多轴转向汽车的优化设计

1前言 近年来,随着重型车辆的飞速发展,用户对它的性能要求已越来越高.由于转向性能直接影响整车的机动性、灵活性、操纵稳定性和使用经济性,因此对重型车辆的转向系统提出了更高的要求.多轴转向汽车的转向系统的设计需要优化转向系结构来实现最佳的转向过程(转向时所有的转向轮都处于纯滚动状态或者只有极小的滑移),达到最小的轮胎磨损,减小转弯半径和转向阻力矩的目的.     

飞机牵引车多功能转向特性分析

论述了飞机牵引车多功能转向的特点；提出了转向功能切换时，轮胎磨损加剧的问题；提出了以车轴的轴偏角作为评价轮胎磨损的指标，并对某具体转向机构进行了计算分析。     

重型汽车双前桥转向系统分析优化研究

<正>目前市场上双前桥重型汽车普遍存在轮胎磨损的问题,特别是二桥轮胎磨损较为明显,影响客户正常工作的同时也造成了一定经济损失。经理论分析,双转向车     

多轴转向车辆动态转向控制策略研究

为了提高多轴转向车辆的转向安全性和操纵稳定性,对基于零侧偏角比例控制策略的多轴转向车辆的普适动力学模型进行了推导,并利用ADAMS/View和Easy5软件建立了三轴转向车辆的机电液一体化联合仿真模型.仿真分析了不同工况下,各轴转向油缸受力的变化规律、车轮转角的变化规律、质心侧向加速度和横摆角速度的变化规律等.最后,针对质心零侧偏角比例控制的缺点,提出了一种系数改进法,该方法对提高多轴转向车辆高速的灵活性和稳定性具有重要的意义.     

基于ADAMS的双前桥重型汽车转向运动学研究

利用某公司提供的实车数据建立了基于ADAMS的双前桥重型汽车的转向机构和悬架机构模型，运用该模型进行转向运动学关系虚拟仿真．并与理论数据进行比较。同时并对该车的悬架干涉情况进行仿真分析。其分析结果为该车转向系的改进设计提供了理论依据。     

转向系统特性参数对中心转向区车辆性能的影响

在总结中心转向区性能评价标准的基础上,建立了较完善的转向系统模型,将其嵌入到整车模型中,研究了转向系统参数对中心转向区性能的影响.通过中心转向区转向试验与仿真分析数据可知,转向系统传动比、干摩擦、刚度等特性参数直接影响驾驶员的驾驶疲劳度、驾驶路感和车辆的转向灵敏性.     

重型汽车转向特性试验研究

驾驶员通过作用在转向盘上的力或使转向盘产生一定的角位移来控制汽车的转向运动,即驾驶员给汽车的转向指令可以分成两大类:力指令和角指令.由此,汽车对指令的反应特性也可以分成两大类力输入反应特性和角输入反应特性.可把回正性能看作一种力输入反应特性.通过对重型汽车回正性能试验结果的分析,本文初步探讨了重型汽车回正试验结果的评价方式及其力输入反应频率特性.由于汽车在线性区内工作的几率远大于在非线性区内工作的几率,因此对汽车线性区内的转向特性应进行探入、细致的研究.本文所研究的重型汽车回正性能是汽车线性区内的回正性能,这样可以相对容易地获取试验结果和分析汽车力转向特性,从而获得收善重型汽车转向特性的途径.     

多轴转向载货车转向系基于最小半径的优化

建立了五轴汽车(10×8)二自由度模型,研究了多轴转向系统中各轮偏转角之间的关系对转向半径和稳态响应的影响,得出了五轴汽车转向半径的一般表达式,并对某型多轴车进行了基于最小转向半径的转角比例关系的优化.     

基于LuGre模型的轮胎原地转向模型

基于LuGre摩擦模型的轮胎原地转向模型可表达不同轮胎刚度和载荷、不同输入频率、不同摩擦特性等工况下的回正力矩随转动角的变化关系,适于进行轮胎模型相关实时仿真运算及控制系统研究.讨论了该模型的建立过程和模型参数对轮胎转向特性的影响,进行了参数的辨识及模型仿真计算与试验结果的对比,结果表明二者有较好的一致性.     

