【正文】 本科畢業(yè)論文（設(shè)計、創(chuàng)作）題目： 基于超聲測距的汽車防撞系統(tǒng) 學(xué)生姓名： 學(xué)號： 所在院系： 專業(yè) 入學(xué)時間： 年 月導(dǎo)師姓名： 職稱/ 學(xué)位： 導(dǎo)師所在單位： 完成時間： 年 月I第 I 頁基于超聲測距的汽車防撞系統(tǒng)摘要 近年來，我國高速公路追尾碰撞事故頻頻發(fā)生，而汽車追尾碰撞預(yù)警系統(tǒng)在道路行車安全中具有良好的發(fā)展前景。為了減少周圍障礙物對駕駛員的干擾，幫助駕駛員感知障礙物的位置能夠提前有效的避開。因此本次設(shè)計采用超聲波測距系統(tǒng)，作為汽車的安全行駛輔助裝置，該系統(tǒng)能夠通過語言報警和更為直觀的 LED 顯示功能提醒駕駛員注意安全，提高了停車的安全。本設(shè)計的硬件部分主要由主控制電路和超聲波發(fā)射電路、接收電路電路構(gòu)成，以及輔助的顯示電路、電源電路和語音報警電路等，軟件部分則由超聲波收發(fā)子程序、計時子程序、顯示子程序及語音報警子程序等部分組成。由于超聲波在空氣中傳播速度是固定的，因此本設(shè)計由 STC89C51 單片機來計算超聲波從發(fā)射到被接收的往返時間，從而計算出傳輸距離實現(xiàn)實時測量距離的目的。該設(shè)計的電路設(shè)計部分合理簡單、操作穩(wěn)定、性能優(yōu)越、測距速度快、計算方法簡單迅速、容易達(dá)到實時監(jiān)控的目的，并且達(dá)到了工業(yè)實用上的測量誤差要求。關(guān)鍵詞：STC89C5超聲波、數(shù)碼管、語音報警II第 II 頁The automotive anticollision system based on ultrasonic distance measurementAbstract In recent years, highway rearend collision accident occurred frequently in our country, the automobile rearend collision warning system has good development prospect in road safety. Around in order to reduce obstacles to the driver39。s interference, help the location of the driver39。s perceived barriers can effectively avoid ahead of time. Therefore the design of ultrasonic ranging system, as a car39。s safety driving assist device, the system can alarm through language and more intuitive LED display to remind the driver pay attention to safety, to improve the safety of parking.Hardware part of this design is mainly posed of main control circuit and ultrasonic transmitting circuit, receiving circuit circuit position, as well as the auxiliary display circuit, voice alarm circuit and power circuit, software part by ultrasonic transceiver subprogram, timer subroutine and display subroutine and voice alarm subroutine and other parts. Due to the propagation velocity of ultrasonic wave in air is fixed, therefore this design by STC89C51 single chip microputer to calculate the roundtrip time of ultrasound from launch to be accepted, and transmission distance is calculated to achieve the purpose of realtime measuring distance. Circuit design part of the design is simple and reasonable, superior performance, stable operation range fast puting method is simple, and easy to achieve the purpose of realtime monitoring, and reached the industrial measurement error on the practical requirements.Keywords: STC89C51, ultrasonic, digital tube, voice alarmIII第 III 頁目錄第一章 緒論 ...........................................................................................................................................1 課題研究的現(xiàn)狀和發(fā)展歷史及意義 ............................................................................................1 汽車防撞系統(tǒng)的發(fā)展現(xiàn)狀 ............................................................................................................2 本課題的主要研究內(nèi)容 ................................................................................................................2第二章 超聲波測距的原理 .....................................................................................................................4 超聲波的基本理論 ........................................................................................................................4 超聲波的傳播速度 ................................................................................................................4 超聲波對聲場產(chǎn)生的作用 ....................................................................................................4 超聲波傳感器 ................................................................................................................................5 超聲波測距系統(tǒng)原理 ....................................................................................................................5 測量與控制方法 .............................................................................................................................6 控制系統(tǒng)方框圖 ............................................................................................................................6第三章 單片機主機系統(tǒng)電路 .................................................................................................................8 單片機主電路 ................................................................................................................................8 復(fù)位電路 ........................................................................................................................................93. 3 時鐘電路 .................................................................................................