【正文】 了廣泛的應(yīng)用價(jià)值，目前已應(yīng)用于物理測(cè)量，機(jī)器人自動(dòng)導(dǎo)航以及空氣中與水下的目標(biāo)探測(cè)、識(shí)別定位等場(chǎng)合，因此，深入研究超聲的探測(cè)理論和方法具有重要的實(shí)踐意義，為了進(jìn)一步提高測(cè)量的精確度，滿足工程人員對(duì)測(cè)量精度測(cè)距量程和測(cè)距儀使用的要求，本文研制了一套基于單片機(jī)的使拱式超聲測(cè)距系統(tǒng)。因此，設(shè)計(jì)好的超聲波測(cè)距儀就顯得非常重要了。智能交通系統(tǒng)ITS是目前世界上交通運(yùn)輸科學(xué)技術(shù)的前沿技術(shù)，它在充分發(fā)揮現(xiàn)有基礎(chǔ)設(shè)施的潛力，提高運(yùn)輸效率，保障交通安全，緩解交通賭塞，改善城市環(huán)境等方面的卓越效能，已得到各國(guó)政府的廣泛關(guān)注。二是被動(dòng)式安全技術(shù)，即事故發(fā)生后的乘員保護(hù)。它安裝在汽車上，能探測(cè)企圖接近車身的行人、車輛或周圍障礙物。奔馳汽車公司對(duì)各類交通事故的研究表明：若駕駛員能夠提早1S 意識(shí)到有事故危險(xiǎn)并采取相應(yīng)的正確措施，則絕大多數(shù)的交通事故都可以避免。其較早的產(chǎn)品是用蜂鳴器報(bào)警，蜂鳴聲越急，表示車輛離障礙物越近。這些產(chǎn)品存在的主要問題是測(cè)量盲區(qū)大，報(bào)警滯后，未考慮汽車制動(dòng)時(shí)的慣性因素，使駕駛者制動(dòng)滯后，抗干擾能力不強(qiáng)，誤報(bào)也較多。能檢測(cè)前進(jìn)和倒車方向障礙物距離, 通過后視鏡內(nèi)置的中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文顯示單元顯示距離和方位, 發(fā)出一定的聲響, 起到提示和警戒的作用。完成這種功能的裝置就是超聲波傳感器，習(xí)慣上稱為超聲波換能器或超聲波探頭。首先測(cè)出超聲波從發(fā)射到遇到障礙物返回所經(jīng)歷的時(shí)間，再乘以超聲波的速度就得到二倍的聲源與障礙物之間的距離。利用超聲波檢測(cè)距離，設(shè)計(jì)比較方便，計(jì)算處理也較簡(jiǎn)單，并且在測(cè)量精度方面也能達(dá)到要求。其主要有三種測(cè)距方法：（1）相位檢測(cè)法，相位檢測(cè)法雖然精度高，但檢測(cè)范圍有限；（2）聲波幅值檢測(cè)法，聲波幅值檢測(cè)法易受反射波的影響；（3）渡越時(shí)間檢測(cè)法，渡越時(shí)間檢測(cè)法的工作方式簡(jiǎn)單，直觀，在硬件控制和軟件設(shè)計(jì)上都非常容易實(shí)現(xiàn)。中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文 超聲波測(cè)距原理 壓電式超聲波發(fā)生器原理壓電式超聲波發(fā)生器實(shí)際上是利用壓電晶體的諧振來工作的。測(cè)量脈沖到達(dá)時(shí)間的傳統(tǒng)方法是以擁有固定參數(shù)的接收信號(hào)開端為基礎(chǔ)的。結(jié)果，一種錯(cuò)誤便出現(xiàn)了——兩個(gè)擁有不同強(qiáng)度的脈沖在不同時(shí)間超過界限卻在同一時(shí)刻到達(dá)。電路的原理如圖1所示。超聲波發(fā)射持續(xù)200ms 輸出40kHz方波 超聲波的接收與處理接收頭采用與發(fā)射頭配對(duì)的UCM40R，將超聲波調(diào)制脈沖變?yōu)殡妷盒盘?hào)，經(jīng)運(yùn)算放大器ic1a和ic1b兩級(jí)放大后加至IC2,。部分源程序如下： receive1：push pswpush accclr ex1；關(guān)中斷源1jnb ，right。其部分源程序如下：RECEIVEO: PUSH PSWPUSH ACC CLR EX0。MOV A,R7 SUBB A,3CH MOV 30H,A SETB EX0。計(jì)算時(shí)間值 存儲(chǔ)結(jié)果開外部中斷0中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文第四步：設(shè)置回波放大器的所得規(guī)格輸出，假定是3v。測(cè)量過零時(shí)間與回波振幅。主程序完成初始化工作、各路超聲波發(fā)射和接收順序的控制。因此，它不僅可用于移動(dòng)機(jī)器人，還可以用在其他檢測(cè)系統(tǒng)中。(3)ferrying more time assay, crossing the time assay way of working is simple, intuitive, in hardware control and software design are very easy to principle is: from the launch emit ultrasonic detection sensor, the gas medium spread to receive sensor of time, this time is crossing the more design is the use of ultrasonic ranging the crossing the time the mobile vehicles of the application 15中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文of ultrasonic sensor is the use of ultrasound in air of directional spread and solid reflective characteristics(pwave)and by receiving their launch ultrasonic reflecting signal, according to the ultrasonic issued and echo receiving the Windows and propagation speed, calculate transmission distance, thus obtains the obstacles to vehicle （論文）譯文 principle of ultrasonic distance measurement the principle of piezoelectric ultrasonic generatorPiezoelectric ultrasonic generator is the use of piezoelectric crystal resonators to generator, the internal structure as shown, it has two piezoelectric chip and a resonance it’s two plus pulse signal, the frequency equal to the intrinsic piezoelectric oscillation frequency chip, the chip will happen piezoelectric resonance, and promote the development of plate vibration resonance, ultrasound is , if the two are not interelectrode voltage, when the