城市道路车辆排放测试与模拟

以长春市部分主干道为试验研究路段,采用一种车载排放测量仪器在实际道路上进行了单车排放试验,运用多项式回归的方法,整合车辆运行状况和排放数据,建立了单车实际道路微观排放模型。利用合作开发的基于路径的微观交通仿真系统与单车微观排放模型的有机结合,开发了一种可预测不同交通状况下交通干道排放的有效系统,并进行了仿真计算。结果表明:该系统不但可估算并预测车辆在某一路段的污染物排放水平,还可评价交通管理改进措施对车辆排放的影响。     

Model-Based Road Friction Estimation

The tire/road friction coefficient, μ, has a significant role in vehicle longitudinal and lateral control, and there has been associated efforts to measure or estimate the road surface condition to provide additional information for stability augmentation systems of automobiles. In this paper, a model based road friction estimation algorithm is proposed from easily measured signals such as yaw rate and wheel speed. For the development of the estimator, a low order vehicle model incorporated with simple but effective tire model. Field tests of the estimator using actual vehicle measurements show promising results.     

Roll-Over Prevention System for Commercial Vehicles – Additional Sensorless Function of the Electronic Brake System

Recent experiences have shown that even small-medium size passenger cars face an accident which has been connected with commercial vehicles so far: the roll-over. The roll-over is the most horrible accident type for truck drivers, since he/she does not have any indication before it happens, and consequently does not react properly. This article discusses some of the problems of the commercial vehicle stability in general, and offers a solution for detecting and avoiding roll-over by using the existing sensors and actuators of electronic brake system (EBS).     

A vehicle ABS adaptive sliding-mode control algorithm based on the vehicle velocity estimation and tyre/road friction coefficient estimations

A sliding-mode observer is designed to estimate the vehicle velocity with the measured vehicle acceleration, the wheel speeds and the braking torques. Based on the Burckhardt tyre model, the extended Kalman filter is designed to estimate the parameters of the Burckhardt model with the estimated vehicle velocity, the measured wheel speeds and the vehicle acceleration. According to the estimated parameters of the Burckhardt tyre model, the tyre/road friction coefficients and the optimal slip ratios are calculated. A vehicle adaptive sliding-mode control (SMC) algorithm is presented with the estimated vehicle velocity, the tyre/road friction coefficients and the optimal slip ratios. And the adjustment method of the sliding-mode gain factors is discussed. Based on the adaptive SMC algorithm, a vehicle's antilock braking system (ABS) control system model is built with the Simulink Toolbox. Under the single-road condition as well as the different road conditions, the performance of the vehicle ABS system is simulated with the vehicle velocity observer, the tyre/road friction coefficient estimator and the adaptive SMC algorithm. The results indicate that the estimated errors of the vehicle velocity and the tyre/road friction coefficients are acceptable and the vehicle ABS adaptive SMC algorithm is effective. So the proposed adaptive SMC algorithm can be used to control the vehicle ABS without the information of the vehicle velocity and the road conditions.     

Roll-Over Prevention System for Commercial Vehicles - Additional Sensorless Function of the Electronic Brake System

Recent experiences have shown that even small-medium size passenger cars face an accident which has been connected with commercial vehicles so far: the roll-over. The roll-over is the most horrible accident type for truck drivers, since he/she does not have any indication before it happens, and consequently does not react properly. This article discusses some of the problems of the commercial vehicle stability in general, and offers a solution for detecting and avoiding roll-over by using the existing sensors and actuators of electronic brake system (EBS).     

基于扰动观测的客车ESC自适应神经网络滑模控制

为了提高客车电子稳定性控制系统(ESC)的控制精度,针对实际车辆系统建模中存在各种非线性扰动项以及传统滑模控制(Sliding Mode Control,SMC)中抖振较大的问题,提出一种自适应神经网络滑模控制算法.基于2自由度车辆模型,首先设计一个二阶滑模(Second-order Sliding Mode,SOSM...     

