第一篇：換熱器外文翻譯

換熱器

關(guān)鍵術(shù)語

折流板-在管殼式換熱器內(nèi)等間距排布，支撐管束，防止震動(dòng)，控制流速和流向，增大湍流程度，減少熱點(diǎn)。

管箱-安裝在管殼式換熱器入口側(cè)用于引導(dǎo)多管程換熱器管側(cè)流體流動(dòng)的裝置。冷凝器-用于冷卻和冷凝熱蒸汽的一種管殼式換熱器。

傳導(dǎo)-由分子震動(dòng)引起的通過固體即無空介質(zhì)的熱傳遞的方式。對流-在流體中由流體流動(dòng)引起的熱傳遞方式。逆流-指兩股流束沿著相反方向流動(dòng)，也稱為反流。錯(cuò)流-指兩股流束沿著彼此垂直的方向流動(dòng)。壓差-進(jìn)出口之間的壓力差；表示為ΔP，或德爾塔p。溫差-進(jìn)出口之間的溫度差；表示為ΔT，或德爾塔t。

固定管板式換熱器-用于指管板與殼體剛性固定的管殼式換熱器的術(shù)語。浮頭-指換熱器上介質(zhì)返回側(cè)管板不與殼體固定，并且設(shè)計(jì)成當(dāng)溫度升高時(shí)可在殼體內(nèi)伸長（浮動(dòng)）。

污垢-在如冷卻塔和換熱器等設(shè)備內(nèi)表面形成的，導(dǎo)致熱傳遞效率降低和堵塞。釜式再沸器-帶有蒸汽分離腔的管殼式換熱器，用于蒸餾系統(tǒng)中，為分離輕重組分提供高溫，并維持熱平衡。

層流-近乎完整的流線型流動(dòng)，液流層在平行的軌道上流動(dòng)。

多管程換熱器-一種管程流體流過管束（熱源）超過一次的管殼式換熱器平行流-指兩股流束沿著相同的方向流動(dòng)，例如，管殼式換熱器中的管側(cè)流和殼側(cè)流；也稱為并流

輻射熱傳遞-熱量在熱源和接收者之間通過電磁波傳輸。再沸器-用于加熱曾經(jīng)沸騰的液體直到液體再次沸騰的換熱器。顯熱-通過溫度的改變能夠測量或感覺到的熱量。管殼式換熱器-一種有一個(gè)圓筒殼環(huán)繞著管束的換熱器。殼側(cè)-指管殼式換熱器繞管外側(cè)的流道。參見管側(cè)。

熱虹吸再沸器-當(dāng)靜態(tài)的液體被加熱到沸點(diǎn)時(shí)會(huì)產(chǎn)生自然循環(huán)的換熱器型式。管板-管殼式換熱器管端通過滾脹、焊接、或者兩者并用的方法連接固定在其上的平板。

管側(cè)-指通過管殼式換熱器管內(nèi)的流道，參見殼側(cè)。湍流-流體在漩渦中隨機(jī)運(yùn)動(dòng)或混合。

換熱器的類型 熱量傳遞在工業(yè)過程中有非常重要作用。換熱器廣泛用于過程之間的熱量傳遞，它能夠使熱流體的熱通過熱傳導(dǎo)或?qū)α鞯姆绞絺鬟f給冷流體。換熱器為此過程提供加熱或冷卻。各種各樣的的換熱器被用于化工過程工業(yè)中。

在盤管式換熱器中，蛇管浸沒在水里或向其噴水來進(jìn)行傳熱，這種操作方式傳熱系數(shù)較低且需要較大空間，因此它最適用于用較低的熱負(fù)荷來冷凝蒸汽。套管式換熱器是采用一個(gè)管子包含在另一個(gè)管子里面的設(shè)計(jì)，管子可以是光管或外部翅片管。套管換熱器通常采用串聯(lián)使用，殼側(cè)操作壓力高至500磅/平方英寸（表壓），而管側(cè)5,000磅/平方英寸（表壓）。

管殼式換熱器有一個(gè)圓筒形殼體包在管束外面。流過換熱器的流體被稱為管側(cè)流體或殼側(cè)流體。換熱器內(nèi)有一系列折流板支撐著管束，用于引導(dǎo)流體流動(dòng)，增大流速，減少管子震動(dòng)，保護(hù)管子，并產(chǎn)生壓力降。管殼式換熱器可以分類為單程固定管板式、多程固定管板式、多程浮頭式和U型管式。固定管板式換熱器（圖7.1）的管板與殼體固定。固定管板式換熱器適用于最大溫差為200°F(93.33°C)的操作。由于熱膨脹的存在固定管板式換熱器不能超過這個(gè)溫差值。它最適合用于冷凝或加熱操作。浮頭式換熱器是為200°F(93.33°C)以上的高溫差設(shè)計(jì)的。操作過程中，一塊管板固定而另一塊管板在殼體內(nèi)“浮動(dòng)”，浮動(dòng)端未與殼體固定且可以自由膨脹。

再沸器是用于加熱曾經(jīng)沸騰的液體直到液體再次沸騰的換熱器。工業(yè)上常用的類型有釜式和熱虹吸式。

板式換熱器主要由若干個(gè)金屬板片構(gòu)成，交替排列的金屬板片是為冷熱交換設(shè)計(jì)的。兩相鄰板片的邊緣處有墊片，壓緊后可達(dá)到密封的目的。板式換熱器有冷熱流體的進(jìn)口和出口。板片和墊片的四個(gè)角孔形成了流體的分配管和匯集管，使冷熱流體逆向經(jīng)過相鄰板間的波紋流道空間，該裝置最適用于粘性和腐蝕性介質(zhì)，其傳熱效率很高。板式換熱器結(jié)構(gòu)緊湊且便于清洗，操作溫度限制在350到500°F(176.66°C到260°C)，其目的是為了保護(hù)內(nèi)部墊片，由于設(shè)計(jì)要求板式換熱器不適合于沸騰和冷凝。工業(yè)過程中的大多數(shù)液液兩相流體的交換都使用該設(shè)計(jì)。

風(fēng)冷換熱器在操作過程中不需要?dú)んw，工藝管連接在一個(gè)進(jìn)水口和一個(gè)可回程的匯流箱中，管子上可能存在翅片管或光管，翅片的作用是推動(dòng)或拉動(dòng)外界的空氣越過暴露的管子，風(fēng)冷換熱器主要應(yīng)用于高傳熱的冷凝操作。螺旋板式換熱器的特點(diǎn)是結(jié)構(gòu)緊湊，該設(shè)計(jì)使流體在媒介中形成高湍流。同其他換熱器一樣，螺旋板式換熱器有冷熱流體的進(jìn)口和出口，在內(nèi)表面實(shí)現(xiàn)熱的交換，螺旋板式換熱器還有兩個(gè)內(nèi)部腔。

管式換熱器的制造商協(xié)會(huì)通過多種設(shè)計(jì)的規(guī)范標(biāo)準(zhǔn)將換熱器進(jìn)行分類，其中包括美國機(jī)械工程師協(xié)會(huì)(ASME)的結(jié)構(gòu)代碼，公差和機(jī)械設(shè)計(jì)： ? B類，專為通用操作（經(jīng)濟(jì)和緊湊設(shè)計(jì)）

? C類，專為適度的服務(wù)和通用操作（經(jīng)濟(jì)和緊湊設(shè)計(jì)）? R類，專為惡劣的條件下（安全耐久性）

傳熱和流體流動(dòng)

傳熱的方式有熱傳導(dǎo)，熱對流，熱輻射（圖7.2），在石油化學(xué)產(chǎn)品中，煉油廠和實(shí)驗(yàn)室的環(huán)境中，這些方法需要被充分的理解，在所有的換熱器中都能發(fā)現(xiàn)熱傳導(dǎo)和熱對流過程的結(jié)合。傳熱的最佳條件是產(chǎn)品受熱或冷卻有較大的溫差（溫差越大，傳熱效果越好），高能量或高的冷卻劑流率，較大的換熱面積。

圖7.2 傳熱

傳導(dǎo)

熱傳導(dǎo)的熱量是通過固體傳遞的，例如管子，封頭，擋板，管板，翅片和殼體。這個(gè)過程發(fā)生在當(dāng)分子固體矩陣從熱源吸收熱量，由于分子在一個(gè)固體矩陣并且不能移動(dòng)，它們開始振動(dòng)，這時(shí)能量就從熱的一側(cè)轉(zhuǎn)移到冷的一側(cè)。熱對流

對流是液體中較熱部分和較冷部分之間通過循環(huán)流動(dòng)使溫度趨于均勻的過程，在液體中分子的運(yùn)動(dòng)形成電流，然后再重新分配能量，這個(gè)過程將持續(xù)進(jìn)行直到能量分布均勻?yàn)橹?，在一個(gè)換熱器中，這個(gè)過程發(fā)生在流體介質(zhì)彼此接觸進(jìn)行能量交換時(shí)。擋板的排列方式和流體的流向?qū)⒁獩Q定這個(gè)對流會(huì)發(fā)生在換熱器的各個(gè)部分。熱輻射

熱輻射最好的例子是太陽使地球變得溫暖，太陽的熱量是通過電磁波傳遞的。熱輻射是一個(gè)視線的過程，因此發(fā)射源和接收源的位置是非常重要的，在熱交換器中沒有輻射傳熱過程。層流和湍流

