液压互联悬架参数对其刚度和阻尼的影响

在车辆悬架强度设计问题的研究中,抗侧倾液压互联悬架系统的刚度和阻尼不仅与车辆的机械系统的参数相关,还与液压系统的参数相关.为了研究液压互联悬架系统参数对悬架等效刚度和阻尼的影响,建立了装有抗侧倾液压互联悬架的SUV车辆在侧倾平面内的频域振动半车模型,推导了系统的等效刚度和阻尼的表达式,得到了由系统参数求悬架等效刚度和阻尼的仿真分析方法,并分析了液压缸上下腔的面积、液压缸的直径、储能器的预充压力等参数对系统的等效刚度和阻尼的影响.结果表明抗侧倾液压互联悬架系统的液压元件参数改变对系统等效侧倾刚度及系统的等效阻尼的影响很大,但对系统的垂向等效刚度影响很小.仿真结果可以为液压互联悬架系统的刚度和阻尼设计提供理论依据.     

连通式油气悬架三轴重型车辆模型非线性动力学分析

建立了基于连通式油气悬架的三轴重型车辆模型,分别将路面不平度考虑为冲击激励、随机激励和正弦激励,分析了连通式油气悬架的非线性特性对三轴重型车辆振动特性的影响,并分析了连通式油气悬架的抗俯仰性能及抗侧倾性能;将路面不平度考虑为正弦激励,以路面不平度激励频率为参数,通过分叉图、波形图、相图以及庞加莱截面分析了正弦激励作用下三轴重型车辆的非线性动力学响应,仿真结果表明系统在不同激励条件下存在周期运动和混沌运动;连通式油气悬架对重型车辆具有较好的抗侧倾和俯仰特性.     

车辆动力学与控制研究进展

从车辆纵、横、垂向动力学三个方面,结合电动汽车、智能网联等热点问题,介绍了目前车辆动力学与控制领域的研究成果.车辆纵向动力学方面包括车辆传动系统换挡控制、制动系统的设计与控制以及车辆状态的参数估计;车辆横向动力学方面涉及车辆转向系统设计与横向稳定性控制;车辆垂向动力学方面包括悬架系统的优化设计与半/主动控制.专刊研究成果涉及车辆动力学与控制方向的多种问题,可为今后开展相关研究提供参考.     

双横臂独立悬架运动特性分析与优化

研究双横臂独立悬架性能优化问题,在车辆运动过程中,由于车轮与车身之间的相对位置发生变化,造成车轮定位参数的变动过大,加剧轮胎磨损,并降低悬架的性能.针对上述问题,通过对悬架系统简化处理,建立悬架运动学分析理论模型.为改进悬架性能,采用统一目标法,将多目标优化转化为单目标优化,实现在ADAMS/Insight中对悬架结构参数进行优化设计.利用ADAMS/Car软件建立了双横臂独立悬架动力学仿真模型并进行仿真,结果表明优化后车轮定位参数和轮距的变化量均减小,更趋于合理的取值范围,悬架性能得到改善.     

刚柔耦合特种车辆越障行驶动力学分析及悬架优化

考虑炮管柔性,建立了某轮式特种车辆的刚柔耦合整车动力学模型,并与刚性车辆模型进行对比,分析了刚柔耦合建模对炮管响应的影响;然后计算了该车通过垂直凸台障碍路面的极限高度,分析了刚柔耦合特种车辆通过凸台障碍路面时的动力学特性.以车辆质心垂向加速度为优化目标,悬架刚度和阻尼为优化参数,对悬架进行优化.结果表明,炮管的弹性变形对炮口垂向和水平方向线位移、线速度和角速度的影响显著,建模中有必要考虑炮管柔性,以更准确地计算车辆响应;低速行驶、小的凸台高度,对减小车辆振动有利,在各种工况参数下炮管的垂向振动都比车体振动剧烈;单侧轮通过障碍可以减小路面对整车的冲击,双侧轮通过障碍可以提高车辆稳定性并减小炮管振动;悬架优化后整车和炮管的垂向加速度都明显降低,车辆平顺性得到有效改善.     

基于Adams/Car的汽车前悬架仿真分析及优化设计

针对某车型的麦弗逊前悬架系统,用车辆多体动力学仿真软件Adams/Car建立该悬架的虚拟样机模型,对其进行双轮同向跳动激振仿真分析,并综合评价该悬架的车轮定位参数、主销后倾拖距和转向角随轮跳的响应特性.在仿真分析的基础上,针对不合理的结构设计参数,利用Adams/Insight模块进行基于设计变量灵敏度分析的优化设计.优化后的悬架参数能很好地满足设计要求,从而达到提高该悬架系统整体性能的目的.     

