汽車輪胎壓力監(jiān)測系統(tǒng)研究

2.2萬字
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摘 要
隨著我國人們生活水平的提高，汽車擁有量迅猛增長，隨之而來的行車安全問題也更顯突出。在汽車高速行駛過程中，輪胎故障是所有駕駛者最為擔心和最難預防的，也是突發(fā)性交通事故發(fā)生的重要原因。汽車輪胎壓力監(jiān)測系統(tǒng)(簡稱TPMS)主要用于在汽車行駛中實時監(jiān)測輪胎狀態(tài)，預防輪胎爆胎。為了有效的防止爆胎，減少因其造成交通事故帶來的人身傷害和財產損失，實時監(jiān)測車輛在高速行使過程中胎壓變化是極為必要的[1]。
影響信號傳輸?shù)姆€(wěn)定性和可靠性的因數(shù)有很多，無線信號傳輸?shù)姆€(wěn)定性是主要原因之一。針對該問題，本文研究了TPMS射頻系統(tǒng)：天線，發(fā)射與接受電路的基本原理。天線是發(fā)射和接收電磁波的一個重要的部件，沒有天線也就沒有無線通信。天線性能的主要參數(shù)有方向圖，方向性系數(shù)，增益，效率，輸入阻抗，駐波比，極化方式等。分析了系統(tǒng)硬件中PIC系列單片機和胎壓監(jiān)測模塊。胎壓監(jiān)測模塊整體安裝在輪胎內，主要完成輪胎壓力和溫度數(shù)據(jù)的采集、數(shù)據(jù)的初步處理以及信息的無線傳輸功能。并針對于胎壓監(jiān)測傳感器，核心微處理器rfPIC12F675，射頻發(fā)送電路，LF低頻喚醒電路，和胎壓檢測模塊原理圖進行了胎壓檢測模塊的設計。最后論文提出設計TPMS所面臨的5大挑戰(zhàn)包括組件選擇、功耗管理、介質兼容性、系統(tǒng)成本以及RF設計，這些因素也是商業(yè)成功的關鍵所在。
關鍵詞：TPMS；射頻系統(tǒng)；傳感器；低頻喚醒


Abstract
With the improvement of living standard in our country，the amount of automobiles increases rapidly，and the subsequent the auto-safe problems are becoming more prominent．During the high speed driving，the tires’troubles，which can be hardly prevented，are the drivers’chief worry，and these troubles are also the main factors of the sudden traffic accidents．So how to prevent tire explorations has become an important issue of safe driving，and it has drawn great attention of the related Departments in the recent years．
Tire pressure monitoring system(TPMS)，which is the life safeguard system of drivers and passengers，Can monitor the tire’pressure and temperature and other parameters at real time，transmit the monitoring informations to micro controller wirelessly，then alarm if tire is at low pressure or leaking to ensue the driving safety．After safe air pocket and ABS，TPMS is a new generation produce of auto safe in intemational auto field．TPMS is also a new research focus in auto electronics．
The research and development processes of a type of TPMS are presented wholely in this thesis.The TPMS’S characters、development status and its trends are introduced firstly，the basic principles and structures of this system are discussed then.Considering the performance indict and function requirements of this TPMS，the overall scheme is put forward，and how to select the main chips of this system is also mentioned here . This whole system is decomposed into two parts：hardware section and software section，the designing ideas、methods and implements of this system are depicted respectively．In the hardware section，the performance of the main chips used in this system are induced in the first place，and then the schematic circuit diagrams and the sample PCB pictures are showed，at last several problems appeared during the design of RF circuits are simply discussed；In the software section，the communication protocols are included，and then the thoughts and methods of the software design of TPMS’transmitter and receiver are described，in this section some actual software flow charts and source codes are given．Finally，the debugging、testing methods of TPMS and related testing results are depicted．
Keywords：solar energy；photoelectric detection；automatic tracking；control system


目 錄
摘 要 I
Abstract II
目 錄 IV
第一章 緒論 1
1.1 TPMS介紹 1
1.2 TPMS的產生 1
1.3 TPMS的構成 2
1.4 TPMS的種類 2
1.4.1 直接式TPMS 3
1.4.2 間接式TPMS 3
1.4.3 間接式TPMS和直接式TPMS的區(qū)別 3
1.4.4 混合式TPMS 3
1.5 TPMS系統(tǒng)的硬件組成 4
1.6 TPMS的工作原理 4
1.7 TPMS應用的必要性 5
1.8 使用TPMS的好處 5
1.9 TPMS技術的現(xiàn)狀 6
1.10 全球TPMS市場綜述 7
1.11 論文主要研究內容 8
第二章 射頻系統(tǒng)基本理論 9
2.1 天線基本理論 9
2.1.1 天線的方向圖與方向性系數(shù) 9
2.1.2 天線的增益 10
2.1.3 天線的效率 11
2.1.4 天線的輸入阻抗與駐波比 11
2.1.5 天線的極化方式 12
2.1.6 地面及周圍物體對天線性能的影響 13
2.2 發(fā)射、接收電路基本理論 17
2.2.1 發(fā)射機相關理論 17
2.2.2 接收機相關理論 21
第三章 系統(tǒng)硬件實現(xiàn) 24
3.1 PIC系列單片機簡介 24
3.2胎壓監(jiān)測模塊的設計 28
3.2.1胎壓監(jiān)測傳感器 28
3.2.2 核心微處理器rfPIC12F675 33
3.2.3 射頻發(fā)送電路 34
3.2.4 LF低頻喚醒電路 36
3.2.5 胎壓檢測模塊原理圖 37
第四章 直接胎壓監(jiān)測系統(tǒng)設計 38
4.1 組件選擇 38
4.2 功耗管理 38
4.3 介質兼容性 39
4.4 系統(tǒng)成本 39
4.5 RF設計 39
4.6 英飛凌公司的TPMS解決方案 40
第五章 總結與展望 42
5.1 總結 42
5.2展望 42
致謝 43
參考文獻 44