流體流動(dòng)的兩個(gè)主要分類是層流和湍流（圖7.3）。層式或流線型流動(dòng)流體在管內(nèi)流動(dòng)時(shí)，其質(zhì)點(diǎn)沿著與管軸平行的方向作平滑直線運(yùn)動(dòng)。此類流動(dòng)的流量很小，有很小的擾動(dòng)（旋轉(zhuǎn)和渦流）。湍流通常有很大的流速。當(dāng)流速增加時(shí)，層流模式將要改變成擾動(dòng)模式，湍流是隨機(jī)的運(yùn)動(dòng)或流體的混合。一旦湍流流動(dòng)開始，分子的運(yùn)動(dòng)速度就要加快直到流體統(tǒng)一擾動(dòng)為止。湍流流動(dòng)允許液體分子混合使其比層流流動(dòng)更容易吸收熱量。層流流動(dòng)促進(jìn)了靜電膜的發(fā)展，靜電膜是一個(gè)絕緣體。湍流流動(dòng)減少了靜電膜的厚度，提高了傳熱率。平行流和串流

換熱器可以通過不同的方式連接，最常見的串聯(lián)和并聯(lián)(圖7.4)，串流中(圖7.4)，在一個(gè)多通道的換熱器中通過管側(cè)流動(dòng)排入到第二個(gè)換熱器中，根據(jù)換熱器是如何運(yùn)行的這種排放路線可以被轉(zhuǎn)向到殼程或管程中。導(dǎo)向原則是經(jīng)過一個(gè)換熱器的流動(dòng)在它到第二個(gè)換熱器之前。在并聯(lián)流動(dòng)中工藝工程是在同一時(shí)間經(jīng)過多個(gè)換熱器。

圖7.3 層流和湍流

圖7.4 并聯(lián)和串聯(lián)流

圖7.5換熱器的串行流

換熱器的有效性

換熱器的設(shè)計(jì)通常要考慮它是如何有效的傳遞能量，污垢是一個(gè)難題，它可能使一個(gè)換熱器停止傳遞熱量，在持續(xù)的運(yùn)作期間，換熱器不能保持清潔。污垢，水銹，和過程中的沉積物的結(jié)合使換熱器內(nèi)部的傳熱受到限制。這些沉積物在殼體壁面存在，抵抗了流體流動(dòng)，減慢或停止熱量的傳導(dǎo)。一個(gè)換熱器的污垢阻力取決于被處理液體的類型，在系統(tǒng)中的數(shù)量和懸浮物的類型，對換熱器的熱分解，和液流的流速和溫度。增加流速或降低溫度可以使污垢減少，通過檢查管程內(nèi)外的壓力，殼程內(nèi)外壓力可以識(shí)別污垢。這些數(shù)據(jù)常被用來計(jì)算壓差或計(jì)算管段阻力損失，進(jìn)口，出口的壓差是不同的，作為管段阻力損失或腐蝕和侵蝕是在熱交換中存在的另一個(gè)問題，化學(xué)制品，熱量，流體流動(dòng)和時(shí)間會(huì)磨損換熱器的內(nèi)部結(jié)構(gòu)?；瘜W(xué)抑制劑被添加來防止腐蝕和結(jié)垢。這些抑制劑用來減輕腐蝕，藻類生長和礦物質(zhì)的沉積。套管換熱器

套管換熱器是一個(gè)簡單的傳熱裝置設(shè)計(jì)，套管換熱器的管內(nèi)部還有一根管子(圖7.6)。外部管道作為殼程，內(nèi)管作為管程，冷熱流體能在同一個(gè)方向流動(dòng)(并聯(lián)流動(dòng))，或相反方向流動(dòng)(逆流或?qū)α?。

流動(dòng)方向通常是相反的，因?yàn)檫@樣傳熱效率高，此效率是由于擾動(dòng)，相碰撞的顆粒，相反的氣流引起的。即使兩個(gè)液體流從未彼此直接接觸，這兩個(gè)熱能量流(冷和熱)沒有相互遇到。在每個(gè)管道內(nèi)氣流的對流混合散發(fā)熱量。

圖7.6 套管換熱器

在一個(gè)平行流式換熱器中，單相流的出口溫度接近另一單相流的出口溫度，在一個(gè)兩相逆流換熱器中，一種單相流的出口溫度接近于另一單相流的進(jìn)口溫度，因?yàn)榻档偷臏夭钚≡谄叫辛魇綋Q熱器中只能進(jìn)行少量的能量傳遞，靜電膜對管道內(nèi)熱量交換產(chǎn)生限制，就如隔熱屏障。

接近管子的液體是熱的，遠(yuǎn)離管子的液體是冷的，任何類型的湍流效應(yīng)將會(huì)打破靜態(tài)膜和傳遞能量渦流室周圍的一切，平行流不能產(chǎn)生湍流的漩渦。

套管換熱器的系統(tǒng)局限性是其可以處理流率，最有代表性的是套管換熱器的流率是很小的，低流率有利于層流流動(dòng)。夾套式換熱器

夾套式換熱器通常被使用于化工行業(yè)(圖7.7)，夾套式換熱器有兩種基本模式：套管和多管設(shè)計(jì)，夾套式換熱器的規(guī)定殼程壓力是500磅/平方英寸（表壓），管程壓力是5000磅/平方英寸（表壓）。此類換熱器得名于其不同尋常的發(fā)夾式形狀，套管設(shè)計(jì)是管內(nèi)部還有一根管子，翅片添加在管子外部可以增加熱傳遞。

這個(gè)發(fā)夾類似于管殼式換熱器，拉伸和彎曲成一個(gè)發(fā)夾。這個(gè)發(fā)夾設(shè)計(jì)有幾個(gè)優(yōu)點(diǎn)和缺點(diǎn)：它最大的優(yōu)點(diǎn)是由于U型管的形狀使其熱膨脹系數(shù)很高, 它的翅片設(shè)計(jì)同時(shí)有要求流體有一個(gè)較低的傳熱系數(shù)，管側(cè)有很高的壓力。此外它很容易安裝和清洗，其模塊化的設(shè)計(jì)很容易增加節(jié)段；或更換部件物美價(jià)廉，供應(yīng)充足。其缺點(diǎn)是并不像管殼式換熱器成本效益低并且它需要特殊的墊圈。

圖7.7 夾套式換熱器

管殼式換熱器

管殼式換熱器是在工業(yè)中最常見的一種換熱器。管殼式換熱器適用于高流量，連續(xù)操作的場合，根據(jù)流程和需要的傳熱量管子的排列方式可以發(fā)生改變，當(dāng)管側(cè)流或封頭內(nèi)流體進(jìn)入到換熱器中時(shí)兩流體彼此平行流動(dòng)。管程內(nèi)有一種流體，殼程內(nèi)有另一種流體流動(dòng)。熱量通過管壁傳遞給冷流體，熱傳遞的發(fā)生首先是熱傳導(dǎo)，其次是熱對流。圖7.8顯示的是一個(gè)單程固定封頭式換熱器。流體流進(jìn)和流出的交換器是針對特定于的液體蒸汽。在系統(tǒng)中液體從底部裝置流動(dòng)到頂部以減少或消除受到限制的蒸汽。氣體從頂部流動(dòng)到底部消除被堵塞或積累的液體，此標(biāo)準(zhǔn)既適用于管程流動(dòng)又適合于殼程流動(dòng)。板框式換熱器

板框式換熱器是高傳熱、高壓降裝置。它由一系列用壓縮螺栓固定的兩端板間的墊圈(圖 7.20 和 7.21)。平板之間的通道是為壓降和湍流流動(dòng)設(shè)計(jì)的，以為了完成高的傳熱效率。板式換熱器的 開口通常位于桿端蓋處。當(dāng)熱流體進(jìn)入熱通道時(shí)將會(huì)通過排出口被送進(jìn)交替的板之間。然后到上面的板子處。當(dāng)冷流體進(jìn)入桿端蓋處逆流的冷空氣通道時(shí)。冷流體往上流動(dòng)到平板上，熱流體通過平板向下流動(dòng)到。這個(gè)薄板將冷熱流體進(jìn)行分離，防止泄露。流體流過板子后進(jìn)入集管。平板被設(shè)計(jì)成有一系列交錯(cuò)的格子。熱量通過熱傳導(dǎo)在平板表面進(jìn)行傳熱，通過對流進(jìn)入液體。整個(gè)管板流淌冷熱流體和像個(gè)分隔管

冷熱流體在板子的兩個(gè)相對方向上平行流動(dòng)。熱流體在頂部流經(jīng)換熱器的墊圈。這個(gè)安排要考慮壓降和湍流流動(dòng) 當(dāng)流體流經(jīng)板子進(jìn)入?yún)R集箱時(shí)。冷流體的冷流體進(jìn)入板式換熱器的底部墊圈，與熱流體形成對流。采集頭位于換熱器的上部。

板框式換熱器有以下幾個(gè)優(yōu)點(diǎn)和缺點(diǎn)。他們很容易拆卸、清理、分散熱量以至于沒有熱點(diǎn)。板子很容易增加和移動(dòng)。其他的優(yōu)點(diǎn)是流體阻力小、污垢小、熱效率高。此外，如果墊圈泄露，當(dāng)泄漏到外面時(shí)，很容易更換墊圈。

圖7.20 板框式換熱器

圖7.21 板框式裝配

板子也可以防止產(chǎn)品的交叉污染。板框式換熱器可以產(chǎn)生與管殼式是換熱器相比比較小的大的湍動(dòng)，大的壓降。板框式換熱器的缺點(diǎn)是它對高溫和高壓的限制。墊圈很容易損壞和處理的液體不能兼容。

螺旋式換熱器的設(shè)計(jì)以緊湊同心為特點(diǎn)，能形成高湍流流體(圖 7.22)。這種換熱器有兩個(gè)基本類型：(1)兩側(cè)螺旋流、(2)橫向螺旋流。

第一種類型的螺旋板換熱器適用于液液流體進(jìn)行換熱，冷凝器，氣體冷卻器裝置。流進(jìn)換熱器的流體是專為逆流操作設(shè)計(jì)的。水平軸安裝使懸浮固體能夠進(jìn)行自動(dòng)清理。