board received ultrasonic resonance, it will be for vibration suppression, then it bees the ultrasonic traditional way to determine the moment of the echo’s arrival is based on thresholding the received signal with a fixed threshold is chosen well above the noise level, whereas the moment of arrival of an echo is defined as the first moment the echo signal surpasses that intensity of an echo reflecting from an object strongly depends on the object’s nature, size and distance from the , the time interval from the echo’s starting point to the moment when it surpasses the threshold changes with the different intensities arriving exactly at the same tome will surpass the threshold at different stronger one will surpass the threshold earlier than the weaker, so it will be considered as belonging to a nearer The principle of ultrasonic distance measurement Ultrasonic transmitter in a direction to launch ultrasound, in the moment to launch the beginning of time at the same time, the spread of ultrasound in the air, obstracles on his way to return immediately, the ultrasonic reflected wave wave received by the reveiver immediately stop the in the air as the propagation velocity of 340m/s, according to the timer records the time t, we can calculate the distance between the launch distance barrier(s), that is:s=340t/2中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文 Ranging System for the Second Circuit DesignSystem is characterized by singlechip microputer to control the use of ultrasonic transmitter and ultrasonic receiver since the launch from time to time, singlechip selection of 8751,economicto –use, and the chip has 4K of ROM, to facilitate schematic diagram shown in。中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文參考文獻(xiàn)，.，KhuriYakub， Kino，.，“High Frequency Acoustic Wave Measurement in Air”，in Proceedings of IEEE 1983 Ultrasonic Symposium，October 312 November，1983，Atlanta，GA， Abreu，.，Ceres, Freire,T.,“Ultrasonic Ranging: Envelope Analysis Gives Improved Accuracy”,Sensor Review, ,1992,， M., Anaya, and Fritsch C.,‖Digital Signal Processing Techniques for High Accuracy Ultrasonic Range Measurement:,IEEE Transactions: Instrumentation and , August 1991, C., Cicco, ., Mortem, B., Prudenziati, M., and Taron, A., ―A Temperature Compensated Ultrasonic Sensor Operating in Air for Distance and Proxinmity Measurement‖, IEEE Trasaction on Industry Electronics, Vol, IE29 ,1982, , ., Ceres, R., Calderon, L and Freire, T., ‖Ultrasonic Ranging Gets Themal Correction‖, Sensor Review, Vol, 9 , 1989,（論文）譯文Ultrasonic ranging system design Publication title: Sensor : ABSTRACT: Ultrasonic ranging technology has wide using worth in many field, such as the industrial locale, vehicle navigation and sonar it has been used in level measurement, selfguided autonomous vehicles, fieldwork robots automotive navigation, air and underwater target detection, identification ,location and so there is an important practicing meaning to learn the ranging theory and ways improve the precision of the ultrasonic ranging system in hand, satisfy the request of the engineering personal for the precision,the bound and the usage, a portable ultrasonic ranging system based on the single chip processor was : Ultrasound r, Ranging System, Single Chip Processor With the development of science and technology, the improvement of people’s standard of living, speeding up the d