文中论述的动力总成位移控制的设计思想和计算方法对汽车动力总成的设计具有指导意义。     

Effect of the Controller Parameters on the Steerability of the Four Wheel Steered Car

The four-wheel-steering systems of the cars are becoming more and more wide-spread. In addition to the conventional 4WS systems (e.g. the steering-wheel-angle dependent four-wheel-steering and the speed dependent 4WS) there already exist some so called active 4WS systems. The front wheels and rear wheels are steered autonomously by the feedback compensation and in this manner the behaviour of the car during high-speed turning manoeuvre and under the side wind gust is improved. But what happens if some of the parameters of the car are changed? In the present paper, the author will analyze the system's response when the internal tyre pressure in the rear wheels is lower than the normal. Due to this the under-steered car becomes over-steered and the question is whether the control system is able to stabilize the motion of the vehicle.     

半开放式差速器的原理及结构优势的探讨

家用汽车与它的四个轮子作为一个整体,在没有打滑的情况下,彼此之间是遵守"同动"效应的,四轮之间的差异只在于运动快慢,即变化的转速比。差速器提供的不限制的转速差远超正常行驶需要,带来了汽车驱动轮单侧空转的弊端并无解。为了解决此种弊端,差速锁直接锁死差速器帮助车子脱困。差速锁不去解决差速器多余转速差,而是关闭差速器消除全部转速差,原理上就走错了方向,这使得它无论采取怎样的工作方式,都很难达到一个理想的效果。而半开放式差速器,在差速器基础上砍掉多余的转速比,原理上这才是正确的方向。     

国产双护盾TBM在兰州市水源地建设工程中的应用

为了研究国产双护盾TBM的工程适应性,结合TBM在兰州市水源地建设工程中的实际应用情况,分析了双护盾TBM掘进段的地质特点,并采取了针对性设计。TBM采用成熟的硬岩刀盘结构形式,滚刀刀座在锻造厚板上一次加工成型,减少焊接量;刀具按照非线性布置,刀间距控制在86 mm以下(含中心刀);主机采取多种针对性设计降低卡盾风险,并预留充足的应急处理接口;后配套系统采用平台式拖车结构,尾部连接四轨双线式会车平台。实践证明,该TBM在兰州市水源地建设工程中具有良好的地质适应性。     

引水隧洞双护盾TBM卡机分析及脱困技术

在不良地质条件下,引水隧洞采用双护盾TBM施工时易发生卡机事故,严重制约工程进度。结合引水隧洞双护盾TBM施工实践,对不良地质条件下双护盾TBM施工中3种常见的卡机类型进行原因归纳与分析,总结出5种卡机脱困技术,并提出双护盾TBM卡机预防措施。实践证明,相应的脱困技术成功地解决了卡机现象。     

Semi-active H∞ control of high-speed railway vehicle suspension with magnetorheological dampers

In this paper, semi-active H∞ control with magnetorheological (MR) dampers for railway vehicle suspension systems to improve the lateral ride quality is investigated. The proposed semi-active controller is composed of a H∞ controller as the system controller and an adaptive neuro-fuzzy inference system (ANFIS) inverse MR damper model as the damper controller. First, a 17-degree-of-freedom model for a full-scale railway vehicle is developed and the random track irregularities are modelled. Then a modified Bouc–Wen model is built to characterise the forward dynamic characteristics of the MR damper and an inverse MR damper model is built with the ANFIS technique. Furthermore, a H∞ controller composed of a yaw motion controller and a rolling pendulum motion (lateral motion+roll motion) controller is established. By integrating the H∞ controller with the ANFIS inverse model, a semi-active H∞ controller for the railway vehicle is finally proposed. Simulation results indicate that the proposed semi-active suspension system possesses better attenuation ability for the vibrations of the car body than the passive suspension system.