重型车辆侧翻预警算法研究

针对重型车辆在行驶过程中非绊倒型侧翻预警实现问题,建立了三自由度车辆侧翻模型并设计了以侧翻时间（TTR）为预警标准的算法。考虑到预警算法中动态门限值中某些参数难于直接测取的问题,将Kalman滤波技术融合于其中,提出了基于车身侧倾角估计的TTR侧翻预警算法,实现车辆动态侧翻特性的精确预测。而后利用Matlab/Simulink与Trucksim软件联合仿真对侧翻预警算法进行验证。结果表明,基于车身侧倾角估计的重型车辆侧翻预警算法能够顺利运行,为非绊倒型侧翻预警问题提供了一种新的设计思路。     

基于电动助力转向的汽车防侧翻预警系统研究

为了使驾驶员能主动感知车辆侧倾状态、防止车辆侧翻,提出了一种新型基于电动助力转向的防侧翻预警系统;利用横向载荷转移率的门限值作为防侧翻预警控制的触发条件,采用助力电机电流补偿控制,当车辆侧倾较大,即横向载荷转移率超过门限值时,预警控制系统使驾驶员操纵转向盘力矩增大,结合侧翻报警灯工作,提醒驾驶员车辆正处于危险工况;MATLAB/simulink中的仿真分析验证了防侧翻预警控制器能有效的提高车辆的操稳性。     

基于主动转向和差动制动的车辆防侧翻控制

目前车辆防侧翻技术主要有主动转向或差动制动,但单独的主动转向会导致车轮转角调整过大,差动制动会导致制动力过大出现轮胎抱死,而且预警是依据侧向加速度信号,预警时间过慢,导致不安全.为了提高控制能力,通过建立车辆侧翻模型提出了LTR预警方法,能准确快速地计算车辆侧翻概率.并采用了主动转向和差动制动联合的防侧翻控制,在Mat-lab/simulink中设计出了联合控制算法.算法通过改变PI参数值和制动力增益系数K,既保证了不破坏车辆的车道保持功能,又减小了速度在-定时间内的下降率.仿真结果表明,优化控制防止了车辆侧翻,避免制动力过大,保证了系统安全性,确实为防侧翻控制设计提供了参考.     

SUV侧翻预警系统硬件在环实时仿真设计

针对运动型多功能汽车（SUV）设计一种基于动态侧翻预警的控制系统。以横向载荷转移率作为侧翻指标,研究TTR侧翻预警算法及硬件实现,并应用差动制动方法对车辆进行侧倾控制。在汽车模拟器上进行硬件在环实时仿真实验,选取双移线和Fishhook工况对SUV动态侧翻预警控制性能进行分析。仿真结果显示,基于预警的防侧翻控制系统不仅可以有效地提高车辆的横摆稳定性和侧倾稳定性,且只有在出现侧翻危险时才起动制动装置,节省了制动能量。     

运动型多功能汽车动态侧翻预警系统研究

汽车侧翻是一种迅速发生且非常致命的事故,为及时准确地获得汽车侧翻状态信息,针对运动型多功能汽车(SUV)研究了一种动态侧翻预警系统。根据侧翻运动规律建立了三自由度SUV侧翻动力学模型,研究了SUV动态侧翻预警算法,设计了以16位单片机为核心的动态侧翻预警系统硬件结构。对典型工况下的SUV动态侧翻预警性能进行了实验分析,结果表明:该系统计算汽车侧翻预警时间(TTR)准确且实时性好,减小重心高度、方向转角及车速,增加轮距宽度将有助于获得更大的动态侧翻预警时间,提高汽车防侧翻主动安全性。     

