汽车AFS前照灯转角动力学建模及仿真分析

结合线性2自由度车辆动力学模型建立了车辆转向时的AFS数学模型.在Matlab/Simulink中建立了该数学模型的系统仿真模块,得到3组不同变量(不同车速、前轮转角和道路转弯半径)下的前照灯转角变化曲线.仿真结果表明,车辆动力学因素在汽车转向过程中对前照灯转角有一定影响;基于车辆动力学的AFS能够有效提高驾驶员可视范围,使车辆驾驶更加安全可靠.     

基于广义预测理论的AFS/DYC底盘一体化控制

针对现有基于AFS/DYC的车辆底盘一体化控制系统中,控制输入之间采用逻辑切换模式过于简单,无法优化车辆稳定特性的问题,提出一种基于广义预测理论的车辆底盘一体化控制系统切换算法.该算法将横摆角速度与质心侧偏角的状态变量和AFS/DYC控制输入整合于优化目标函数中,通过实时协调多个控制输入的权重,调节AFS/DYC子系统在底盘一体化控制系统中的权重,因而能连续协调AFS和DYC控制.仿真结果表明,采用该算法能实现AFS/DYC控制的平滑切换和同时工作时的协调优化.     

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。     

上海通用昂科雷新技术剖析（六）

八、适配前照灯系统（AFS） 1．适配前照灯系统（AFS）的部件组成 适配前照灯系统在车辆转弯时工作，使用电机驱动氙气大灯以适应驾驶员的视野，可以使驾驶员的视野增加到90％，其工作示意图如图29所示。     

汽车自适应前照灯系统的设计分析

阐述汽车自适应前照灯系统(AFS)的工作原理、功能设计、技术要求、软硬件设计和CAN/LIN总线应用。通过系统试验、装车应用验证AFS设计方案的可行性以及产品的使用性能,保证了车辆在各种状况下行车的最佳照明效果,实现了预期的设计目标。     

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。     

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、     

使用朗仁H6远程进行名爵GS锐腾变速器匹配

车辆信息:2016年名爵GS锐腾。案例背景:车辆更换变速器电脑后需要做匹配学习,朗仁技术中心工程师利用远程协助帮助维修人员完成匹配学习。该车型有以下常用功能:ABS的压力传感器学习、间接式胎压系统重置、偏航传感器学习、ABS加液排气;电动转向系统的电动助力转向系统学习;AFS动态前照灯水平调节系统的DHL高度传感器零位电压自学习。     

汽车主动前轮转向与防抱死制动系统集成控制研究

以车辆动力学软件Carsim和Matlab/Simulink为平台,分别建立了基于滑模变结构控制的主动前轮转向(AFS)和滑移率门限控制的防抱死制动系统(ABS)控制器模型,并将2种控制系统进行了集成,建立了联合仿真模型。仿真结果表明,在分离路面紧急制动工况下,通过将AFS与ABS进行集成控制,能够进一步提高ABS的制动效能,在保持车辆制动稳定性的同时缩短了制动距离。     

2016款江淮瑞风A60车自适应前照灯系统出现报警

<正>故障现象一辆2016款江淮瑞风A60车(车辆型号为HFC7151CTV),搭载1.5T发动机,配备自适应前照灯系统(AFS),累计行驶里程约为2.1万km。车主反映,组合仪表上的AFS故障灯点亮。故障诊断接车后首先试车验证故障现象。踩下制动踏板,按下电源开关,起动发动机,此时,组合仪表上的AFS故障灯长亮,同时信息中心提示"随动转向照明系统故障,请注意检查维修"(图1)。询问车主得知,前不久车辆发生过一次事故碰撞,在修理厂做了事故维修,更换了两侧前照灯,随后组合仪表上的AFS故障灯点亮。     

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。     

Handling Capabilities of Vehicles in Emergencies Using Coordinated AFS and ARMC Systems