重型车辆多轴转向系统设计综述

综述了重型汽车多轴转向系统设计的现状、主要内容及方法,分析了目前我国存该领域研究所存在的主要问题,提出了基于整车底盘系统集成优化匹配平台的转向系统设计方法.以某8×4载货汽车双前桥转向系统为例,阐述了基于该方法的横拉杆设汁过程.结果表明,该设计方法能够充分发挥所集成的各优化分析软件的优势,实现各车型设计的高效率与自动化.     

Theory and experimental research on six-track steering vehicles

The structural characteristics and steering behaviour of a six-track vehicle are described in this paper. Kinematic analysis for skid steering of a six-track vehicle under steady-state conditions on firm ground is conducted, with the relationship between thrust force and speed instantaneous centre of the track–terrain interface taken into consideration. A mechanical model for steady steering of a six-track vehicle is also presented based on the kinematic analysis. In this model, the steering inaccuracy and efficiency are defined to evaluate steering performance. The steering performance of a six-track vehicle is numerically simulated to analyse the effect of the structural parameters and deflection angles on tracks. A virtual prototype model is established based on the multi-body dynamics software RecurDyn for steering simulation and the findings coincide well with theoretical results. The theory and the virtual prototype simulations presented are verified by a power test of a bucket-wheel excavator. The method for analysing the steering performance of a six-track vehicle proposed in this paper provides a basis for designing a six-track vehicle.     

基于驾驶人转向意图的双电机驱动电动汽车稳定性控制策略

为了使双电机驱动电动车在车辆稳定性控制过程中能够精确解读驾驶意图,使车辆实际行驶状态与驾驶意图期望的车辆行驶状态尽可能相符合,提出一种基于驾驶人意图辨识的稳定性控制策略.利用基于支持向量机递归特征消除(SVM-RFE)得到的特征参数构建基于长短期记忆(LSTM)模型的驾驶人转向意图辨识模型;基于转向意图识别结果,以方向...     

Tire wear estimation based on nonlinear lateral dynamic of multi-axle steering vehicle

This paper presents a novel nonlinear dynamic model of a multi-axle steering vehicle to estimate the lateral wear amount of tires. Firstly, a 3DOF nonlinear vehicle dynamic model is developed, including dynamic models of the hydropneumatic suspension, tire, steering system and toe angle. The tire lateral wear model is then built and integrated into the developed vehicle model. Based on the comparison of experimental and simulation results, the nonlinear model is proved to be better than a linear model for the tire wear calculation. In addition, the effects of different initial toe angles on tire wear are analyzed. As simulation results shown, the impact of the dynamic toe angle on the tire wear is significant. The tire wear amount will be much larger than that caused by normal wear if the initial toe angle increases to 1° - 1.5°. The results also suggest that the proposed nonlinear model is of great importance in the design and optimazation of vehicle parameters in order to reduce the tire wear.     

基于车路系统的事故现场轮胎印迹强度参数化研究

为明确事故现场可视轮胎印迹强度与车辆动力学特性、轮胎橡胶磨损特征及道路表面灰度之间的关联特性,提出基于车路耦合的事故现场轮胎印迹强度参数化研究方法。通过结合动态滑动摩擦因数模型及轮胎非线性模型,建立车辆路面9 DOF非线性系统动力学模型,运用VBOX惯性测量技术验证模型的有效性。运用胎面磨损能量模型,从车路系统角度确定车辆、轮胎和路面特性对轮胎全局摩擦力及胎面磨损特性的影响。结合印迹强度特征模型提出轮胎印迹强度参数研究方法,选取不同制动、转向角工况及3组路面、胎面特性对轮胎路面接地力学特性、胎面橡胶磨损量、可视轮胎印迹特征进行仿真分析。结果表明：印迹强度仅与全局摩擦力大小有关,与轮胎路面滑移方向无关;滑移工况下胎面橡胶磨损量随着全局摩擦力和滑移速度的增大而增大,而印迹强度变化不明显;制动力矩和道路表面灰度对产生可视轮胎印迹起决定作用,转向角主要影响不规则可视轮胎印迹的产生;前轮轮胎最先出现可视印迹,且可视印迹长度和强度均高于后轮轮胎;采取可视印迹起点作为事故车辆速度判定具有一定的误差,应根据具体情况进行具体分析;研究成果能够为基于可视轮胎印迹的交通事故重建提供理论基础。     

