摘要ECAS(electronic-controlled air suspension)是客车电子控制空气悬架系统 的简称，主要由空气弹簧、液力减振器、ECU 电控单元、储气室、空气压缩机、电磁 阀等组成。该悬架系统主要用于客车以及部分高级轿车，以提高车辆行驶过程中的平 顺性和操作的稳定性。本课题中主要研究是针对客车的不同运行状态进行底盘高度的 调节，如客车起步、低速行驶、高速行驶以及减速时对客车的底盘进行不同高度的调 节，已到达在行驶过程中车身保持适当高度，使客车更加平顺地行驶。本课题中需要 建立空气弹簧的数学模型，即空气弹簧的刚度表达式，另外还需建立空气弹簧的气路 数学模型。建立四自由度二分之一客车动力学方程，依据动力学方程搭建 MATLAB/simulink 电子仿真模型，并设计控制器针对不同的行驶状态进行车辆底盘高 度调节。最后选择飞思卡尔的 MC9S12D64 单片机作为硬件控制器，并且设计了电源电 路、车速信号采集电路、加速度信号采集电路、高度信号采集电路以及电磁阀驱动电 路。利用 C 语言进行了单片机程序的编写来达到控制策略的要求。83324

毕业论文关键词：空气悬架、MATLAB/simulink、高度调节、单片机、C 语言。

Abstract ECAS is the abbreviation of bus electronic control air suspension system, which is mainly composed of air spring, hydraulic shock absorber, ECU control unit, gas storage room, air compressor, solenoid valve and so on。 The suspension system is mainly used in buses and some advanced passenger cars to improve the ride comfort of the vehicle。 This paper focuses on the research for the bus the different operating conditions of the chassis height adjustment, such as passenger cars starting, low speed, high speed and deceleration of bus chassis are different height adjustment, has arrived in the driving process in the

body to maintain the proper height, the bus travel more smoothly。 In this project, we need to establish the mathematical model of air spring, that is the expression of the stiffness of air spring, and the mathematical model of air spring。 Four 1/2 degrees of freedom vehicle dynamics equation is established, and the MATLAB/simulink electronic simulation model is built according to the dynamic equation, and the controller is designed to adjust the height of the vehicle chassis。The final choice of fly think of Carl mc9s12d64 microprocessor as the hardware controller, and the design of the power supply circuit, speed signal acquisition circuit, the acceleration signal acquisition circuit, highly signal acquisition circuit and electromagnetic valve driving circuit。 Using C language to write the program of SCM to achieve the requirements of the control strategy。

Key words: air suspension, MATLAB/simulink, height adjustment,C。

目 录

第一章 绪论 1

1。1 ECAS 简介 1

1。1。1 简介 1

1。1。2 空气悬架分类 1

1。1。3 空气悬架的优点 2

1。1。4 空气悬架的缺点 2

1。2 空气悬架的关键技术及国内外研究现状 2

1。2。1 空气悬架的关键技术 2

1。2。2 空气悬架的发展历史及国内外研究现状 3

1。3 研究的背景和意义 4

1。4 研究的主要内容 4

第二章 空气悬架基本参数 5