In this paper, an advanced control technique that can be implemented in hard emergency situations of vehicles is introduced. This technique suggests integration between Active Front Steering (AFS) and Active Roll Moment Control (ARMC) systems in order to enhance the vehicle controllability. For this purpose, the AFS system applies a robust sliding mode controller (SMC) that is designed to influence the steering input of the driver by adding a correction steering angle for maintaining the vehicle yaw rate under control all the time. The AFS system is then called active-correction steering control. The ARMC system is designed to differentiate the front and rear axles' vertical suspension forces in order to alter the vehicle yaw rate and to eliminate the vehicle roll motion as well. Moreover, the operation of the SMC is based on tracking the behavior of a nonlinear 2-wheel model of 2-DOF used as a reference model. The 2-wheel model incorporates real tire characteristics, which can be inferred by the use of trained neural networks. The results clearly demonstrate the enhanced characteristics of the proposed control technique. The SMC with the assistance of the ARMC provides less correction of the steering angle and accordingly reduces the possibility of occurrence of the saturation phenomenon that is likely to take place in the operation of the SMC systems.     

Handling Capabilities of Vehicles in Emergencies Using Coordinated AFS and ARMC Systems

In this paper, an advanced control technique that can be implemented in hard emergency situations of vehicles is introduced. This technique suggests integration between Active Front Steering (AFS) and Active Roll Moment Control (ARMC) systems in order to enhance the vehicle controllability. For this purpose, the AFS system applies a robust sliding mode controller (SMC) that is designed to influence the steering input of the driver by adding a correction steering angle for maintaining the vehicle yaw rate under control all the time. The AFS system is then called active-correction steering control. The ARMC system is designed to differentiate the front and rear axles' vertical suspension forces in order to alter the vehicle yaw rate and to eliminate the vehicle roll motion as well. Moreover, the operation of the SMC is based on tracking the behavior of a nonlinear 2-wheel model of 2-DOF used as a reference model. The 2-wheel model incorporates real tire characteristics, which can be inferred by the use of trained neural networks. The results clearly demonstrate the enhanced characteristics of the proposed control technique. The SMC with the assistance of the ARMC provides less correction of the steering angle and accordingly reduces the possibility of occurrence of the saturation phenomenon that is likely to take place in the operation of the SMC systems.     

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.     

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.     

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.     

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。     

Optimum distribution of yaw moment for unified chassis control with limitations on the active front steering angle

This paper describes an optimum distribution method for yaw moment for use with unified chassis control (UCC) with limitations on the active front steering (AFS) angle. Although the UCC has been assumed to have no AFS angle limitation in the literature, a physical limitation exists in real applications. To improve upon the previous method, a new optimum distribution method for yaw moment is proposed that takes this limitation into account. This method derives an optimum longitudinal/lateral force using the Karush-Kuhn-Tucker (KKT) optimality condition, and a simulation is performed to validate the proposed method. The simulation results indicate that the limitation on the AFS angle increases longitudinal braking force and, therefore, reduces the vehicle speed and the side-slip angle.     

Integrated fuzzy/optimal vehicle dynamic control

There are basically two methods to control yaw moment which is the most efficient way to improve vehicle stability and handling. The first method is indirect yaw moment control, which works based on control of the lateral tire force through steering angle control. It is mainly known as active steering control (ASC). Nowadays, the most practical approach to steering control is active front steering (AFS). The other method is direct yaw moment control (DYC), in which an unequal distribution of longitudinal tire forces (mainly braking forces) produces a compensating external yaw moment. It is well known that the AFS performance is limited in the non-linear vehicle handling region. On the other hand, in spite of a good performance of DYC in both the linear and non-linear vehicle handling regions, continued DYC activation could lead to uncomfortable driving conditions and an increase in the stopping distance in the case of emergency braking. It is recommended that DYC be used only in high-g critical maneuvers. In this paper, an integrated fuzzy/optimal AFS/DYC controller has been designed. The control system includes five individual optimal LQR control strategies; each one, has been designed for a specific driving condition. The strategies can cover low, medium, and high lateral acceleration maneuvers on high-μ or low-μ roads. A fuzzy blending logic also has been utilized to mange each LQR control strategy contribution level in the final control action. The simulation results show the advantages of the proposed control system over the individual AFS or DYC controllers.