超聲波測距儀外文翻譯

1、<p><b>　　淮 陰 工 學 院</b></p><p>　　畢業(yè)設計(論文)外文資料翻譯</p><p>　　附件1：外文資料翻譯譯文</p><p><b>　　超聲波測距儀</b></p><p>　　摘要：提出了一種超聲波測距儀來抵消的溫度和濕度引起的變化，包括測量單元和參考

2、標準。每一個單元產(chǎn)生重復的一系列脈沖，每一次重復直接關系到發(fā)射機和接收機之間的距離。脈沖串提供給各自的計數(shù)器，然后利用計數(shù)器所測得的數(shù)據(jù)進行距離的測量。 </p><p>　　出版日期： 1995年8月15日</p><p>　　主審查員：羅保.伊恩j. </p><p><b>　　一、背景發(fā)明</b></p><p>

3、;　　本發(fā)明涉及到儀器的測量距離，更特別是，這種儀器傳送超聲波于兩點之間。 精密機器設備必須校準。在過去，這已經(jīng)可以利用卡鉗，微米等工具來校準機械設備。不過，使用這些工具都不能實現(xiàn)自動化。據(jù)了解，該兩點之間距離可以通過測量波在兩點之間的傳播時間來確定。這樣一個類型的波可以是是一種超聲波，或聲，或波。當超聲波傳播于兩點之間的時候，兩個點之間的距離可以通過由超聲波波速乘以超聲波傳播的時間，在合適的分離的兩點。因此，這是一個發(fā)明提供儀器利用超

4、聲波準確測量兩點之間距離的方法。 </p><p>　　當距離適當?shù)膬蓚€點之間的介質(zhì)是空氣的時候，聲速只取決于溫度和空氣相對濕度。因此，這個發(fā)明的進一步目標是，目前的發(fā)明提供儀器的方法如所描述的一樣是獨立于溫度和濕度的變化的。 </p><p><b>　　二、綜述發(fā)明</b></p><p>　　前述的和額外的目標已經(jīng)實現(xiàn)了根據(jù)這些原則的這項

5、發(fā)明提供距離測量儀器，其中包括一個參考的單元和測量單元。參考和測量單元是相同的，每個單元都包括了一個電聲波的發(fā)射機和接收機。參考單元的發(fā)射器和接收器之間的間隔是一個固定的參考距離，然而測量單元的發(fā)射機和接收機的間距才是我們所要測量的部分。在每一個單元中，發(fā)射機和接收機都連接了一個反饋環(huán)路，以使發(fā)射機產(chǎn)生能由接收器接收的聲波生脈沖，然后由接收機轉(zhuǎn)換成一個電脈沖反饋到發(fā)射機，使產(chǎn)生一系列重復脈沖的結果。脈沖重復率是成反比關系發(fā)射器和接收器之

6、間的距離。在每一個單元，脈沖被用來提供給一個計數(shù)器。由于參考的距離是已經(jīng)知道的了，所以計數(shù)器所輸出的數(shù)據(jù)被利用來確定所期望測得的距離。由于溫度和濕度的變化，這兩方面都會造成相同的影響，利用計數(shù)器所提供的數(shù)據(jù)，這樣的測量對于溫度和濕度引起的變化一樣是沒有辦法避免的。 </p><p><b>　　三、簡要圖紙說明</b></p><p>　　通過讀接了下來的說明前面的敘

7、述將變得更加明顯，這個關于電路原理圖的描述在與這項發(fā)明的相關規(guī)律保持了相當?shù)囊恢滦浴?</p><p><b>　　四、詳細說明</b></p><p>　　根據(jù)現(xiàn)在的繪圖，可以得出以下結論，測量單元10和參考單元12都聯(lián)結起來組成了可以利用的單元14 。測量單元10包括了一個電信號發(fā)射機16和一個電信號接收機18 。發(fā)射器16包括了夾著一對電極22和24的壓電材料2