智能车载感知与侧翻预警系统的设计

为了防止汽车在行驶过程中发生侧翻,使汽车始终处在安全工况下行驶,减少交通事故,设计了一种基于ARM9的智能车载感知和侧翻预警系统,对汽车在途行驶时的侧倾角和侧倾角速度进行监测,并采用多阶递推模型对汽车侧倾姿态进行预测,当预测到侧倾达到极限工况时发出报警信息,提醒驾驶人员注意并采取相应减少侧向加速度的措施,从而达到预防汽车侧翻事故的发生,并基于VB2005,Matlab和NIMeasurement Studio开发了车载感知与侧翻预警系统软件,进行了系统仿真。实车道路试验与系统仿真实验进行了比较,结果表明:车载感知和预警系统能够及时准确预测汽车侧翻,提高汽车主动安全。     

基于无线通信的车辆主动防撞预警系统设计

提出了一种基于无线通信的车辆主动防撞预警系统,利用梯度方向直方图特征与支持向量机配合单目测距模型实现前方车辆的实时检测与测距,并利用传感器无线通信网络获取相对车速信息,最后根据相对车距与相对车速配合TTC预警模型实现碰撞预警。试验结果表明,系统平均处理时间100ms,车辆检测准确率95%,单目测距误差小于±4m,实现了实时、准确的车辆预警。     

线控转向汽车防侧翻稳定性控制

通过线控转向（Steer by Wire,SBW）系统控制汽车方向盘转角提高某汽车在极限行驶中抗侧翻能力.建立SBW整车模型,基于紧急避让、紧急掉头和蛇行运动等3种危险操纵稳定性工况分析,得出该车易侧翻的结论.提出基于横向载荷转移率(Lateral Load Transfer Ratio, LTR)的车辆动态防侧翻控制算法,通过SIMULINK与CarSim的联合仿真平台,建立转向优化控制模型.仿真结果表明在典型工况下该车防侧翻性能得到明显改善.     

基于模型预测的客车侧翻控制方法

为提高客车侧翻稳定性，解决单独差动制动控制效果不稳定的问题，提出了一种基于模型预测控制的主动转向/差动制动联合控制方法。针对计算侧翻指标LTR难度较大的问题，建立了无迹卡尔曼滤波(Unscented Kalman Filter, UKF)状态参数估计器对LTR值进行估计。基于模糊控制理论设计了主动转向、差动制动下层控制器。通过TruckSim/Simulink联合仿真平台对客车在鱼钩试验和阶跃试验典型工况下进行了仿真分析，结果表明，设计的MPC控制器相比单独差动制动控制具有更好的控制效果和控制稳定性。     

基于逻辑门限值的客车ABS硬件在环测试研究

针对ABS控制器开发过程中纯数值仿真过于理想化,实车试验成本高、周期长等缺点,设计并搭建了客车ABS硬件在环仿真测试系统;系统由xPC目标实时仿真环境、气制动系统及整车动力学模型组成;气制动系统按照真实客车制动系统并配合力传感器搭建;整车动力学模型由轮胎模型、七自由度车辆模型、制动器模型等组成,并利用Simulink建模;在ABS控制策略中引入逻辑门限值控制,在客车ABS硬件在环仿真测试系统上测试了客车在高附着系数、低附着系数及对接路面上的制动情况;试验表明:逻辑门限值控制能很好地将车轮滑移率控制在最佳滑移率附近,具有较好的控制精度及鲁棒性。     

Detection of Impending Vehicle Rollover with Road Bank Angle Consideration Using a Robust Fuzzy Observer

 This article describes a method of vehicle dynamics estimation for impending rollover detection. We estimate vehicle dynamic states in presence of the road bank angle as a disturbance in the vehicle model using a robust observer. The estimated roll angle and roll rate are used to compute the rollover index which is based on the prediction of the lateral load transfer. In order to anticipate rollover detection, a new method is proposed to compute the time to rollover (TTR) using the load transfer ratio (LTR). The nonlinear model, deduced from the vehicle lateral and roll dynamics, is represented by a Takagi-Sugeno (T-S) fuzzy model. This representation is used to account for the nonlinearities of lateral cornering forces. The proposed T-S observer is designed with unmeasurable premise variables to cater for non-availability of the slip angles measurement. The proposed approach is evaluated using CarSim simulator under different driving scenarios. Simulation results show good efficiency of the proposed T-S observer and the rollover detection method.     

