The Dynamics of Single Track Vehicles

SUMMARY

The paper contains a brief review of the more subjective aspects of the steering behaviour of single track vehicles, a review of the more significant published work in the field, and an assessment of the current state of understanding and likely ways in which further progress can be made

Attention is drawn to the many areas of agreement between theory and practice and to some areas of disagreement. The greatest need now seems to be for the incorporation of more complex tyre models into vehicle handling models.     

A review on motorcycle and rider modelling for steering control

The paper is a review of the state of knowledge and understanding of steering control in motorcycles and of the existing rider models. Motorcycles are well known to have specific instability characteristics, which can detrimentally affect the rider's control, and as such a suitable review of these characteristics is covered in the first instance. Next, early models which mostly treat riding as a regulatory task are considered. A rider applies control based on sensory information available to him/her, predominantly from visual perception of a target path. The review therefore extends to cover also the knowledge and research findings into aspects of road preview control. Here, some more emphasis is placed on recent applications of optimal control and model predictive control to the riding task and the motorcycle–rider interaction. The review concludes with some open questions which naturally present a scope for further study.     

Handling Characteristics of Car-Trailer Systems; A State-of-the-Art Survey

Work relevant to the state of the art as regards passenger cars towing trailers is referenced and reviewed. Not only included is the very limited amount of work specifically dealing with passenger cars towing trailers, but also reviewed is the much larger body of work having a bearing on car-trailer systems. Topics included are aerodynamic forces, tire forces, the compliance concept, relevant work on vehicles without trailers, vehicles with trailers, and the role of the driver. The types of stability problems exhibited by car-trailer systems are discussed.

The state of the art as regards ability to predict vehicle response to specific steering inputs is shown to be fairly advanced. Recent significant advances include the appearance of experimental data useful for validating theoretical models. However, the state of the art as regards definition of what constitute desirable handling characteristics is still at a primitive stage, largely because of a lack of understanding of the roles played by drivers as part of the vehicle -driver - environment systems.

Throughout the review an effort was made to point out topic areas where it is likely that significant future contributions to the state of the art can be made. These areas are reviewed in the conclusions.     

斜拉桥钢锚拉板区域焊接应力消除试验研究

对重庆江津观音岩大桥索梁锚固区域部分进行了3个足尺比例试件的焊接残余应力测试,并对其焊缝进行了超声波冲击试验,以研究超声波冲击对钢锚拉板区域各焊缝应力的影响情况。测试和试验研究结果表明,钢锚拉板区域各焊缝存在着相当大的焊接残余应力,特别是在平行于焊缝长度方向的应力,不少测点已接近屈服强度。通过采用超声波冲击工艺,大幅度地减小和消除了该区域的焊缝残余拉应力,3个试验试件的各焊缝在平行和垂直于焊缝长度方向的应力平均下降50%以上,最大的下降96.5%,不少测点应力已由拉应力变为了压应力,有效地改善了应力的状态,从而使结构的受力更合理,应力分布趋于均匀。超声波冲击可以作为一种解决斜拉桥桥钢锚拉板区域焊接应力过大问题的有效的方法,对提高接头的疲劳寿命有明显作用。     

汽车平台及通用化研发模式探索

汽车平台化研发有助于快速推出新车型，欧洲汽车主机厂的平台化不仅体现在看得见的地方（内外饰等），更体现在看不见的地方（底盘、机舱等），强调相同设计。亚洲主机厂的平台化与欧洲主机厂则有一定的区别，更强调相似设计。汽车平台化研发模式需要对车型研发、采购、生产等综合考虑。文章通过对全球主流主机厂进行调查，探索目前汽车厂商的平台化研发及此研发模式各个车型间的零部件通用性。     

