超聲波測(cè)距儀畢業(yè)論文外文文獻(xiàn)翻譯及原文

1、畢業(yè)設(shè)計(jì)（論文） 外文文獻(xiàn)翻譯文獻(xiàn)、資料中文題目：超聲波測(cè)距儀文獻(xiàn)、資料英文題目：文獻(xiàn)、資料來(lái)源： 文獻(xiàn)、資料發(fā)表（出版）日期：院（部）：專(zhuān) 業(yè)： 班 級(jí)：姓 名：學(xué) 號(hào)：指導(dǎo)教師: 翻譯日期:2017. 02. 14英文文獻(xiàn)翻譯ultrasonic distance meter文獻(xiàn)來(lái)源:united states patent 5442592作 者：lobo，ian j.（羅保伊恩j.ultrasonic distance meterabstract:an ultrasonic distance meter cancels out the effects of temperature and

2、 humidity variations by including a measuring unit and 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 receiver. the pulse trains

3、 are provided to respective counters，and the ratio of the counter outputs is utilized to determine the distance being measured.一、background of the inventionthis invention relates to apparatus for the measurement of distance and, more particularly, to such apparatus which transmits ultrasonic waves b

4、etween two points.precision machine tools must be calibrated. in the past，this has been accomplished utilizing mechanical devices such as calipers, micrometers, and the like. however，the use of such devices does not readily lend itself to automation techniques. it is known that the distance between

5、two points can be determined by measuring the propagation time of a wave travelling between those two points. one such type of wave is an ultrasonic，or acoustic, wave. when an ultrasonic wave travels between two points，the distance between the two points can be measured by multiplying the transit ti

6、me of the wave by the wave velocity in the medium separating the two points. it is therefore an object of the present invention to provide apparatus utilizing ultrasonic waves to accurately measure the distance between two points.when the medium between the two points whose spacing is being measured

7、 is air，the sound velocity is dependent upon the temperature and humidity of the air. it is therefore a further object of the，present invention to provide apparatus of the type described which is independent of temperature and humidity variations.二、summary of the inventionthe foregoing and additiona

8、l objects are attained in accordance with the principles of this invention by 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 receiver.

9、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 measuring unit is the distance to be measured. in each of the units，the transmitter and receiver are coupled by a feedback loop wh

10、ich causes the transmitter to generate an acoustic pulse which is received by the receiver and converted into an electrical pulse which is then fed back to the transmitter，so that a repetitive series of pulses results. the repetition rate of the pulses is inversely related to the distance between th

11、e transmitter and the receiver. in each of the units，the pulses are provided to a counter. since the reference distance is known，the ratio of the counter outputs is utilized to determine the desired distance to be measured. since both counts are identically influenced by temperature and humidity var

12、iations，by taking the ratio of the counts, the resultant measurement becomes insensitive to such variations.三、detailed descriptionreferring now to the drawing，there is shown a measuring unit 10 and a reference unit 12，both coupled to a utilization means 14. the measuring unit 10 includes an electroa

13、coustic transmitter 16 and an electroacoustic receiver 18. the transmitter 16 includes piezoelectric material 20 sandwiched between a pair of 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

14、 an electric field across the electrodes 22 and 24, stress is induced in the piezoelectric material 20. if the field varies, such as by the application of an electrical pulse，an acoustic wave 32 is generated. as is further known，when an acoustic wave impinges upon the receiver 18, this induces stres

15、s in the piezoelectric material 26 which causes an electrical signal to be generated across the electrodes 28 and 30. although piezoelectric transducers have been illustrated, other electroacoustic devices may be utilized，such as, for example, electrostatic, electret or electromagnetic types.as show

16、n，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 the output from the amplifier 34 exceeds a predetermined level. the pulse form

17、er 38 then generates a trigger pulse which is provided to the pulse generator 40. in order to enhance the sensitivity of the system，the transducers 16 and 18 are resonantly excited. there is accordingly provided a continuous wave oscillator 42 which provides a continuous oscillating signal at a fixe

18、d frequency，preferably the resonant frequency of the transducers 16 and 18. this oscillating signal is provided to the modulator 44. to effectively excite the transmitter 16, it is preferable to provide several cycles of the resonant frequency signal，rather than a single pulse or single cycle. accor

