A vehicle type-based approach to model car following behaviors in simulation programs (case study: Car-motorcycle following behavior)

Traffic simulation models often neglect the important role of motorcycles and assume a flow of various combinations of cars. This paper addresses how much different would be the behavior of a car driver while following a motorcyclist compared to cases in which a car follows another car, along with a segment of an urban highway in the non-congested flow. Recognition of such a difference might help to develop existing simulation models and to improve the behavior of car drivers in such a way to lead to lower accidents with motorcycles. To reach the goal, a GHR (Gazis-Herman-Rothery) model for car following is applied and data have been collected by video cameras during 15?min time intervals in three different days. Analysis of 198 car-motorcycle and 374 car-car following observations has indicated that when a car driver follows a motorcycle, keeps a higher headway (about 10?m in the low speed) with a lower acceleration/deceleration in comparison with the situation in which car driver follow another one. It means that the behavior of the follower car driver would be more cautious compared to situations in which a car driver follows another one, especially in space headways <10?m. In addition to main findings of the paper for developing a more realistic simulation program, the paper also addresses that in cases when the required safe space between a car and a motorcycle would be endangered, a warning message could be generated for the car driver (by implementing an in-veh ITS technology) to warn driver about keeping a safe distance.     

Handling and safety enhancement of race cars using active aerodynamic systems

A methodology is presented in this work that employs the active inverted wings to enhance the road holding by increasing the downward force on the tyres. In the proposed active system, the angles of attack of the vehicle's wings are adjusted by using a real-time controller to increase the road holding and hence improve the vehicle handling. The handling of the race car and safety of the driver are two important concerns in the design of race cars. The handling of a vehicle depends on the dynamic capabilities of the vehicle and also the pneumatic tyres’ limitations. The vehicle side-slip angle, as a measure of the vehicle dynamic safety, should be narrowed into an acceptable range. This paper demonstrates that active inverted wings can provide noteworthy dynamic capabilities and enhance the safety features of race cars. Detailed analytical study and formulations of the race car nonlinear model with the airfoils are presented. Computer simulations are carried out to evaluate the performance of the proposed active aerodynamic system.     

Influence of unsteady aerodynamics on driving dynamics of passenger cars

Recent approaches towards numerical investigations with computational fluid dynamics methods on unsteady aerodynamic loads of passenger cars identified major differences compared with steady-state aerodynamic excitations. Furthermore, innovative vehicle concepts such as electric-vehicles or hybrid drives further challenge the basic layout of passenger cars. Therefore, the relevance of unsteady aerodynamic loads on cross-wind stability of changing basic vehicle architectures should be analysed. In order to assure and improve handling and ride characteristics at high velocity of the actual range of vehicle layouts, the influence of unsteady excitations on the vehicle response was investigated. For this purpose, a simulation of the vehicle dynamics through multi-body simulation was used. The impact of certain unsteady aerodynamic load characteristics on the vehicle response was quantified and key factors were identified. Through a series of driving simulator tests, the identified differences in the vehicle response were evaluated regarding their significance on the subjective driver perception of cross-wind stability. Relevant criteria for the subjective driver assessment of the vehicle response were identified. As a consequence, a design method for the basic layout of passenger cars and chassis towards unsteady aerodynamic excitations was defined.     

Objective evaluation of human perception of automotive sound based on physiological signal of human brain

This paper presents a novel approach to apply the physiological signal of the human brain to the sound quality evaluation of automotive sound. In the previous work, psychoacoustic metrics were applied to the sound quality evaluation of automotive sound. Loudness among psychoacoustic metrics is used for one of major sound metrics for the objective evaluation of the sound quality of the acceleration sound inside a car. Subjective evaluation of the sound quality of the acceleration sound shows different results depending on the two different groups of participants. One group liked powerful sound when a car is accelerated: the other group liked the refine sound. Loudness of the acceleration sound is not correlated with the subjective rating of the former group whilst it is correlated with that of the latter group. This evaluation suggests that for the people who like the powerful acceleration sound, it needs to find the sound metric for the objective evaluation of the sound quality of the acceleration sound. In this paper, a driver’s brain signal is measured using electroencephalography (EEG) when a driver hears the acceleration sound of passenger cars. The signal is analyzed to obtain the relationship between brain signals and human perception. According to these results, the alpha wave correlates to the human perception of powerful sound quality of passenger cars. This interesting relationship can be used for objective evaluation of passenger car sounds.     

