某重型货车驾驶室侧翻碰撞仿真分析

通过对比分析ECE R29碰撞法规、瑞典国家碰撞法规和OICA修改意见,参考ECE R66法规中侧翻安全性的试验方法,建立了某款重型货车驾驶室有限元分析模型,并进行计算机模拟侧翻试验,验证其侧翻安全性并找出结构的薄弱环节.根据侧翻仿真分析试验结果提出了结构改进建议,以减轻在侧翻事故中货车驾驶室内乘员所受到的伤害.     

基于ADAMS/Car的车辆侧翻风险因素研究

为了研究车辆侧翻风险因素对车辆侧翻的影响程度,运用ADAMS/Car软件建立了某轿车的多体动力学模型,基于仿真分析的方法进行了鱼钩转向侧翻试验设计,并选取横向载荷转移率作为度量车辆侧翻风险的指标.通过正交试验的方法,研究了路面摩擦系数、车辆行驶速度、方向盘角速度以及质心高度对车辆侧翻的影响程度.结果表明,在给定的水平下影响车辆侧翻的因素按其影响的强弱程度依次为:车辆行驶速度、路面摩擦系数、质心高度、方向盘角速度,其中车辆行驶速度对车辆的侧翻具有显著性影响.     

多分辨率视角下危险品事故风险评估方法

从区域宏观风险与路径事故风险的双重视角,科学评估危险品事故风险,对于危险品运输行业管理与事故应急管理具有重要价值.通过建立风险特征-风险影响因子-事故风险的分析框架,充分考虑单位面积人口数对地区事故风险的影响以及路径总长度和运输总时长对路径事故风险的影响,建立地区事故风险和路径事故风险识别方法,从危险品数量、事故风险2个维度构建危险品事故风险的多分辨率评估模型;利用电子运单数据结合空间分析方法,计算危险品的县域事故风险及路径事故风险.运用某地危险品公路运输电子运单数据进行实例评估,验证结果表明,该方法可评估多种视角下危险品事故风险,识别出高事故风险县域和路径,并具有与专项运输规划、突发事件应急预案等制度相结合的潜力.      

侧翻之烦

车辆侧翻,指车辆主体或总体向行驶或停放方向左侧或右侧倾倒甚至翻倒的一种事故现象.美国高速公路交通安全管理局统计数据表明,在车辆事故中,侧翻的危害程度仅次于碰撞事故居第2位.近几年来,侧翻之烦作为重要的安全问题,受到普遍关注.侧翻的传统静态稳定因素包括重心高度及轮距宽度,而动态稳定因素不仅包括静态稳定因素,还包括簧载质量差异、重心横向位置、悬架侧倾刚度、车辆侧倾臂长、轮胎及悬架变形等结构参数,以及车速、转弯半径等操纵参数的影响.本文从重力偏心、离心力离心、力偶矩分心等3个侧翻根源人手分析,提出预防和解决侧翻之烦的系列对策.     

客车预警防侧翻控制研究

客车车辆重心高、轮距窄,在紧急避让或高速超车易发生侧翻事故。建立三自由度名义模型,联立TruckSim非线性整车模型设计了基于横向动态载荷转移率预警系统和防侧翻系统,利用角阶跃工况联合仿真对设计系统进行验证。仿真结果表明:基于模糊PID控制能够有效改善客车行驶稳定性,降低客车侧翻风险。     

叉车无革行驶侧翻的技术探讨

1课题的提出 2004年我国共计生产了6．5万台乘驾式叉车，除了个别的外资企业在其说明书中提及了驾驶员如何防止叉车无载行驶侧翻，以及侧翻发生后如何正确操作外，其它生产商均未告知使用者。国内对这方面的研究统计也很少。然而，在国内叉车的使用中发生无载行驶侧翻的频率是很高的，据报道：一个杂货码头的某公司共有100多台叉车，在1989至1990年两年内发生了6宗叉车侧翻事故。国外对侧翻事故的统计报道：侧翻事故占事故总数的21％。     

汽车侧翻分析及试验检测

汽车在行驶中侧翻是最为严重威胁乘员安全的一种事故,其与汽车稳定性和人员操纵密切相关。造成汽车侧翻的因素很多,为了明晰汽车发生侧翻的原因,对汽车发生侧翻和对汽车静态稳定性检测进行了分析阐述,以便明晰防范汽车侧翻的方法。     

