主动悬架的操纵稳定性控制研究

本文分析主动悬架力对车辆操纵稳定性的影响关系,及基于模糊滑模控制方法,设计以提高操纵稳定性为目标的主动悬架控制器。并进行仿真试验验证该控制器的有效性。结果表明该主动悬架控制器能够提高车辆横向操纵性能。     

基于μ综合鲁棒控制的EPS车辆操纵稳定性研究

在传感器噪声、参数摄动、路面干扰等因素的影响下,车辆EPS控制系统性能会不同程度下降,对汽车操纵稳定性造成一定的影响.为提高EPS控制系统性能,基于μ综合理论和鲁棒控制方法,选取相关性能指标设计了新型μ控制器,构造了装备EPS系统的整车μ综合控制系统.仿真与μ分析结果表明:基于μ综合算法的控制器具有良好稳定鲁棒性和性能鲁棒性,有效地提高了车辆操纵稳定性和安全性.     

基于近似模型的车辆操纵稳定性及平顺性的优化研究

简述了基于近似模型的车辆操纵稳定性及平顺性的优化设计方法.利用多体动力学软件ADAMS/Car建立了某轿车整车多体动力学模型,并确定了车辆操纵稳定性及平顺性的评价目标.以悬架弹簧刚度、减振器阻尼特性和横向稳定杆刚度为设计变量,利用近似优化数学模型对该轿车进行了操纵稳定性和行驶平顺性的多目标优化计算.结果表明,近似模型技术对于汽车性能的平衡优化是一种十分有效的方法.     

ADAMS软件在汽车操纵稳定性研究中的应用

以转向盘转角阶跃输入为例,说明采用ADAMS对车辆操纵稳定性进行研究评价的方法及过程。利用AD-AMS软件可以进行不同车速、不同载荷下的操纵稳定性仿真,能够对车辆的操纵稳定性做出预测,为设计提供参考,这对于车辆开发前期对车辆性能的预测十分重要。     

基于车辆动力学模型的换道轨迹规划研究

针对自动驾驶车辆换道轨迹规划时的操纵稳定性问题，基于CarSim/Simulink仿真平台建立了车辆动力学模型，构建了轨迹规划系统框架，通过轨迹信息后处理并提出了目标函数设计，进行了横向控制序列采样以保证车辆的稳定与极限性能，完成了算法对轨迹的综合评价选优。随后开展了仿真试验，对比分析了轨迹跟踪控制系统下的实际轨迹、最优规划方法所规划的换道轨迹。仿真结果表明，该轨迹规划系统框架及算法模型能有效提高车辆的操纵稳定性，可实现冰雪路面等极端工况下自动驾驶车辆换道轨迹规划。     

多体动力学仿真技术在某越野汽车开发中的应用

应用仿真技术,在某越野汽车开发早期,通过仿真结果与整车道路试验对比,验证了车辆模型的正确性.根据此模型对所开发车辆的操纵稳定性进行预测,提出车辆改进方案,改善所设计车辆的操纵稳定性.     

基于多主体的车辆底盘集成控制扩展框架仿真研究

分别设计以提高平顺性和操纵稳定性为目标的主动悬架控制器.并基于多主体的控制器组织方法建立底盘集成控制扩展框架,使主动悬架控制器与包含主动转向、主动驱动/制动力矩分配的集成控制系统协调工作.在Matlab/Simulink仿真环境中研究该控制框架在极限操纵工况下的性能.仿真结果表明:局部控制器主体可方便地增加到集成控制系统中,体现了基于多主体的底盘集成控制框架的可扩展性;该扩展框架能同时改善车辆的操纵稳定性和行驶平顺性.     

全局耦合消扭悬架系统动力学仿真研究(英文)

介绍了一种全局耦合消扭悬架的原理和结构,利用ADAMS建立了装备有该消扭悬架的车辆模型,对其消扭性能和操纵稳定性进行了仿真试验研究,研究结果表明该消扭悬架在能有效地减小对车身的扭转,降低轮荷最大值,改善车轮的垂直载荷的均匀性,改善车辆的接地性能,不会对车辆的操纵稳定性带来不利影响.     

车道急剧变换试验方法研究与探讨

随着车辆性能的发展与完善,对整车操纵稳定性能提出了更高的要求,国际上出现越来越多的相关评价标准。文章详细介绍了ISO3888-2避障试验车道以及试验方法,针对试验方法搭建试验测试系统,并选取4款车型进行实车试验。通过对试验主客观结果分析,为该国际标准转化为国家标准提出三点建议,以供相关部门参考。     

汽车手操纵驻车系统的效率研究

在进行车辆手操纵驻车系统设计开发时,对手操纵驻车系统的效率选取直接决定该系统实际性能的好坏,由于国内暂无相关资料明确给出该效率的参考值,不同设计人员多以自身经验主观选取,导致实际手操纵驻车要么力偏大,要么行程偏大,驻车效果不能符合设计预期。文中结合开发经验和实测数据,对手操纵驻车系统的效率进行研究分析,提出了手操纵驻车系统效率经验参考值。     

