汽车列车直线行驶稳定性的模拟试验研究方法

介绍了一种用于研究汽车列车直线行驶稳定性的模型试验系统，该系统由模型试验台和牵引控制系统组成。模型试验台利用环形带模拟活动路面；牵引控制系统通过串行通讯技术操作变频器，结合由传感器采集到的模型列车的运动参数，可实现对模型列车的牵引控制。试验证明，该系统具有较强的实时控制特性，能够满足汽车列车直线行驶稳定性模型试验对试验系统的要求。     

Simulation of Multibody Vehicles Moving over Elastic Guideways1

SUMMARY

This paper describes the present state of a general purpose computer program for calculating the dynamic response of vehicles travelling over guideways which may be elastic.

The linearized state-equations of motion for general multibody vehicles are constructed automatically by the program, these equations are supplemented by the equations for the active subsystems. Finally, the vehicle system equations are combined with the modal equations for elastic guideways and the complete set of coupled equations is solved simultaneously by numerical integration.     

Simulation of Multibody Vehicles Moving over Elastic Guideways1

This paper describes the present state of a general purpose computer program for calculating the dynamic response of vehicles travelling over guideways which may be elastic.

The linearized state-equations of motion for general multibody vehicles are constructed automatically by the program, these equations are supplemented by the equations for the active subsystems. Finally, the vehicle system equations are combined with the modal equations for elastic guideways and the complete set of coupled equations is solved simultaneously by numerical integration.     

液罐汽车直线制动稳定性的分析

对液罐汽车部分装载并直线制动时，罐内液体的质心坐标和制动稳定性进行分析讨论。部分装载的液罐汽车制动行驶时，其质心位置将向前、向上转移，使汽车的同步附着系数减小，造成后桥车轮先于前轴车轮抱死，致使后桥车轮侧向附着力下降而容易发生侧滑；同时还导致前后车轮抱死间隔时间增加。为了减小液罐汽车罐内液体质心的转移对汽车制动稳定性的影响，应在结构上采取措施，尽量控制罐内液体质心的转移量，提高同步附着系数。     

High Speed Stability for Rail Vehicles Considering Varying Conicity and Creep Coefficients

SUMMARY

The critical or hunting speed of solid axle rail vehicles is known to be a strong function of primary suspension stiffness, wheel/rail profile geometry (conicity and gravitational stiffness), wheel/rail friction forces (creep coefficients), bogie/carbody inertia properties, and secondary suspension design. This paper deals with the problem of maximizing the critical speed through design of the primary and secondary suspension but with control only over the range of wheel/rail geometry and friction characteristics. For example, the conicity may varie from .05 to .3 and the linear creep coefficients from 25% to 100% of the predicted Kalker values.

It is shown that the maximum critical speed is greatly limited by the wheel/rail geometry and friction variations. It is also shown that, when lateral curving and ride quality are considered, the best design approach is to select an intermediate primary longitudinal stiffness, to limit the lowest value of conicity (e.g. to .1 or .2) by wheel profile redesign, increasing the secondary yaw damping value (yaw relaxation) and optimizing the primary and secondary lateral stiffness.     

High Speed Stability for Rail Vehicles Considering Varying Conicity and Creep Coefficients

The critical or hunting speed of solid axle rail vehicles is known to be a strong function of primary suspension stiffness, wheel/rail profile geometry (conicity and gravitational stiffness), wheel/rail friction forces (creep coefficients), bogie/carbody inertia properties, and secondary suspension design. This paper deals with the problem of maximizing the critical speed through design of the primary and secondary suspension but with control only over the range of wheel/rail geometry and friction characteristics. For example, the conicity may varie from .05 to .3 and the linear creep coefficients from 25% to 100% of the predicted Kalker values.

It is shown that the maximum critical speed is greatly limited by the wheel/rail geometry and friction variations. It is also shown that, when lateral curving and ride quality are considered, the best design approach is to select an intermediate primary longitudinal stiffness, to limit the lowest value of conicity (e.g. to .1 or .2) by wheel profile redesign, increasing the secondary yaw damping value (yaw relaxation) and optimizing the primary and secondary lateral stiffness.     

非线性闭环汽车系统直线行驶稳定性分析

详细研究了驾驶员－汽车闭环系统直线行驶稳定性问题。在线性范围内分析了驾驶员预瞄时间和轮胎刚度对临界车速的影响；在非线性领域内运用Hopf定理等非线性理论研究了当系统失去直线行驶稳定性后的特殖运动形式，并以某一国产汽车为例，验证了该车失去直线行驶稳定性后，将出现稳定的蛇行运动。     

混合动力汽车传动系统共振转速优化分析

为解决某混合动力汽车传动系统振动和噪声的问题,建立了复合行星轮系和整车传动系统的扭转振动力学模型对该传动系统进行扭转振动分析。在计算传动系统固有频率的基础上,通过扭转减振器的刚度匹配实现共振转速的优化。研究发现,系统在某特定转速比下出现共振特性且在一定范围内随减振器刚度增大而增大;通过减小减振器刚度可以使共振转速远离发动机怠速转速范围,从而提高整车平顺性和乘坐舒适性。     