侧翻试验台事故分析研究

针对侧翻试验台在试验过程中出现的倾翻事故,分析了事故发生的原因,提出了侧翻试验台整改的恢复方案,为汽车侧翻安全稳定性的检测工作提供了有利的参考。     

叉车侧翻原因及预防指南

<正>1叉车侧翻在国内叉车的使用中发生行驶侧翻的频率是很高的,例如:一个杂货码头的某公司共有100多台叉车,在某两年内发生6宗叉车侧翻事故。侧翻是叉车在装卸中属多发事故,客观原因是由于是叉车转弯时的离心力的作用,以及叉车在侧向斜坡上行驶时由于重力沿斜坡方向的分力的作用等;主要原因则是司机没有严格按照规章制度的要求去做。国外对侧翻事故的统计报道,侧翻占事故总数的21%。本文主要探讨叉车的侧翻原因,以及当     

重型汽车侧翻因素分析

重型汽车由于结构尺寸大、质心较高、装载量大等因素,导致其侧倾稳定性相对较差,容易发生侧翻事故。本文从理论的角度阐述了重型汽车发生侧翻的条件,以重型汽车本身的构造分析了侧翻原因,提出了其应对侧倾的相应措施,为重型汽车防侧翻装置的设计及研究提供一定的技术支持。     

Rollover risk prediction of heavy vehicles by reliability index and empirical modelling

This paper focuses on a combination of a reliability-based approach and an empirical modelling approach for rollover risk assessment of heavy vehicles. A reliability-based warning system is developed to alert the driver to a potential rollover before entering into a bend. The idea behind the proposed methodology is to estimate the rollover risk by the probability that the vehicle load transfer ratio (LTR) exceeds a critical threshold. Accordingly, a so-called reliability index may be used as a measure to assess the vehicle safe functioning. In the reliability method, computing the maximum of LTR requires to predict the vehicle dynamics over the bend which can be in some cases an intractable problem or time-consuming. With the aim of improving the reliability computation time, an empirical model is developed to substitute the vehicle dynamics and rollover models. This is done by using the SVM (Support Vector Machines) algorithm. The preliminary obtained results demonstrate the effectiveness of the proposed approach.     

Stability and optimised H∞ control of tripped and untripped vehicle rollover

Vehicle rollover is a serious traffic accident. In order to accurately evaluate the possibility of untripped and some special tripped vehicle rollovers, and to prevent vehicle rollover under unpredictable variations of parameters and harsh driving conditions, a new rollover index and an anti-roll control strategy are proposed in this paper. Taking deflections of steering and suspension induced by the roll at the axles into consideration, a six degrees of freedom dynamic model is established, including lateral, yaw, roll, and vertical motions of sprung and unsprung masses. From the vehicle dynamics theory, a new rollover index is developed to predict vehicle rollover risk under both untripped and special tripped situations. This new rollover index is validated by Carsim simulations. In addition, an H-infinity controller with electro hydraulic brake system is optimised by genetic algorithm to improve the anti-rollover performance of the vehicle. The stability and robustness of the active rollover prevention control system are analysed by some numerical simulations. The results show that the control system can improve the critical speed of vehicle rollover obviously, and has a good robustness for variations in the number of passengers and longitude position of the centre of gravity.     

Design of a rollover index-based vehicle stability control scheme

This paper presents a rollover index (RI)-based vehicle stability control (VSC) scheme. A rollover index, which indicates an impending rollover, is developed by a roll dynamics phase plane analysis. A model-based roll estimator is designed to estimate the roll angle and roll rate of the vehicle body with lateral acceleration, yaw rate, steering angle and vehicle velocity measurements. The rollover index is computed using an estimated roll angle, estimated roll rate, measured lateral acceleration and time-to-wheel lift. A differential braking control law is designed using a direct yaw control method. The VSC threshold is determined from the rollover index. The effectiveness of the RI, the performance of the estimator and the control scheme are investigated via simulations using a validated vehicle simulator. It is shown that the proposed RI can be a good measure of the danger of rollover and the proposed RI-based VSC scheme can reduce the risk of a rollover.     

基于制动与悬架系统的车辆主动侧翻控制的研究

为提高车辆抗侧翻能力,建立了10自由度整车侧翻动力学模型,应用车辆动力学和轮胎力耦合特性,提出了一种基于差动制动和半主动悬架协同工作的车辆主动抗侧翻控制策略。通过对制动力矩的差动调节和半主动悬架阻尼力的适时匹配,实现对车辆侧翻的有效控制。根据子系统运动特性,设计了制动系统基于滑移率的积分滑模控制器和悬架系统灰模糊控制器。分别对制动、悬架控制及综合控制进行的鱼钩试验仿真结果表明,综合控制策略可有效降低危险时域车辆的侧倾角,相对于单一系统控制进一步提高了车辆抗侧翻能力。     

Effect of vertical and lateral coupling between tyre and road on vehicle rollover

