液罐汽车稳态转弯行驶侧倾特性研究

本文研究液罐汽车在不满载并以稳定车速转弯行驶的条件下,因液体货物质心位置的变化而引起汽车侧倾角的变化规律。建立了有关力学模型与数学模型。研究结果表明在装载条件相同的条件下与运送固体货物汽车比较,液罐汽车的侧倾稳定性变坏;加设纵向隔板对侧倾稳定性有改善作用。     

解新汽车底盘检修及车轮定位常见问题（二）

（1）转向角：车辆在转弯时，前轮所能转过的最大转角为转向角。如图4所示。当车辆直线行驶时各车轮必需傈持平行一致向前．否则会造成轮胎磨损。车辆转弯时．四个车轮需围绕着同一圆心转弯才能将轮胎横向磨擦减至最小。此圆心与车轮的距离为转弯半径。由于内外侧车轮转弯半径不同．外侧车轮的转向角需小于内侧车轮。     

轮胎垂直载荷变化对大客车高速操纵稳定性影响的模拟分析

针对大客车质心高，抗侧倾能力弱，轴荷转移大等特点，研究分析了弯道行驶时垂直载荷变化对高速操纵稳定性的影响。建立了四轮五度大客车操稳性模型，对高速弯道行驶的大客车在遭遇不平路面时的操稳性进行了模拟分析，通过不同车速下行驶轨迹的比较，判明了垂直载荷变化对高速行驶稳定性的危害。考察分析了行驶速度，质心高度，行驶弯道半径等，对动态垂直载荷作用下的高速车辆行驶稳定性的影响。     

转弯ABC

转弯技巧:①摩托车进入弯道前的直线行驶部分时要充分减速。②判断确认转弯半径以决定转弯中的安全车速。③一般采用人体与车体一同倾斜的姿式。④转弯中既要保持左右平衡还要注意视野开阔。     

油罐车转弯横向稳定性的计算分析

油罐车平地急转弯和坡上转弯是容易引起横向翻倾的危险工况。由于油罐留有扩大容量和油液的流动性，转弯时油液质心偏移，导致横向稳定性减弱，本文分析并推导了具有椭圆截面罐体的油罐车转弯时的横向翻倾临界坡度角和转向加速度的计算公式，介绍了横向稳定特性曲线的绘制方法，并给出了计算实例。     

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。     

基于Matlab的半挂汽车列车侧倾稳定性分析

针对重型半挂汽车列车侧倾稳定性问题,在Matlab/simulink中建立了重型半挂汽车列车的数学模型及动力学仿真模型,并进行了转向盘阶跃转向输入下的牵引车驱动轴横向载荷转移仿真分析.仿真结果表明,牵引车驱动轴为侧倾稳定性危险车轴.通过分析不同车速和车辆结构参数时牵引车驱动轴载荷转移的变化情况,得到重型半挂汽车列车侧倾稳定性与车辆主要结构参数及不同车速间的关系.     

纵向质心位置对中置轴挂车的横向稳定性影响

为提高中置轴挂车的横向稳定性,根据TruckSim软件构建卡车-中置轴挂车模型,包括轮胎模型、载荷模型、道路模型,进行整车在空载和满载下的双移线工况仿真分析。根据各个状态变量的变化趋势,得知中置轴挂车是引起整车失稳的主要因素,并得到侧倾角速度和质心侧偏角对评价中置轴挂车质心位置变化时的稳定性更为有效的结论。通过改变中置轴挂车的纵向质心位置,即质心前移、质心不变、质心后移的对比分析,得到质心前移0.2 m时,是整车发生侧翻失稳的临界条件。中置轴挂车满载时的纵向质心位置与其车轴距离在前移0.45 m,后移0.2 m的范围内时,可保证整车在平直路面上稳定行驶。该研究可为中置轴挂车的安全运输提供参考。     

弯道行车注意啥

弯道,按其道路情况可分为平曲弯线道(即平路转弯)、竖曲线弯道(即上下坡转弯)。汽车要安全、平稳地通过弯道,就要处理好两个问题:一是合理地选择车辆行驶路线,以保证行驶平稳;二是尽量选择较大的转弯半径,合理的控制好行车速度,使离心力降到最小。 平路转弯 汽车平路行驶时,由于道路阻力小,较易提高行驶速度,在运行速度较高时转弯会产生较大的离心力,急转弯就会产生更     

城市道路交叉口右转弯车速影响因素研究

针对右转交通空间设计缺乏定量依据的问题,对右转交通环境各要素相关关系以及右转交通空间设计不合理引起的交通问题进行研究,以右转交通环境为研究对象进行数据采集,并对有效数据进行统计分析,提出路缘石转弯半径与右转弯车速之间的数量关系,并对道路因素及非道路因素与右转弯车速之间的关系进行多元回归分析,结果表明:各因素中右转弯半径、有无人行过街、相交道路设计车速差3个因素可解释右转弯车速68.4%的变差;对于右转弯设计车速、右转弯半径选取以及路内停车设计等提出若干精细化交通设计建议.     