桁架式桥梁检测车作业稳定性计算探析

对桁架式桥梁检测车（桥检车）的作业稳定性计算工况进行了探析,提出了5种桥检车作业稳定性计算工况和具体的计算方法,在实际应用中验证了其正确性,此桥检车作业稳定性的计算工况和方法对同类产品的稳定性计算具有较大的参考价值。     

公路平直路段运行速度模型分析与优化

对中国现行公路项目安全性评价指南提出的"平直路段运行速度测算模型"中的加速方式进行了分析,通过研究典型路段车流的运行速度规律,找出平直路段测算模型存在的问题,并采用速度微分方程推导、加速时间和加速距离计算、加速曲线绘制等方法对运行速度平直路段的加速方式进行了研究,最终提出"动态加速度"的概念,优化得到能科学表征出平直路段运行速度变化的即时加速度计算方法(动态加速法)。结果表明:动态加速法将即时加速度与即时速度和期望速度有机地联系起来,更好地模拟出汽车在平直路段上的实际加速状态;经与车辆加速曲线图表对比,动态加速法优化和完善了现有平直路段加速度获取方法,具有较强的理论价值和实用价值。     

大跨曲线与直线刚构桥水平双向多点地震反应分析对比

利用多维多点激励的反应谱法对某大跨曲线刚构桥进行了水平双向多点地震反应分析,与相同结构尺寸的直线桥进行对比分析.结果表明:多点激励对于桥墩受力是有利的,减少了桥墩顺桥向响应,且对横桥向响应影响不大;直线桥和曲线桥在水平双向多点激励下桥墩受力相差不大.多点激励对主梁的地震响应是不利的,较大地放大了主梁的地震响应,尤其对主...     

公交停靠站公交车损失时间研究

公交停靠时间影响着公交行程时间、公交准点率以及公交通行能力。文中从理论上阐述了公交停靠站公交车辆停靠时间及其组成部分。为定量分析停靠时间中的损失时间,调查了南京市几个典型的公交停靠站,并综合分析了损失时间的大小、离散程度以及影响因素。研究结果表明,公交泊位数大于2时和公交泊位数小于等于2时的公交车损失时间有很大不同,在泊位数小于等于2的公交停靠站,损失时间较小,且基本保持恒定;在泊位数大于2的公交停靠站,损失时间增大,且受泊位数以及停靠站内已停公交车的影响。     

独柱墩直线梁与曲线梁抗倾覆稳定性对比分析

对独柱墩桥梁横向失稳倾覆机理进行分析,综述目前国内外规范针对桥梁上部结构抗倾覆稳定性计算的有关规定。结合某高架桥工程,选取桥梁位于直线段和曲线段的3跨1联（3×30m）,分别对支座反力、支座底部混凝土强度和桥梁抗倾覆稳定系数进行验算,并对计算结果进行对比分析,所得结论对桥梁独柱墩设计具有一定的参考价值。     

A Simplified Framework for String Stability Analysis of Automated Vehicles*

Automated vehicles traveling in platoons must exhibit stability both individually and as a group, a property referred to as “string stability”. We propose a new framework for evaluating the longitudinal string stability properties of platoons of automated vehicles. In this framework, the platoon is considered to be a mass-spring-damper system with linear characteristics. The resulting closed-loop representation yields transfer functions and impulse responses that can be analyzed to determine the string stability properties of the platoon. This framework facilitates qualitative comparisons of the effects of various controller characteristics, such as time headway and intervehicle communication, on string stability.     

Lateral Stability of Towed Flexible Vehicles

The highway transport of mobile homes is a matter of concern for the increasingly safety-minded driving public. The low speeds of towed vehicles necessary to maintain stability, together with the requirements for excessive lane widths due to clearance for the lateral motion, result in increased likelihood of traffic accidents, impeded traffic flow, and reduced highway capacity. A safe increase in the stable cruising speed, coupled with a decreased amplitude in the pendular motion helps alleviate all three of the aforementioned problems. Energy input at hitch point and lateral forces between the road and tires permit lateral vehicular motions, which occur above a critical speed, to increase in amplitude until possibly a limit cycle or instability is reached. One would expect that structural dynamics could have a pronounced influence on the lateral response of towed vehicles with large and relatively flexible chassis, such as mobile homes. The objective of this research is to determine the influence of chassis structural parameters on the lateral stability of towed flexible bodies during transport. The mass of the towing vehicle is assumed infinitely large, thus eliminating any dynamic interconnection between the towing and towed vehicles. The assumed modes method is used to describe the lateral deflection of the flexible towed vehicle. Results of the study of this model indicate that increase in structural rigidity of towed vehicle increases the critical towing speed whereas increase in the tire cornering coefficient reduces the safe towing speed, which is true only for this simplified model where the dynamic interaction with the towing vehicle is not included.