8、0。同樣，接收機18包括了夾著一對電極28和30的壓電材料26。眾所周知，通過利用電極22和24之間產(chǎn)生的電場，壓電材料20將產(chǎn)生壓力 。如果該電場產(chǎn)生變化的話，例如通過利用一個電脈沖，就會產(chǎn)生一個聲波32。因此，進一步得知，當聲波對接收器18起作用的時候 ，這時會引起接收器上的壓變材料26產(chǎn)生機械變形，同時產(chǎn)生一個電信號通過28和30這一對電極 。雖然已經(jīng)對壓電傳感器作出了說明，但是其他的電聲裝置也可利用，例如，有關靜電的，駐極體或電

9、磁類型的。 </p><p>　　如圖所示，接收機的電極28和30將與放大器34的輸入端相連接，同時，放大器的其輸出端與探測器36相連接。探測器36被用于提供一個信號給脈沖發(fā)生器38，當放大器34的輸出已經(jīng)超過預定的等級。脈沖發(fā)生器38然后產(chǎn)生一個觸發(fā)脈沖，這是提供給脈沖發(fā)生器40 。在為了提高靈敏度，該系統(tǒng)的傳感器16和18歲通常情況下都是保持運作的。根據(jù)相應的需要，本發(fā)明提供了一個連續(xù)波振蕩器42，他能持續(xù)的

10、產(chǎn)生一個固定頻率的連續(xù)振蕩信號，最好是同傳感器16和18能接收到的固定頻率一致 。這個振蕩信號被用來提供給調(diào)制器44 。為了使發(fā)射機16有效的工作 ，最好的做法是提供幾個周期的共振頻率信號，而不是一個單脈沖或單周期。因此，在這里使用了脈沖發(fā)生器40，用于回應每一個觸發(fā)脈沖，提供一個控制脈沖給調(diào)制器44，讓調(diào)制器44有一個與來自于振蕩器42的周期振蕩信號預定的相同時間 。這樣的控制脈沖能使調(diào)制器44傳送一個周期的突破口以觸發(fā)發(fā)射機16。

11、</p><p>　　當電源被用于描述的電路，有相當大的噪音輸入到放大器34 ，以至于其輸出觸發(fā)脈沖發(fā)生器40引起正當周期變化，這個振蕩周期是用來提供給發(fā)射器16的電極22和24。發(fā)射器16因此產(chǎn)生聲波32并作用于接收器18 。接收器18 然后產(chǎn)生一個電脈沖，輸入放大器的34 ，這再次觸發(fā)脈沖發(fā)生器40 。這個周期繼續(xù)循環(huán)，使重復的一系列觸發(fā)脈沖作用于脈沖發(fā)生器38的輸出 。這脈沖串被用于計數(shù)器46，以及脈沖發(fā)生

12、器40 。 </p><p>　　發(fā)射機16和接收機18中間的間隔距離 D 它是我們想要測量的數(shù)據(jù)。傳播時間T是聲波傳播于之間的距離除以速度而得出來的，通過公式T=D/V 。速度是在發(fā)射機16和接收機18之間這段空氣中傳播的速度，計數(shù)器46測量觸發(fā)脈沖的重復率，這是因為脈沖等于的1/T。因此，重復率是等于V/D。聲波的速度通常受到空氣的濕度和溫度的影響，例子如下：##equ1##其中T是溫度，P是水汽局部的壓力，

13、H是大氣壓強， γ和γ是比例不同壓力下在熱水汽和干燥的空氣不同的比熱容。因此，觸發(fā)脈沖的重復率測被計數(shù)器46測量得相當?shù)臏蚀_ ，但是聲速受到溫度和濕度的影響，使測量的距離d無法被準去的確定。 </p><p>　　根據(jù)這項發(fā)明的基本原理，需要利用參考單元12 。參考單元12同測量單元10基本上是一樣的，其中，包括一電發(fā)射機50，以及在壓電材料52之間的一對電極的54和56 。接收機58 ，其中包括壓電材料60之間

14、的一對電極62和64 。再次，傳感器除了其他類型壓電也可以被利用。發(fā)射機50和接收機58之間的距離都是已知的且固定的,設為DR。電極62和64連接到放大器66的輸入端 ，其輸出連接到探測器68 。探測器68的輸出端連接到脈沖發(fā)生器70，脈沖發(fā)生器70產(chǎn)生觸發(fā)脈沖。觸發(fā)脈沖應用到脈沖發(fā)生器72以控制調(diào)制器74通過連續(xù)振蕩器76傳送一段脈沖串傳遞至發(fā)射機50 。來自于脈沖發(fā)生器70的觸發(fā)脈沖也用于計數(shù)器78。 </p><