圖7.22 螺旋式換熱器

第二種類型的螺旋板換熱器適用于冷凝器，氣體冷卻器、加熱器和再沸器裝置。垂直安裝為高速液體和蒸汽結(jié)合和在蒸汽混合側(cè)產(chǎn)生低壓降創(chuàng)造了極好的條件。第二種類型的螺旋板換熱器適用于高流量率能抵消低流量率的液液系統(tǒng) 風(fēng)冷換熱器

翅片熱風(fēng)機(jī)和風(fēng)冷換熱器傳熱的的方式不同。風(fēng)冷換熱器提供了一個(gè)矩陣結(jié)構(gòu)的平板或翅片管與進(jìn)口或回流管連接。當(dāng)空氣作為外部的傳熱介質(zhì)時(shí)要遠(yuǎn)離管子。翅片的這樣多種形式安排是為了形成強(qiáng)制對流，增大傳熱系數(shù)。在強(qiáng)迫氣流和誘發(fā)氣流中翅片被安裝管子的上方或下方。管子可以水平和垂直放置。風(fēng)冷換熱器可的封頭可以分類為管型箱，焊接箱，蓋板，多歧管。管型箱和焊接箱在每個(gè)管子的端板上都有防水塞。這種設(shè)計(jì)方便逐根管進(jìn)行清洗，如果泄露可以堵住，再軋制緊固管接頭。蓋板設(shè)計(jì)為所有管子提供簡易的通道。在蓋板和封頭連接處要放置墊片。這樣多樣化的類型是為高壓環(huán)境設(shè)計(jì)的。機(jī)械翅片運(yùn)用多樣的驅(qū)動(dòng)程序，在風(fēng)冷換熱器中可以發(fā)現(xiàn)普通驅(qū)動(dòng)設(shè)置，包括電動(dòng)機(jī)，壓縮齒輪，蒸汽渦輪，內(nèi)燃機(jī)，和液壓馬達(dá)。

圖7.23 風(fēng)冷換熱器

翅片葉片是由鋁和塑料組成的。鋁翅片適用于操作溫度高于300°華氏溫度(148.88°C)，而塑料翅片的操作溫度被限制在160°F和180°F之間(71.11°C, 82.22°C)。

風(fēng)冷換熱器經(jīng)常被應(yīng)用于空氣壓縮裝置中，在再循環(huán)系統(tǒng)中用于冷凝操作。這種類型的換熱設(shè)備為周圍空氣與排除的工藝流體之間提供了一個(gè)40°F(4.44°C)溫度差。比水冷換熱器構(gòu)造更簡單，維修更便宜。風(fēng)冷換熱器沒有與水相關(guān)的污染和腐蝕問題。他們有低廉的經(jīng)營成本和優(yōu)越的高溫移除(200°F or 93.33°C以上)。

他們的缺點(diǎn)是對于液體或冷凝設(shè)備有高的流體出口溫度，高的設(shè)備成本費(fèi)的限制。此外，他們在額定情況下容易失火或爆炸。

第二篇：外文翻譯

當(dāng)今時(shí)代是一個(gè)自動(dòng)化時(shí)代，交通燈控制等很多行業(yè)的設(shè)備都與計(jì)算機(jī)密切相關(guān)。因此，一個(gè)好的交通燈控制系統(tǒng)，將給道路擁擠，違章控制等方面給予技術(shù)革新。隨著大規(guī)模集成電路及計(jì)算機(jī)技術(shù)的迅速發(fā)展，以及人工智能在控制技術(shù)方面的廣泛運(yùn)用，智能設(shè)備有了很大的發(fā)展，是現(xiàn)代科技發(fā)展的主流方向。本文介紹了一個(gè)智能交通的系統(tǒng)的設(shè)計(jì)。該智能交通燈控制系統(tǒng)可以實(shí)現(xiàn)的功能有：對某市區(qū)的四個(gè)主要交通路口進(jìn)行控制：個(gè)路口有固定的工作周期，并且在道路擁擠時(shí)中控制中心能改變其周期：對路口違章的機(jī)動(dòng)車能夠即時(shí)拍照，并提取車牌號。在世界范圍內(nèi)，一個(gè)以微電子技術(shù)，計(jì)算機(jī)和通信技術(shù)為先導(dǎo)的，一信息技術(shù)和信息產(chǎn)業(yè)為中心的信息革命方興未艾。而計(jì)算機(jī)技術(shù)怎樣 與實(shí)際應(yīng)用更有效的結(jié)合并有效的發(fā)揮其作用是科學(xué)界最熱門的話題，也是當(dāng)今計(jì)算機(jī)應(yīng)用中空前活躍的領(lǐng)域。本文主要從單片機(jī)的應(yīng)用上來實(shí)現(xiàn)十字路口交通燈智能化的管理，用以控制過往車輛的正常運(yùn)作。

研究交通的目的是為了優(yōu)化運(yùn)輸，人流以及貨流。由于道路使用者的不斷增加，現(xiàn)有資源和基礎(chǔ)設(shè)施有限，智能交通控制將成為一個(gè)非常重要的課題。但是，智能交通控制的應(yīng)用還存在局限性。例如避免交通擁堵被認(rèn)為是對環(huán)境和經(jīng)濟(jì)都有利的，但改善交通流也可能導(dǎo)致需求增加。交通仿真有幾個(gè)不同的模型。在研究中，我們著重于微觀模型，該模型能模仿單獨(dú)車輛的行為，從而模仿動(dòng)態(tài)的車輛組。

由于低效率的交通控制，汽車在城市交通中都經(jīng)歷過長時(shí)間的行進(jìn)。采用先進(jìn)的傳感器和智能優(yōu)化算法來優(yōu)化交通燈控制系統(tǒng)，將會(huì)是非常有益的。優(yōu)化交通燈開關(guān)，增加道路容量和流量，可以防止交通堵塞，交通信號燈控制是一個(gè)復(fù)雜的優(yōu)化問題和幾種智能算法的融合，如模糊邏輯，進(jìn)化算法，和聚類算法已經(jīng)在使用，試圖解決這一問題，本文提出一種基于多代理聚類算法控制交通信號燈。

在我們的方法中，聚類算法與道路使用者的價(jià)值函數(shù)是用來確定每個(gè)交通燈的最優(yōu)決策的，這項(xiàng)決定是基于所有道路使用者站在交通路口累積投票，通過估計(jì)每輛車的好處(或收益)來確定綠燈時(shí)間增益值與總時(shí)間是有差異的，它希望在它往返的時(shí)候等待，如果燈是紅色，或者燈是綠色。等待，直到車輛到達(dá)目的地，通過有聚類算法的基礎(chǔ)設(shè)施，最后經(jīng)過監(jiān)測車的監(jiān)測。

我們對自己的聚類算法模型和其它使用綠燈模擬器的系統(tǒng)做了比較。綠燈模擬器是一個(gè)交通模擬器，監(jiān)控交通流量統(tǒng)計(jì)，如平均等待時(shí)間，并測試不同的交通燈控制器。結(jié)果表明，在擁擠的交通條件下，聚類控制器性能優(yōu)于其它所有測試的非自適應(yīng)控制器，我們也測試?yán)碚撋系钠骄却龝r(shí)間，用以選擇車輛通過市區(qū)的道路，并表明，道路使用者采用合作學(xué)習(xí)的方法可避免交通瓶頸。

本文安排如下：第2部分?jǐn)⑹鋈绾谓⒔煌Ｐ停A(yù)測交通情況和控制交通。第3部分是就相關(guān)問題得出結(jié)論。第4部分說明了現(xiàn)在正在進(jìn)一步研究的事實(shí)，并介紹了我們的新思想。

The times is a automation times nowadays,traffic light waits for much the industey equipment to go hand in hand with the computer under the control of.Therefore,a good traffic light controls system,will give road aspect such as being crowded,controlling against rules to give a technical improvement.With the fact that the large-scale integrated circuit and the computer art promptness develop,as well as artificial intelligence broad in the field of control technique applies,intelligence equipment has had very big development,the main current being that modern science and technology develops direction.The main body of a book is designed having introduccd a intelligence traffic light systematically.The function being intelligence traffic light navar’s turn to be able to come true has：The crossing carries out supervisory control on four main traffic of some downtown area;Every crossing has the fixed duty period,charges centrefor being able to change it’s period and in depending on a road when being crowded;The motro vehicle breaking rules and regulations to the crossing is able to take a photo immediately,abstracts and the vehicle shop sign.Within world range ,one uses the microelectronics technology,the computer and the technology communicating by letter are a guide’s,centering on IT and IT industry information revolution is in the ascendant.But,how,computer art applies more effective union and there is an effect’s brought it’s effect into play with reality is the most popular topic of scientific community,is also that computer applications is hit by the unparalleled active field nowadays.The main body of a book is applied up mainly from slicing machine’s only realizing intellectualized administration of crossroads traffic light,use operation in controlling the vehicular traffic regularity.Transportation research has the goal to optimize transportation flow of people and goods.As the number of road users constantly increases, and resources provided by current infras-tructures are limited, intelligent control of traffic will become a very important issue in thefuture.However, some limitations to the usage of intelligent tra?c control exist.Avoidingtraffic jams for example is thought to be beneficial to both environment and economy, butimproved traffic-flow may also lead to an increase in demand [Levinson, 2003].There are several models for traffic simulation.In our research we focus on microscopicmodels that model the behavior of individual vehicles, and thereby can simulate dynam-ics of groups of vehicles.Research has shown that such models yield realistic behavior[Nagel and Schreckenberg, 1992, Wahle and Schreckenberg, 2001].Cars in urban traffic can experience long travel times due to inefficient traffic light con-trol.Optimal control of traffic lights using sophisticated sensors and intelligent optimizationalgorithms might therefore bevery beneficial.Optimization of traffic light switching increasesroad capacity and traffic flow, and can prevent tra?c congestions.Traffic light control is acomplex optimization problem and several intelligent algorithms, such as fuzzy logic, evo-lutionary algorithms, and reinforcement learning(RL)have already been used in attemptsto solve it.In this paper we describe a model-based, multi-agent reinforcement learningalgorithm for controlling traffic lights.In our approach, reinforcement learning [Sutton and Barto, 1998, Kaelbling et al., 1996]with road-user-based value functions [Wiering, 2000] is used to determine optimal decisionsfor each traffic light.The decision is based on a cumulative vote of all road users standingfor a traffic junction, where each car votes using its estimated advantage(or gain)of settingits light to green.The gain-value is the difference between the total time it expects to waitduring the rest of its trip if the light for which it is currently standing is red, and if it is green.The waiting time until cars arrive at their destination is estimated by monitoring cars flowingthrough the infrastructure and using reinforcement learning(RL)algorithms.We compare the performance of our model-based RL method to that of other controllersusing the Green Light District simulator(GLD).GLD is a traffic simulator that allows usto design arbitrary infrastructures and traffic patterns, monitor traffic flow statistics such asaverage waiting times, and test different traffic light controllers.The experimental resultsshow that in crowded traffic, the RL controllers outperform all other tested non-adaptivecontrollers.We also test the use of the learned average waiting times for choosing routes of cars through the city(co-learning), and show that by using co-learning road users can avoidbottlenecks.