公路车-桥耦合振动的理论和应用研究进展

为了推动公路车-桥耦合振动理论的发展和仿真技术的广泛应用,从公路车-桥耦合振动理论研究和应用研究2个方面系统性梳理了公路车-桥耦合振动相关领域的学术研究现况、既有研究成果、发展前景、存在的问题和对策。理论研究方面,系统总结了车-桥耦合振动研究中车-桥、桥梁、路面不平整度等参数的数学模型和车-桥耦合时变系统动力学方程的数值解法。基于调研和分析发现,经过国内外学者长期的努力,车-桥系统数值模型已经可以越来越真实地模拟实际车辆、桥梁以及路面不平整度等其他条件因素。在未来的研究中应持续改进有限元建模技术和优化数值算法,以进一步提高车-桥耦合振动仿真分析的精度和效率,扩展其应用范围。应用研究方面,以桥梁动力冲击系数、桥梁疲劳分析、桥梁结构损伤识别、桥梁振动控制、桥上行车舒适性以及桥上车辆荷载动态识别等6个问题为例,综述了车-桥耦合振动仿真技术在桥梁安全相关研究领域的应用现状,并对目前研究仍存在的局限和后续的研究方向进行了初步探讨。研究表明,车-桥耦合振动仿真技术已成为众多相关研究领域内的重要研究方法,在部分研究领域已展现了良好的应用前景。后续研究中,一方面应针对具体问题的特点改进车-桥耦合振动模型的适用性和计算精度,另一方面应针对具体研究问题进一步完善相关理论,并从工程实用性角度提出新的或改进的技术和方法。     

Lateral dynamics of motorcycles towing single-wheeled trailers

A motorcycle towing a single-wheel trailer may provide useful transport for light cargo on narrow tracks and off-road use, particularly in rural areas of developing countries. Four designs of such trailers are described. Linear models are derived for the lateral dynamics of an off-road motorcycle towing this type of trailer straight ahead at constant speed. The trailers were tested behind an instrumented motorcycle. Linear autoregressive models were fitted to the experimental data using system identification techniques. Analytical and experimentally derived models largely agreed on frequency, damping and shape of the weave, wobble and trailer sway normal modes. The trailers made the motorcycle's steering heavier but the analytical models did not predict this. The location of the articulation axes between the motorcycle and the trailer were found to be critical for stability. The best trailer design handled well with loads up to 200 kg and speeds up to 70 km/h.     

Lateral dynamics of motorcycles towing single-wheeled trailers

A motorcycle towing a single-wheel trailer may provide useful transport for light cargo on narrow tracks and off-road use, particularly in rural areas of developing countries. Four designs of such trailers are described. Linear models are derived for the lateral dynamics of an off-road motorcycle towing this type of trailer straight ahead at constant speed. The trailers were tested behind an instrumented motorcycle. Linear autoregressive models were fitted to the experimental data using system identification techniques. Analytical and experimentally derived models largely agreed on frequency, damping and shape of the weave, wobble and trailer sway normal modes. The trailers made the motorcycle’s steering heavier but the analytical models did not predict this. The location of the articulation axes between the motorcycle and the trailer were found to be critical for stability. The best trailer design handled well with loads up to 200 kg and speeds up to 70 km/h.     

隧道数值模拟计算边界范围研究

本文以某高速公路隧道的开挖和支护过程为工程实例,采用有限差分法岩土分析软件Adina进行全过程模拟,旨在分析模型的边界效应对相应求解精度的影响。研究方法是在其它条件同等的情况下,采用不同的模型边界范围建模,并分别独立进行模拟求解,通过比较不同模型下同一截面的力学响应的差异,进而分析模型边界范围这一单因素对隧洞开挖数值模拟的精度影响。研究思路和结论可以为类似的数值模拟关于如何合理地选择模型边界范围提供参考,从而使模拟实现过程的时效性和精度达到较佳的统一。     

基于GIS分析的深圳市道路交通事故空间分布特征研究

掌握城市道路交通事故空间分布特征是城市道路交通安全管理的重要基础。基于深圳市2014~2016年的道路交通事故数据,首先应用地理编码方法对原始事故记录进行空间定位,形成事故的空间分布。其次针对考虑/不考虑路网密度的2种情况,应用密度分析方法对道路交通事故多发的区域和事故严重程度较高的区域进行鉴别,比较2种情况下区域分布的差异并分析造成这种差异的可能原因。最后利用异常点分析和热点分析2种空间聚类分析模型对事故严重程度较高的区域进行进一步鉴别,并对密度分析和聚类分析2种方法得到的结果进行了比较。密度分析结果表明：就事故频度而言,深圳市中心城区单位面积上的交通事故频度较高,而郊区单位长度道路上的交通事故分布更为密集;就事故严重程度而言,郊区的交通事故平均严重程度高于市中心区域。造成上述差异的原因可能与郊区道路限速较高等因素有关。聚类分析结果与密度分析结果相近,在郊区形成了高严重程度的事故聚类,而在中心城区形成了低严重程度的事故聚类,说明郊区的交通事故严重程度总体高于市中心区域。从2种方法的比较来看,密度分析简单易行,有助于交通管理部门对城市交通事故空间分布特征直观快速的了解;聚类分析可精确到事故点,为精细化的交通安全管理工作提供支撑。研究结果表明基于密度分析和聚类分析的研究方法对于确定道路交通事故空间分布特征有良好的作用。     