汽车维修中常见问题分析及处理方法

如今,汽车已经成为家家户户必不可少的用品,伴随着汽车数量的增多,汽车维修也成为困扰车主的一大问题。本文从现代汽车维修的基本内涵出发,首先分析了汽车维修中的常见问题,其次,本文针对如上分析分析了汽车维修时的注意事项,最后,本文探讨了如上问题的处理和解决方法。希望能给相关工作者以一定的启发。     

Simulation of Vehicle and Power Steering Dynamics Using Tire Model Parameters Matched to Whole Vehicle Experimental Results

This paper uses simulation to investigate how vehicle loading conditions (driver only, passengers, cargo, and fuel) affect power steering system and overall vehicle dynamics. Our purpose of the study was to evaluate the power steering system model for possible use in the National Advanced Driving Simulator (NADS). The effects of changing loading conditions on inertial properties of passenger cars have been found experimentally using a Vehicle Inertia Measurement Facility (VIMF). This paper presents simulation results using a vehicle handling model combined with a power steering system model and a nonlinear tire model. A crucial part of this project was the adjustment of certain parameters of Pacejka's tire model in order to match simulation results with experimental measurements of vehicle and power steering variables in transient maneuvers.     

Simulation of Vehicle and Power Steering Dynamics Using Tire Model Parameters Matched to Whole Vehicle Experimental Results

This paper uses simulation to investigate how vehicle loading conditions (driver only, passengers, cargo, and fuel) affect power steering system and overall vehicle dynamics. Our purpose of the study was to evaluate the power steering system model for possible use in the National Advanced Driving Simulator (NADS). The effects of changing loading conditions on inertial properties of passenger cars have been found experimentally using a Vehicle Inertia Measurement Facility (VIMF). This paper presents simulation results using a vehicle handling model combined with a power steering system model and a nonlinear tire model. A crucial part of this project was the adjustment of certain parameters of Pacejka's tire model in order to match simulation results with experimental measurements of vehicle and power steering variables in transient maneuvers.     

试论汽车驾驶员在安全驾驶中的问题

中国在过去几十年里发生了翻天覆地的变化,社会经济建设取得了重大成就,经济也实现了跨越式发展。目前人们的收入是非常可观的,所以人们有足够的经济支撑购买汽车,这也正是现如今汽车保有量不断增加的主要原因。任何事情都具有双面性,汽车为人们的出行提供了便利,但是其同样会造成交通安全事故,威胁人们生命健康安全。对于汽车驾驶员来讲,道路状况会影响汽车驾驶状态,但对其影响最大的是个人主观因素,即驾驶员驾驶过程中的状态以及心理素质水平的高低。本文主要论述驾驶员在安全驾驶中的问题,并就问题提出解决策略。     

轿车白车身弯扭刚度试验和仿真对比

静刚度在评价汽车安全性与舒适性方面具有举足轻重的作用,白车身刚度试验和仿真是获取刚度参数值的有效手段。文章论述了轿车白车身静态弯曲和扭转刚度试验,并综合考虑对白车身刚度影响的区域,对比分析了不同加载工况下的试验和仿真计算结果,表明弯曲和扭转刚度及门窗调扣变形试验和仿真数据能定量分析车身重要部位的强度,为提出加强或减弱结构的有效措施提供了依据。     

A General Method for the Evaluation of Vehicle Manoeuvrability with Special Emphasis on Motorcycles

This paper presents a novel approach to the assessment of the manoeuvrability of vehicles which is not based on the simulation of open-loop manoeuvres, nor does it rely on the modelling of the driver as a control system. Instead, the essence of the method is the solution of a two-point optimal control boundary value problem, in which a vehicle, subject to physical constraints like tyre adherence and road borders, among others, is required to go between given initial and final positions as fast as possible. The control inputs - i.e., the driver's actions - that make the vehicle move between the two states in the most efficient way are found as a part of the solution procedure and represent the actions of a sort of ideal, perfect driver. The resulting motion is called the optimal manoeuvre and, besides being the most efficient way that the given vehicle has for travelling between the two points according to the chosen optimal criterion, may be taken as a reference for meaningful comparisons with other vehicles. The value of the penalty function, used to define the optimal condition occurring at the optimal manoeuvre, may be taken as a measure of manoeuvrability or handling. With this approach the manoeuvrability properties are established as intrinsic to the vehicle, being defined with respect to an ideal perfect driver. Some possible forms of the penalty function, which means slightly different concepts of manoeuvrability and handling, are discussed. In the end, the case of motorcycles and some examples of optimal manoeuvres are given.     

