23中英文雙語(yǔ)對(duì)照外文文獻(xiàn)翻譯成品 基于超聲波與單片微型計(jì)算機(jī)嵌入式系統(tǒng)開(kāi)發(fā)集成應(yīng)用的汽車(chē)防撞系統(tǒng)設(shè)計(jì)

1、<p>　　外文標(biāo)題：The Design of automobile collision avoidance system based on the integrated application of ultrasonic and single chip microcomputer embedded system development</p><p>　　外文作者：Zhang Meng, Zhang

2、 Chunyan, Xu Jiali, Zhu Yiqin</p><p>　　文獻(xiàn)出處: International Scientific Research Organization Journal,Volume02,Issue01,2017</p><p>　　英文2104單詞， 11298字符，中文3689漢字。</p><p>　　此文檔是外文翻譯成品，無(wú)需

3、調(diào)整復(fù)雜的格式哦！下載之后直接可用，方便快捷！只需二十多元。</p><p><b>　　原文</b></p><p>　　The Design of automobile collision avoidance system based on the integrated application of ultrasonic and single chip micro

4、computer embedded system development</p><p>　　Zhang Meng, Zhang Chunyan, Xu Jiali, Zhu Yiqin</p><p>　　College of Mechanical Engineering Shanghai University of Engineering Science, No.333, Longte

5、ng Road, Songjiang District Shanghai, P.R.China</p><p><b>　　Abstract</b></p><p>　　To avoid car collision, we designed an automobile collision avoidance system based on the integrated

6、 application of ultrasonic and the SCM AT89C52 embedded system development with digital display function .The system is centered on the SCM AT89C52 and utilizes the benefits of beaming and reflecting ultrasonic waves. It

7、 also adopts the non-contact measuring method to determine the distance between automobiles and other obstacles, and the SCM decides on the response. When the distance is beyond sa</p><p><b>　　Keywords

8、</b></p><p>　　The SCM AT89C52; ultrasonic distance measuring; LCD1602; automotive anti-collision; temperature measuring chip DS18B20;</p><p>　　Introductions</p><p>　　As the Ch

9、inese economy develops, more and more people own cars; as a result, traffic safety has proportionally gained more attention. Yet all kinds of traffic accidents still constantly happen, this leads to human casualties and

10、damaged properties. Since SCM has the characteristics of being compact and light, it has significant advantage in flexibility of control, power dissipation and operation; meanwhile, ultrasound is superior in beaming, ref

11、lecting and transmitting energy. Therefore, we desi</p><p>　　Integrated system design</p><p>　　The system uses the advantages of the SCM AT89C52 and the ultrasonic as two core elements of the de

12、sign. It also uses temperature compensation to further improve the accuracy of measurement. The system mainly consisted of an ultrasonic ranging module, a phonic control module, a display module and other modules. Figure

13、 1 is a flow chat that illustrates the functioning process of the system.</p><p>　　First, the SCM AT89C52 does powers on self-test (POST). Then, the SCM AT89C52 executes the given program to initiate the ult

14、rasonic measuring module and launch the ultrasound. When the ultrasound is reflected from the barrier, the SCM calculates the time difference between the moment of launching and the moment of receiving and uses the resul

15、t to calculate the distance between the automobiles and the The SCM is the essential element of this automobile anti- collision system. SCM AT89C52 has bene</p><p>　　After using the ultrasonic measuring modu

16、le to measure the distance between an automobile and a barrier, and if the distance is safe, it will be displayed on the LCD1602; if the distance is not within safety standard, the judgment system will respond and alarm

17、the driver. At the same time, the temperature measuring chip, DS18B20, will measure the temperature of the surrounding and improve the accuracy of the measurement.</p><p>　　The data is then displayed on the

18、LCD1602. The SCM also decides whether the distance is longer or shorter safety limit; if the distance is too short and there is a risk of collision, the level of port I/0 of the SCM will switch with the amplifying circui

19、t and alarm the driver through a buzzing sound.</p><p>　　The hardware design of the automobile anti- collision system based on the SCM AT89C52</p><p>　　The design of display module</p>&l