麦弗逊悬架系统仿真分析应用研究

汽车悬架类型的选择和悬架参数的差异对汽车的操纵稳定性和行驶平顺性具有重要的影响。主要分析了麦弗逊悬架的结构特点,并通过CATIA和ADAMS软件建立麦弗逊悬架的3D模型,对其进行仿真分析,得出悬架参数的优化设计方法。     

非满载液罐半挂汽车列车侧向耦合动力学模型

为方便液罐半挂汽车列车（Tractor Semi-trailer Tank Vehicle,TSTTV）罐-车整体的优化设计匹配,综合提高整车的侧倾稳定性、侧向动力学稳定性及操纵特性,基于Lagrange方法和椭圆规摆等效机械液体晃动模型建立TSTTV的整车侧向耦合动力学模型,其典型特征是实现罐内液体侧向晃动与车辆横摆运动、侧向运动、悬挂质量的侧倾运动及非线性侧向轮胎力的集成一体化建模,贯通液体晃动动力学与车辆侧向动力学稳定性之间的联系。通过开环正弦停滞转向输入操作响应对所建立的模型进行分析评价,考察车辆横摆角速度、质心侧偏角、侧倾角、侧向载荷转移率及液体晃动角等状态量在2种充液比（F_L=40%,80%）及2种罐体椭圆率（Δ=1.0,1.3）下的响应。研究结果表明：所建立的TSTTV模型可以实现液体侧向晃动作用下的车辆侧向耦合动力学仿真分析,能够反映充液比、罐体截面椭圆率等运输条件和罐体几何参数对整车侧倾稳定性、侧向动力学稳定性及操纵特性的影响;基于该模型可以针对液体介质、充液比及道路环境等运输条件因素的影响,研究以提高整车侧向动力学稳定性为目标的TSTTV灌-车整体的优化设计匹配问题,这对提升液罐车的设计性能、提高行驶的安全性和运输效率具有重要意义。     

Lateral dynamics of single unit skid-steered tracked vehicle

In the design and development of high-speed tracked vehicles, it is necessary to have an understanding of the interrelationship between the terrain factors and the vehicle characteristics during steering. The handling behavior of skid-steered tracked vehicles is more complex than that of wheeled vehicles because of non-linear characteristics arising from the sliding interface between the track and the ground. In the present work, a five degree-of-freedom (DOF) steering model of a tracked vehicle is developed, and the handling behavior during non-stationary motion is studied when operating at high and low speeds. It is demonstrated that the inclusion of roll and pitch DOF changes the steering response when compared to the response from three DOF models proposed earlier by several researchers. This is due to the strong coupling between the pitch and yaw motions. The effect of the initial forward velocities on the trajectory of the vehicle during non-stationary motion is also studied. It is observed from the results that the stability is influenced by the type of steering input, steering ratio and vehicle forward speed.     

Magneto-rheological suspensions for improving ground vehicle’s ride comfort,stability, and handling

ABSTRACT

A state-of-the-art discussion on the applications of magneto-rheological (MR) suspensions for improving ride comfort, handling, and stability in ground vehicles is discussed for both road and rail applications. A historical perspective on the discovery and engineering development of MR fluids is presented, followed by some of the common methods for modelling their non-Newtonian behaviour. The common modes of the MR fluids are discussed, along with the application of the fluid in valve mode for ground vehicles’ dampers (or shock absorbers). The applications span across nearly all road vehicles, including automobiles, trains, semi-trucks, motorcycles, and even bicycles. For each type of vehicle, the results of some of the past studies is presented briefly, with reference to the originating study. It is discussed that Past experimental and modelling studies have indicated that MR suspensions provide clear advantages for ground vehicles that far surpasses the performance of passive suspension. For rail vehicles, the primary advantage is in terms of increasing the speed at which the onset of hunting occurs, whereas for road vehicles – mainly automobiles – the performance improvements are in terms of a better balance between vehicle ride, handling, and stability. To further elaborate on this point, a single-suspension model is used to develop an index-based approach for studying the compromise that is offered by vehicle suspensions, using the H₂ optimisation approach. Evaluating three indices based on the sprung-mass acceleration, suspension rattlespace, and tyre deflection, it is clearly demonstrated that MR suspensions significantly improve road vehicle’s ride comfort, stability, and handling in comparison with passive suspensions. For rail vehicles, the simulation results indicate that using MR suspensions with an on-off switching control can increase the speed at which the on-set of hunting occurs by as much as 50% to more than 300%.     

Nonlinear Design Approach to Four-Wheel-Steering Systems Using Neural Networks

Four-wheel-steering (4WS) systems have been studied and developed with remarkable success from the viewpoint of vehicle dynamics. Most of the control methods require a linearized bicycle model of the actual vehicle system which is however strongly influenced by tire nonlinearity. This paper proposes a new method to design the 4WS system taking into account the nonlinear characteristics of tires and suspensions. For this purpose integration of artificial neural network and linear control theory is introduced for the identification and control of a nonlinear vehicle model structured using a software for multi-body dynamic analysis (ADAMS). This model takes into account the nonlinear characteristics of actual vehicles with tires modeled by “magic formula“. The results of computer simulations show that the proposed nonlinear approach is efficient in improving the handling and stability of vehicles.     