第三篇：外文翻譯

設(shè)計(jì)一個(gè)位于十字路口的智能交通燈控制系統(tǒng)

摘要：本文模型使用模糊本體的交通燈控制域，并把它應(yīng)用到控制孤立十字路口。本文最重要的目的之一是提出一個(gè)獨(dú)立的可重復(fù)使用的交通燈控制模塊。通過這種方式，增加軟件的獨(dú)立性和為其他的軟件開發(fā)活動(dòng)如測試和維護(hù)，提供了便利。專家對本體論進(jìn)行手動(dòng)的開發(fā)和評估。此外，交通數(shù)據(jù)提取和分類路口使用的人工神經(jīng)網(wǎng)絡(luò)的圖像處理算法。根據(jù)預(yù)定義的XML架構(gòu)，這種信息轉(zhuǎn)化為XML實(shí)例映射到適合使用模糊推理引擎的模糊規(guī)則的模糊本體。把本系統(tǒng)的性能與其他類似的系統(tǒng)性能進(jìn)行比較。比較結(jié)果顯示：在所有的交通條件下，在每個(gè)周期中，對每輛車它有低得多的平均延遲時(shí)間與其他的控制系統(tǒng)相比。

關(guān)鍵詞:模糊本體,智能代理,智能交通系統(tǒng)(ITS),交通信號燈控制(TLC),孤立的十字路口,圖像處理,人工神經(jīng)網(wǎng)絡(luò)

1.引言

作為城市交通增加的結(jié)果,道路網(wǎng)絡(luò)的能力有限和發(fā)展交通工具和方法的技術(shù)方面，許多實(shí)體，關(guān)系，情況和規(guī)則已經(jīng)進(jìn)入交通燈控制域和轉(zhuǎn)化成為一個(gè)知識(shí)領(lǐng)域。這個(gè)領(lǐng)域的建模知識(shí)幫助交通代理和應(yīng)用有效地管理關(guān)于實(shí)時(shí)條件下的交通。全面知識(shí)建模領(lǐng)域的一個(gè)最合適的方法是使用本體概念?！氨倔w論是一個(gè)正式的、明確的一個(gè)共享的概念化的規(guī)范。以前的模型是基本的本體建設(shè)的基礎(chǔ)，為下列建立一個(gè)共享的語義豐富的知識(shí)域。除了本體作為概念化的形式主義的重要性，它有可能超過所代表的數(shù)據(jù)。這種能力將提高有關(guān)性能的決定和其他非智能系統(tǒng)的功能特點(diǎn)。在近年來，本體論上的研究正成為一個(gè)新的熱點(diǎn)話題在不同的活動(dòng)，如人工智能，知識(shí)管理，語義網(wǎng)絡(luò)，電子商務(wù)和幾個(gè)其他應(yīng)用領(lǐng)域。這些領(lǐng)域之一是智能交通系統(tǒng)。一些努力已制成這個(gè)通過展示和使用本體檢測交通領(lǐng)域擁塞，管理非城市道路氣象事件，駕駛阿德?！骼锵到y(tǒng)，共享和整合一個(gè)智能交通系統(tǒng)。本文的目的是介紹一個(gè)紅綠燈有效控制孤立交叉口這方面的知識(shí)重用的控制本體。這種新的辦法適用于智能代理使用知識(shí)決策模糊。該系統(tǒng)采用的圖像來自安裝了監(jiān)控?cái)z像機(jī)拍攝的路口。這些圖像處理利用圖像處理算法和神經(jīng)網(wǎng)絡(luò)的方法，然后發(fā)送到一個(gè)智能代理。第2節(jié)中，我們將簡要地解釋了在這項(xiàng)工作中運(yùn)用的技術(shù)包括seman-TIC網(wǎng)絡(luò)技術(shù)，智能代理技術(shù)和交通的回地面光控制方法。在第3節(jié)，新的系統(tǒng)架構(gòu)是基于分層語義網(wǎng)絡(luò)架構(gòu)。第4節(jié)介紹交通燈控制的模糊本體的建設(shè)。第五節(jié)從路口提取的圖像信息解釋。在第6節(jié)，智能系統(tǒng)的運(yùn)作被完整描述，最后在第7節(jié)對所提出的方法進(jìn)行評估，對結(jié)論進(jìn)行闡述。

2.背景

本節(jié)說明在這項(xiàng)工作中的應(yīng)用技術(shù)包括語義網(wǎng)絡(luò)技術(shù)，特別本體和模糊本體。此外，國家的交通燈控制的藝術(shù)方法是簡要介紹。2.1.語義網(wǎng)絡(luò)技術(shù)

語義網(wǎng)絡(luò)被定義為當(dāng)前Wed的延伸，這些網(wǎng)站的信息都給出明確的含義;使電腦與人更好的合作。有幾層語義Web的建議源自伯納斯滯后階段。在此類別中的所有規(guī)則如表1所示。圖.4顯示輸出模式的示意圖。本次評選有助于智能系統(tǒng)，以確定下一步的階段測序。

另一種模糊的規(guī)則類別涉及估計(jì)優(yōu)化周期時(shí)間。這些規(guī)則的模糊變量是天氣條件，時(shí)間，每天平均車輛擁堵情況。出于這個(gè)原因，60個(gè)模糊規(guī)則被定義了。從氣象研究所取得氣象條件。日期和時(shí)間也是在交通專家的知識(shí)的基礎(chǔ)上以模糊變量形式預(yù)先定義的。圖5顯示日期，時(shí)間和周期時(shí)間的隸屬函數(shù)。當(dāng)天的參數(shù)是在日歷基礎(chǔ)上基于假期和正常的一天與周期時(shí)間量的關(guān)系預(yù)定義的。例如，假期期間的周期時(shí)間是較平日少。因此，平日的隸屬度比假期多。

例如一個(gè)階段選型的模糊規(guī)則如下所述：“如果一個(gè)路口的類型是四的方式，平均車輛擁堵低，平均行人擁堵是中等，然后相類型是簡單的兩階段”。此外，為周期時(shí)間估計(jì)的模糊規(guī)則表示如下：“如果天氣條件是晴天，時(shí)間是早晨，天是正常的，平均車輛擁堵是低，則周期時(shí)間短”。在此類別中的所有規(guī)則都列在附錄A。

在此步驟結(jié)束時(shí)，應(yīng)該對交通燈邏輯控制的項(xiàng)目的有效性進(jìn)行評估。此功能是使用專家的意見。評價(jià)過程的主要目的是顯示發(fā)展的本體和其相關(guān)的軟件環(huán)境的用處。雖然所有的信息，尤其是交通燈控制規(guī)則已提取國際標(biāo)準(zhǔn)和科學(xué)交通文學(xué)，專家的知識(shí)優(yōu)勢是他們最后的正確性驗(yàn)證標(biāo)準(zhǔn)。所有模糊規(guī)則，包括優(yōu)化周期時(shí)間和相位類型的規(guī)則，在這個(gè)過程中，準(zhǔn)備以調(diào)查問卷形式和展現(xiàn)給一些專家包括從德黑蘭警察局交通上校和兩名來自德黑蘭的交通組織工程師。由于德爾菲專家的意見，約有84％的淘汰型規(guī)則和優(yōu)化周期時(shí)間的87％被接受。此外，所有交通邏輯控制的元素包括概念，關(guān)系，屬性和公理都被這些專家進(jìn)行了評估和驗(yàn)證。我們評估邏輯交通控制是基于理論知識(shí)的。在這個(gè)過程中進(jìn)行了兩項(xiàng)活動(dòng)，包括檢查的要求和能力的問題，并在目標(biāo)應(yīng)用環(huán)境測試本體。由于邏輯交通控制已建成的基礎(chǔ)上，如指定要求優(yōu)化循環(huán)時(shí)間，逐步淘汰型，交通的移動(dòng)和優(yōu)化綠燈時(shí)間，每個(gè)階段的序列中，第一項(xiàng)活動(dòng)是最好的結(jié)果。邏輯交通控制滿足所有的交通燈控制的需求，并能回答的能力問題。績效評估機(jī)制，可以支持這種說法。在部分實(shí)驗(yàn)結(jié)果我們驗(yàn)證了這一過程。