四轮转向汽车自适应模型跟踪控制研究

使用单点预瞄驾驶员模型，针对确定性汽车模型探讨了４ＷＳ汽车在单移线行驶过程中后轮的最优转向控制规律。通过引入状态反馈，改善了整车的转向特性，将实际汽车的前后轮胎侧刚度及外界干扰视为有界的不确定性参数，采用自适应模型跟踪变结构控制方法，使得不确定的实际汽车模型能够很好地跟踪确定的最优理论模型，仿真结果表明该方法的可行性，控制系统能够有效地克服参数摄动及外界干扰对系统稳定性的影响。     

融合预瞄与势场栅格法的紧急避撞驾驶人模型

紧急避障工况下的驾驶人操作具有响应快且动作幅值较大的特点，传统预瞄驾驶人模型已不能适应紧急避障工况的需求，故考虑实际避撞场景开发相应的驾驶人模型就显得尤为必要。针对此种状况，基于驾驶模拟器，结合紧急避撞工况实际驾驶人操纵数据，提出了一种融合预瞄与势场栅格法的紧急避撞驾驶人模型。首先针对紧急避撞工况下车辆运动特点，建立车辆横、纵向耦合非线性动力学模型，并给出其状态空间方程描述；其次，离线仿真分析紧急避撞系统特征，并结合线性二次型最优控制，建立最优曲率预瞄+跟踪误差反馈驾驶人模型；再者，基于紧急避撞工况下真实驾驶人经验转向行为数据，开发基于势场栅格法的驾驶人模型，为进一步提高驾驶人模型对避障行驶工况的适应性，将基于势场栅格法的驾驶人模型与最优曲率预瞄+跟踪误差反馈驾驶人模型进行融合，并基于Sigmoid函数实现两者输出的权重分配；最后，针对所提出的融合预瞄与势场栅格法的驾驶人模型，开展基于避撞台架的驾驶人在环仿真试验以及实车试验。研究结果表明：在紧急避撞工况下，对比最优曲率预瞄+跟踪误差反馈驾驶人模型，融合预瞄与势场栅格法的驾驶人模型输出的转向动作与实际驾驶人行为较为接近，可在保证避障安全性的前提下，兼顾避障路径跟踪精度与车辆行驶的稳定性。     

纯电动汽车自动驾驶功能设计

针对纯电动车自动驾驶功能,设计一种利用PID算法对车辆的驱动扭矩进行控制的系统,使得车辆的实际速度与驾驶员的期望速度一致,实现车辆自动驾驶的功能。通过实车验证和调试,该控制系统具有良好的响应精度。相较于传统汽车通过控制喷油量的多少来控制车速,具有更好的鲁棒性和实时性。     

公交枢纽内多线路车辆实时调度优化方法研究

公交枢纽内多线路车辆的实时调度能够提高换乘效率,特别对于已经进行了发车优化的公交线路而某些车辆到达出现延误的情况。根据线路的延迟到达时间和换乘客流量等因素建立了公交枢纽内多线路车辆的实时调度优化问题模型,提出了基于整个系统费用最小的优化目标函数,并运用随机扰动梯度近似算法对问题进行求解。最后结合算例分析了本文方法的应用。     

基于模型预测控制的半挂汽车主动防侧倾控制方法

提出了一种半挂汽车主动防侧倾控制方法。搭建了一个七自由度动力学模型和一个三自由度参考模型;用无迹Kalman滤波的方法,来估计车辆的横向载荷转移率;确定优化目标,运用模型预测控制(MPC)理论进行最优化求解,得到各车轴的主动防侧倾力矩;在Simulink/Trucksim联合仿真环境中,进行仿真对比与分析。结果表明:在本文的MPC控制器和PID控制器作用下,半挂汽车各状态量皆收敛,且横向载荷转移率保持在0.7以内;相比于PID控制,MPC控制所需的防侧倾力矩更小更均衡,各状态量变化也更加平稳。因此,本MPC控制器在提升半挂汽车侧倾稳定性的同时具有较好的鲁棒性。     

汽车动力驱动系统传递特性实验建模

利用最小二乘辨识方法建立了汽车在特定工作条件下动力驱动系统的传递函数模型,通过模型降阶对其进行了简化,仿真对比表明模型辨识和降阶具有足够的精度。建模途径可用于汽车车速自动控制系统节气门开度控制器的开发。     

