【正文】 e power steering， which is much superior to hydraulic power steering system. The assist torque is provided by motor directly in EPS system， whose value is controlled by ECU. EPS can save energy， improve vehicle safety， benefit environment protection， and it is a new hightech which follows modern vehicle development topic closely .In the foundation of the newest acplishment of domestic and international EPS ， this paper particularly researches the assist characteristic， control strategy and control system design， constructs the bench for EPS， develops electric control unit. In this paper， the key technique of EPS system， the assist characteristic and control strategy， are studied. Assist characteristic is analyzed theoretically and the feature parameters of straightline assist characteristic curve are studied. The simulation indicates the easy straightline assist characteristic can’t generate desired static torque boost and avoid road disturbance at the same time. So it is necessary that pensation control should be used. And， based on the assist characteristic， the control strategy of EPS is described in detail and the algorithms is designed to control the motor current also. The EPS control system consists of the controller， sensors and the signal processing circuits， the electric motor nag its driving circuits， munication circuit. 16bit named 80C196KC is the core of controller. For the purpose to realize the control strategy， software design and code piling are pleted. Under different operation condition and different control modes， motor can be controlled precisely. Key Words： electric power steering， assist characteristic， control strategy， software and hardware design目錄 III 目 錄 摘 要 ......................................................................................................................... I ABSTRACT ...................................................................................................................II 第一章 緒論 ................................................................................................................... 1 課題的背景和意義 ......................................................................................... 1 幾種動(dòng)力轉(zhuǎn)向的比較 ..................................................................................... 1 電動(dòng)助力轉(zhuǎn)向系統(tǒng)的發(fā)展歷程和研究現(xiàn)狀 .................................................... 3 國(guó)內(nèi)外 EPS 系統(tǒng)發(fā)展歷程 ................................................................... 3 各國(guó)對(duì) EPS 的評(píng)價(jià)及 EPS 發(fā)展前景 ..................................................... 3 本文的研究?jī)?nèi)容 .............................................................................................. 4 課題研究意義 ....................................................................................... 4 研究?jī)?nèi)容 ................................................................................................. 5 小結(jié) ................................................................................................................. 5 第二章 電動(dòng)助力轉(zhuǎn)向系統(tǒng)的原理與結(jié)構(gòu) ................................................................... 6 EPS 系統(tǒng)的結(jié)構(gòu) ............................................................................................. 6 EPS 系統(tǒng)的基本結(jié)構(gòu) ............................................................................ 6 EPS 系統(tǒng)的主要部件及工作原理 ................................................................... 7 電動(dòng)機(jī) ................................................................................................. 7 車速傳感器 ............................................................................................. 8 減速機(jī)構(gòu) ................................................................................................. 8 方向盤(pán)轉(zhuǎn)角、轉(zhuǎn)矩傳感器 ...................................................................... 8 電子控制單元 (EUC) ........................................................................... 10 本章小結(jié) ........................................................................................................ 10 第三 章 EPS 系統(tǒng)助力特性分析和控制策略研究 ....................................................... 11 助力特性分析 ................................................................................................ 11 汽車電動(dòng)助力轉(zhuǎn)向系統(tǒng)的受力分析 ................................................... 11 目錄 IV 轉(zhuǎn)向阻力和路感 ................................................................................... 13 EPS 助力特性曲線確定 ...................................................................... 13 EPS 系統(tǒng)控制策略的研究 ............................................................................ 17 EPS系統(tǒng)控制方法的選擇 ................................................................. 17 電動(dòng)機(jī)電流的控制方式 ...................................................................... 18 EPS系統(tǒng)各種控制模式下的電機(jī)目標(biāo)電流的確定方法 ................... 19 電動(dòng)機(jī)電流的閉環(huán)控制算法 .................................................................... 22 本章小結(jié) ......................................................................................................... 24 第四章 EPS 控制系統(tǒng)硬件實(shí)現(xiàn) .................................................................................. 26 EPS 控 制系統(tǒng)硬件總體設(shè)計(jì) ........................................................................ 26 EPS 控制系統(tǒng)硬件設(shè)計(jì) ...................................................................... 26 傳感器 ................................................................................................... 26 單片機(jī)系統(tǒng) 介紹 ................................................................................... 26 信號(hào)處理電路 ............................................................................................... 28 I/O 轉(zhuǎn)換電路 ....................................................................................... 28 A/D 轉(zhuǎn)換電路 ..................................................................................... 28 I/O 電動(dòng)機(jī)電流轉(zhuǎn)換電路 .........................................................