汽车侧翻预警及防侧翻控制

为了减少汽车侧翻事故,提出了一种基于模型的汽车侧翻预警算法以及在预警基础上的防侧翻控制算法.预警算法通过三自由度线性汽车侧翻模型计算将来一段时间内汽车横向载荷转移律的绝对值,由侧翻条件得到侧翻危险时间;控制算法根据预警时间来触发比例-微分控制器对汽车实施控制.结果表明,预警算法能够及时准确预测汽车侧翻危险,而控制方法可以更好地发挥制动器效能,防止汽车侧翻.     

考虑高速公路横向坡道转向行驶操纵稳定性的汽车轴距和轮距分析

为分析汽车轴距和轮距设计对操纵稳定性的影响,建立高速公路横向坡道转向行驶的汽车转向动力学模型,并在MATLAB/Simulink软件中建立相应的仿真模型.采用某型汽车设计轴距和轮距进行仿真,得到以不同速度在不同横向坡度道路上转向行驶时的横摆角速度、侧向加速度和质心侧偏角.根据该型汽车的转向特性和侧翻阈值评价其在高速公路...     

Modeling of rollover sequences

Safety restraint systems greatly reduce the potential injury risk during vehicle accidents. One major type of accident still remains without adequate occupant protection: Vehicle Rollover. Since rollover experiments are difficult to perform, rollover models can help to understand this type of accident. It will be shown, that already quite simple models reveal important properties of vehicle rollover. The influence of various parameter variations can be investigated. Based on a simplified modeling approach, it is possible to develop an analytic stability boundary, which helps to detect an imminent rollover. This is the base for future occupant protection systems.A more complete and complex approach of modeling, covering e.g. half and full turns, requires different strategies. To include detailed suspension systems a multi body approach becomes necessary. As an arbitrary rollover is a fully spatial movement, special assumptions like wheel-road contact do not hold for the regarded time interval. To cope with these difficulties, the simulation requires a state space machine to cover the different vehicle conditions (road contact, free flight, one side lift off). The simulation can then switch between the different model structures. With this approach, classical multi-body vehicle models can be extended by special rollover models to gain insight in the mechanisms causing vehicle rollover.     

驾驶员在环的SUV防侧翻控制器实时仿真设计

运用驾驶员在回路实时仿真系统设计SUV汽车防侧翻差动制动控制器并验证其有效性和可靠性。根据驾驶员的逻辑判断,得到理想的汽车行驶状态,当汽车行驶偏离理想值时,用控制系统来纠正SUV的横摆力矩。仿真实验在加拿大安省理工大学的汽车模拟器上进行,通过Fishhook和双移线工况对设计的控制器性能进行研究分析,对比控制前后对汽车侧向稳定性能的改善效果。仿真结果表明,所设计的控制器能有效提高汽车侧向稳定性和可操纵性。     

An investigation into vehicle rollover prevention by coordinated control of active anti-roll bar and electronic stability program

This paper presents a method for designing a controller that uses an active anti-roll bar (AARB) and an electronic stability program (ESP) for rollover prevention. ESP with longitudinal speed control (LSC) can carry out active braking to reduce vehicle speed and lateral acceleration to prevent a rollover. To enhance the rollover prevention capability of the ESP, an AARB is adopted. The controller for the AARB was designed based on linear quadratic (LQ) static output feedback (SOF) control methodology, which attenuates the effect of lateral acceleration on the roll angle and roll rate by control of the suspension stroke and the tire deflection of the vehicle. Although this AARB significantly increases ride comfort and rollover prevention, it has a drawback — the vehicle loses its maneuverability. Therefore, the ESP with LSC is used to overcome this drawback. Simulations showed that the proposed method was effective in preventing a rollover.