【作者】 王丽；

【导师】 刘玉梅；

【作者基本信息】 吉林大学 ， 载运工具运用工程， 2012， 硕士

【摘要】 随着汽车工业的迅速发展，由汽车运输所造成的交通事故也随之增加。为了降低事故的发生，汽车主动安全控制技术近年来迅速发展，并逐渐在实车上得以应用。汽车主动安全控制系统作用效果的发挥很大程度取决于轮胎附着信息的获取，路面附着系数不仅影响汽车的加速性能、制动性能，而且影响汽车的操纵稳定性。汽车高速行驶需要良好的道路附着来保证，由于天气等原因导致道路附着情况恶化，驾驶员往往因为不能及时反应而使汽车失控。因此在车辆的运行过程中，如何精确获取汽车状态信息，特别是路面附着信息已成为汽车主动安全控制系统发展首要解决的问题。附着系数主要决定于道路的材料、路况与轮胎的结构及胎压、车轮径向载荷、车辆速度、环境温度等因素。在行驶过程中，车辆自身参数如质量、转动惯量、胎压等在一般情况下具有时不变性，因此导致附着系数改变的主要因素还是路况的变化，如路面的种类、粗糙程度、潮湿泥泞情况等。国外的研究学者通过传感技术、模型参数估算及各种数据分析手段在路面状况识别方面取得了大量的成果。本文的研究宗旨在于利用汽车制动过程中能量传递及能量消耗理论，依据功率方程，初步探索利用传感器获取车辆运行信息，实时估算路面的附着系数，为车辆的主动控制提供理论与技术支持。汽车的制动性能是影响汽车行驶安全的重要因素。本文依据汽车制动过程的物理实质，提出一种基于能量法的附着系数识别方法。解决目前需要建立精确的轮胎模型和车辆动力学模型来估计路面附着系数的问题。通过分析四种不同的制动方式，选定只有摩擦制动器起作用的制动过程，即驾驶员踩下离合器踏板和制动器踏板，四个车轮同时产生制动力矩的制动方式。依据功率方程，推导出路面附着系数求解模型。为验证估算的有效性，本文在MATLAB/SIMULINK平台上建立仿真模型，通过ABS作用使附着系数稳定在峰值附着系数附近，则充分说明了所建立的附着系数模型的正确性。根据路面附着系数求解模型，本文对路面附着系数实时测试系统进行了初步研究。开发了外接式轮速独立测试系统和汽车车轮垂向载荷实时测试系统，在此基础上，结合V-BOXⅡ测试系统，开发了路面附着系数识别试验系统。并利用该系统对本文所建立的路面附着系数求解模型进行了实车试验，并采用matlab软件对试验数据进行了处理分析。试验结果表明本文所开发的路面附着系数识别试验系统能够实时检测汽车制动工况下的路面峰值附着系数，论文所建立的路面附着系数求解模型正确，可用于车辆运行状态下路面附着系数的实时测试，为实现汽车主动安全控制提供了一种可行性途径。更多还原

【Abstract】 With the rapid development of the automotive industry, traffic accidents also haveincreased by motor vehicles. to reduce accidents, the vehicle active safety controltechnology has rapidly developedt in recent years and gradually be applied in the vehicles.To a large extent, the vehicle active safety control systems depend on the tire adhesion,however, road adhesion coefficient not only affects the vehicle’s acceleration performance,braking performance, but also affects the vehicle’s handling and stability performance. Thecar needs a good road adhesion to achieve high speed. Therefore, the car is always out ofcontrol due to the deterioration of the road adhesion because of weather and other factors.Indriving state, how to accurately get the vehicle status information especially the roadadhesion has become the primary solution to promote the vehicle safety control systems.The road adhesion coefficient mainly depends on road materials, road surfaceconditions, parameters of the tire structure and tire pressure, wheel radial load, vehiclespeed, working temperature and other factors. In most cases vehicle parameters such asquality, rotational inertia and tire pressure change with time. Therefore, the main factorsleading to changes of road adhesion coefficient is road conditions, rough, wet and muddy.Foreign scholars have conducted research in the field of road adhesion coefficientidentification for many years. They also have made substantial achievements by sensingtechnology, the model parameter estimation and a variety of data analysis methods toidentify the road conditions. This study aims on the energy transfer and consumption theoryto identify the road adhesion coefficient with vehicle status sensors duringbraking.According to the power equation, the study can achieve the purpose of real-timeestimation of road adhesion coefficient, which provides theoretical and technical support forthe active control of the vehicle.The braking performance is an important factor affecting the safety of the car driving.This article proposed a method to identify adhesion coefficient based on the energy theory,to solve the problems the precise model of the tire and vehicle dynamics modelbeingestablished to estimate the road adhesion coefficient. By analysing four differentbraking modes, the article only selected the friction brake working method, which is thedriver depresses the clutch pedal and brake pedal, thus four wheels come into braking torques. According to the power equation theory, the article deduced the calculation modelof road adhesion coefficient, which applied to the friction brake only. To verify the validityof estimation in braking condition, simulation model was created by MATLAB/SIMULINK.Through the ABS effect, the adhesion coefficient stabilized at the peak, which fullyillustrated that the adhesion coefficient model is correct.Based on the model, the article has carried on the preliminary study of the roadadhesion coefficient identification system. This article developed an external independentwheel speed system and a real-time test system for vertical load testing. On thesefoundations, combined with the V-BOX II system, the road adhesion coefficientidentification test system was developed. In the standard road, the road adhesion coefficientidentification system was tested. The results showed that: The system can real-time detectthe peak of road adhesion coefficient in braking, thus the model of road adhesion coefficientis correct and can be used for real-time test of the road adhesion coefficient in vehiclerunning, providing a feasible approach for active safety control.更多还原