不同转向模式的多轴转向车辆性能分析

为解决重型车辆转向时的低速机动性和高速稳定性的问题,提出了多轴动态转向技术,并以三轴车辆为研究对象进行分析。首先建立多轴转向的二自由度车辆模型以及运动微分方程,为提高车辆的稳定性,以零质心侧偏角为目标,推导各轴间的转角比例系数及有关的状态空间矩阵、传递函数,使用MATLAB软件对不同转向模式下的操纵稳定性进行了稳态响应、瞬态响应以及频域响应的仿真。通过分析比较,说明采用多轴动态转向技术,车辆在转向时具有低速机动性高、高速稳定性好的特点。     

Modelling and control of a new differential steering concept

This paper presents a new steer-by-wire concept using an all-wheel drive vehicle layout with in-wheel motors while completely omitting the application of any dedicated steering device. Steering is based on the so-called differential steering principle which generates the necessary steering moment about the kingpins by a traction force difference between left and right sides of the vehicle. In order to investigate the behaviour of the vehicle and to design the underlying control algorithms, a planar vehicle model is presented, where the vehicle is described as constrained non-holonomic system requiring a special treatment. A state feedback linear controller for controlling of the lateral dynamics of the vehicle at higher speeds and a simple PI angle controller for low-speed manoeuvring are developed. The resulting behaviour of the system is investigated by various simulation experiments demonstrating a comparable steering performance of the new steering concept as that of conventional passenger cars.     

电动客车稳态转向特性仿真研究

利用虚拟样机分析软件ADAMS建立了整车多体动力学模型,并进行了仿真分析。研究了由电池布置带来的前后轴载荷变化(整车质心位置变化)和横向稳定杆对转向性能的影响。结果显示,整车在空载和满载时均为不足转向;后轴载荷比例增加对稳态转向不利;加装横向稳定杆可以大大改善车厢侧倾,对稳态转向有一定改善。     

Desired yaw rate and steering control method during cornering for a six-wheeled vehicle

This paper proposes a steering control method based on optimal control theory to improve the maneuverability of a six-wheeled vehicle during cornering. The six-wheeled vehicle is believed to have better performance than a four-wheeled vehicle in terms of its capability for crossing obstacles, off-road maneuvering and fail-safe handling when one or two of the tires are punctured. Although many methods to improve the four-wheeled vehicle’s lateral stability have been studied and developed, there have only been a few studies on the six-wheeled vehicle’s lateral stability. Some studies of the six-wheeled vehicle have been reported recently, but they are related to the desired yaw rate of a four-wheeled vehicle to control the six-wheeled vehicle’s maneuvering during corning. In this paper, the sideslip angle and yaw rate are controlled to improve the maneuverability during cornering by independent control of the steering angles of the six wheels. The desired yaw rate that is suitable for a six-wheeled vehicle is proposed as a control target. In addition, a scaled-down vehicle with six drive motors and six steering motors that can be controlled independently is designed. The performance of the proposed control methods is verified using a full model vehicle simulation and scaled-down vehicle experiment.     

商用车双转向桥中间杆系优化设计

商用车双转向桥包含两个独立的转向梯形机构,它们之间的运动是通过中间杆系来传递的.在设计双转向桥转向系统时,为了避免转向桥轮胎异常磨损,需要两个转向桥的车轮转角协调变化.提出了一种对现有双转向桥中间杆系优化设计的方法,可协调车辆第一、第二转向桥的转角关系,避免了横向滑移导致的双前桥车轮转向时造成的轮胎异常磨损.     

Analysis of Influence of Design Parameters on Steered Wheels Shimmy of Heavy Vehicles

In choosing the steering system parameters the tendency is towards the minimization of kinematic errors that appear during turning. For that developed procedures exist that take into account also the influence of kinematic of the suspension system on kinematic parameters of vehicle turning. Besides that, maintenance tests have shown, that increased deflections of the suspension system lead to increased wear of tires of steered wheels. In this paper, a method is developed for minimization of steered wheel shimmy and its wear also during the straight-line drive of heavy vehicles. The procedure can also be used in the phase of designing the heavy vehicles.