4WIS-4WID车辆横摆稳定性AFS+ARS+DYC滑模控制

针对四轮独立转向-独立驱动(4WIS-4WID)车辆,应用滑模变结构控制理论,设计前、后轮主动转向(AFS+ARS)控制器、横摆角速度直接横摆力矩控制(DYC)控制器和质心侧偏角DYC控制器。为协调横摆角速度和质心侧偏角间的耦合设计了协调控制器,对附加横摆力矩实施车轮驱动/制动协同分配。引入2自由度4WIS-4WID车辆参考模型,并将其横摆角速度和质心侧偏角的状态反馈给AFS+ARS控制器,完成AFS+ARS和DYC控制系统的集成。加入不确定车辆自身参数和阵风干扰,将控制策略应用于16自由度4WIS-4WID车辆模型上进行仿真验证,并与单纯AFS+ARS、传统PID和差压制动的DYC进行对比。结果表明,所设计的控制策略同时提高了系统的抗干扰性和精确性;拓展了系统的稳定域,进一步提高了车辆的主动安全性。     

智能车灯的模糊控制器设计

针对传统汽车照明系统只能用手动控制,在路况复杂或者环境恶劣的情况下不能及时有效地提供良好照明的问题,文章介绍了一种自适应车灯前照明控制系统（AFS）并对其控制方法进行了研究。运用模糊控制理论并使用MATLAB／SIMUuNK软件中的FUZZY模块,对水平和垂直方向上的车灯偏转设计了模糊控制器。指出AFS应用前景广阔,模糊控制技术可以为将来智能车灯的发展提供参考。     

雅马哈摩托车AFS自适应前照灯系统简介(1)

AFS是Adaptive Front-lighting System的英文缩写,中文的意思是自适应前照灯系统。目前,AFS系统已经在不少豪华轿车（诸如BMW5系、奔驰E级、奥迪A8、凌志R系列等）上开始应用,具有AFS功能的轿车前照灯光束能自动跟踪行驶道路的变化（见图1）,尤其是在弯道上行驶时显示出照明优势,极大地提高了车辆夜间、     

前照灯自适应系统(AFS)试验方法研究

介绍了前照灯自适应系统(Adaptive Front-Lighting Systems,以下简称AFS)的发展现状,研究了AFS的法规ECE R123/01《关于机动车自适应前照灯系统(AFS)认证的统一规定》中不同AFS照明模式(C、V、E、W)的配光要求和试验方法。     

便捷性AFS仿真实验平台评价指标体系研究

汽车AFS(Adaptive Front Lighting System)系统是汽车随动控制的新技术,对其仿真平台的研究在国内外也是一个具有前瞻性的领域.本文通过对AFS系统实验验证平台设计的要求及其必要性进行了分析,并结合国内外有关车灯控制方面的法规,以仿真试验平台的便捷性为核心,从技术先进性、经济性和可靠性这三方面以及所采用的基于计算机软件CATIA的优化设计方面提出了一套基于AFS仿真试验平台的评价指标体系.这些指标将对今后该实验平台的改进和企业的研发起到积极作用.     

面向配光特性的汽车AFS动态转角数学模型研究

针对常用的汽车自适应前照灯(AFS)转角数学模型存在的问题,对汽车车身侧倾角与转弯半径及车速之间关系进行研究,建立面向配光特性的汽车AFS动态转角数学模型,通过AFS的二维转动对侧倾后AFS照射方向进行修正。结果表明,与常用的AFS转角数学模型相比,AFS动态转角数学模型求得的前照灯转角在yz平面上补偿角αx(t)最大达0.7°,占yz平面上设计旋转角度的28%,解决了侧倾后常用的AFS配光特性难以达到国家标准GB4599-2007要求的问题。     