基于ADAMS的非独立悬架-转向系统运动学仿真

以多体系统动力学理论为基础,利用ADAMS软件,建立了一类四轮驱动车辆非独立前悬架及转向系统的参数化虚拟样机;通过柔度矩阵的方法对其进行弹性运动学仿真分析,考察对车辆操纵稳定性、平顺性影响很大的转向轮定位参数的运行特性,从而为汽车的设计和制造提供理论依据。     

两种车辆悬架系统的建模与控制仿真

车辆悬架系统作为汽车的一个重要组成部分,其性能好坏会影响到车辆的平顺性与稳定性。以1/4车辆模型为例,从被动悬架到主动悬架,将车辆悬架系统动力学原理与MATLAB仿真软件相结合,即首先利用动力学理论建立其数学模型,然后在仿真软件中建立其相对应的模型进而动态仿真,最后对比结果。实验结果表明,在车轮动载荷大致相同的条件下,设计的主动悬架有效地降低了车体的垂直加速度,与被动悬架相比,优化了约17%,提高了车辆在行驶过程的平顺性和驾驶的稳定性。     

路面激扰与电磁激扰下电动轮车辆系统非线性全局动态特性研究

为研究电动轮车辆系统在路面 电磁联合激励下的非线性振动特性,并挖掘参数与初始条件协同作用下系统全局动力学信息,建立了计及悬架系统和轮胎的非线性弹簧力和阻尼力的电动轮车辆系统两自由度1/4垂向振动非光滑非线性时变动力学模型,考虑外部激励的谐波性和随机性以及电磁激励的分段周期性,得到了含谐波性、随机性和周期性的复杂外激励模型,分析了驱动电机转速与多初值的关联性对系统动力学共存行为及其分岔的影响规律,研究了共存运动的多样性及其吸引域的拓扑构型,揭示了转速对系统全局动力学稳定性的影响机理.结果表明：电机转速与多初值协同作用诱发系统出现多样性的共存运动,共存运动吸引域的拓扑结构复杂多样,部分共存运动的振动幅值可能较大亦可能很小,其全局动力学稳定性差异较大.电机转速与初值的协同作用对电动轮车辆系统非线性振动和全局动态特性的影响不予忽视.本文研究对电动轮车辆系统的动态性能改善和结构优化具有重要的理论意义和工程价值.     

基于多体动力学的车辆道岔通过性能研究

道岔复杂的轮轨关系及其变截面特性是车辆通过道岔时引起振动甚至脱轨的关键因素.根据60kg/m钢轨18号可动心轨道岔设计布置图,在多体动力学软件中建立车辆—道岔耦合系统模型,在此基础上对车辆—道岔系统模型进行验证,仿真计算车辆侧向和直向通过道岔的动力学响应.结果表明转辙器区、辙叉区轨道截面变化和轮轨型面匹配是影响车辆动力学性能的主要因素.最后,对车辆侧向通过离散轨道模型工况下的动力学响应进行仿真计算,讨论道岔轨下整体刚度和阻尼对模型动力学性能的影响,为改善车辆通过道岔时的动力学性能、道岔轨下刚度与阻尼参数匹配提供理论基础.     

基于Adams/Car汽车转向系统力矩波动优化分析

详细阐述转向系统力矩波动的基本原理,并基于Adams/Car悬架系统模型进行DOE分析,找到对转向传动比波动影响最关键的因素;然后结合实际车辆,优化得到转向传动比波动最小时的相位角最佳值.在实车上对优化方案进行验证.     

A Novel LQG Controller of Active Suspension System for Vehicle Roll Safety

To improve vehicle roll safety during steering operation at high running speed, a new design approach for Linear Quadratic Gaussian (LQG) controller of active suspension system is proposed. Key steps of the new approach are as follows: 1) The front axle steered angle is written into a differential equation in accord with the minimum phase system and combines with the original system into the augmented system equation; 2) positive infinitesimals respectively including controls are added to the index; Thirdly, weights of the evaluating indicators of the LQG controller are determined by using analytic hierarchy process (AHP) and normalization methods based on vehicle motion statistics under the double-lane change maneuver as the typical steering maneuver. Performance comparisons are implemented between the active suspension system and the passive one under the double-lane change, slalom and fish-hook maneuvers. Results verify that the active suspension system with the proposed controller can achieve better vehicle roll safety and has a good adaptability under different steering maneuvers.     

Mechatronics in Japanese rail vehicles: active and semi-active suspensions

This paper introduces the present state of mechatronics application to the railway vehicle in Japan. The objective mechanisms in the vehicle are classified into five categories such as drive and braking, car body tilting, steering, pantograph and suspension. First, the outline of research and development in each category is described briefly. Next, the situation in the category of suspension is explained mainly on active control system and semi-active one. Finally, the prospect of research studies relating to high-speed curve negotiation is described.     