第四篇：外文翻譯

中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

超聲測距系統(tǒng)設(shè)計(jì)

原文出處：傳感器文摘 布拉福德：1993年第13頁

摘要：超聲測距系統(tǒng)技校在工業(yè)場車輛導(dǎo)航水聲工程等領(lǐng)域都具有了廣泛的應(yīng)用價(jià)值，目前已應(yīng)用于物理測量，機(jī)器人自動(dòng)導(dǎo)航以及空氣中與水下的目標(biāo)探測、識(shí)別定位等場合，因此，深入研究超聲的探測理論和方法具有重要的實(shí)踐意義，為了進(jìn)一步提高測量的精確度，滿足工程人員對測量精度測距量程和測距儀使用的要求，本文研制了一套基于單片機(jī)的使拱式超聲測距系統(tǒng)。關(guān)鍵詞：超聲波 測距儀 單片機(jī)

1、前言

隨著科技的發(fā)展，人們生活水平的提高，城市發(fā)展建設(shè)加快，城市給排水系統(tǒng)也有較大發(fā)展，其狀況不斷改善，但是，由于歷史原因合成時(shí)間性的許多不可預(yù)見因素，城市給排水系統(tǒng)，特別是排水系統(tǒng)往往落后于城市建設(shè)，因此，經(jīng)常出現(xiàn)開挖已經(jīng)建設(shè)好的建筑設(shè)施來改造排水系統(tǒng)的現(xiàn)象。城市污水給人們帶來的困擾，因此箱的排污疏通對大城市給排水系統(tǒng)污水理，人們生活舒適顯得非常重要。而設(shè)計(jì)研制箱涵排水疏通移動(dòng)機(jī)器人的自動(dòng)控制系統(tǒng)，保證機(jī)器人在箱涵中自由排污疏通，是箱涵排水系統(tǒng)疏通機(jī)器人的設(shè)計(jì)研制的核心部分，控制系統(tǒng)核心部分就是超聲波測儀的研制。因此，設(shè)計(jì)好的超聲波測距儀就顯得非常重要了。

1.1課題背景

隨著經(jīng)濟(jì)的發(fā)展與汽車科學(xué)技術(shù)的進(jìn)步，公路交通呈現(xiàn)出行駛高速化、車流密集化和駕駛員非職業(yè)化的趨勢。同時(shí)，隨著汽車工業(yè)的飛速發(fā)展，汽車的產(chǎn)量和保有量都在急劇增加。但公路發(fā)展、交通管理卻相對落后，導(dǎo)致了交通事故與日劇增，城市里尤其突出。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，已得到各國政府的廣泛關(guān)注。中國政府也高度重視智能交通系統(tǒng)的研究開發(fā)與推廣應(yīng)用。汽車防撞系統(tǒng)作為ITS 發(fā)展的一個(gè)基礎(chǔ)，它的成功與否對整個(gè)系統(tǒng)有著很大的作用。從傳統(tǒng)上說，汽車的安全可以分為兩個(gè)主要研究方向:一是主動(dòng)式安全技術(shù)，即防止事故的發(fā)生，該種方式是目前汽車安全研究的最終目的;二是被動(dòng)式安全技術(shù)，即事故發(fā)生后的乘員保護(hù)。目前汽車安全領(lǐng)域被動(dòng)安全研究較多，主要從安全氣囊、ABS(防抱死系統(tǒng))和懸架等方面著手，以保證駕乘人員的安全。從經(jīng)濟(jì)性和安全性兩方面來說，中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

這些被動(dòng)安全措施是在事故發(fā)生時(shí)刻對車輛和人員進(jìn)行保護(hù)，有很大的局限性，因而車輛的主動(dòng)安全研究尤為重要，引出了本文研究的基于單片機(jī)的超聲波測距系統(tǒng)。這個(gè)系統(tǒng)是一種可向司機(jī)預(yù)先發(fā)出視聽語音信號的探測裝置。它安裝在汽車上，能探測企圖接近車身的行人、車輛或周圍障礙物;能向司機(jī)及乘員提前發(fā)出即將發(fā)生撞車危險(xiǎn)的信號，促使司機(jī)采取應(yīng)急措施來應(yīng)付特殊險(xiǎn)情，避免損失。

1.2 課題設(shè)計(jì)的意義

隨著現(xiàn)代社會(huì)工業(yè)化程的發(fā)展，汽車這一交通工具正為越來越多的人所用，但是隨之而來的問題也顯而易見，那就是隨著車輛的增多，交通事故的頻繁發(fā)生，由此導(dǎo)致的人員傷亡和財(cái)產(chǎn)損失數(shù)目驚人。對于公路交通事故的分析表明，80%以上的車禍?zhǔn)掠捎隈{駛員反應(yīng)不及所引起的，超過65%的車輛相撞屬于追尾相撞，其余則屬于側(cè)面相撞。奔馳汽車公司對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。因此，大力研究開發(fā)如汽車防撞裝置等主動(dòng)式汽車輔助安全裝置，減少駕駛員的負(fù)擔(dān)和判斷錯(cuò)誤，對于提高交通安全將起到重要的作用。顯然，此類產(chǎn)品的研究開發(fā)具有極大的實(shí)現(xiàn)意義和廣闊的應(yīng)用前景。

1.3超聲波測距在汽車上應(yīng)用的介紹

超聲波倒車測距儀(俗稱電子眼)是汽車倒車防撞安全輔助裝置，能以聲音或者更為直觀的數(shù)字形式動(dòng)態(tài)顯示周圍障礙物的情況。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。后繼的產(chǎn)品可以顯示車后障礙物離車體的距離。其大多數(shù)產(chǎn)品探測范圍在0.4～1.5m，有的產(chǎn)品能達(dá)到0.35～2.5m，并有距離顯示、聲響報(bào)警、區(qū)域警示和方位指示，有些產(chǎn)品還具備開機(jī)自檢功能。目前市場上還出現(xiàn)了具有語音報(bào)警功能的產(chǎn)品。這些產(chǎn)品存在的主要問題是測量盲區(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。汽車防撞雷達(dá)之所以能實(shí)現(xiàn)防撞報(bào)警功能，主要有超聲波這把無形尺子, 它測量最近障礙物的距離, 并告訴給車主。其實(shí)超聲測距原理簡單: 它發(fā)射超聲波并接收反射回波, 通過單片機(jī)計(jì)數(shù)器獲得兩者時(shí)間差t, 利用公式S=Ct/2計(jì)算距離, 其中S為汽車與障礙物之間的距離, C為聲波在介質(zhì)中的傳播速度。

本文介紹的超聲測距系統(tǒng)共有2只超聲波換能器(俗稱探頭),分別布置在汽車的后左、后右2個(gè)位置上。能檢測前進(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。系統(tǒng)采用一片STC89C52單片機(jī)對兩路超聲波信號進(jìn)行循環(huán)采集。超聲波是指頻率高于20HHZ的機(jī)械波。為了以超聲波作為檢測手段，必須產(chǎn)生超生波和接收超聲波。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。超聲波傳感器有發(fā)送器和接收器，但一個(gè)超聲波傳感器也可具有發(fā)送和接收聲波的雙重作用。超聲波傳感器是利用壓電效應(yīng)的原理將電能和超聲波相互轉(zhuǎn)化，即在發(fā)射超聲波的時(shí)候，將電能轉(zhuǎn)換，發(fā)射超聲波；而在收到回波的時(shí)候，則將超聲振動(dòng)轉(zhuǎn)換成電信號。超聲波測距的原理一般采用渡越時(shí)間法。首先測出超聲波從發(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。測量距離的方法有很多種，短距離的可以用尺，遠(yuǎn)距離的有激光測距等，超聲波測距適用于高精度的中長距離測量。因?yàn)槌暡ㄔ跇?biāo)準(zhǔn)空氣中的傳播速度為331.45米/秒，由單片機(jī)負(fù)責(zé)計(jì)時(shí)，單片機(jī)使用12.0M晶振，所以此系統(tǒng)的測量精度理論上可以達(dá)到毫米級。由于超聲波指向性強(qiáng)，能量消耗緩慢，在介質(zhì)中傳播距離遠(yuǎn)，因而超聲波可以用于距離的測量。利用超聲波檢測距離，設(shè)計(jì)比較方便，計(jì)算處理也較簡單，并且在測量精度方面也能達(dá)到要求。超聲波發(fā)生器可以分為兩類：一類是用電氣方式產(chǎn)生超聲波，一類是用機(jī)械方式產(chǎn)生超聲波。本設(shè)計(jì)屬于近距離測量，可以采用常用的壓電式超聲波換能器來實(shí)現(xiàn)觸發(fā)單元。

利用超聲波測距的工作，就可以根據(jù)測量發(fā)射波與反射波之間的時(shí)間間隔，從而達(dá)到測量距離的作用。其主要有三種測距方法：

（1）相位檢測法，相位檢測法雖然精度高，但檢測范圍有限；

（2）聲波幅值檢測法，聲波幅值檢測法易受反射波的影響；

（3）渡越時(shí)間檢測法，渡越時(shí)間檢測法的工作方式簡單，直觀，在硬件控制和軟件設(shè)計(jì)上都非常容易實(shí)現(xiàn)。其原理為：檢測從發(fā)射傳感器發(fā)射超聲波，經(jīng)氣體介質(zhì)傳播到接收傳感器的時(shí)間，這個(gè)時(shí)間就是渡越時(shí)間。本設(shè)計(jì)的超聲波測距就是使用了渡越時(shí)間檢測法。在移動(dòng)車輛中應(yīng)用的超聲波傳感器，是利用超聲波在空氣中的定向傳播和固體反射特性（縱波），通過接收自身發(fā)射的超聲波反射信號，根據(jù)超聲波發(fā)出及回波接收的時(shí)間差和傳播速度，計(jì)算傳播距離，從而得到障礙物到車輛的距離。