Modeling the Effects of Population Density on Prospect Theory-Based Travel Mode-Choice Equilibrium

In conventional transportation planning models, it was always assumed that the population density is given and fixed in the study areas. Therefore, the effects of population density on travel choice have not been explicitly incorporated into these existing models for long-term transportation planning. Meanwhile, travel choice models in previous studies are usually developed by using discrete choice theories or user equilibrium principle. Thus, many significant characteristics of travelers’ behaviors, such as risk preference and learning process over time, cannot be considered in these conventional models. This article proposes a convex prospect theory-based model to investigate the effects of population density on the travelers’ mode-choice behavior under an advanced transportation information system (ATIS) in a multimodal transportation corridor. It is shown that population density is closely co-related to the modal split results and dependent on the performance of the railway mode in the study corridor. The park-and-ride mode may not be suitable for areas with high population density. This article also investigates the travelers’ reference points on the generalized travel costs by modes. A numerical example is given to illustrate the properties of the proposed model together with some insightful findings.     

Longitudinal Tire Dynamics

This article begins with a brief review of the traditional concept of lateral relaxation length. The review illustrates that this concept yields a useful approximation which can be used with semi-empirical tire models which assume lateral forces are a function of steady-state slip angles. The article then presents an analogous derivation for longitudinal slip. Like its lateral counterpart, the derivation yields an approximation for transient longitudinal slip which can be used with tire models which assume longitudinal forces are a function of steady-state longitudinal slip. It is shown that, like the relaxation-length-based lateral slip angle, this formulation for longitudinal slip yields the ability to compute shear forces at the tire/road interface for either high or low speed applications, a necessary feature of simulations which support human in the loop driving simulation. Like traditional kinematically-based longitudinal slip, the transient formulation presented here is coupled with the wheel spin equation, and it shares the characteristic that it is very stiff compared to the equations of vehicle motion. This characteristic is a challenge impeding the real-time calculations required for driving simulation. The paper shows that local linearization of the wheel spin equations coupled with analytical solutions of the transient longitudinal slip formulation provide the basis for both insight into the longitudinal dynamics of the tire and for integrating the model in real-time.     

汽车前风窗玻璃刮水器刮扫区域的计算机确定及校核

本文论述了利用ＩＣＥＭ ＤＤＮ图形软件中的ＧＰＬ用户程序设计语言，按照ＳＡＥ工程标准编制程序，实现从眼椭圆的定位，绘制，汽车前风窗玻璃扫刮区域和除霜区域的确定及校核方法，并以ＣＡ１４１汽车驾驶室为工作实例进行校核。作者用ＧＰＬ设计的程序移植到其它ＣＤＣ主机，在ＮＯＳ操作系统，ＪＣＥＭ ＤＤＮ软件环境下运行，实现参数化设计。     

Shear Force Development by Pneumatic Tyres in Steady State Conditions: A Review of Modelling Aspects

SUMMARY

Modelling of the generation of shear forces by pneumatic tyres under steady state conditions is reviewed. The review is placed in a practical context, through reference to the uses to which models may be put by the vehicle dynamicist and the tyre designer. It will be of interest also to the student of rolling contact problems.

The subject is divided into sections, covering physically founded models which require computation for their solution, physically based models which are sufficiently simplified to allow analytical solutions and formula based, empirical models. The classes are more nearly continuous than this strict division would imply, since approximations in obtaining analytical solutions may be made, empirical correction factors may be applied to analytical results and formula based methods may take into account tyre mechanical principles. Such matters are discussed in the relevant sections. Attention is given to the important matter of choosing model parameters to best represent the behaviour of a particular tyre.

Conclusions relate to the structural and frictional mechanisms present in the shear force generation process, the contributions of carcass and tread elastic properties and of geometrical and frictional factors to the determination of the distributions of force through the contact region, the relationship between accuracy and computational load and the selection of methods for modelling tyre forces in a road vehicle dynamics context. Reference to the most pertinent literature in the field is made and possibilities for the further development of the state of the art are mentioned.     