20、t;p>　　The display module is mainly consisted of the LCD1602. The LCD1602 can display 32 characters at the same time, as shown in Figure 2. After being powered on correctly, the screen will light up and display “L”, “H

21、”, current temperature, current distance and time. It makes the operation visual and makes adjusting the range of the safe distance and the time easier by displaying the current distance and time.</p><p>　　T

22、he design of audio control module</p><p>　　The audio control module is designed based on the buzzer. A buzzer is an integrated and structured pronunciation device and it can translate sound signals into acou

23、stical signals. It also makes volume adjustment easier. The audio control module is mainly designed to alarm the driver. When the value of distance is higher than the upper limit value or lowers than the lower limit valu

24、e, the level of the I/0 ports of the SCM AT89C52 reverses with the amplifying circuit to sound the buzzer. When the </p><p>　　The design of ultrasonic ranging module</p><p>　　The ultrasonic dist

25、ance measuring module (HC-SR04) is shown in Figure 3. There are four ports including Vcc, Trig (control port), Echo (receiving port) and Gnd. The normal working voltage is 5V, and it uses I0 triggers to measure the dista

26、nce. When the high level is higher than 10us, the module launches 40KHZ square wave and it detects echo automatically. By calculating the time different between launching and receiving, it determines the distance between

27、 the automobile and the barrier. It then </p><p>　　The design of the temperature measuring module</p><p>　　The temperature measuring module is consisting of temperature measuring chip DS18B20. T

28、he range of measurement is -55℃ to +125℃ and the accuracy can reach ±2℃.</p><p>　　Ultrasonic distance measuring calculates the time difference between the launching and receiving moment to determine the

29、 distance between the automobile and the barrier, yet the speed of ultrasonic sound wave can be greatly influence by temperature. Therefore, the design of temperature measuring module is used to compensate the possible d

30、eviation due to surrounding temperature and improve the accuracy of measurement.</p><p>　　The software design of the automobile anti- collision system based on the SCM AT89C52</p><p>　　The softw

31、are design is coded with the C programming language, which has high functionality and readability. C programming language is flexible and can be applied to many kinds of operating systems and types. It also has the benef

32、its of being high in portability and grammar flexibility.</p><p>　　The software design of the automobile anti-collision system based on the SCM AT89C52 is consisted of the LCD display routine, the interrupti

33、on subroutine, the ultrasonic ranging program, the alarm subsystem and others. The design of the main program flow chat is illustrated in Figure 4.</p><p>　　Principle and function of the system</p>&l

34、t;p>　　Main working principle of the system</p><p>　　This system mainly uses the AT89C52 monolithic integrated circuit to calculate the time difference between emitting ultrasound and receiving the reflect

35、ed soundwave, where the result is used to determine the distance between the vehicle and the barrier. When the distance is shorter than the range of the safe distance, the buzzer alarm will ring to alert the driver.</

36、p><p>　　At the same time, we have to consider:</p><p>　　(1)The speed of ultrasonic wave propagation is mostly effected by surrounding temperature; therefore, the temperature should be compensated a

37、nd the acoustic velocity should be checked/</p><p>　　(2)In the course of driving, the road condition is complex, and the road surface can be wet and slipper.</p><p>　　(3)We should also consider

38、the vehicle braking deceleration, driver reaction time in the design of the response to the decision system to reduce the possibility of a false alarm.</p><p>　　Based on these three factors the formula（1）&am

39、p;（2） of ultrasonic distance measurement is given below</p><p>　　---The distance between the vehicle and the obstacle (m)</p><p>　　---Ultrasonic distance (m)</p><p>　　---Ultrasonic

40、velocity at the current temperature (m/s)</p><p>　　---current degree centigrade (℃)</p><p>　　---The time difference between the ultrasonic wave and the reflected wave (s)</p><p>　　-

41、--set the safety range (m)</p><p>　　---current car driving speed (m/s)</p><p>　　---Braking coordination time (s)</p><p>　　---Driver’s Critical reaction time to moving target (s)<