中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文 超聲波測距原理

2.1 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。超聲波發(fā)生器內(nèi)部結(jié)構(gòu)，它有兩個(gè)壓電晶片和一個(gè)共振板。當(dāng)它的兩極外加脈沖信號，其頻率等于壓電晶片的固有振蕩頻率時(shí)，壓電晶片將會(huì)發(fā)生共振，并帶動(dòng)共振板振動(dòng)，便產(chǎn)生超聲波。反之，如果兩極板間未加電壓，當(dāng)共振板接收到超聲波時(shí)，將壓迫壓電晶片做振動(dòng)，將機(jī)械能轉(zhuǎn)換為電信號，這是它就成為超聲波接收器了。

測量脈沖到達(dá)時(shí)間的傳統(tǒng)方法是以擁有固定參數(shù)的接收信號開端為基礎(chǔ)的。這個(gè)信號恰恰選于噪音水平之上，然而脈沖到達(dá)時(shí)間被定義為脈沖信號剛好超過界限的第一時(shí)刻。一個(gè)物體的脈沖強(qiáng)度很大程度上取決于這個(gè)物體的自然屬性尺寸還有它與傳感器的距離。進(jìn)一步說，從脈沖起始點(diǎn)到剛好超過界限之間的時(shí)間段隨著脈沖的強(qiáng)度而改變。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)。強(qiáng)度較強(qiáng)的脈沖會(huì)比強(qiáng)度較弱的脈沖超過界限的時(shí)間早點(diǎn)，因此我們會(huì)認(rèn)為強(qiáng)度較強(qiáng)的脈沖屬于較近的物體。

2.2 超聲波測距原理

超聲波發(fā)射器向某一方向發(fā)射超聲波，在發(fā)射時(shí)刻的同時(shí)開始計(jì)時(shí)，超聲波在空氣中傳播，途中碰到障礙物就立即返回來，超聲波接收器收到反射波就立即停止計(jì)時(shí)。超聲波在空氣中的傳播速度為340m/s，根據(jù)計(jì)時(shí)器記錄的時(shí)間t，就可以計(jì)算出發(fā)射點(diǎn)距離障礙物的距離(s)，即：s=340t/2

中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

3、超聲波測距系統(tǒng)的電路設(shè)計(jì)

系統(tǒng)的特點(diǎn)是利用單片機(jī)控制超聲波的發(fā)射和超聲波自發(fā)射至接受往返時(shí)間的計(jì)時(shí)，單片機(jī)選用C51，經(jīng)濟(jì)易用，且片內(nèi)有4K的ROM，便于編程。電路的原理如圖1所示。

圖1 電路原理圖

中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

3.1 40kHz脈沖的產(chǎn)生與超聲波發(fā)射

測距系統(tǒng)中的超聲波傳感器采用UCM40的壓電陶瓷，它的工作電壓是40kHz的脈沖信號，這由單片機(jī)執(zhí)行下面的程序來產(chǎn)生。puzel：mov 14h，#12h

here： cp1.0；

nop；

nop；

nop；

djnz 14h，here；

Ret

前方測距電路的輸出端接單片機(jī)P1.0端口，單片機(jī)執(zhí)行上面的程序后，在P1.0端口輸出一個(gè)40khz的脈沖信號，經(jīng)過三極管T放大，驅(qū)動(dòng)超聲波發(fā)射頭UCM40T，發(fā)出40khz的脈沖超聲波，且持續(xù)發(fā)射200ms。右側(cè)合作側(cè)測距電路的輸入端分別接P1.1和P1.2端口，工作原理和前方測距電路相同。

超聲波發(fā)射持續(xù)200ms 輸出40kHz方波

3.2 超聲波的接收與處理

接收頭采用與發(fā)射頭配對的UCM40R，將超聲波調(diào)制脈沖變?yōu)殡妷盒盘?，?jīng)運(yùn)算放大器ic1a和ic1b兩級放大后加至IC2,。IC2是帶有鎖定環(huán)的音頻譯碼集成塊LM567，內(nèi)部壓控振蕩器的中心頻率f0=1/1.1R8C3，電容C4決定其帶寬。調(diào)節(jié)R8在發(fā)射的載頻上，則LM567輸入信號大于25mv，輸出端8腳由5由高電平躍變?yōu)榈碗娖?，作為中斷請求信號，送至單片機(jī)處理。

前方測距電路的輸出端接至單片機(jī)INT0端口，中斷優(yōu)先級最高，左、右測距電路的輸出通過與門IC3A的輸出接單片機(jī)的INT1端口，同時(shí)單片機(jī)P1.3和P1.4接到IC3A的輸入端，中斷源的識(shí)別由程序查詢來處理，中斷優(yōu)先級為先右后左。部分源程序如下： receive1：push psw

push acc

clr ex1；關(guān)中斷源1

jnb p1.1，right;P1.1引腳為0，轉(zhuǎn)至右側(cè)距電路中斷服務(wù)程序

jnb p1.2,left;P1.2 引腳為0，轉(zhuǎn)至左測距中斷電路服務(wù)程序 returne：SETB EX1；

開外部中斷1

pop acc

中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

pop psw

reti right：

...；

右測距電路中斷服務(wù)程序入口

ajmp return

left：

...；

左測距電路中斷服務(wù)程序入口

ajmp return

3.3 計(jì)算超聲波傳播時(shí)間

在啟動(dòng)發(fā)射電路的同時(shí)啟動(dòng)單片機(jī)內(nèi)部的定時(shí)器T0，利用定時(shí)器的計(jì)數(shù)功能，記錄超聲波發(fā)射的時(shí)間和受到反射波的時(shí)間。當(dāng)收到超聲波反射波時(shí)，接受電路輸出端產(chǎn)生一個(gè)負(fù)跳變，在INT0或INT1端產(chǎn)生一個(gè)中斷請求信號，單片機(jī)響應(yīng)外部中斷請求，執(zhí)行外部中斷服務(wù)子程序，讀取時(shí)間差，計(jì)算距離。其部分源程序如下：

RECEIVEO: PUSH PSW

PUSH ACC CLR EX0;

關(guān)外部中斷0 讀取時(shí)間值

MOV R7,TH0;MOV R6,TL0 CLR C MOV A,R6 SUBB A,#0BBH;MOV 31H,A;MOV A,R7 SUBB A,#3CH MOV 30H,A SETB EX0;POP ACC

POP PSW

RETI 對于一個(gè)平坦的目標(biāo)，測量距離包括兩個(gè)階段：粗糙的測量和精細(xì)的測量。第一步：脈沖的傳送產(chǎn)生一種簡單的超聲波

第二步：根據(jù)公式改變回波放大器的獲得量直到回?fù)鼙粰z測到。第三步：檢測兩種回波的振幅與過零時(shí)間。

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。通過脈沖的周期設(shè)置下一個(gè)脈沖。根據(jù)第二部的數(shù)據(jù)設(shè)定時(shí)間窗。

第五步：發(fā)射兩竄脈沖產(chǎn)生干擾波。測量過零時(shí)間與回波振幅。如果逆向發(fā)生在回波中，決定要不通過在低氣壓插入振幅。

第六步：通過公式計(jì)算距離y。

中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

4、超聲波測距系統(tǒng)的軟件設(shè)計(jì)

軟件分為倆部分，主程序和中斷服務(wù)程序。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。定時(shí)中斷服務(wù)子程序完成三方向超聲波的輪流發(fā)射，外部中斷服務(wù)子程序主要完成時(shí)間值的讀取、距離計(jì)算、結(jié)果的輸出等工作。

中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

5、結(jié)論

對所要求測量范圍30cm-200cm內(nèi)的平面物體做了多次測量發(fā)現(xiàn)，其最大誤差為1.5cm，且重復(fù)性好。可見基于單片機(jī)設(shè)計(jì)的超聲波測距系統(tǒng)具有硬件結(jié)構(gòu)簡單、工作可靠、測量誤差小等特點(diǎn)。因此，它不僅可用于移動(dòng)機(jī)器人，還可以用在其他檢測系統(tǒng)中。

思考：至于為什么不用接收管做放大電路，因?yàn)榉糯蟊稊?shù)搞不好，集成放大電路，還帶自動(dòng)電平增益控制，放大倍數(shù)為76db，中心頻率是38k到40k，剛好是超聲波傳感器的諧振頻率。

中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

參考文獻(xiàn)

1.Fox，J.D.，Khuri-Yakub，B.T.and Kino，G.S.，“High Frequency Acoustic Wave Measurement in Air”，in Proceedings of IEEE 1983 Ultrasonic Symposium，October 31-2 November，1983，Atlanta，GA，pp.581-4.2.Martin Abreu，J.M.，Ceres,R.And Freire,T.,“Ultrasonic Ranging: Envelope Analysis Gives Improved Accuracy”,Sensor Review, Vol.12 No.1,1992,pp.17-21.3.Parrilla， M., Anaya,J.J and Fritsch C.,‖Digital Signal Processing Techniques for High Accuracy Ultrasonic Range Measurement:,IEEE Transactions: Instrumentation and Measurement.Vol.40 No.4, August 1991,pp.750-63.4.Canali, C., Cicco, G.D., 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, IE-29 No.4,1982, pp.336-41.5.Martin, J.M., Ceres, R., Calderon, L and Freire, T., ‖Ultrasonic Ranging Gets Themal Correction‖, Sensor Review, Vol, 9 No.3, 1989,pp.153-5.中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

Ultrasonic ranging system design Publication title: Sensor Review.Bradford:1993.Vol.13 ABSTRACT: Ultrasonic ranging technology has wide using worth in many field, such as the industrial locale, vehicle navigation and sonar engineering.Now it has been used in level measurement, self-guided autonomous vehicles, fieldwork robots automotive navigation, air and underwater target detection, identification ,location and so on.So there is an important practicing meaning to learn the ranging theory and ways deeply.To 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 developed.Keywords: Ultrasound r, Ranging System, Single Chip Processor