19、dingly，the pulse generator 40 is arranged, in response to the application thereto of a trigger pulse， to provide a control pulse to the modulator 44 having a time duration equal the time duration of a predetermined number of cycles of the oscillating signal from the oscillator 42. this control pulse

20、 causes the modulator 44 to pass a burst” of cycles to excite the transmitter 16.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 pulse generator 40 to cause a burst of oscillating cycles to be provided

21、across the electrodes 22 and 24 of the transmitter 16. the transmitter 16 accordingly generates an acoustic wave 32 which impinges upon the receiver 18. the receiver 18 then generates an electrical pulse which is applied to the input of the amplifier 34, which again causes triggering of the pulse ge

22、nerator 40. this cycle repeats itself so that a repetitive series of trigger pulses results at the output of the pulse former 38. this pulse train is applied to the counter 46, as well as to the pulse generator 40.the transmitter 16 and the receiver 18 are spaced apart by the distance "d” which

23、 it is desired to measure. the propagation time v for an acoustic wave 32 travelling between the transmitter 16 and the receiver 18 is given by: t=d/v s where 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 tr

24、igger pulses, which is equal to 1/t. therefore，the repetition rate is equal to v s /d. the velocity of sound inair is a function of the temperature and humidity of the air，as follows: #equ 1 # where t is the temperature，p is the partial pressure of the water vapor, h is the barometric pressure, r w

25、and v a are the ratio of constant pressure specific heat to constant volume specific heat for water vapor and dry air, respectively. thus，although the repetition rate of the trigger pulses is measured very accurately by the counter 46, the sound velocity is influenced by temperature and humidity so

26、that the measured distance d cannot be determined accurately.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 measuring unit 10 and therefore includes an electroacoustic transmitter 50 which includes piezoel

27、ectric material 52 sandwiched between a pair of electrodes 54 and 56, and an electroacoustic receiver 58 which includes piezoelectric material 60 sandwiched between a pair of electrodes 62 and 64. again，transducers other than the piezoelectric type can be utilized. the transmitter 50 and the receive

28、r 58 are spaced apart a known and fixed reference distance "dr”. the electrodes 62 and 64 are coupled to the input of the amplifier 66, whose output is coupled to the input of the detector 68. the output of the detector 68 is coupled to the pulse former 70 which generates trigger pulses. the tr

29、igger pulses are applied to the pulse generator 72 which controls the modulator 74 to pass bursts from the continuous wave oscillator 76 to the transmitter 50. the trigger pulses from the pulse former 70 are also applied to the counter 78.preferably, all of the transducers 16，18，50 and 58 have the s

30、ame 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.in usage，the measuring unit 10 and the reference unit 12 are in close proximity so that the sound velocity in both of the units is the same

31、. although the repetition rates of the pulses in the measuring unit 10 and the reference unit 12 are each temperature 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 tim

32、e over the distance d r in the reference unit 12. this relationship is independent of both temperature and humidity.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 programmed to provide an

33、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 and the reference unit 12. as described, this ratio is independent of temperature and humidity an

34、d, since the reference distance d r is known, provides an accurate representation of the distance d. the utilization means 14 further includes a display 92 which is coupled to and controlled by the microprocessor 90 so that an operator can readily determine the distance d.experiments have shown that

35、 when the distance between the transmitting and receiving 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 separated by at least a cert

36、ain minimum distance, preferably about four inches.u!accordingly，there has been disclosed improved apparatus for the measurement of distance utilizing ultrasonic waves. while an illustrative embodiment of the present invention has been disclosed herein，it is understood that various modifications and

37、 adaptations to the disclosed embodiment will be apparent to those of ordinary skill in the art and it is intended that this invention be limited only by the scope of the appended claims.a principle of ultrasonic distancemeasurement1，the principle of piezoelectric ultrasonic generatorpiezoelectric u

38、ltrasonic generator is the use of piezoelectric crystal resonators to work. ultrasonic generator, the internal structure as shown in figure 1，it has two piezoelectric chip and a resonance plate. when itfs two plus pulse signal，the frequency equal to the intrinsic piezoelectric oscillation frequency

39、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 of piezoelectric chip, the me

40、chanical energy is converted to electrical signals，then it becomes the ultrasonic receiver.2, the principle of ultrasonic distance measurementultrasonic 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，

41、 obstacles on his way to return immediately, the ultrasonic reflected wave received by the receiver immediately stop the clock. ultrasound 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