42、/p><p>　　---Braking deceleration (m/s2) </p><p>　　When ，Current driving status is in a safe state；</p><p>　　When ，The current driving state is in a danger

43、ous state, then the alarm give alert.</p><p>　　The function of the system</p><p>　　(1)Turn on system switch –when the red light is lit, it indicates the system has begun to work. The ultrasonic

44、ranging module measures the distance between the vehicle and the obstacle. The AT89C52 microcontroller is used to calculate the time difference between the ultrasonic wave and the reflected wave and determine distance be

45、tween the vehicle and the obstacle.</p><p>　　(2)The upper and lower limits of the distance can be altered through adjusting the button 2 and button 3. The “L” on the LCD1602 LCD screen indicates the lower li

46、mit of the set value, and the "H" shows the upper limit of the distance. When the calculated distance is below the set lower limit or higher than the set upper limit, the buzz will sound to give alert.</p>

47、;<p>　　(3)The system has a DS1302 clock chip, which allows the system to display the time in the LCD1602 LCD screen. Through using button 4, the time can be adjusted. Incorporating the button batteries with the cl

48、ock chip DS1302 allows it to store data about time. Even after the power is cut off and then reconnected, it will retain the date about current time.</p><p>　　(4)The system also includes the DS18B20 temperat

49、ure measurement chip, which measures the surrounding temperature and shows it on the LCD1602 LCD display. Through compensating the temperature and checking the sound velocity, it can improve the precision of the ultrason

50、ic ranging system.</p><p>　　(5)There are 5 buttons on the mainboard. The blue button controls the system to turn on or off power. When the system is on, the red light lights up. The remaining "button 1&

51、quot;, "button 2", "button3", "button 4" can control the upper limit of the value of the distance, the lower limit of the value of the time, and the state of entry and exit. Figure 5 shows t

52、he components of the system.</p><p>　　System experimental tests</p><p><b>　　Tests</b></p><p>　　Test the designed system. In the experiment, set the lower limit of measur

53、ement range L=0.06m and the upper limit H=3.50m. Experimental tests are shown in figure 6.</p><p>　　Data recording and processing of C system experiment</p><p>　　The experimental data are shown

54、in table 1:</p><p>　　The data in Table 1 are shown in Figure 8 through the Excel fitting line chart:</p><p>　　Experimental analysis</p><p>　　The experiment consisted of about 30 tri

55、als and the relative uncertainty was about 1.2%. Figure 7 shows a part of the data. When the measured distance is less than 300cm, the detected</p><p>　　distance and the actual distance have deviation within

56、 2cm.When the detection distance is more than 300cm, the distance between the measured distance and the actual distance is larger than the effective detection range.</p><p>　　Experimental conclusions</p&g

57、t;<p>　　Based on the data obtained from the experiment, the detection range of the system is from 2cm to 300cm; and the measurement error of the system is within ±2cm. The measurement accuracy of the system i

58、s high.</p><p>　　Conclusions</p><p>　　The automobile collision avoidance system with digital display function is based on the design of SCM AT89C52 and the ultrasonic distance measurement. With

59、the non-contact measurement method, the ultrasonic signal is extracted and the distance can be calculated automatically. Detection range is from 2cm to 300cm and the detection error can be accurately controlled within &#

60、177;2cm. When the driving distance of the vehicle is beyond the range of the set safety distance (less than the set lower limit o</p><p><b>　　Reference</b></p><p>　　[1]Chen Guangwu,

61、Hou Dezao,,Li Xiaoxia , et al. A practical model for calculating the safety distance of highway [J]. Ergonomics, 2001 (in Chinese)</p><p>　　[2]Lu Erhong . Special integrated circuit design and electronic des

62、ign automation[M]. Beijing: Tsinghua University press, 2004</p><p>　　[3]Gong Yunxin . C language development technology[M].</p><p>　　Tsinghua University press, 2006.10</p><p>　　[4]H