Integrated vehicle control through the coordination of longitudinal/lateral and vertical dynamics controllers: Flatness and LPV/‐based design

This paper deals with global chassis control of automotive vehicles. It focuses on the coordination of suspension and steering/braking vehicle controllers based on the interaction between the vertical and lateral behaviors of the vehicle. It is shown that the lateral acceleration and resulting roll motion of the car generate load transfers that considerably affect vehicle stability. A control law is designed in hierarchical way to improve the overall dynamics of the vehicle and cope with coupled driving maneuvers like obstacle avoidance using steering control and stop‐and‐go control using braking or driving wheel torque. This global control strategy includes two types of controllers. The first one is the longitudinal/lateral nonlinear flatness controller. Based on an appropriate choice of flat outputs, the flatness proof of a 3 DOF two‐wheel nonlinear vehicle model is established. Then, the combined longitudinal and lateral vehicle control is designed using algebraic estimation techniques to provide an accurate estimation of the derivatives and filtering of the reference flat outputs. The second part of the proposed strategy consists of a linear parameter‐varying/ suspension controller. This controller uses lateral acceleration as a varying parameter to account for load transfers that directly affect the suspension system. The coordination between the vehicle vertical and lateral dynamics is highlighted in this study, and the linear parameter‐varying/ framework ensures a specific collaborative coordination between the suspension and the steering/braking controllers, to achieve the desired performance. Simulations on a complex full vehicle model have been validated using experimental data obtained on‐board a real Renault Mégane Coupé. Copyright © 2017 John Wiley & Sons, Ltd.     

Multidisciplinary hybrid hierarchical collaborative optimization of electric wheel vehicle chassis integrated system based on driver’s feel

The optimization design of chassis integrated system mainly involves steering, suspension and brake subsystems, which is essentially a multidisciplinary design optimization. This paper mainly researches the multidisciplinary optimization of the chassis integrated system for the electric wheel vehicle, from the view of ensuring a favorable feel for the driver. The dynamic models of differential steering system, brake system, active suspension system and vehicle are established. Then, taking the coupling relationship of the chassis subsystems into account, this paper proposes an evaluating index of driver’s ride comfort (Drc), which is composed of the steering road feel, brake feel and suspension ride comfort. In order to determine the weight coefficient in the quantization formula of Drc, the technique for order preference by similarity to ideal solution (TOPSIS) method is used to overcome the subjectivity in the selection. Based on these, a multidisciplinary hybrid hierarchical collaborative optimization (HHCO) method is proposed on the basis of the collaborative optimization (CO), which consists of a system level coordinator and a coupling analyzer to solve the problem of poor convergence and the low efficiency of CO method. The optimization results show that the proposed HHCO method has excellent computational efficiency and better convergence compared with the CO method, which can further improve the steering road feel and the drive ride comfort, on the premise of ensuring the brake feel and suspension ride comfort.     

Nonlinear analysis and control of a variable-geometry suspension system

The paper proposes methods for both the analysis and the synthesis of variable-geometry suspension systems. The nonlinear polynomial Sum-of-Squares (SOS) programming method is applied in the analysis and it gives the optimal utilization of the maximum control forces on the tires. Moreover, the construction of the system can be based on the nonlinear analysis. The variable-geometry suspension system affects the wheel camber angle and generates an additional steering angle, thus the coordination of steering and wheel tilting can be handled. An LPV (Linear Parameter-Varying) based control-oriented modeling and control design for lateral vehicle dynamics are also proposed. The novelty of the method is the combination of the LPV-based control design and the SOS-based invariant set analysis. The simulation example presents the efficiency of the variable-geometry suspension system and it shows that the system is suitable to be used as a driver assistance system. In the SIL (software-in-the-loop) simulation both the dSPACE-AutoBox hardware and the CarSim simulator are used as standard industrial tools.     

四轮转向车辆操纵稳定性仿真分析

对四轮转向车辆的转向特性进行了理论分析,并对某控制策略的四轮转向车辆为例进行了仿真.建立了四轮转向车辆操纵动力学模型,分析了前轮角阶跃输入下四轮转向车辆的稳态响应和瞬态响应与传统前轮转向车辆的主要区别;在四轮转向车辆状态方程的基础上二求解出横摆角速度和侧向加速度与前轮转角的传递函数,与前轮转向车辆对比分析了传递函数零、极点位置对响应特性的影响.借助Matlab/Simulink,对四轮转向车辆进行仿真,发现仿真结果与理论分析吻合.将仿真结果与前轮转向车辆进行比较,阐明了四轮转向车辆的性能优势.研究结果可为评价四轮转向车辆的系统设计提供理论依据.     

高速4WID-4WIS自主车路径跟踪控制

高速4WID-4WIS自主车采用独立悬挂结构,所有车轮均可独市驱动、制动和转向.对自主车路径跟踪问题进行几何和运动学上的描述,结合Burckhardt非线性轮胎模型建立自主车作路径跟踪运动时的2阶动力学模型,提出自主车进行路径跟踪的协调控制体系结构,利用白抗扰控制方法设计路径跟踪系统纵向速度、侧向位移和横摆角运动3个动...