针对行人保护头部仿真分析中雨刮臂的接触设置研究

利用计算机进行有限元仿真分析,在汽车行人保护性能开发过程中有着广泛的应用。对于行人保护建模来说,风挡玻璃区域应按照实际情况对玻璃进行准确建模,然而对于风挡玻璃与雨刮器采用以往的接触设置,雨刮臂与玻璃产生穿透现象。因此为了解决穿透问题,准确模拟出其实际运动关系,对于雨刮臂与风挡玻璃之间的接触设置研究是非常有必要的。     

Development of probabilistic pedestrian fatality model for characterizing pedestrian-vehicle collisions

Pedestrian-related accidents are considered to be the most serious of traffic accidents due to the associated high fatality rates. In Korea, pedestrian fatalities accounted for approximately 40% of all traffic-related fatalities in 2004. Significant efforts have been made to develop effective countermeasures for pedestrian-vehicle collisions. A basis for devising such countermeasures is to understand the characteristics of pedestrian-vehicle collisions. This study develops a pedestrian fatality model capable of predicting the probability of fatality in pedestrian-vehicle collisions. Binary logistic regression and a probabilistic neural network (PNN) are employed to estimate the probability of pedestrian fatality. Pedestrian age, vehicle type and collision speed are used as independent variables of the fatality model. The models developed herein are valuable tools that can be used to direct safety policies and technologies associated with pedestrian safety.     

Risk assessment based on driving behavior for preventing collisions with pedestrians when making across-traffic turns at intersections

Traffic accident statistics in Japan show the necessity of preventing vehicle-on-pedestrian accidents. If the risk of a vehicle colliding with pedestrians could be evaluated in advance, driver-assistance systems would be able to support drivers to avoid potential collisions. Here, features of driving behavior and methods for assessing the risk of collision were investigated for a right turn at an intersection in left-hand traffic, which is a typical vehicle-on-pedestrian accident scenario. The results showed that pedestrian-collision risk can be evaluated from how the driver slows the vehicle and where the driver looks while turning during the maneuver. Moreover, pedestrian-collision risk could be predicted based on driving behavior upon commencement of steering when making an across-traffic turn.     

Estimation of delay variability at signalized intersections for urban arterial performance evaluation

Urban arterial performance evaluation has been broadly studied, with the major focus on average travel time estimation. However, in view of the stochastic nature of interrupted flow, the ability to capture the characteristics of travel time variability has become a critical step in determining arterial level of service (LOS). This article first presents a stochastic approach that integrates classic cumulative curves and probability theories in order to investigate delay variability at signalized intersections, as a dominant part of the link travel time variability. This serves as a basis for arterial travel time estimation, which can be obtained through a convolution of individual link travel time distributions. The proposed approach is then applied in the estimation of travel time along one arterial in Shanghai, China, with abundant automatic vehicle identification (AVI) data sources. The travel time variability is evaluated thoroughly at 30-min intervals, with promising results achieved in comparison to the field measurements. In addition, the estimated travel time distributions are utilized to illustrate the probability of multiple LOS ranges, namely, reliability LOS. The results provide insights into how we might achieve a more reliable and informative understanding of arterial performance.     

几何设计对快速路立交匝道行车安全性的影响

由于城市快速路转向交通流量大、线形设计标准低,快速路立交匝道成为交通事故的多发点。利用上海市快速路3年事故数据和交通流量检测数据,以上海市浦西地区快速路立交匝道为研究对象,根据车辆在匝道上的行驶特征以及车辆交互特性,将立交匝道划分成出口段、衔接段和入口段及左转匝道、右转匝道等5个研究单元,针对各单元分别建立负二项模型分析匝道几何设计及其组合参数、交通流特征对于安全的影响。结果表明,出口段及入口段的安全性与几何特征的联系较为紧密;迂回式左转匝道相较于右转匝道受几何线形影响大;流量越大、长度越长,事故风险越高,但出口段的长度与事故发生呈负相关关系;出口处为直线、入口处存在长直下坡路段、入口处线形与主线差异大的立交匝道安全性差;迂回式左转匝道上存在过小半径曲线,特别是将小半径曲线设置在出口处,会极大增加事故几率。     