1.Introductive With the development of science and technology, the improvement of people’s standard of living, speeding up the development and construction of the city.Urban drainage system have greatly developed their situation is constantly improving.However, due to historical reasons many unpredictable factors in the synthesis of her time, the city drainage system.In particular drainage system often lags behind urban construction.Therefore, there are often good building excavation has been building facilities to upgrade the drainage system phenomenon.It brought to the city sewage, and it is clear to the city sewage and drainage culvert in the sewage treatment system.Confort is very important to people’s lives.Mobile robots designed to clear the drainage culvert and the automatic control system Free sewage culvert clear guarantee robot, the robot is designed to clear the culvert sewage to the core.Control System is the core component of the development of ultrasonic range finder.Therefore, it is very important to design a good ultrasonic range finder.1.1 subject background

With the development of economy and car scientific and technological progress, highway traffic presents driving fast pace, traffic dense is changed and the driver not professional trend.At the same time, along with the rapid development of auto industry, automobile yield and quantities are increased dramatically.But road development，中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

transportation management is relatively backward, leading to a large number of traffic accidents in some cities, especially prominent.Intelligent transportation system in the world, ITS transportation science and technology of advanced technology, ITS exerting existing infrastructure of potential, enhance the transport efficiency, safeguard traffic safety and ease traffic wager plug, improving urban environment aspects of outstanding performance, has received the governments of widespread concern.The Chinese government is also highly intelligent transportation system of the development and popularization applications.The automotive anti-collision system as ITS development of a base, ITS success to the whole system has a very significant role.Traditionally, auto safety said can be divided into two main research direction: first,it is active safety technology, including the prevention of accidents, the way is now automotive safety research ultimate purpose;second, it is passive safety technique, namely the occupant protection after the accident.Now automotive safety field passive safety more research, mainly from the airbag, ABS(antilock brakes)and suspension from the aspects such as to ensure safety of personnel rides.From the economic and safety two ways, these passive safety measures is the accident of vehicle and personnel moments protection, with great limitations, thus vehicle active safety research is particularly important, leads to a of this study is based on single chip ultrasonic ranging system.This system is a kind of can advance to the driver issued audio-visual speech signal detection devices.It is installed in cars that can detect trying to approach the body of a car pedestrians and vehicles or around obstacles, Can send to the driver and crew imminent danger ahead of the signal, prompting a crash drivers take emergency measures to cope with special danger, avoid the loss.1.2 question design significance

Along with the development of modern society industrialization process, car this traffic tools are used for more and more people, but any problem has obvious that along with the increase in vehicles, traffic accident, which led to the frequent occurrence of casualties and property losses number astonishing.For highway traffic accident analysis showed that more than 80% of the accident due to the driver reaction inferior things, caused more than 65% of vehicle collision, the rest belongs to tracing cauda collided belongs to the side collision.Mercedes-benz Automobile Company for all kinds of traffic accident research shows that: if the driver can early 1S are aware

中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

that a accident risk and take the appropriate corrective measures, the overwhelming majority of traffic accidents can be avoided.Therefore, vigorously research and development as the automotive anti-collision device etc active car auxiliary safe device, reduce the burden and misjudgments drivers to improve the traffic safety will play an important role.Obviously, this kind of product research and development has great realize meaning and broad application prospects.1.3 Ultrasonic ranging in automotive applications introduced

Ultrasonic back-draft rangefinder(known as electron optics)automotive anti-collision reversing device, can safe adjunct to sound or more intuitive digital form the dynamic display of around obstacles.Its earlier products is to use buzzer alarm, hum more anxious, and says vehicles from obstructions closer.Subsequent product can display the car from the body after the obstacles distance.Most of its products detection range in 0.4 ~ 1.5 m, some product can achieve 0.35 ~ 2.5 m, and have distance display, sound alarm, area-warning and azimuth instructions, some products also has the boot self-checking function.Still appeared on the market at present with voice alarm function of products.These products are the main problem is big, alarm measuring blind area lags behind, without considering the automobile braking inertial factors and make drivers brake lag, the anti-interference ability is not strong, misstatement or more.The automotive anti-collision radar is able to realize impact-proof alarm functions, basically have ultrasonic this intangible ruler, it recently obstacles distance measurement, and told to the owner.Actually ultrasonic range-finding principle simple: it emit ultrasonic echo, and receive reflected by microcontroller counter obtain both lag using formula S = t, Ct / 2 calculating distances, including S for cars and obstacles, C for the distance between the sound wave propagation in the medium speed.This paper introduces the ultrasonic ranging system only have 2 ultrasonic transducer(known as probe)respectively, decorate in cars left and right after after 2 position.Capable of detecting forward and reverse direction obstacle distance, the rearview mirror built-in display element display distance and direction, issued must be sound, plays the role of hints and alert.System USES a STC89C52 SCM two way ultrasonic signal cyclicly acquisition.Ultrasonic refers to the 20HHZ wave frequency is over.In order to use the ultrasonic detection means, must generate as ultrasonic wave and receiving damnation.Complete the functions of the device is called the

中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

ultrasonic sensor, habit, ultrasonic transducer or ultrasonic probe.Ultrasonic sensors have both transmitters and receivers, but a ultrasonic sensors can also has the sending and receiving the sound waves of the dual role.Ultrasonic sensors is using the principle of piezoelectric effect and ultrasonic energy conversion, be in namely emit ultrasonic, energy conversion, launch ultrasonic, And in the stockades, received echo ultrasonic vibration into electrical signal.Ultrasonic ranging principle generally USES the time method for the crossing.First measured ultrasonic from the launch to meet obstacles returns experience of time, again multiply ultrasonic speed of get twice the distance between the sound source and obstacles.Measuring distance a variety of ways, short can use ruler, long-range laser displacement etc, are suitable for high accuracy of ultrasonic ranging in long distance measurement.Because of ultrasound in standard air of propagation speed 331.45 meters per second, by single-chip microcomputer is responsible for timing, SCM use 12.0 M crystals, so the system of measurement precision theory can achieve mm level.Because of ultrasonic directivity strong, energy consumption is slow, in a medium transmission distance, thus ultrasonic can be used for distance measurement.Using ultrasonic detection distance, the design is more convenient, computing procese also relatively simple, and the measurement precision can also meet the requirements.Ultrasonic generator can be divided into two kinds: one kind is to use electrical means producing ultrasonic, one kind is with mechanical approach to producing ultrasonic.This design belongs to nearly distance measurement, can use commonly used the piezoelectric ultrasonic transducer to achieve trigger unit.Using ultrasonic ranging work, can according to measuring launch reflection wave wave and the time interval between the measured distance, so as to achieve the effect.It mainly have three ranging methods:

(1)phase assay, phase assays high precision, but detection though limited range，(2)sound amplitude assay, acoustic amplitude assay vulnerable reflection wave influence;

(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 implement.Its principle is: from the launch emit ultrasonic detection sensor, the gas medium spread to receive sensor of time, this time is crossing the more time.This design is the use of ultrasonic ranging the crossing the time assay.In 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(p-wave)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 distance.中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

2.A principle of ultrasonic distance measurement

2.1 the principle of piezoelectric ultrasonic generator

Piezoelectric ultrasonic generator is the use of piezoelectric crystal resonators to work.Ultrasonic generator, the internal structure as shown, it has two piezoelectric chip and a resonance plate.When 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 generated.Conversely, if the two are not inter-electrode voltage, when the board received ultrasonic resonance, it will be for vibration suppression, then it becomes the ultrasonic receiver.The traditional way to determine the moment of the echo’s arrival is based on thresholding the received signal with a fixed reference.The 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 threshold.The intensity of an echo reflecting from an object strongly depends on the object’s nature, size and distance from the sensor.Further, 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 moments.The stronger one will surpass the threshold earlier than the weaker, so it will be considered as belonging to a nearer object.2.2 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 clock.Ultrasonic 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

3.Ultrasonic Ranging System for the Second Circuit Design

System is characterized by single-chip microcomputer to control the use of ultrasonic transmitter and ultrasonic receiver since the launch from time to time, single-chip selection of 8751,economic-to –use, and the chip has 4K of ROM, to facilitate programming.Circuit schematic diagram shown in Figure 1.Figure 1 circuit principle diagram

中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

3.1 40 kHz ultrasonic pulse generated with the launch

Ranging system using the ultrasonic sensor of piezoelectric sensors UCM40, its operating voltage of the pulse signal is 40kHz, which by the single-chip implementation of the following procedures to generate.Puzel:mov 14h,# 12h;ultrasonic firing continued 200ms here:cpl pl.0;output 40 kHz square wave

nop;

nop;nop;djnz 14h, here;ret Ranging in front of single-chip termination circuit P1.0 input port, single chip implementation of the above procedure, the P1.0 port in a 40kHz pulze output signal, after amplification transistor T, the drive to launch the first ultrasonic UCM40T, issued 40kHz ultrasonic pulse, and the continued launch of 200ms.Ranging the right and the left side of the circuit, respectively, then input port P1.1 and P1.2, the working principle and circuit in front of the same location.3.2 Reception and processing of ultrasonic