Tyre pressure monitoring using a dynamical model-based estimator

In the last few years, various control systems have been investigated in the automotive field with the aim of increasing the level of safety and stability, avoid roll-over, and customise handling characteristics. One critical issue connected with their integration is the lack of state and parameter information. As an example, vehicle handling depends to a large extent on tyre inflation pressure. When inflation pressure drops, handling and comfort performance generally deteriorate. In addition, it results in an increase in fuel consumption and in a decrease in lifetime. Therefore, it is important to keep tyres within the normal inflation pressure range. This paper introduces a model-based approach to estimate online tyre inflation pressure. First, basic vertical dynamic modelling of the vehicle is discussed. Then, a parameter estimation framework for dynamic analysis is presented. Several important vehicle parameters including tyre inflation pressure can be estimated using the estimated states. This method aims to work during normal driving using information from standard sensors only. On the one hand, the driver is informed about the inflation pressure and he is warned for sudden changes. On the other hand, accurate estimation of the vehicle states is available as possible input to onboard control systems.     

基于模糊解耦控制的车辆转向制动系统研究

车辆转向系统和制动系统之间存在着很强的速度耦合关系,造成两个系统之间的性能相互影响,使得车辆在转向制动这一工况成了汽车最危险的工况之一。本文结合实际车辆参数建立转向系统的二自由度模型和制动系统的单车轮模型,针对车辆转向制动工况设计了模糊解耦控制器,实现了车辆的转向与制动同时控制。经验证含有模糊解耦控制的车辆转向制动系统具有很好的动态控制效果,并且有很强的鲁棒性和自适应性。     

基于模糊控制的主动悬架联合仿真

在ADAMS软件中建立包含整车、人、随机路面等要素的仿真模型,使模型更接近实际。利用MATLAB软件建立控制系统,采用模糊控制的方法产生主动悬架的主动力,进行联合仿真。联合仿真的结果与实际情况相符,证明了主动悬架有助于减小汽车运行中悬架的垂直加速度,有利于提高乘坐舒适性。联合仿真的方法避免了复杂模型的动力学公式和传递函数推导,是开发车辆的一种有效的方法。     

汽车侧翻试验台非接触式防翻装置的设计开发

为保证汽车侧倾稳定角试验过程中的车辆安全,设计开发了一种用于防止试验车辆发生侧翻安全事故的非接触式防翻装置。该装置通过液压缸驱动防护支撑板,实现支撑板与侧翻试验台上的被试车辆保持一定安全距离的跟随运动,避免车辆达到侧倾稳定临界角时发生侧翻。经现场试验表明,该装置能够实现设计功能,在不影响试验结果的情况下保证车辆安全。     

利用A/T模型分析整车怠速振动性能

利用整车有限元模型计算出发动机曲轴转矩到驾驶员座椅和转向盘的加速度的传递函数,同时通过试验测量出发动机怠速时的输出转矩,因此,利用A/T模型可在汽车开发的前期较好地预测并控制整车怠速振动.最后以分析实例和试验验证了该方法在整车性能设计中的适用性和准确性.     

智能车小车转向系统的建模与仿真分析

文章依据典型的线性二自由度汽车模型结合freescale智能小车的实际转向系统建立数学模型，推导出微分方程，采用比例微分控制（PD）策略，并结合系统模型运用MATLAB进行仿真。采用比例微分控制（PD）策略对小车的转向系统的信号延时进行改进，对稳定性等方面也进行改善，达到预期的优化目的。     

基于带切换增益模糊调节的滑模控制算法的车辆电液制动系统

针对汽车线控电液制动系统建立了单轮车辆模型,研制了一种新的状态观测器对车速进行估算,试验结果表明该方法正确实用.采用切换增益模糊调节的滑模控制算法对非线性时变的车辆实施基于最佳滑移率的制动控制,在Matlab/Simulink中的仿真结果和验证试验都表明在汽车线控制动系统应用该算法是可行、有效的,在该算法的控制下汽车可获得比一般滑模控制更好的制动性能.     

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.