嵌入式電動車防鎖死煞車系統設計

The Design of an Embedded Anti-lock Brake System for an Electric Vehicle

陳啟成(Chi-Cheng Chen)

指導教授 ： 褚文和

國立虎尾科技大學/工程學院/機械與機電工程研究所/碩士(2010年)

摘要

本研究以模組化概念為出發點，設計出擁有即時作業系統之嵌入式行車控制器，具備有CANBus通訊介面模組、基本行駛功能模組與防鎖死煞車(ABS)功能模組等三個模組。本研究針對嵌入式系統、電磁煞車硬體、ABS控制理論與控制器設計進行了系統性的研究，並以Matlab軟體加以模擬分析。
本研究首先介紹嵌入式系統定義與防鎖死煞車系統概論，並介紹本研究之電動車所採用的輪內馬達作為控制煞車力的電磁煞車系統架構。設計一個防鎖死煞車系統的控制器，主要目標是保持一個適當的滑移率，使輪胎於緊急煞車的狀態下避免煞車鎖死，且仍然可以產生橫向控制力和維持轉向操控性，並可獲得更短的煞車距離。
為了控制煞車系統的滑移率，本研究詳細分析四分之一車輛模型動態方程式與計算滑移率公式作為模擬分析的系統模型。透過滑動模態控制器的設計技巧，求出等量控制與切換控制，以獲得滑動模態控制器的輸出，為了消除切換控制律所含之符號函數在其切換控制時會產生強烈的抖顫現象，本文所提出之控制器用飽和函數取代符號函數，以獲得較平滑的控制效果。並利用Matlab軟體模擬本文所提出的滑動模態控制器，結果顯示控制器輸出符合本研究所期望之狀態。
嵌入式行車控制器的實作，以ARM920T為晶片核心的S3C2440嵌入式系統晶片主機板為硬體架構，並以μC/OS II作為即時作業系統，以C程式語言，利用CAN Bus介面通訊技術實現本文所提出之嵌入式行車控制器，除了基本前進、後退、煞車等基本行駛功能外，還擁有CAN Bus通訊功能與ABS煞車功能。

關鍵字

嵌入式系統 ； CAN Bus ； 滑動模態控制器 ； ABS

並列摘要

Base on the modular concept, the purpose of this study is to design an embedded real-time operating system vehicle controller with a CAN Bus communication interface modules, and Anti-lock Brake System (ABS) function modules. The embedded system, the electromagnetic brake hardware, the ABS control theory, and the design of controller were studied systematically in this paper, and Matlab simulation software was used to simulate and analyze the system model.
First introduce Advances of embedded systems and explanation to the ABS working principles were. Then the system structure of the electric vehicle in this study was outlined, which front wheels are equipped with traditional hydraulic disk brake, while rear wheels with electromagnetic brakes force produced by the wheel motor. The purpose of designing an ABS controller is to ensure a proper slip ratio, so that the lock-wheel scenario can be avoided in emergency condition. In addition, the tires still have lateral force to keep steering capability and shorter brake distance can be assured even in a brake lock process.
To control the skid ratio mentioned above, the vehicle system model by utilizing a quarter vehicle model dynamic equation and skid ratio formula were thoroughly analyzed. Through the sliding mode controller design, equivalent control and switching control were found. In order to avoid the high frequency chattering phenomenon, the current study proposes that the sign function to replace by the saturation function so that a smoother control can be achieved. Using MATLAB to simulate the sliding-mode controller proposed in the current study, showed controller output gave reasonable expectation.
The hardware structure of the embedded real-time operating system vehicle controller is stated as follows. An embedded system motherboard using S3C2440 chip which is base on ARM920T core is selected as hardware structure. μC/OS was used as real-time operating system while C programming language implements the proposed ABS sliding mode control algorithm. As a result, the embedded real-time operating system vehicle controller functions can be fulfilled.

並列關鍵字

Electric Vehicle ； Anti-lock Brake System ； Sliding Mode Controller ； Embedded System

參考文獻

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