【作者】 高有才；

【导师】 初亮；

【作者基本信息】 吉林大学 ， 车辆工程， 2008， 硕士

【摘要】 制动防抱死系统(Anti-Lock Braking System,简称ABS)作为一种有效的车辆安全装置,能够改善车辆的操纵性和制动稳定性。本文以商用车ABS为研究对象,重点是对其控制算法的研究和验证。依据V字型开发流程,完成了包括高附着、低附着、对接路面和对开路面情况下的控制算法研究;通过ABS系统动力学模型的建立及离线仿真、快速控制原型的实现及实车道路验证、以及目标代码生成并写入实车ECU进行标定,验证了所开发控制算法的有效性。快速控制原型的实现及实车道路验证,在开发过程中对控制算法进行了很好的验证及调试,并且加快了目标代码的生成及实车ECU标定工作的进行。由真实的道路试验环境取代模拟条件下的试验环境,使试验结果更具真实性,取得了很好的效果。从而使得ABS开发周期缩短,提高了开发效率。更多还原

【Abstract】 Anti-lock braking system, as a typical example of active safety device, can guarantee the vehicle handling stability and braking performance greatly when emergency braking happens, and also, the traffic safety is increased greatly. The effectiveness of ABS has been fully reflected in the traffic and is gaining more and more acceptance, moreover the installation of ABS on the vehicles in the future has become an inevitable trend. ABS abroad is relatively mature, and it has also been made much progress in our country, but its effectiveness is not very good compared with other countries. Therefore, ABS developing with independent intellectual property rights, has a great significance for enhancing vehicle safety and improving the self-development ability.This paper studies on ABS on the basis of commercial vehicle braking system, focuses on the development of practical commercial ABS control algorithm, and has done road test and actual calibration. The major research work is as follow:1. ABS development modeAir ABS has developed greatly in the field of commercial vehicle, which is composed of ECU, pressure regulator, and wheel speed sensor, and so on. ECU will send the wheel speed signals to the computing circuit, determining the state of the wheels, and send the instructions including pressure increase, pressure hold on, and pressure decrease, in order to adjust brake pressure to achieve the purpose of ABS.This paper presents the commercial vehicle ABS style based on V-Cycle, which includes: control design and offline simulation, rapid control prototyping, automatic production code, hardware-in-the-loop simulation, and calibration. This paper selected independent control, low selection control, modified individual control, and has completed the control of four-channel vehicle.2. Further study on control algorithmAt present, there are many ABS control algorithm, this paper has introduced logic threshold control, PID control, optimal control, sliding variable structure control, fuzzy control, neural network control, genetic algorithms, etc. However, in practical application the most mature control algorithm is still the logic threshold control, therefore, this paper has continued studying on the logic threshold control algorithm.Threshold includes acceleration threshold and reference slip ratio threshold, the selection of threshold has great impact on control effect. In order to obtain the ideal control effect, the selection and matching principles of threshold have been studied deeply; meanwhile, the slip ratio threshold is also important as a supplement threshold, and is essential for the reference speed. This paper presents several reference speed estimation methods, and they are applied in the process of developing.To develop control algorithms, model building and offline simulation are very important. This paper has established eight degrees of freedom kinematic model vehicle and control logic by using MATLAB/Simulink/Stateflow, completed a variety of circumstances offline simulation, which has been compared with the simulation results without ABS, at last, the control logic is verified firstly.3. Rapid control prototyping and road testThe ABS offline simulation has been completed, in accordance with the development process, and then rapid control prototyping and road test are needed. Seamless connection with the Simulink has been realized by the dSPACE software RTI, which makes control logic be RCP. With the function automatic code generation of RTW, code has been generated and downloaded to dSPACE hardware system, and then real vehicle road test has been completed with the software Controldesk. Finally the control algorithm has been validated and debugged further.4. Control logic code written and vehicle calibratedWhen RCP achieved, the target code has been generated by dSPACE/TargetLink, then the control logic code has been written based on the integrated development environment CodeWarrior, after that target code has been downloaded into the Mototala/MC9S12DP256B of ECU and the calibration has been done.Product-level code generation is the key during the process of developing products ECU, in the front work offline simulation and RCP have been completed, the C code can be generated from MATLAB/Simulink/Stateflow by TargetLink of dSPACE system. After the product-level code generation, it need to be downloaded into the ECU and then the actual road test calibration is realized, meanwhile, the ECU of real vehicle has been debugged and improved gradually to achieve the desired result.Through the study in this paper, although great effect has been achieved and control algorithm has been developed, throughout the development process of ABS, there are lots of work needed to be done. In the future, the research on braking in curve is necessary based on the straight line braking to improve the control algorithm; meanwhile faulty diagnosis system must be added in, including faults on speed sensor, ECU, solenoid valve, power, and software, etc.更多还原