Numerical Simulation of Vehicle Behavior during Straight Line Keeping on Undulating Road Surfaces

Numerical design of vehicles having optimal straight line stability on undulating road surfaces requires an accurate vehicle model based on knowledge of the relevant phenomena. Therefore, vehicle behavior on undulating straight roads has been analyzed and modeled. Measurements on a flat road surface have shown that the dedicated vehicle model yields accurate simulation results of the steering response to medium steering wheel angle inputs. In addition, the model has been validated by measuring two vehicle responses during normal driving on an undulating straight road: viz. the responses to the small steering wheel angle input and to the input by the global inclination of the road surface.     

Numerical Simulation of Vehicle Behavior during Straight Line Keeping on Undulating Road Surfaces

SUMMARY

Numerical design of vehicles having optimal straight line stability on undulating road surfaces requires an accurate vehicle model based on knowledge of the relevant phenomena. Therefore, vehicle behavior on undulating straight roads has been analyzed and modeled. Measurements on a flat road surface have shown that the dedicated vehicle model yields accurate simulation results of the steering response to medium steering wheel angle inputs. In addition, the model has been validated by measuring two vehicle responses during normal driving on an undulating straight road: viz. the responses to the small steering wheel angle input and to the input by the global inclination of the road surface.     

基于车辆稳定性的改扩建高速公路横坡方案安全性评价研究

针对改扩建高速公路单侧加宽方案老路利用时可能存在的行车稳定性问题,应用基于车辆动力学的建模仿真方法,采用联合仿真技术,在Carsim/Trucksim仿真软件中得到车辆在横坡组合路段行驶过程中车轮的垂直载荷与车辆侧向加速度;在Simulink中计算车辆的横向载荷转移率和侧向加速度;通过上述指标分析车辆横向侧翻和侧滑稳定性,判断车辆在改扩建公路横坡组合路段上的行驶稳定性;联合仿真结果表明,车辆在横向坡度为2%和1.5%、换道路长为120 m和80 m的横坡组合路段上行驶均具有良好的横向稳定性;该方法可用于其他道路和驾驶行为的车辆稳定性分析.      

Vehicle sideslip estimation and compensation for banked road

The sideslip driving status is of fundamental importance to the stability of a vehicle. This paper presents a practical vehicle sideslip driving status estimation method that uses ESP (electronic stability program) sensors. ESP sensors such as wheel speed, lateral acceleration, yaw rate and steering wheel angle sensors are used to determine the sideslip driving status and distinguish a banked road. This estimation algorithm contains front-rear sideslip and banked road detection methods. The proposed sideslip estimation algorithm was designed to use the analytical redundancy of these sensors and Lagrange interpolation methods. The performance and effectiveness of the proposed estimation and compensation algorithm were investigated using vehicle tests. This paper presents the results of two cases that were used for the experimental verification: a curved flat road and banked road.     

Roll Plane Analysis of Articulated Tank Vehicles During Steady Turning

The rollover immunity levels of articulated tank vehicles with partial loads are investigated. A static roll plane model of the articulated vehicle employing partially filled cylindrical tank is developed. The vertical and lateral translation of the liquid cargo due to vehicle roll angle and lateral acceleration, encountered during steady turning, are evaluated. The roll moments arising from vertical and lateral translation of the liquid cargo are determined and incorporated in the roll plane model of the vehicle. The adverse influence of the unique interactions of the liquid within the tank vehicle, on the rollover limit of the articulated vehicle is demonstrated. The influence of compartmenting of the tank on the steady turning roll response of the vehicle is analyzed, and an optimal order of unloading the compartmented tank is discussed.     

