【正文】 ay accidents. Therefore it bees an urgent necessity to develop a highperformanced Collision Warning System. In recent years, the road traffic safety situation more and more severe, traffic accidents to the family, the collective and the country has brought a huge loss, has bee a worldwide serious problem. Statistics show that, in many of the expressway traffic accident, behind 汽車防追尾控制系統(tǒng)設(shè)計 IV collision accident caused by the largest number, therefore, research and development of a kind of high performance car tracing cauda bull warning system bee urgent need. This article referred to the related reference data, according to the sports car braking process in state established a practical, simple safety distance model. This paper discusses ultrasonic ranging speed traps circuit design and software design. The highway of the automotive anticollision system research at home and abroad with the trend of the development of automobile intelligent, application of the system can guarantee the safety of the highspeed operation vehicles, improve road transportation efficiency, and has a broad prospect of application and economic prospects. This paper discusses and study a highway car crash system, this is a kind of active safety system. In normal driving, this system not alarm, when the car from driving after the distance between the set by less than a safe distance and may the collisions, the system will alarm information, remind drivers to take corresponding measures to avoid collision accident. The paper reference the domestic and foreign many car crash model and research results from two aspects of kinematics and dynamics of a detailed analysis on the automobile braking process, based on the state of motion established a practical, simple automotive anticollision early warning model. Through to the analysis of the reason behind collision accident , and puts forward the design requirements and determined the system design scheme of the system. The whole system from various kinds of sensors, data acquisition circuit, sound and light alarm circuit, liquid crystal display circuit and other ponents, detailed introduces the ultrasonic sensor and ultrasonic metering distance principle based on the single chip microputer and 52 metering distance principle. CX20206 as the core to realize the ultrasonic emitting and receiving , USES the monolithic external interrupt signal and implement a series of query this operation. In order to avoid ultrasonic probe from the launch to receive probe sensitive time, the delay receiving method. The results will be through the 1602 range liquid crystal display. Papers on the sensor system required makes analysis and parison and selection。 為 了 避 開超 聲 波 從 發(fā) 射 探 頭到 接 收 探 頭 的 “ 敏 感 時 間 ” ， 采 用 了 “ 延 時 接 收 ” 的 方 法 。 論文參考了國內(nèi)外諸多汽車防撞模型及研究成果，從動力學和運動學兩方面詳細分析了汽車的制動過程，根據(jù)汽車的運動狀態(tài)建立了比較實用、簡單的汽車防撞預(yù)警模型。文中探討了超聲波測距測速的電路設(shè)計和軟件設(shè)計。本文探討和研究了一種智能化的汽車防撞系統(tǒng)，在正常行駛時，該系統(tǒng)不報警，當自車與前車之間的距離小于所設(shè)定的安全距離并有可能發(fā)生碰撞時，該系統(tǒng)將發(fā)出報警信息并自動采取措施，以避免碰撞事故的發(fā)生。 在整個道路交通事故中，汽車追尾事故約占 70%以上，有些大的群死群傷惡性交通事故，開始是由于追尾剮蹭引起的。它是汽車上的一種主動安全裝置 , 用于汽車制動時防止車輪抱死拖滑 , 以及提高汽車制動過程中的方向穩(wěn)定性、轉(zhuǎn)向控 制能力和縮短制動距離 , 充分發(fā)揮汽車的制動效能。華北科技學院畢業(yè)設(shè)計（論文） 畢業(yè)設(shè)計 (論文 ) 汽車防追尾控制系統(tǒng) 汽車防追尾控制系統(tǒng)設(shè)計 目錄 設(shè)計總說明 ............................................................... I Introduction ........................................................... III 1 緒論 ................................................................... 1 設(shè)計目的和意義 .................................................... 1 設(shè)計內(nèi)容 .......................................................... 1 2 課題設(shè)計分析 ............................................................ 2 行車安全距離的概念 ................................................ 2 系統(tǒng)設(shè)計的總思想 .................................................. 2 設(shè)計方框圖 ........................................................ 4 3 STC89C52 單片機硬件電路設(shè)計 ............................................ 6 單片機最小系統(tǒng) .................................................... 6 最小系統(tǒng)原理圖 .............................................. 6 晶振電路 ..................................................... 7 復位電路 .................................................... 8 超聲波測速測距電路設(shè)計 ............................................ 9 幾種測距的介紹 .............................................. 9 超聲波發(fā)射電路 ............................................. 11 超聲波接收 .................................................. 13 聲光報警電路設(shè)計 ................................................. 16 報警電路 ................................................... 16 光提示電路 ................................................. 17 1602LCD 顯示電路設(shè)計 ............................................. 17 字符型液晶顯示器的顯示原理 ................................. 17 液晶 1602LCD 簡介 ........................................... 17 1602LCD 工作原理 ............................................ 19 DAC0808 控制電路設(shè)計 ............................................ 21 控制電路的工作原理 .......................................... 21 芯片 DAC0808 工作原理 ....................................... 22 華北科技學院畢業(yè)設(shè)計（論文） 穩(wěn)壓電源電路設(shè)計 ................................................ 24 穩(wěn)壓電源的技術(shù)指標 ......................................... 24 器件的選擇 ................................................. 25 穩(wěn)壓電源工作原理 ........................................... 27 STC89C52 的簡介 .................................................. 28 STC89C52 單片機的特點 ....................................... 28 STC89C52 單片機的結(jié)構(gòu) ..................................... 28 STC89C52 的管腳功能說明 ..................................... 30 4 STC89C52 單片機的軟件部分 .............................................. 33 總體流程圖 ....................................................... 33 超聲波控制及計算車距部分 ......................................... 34 控制車速度部分 ................................................... 35 5 結(jié)論 .........................................