Kurshaltungskennwerte und ihre Abhangigkeit von Fahrzeugdaten*

Vehicle Handling Characteristics and Their Relationship to Vehicle Design Parameters

This paper reviews currently used test procedures for the determination of vehicle handling characteristics in the time and frequency domain. Driver subjective opinions lead to preferred tendencies or ranges of these quantities. The results of closed-loop tests show the adaptability of drivers to the dynamic characteristics of vehicles. The relationship between handling characteristics and design parameters is obtained from the analysis of a simple vehicle model. Comparison of these results with the prefered ranges found in closed-loop tests yields aids for the design of vehicles.     

A novel integrated chassis controller for full drive-by-wire vehicles

In this paper, a systematic design with multiple hierarchical layers is adopted in the integrated chassis controller for full drive-by-wire vehicles. A reference model and the optimal preview acceleration driver model are utilised in the driver control layer to describe and realise the driver's anticipation of the vehicle's handling characteristics, respectively. Both the sliding mode control and terminal sliding mode control techniques are employed in the vehicle motion control (MC) layer to determine the MC efforts such that better tracking performance can be attained. In the tyre force allocation layer, a polygonal simplification method is proposed to deal with the constraints of the tyre adhesive limits efficiently and effectively, whereby the load transfer due to both roll and pitch is also taken into account which directly affects the constraints. By calculating the motor torque and steering angle of each wheel in the executive layer, the total workload of four wheels is minimised during normal driving, whereas the MC efforts are maximised in extreme handling conditions. The proposed controller is validated through simulation to improve vehicle stability and handling performance in both open- and closed-loop manoeuvres.     

Independent control of all-wheel-drive torque distribution

The sophistication of all-wheel-drive (AWD) technology is approaching the point where the drive torque to each wheel can be independently controlled. This potentially offers vehicle handling enhancements similar to those provided by dynamic stability control, but without the inevitable reduction in vehicle acceleration. Independent control of AWD torque distribution would therefore be especially beneficial under acceleration close to the limit of stability. A vehicle model of a typical sports sedan was developed in Simulink, with fully independent control of torque distribution. Box–Behnken experimental design was employed to determine which torque distribution parameters have the greatest impact on the vehicle course and acceleration. A proportional-integral control strategy was implemented, applying yaw rate feedback to vary the front–rear torque distribution and lateral acceleration feedback to adjust the left–right distribution. The resulting system shows a significant improvement over conventional driveline configurations under aggressive cornering acceleration on a high-μ surface. The performance approaches the theoretical limit for these conditions. In the medium term, such a system is only likely to be economically viable for premium vehicles. However, a future revolution of powertrain technology towards, for example, wheel-mounted motors, could realize these handling benefits far more widely.     

Sensitivity of Driver-Vehicle Performance to Vehicle Characteristics Revealed in Open-loop Tests

The advantages of being able to objectively specify desirable vehicle handling characteristics, which can be determined without recourse to closed-loop tests on a prototype vehicle, are widely recognised. This paper reviews the studies that have attempted to find a relationship between closed-loop task performance, and driver subjective opinion, and various steady-state and transient characteristics revealed in open-loop tests of the vehicle. It is found that the level of definition of these relationships is not sufficient to justify mandatory regulations for vehicle design. However, the basic requirements for steering control sensitivity, and the rapidity and stability of the fixed-control dynamic response of vehicles in normal manoeuvres, are beginning to emerge. Data are particularly lacking for the closed-loop effects of vehicle sideslipping characteristics, free-control responses and vehicle behaviour in limit manoeuvres.     

Independent control of all-wheel-drive torque distribution

The sophistication of all-wheel-drive (AWD) technology is approaching the point where the drive torque to each wheel can be independently controlled. This potentially offers vehicle handling enhancements similar to those provided by dynamic stability control, but without the inevitable reduction in vehicle acceleration. Independent control of AWD torque distribution would therefore be especially beneficial under acceleration close to the limit of stability. A vehicle model of a typical sports sedan was developed in Simulink, with fully independent control of torque distribution. Box-Behnken experimental design was employed to determine which torque distribution parameters have the greatest impact on the vehicle course and acceleration. A proportional-integral control strategy was implemented, applying yaw rate feedback to vary the front-rear torque distribution and lateral acceleration feedback to adjust the left-right distribution. The resulting system shows a significant improvement over conventional driveline configurations under aggressive cornering acceleration on a high-μ surface. The performance approaches the theoretical limit for these conditions. In the medium term, such a system is only likely to be economically viable for premium vehicles. However, a future revolution of powertrain technology towards, for example, wheel-mounted motors, could realize these handling benefits far more widely.