A General Method for the Evaluation of Vehicle Manoeuvrability with Special Emphasis on Motorcycles

This paper presents a novel approach to the assessment of the manoeuvrability of vehicles which is not based on the simulation of open-loop manoeuvres, nor does it rely on the modelling of the driver as a control system. Instead, the essence of the method is the solution of a two-point optimal control boundary value problem, in which a vehicle, subject to physical constraints like tyre adherence and road borders, among others, is required to go between given initial and final positions as fast as possible. The control inputs - i.e., the driver's actions - that make the vehicle move between the two states in the most efficient way are found as a part of the solution procedure and represent the actions of a sort of ideal, perfect driver . The resulting motion is called the optimal manoeuvre and, besides being the most efficient way that the given vehicle has for travelling between the two points according to the chosen optimal criterion, may be taken as a reference for meaningful comparisons with other vehicles. The value of the penalty function, used to define the optimal condition occurring at the optimal manoeuvre, may be taken as a measure of manoeuvrability or handling. With this approach the manoeuvrability properties are established as intrinsic to the vehicle, being defined with respect to an ideal perfect driver. Some possible forms of the penalty function, which means slightly different concepts of manoeuvrability and handling, are discussed. In the end, the case of motorcycles and some examples of optimal manoeuvres are given.     

汽车外后视镜镜面转向器性能测试机系统设计

随着社会的不断发展,汽车已经走进了千家万户,外后视镜作为汽车驾驶员观察后方情况的重要部件,但由于驾驶员身高、驾驶习惯等因素,需要对外后视镜的镜面角度进行调整。因此,需要对镜面转向器的性能进行测试。亟需一种外后视镜镜面转向器性能测试机,本文提出了一种通用的汽车外后视镜镜面转向器性能测试机系统设计方法。     

高档轿车带天窗项盖冲压工艺方案研究

以东风标致和东风雪铁龙为例,从206到C5,带天窗的顶盖涵盖了中高低三个档次的轿车,随着轿车车身制造水平以及用户对外观要求的不断提高,顶盖天窗的工艺方案成为新项目重点关注点之一。本文从C5天窗顶盖的开发经验总结为依据,结合以前的车型数据,从成本和质量的角度,分析了天窗顶盖冲压工艺方案的特点,并得出针对不同档次的轿车采取不同方案的结论。     

汽车无级变速器传动性能评价系统研究

根据无级变速器电子控制单元的控制算法,结合试验数据,建立了无级变速器(CVT)性能评价系统中的驾驶员模型、发动机模型、无级变速器模型与整车动力学模型。同时给出了各个模型在Simulink中具体的建模方法。最后,针对具体车型,建立了该车型的CVT传动性能的评价系统。     

Passenger car and passenger car–trailer — different tasks for the driver

This paper investigates which different steering reactions are necessary by the driver to avoid obstacles driving a car with or without a trailer. For car and trailer complex 3D-models with nonlinear tyre characteristics are established. The driver modelling extends the well-known 2-level concept with an overruling 3rd level, that will be activated, if unexpected large driver reactions due to the large local path deviations are necessary. The results, comparing these different driver models for car and car–trailer, clearly show the consequences and advantages of the incorporation of a third, extensive reaction level and especially its importance for the car–trailer combination.     

Freight cars shunting impacts analysis using an improved dynamic model of friction draft gear

In this study, simulations of shunting impacts for groups of freight cars that include up to six cars are considered. The simulation technique employs a white-box improved dynamic model of friction draft gear considering all its components and detailed finite element models of the freight cars. The key differences between the one-to-one shunting impact and the impact of long groups of cars in terms of features of the draft gear deflections and the coupler force time history are discussed. We present an example of dynamic finite element analysis for the car body using the coupler force time history obtained from the shunting impact simulation.     

驾驶辅助技术在事故预防中的应用效果

越来越多的车型都搭载了驾驶辅助系统,部分驾驶人对这类系统的实际效果持怀疑态度。本文通过调研国内外相关研究,对几类主流驾驶辅助系统的事故预防效果进行综述。与相同条件下未安装驾驶辅助系统的车辆对比,研究人员发现多数驾驶辅助系统在事故预防方面发挥了明显的作用,降低了相关的事故率、保险索赔率,其中前向和后向的自动紧急制动系统效果最为显著。此外,驾驶人对驾驶辅助系统的接受度以及响应度均会影响事故预防效果。     

基于驾驶员视觉的车辆跟驰建模与仿真

着重从驾驶员心理-生理(AP)跟车模型的角度出发,根据AP模型的不足,提出了驾驶员视觉范围变化对车辆跟车模型的影响,建立跟车模型,并用仿真的方法分析其稳定性,提出了跟车系统稳定性的参数数值范围,以期正确地提出驾驶员的跟车行为。