AFS稳定细粒土结合料的性能与应用

AFS是由石灰、粉煤灰、激活剂配制的一种新型细粒土结合料。本文研究AFS对细粒土和细粒土质砂砾的稳定作用，并与水泥、石灰稳定土的强度进行了对比。结果表明AFS稳定土强度优于水泥、石灰稳定土。AFS适应于稳定细粒土，也可用于稳定细粒土质砂砾。实际工程应用表明，AFS稳定土作道路基层具有良好的工程应用性。     

基于多Agent和VANET的自适应汽车前灯控制系统研究

为改善汽车照明条件以极大减少夜间事故的发生率,将汽车ad hoc网络(VANET)和多Agent系统引入自适应前灯系统设计,提出合作型自适应前灯系统来帮助改善AFS的照明效果。首先介绍了AFS的工作原理和系统的机械结构,并简要阐述了当前的VANET和多Agent系统的进展。然后,基于VANET和多Agent技术的发展,提出CAFS系统,详细介绍了CAFS系统的设计和相应的智能控制策略。最后,对所提出的CAFS进行了仿真实验,仿真实验表明提出的方法具有可操作性并能有效的提高夜间照明的效果。     

新款丰田大霸王新技朮剖析(四)

AFS OFF开关及ECU位置,如图21所示。维修说明:新一代智能前照灯系统可以通过AFS OFF指示灯来判断系统是否有故障,当AFS OFF灯长亮时。说明系统处于关闭状态,如果指示灯以1Hz频率闪烁,表示系统有故障,对于这个故障码,必须有专用设备来读取查看,如果指示灯以     

AFS系统关键技术研究

介绍AFS系统的产生背景、作用、国内外发展概况及趋势。根据车辆的速度、转向盘转角、车辆的前后倾角的关系,提出该系统的数学模型,在此基础上研究基于该数学模型的控制方法以及对于失效情况的处理方式。最后建立可行的AFS硬件系统,并进行实验室验证。     

机械式前轮主动转向系统的原理与应用

以宝马轿车上选装的主动转向系统为例,详细介绍了该系统的组成、双行星齿轮机构的结构及工作模式,以及该系统可变传动比、稳定车辆等功能的实现原理和系统安全性设计。指出通过与其他动力学控制系统一起实现底盘一体化集成控制将是主动转向技术未来的发展方向。     

Study on the performance of active front steering system

The performance of a steering system equipped with active front steering (AFS) device is investigated with the consideration of AFS intervention and a proposed dynamic model. Firstly, the kinematics and dynamics of AFS are illustrated based on the mechanism of AFS with planetary gear set and a detailed dynamic model. Furthermore, a basic control on the voltage of DC motor at AFS actuator is proposed. It is realized by a proportional controller that the input is the difference of desired steering ratio and a conventional gear ratio. Finally, two numerical simulations are carried out. One is on-center handling test to demonstrate the basic characteristics of AFS. The other simulation is to demonstrate the effects of vehicle speed, frequency of steering input and AFS intervention on steering system performance. It is shown that the proposed AFS dynamic model is capable to simulate dynamic performance of AFS. The effect of AFS intervention on turning efforts at hand steering wheel is inevitable and the turning comfort is deteriorated to some extent.     

自适应前照灯运动学建模及系统开发

根据自适应前照灯系统(AFS)的功能要求,推导了车辆参数(车速、转向盘转角和车身仰俯角)与车灯光轴沿水平和垂直两个方向的偏转角度之间的关系,建立了自适应前照灯系统的运动学模型。在此基础上开发了自适应前照灯系统硬件结构,并在实验室建立了该系统的试验平台,对所提出的运动学模型进行了验证,效果良好。     

Research on interactive steering control strategy between driver and AFS in different game equilibrium strategies and information patterns