A list of accident scenarios for three legs skewed intersections

The term ‘scenario’ is used in the safety field to designate a prototype or a model of an accident process characterised by chains of facts, actions, causal relations and consequences in terms of damage to people and property. The prototypical scenarios, properly realized, provide a basis on which to consider the action to be taken, but also a concrete backup for accident information for use in information campaigns or training. The objective of this study is to define the prototypical accident scenarios for a particular configuration of road intersection: the skewed intersection. Limited sight distance at skewed intersections leads to safety issues. A non-skewed intersection provides the best operating conditions as drivers can easily sense the direction in which they are travelling, estimate the speeds of the opposing traffic and smoothly complete a maneuver in shorter time. In skewed intersections, instead, the ability of drivers to recognize any conflicting vehicles diminishes in comparison to right-angle intersections. The logical-deductive approach used in this paper for the determination of accident scenarios is based on an analysis of a large database of incidents, which occurred on several roads in eastern Sicily on 35 skewed intersections at three-legs. The skew angle of the minor leg of all the intersections studied is between 15° and 20°. This research allowed to develop accident scenarios related to particular configurations of intersections, compatible with the Italian rules. Prototypical scenarios are constructed using samples of accidents occurring on a particular type of study area, especially when they are based on files from in-depth investigations. The method used is an inductive approach, based on an examination of each case, grouping together similar cases and building a prototypical scenario using this case grouping. From the in-depth analysis of database accidents 9 prototypical accident scenarios have been identified for the skewed intersections.     

基于行人保护的SUV前保险杠防撞系统优化

为减小SUV车型在人车碰撞中对行人小腿的伤害,文章对SUV车型前保险杠造型进行了优化。分析了上支撑与下支撑布置和材料对小腿碰撞伤害值的影响,结果表明,当前保险杠上支撑安装位置处于小腿上部质心以下时,上支撑与小腿上部质心距离及上支撑材料对胫骨加速度值影响较大,上支撑与下支撑距离与下支撑材料对剪切位移影响较大。采用优化后的前保险杠防撞系统有效地控制了行人小腿伤害值,有利于该车型行人保护性能的提升,为以后SUV车型行人保护前保险杠防撞系统设计提供一些参考。     

半主动悬架的控制策略探讨

综述汽车悬架控制系统的基本类型,以半主动悬架为研究对象,推导建立汽车两自由度1/4车体模型,提出一种汽车半主动悬架系统的模糊控制方法,并利用MATLAB进行仿真,结果证明该控制策略有效.     

The perspectives of research for enhancing active safety based on advanced control technology

This paper considers the scope and the methodologies for enhancing active safety of road vehicles by sensing and control technologies. The first part of this paper introduces statistical data of traffic accidents in Japan, and describes the development of the drive recorder for accident/incident survey and analysis. Based on vehicle dynamics data, the algorithm of the drive recorder for capturing near-miss incident data is introduced. The second part of this paper reviews control problems of vehicle dynamics on micro-scale electric vehicles for enhancing vehicle dynamics and driving assistance function. In particular, the direct yaw moment control using in-wheel-motors and the active front steering control algorithm are described. The third part of the paper introduces the advanced driver assistance system adapted to driver characteristics and traffic situations. This part mainly describes an adaptive system, which adjusts the assisting manoeuvre depending on individual driver behaviour and situation, and some experimental investigations using the active interface vehicle and driving simulator. Finally, some perspectives and new challenges for future research on vehicle control technology are mentioned.     

Application of viability theory for road vehicle active safety during cornering manoeuvres

Viability theory proposes geometric metaphors in addition to classical ordinary differential equation analysis. In this paper, advantages of applying viability theory to road safety domain are presented. The exact issue is to determine if, from an initial state of a vehicle/road/driver system, a soft controls strategy is compatible with a safe driving sequence. The case of a car negotiating a curve is considered. The application of the viability theory to this issue offers the advantage to avoid classical full computing of the system. Instead of that, it consists on verifying that the states and the controls belong to a subset called the viability kernel. The construction and the use of the viability kernel for a vehicle system dynamic is proposed by using support vector machines algorithm. Then, the applicability of this theory is demonstrated through experimental tests. This innovative application of the viability theory to vehicle dynamics with road safety concerns could benefit to robust embedded warning systems.     