Used to receive the first launch of the first pair UCM40R, the ultrasonic pulse modulation signal into an alternating voltage, the op-amp amplification IC1A and after polarization IC1B to IC2.IC2 is locked loop with audio decoder chip LM567, internal voltage-controlled oscillator center frequency of f0=1/1.1R8C3, capacitor C4 determine their target bandwidth.R8-conditioning in the launch of the carrier frequency on the LM567 input signal is greater than 25Mv, the output from the high jump 8 feet into a low-level, as interrupt request signals to the single-chip processing.Ranging in front of single-chip termination circuit port INT0 interrupt the highest priority, right or left location of the output circuit with output gete IC3A access INT1 port single-chip, while single-chip P1.3 and P1.4 received input IC3A, interrupted by the process to identify the source code is as follows: receivel:

push psw

push ace

中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

cir ex1: related external interrupt 1

jnb p1.1, right;P1.1 pin to 0, ranging from right to interrupt service rountine circuit

jnb p1.2, left;P1.2 pin to 0, to the left ranging circuit

interrupt service routine return:SETB EX1;open external interrupt 1

pop

acc pop

psw reti right:…;right location entrance circuit interrupt service rountine

Ajmp Return left:…;left Ranging entrance circuit interrupt service rountine

Ajmp Return

3.3 The calculation of ultrasonic propagation time

When you start firing at the same time start the single-chip circuitry within the timer T0, the use of timer counting function records the time and the launch of ultrasonic reflected wave received time when you receive the ultrasonic reflected wave, the receiver circuit outputs a negative jump in the end of INT0 or INT1 interrupt request generates a signal, single-chip microcomputer in response to external interrupt request, the implementation of the external interrupt service subroutine, read the time difference, calculating the distance.Some of its source is as follows: RECEIVE0: PUSH PSW PUSH ACC CLR EX0;related external interrupt 0 MOV R7, TH0;read the time value MOV R6, TL0 CLR C MOV A, R6 SUBB A,#0BBH;calculate the tome difference MOV 31H, A;storage results MOV A, R7 SUBB A,#3CH

中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

MOV 30H,A SETB EX0;open external interrupt 0 POP ACC POP PAW RETI For a flat target, a distance measurement consists of two phases: a coarse measurement and, a fine measurement: Step 1: Transmission of one pulse train to produce a simple ultrasonic

Wave.Step 2: Changing the gain of both echo amplifiers according to equation，until the echo is detected.Step 3:detection of te amplitudes anf zero-crossing times of both echoes.Step 4:setting the gains of both echo amplifiers to normalize the output at, say 3 volts.Setting the period of the next pulses according to the: period of echoes.Setting the time window according to the data of step 2.Step 5:sending two pulse trains to produce an interfered wave.Testing the zero-crossing in the echo,detemine to otherwise calculate to by interpolation using the amplitudes near the trough.Derive t sub ml and t sub m2.Step6: Calculation of the distance y using equation.中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

4.The ultrasonic ranging system software design

Software is divided into two parts, the main program and interrupt service routine.Completion of the work of the main program is initialized, each sequence of ultrasonic transmitting and receiving control.Tnterrupt service routines from time to complete three of the rotation direction of ultrasonic launch, the main external interrupt service subroutine to resd the value of completion time, distance calculation, the results of the output and so on.中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

5.Conclusions

Required measuring range of 30cm~200cm objects inside the plane to do a number of measurements found that the maximum error is 0.5cm, and good reproducibility.Single-chip design can be seen on the ultrasonic ranging system has a hardware structure is simple, reliable, small features such as measurement error.Therefore, it can be used not only for mobile robot can be used in other detection systems.Thoughts: As for why the receiver do not have the transistor amplifier circuit, because the magnification well, integrated amplifier, but also with automatic gain control level, magnification to 76dB, the center frequency is 38k to 40k, is exactly resonant ultrasonic sensors frequency.中原工學(xué)院畢業(yè)設(shè)計(jì)（論文）譯文

REFERENCES 1.Fox,J.D.,Khuri-Yakub, B.T.and Kino, G.S., ‖High Frequency Acoustic Wave Measurement in Air‖, in Proceedings of IEEE 1983 Ultrasonic Symposium, October 31-2 November, 1983, Atlanta, GA, pp.581-4.2.Martin Abreu,J.M.,Ceres,R.and Freire, T.,‖Ultrasonic Ranging: Envelope Analysis Gives Improved Accuracy‖, Sensor Review, Vol.12No.1,1992, pp.17-21.3.Parrilla， M., Anaya,J.J and Fritsch C.,‖Digital Signal Processing Techniques for High Accuracy Ultrasonic Range Measurement:,IEEE Transactions: Instrumentation and Measurement.Vol.40 No.4, August 1991,pp.750-63.4.Canali, C., Cicco, G.D., 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, IE-29 No.4,1982, pp.336-41.5.Martin, J.M., Ceres, R., Calderon, L and Freire, T., ‖Ultrasonic Ranging Gets Themal Correction‖, Sensor Review, Vol, 9 No.3, 1989,pp.153-5.24

第五篇：外文翻譯

Low Voltage Flyback DC-DC Converter For

Power Supply Applications Hangzhou Liu1, John Elmes2, Kejiu Zhang1, Thomas X.Wu1, Issa Batarseh1

Department of Electrical Engineering and Computer Science, University of Central Florida, Orlando, FL 32816, USA Advanced Power Electronics Corporation, Orlando, FL 32826, USA Abstract ：In this paper, we design a low voltage DC-DC converter with a flyback transformer.The converter will be used as a biased power supply to drive IGBTs.The flyback transformer using planar EI-core is designed and simulated using ANSYS PExprt software.Besides, anLT3574 IC chip from Linear Technology has been chosen for converter control.Finally, the converter modeling and simulation are presented and PCB layout is designed.Keywords：Flyback, anLT3574IC, PCB

I.INTRODUCTION The goal of this project is to develop and build a prototype of a high-efficiency, high-temperature isolated DC-DC converter to be used as a biased power supply for driving a complementary IGBT pair.It is important that the converter can deliver the required power at an ambient temperature of up to 100℃;therefore it has to be efficient so that its components do not exceed their maximum temperature ratings.The final converter will be completely sealed and potted in a metal case.The input voltage range for this converter is from 9V to 36V.The output sides have two terminals, one is﹢16V and the other one is﹣6V.In order to get the desired performance, anLT3574 IC chip from Linear Technology is used.The key to this design is the flyback transformer.The transformer using planar EI-core is designed and simulated using ANSYS PExprt software.Finally, the PCB layout of the converter will be presented.II.KEY DESIGN OUTLINE For this flyback topology, the output voltage can be determined by both the transformer turns ratio and the flyback loop resistor pairs.Therefore, at the initial design stage, we can choose a convenient turn’s ratio for the transformer, and modify it later on if necessary to make sure the output performance is desirable and the transformer will not saturate [1].The relationship between transformers turns ratio and duty cycle can be found as

Where n is the transformer turns ratio, D is the duty cycle, VO` is the sum of the output voltage plus the rectifier drop voltage, VIN is the input voltage of the transformer.The value of feedback resistor can be calculated as

Where RREF is the reference resistor, whose value is typically 6.04k?;α is a constant of 0.986;VBG is the internal band gap reference voltage, 1.23V;and VTC is normally 0.55V [1].With a specific IC chosen, the converter circuit can be designed based on a demo circuit and some parameters may need to be modified if necessary to optimize the performance.Furthermore, in LT Spice, a large number of simulations need to be done with different conditions such as load resistor values and input voltage levels.It is important to make sure that the output voltage can be regulated well with all these different conditions.The most critical part of the design is the flyback transformer.With high switching frequency, the AC resistance can only be estimated based on some traditional methods such as Dowell’s curve rule [2].In order to get more accurate values of AC resistance values;we propose to use finite element electromagnetic software ANSYS PExprt to do the design [3].At the initial design stage, key parameters such as the worst-case input voltage, frequency, material, inductance values will be decided.After that, these data will be imported to the software, from which an optimized solution will be generated.III.CONVERTER SIMULATION RESULTS We choose LT3574 chip in this design.From the simulation results in Figure 1 and Table 1, it clearly shows that the output voltages which are﹢16V and-6V respectively can be regulated pretty well with the input voltage range from 9V to 36V.The voltage tolerance ranges are from ﹢15V to ﹢19V and-12V toDC converter for low voltage power supply application has been designed.The modeling and simulation results are presented.Based on the design specifications, a suitable IC from Linear Technology is chosen.A large amount of circuit simulations with different conditions such as load resistor values and input voltage levels are presented to get the desirable output voltage and current performance.The transformer has been designed including electrical, mechanical and thermal properties.With all the specific components decided, the PCB layout of the converter has been designed as well.REFERENCE

[1] Linear Technology Application Notes , Datasheet of Isolated Flyback Converter Without an Opto-Coupler, http://cds.linear.com/docs /Datasheet/3574f.pdf.[2] P.L.Dowell, “Effect of eddy currents in transformer windings” Proceedings of the IEE, NO.8 PP.1387-1394, Aug 1966.[3] S.Xiao, “Planar Magnetics Design for Low-Voltage DC-DC Converters” MS, 2004.[4] ANSYS Application Notes, PEmag Getting Started: A Transformer Design Example, http://004km.cn/download/ EDA/Maxwell9/planarGS0601.pdf.[5] K.Zhang;T.X.Wu;H.Hu;Z.Qian;F.Chen.;K.Rustom;N.Kutkut;J.Shen;I.Batarseh;“Analysis and design of distributed transformers for solar power conversion” 2011 IEEE Applied Power Electronics Conference and Exposition(APEC), v l., no., pp.1692-1697, 6-11 March 2011.[6] Zhang.;T.X.Wu.;N.Kutkut;J.Shen;D.Woodburn;L.Chow;W.Wu;H.Mustain;I.Batarseh;,“Modeling and design optimization of planar power transformer for aerospace applic ation,” Proceedings of the IEEE 2009 National, Aerospace & Electronics Conference(NAECON), vol., no., pp.116-120, 21-23 July 2009.[7] Ferroxcube Application Notes, Design of Planar Power Transformer,