In the past decade, several publications have shown that it is advisable to design an advanced driver assistance system using a shared control structure. This paper is concerned with the modelling and verification of an interactive steering control strategy between a driver and an active front steering (AFS) controller to investigate the complex interactions between human driver and an AFS system. Using game theory as a general framework, a more comprehensive mathematical model system of interactive steering control potentially applicable to explore human drivers’ behaviours in shared control of intelligent vehicles is presented and discussed in this paper. The effects of different information patterns, namely the open-loop pattern and the closed-loop feedback pattern on modelling shared steering control between driver and AFS have been investigated. Simulation and hardware-in-loop implementation results prove the validity of steering interactive modelling in different game information patterns. Specifically, the results show that, in the Nash equilibrium strategy situation, the driver and the AFS controller may become more rational and reasonable in the process of completing the same dynamic task in the closed-loop feedback information patterns compared to the open-loop ones; and the differences between feedback Nash and feedback Stackelberg may depend on the step size of discretisation.     

主动前轮转向客车的操纵稳定性仿真分析

建立某大型客车的含侧向、横摆及侧倾三自由度动力学模型,通过方向盘角阶跃转向仿真结果和试验数据的比较,验证了仿真分析的准确性。采用横摆角速度跟踪主动前轮转向控制策略,结合比例积分控制方法,在考虑作动器动态特性和前轮转角饱和特性的基础上,对主动前轮转向控制前后的车辆进行直线行驶下的侧向风扰动和湿滑路面急转弯情况下的仿真对比分析。结果表明,主动前轮转向控制后的车辆其操纵稳定性和行车安全性都有较大的提高。     

Active front wheel steering model and controller for integrated dynamics control systems

We report a model and controller for an active front-wheel steering (AFS) system. Two integrated dynamics control (IDC) systems are designed to investigate the performance of the AFS system when integrated with braking and steering systems. An 8-degrees-of-freedom vehicle model was employed to test the controllers. The controllers were inspected and compared under different driving and road conditions, with and without braking input, and with and without steering input. The results show that the AFS system performs kinematic steering assistance function and kinematic stabilisation function very well. Three controllers allowed the yaw rate to accurately follow a reference yaw rate, improving the lateral stability. The two IDC systems improved the lateral stability and vehicle control and were effective in reducing the sideslip angle.     

主动前轮转向控制技术研究现状与展望

主动前轮转向系统提供的独立于驾驶员的转向干预可以提高车辆的操纵稳定性.文中介绍了横摆角速度反馈和横摆角速度与侧偏角联合反馈的稳定性控制算法;阐述了主动前轮转向系统分别与几种动力学控制系统实行集成控制的方法.最后在结论中指出底盘一体化控制将是主动转向技术未来的发展方向.     

Integrated control of ground vehicles dynamics via advanced terminal sliding mode control

An integrated vehicle dynamics control (IVDC) algorithm, developed for improving vehicle handling and stability under critical lateral motions, is discussed in this paper. The IVDC system utilises integral and nonsingular fast terminal sliding mode (NFTSM) control strategies and coordinates active front steering (AFS) and direct yaw moment control (DYC) systems. When the vehicle is in the normal driving situation, the AFS system provides handling enhancement. If the vehicle reaches its handling limit, both AFS and DYC are then integrated to ensure the vehicle stability. The major contribution of this paper is in improving the transient response of the vehicle yaw rate and sideslip angle tracking controllers by implementing advanced types of sliding mode strategies, namely integral terminal sliding mode and NFTSM, in the IVDC system. Simulation results demonstrate that the developed control algorithm for the IVDC system not only has strong robustness against uncertainties but also improves the transient response of the control system.     

Coordinated control of ESC and AFS with adaptive algorithms

This paper presents a coordinated control of electronic stability control (ESC) and active front steering (AFS) with adaptive algorithms for yaw moment distribution in integrated chassis control (ICC). In order to distribute a control yaw moment into control tire forcres of ESC and AFS, and to coordinate the relative usage of ESC to AFS, a LMS/Newton algorithm (LMSN) is adopted. To make the control tire forces zero in applying LMS and LMSN, the zero-attracting mechanism is adopted. Simulations on vehicle simulation software, CarSim®, show that the proposed algorithm is effective for yaw moment distribution in integrated chassis control.