基于MPC的独立驱动电动汽车稳定性集成控制

针对独立驱动电动汽车在高附着系数路面高速急转时易发生侧翻事故,在低附着系数路面急转易发生侧滑失稳事故,且单一控制器在不同附着系数路面适应性较差等问题,根据独立驱动电动汽车特点设计了基于分层式结构的稳定性集成控制器。建立了整车动力学模型,并进行了车辆状态参数估计;设计了稳定性集成控制器的控制策略,对车辆的侧倾、横向稳定性状态判定条件和协调策略的制定进行了研究,分别设计了侧倾稳定性控制器和横向稳定性控制器;设置了路面附着系数0.9到0.2的对接路面仿真工况,并在此工况下对所设计的控制器的控制性能进行了仿真测试。结果表明,所设计的稳定性集成控制器相比于单一控制器具有更好的适应性,可有效降低车辆高速行驶过程中的横向载荷转移系数、质心侧偏角等状态量,提高车辆行驶的稳定性和安全性。     

Roll Plane Analysis of Articulated Tank Vehicles During Steady Turning

SUMMARY

The rollover immunity levels of articulated tank vehicles with partial loads are investigated. A static roll plane model of the articulated vehicle employing partially filled cylindrical tank is developed. The vertical and lateral translation of the liquid cargo due to vehicle roll angle and lateral acceleration, encountered during steady turning, are evaluated. The roll moments arising from vertical and lateral translation of the liquid cargo are determined and incorporated in the roll plane model of the vehicle. The adverse influence of the unique interactions of the liquid within the tank vehicle, on the rollover limit of the articulated vehicle is demonstrated. The influence of compartmenting of the tank on the steady turning roll response of the vehicle is analyzed, and an optimal order of unloading the compartmented tank is discussed.     

汽车操纵稳定性的中间位置转向试验

操纵稳定性中间位置转向试验最初是由美国德尔福公司制定的，是汽车在高速行驶条件下操纵性和稳定性的重要评价方法。通过试验的原始数据可以绘制出转向盘转角与侧向加速度、转向盘力矩与侧向加速度、转向盘力矩与转向盘转角等多条特性曲线，以作为不同的评价指标。以CAll41载货汽车作为实例分析，发现该车转向干摩擦偏大，转向刚度偏低，高速行驶时的非线性路感不够理想。     

Stationar- und Ubergangsverhalten von Sattel- und Lasttugen bei der Kreisfahrt: Lineare Berechnungen

Steady and Transient Turning of Tractor-Semitrailer and Truck-Trailer Combinations: A Linear Analysis

A simplified analysis is made of the yaw stability and control of the two types of the commercial vehicle combinations (tractor-semitrailer, truck-trailer) at a constant forward velocity during steady and transient turning. The combined vehicle is treated as a linear dynamic system (Fig. 2). The steer angle at the front wheels of the tractor (or truck) and the steady-state responses if the road verhicle train (yaw rate, articulation angles and sideslip angle) are calculated (Equations 18 to 25). Exploratory calculations are performed to determine the influence of the cornering stiffness of the tires for the two types of the vehicle combinations upon the steady-state responses (Figs. 7 to 10). For a linear simplified model of articulated vehicle the steady-state turning behaviour is stable also under conditions of rather high driving speed (70 km/h). A simplified analysis of the transient turning behaviour of the two types of road trains has shown the tractor-semitrailer to preserve stability even under driving speeds exceeding 70 km/h (Fig. 13), whereas the truck-trailer combinations appear to become oscillatory unstable if the driving speed rises above the 60 km/h margin (Fig. 14).     

左转圆曲线处避险车道流出角与引道设置

为了给设置于左转圆曲线处的避险车道流出角与引道长度设置提供参考,针对山区高速公路广泛采用的9.0 m宽制动床避险车道,考虑左转圆曲线半径和驶入速度的影响,进行了不同流出角度与引道长度的驾驶仿真试验研究。采用UC-win Road 9.0驾驶仿真平台,获取了不同场景下16名男性B照驾驶人由主线驶入紧急避险车道过程中的车辆运行特征数据。采用拟合回归的方法,分析了圆曲线半径和驶入速度对方向调整时间、最小转向半径、方向盘转角幅值、方向盘转角频率的影响,建立了各指标与圆曲线半径的定量回归关系模型,并对比了主线为直线时的试验结果。采用二阶聚类的方法对不同圆曲线半径条件下的引道与流出角度的设置水平进行分类,获取了适宜设置避险车道的初步条件。根据车辆的行驶稳定性,确定了左转圆曲线处避险车道流出角与引道的设计标准。研究结果表明：左转圆曲线处避险车道的流出角受圆曲线半径的影响,引道长度受圆曲线半径与驶入速度的影响;主线半径1 000 m及以上,流出角0°~5°,引道为6 s设计行程,流出角5°~10°,引道为9 s设计行程;条件困难时,紧急避险车道可设置于半径600~1 000 m的曲线处,流出角0°~5°,引道为9 s设计行程,流出角5°~15°,引道为12 s设计行程。