42、)，that is: s = 340t / 2五、ultrasonic ranging system for the secondcircuit designsystem 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

43、4k of rom，to facilitate programming. circuit schematic diagram shown in figure 2. draw only the front range of the circuit wiring diagram，left and right in front of ranging ranging circuits and the same circuit, it is omitted.l，40 khz ultrasonic pulse generated with the launchranging system using th

44、e ultrasonic sensor of piezoelectric ceramic 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 200mshere: cpl pl.o; output 40khz square wavenop;nop;nop;dj

45、nz 14h，here;retranging 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 pulse output signal， after amplification transistor t，the drive to launch the first ultrasonic ucm40t， issued 40khz ultrasonic pulse, and the

46、 continued launch of 200ms. ranging the right and the left side of the circuit，respectively, then input port pl.l and pl.2, the working principle and circuit in front of the same location.2, reception and processing of ultrasonicused to receive the first launch of the first pair ucm40r，the ultrasoni

47、c 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 fd = 1/1.1r8c3, capacitor c4 determine their target bandwidth. r8-condi

48、tioning 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 output port into interrupt the highest p

49、riority，right or left location of the output circuit with output gate ic3a access inti port single-chip，while single-chip pl.3 and pl. 4 received input ic3a， interrupted by the process to identify the source of inquiry to deal with，interrupt priority level for the first left right after. part of the

50、 source code is as follows:receive 1: push psw push accclr exl; related external interrupt 1jnb pl.l, right; pl.l pin to 0，ranging from right to interrupt service routine circuitjnb pi.2, left; pl.2 pin to 0, to the left ranging circuit interrupt service routine return: setb ex1; open external inter

51、rupt 1 pop? accpop? psw retiright: .?; right location entrance circuit interrupt service routine? ajmp? returnleft:left ranging entrance circuit interrupt service routine? ajmp? return3, the calculation of ultrasonic propagation timewhen you start firing at the same time start the single-chip circui

52、try within the timer to, 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 into or inti interrupt request generates a signal, single

53、-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 code is as follows:receiveo: push pswpush accclr exo; related external interrupt 0? mov r7, tho; rea

54、d the time valuemov r6, tlo?clrcmov a, r6subb a, # obbh; calculate the time differencemov 31h, a; storage resultsmov a, r7subb a, # 3chmov 30h, a?setb exo; open external interrupt 0pop acc?poppswreti六、the ultrasonic ranging system softwaredesignsoftware is divided into two parts, the main program an

55、d interrupt service routine, shown in figure 3 (a) (b) (c) below. completion of the work of the main program is initialized，each sequence of ultrasonic transmitting and receiving control.interrupt service routines from time to time to complete three of the rotation direction of ultrasonic launch，the

56、 main external interrupt service subroutine to read the value of completion time，distance calculation, the results of the output and so on.七、conclusionsrequired 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 repro

57、ducibility. 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 t

58、he transistor amplifier circuit， because the magnification well，cx20106 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.超聲波測(cè)距儀摘要：提出了一種超聲波測(cè)距儀來(lái)抵消的影響溫度和濕度的變化，鈕括測(cè)量 單元和參考資料。在每一個(gè)單位，重復(fù)的一系列脈沖的產(chǎn)生，每有一個(gè)重復(fù)率， 直接關(guān)系到各自之間的距離，發(fā)射機(jī)和接收機(jī)。脈沖提供給各自的主機(jī)，和比例 的反產(chǎn)出是利用確定的距離被衡量的。背景發(fā)明本發(fā)明涉及到儀器的測(cè)量距離，更特別是，這種儀器傳送超聲波兩點(diǎn)之間。 精密機(jī)床必須校準(zhǔn)。在過(guò)去，這已經(jīng)完成利用機(jī)械設(shè)備，如卡鉗，微米等。不過(guò), 使用這種裝置并不容易本身自動(dòng)化技術(shù)。據(jù)了解，該兩點(diǎn)之間距離才能確定通過(guò) 測(cè)量傳播時(shí)間的浪潮往返那些兩點(diǎn)。這樣一個(gè)類(lèi)型的波是一種超聲波，或聲，海 浪。當(dāng)超聲波旅行兩點(diǎn)之間，距離兩個(gè)點(diǎn)之間可以衡量乘以過(guò)境的時(shí)間波由波速， 在中期分開(kāi)兩點(diǎn)。因此，這