63、e Hong, editor in chief single chip microcomputer principle and interface technology[M]. Beijing: National Defense Industry Press. 2006.07</p><p>　　譯文:基于超聲波與單片微型計(jì)算機(jī)嵌入式系統(tǒng)開(kāi)發(fā)集成應(yīng)用的汽車(chē)防撞系統(tǒng)設(shè)計(jì)</p><p>　　

64、作者：張萌，張春燕，徐佳麗，朱益勤</p><p>　　單位：中國(guó)上海松江區(qū)龍騰路3333號(hào)上海工程技術(shù)大學(xué)機(jī)械工程學(xué)院</p><p>　　期刊出處：國(guó)際科學(xué)研究組織期刊</p><p><b>　　發(fā)表時(shí)間：2017</b></p><p>　　期卷信息：第二卷第一期</p><p>　　起始

65、頁(yè)碼：第8頁(yè)至第12頁(yè)</p><p><b>　　摘要</b></p><p>　　為了防止汽車(chē)發(fā)生碰撞，我們?cè)O(shè)計(jì)了一種基于超聲波集成應(yīng)用的汽車(chē)防碰撞系統(tǒng)，還開(kāi)發(fā)一種具有數(shù)字顯示功能的單片機(jī)AT89C52嵌入式系統(tǒng)。該系統(tǒng)以單片機(jī)AT89C52為核心，利用了超聲波發(fā)射和反射的優(yōu)點(diǎn)。 它還采用非接觸式測(cè)量方法來(lái)確定汽車(chē)與其他障礙物之間的距離，它是由單片微型計(jì)算機(jī)來(lái)決定

66、響應(yīng)的。 當(dāng)距離超出安全限制時(shí)，系統(tǒng)通過(guò)蜂鳴器對(duì)駕駛員進(jìn)行報(bào)警，有效防止因?yàn)槠隈{駛和視線(xiàn)模糊而造成碰撞事故。</p><p><b>　　關(guān)鍵詞</b></p><p>　　單片微型計(jì)算機(jī)AT89C52; 超聲波測(cè)距;LCD1602; 汽車(chē)防撞; 溫度測(cè)量芯片DS18B20;</p><p><b>　　引言</b>&l

67、t;/p><p>　　伴隨著中國(guó)經(jīng)濟(jì)的快速發(fā)展，越來(lái)越多的人擁有了汽車(chē)，因此，交通安全已逐年受到了人們更多的關(guān)注。但各種交通事故仍在不斷發(fā)生，這造成人員傷亡和財(cái)產(chǎn)損失。由于單片機(jī)具有體積小、重量輕等特點(diǎn)，在控制、功耗和運(yùn)行的靈活性方面具有顯著優(yōu)勢(shì);同時(shí)，超聲波在發(fā)光、反射和傳輸能量方面更勝一籌。因此，我們?cè)O(shè)計(jì)了一款基于超聲波集成應(yīng)用的汽車(chē)防撞系統(tǒng)和采用數(shù)字顯示的單片機(jī)AT89C52嵌入式系統(tǒng)開(kāi)發(fā)模塊。該系統(tǒng)采用非接觸

68、式測(cè)量方法，它可以提取超聲波信號(hào)并自動(dòng)計(jì)算距離。當(dāng)兩車(chē)之間的距離小于安全限制時(shí)，系統(tǒng)會(huì)發(fā)出嗡嗡聲，警示駕駛員并有效防止碰撞。</p><p><b>　　集成系統(tǒng)設(shè)計(jì)</b></p><p>　　該系統(tǒng)利用了單片機(jī)AT89C52和超聲波的優(yōu)點(diǎn)作為設(shè)計(jì)的兩個(gè)核心元素。它還使用溫度補(bǔ)償來(lái)進(jìn)一步提高測(cè)量的準(zhǔn)確性。該系統(tǒng)主要由超聲波測(cè)距模塊、聲控模塊、顯示模塊等模塊組成。圖1