The vehicle stability involves many aspects, such as the anti-rollover stability in extreme steering operations and the vehicle lateral stability in normal steering operations. The relationships between vehicle stabilities in extreme and normal circumstances obtain less attention according to the present research works. In this paper, the coupling interactions between vehicle anti-rollover and lateral stability, as well as the effect of road excitation, are taken into account on the vehicle rollover analysis. The results in this paper indicate that some parameters influence the different vehicle stabilities diversely or even contradictorily. And it has been found that there are contradictions between the vehicle rollover mitigation performance and the lateral stability. The direct cause for the contradiction is the lateral coupling between tyres and road. Tyres with high adhesion capacity imply that the vehicle possesses a high performance ability to keep driving direction, whereas the rollover risk of this vehicle increases due to the greater lateral force that tyres can provide. Furthermore, these contradictions are intensified indirectly by the vertical coupling between tyres and road. The excitation from road not only deteriorates the tyres’ adhesive condition, but also has a considerable effect on the rollover in some cases.     

Stability measurement of high-speed vehicles

Vehicle rollover represents a significant percentage of single-vehicle accidents and accounts for over 9000 fatalities and over 200,000 non-fatal injuries each year. Previous research has yielded rollover stability control systems that are effective in on-road conditions. Accident statistics show, however, that over 90% of rollovers involve road departure, during which a vehicle may encounter sloped and rough terrain while travelling at high speed. A critical element of most rollover stability control systems is a metric that monitors a vehicle's nearness to rollover. Most metrics, however, are designed for use on flat, level surfaces characteristic of on-road terrain. In this paper, a new stability metric, termed the stability moment, is proposed that is accurate on terrain surfaces with arbitrary geometry, which allows it to be used in road departure scenarios. The metric is based on an estimate of the distribution of wheel–terrain contact forces. The metric can be calculated on line in real time, using only practical, low-cost sensors. The metric is compared in simulations and experimental studies to existing stability metrics and is shown to exhibit superior performance, particularly in off-road conditions.     

多用途乘用车侧翻稳定性能动态测试方法研究

对比分析了国内外车辆侧翻稳定性相关的标准法规的基本情况。研究了车辆发生侧翻的类型和机理,基于侧向加速度判断车辆侧翻状态的方法,通过整车道路试验对比了正弦停滞试验和鱼钩试验诱导车辆发生侧翻的效果,初步探讨了多用途乘用车侧翻稳定性动态测试方法和评价指标,为国内车辆侧翻稳定系统的开发和测评标准的制定提供了参考。     

Path-following in model predictive rollover prevention using front steering and braking

In this paper vehicle path-following in the presence of rollover risk is investigated. Vehicles with high centre of mass are prone to roll instability. Untripped rollover risk is increased in high centre of gravity vehicles and high-friction road condition. Researches introduce strategies to handle the short-duration rollover condition. In these researches, however, trajectory tracking is affected and not thoroughly investigated. This paper puts stress on tracking error from rollover prevention. A lower level model predictive front steering controller is adopted to deal with rollover and tracking error as a priority sequence. A brake control is included in lower level controller which directly obeys an upper level controller (ULC) command. The ULC manages vehicle speed regarding primarily tracking error. Simulation results show that the proposed control framework maintains roll stability while tracking error is confined to predefined error limit.     

Contour line of load transfer ratio for vehicle rollover prediction

For vehicle rollover control systems, an accurate and predictive rollover index is necessary for a precise rollover threat detection and rollover prevention. In this paper, the contour line of load transfer ratio (CL-LTR) and the CL-LTR-based vehicle rollover index (CLRI) are proposed, describing LTR threshold and LTR change rate precisely, providing an accurate prediction of vehicle rollover threat. In detail, the CL-LTR is proposed via the roll dynamics phase plane analysis, and its analytical solution of one-degree-of-freedom vehicle roll model and extension for full vehicle are derived. Moreover, the predictive CLRI is proposed and evaluated via vehicle dynamics study. The results demonstrate that vehicle rollover threat is predicted accurately based on the CLRI, which shows benefits for the vehicle rollover prediction and stability control.     

Vehicle lift-off modelling and a new rollover detection criterion

The modelling and development of a general criterion for the prediction of rollover threshold is the main purpose of this work. Vehicle dynamics models after the wheels lift-off and when the vehicle moves on the two wheels are derived and the governing equations are used to develop the rollover threshold. These models include the properties of the suspension and steering systems. In order to study the stability of motion, the steady-state solutions of the equations of motion are carried out. Based on the stability analyses, a new relation is obtained for the rollover threshold in terms of measurable response parameters. The presented criterion predicts the best time for the prevention of the vehicle rollover by applying a correcting moment. It is shown that the introduced threshold of vehicle rollover is a proper state of vehicle motion that is best for stabilising the vehicle with a low energy requirement.