Understanding the limitations of different vehicle models for roll dynamics studies

An accurate and realistic vehicle model is essential for the development of effective vehicle control systems. Many different vehicle models have been developed for use in various vehicle control systems. The complexity of these models and the assumptions made in their development depend on their application. This article looks into the development and validity of vehicle models for prediction of roll behavior and their suitability for application in roll control systems. A 14 DOF vehicle model that includes dynamics of roll center and nonlinear effects due to vehicle geometry changes is developed. The limitations, validity of simplified equations, and various modeling assumptions are discussed by analyzing their effect on the model roll responses in various vehicle maneuvers. A formulation of the popular 8 DOF vehicle model that gives good correlation with the 14 DOF model is presented. The possible limitations of the 14 DOF model compared with an actual vehicle are also discussed.     

Understanding the limitations of different vehicle models for roll dynamics studies

An accurate and realistic vehicle model is essential for the development of effective vehicle control systems. Many different vehicle models have been developed for use in various vehicle control systems. The complexity of these models and the assumptions made in their development depend on their application. This article looks into the development and validity of vehicle models for prediction of roll behavior and their suitability for application in roll control systems. A 14 DOF vehicle model that includes dynamics of roll center and nonlinear effects due to vehicle geometry changes is developed. The limitations, validity of simplified equations, and various modeling assumptions are discussed by analyzing their effect on the model roll responses in various vehicle maneuvers. A formulation of the popular 8 DOF vehicle model that gives good correlation with the 14 DOF model is presented. The possible limitations of the 14 DOF model compared with an actual vehicle are also discussed.     

A novel global sensitivity analysis on the observation accuracy of the coupled vehicle model

ABSTRACT

This paper proposes a novel 2-step global sensitivity analysis algorithm to provide an in-depth sensitivity analysis of the vehicle parameters on the system responses. A 9 degree-of-freedom nonlinear vertical–lateral coupled vehicle model is developed, and 12 parameters along with 7 system responses are selected for the sensitivity analysis. In order to reduce the computational effort, the proposed 2-step algorithm calculates the elementary effects and selects 7 influential parameters from these 12, and then uses the Sobol' method to obtain the global sensitivity indexes of these influential parameters. An unscented Kalman filter is finally designed to show the effect and importance of the selected sensitive parameters on the observation accuracy. Simulations with different vehicle types, velocities and tyre models have verified that the proposed algorithm can accurately describe the relationship between the vehicle parameters and system responses, which is of directive significance to improve vehicle controller and observer performances.     

占道施工区交通安全分析与对策研究

以安全与畅通为重要目标,首先介绍了国内外研究概况;其次从5个方面入手分析了占道施工区的安全特性,即占道施工区的基本组成,国内外占道施工区事故的统计分析,交通参与者、道路、安全设施及其设置等方面影响安全的主要因素;最后,从加强宣传培训、优化设施设置和严格管理监督5个方面提出安全对策。     

Estimation of longitudinal speed robust to road conditions for ground vehicles

This article seeks to develop a longitudinal vehicle velocity estimator robust to road conditions by employing a tyre model at each corner. Combining the lumped LuGre tyre model and the vehicle kinematics, the tyres internal deflection state is used to gain an accurate estimation. Conventional kinematic-based velocity estimators use acceleration measurements, without correction with the tyre forces. However, this results in inaccurate velocity estimation because of sensor uncertainties which should be handled with another measurement such as tyre forces that depend on unknown road friction. The new Kalman-based observer in this paper addresses this issue by considering tyre nonlinearities with a minimum number of required tyre parameters and the road condition as uncertainty. Longitudinal forces obtained by the unscented Kalman filter on the wheel dynamics is employed as an observation for the Kalman-based velocity estimator at each corner. The stability of the proposed time-varying estimator is investigated and its performance is examined experimentally in several tests and on different road surface frictions. Road experiments and simulation results show the accuracy and robustness of the proposed approach in estimating longitudinal speed for ground vehicles.     