15、;p>　　最好是所有的傳感器16 ，18 ，50和58具有相同的共振頻率。因此，振蕩器42和76都工作在同樣的頻率上，脈沖發(fā)生器40和72產(chǎn)生相同帶寬的輸出脈沖。 </p><p>　　按照慣例，測量單元10和參考單元12空間上很接近，使該聲速在這兩個單元是相同的。雖然測量單元10和參考單元12的脈沖重復率各自依賴于各自的溫度和濕度，能證明的距離D來衡量。可以得出測量單元和參考單元之間的聯(lián)系如下：i D=D

16、 R (1/t R )/(1/t)，tR是指的參照單元聲波傳播于固定空間的時間。這個關系與空氣的溫度和濕度都是無關的。 </p><p>　　因此，計數(shù)器46和計數(shù)器78的輸出被用來提供來作為微處理器90，作為方法14。微處理器90可通過編寫程序來提供輸出。這個輸出與計數(shù)器46和78的輸出是成比例的，反過來也同測量單元10和參考單元12各自的觸發(fā)脈沖串成比例。如所敘述的一樣，這些比率是不依賴于溫度和濕度的，因為

17、參考距離DR是已知的，提供了一個準確的距離D的參考。這個利用方法12更進一步的包括了被微處理器控制的顯示器92，所以設備可以確定距離D。</p><p>　　試驗還表明當發(fā)射機和接收機傳感器之間的距離太小的時候，聲波的反射在傳感器表面的效果不是很明顯，以至于極大的影響了測量的精度。根據(jù)這種情況，使傳感器分開有一個相當?shù)淖钚【嚯x，最合適是4英寸。</p><p><b>　　附件2

18、：外文原文</b></p><p>　　Ultrasonic distance meter</p><p>　　Abstract:An ultrasonic distance meter cancels out the effects of temperature and humidity variations by including a measuring unit and

19、 a reference unit. In each of the units, a repetitive series of pulses is generated, each having a repetition rate directly related to the respective distance between an electroacoustic transmitter and an electroacoustic

20、 receiver. The pulse trains are provided to respective counters, and the ratio of the counter outputs is utilized to determine the distance being </p><p>　　Publication Date:08/15/1995 </p><p>　　

21、Primary Examiner:Lobo, Ian J.</p><p>　　1、BACKGROUND OF THE INVENTION </p><p>　　This invention relates to apparatus for the measurement of distance and, more particularly, to such apparatus which

22、 transmits ultrasonic waves between two points. </p><p>　　Precision machine tools must be calibrated. In the past, this has been accomplished utilizing mechanical devices such as calipers, micrometers, and t

23、he like. However, the use of such devices does not readily lend itself to automation techniques. It is known that the distance between two points can be determined by measuring the propagation time of a wave travelling b

24、etween those two points. One such type of wave is an ultrasonic, or acoustic, wave. When an ultrasonic wave travels between two poi</p><p>　　When the medium between the two points whose spacing is being meas

25、ured is air, the sound velocity is dependent upon the temperature and humidity of the air. It is therefore a further object of the invention, present invention to provide apparatus of the type described which is independ

26、ent of temperature and humidity variations. </p><p>　　2、SUMMARY OF THE INVENTION </p><p>　　The foregoing and additional objects are attained in accordance with the principles of this invention b

27、y providing distance measuring apparatus which includes a reference unit and a measuring unit. The reference and measuring units are the same and each includes an electroacoustic transmitter and an electroacoustic receiv

28、er. The spacing between the transmitter and the receiver of the reference unit is a fixed reference distance, whereas the spacing between the transmitter and receiver of the mea</p><p>　　3、BRIEF DESCRIPTION

29、OF THE DRAWINGS </p><p>　　The foregoing will be more readily apparent upon reading the following description in conjunction with the drawing in which the single FIGURE schematically depicts apparatus constru