手动挡汽车起停系统技术与应用

介绍了某款手动挡车起停系统的开发应用,包括系统方案、起停零部件开发、起停控制逻辑、油耗对比试验。试验结果证明,采用起停技术后车辆在市区工况油耗可以降低至少6.5%,可以满足第三阶段油耗要求(7.7L/100km),证明起停技术是一种有效的整车节油手段,可以用于大批量生产。     

Longitudinal Tire Dynamics

SUMMARY

This article begins with a brief review of the traditional concept of lateral relaxation length. The review illustrates that this concept yields a useful approximation which can be used with semi-empirical tire models which assume lateral forces are a function of steady-state slip angles. The article then presents an analogous derivation for longitudinal slip. Like its lateral counterpart, the derivation yields an approximation for transient longitudinal slip which can be used with tire models which assume longitudinal forces are a function of steady-state longitudinal slip. It is shown that, like the relaxation-length-based lateral slip angle, this formulation for longitudinal slip yields the ability to compute shear forces at the tire/road interface for either high or low speed applications, a necessary feature of simulations which support human in the loop driving simulation. Like traditional kinematically-based longitudinal slip, the transient formulation presented here is coupled with the wheel spin equation, and it shares the characteristic that it is very stiff compared to the equations of vehicle motion. This characteristic is a challenge impeding the real-time calculations required for driving simulation. The paper shows that local linearization of the wheel spin equations coupled with analytical solutions of the transient longitudinal slip formulation provide the basis for both insight into the longitudinal dynamics of the tire and for integrating the model in real-time.     

高速公路互通立交安全性评价研究综述

高速公路互通立交区道路、交通和行车环境条件的复杂程度远高于基本路段,是制约高速公路运行安全和通行效率的瓶颈路段。互通立交安全性评价研究虽取得了一系列成果,但离实际应用仍有一定差距,有必要对其研究现状进行回顾、总结与展望。为此,针对互通立交安全性评价研究进行系统梳理和总体框架搭建,将其具体分为人因工程理论、交通冲突理论、运行速度协调理论三大理论,事故统计法和层次分析法两大方法,并对其进行综合评述。研究结果表明:人因工程理论适用于主线和匝道的安全性评价,能更准确排查行车安全隐患点、段,但应考虑车辆类型和合理的试验样本量,提高评测指标的稳定性;交通冲突理论适用于主线上存在明显交通冲突区域的安全性评价,但未考虑道路条件对安全性的影响,且应进一步完善交通冲突评价指标体系、划分阈值以及分、合流形式的研究;运行速度协调理论较为成熟,已应用于高速公路基本路段的安全性评价,但主线和匝道的运行速度段落划分和预测模型精度均有待进一步提高;事故统计法的结论客观可靠,但事故数据统计和共享难度大,层次分析法可确定安全性评价的重点内容和关键影响因素,但评价结果主观性较强,2种方法的适用性均存在较大限制。未来研究应针...     

基于交通安全的高速公路交织区构型研究

针对现有8种高速公路交织区构型,通过对其重要因素如交织区构型、交织区长度、交织区宽度、交织流量等进行分析,建立其冲突因子模型,并利用模型对其进行重新划分,以为高速公路交织区的设计及管理提供借鉴。     

高速公路平面线形与安全关系的探讨

建立线形指标、交通量与事故间的模型是当前事故规律微观研究的主要方法，虽然在模型中纳入更多的指标能够提高的解释能力，但增加了模型的复杂性，加剧了数据采集困难．简洁的模型有时候在分析特定类型事故时反而更具优势，因此，作者在研究高速公路线形条件与事故的关系时，主要提取了平面线形的圆曲线、缓和曲线和超高等指标，重点分析平面线形与安全的关系。作者首先对国内外有关平面线形与安全关系的研究进行了简要回顾，利用贵州省贵黄、贵新两务高速公路的事故、线形、交通量数据建立了回归模型。此外，还结合具体案例，对曲线超高对行车安全的影响进行了剖析，并提出了一些针对平面线形安全问题的具体措施和建议。     

细节的力量——东风天锦“精准传播,‘遍地开花’”培训交流会带来的启示

2011年,受到宏观政策、金融政策等多方面因素的影响,国内重卡行业呈现了较大幅度的下滑。与之相比,中卡由于拉载货物及运输情况的特性,其销售仍然保持了平稳增长。但与此同时,中卡市场的竞争则变得更加激烈。据东风商用车中型车品系部统计,2010年参与中卡竞争的企业有28家,包括一些针