重型卡车建模及ABS算法研究

通过对载重车斯太尔1291．260／N56／4X2进行动力学分析，在Matlab／Simulink下建立了四轮汽车的基本制动模型和具有逻辑门限控制算法的ABS制动模型。仿真图形显示，具有ABS的制动模型，滑移率被控制在0．1～O．2范围内，轮速随车速逐渐减为零，说明基于本模型的ABS控制方法基本合理。     

气压ABS的模糊自寻优控制器设计与硬件在环验证

根据轮胎与路面间附着系数-滑移率关系曲线的单峰极值特性,将模糊自寻优控制算法应用到车辆气压ABS系统控制器的研究中,并通过硬件在环测试验证了该算法对车辆气压ABS系统的有效控制.与传统的逻辑门限值算法相比,该算法具有结构更简单,且能自适应路面变化的特点.     

基于滑模控制的滑移率-减速度混合控制方法

滑移率-减速度混合控制是一种用于线控制动系统中联合控制车轮滑移率与车轮减速度的控制方法,用于降低滑移率控制系统中测量噪声对控制效果的影响。文章对滑移率-减速度混合控制算法做出改进,考虑车速变化的变速趋近律设计一种滑模控制器。针对滑模控制器所需车轮纵向摩擦力不能直接测量的问题,文章以车轮滑移率作为状态变量设计一种基于龙伯格观测器的车轮纵向摩擦力观测器。通过Matlab与Carsim的联合仿真与改进前控制算法进行对比,仿真结果表明,改进后算法的控制效果有明显提高。     

一种基于模型的最佳滑移率计算方法

基于滑移率控制的防抱制动系统(ABS)实现的难点在于确定各种路况下的最佳滑移率。本文基于μ λ曲线的参数模型,应用Kalman滤波理论实时计算了不同路面下的最佳滑移率。根据Kalman滤波新息序列特性,设计了路面跃变监视器,解决了Kalman滤波算法在检测跃变路面时响应滞后的问题。最后通过计算机仿真,验证了基于模型的最佳滑移率估计算法在车辆防抱制动系统中的可行性和有效性。     

防抱死制动系统仿真分析

本文在分析了汽车制动过程中各部分运动和受力情况的基础上,运用Matlab/Simulink软件建立了车辆制动模型.采用基于滑移率的控制方法,用PID控制算法对单轮车辆模型进行仿真,并对仿真曲线进行分析,ABS的防抱死效果显著.     

ABS数据采集与算法仿真软件开发

为了更好地进行ABS的研究与开发，设计并不开发出ABS数据采集与算法仿专用软件。该软件提供了高速数据采集、轮速计算与滤波、参考车速和滑移率计算、轮加速度计算和防抱死制动控制逻辑分析等功能，为ABS的测试分析、研究开发提供了方便有的工具。经过仿调试和实车试验，软件实现了预期的防抱死控制效果，证明了软件中滑移率计算的正确性和防抱死制动控制逻辑设计的合理性。     

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.     

用MATLAB／SIMULINK进行车辆控制系统的设计

美国Ｍａｔｈｗｏｒｋｓ公司的动力模拟软件ＭＡＴＬＡＢ／ＳＩＭＵＬＩＮＫ是一种新型的图形建模语言，本文介绍这一系列及相应的控制工具箱，重点介绍了它在汽车控制系统方面的应用，作为两个列子，作者采用比例积微分控制（ＰＩＤ）和最优调节器的方法设计了基于车辆滑移率的制动控制系统，由此验证系统的高效建模与控制。     

基于制动轮缸压力的汽车ABS滑移率的计算

汽车ABS主要通过调节动力来控制制动滑移率，获得较高的附着利率，达到缩短制动距离，并且保持一定方向可操纵性的目的，一般的ABS是通过大量道路试验求得控制参数，实现对滑移率的控制，本文提出基于制动轮抽压力的汽车ABS制动滑移率的计算方法，并且经过实验证明了其合理性。     

防抱制动系统基于模型的最佳滑移率计算方法

提出了一种基于μ-λ曲线的近似数学模型来实现最佳滑移率的递推最小二乘算法(RLS)。应用累积求和统计控制法(CUSUM)，解决了RLS算法在检测跃变路面时响应滞后的问题。通过计算机仿真，验证了算法在车辆防抱制动系统中的可行性和有效性。     

Fuzzy Logic Traction Controllers and their Effect on Longitudinal Vehicle Platoon Systems

This paper presents two fuzzy logic traction controllers and investigates their effect on longitudinal platoon systems. A fuzzy logic approach is appealing for traction control because of the nonlinearity and time-varying uncertainty involved in traction control systems

The fuzzy logic traction controllers we present regulate brake torque to control wheel slip, which is the normalized difference between wheel and vehicle speed. One fuzzy controller estimates the peak slip corresponding to the maximum tire-road adhesion coefficient and regulates wheel slip at the peak slip. The controller is attractive because of its ability to maximize acceleration and deceleration regardless of road condition. However, we find through simulations the controller's performance degrades in the presence of time-varying uncertainties. The other fuzzy logic controller regulates wheel slip at any desired value. Through simulations we find the controller robust against changing road conditions and uncertainties. The target slip is predetermined and not necessarily the peak slip for all road conditions. If the target slip is set low, stable acceleration and deceleration is guaranteed, regardless of road condition

We also study the effect of traction control on longitudinal vehicle platoon systems using simulations. The simulations include acceleration and deceleration maneuvers on an icy road. The results indicate traction control may substantially improve longitudinal platoon performance, especially when icy road conditions exist.     