30、cted in accordance with the principles of this invention. </p><p>　　4、DETAILED DESCRIPTION </p><p>　　Referring now to the drawing, there is shown a measuring unit 10 and a reference unit 12, bot

31、h coupled to a utilization means 14. The measuring unit 10 includes an electroacoustic transmitter 16 and an electroacoustic receiver 18. The transmitter 16 includes piezoelectric material 20 sandwiched between a pair of

32、 electrodes 22 and 24. Likewise, the receiver 18 includes piezoelectric material 26 sandwiched between a pair of electrodes 28 and 30. As is known, by applying an electric field across th</p><p>　　As shown,

33、the electrodes 28 and 30 of the receiver 18 are coupled to the input of an amplifier 34, whose output is coupled to the input of a detector 36. The detector 36 is arranged to provide a signal to the pulse former 38 when

34、the output from the amplifier 34 exceeds a predetermined level. The pulse former 38 then generates a trigger pulse which is provided to the pulse generator 40. In order to enhance the sensitivity of the system, the trans

35、ducers 16 and 18 are resonantly excited. There is </p><p>　　When electric power is applied to the described circuitry, there is sufficient noise at the input to the amplifier 34 that its output triggers the

36、pulse generator 40 to cause a burst of oscillating cycles to be provided across the electrodes 22 and 24 of the transmitter 16. The transmitter 16 accordingly generates an acoustic wave 32 which impinges upon the receive

37、r 18. The receiver 18 then generates an electrical pulse which is applied to the input of the amplifier 34, which again causes trigge</p><p>　　The transmitter 16 and the receiver 18 are spaced apart by the d

38、istance "D" which it is desired to measure. The propagation time "t" for an acoustic wave 32 travelling between the transmitter 16 and the receiver 18 is given by: t=D/V s </p><p>　　where

39、 V s is the velocity of sound in the air between the transmitter 16 and the receiver 18. The counter 46 measures the repetition rate of the trigger pulses, which is equal to 1/t. Therefore, the repetition rate is equal t

40、o V s /D. The velocity of sound in air is a function of the temperature and humidity of the air, as follows: ##EQU1## where T is the temperature, p is the partial pressure of the water vapor, H is the barometric pressure

41、, Γ w and Γ a are the ratio of constant pressure specif</p><p>　　In accordance with the principles of this invention, a reference unit 12 is provided. The reference unit 12 is of the same construction as the

42、 measuring unit 10 and therefore includes an electroacoustic transmitter 50 which includes piezoelectric material 52 sandwiched between a pair of electrodes 54 and 56, and an electroacoustic receiver 58 which includes pi

43、ezoelectric material 60 sandwiched between a pair of electrodes 62 and 64. Again, transducers other than the piezoelectric type can be uti</p><p>　　Preferably, all of the transducers 16, 18, 50 and 58 have t

44、he same resonant frequency. Therefore, the oscillators 42 and 76 both operate at that frequency and the pulse generators 40 and 72 provide equal width output pulses. </p><p>　　In usage, the measuring unit 10

45、 and the reference unit 12 are in close proximity so that the sound velocity in both of the units is the same. Although the repetition rates of the pulses in the measuring unit 10 and the reference unit 12 are each tempe

46、rature and humidity dependent, it can be shown that the distance D to be measured is related to the reference distance D R as follows: i D=D R (1/t R )/(1/t) where t R is the propagation time over the distance D R in the

47、 reference unit 12. This rela</p><p>　　Thus, the outputs of the counters 46 and 78 are provided as inputs to the microprocessor 90 in the utilization means 14. The microprocessor 90 is appropriately programm

48、ed to provide an output which is proportional to the ratio of the outputs of the counters 46 and 78, which in turn are proportional to the repetition rates of the respective trigger pulse trains of the measuring unit 10

49、and the reference unit 12. As described, this ratio is independent of temperature and humidity and, since the re</p><p>　　Experiments have shown that when the distance between the transmitting and receiving

50、transducers is too small, reflections of the acoustic wave at the transducer surfaces has a not insignificant effect which degrades the measurement accuracy. Accordingly, it is preferred that each transducer pair be sepa