车电动助力转向器电控单元(ecu)的研究__毕业设计论文.doc

车电动助力转向器电控单元(ECU)的研究__毕业设计论文

摘要
电动助力系统采用电动机提供助力，具有转向力可变、路感良好、环保、耗能低和维修方便等优点，充分体现出汽车向智能化发展、满足未来安全性要求和环保要求的发展趋势。
本文在深入学习电动助力系统工作原理的基础上，设计了电动助力系统控制单元的硬件电路，研究了控制策略和算法，开发了相应的软件程序，印制了电路板，在自行搭建的试验平台上进行了实验验证。具体工作内容如下：
1. 研究了电动助力转向系统的发展和系统的基本原理；
2. 在充分考虑满足电动助力控制单元功能需求的基础上，开发了一套基于单片机80C552的电机控制方案：利用电子执行单元（ECU）实时采集信号，运用PWM技术实现对H桥和电动机进行电流闭环控制，并完成了硬件电路设计；
3. 在保证汽车的稳定性和安全性条件下，通过深入研究助力控制、回正控制和阻尼控制策略，提出了基于PID的控制算法，开发了核心控制程序；
上述研究工作实现了电动助力系统低速轻便、高速稳定的使用要求，为下一步的工程实用化奠定了先期技术基础。

关键词：电动机，PID，控制策略，PWM
 

Abstract
EPS is a kind of power steering system following the system of hydraulic, motor was adopted to offer power directly. EPS has many advantages such as adjusted power which is controlled by the automatically controlling unit，good way sense，environmental protection，low energy consumption, convenient maintenance. The development trend of intelligent vehicles, future security requirements and environmental requirements was fully represented by EPS.
In this thesis the Electronic Control Unit (ECU) and the software program of the ECU was designed, control strategies and algorithm were also studied based on the study of the operation principles of EPS. Following is the detailed process:
1. Basic components, working principle and mathematical model of Brushless DC Motor (BLDCM) were described in detail.
2. While the functions of ECU were considered, a scheme of motor control based on the high-performance microcontroller 80C552 was put forward and the ECU was designed. PWM technique was used to control H and closed loop motor current.
3. Three control strategies which are assisting mode return ability and damp mode to get a stable steering under various conditions was presented and discussed in this paper. And a control algorithm based on PID was proposed under the strategies.
The research above make the A/D acquisition program, speed signal acquisition program of the Electric power steering system come true, and t it laid a practical basis for the next preliminary technology.

Keywords: MOTOR; PID; Control Strategy; PWM
 

目录
摘要 Ⅰ
Abstract Ⅱ
目录 Ⅲ
第一章绪论 1
1.1电动助力转向系统 1
1.1.1电动助力转向系统的原理及发展 1
1.1.2 电动助力转向系统控制单元 3
1.2国内外研究现状 4
1.3课题研究的目的和意义 6
1.4本文研究内容 6
第二章助力特性和控制策略研究 8
2.1助力特性分析 8
2.1.1助力特性的概念 8
2.1.2助力特性曲线分类 9
2.2控制模式 10
2.2.1助力控制 11
2.2.2回正控制 12
2.3控制策略研究 13
2.3.1电机目标转矩的控制策略 13
2.3.2助力电机的电流控制策略 14
2.3.3控制算法 14
2.4本章小结 16
第三章硬件控制系统设计 17
3.1 EPS控制系统的总体结构 17
3.2 ECU的控制芯片 18
3.3电源电路和信号处理电路 19
3.3.1电源电路 19
3.3.2扭矩信号 20
3.3.3车速信号 21
3.4电机的控制电路和保护电路 21
3.4.1电动机的PWM调压调速原理 22
3.4.2功率开关部件的选择及其驱动电路 24
3.4.3电动机的保护电路 25
3.5故障诊断电路 26
3.6系统硬件的抗干扰性设计 27
3.7本章小结 27
第四章EPS控制软件设计 28
4.1系统控制软件概述 28
4.2 转向盘转矩信号采集子程序 29
4.3 车速信号的采集子程序 29
4.4 目标电流的确定 30
4.4.1 助力曲线与目标电流 30
4.4.2 助力特性曲线的确定 30
4.5 PWM 脉宽调制及电机控制 31
4.6 判断转向子程序 31
4.7 软件滤波设计 31
4.8 本章小结 32
结论及展望 33
致谢 35
参考文献 36
附录 38