Introduction of a friction coefficient dependent on the slip in the FastSim algorithm

One of the main limitations of algorithms relating forces and creepages at the wheel/rail contact is the use of a friction coefficient independent of the slip. This paper overcomes this limitation through a modification of the FastSim algorithm (based on the Simplified Theory of Kalker). A friction law based on the local value of the slip is established and the required formulation of the local slip elsewhere in the contact area is presented. Some difficulties of the method and the solutions adopted by the authors are also presented. Finally, the achieved improvements are shown through comparison of the results obtained both with the original and the modified FastSim algorithms.     

用于车辆稳定性控制的直接横摆力矩及车轮变滑移率联合控制研究

设计基于最优控制理论的横摆力矩控制策略和适用于复杂工况的制动力分配策略;设计基于模糊控制理论的滑移率分配算法并提出使横摆力矩控制和变滑移率控制协同工作的方法;最后通过转向盘的阶跃输入和正弦输入工况验证制动力分配策略的正确性和联合控制的有效性。     

基于Matlab的ABS不同控制方式的仿真

汽车防抱制动系统（ABS）能实时控制车辆产生最佳的制动力矩,避免产生过大的车轮滑移,从而保持汽车的操纵性和稳定性。文中分别采用PID控制、逻辑开关控制两种方法对单轮汽车模型进行了模拟仿真。然后与没有ABS的情况进行对比,通过对仿真图形曲线的分析,得出ABS的防抱死效果明显。     

汽车防抱死制动系统的自抗扰控制研究

汽车防抱死制动系统(Anti-lock Braking System,ABS)的作用是确保汽车制动时行驶方向的稳定性、可靠性,但是目前仍存在非线性、时变性以及参数不确定性等问题.为保证汽车制动行驶过程中的操纵稳定性和安全性,进一步实现各工况下防抱死制动系统的优化控制,以影响整车稳定的变量滑移率为研究对象,分析所设计策略...     

面向汽车纵向安全辅助系统的路面附着系数估计方法

文中通过仿真研究探索了一种基于车轮滑移率的路面附着系数识别方法.首先讨论了有效估计驱动轮滑移率和利用附着系数的途径,然后在此基础上,提出了基于贝叶斯原理的路面附着系数估计迭代算法,并利用车辆动力学软件veDYNA对该算法进行仿真分析.结果表明,在滑移率大于代表不同路面的最小滑移率阈值的工况下,该方法能够快速、准确地捕获路面特征,满足汽车纵向安全辅助系统调整安全策略的需要.     

电动助力转向系统回正控制算法研究

提出了一种电动助力转向系统回正控制算法以提高转向盘的回正性。开发了一种基于转向盘转角估计的PID控制算法，该控制算法不需要转向盘转角或者电动机转速传感器，降低了控制系统的成本。同时，对提出的控制算法进行了仿真，并与其它回正控制算法的试验进行对比，结果证实此算法可提高转向盘的回正性和稳定性。     

Integrated control of brake pressure and rear-wheel steering to improve lateral stability with fuzzy logic

This study introduces an integrated dynamic control with steering (IDCS) system to improve vehicle handling and stability under severe driving conditions. It integrates an active rear-wheel steering control system and a direct yawmoment control system with fuzzy logic. Direct yaw-moment control is achieved by modifying the optimal slip of the front outer wheel. An 8-degree-of-freedom vehicle model was used to evaluate the proposed IDCS for various road conditions and driving inputs. The results show that the yaw rate tracked the reference yaw rate and that the body slip angle was reduced when the IDCS was employed, thereby increasing the controllability and stability of the vehicle on slippery roads. The IDCS system reduced the deviation from the center line for a vehicle running on a split m road.     

Coordinated vehicle traction control based on engine torque and brake pressure under complicated road conditions

Vehicle traction control system has been developed to enhance the traction capability and the direction stability of the driving wheels through the tyre slip ratio regulation. Under normal situations, if the tyre slip ratio exceeds a certain threshold, the slip ratio of the driving wheel is regulated by the coupled interaction of the engine torque and the active brake pressure. In order to obtain the best driving performance on a road under complicated friction conditions, the driving torque and the active brake pressure, need to be decoupled and adjusted to avoid penalisation of each other. In this paper, a coordinated cascade control method with two sliding-mode variable structure controllers is presented. In this control method, the driving wheel slip ratio is regulated by adjusting the engine torque and the wheel brake pressure. Through the sliding-mode controller, the engine torque is tuned to achieve the maximum driving acceleration and then the active brake pressure is applied to the slipped wheel for further modification of the wheel slip ratio. The advantage of this control method is that through proper regulation, the conflict between the two control inputs could be avoided. Finally, the simulation results validate the effectiveness of the proposed method.     

Robust estimation of maximum tire-road friction coefficient considering road surface irregularity

An accurate estimation of the maximum tire-road friction coefficient may provide higher performance in a vehicle active safety control system. Unfortunately, real-time tire-road friction coefficient estimation is costly and necessitates additional sensors that must be installed and maintained at all times. This paper proposes an advanced longitudinal tire-road friction coefficient estimation method that is capable of considering irregular road surfaces. The proposed algorithm uses a stiffness based estimation method, however, unlike previous studies, improvements were made by suggesting a third order model to solve problems related to nonlinear mu-slip curve. To attain the tire-road friction coefficient, real-time normalized force is obtained from the force estimator as exerted from the tire in the low slip region using the recursive least squares method. The decisive aspect of using the suggested algorithm lies in its low cost and versatility. It can be used under irregular road conditions due to its capability of easily obtaining wheel speed and acceleration values from production cars. The newly improved algorithm has been verified to computer simulations as well as compact size cars on dry asphalt conditions.