69、是說(shuō)明系統(tǒng)運(yùn)行過(guò)程的流程圖。</p><p>　　單片機(jī)通電自檢（POST）→超聲波測(cè)距→是否在限制的范圍之內(nèi)→如果是則顯示距離并發(fā)出警報(bào)提示→如果沒(méi)有超出范圍則顯示距離→完成</p><p>　　圖一 系統(tǒng)工作運(yùn)行流程圖</p><p>　　首先，第一步是單片機(jī)AT89C52通電自檢（POST）。然后，單片機(jī)AT89C52執(zhí)行已知的程序啟動(dòng)超聲波測(cè)量模塊并啟

70、動(dòng)超聲波。當(dāng)超聲波從屏障反射時(shí)，單片機(jī)計(jì)算發(fā)射時(shí)刻與接收時(shí)刻之間的時(shí)間差，并使用結(jié)果計(jì)算汽車(chē)與汽車(chē)之間的距離。單片機(jī)是這種汽車(chē)防碰撞的基本要素系統(tǒng)。單片機(jī)AT89C52具有諸如其32個(gè)I / O端口和超過(guò)1000次劃傷壽命的優(yōu)點(diǎn)。我們可以充分利用結(jié)構(gòu)，靈活設(shè)計(jì)代碼，實(shí)現(xiàn)測(cè)量障礙物距離、自動(dòng)計(jì)算距離和發(fā)出指令的功能。</p><p>　　使用超聲波測(cè)量模塊測(cè)量汽車(chē)與障礙物之間的距離后，如果距離安全，則顯示在LCD1

71、602上;如果距離不在安全標(biāo)準(zhǔn)范圍內(nèi)，判斷系統(tǒng)會(huì)對(duì)駕駛員進(jìn)行響應(yīng)和報(bào)警。同時(shí)，溫度測(cè)量芯片DS18B20將測(cè)量周?chē)鷾囟炔⑻岣邷y(cè)量精度。</p><p>　　數(shù)據(jù)然后顯示在LCD1602上。單片機(jī)還決定距離是安全限制距離是更長(zhǎng)還是更短;如果距離太短并存在碰撞風(fēng)險(xiǎn)，單片機(jī)的I / O端口電平將隨放大電路切換，并通過(guò)蜂鳴聲報(bào)警。</p><p>　　基于單片機(jī)AT89C52的汽車(chē)防碰撞系統(tǒng)硬件設(shè)

72、計(jì)</p><p><b>　　顯示模塊的設(shè)計(jì)</b></p><p>　　顯示模塊主要由LCD1602組成。 LCD1602可同時(shí)顯示32個(gè)字符，如圖2所示。正確開(kāi)機(jī)后，屏幕將亮起并顯示“L”，“H”，也就是當(dāng)前溫度，當(dāng)前距離和時(shí)間。通過(guò)顯示當(dāng)前的距離和時(shí)間，使操作變得可視化并且使得安全距離和時(shí)間的范圍更容易調(diào)整。</p><p>　　下限值

73、 上限值 溫度</p><p>　　當(dāng)前距離 當(dāng)前的時(shí)間</p><p>　　圖二 LCD1602顯示模塊 </p><p><b>　　音頻控制模塊的設(shè)計(jì)</b></p><p>　　

74、音頻控制模塊是基于蜂鳴器而設(shè)計(jì)的。蜂鳴器是一種集成式和結(jié)構(gòu)化的發(fā)音設(shè)備，它可以將聲音信號(hào)轉(zhuǎn)換為聲學(xué)信號(hào)。它也使音量調(diào)節(jié)更加便捷容易。音頻控制模塊主要用于警告和提醒駕駛員。當(dāng)距離值高于上限值或低于下限值時(shí)，單片機(jī)AT89C52的I / O端口的電平與放大電路會(huì)反向向蜂鳴器發(fā)出提示。當(dāng)距離安全時(shí)，蜂鳴器停止發(fā)出提醒警告的聲音。</p><p>　　超聲波測(cè)距模塊的設(shè)計(jì)</p><p>　　超聲