Advanced vehicle dynamics of heavy trucks with the perspective of road safety

ABSTRACT

This paper presents state-of-the art within advanced vehicle dynamics of heavy trucks with the perspective of road safety. The most common accidents with heavy trucks involved are truck against passenger cars. Safety critical situations are for example loss of control (such as rollover and lateral stability) and a majority of these occur during speed when cornering. Other critical situations are avoidance manoeuvre and road edge recovery. The dynamic behaviour of heavy trucks have significant differences compared to passenger cars and as a consequence, successful application of vehicle dynamic functions for enhanced safety of trucks might differ from the functions in passenger cars. Here, the differences between vehicle dynamics of heavy trucks and passenger cars are clarified. Advanced vehicle dynamics solutions with the perspective of road safety of trucks are presented, beginning with the topic vehicle stability, followed by the steering system, the braking system and driver assistance systems that differ in some way from that of passenger cars as well.     

基于主动安全的轮间电控限滑差速器控制方法研究

论述了电控限滑差速器(ELSD)改善汽车动力学特性的原理,提出了基于提高汽车主动安全性的控制方法。该方法利用前馈与误差反馈控制相结合来控制车辆运动状态。反馈系数根据最优控制的方法确定。通过对所述控制系统的仿真研究,证明该系统在各种路面条件下均可明显改善汽车的操纵稳定性与主动安全性。     

Fault classification method for the driving safety of electrified vehicles

A fault classification method is proposed which has been applied to an electric vehicle. Potential faults in the different subsystems that can affect the vehicle directional stability were collected in a failure mode and effect analysis. Similar driveline faults were grouped together if they resembled each other with respect to their influence on the vehicle dynamic behaviour. The faults were physically modelled in a simulation environment before they were induced in a detailed vehicle model under normal driving conditions. A special focus was placed on faults in the driveline of electric vehicles employing in-wheel motors of the permanent magnet type. Several failures caused by mechanical and other faults were analysed as well. The fault classification method consists of a controllability ranking developed according to the functional safety standard ISO 26262. The controllability of a fault was determined with three parameters covering the influence of the longitudinal, lateral and yaw motion of the vehicle. The simulation results were analysed and the faults were classified according to their controllability using the proposed method. It was shown that the controllability decreased specifically with increasing lateral acceleration and increasing speed. The results for the electric driveline faults show that this trend cannot be generalised for all the faults, as the controllability deteriorated for some faults during manoeuvres with low lateral acceleration and low speed. The proposed method is generic and can be applied to various other types of road vehicles and faults.     

Assessment of the influence of the elastic properties of rail vehicle suspensions on safety,ride quality and track fatigue

A sensitivity analysis has been performed to assess the influence of the elastic properties of railway vehicle suspensions on the vehicle dynamic behaviour. To do this, 144 dynamic simulations were performed modifying, one at a time, the stiffness and damping coefficients, of the primary and secondary suspensions. 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 in future simulations without appreciably affecting the simulation results. In general terms, it was concluded that the highest influences were found for the longitudinal stiffness and the lateral stiffness of the primary suspension, and the lowest influences for the vertical stiffness and the vertical damping of the primary suspension, with the parameters of the secondary suspension showing intermediate influences between them.     

基于C-NCAP五星碰撞的主体铝制纯电动车正碰车身框架结构设计

论文针对纯电动车与传统燃油车在造型和布置上的差异化特点带来的车身正碰框架中的设计难点和痛点,提出了一套完整、可行且有效的主体铝制量产正碰车身框架结构设计方法,此方法专门针对纯电动布置进行实体建模和正碰工况下的拓补优化设计,制定正碰主体铝材料结构设计方案,以实现吸能效率的提升,保障乘员舱的安全可靠性,同时兼顾轻量化和共线...