75、波距離測(cè)量模塊（HC-SR04）如圖3所示。它是由四個(gè)端口包括Vcc、Trig（控制端口），Echo（接收端口）和GND來(lái)組成的。正常工作電壓為5伏，并使用I0觸發(fā)器測(cè)量距離。當(dāng)最高電平高于10us時(shí)，模塊啟動(dòng)40千赫茲方波并自動(dòng)檢測(cè)回波。通過(guò)計(jì)算發(fā)射和接收之間的時(shí)間差異，確定汽車(chē)與障礙物之間的距離。然后分析距離是否安全，并決定是否需要進(jìn)行警報(bào)提示。</p><p>　　+5伏 接收端口信號(hào)輸入

76、 接收端口信號(hào)輸出 GND </p><p>　　圖三 超聲波測(cè)距模塊</p><p><b>　　溫度測(cè)量模塊的設(shè)計(jì)</b></p><p>　　溫度測(cè)量模塊由溫度測(cè)量芯片DS18B20而組成的。測(cè)量范圍為-55攝氏度至+ 125攝氏度，精度可達(dá)±2攝氏度。</p><p>　　超聲波距離測(cè)量計(jì)算發(fā)

77、射時(shí)和接收時(shí)刻之間的時(shí)間差，以確定汽車(chē)與屏障之間的距離，但超聲波的速度可能受溫度的影響很大。因此，溫度測(cè)量模塊的設(shè)計(jì)用于補(bǔ)償由于周?chē)鷾囟仍斐傻目赡芷睿⑻岣邷y(cè)量的準(zhǔn)確性。</p><p>　　基于單片機(jī)AT89C52的汽車(chē)防碰撞系統(tǒng)軟件設(shè)計(jì)</p><p>　　軟件設(shè)計(jì)采用C編程語(yǔ)言編寫(xiě)，具有很高的功能和可讀性。 C編程語(yǔ)言具有靈活性，可以應(yīng)用于多種操作系統(tǒng)和類(lèi)型。它還具有高度便攜性和語(yǔ)

78、法靈活性的優(yōu)點(diǎn)。</p><p>　　基于單片機(jī)AT89C52的汽車(chē)防撞系統(tǒng)的軟件設(shè)計(jì)由LCD顯示程序、中斷子程序、超聲波測(cè)距程序、報(bào)警子系統(tǒng)等組成。主程序流程圖的設(shè)計(jì)如圖4所示。</p><p><b>　　系統(tǒng)原理和功能</b></p><p><b>　　系統(tǒng)的主要工作原理</b></p><p&

79、gt;　　該系統(tǒng)主要使用AT89C52單片機(jī)計(jì)算發(fā)射超聲與接收反射聲波之間的時(shí)間差，其中結(jié)果用于確定車(chē)輛與障礙物之間的距離。當(dāng)距離小于安全距離范圍時(shí)，蜂鳴器報(bào)警會(huì)響鈴以提醒駕駛員。</p><p>　　同時(shí)，我們還必須考慮到：</p><p>　?。?）超聲波傳播的速度主要受周?chē)鷾囟鹊挠绊?因此，因此要考慮到補(bǔ)償溫度并檢查聲速。</p><p>　　（2）在行駛過(guò)程

80、中的路況復(fù)雜性以及路面濕滑等特殊情況。</p><p>　?。?）我們還應(yīng)該考慮車(chē)輛制動(dòng)減速度、駕駛員反應(yīng)時(shí)間，以及在設(shè)計(jì)響應(yīng)決策系統(tǒng)時(shí)減少發(fā)出虛假警報(bào)提示的可能性。</p><p>　　基于這三個(gè)因素，下面給出超聲波測(cè)距公式（1）和（2）</p><p>　　圖四 程序流程圖</p><p>　　啟動(dòng)→單片機(jī)自動(dòng)監(jiān)測(cè)→發(fā)出超聲波觸發(fā)脈

81、沖→是否發(fā)出回聲→對(duì)子程序進(jìn)行解釋→距離的計(jì)算→是否在安全范圍之內(nèi)→顯示測(cè)試距離→結(jié)束</p><p>　　d---表示車(chē)輛與障礙物之間的距離（米）</p><p>　　s---表示超聲波距離（米）</p><p>　　v0---表示當(dāng)前溫度下的超聲波速度（米/每秒）</p><p>　　B---表示當(dāng)前攝氏度（攝氏度）</p>

82、<p>　　t---表示超聲波與反射波的時(shí)間差（秒）</p><p>　　D---表示設(shè)置安全范圍（米）</p><p>　　v---表示當(dāng)前車(chē)輛行駛速度（米/每秒）</p><p>　　td---表示制動(dòng)協(xié)調(diào)時(shí)間（秒）</p><p>　　tf---表示駕駛員對(duì)移動(dòng)目標(biāo)的臨界反應(yīng)時(shí)間（秒）</p><p>

83、;　　a---表示制動(dòng)減速度（米/每秒）</p><p>　　當(dāng)d>D，當(dāng)前駕駛狀態(tài)處于安全狀態(tài);</p><p>　　當(dāng)d<D，當(dāng)前駕駛狀態(tài)處于危險(xiǎn)狀態(tài)時(shí)，警報(bào)器會(huì)發(fā)出警報(bào)提示。</p><p><b>　　系統(tǒng)的功能</b></p><p>　　（1）打開(kāi)系統(tǒng)開(kāi)關(guān) - 紅燈亮?xí)r表示系統(tǒng)已開(kāi)始工作。超聲波測(cè)

84、距模塊用語(yǔ)測(cè)量車(chē)輛與障礙物之間的距離。 AT89C52單片機(jī)用于計(jì)算超聲波和反射波之間的時(shí)間差，并確定車(chē)輛與障礙物之間的距離。</p><p>　　（2）通過(guò)調(diào)整按鈕2和按鈕3可以改變距離的上限值和下限值。LCD1602 LCD屏幕上的“L”表示設(shè)定值的下限值，“H”表示距離的上限值。當(dāng)計(jì)算出的距離低于設(shè)定的下限值或高于設(shè)定的上限值時(shí)，嗡嗡聲將發(fā)出警報(bào)。</p><p>　?。?）該設(shè)計(jì)系

85、統(tǒng)有一個(gè)DS1302時(shí)鐘芯片，允許系統(tǒng)在LCD1602 LCD屏幕上顯示時(shí)間。通過(guò)使用按鈕4，可以調(diào)整時(shí)間。將電池按鈕與時(shí)鐘芯片DS1302結(jié)合使用，可以存儲(chǔ)有關(guān)時(shí)間的數(shù)據(jù)。即使電源切斷后重新連接，它仍會(huì)保留當(dāng)前時(shí)間和日期。</p><p>　?。?）該設(shè)計(jì)系統(tǒng)還包括DS18B20溫度測(cè)量芯片，用于測(cè)量周?chē)鷾囟炔⑵滹@示在LCD1602 LCD顯示屏上。通過(guò)補(bǔ)償溫度和檢測(cè)聲速，可以提高超聲波測(cè)距系統(tǒng)的精度。<

86、;/p><p>　?。?）主板上有5個(gè)按鈕。藍(lán)色按鈕控制系統(tǒng)打開(kāi)或關(guān)閉電源。系統(tǒng)打開(kāi)時(shí)，紅色的燈亮起。剩余的“按鈕1”，“按鈕2”，“按鈕3”，“按鈕4”可以分別控制距離值的上限、時(shí)間值的下限以及進(jìn)入時(shí)和退出時(shí)的狀態(tài)。圖5顯示了系統(tǒng)的組件。</p><p>　　圖五 系統(tǒng)構(gòu)件組成圖</p><p><b>　　系統(tǒng)實(shí)驗(yàn)測(cè)試</b></p&

87、gt;<p><b>　　圖六 系統(tǒng)測(cè)試</b></p><p>　　測(cè)試所設(shè)計(jì)的系統(tǒng)。在實(shí)驗(yàn)中，將測(cè)量范圍的下限值設(shè)為L(zhǎng) = 0.06米，上限值H = 3.50m。 圖6顯示了實(shí)驗(yàn)測(cè)試。</p><p>　　數(shù)據(jù)記錄和C系統(tǒng)實(shí)驗(yàn)處理</p><p>　　實(shí)驗(yàn)數(shù)據(jù)如表1所示：</p><p>　　表一

88、 測(cè)量距離以及報(bào)警提示測(cè)試記錄</p><p>　　實(shí)驗(yàn)次數(shù) 實(shí)際距離 檢測(cè)到的距離 是否報(bào)警提示</p><p>　?。▎挝唬好祝?（單位：米） （not表示否，yes表示是）</p><p>　　圖七 實(shí)驗(yàn)數(shù)據(jù)記錄</p><p>　　表一中的數(shù)據(jù)是通過(guò)Excel配件折線(xiàn)圖:來(lái)顯示在圖八中&

89、lt;/p><p>　　圖八 實(shí)驗(yàn)數(shù)據(jù)折線(xiàn)圖 藍(lán)色線(xiàn)代表實(shí)際距離（米）</p><p>　　黑色線(xiàn)代表檢測(cè)到的距離（米） </p><p><b>　　實(shí)驗(yàn)分析</b></p><p>　　該實(shí)驗(yàn)由大約30次試驗(yàn)組成，它的相對(duì)不確定性約為百分之1.2。圖7顯示了一部分?jǐn)?shù)據(jù)。當(dāng)測(cè)量距離小于300厘米時(shí)，檢測(cè)到的

90、距離和實(shí)際距離在2cm以?xún)?nèi)有偏差。當(dāng)檢測(cè)距離大于300厘米時(shí)，測(cè)量到的距離與實(shí)際距離之間的距離大于有效檢測(cè)范圍。</p><p><b>　　實(shí)驗(yàn)結(jié)論</b></p><p>　　根據(jù)實(shí)驗(yàn)得到的數(shù)據(jù)，該系統(tǒng)的檢測(cè)范圍為2厘米至300厘米;測(cè)量誤差在±2厘米以?xún)?nèi)。系統(tǒng)的測(cè)量精度很高。</p><p><b>　　結(jié)論</

91、b></p><p>　　本文中設(shè)計(jì)的具有數(shù)字顯示功能的汽車(chē)防撞系統(tǒng)是基于單片機(jī)AT89C52的設(shè)計(jì)和超聲波測(cè)距。本設(shè)計(jì)采用的是非接觸式測(cè)量方法，它可以提取超聲波信號(hào)并自動(dòng)計(jì)算距離。檢測(cè)范圍從2厘米到300厘米之間，檢測(cè)誤差可精確控制在±2厘米以?xún)?nèi)。當(dāng)車(chē)輛的行駛距離超出設(shè)定的安全距離范圍（小于設(shè)定的下限值或高于設(shè)定的上限值）時(shí)，系統(tǒng)立即通過(guò)鳴響蜂鳴器來(lái)提醒警告駕駛員。該系統(tǒng)測(cè)試表明系統(tǒng)具有精度高、

92、接觸方式少、資源損失小、滯后小、運(yùn)行平穩(wěn)、成本低等優(yōu)點(diǎn)。它可以及時(shí)提醒駕駛員并實(shí)現(xiàn)避免碰撞的功能。</p><p><b>　　參考文獻(xiàn)</b></p><p>　　[1]Chen Guangwu, Hou Dezao,,Li Xiaoxia , et al. A practical model for calculating the safety distance

93、of highway [J]. Ergonomics, 2001 (in Chinese)</p><p>　　[2]Lu Erhong . Special integrated circuit design and electronic design automation[M]. Beijing: Tsinghua University press, 2004</p><p>　　[3]

94、Gong Yunxin . C language development technology[M].</p><p>　　Tsinghua University press, 2006.10</p><p>　　[4]He Hong, editor in chief single chip microcomputer principle and interface technology[