外文翻譯--基于微機控制器的超聲波測距設計

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1、　　Available online at www.sciencedirect.com　　Physics Procedia 25 (2012) 1732 – 1737　　中文3380字　　2012 International Conference on So

2、lid State Devices and Materials Science　　Design and Simulation of the Ultrasonic Rangefinder Based on Micro-controller　　SHI Yanbina, LIU Hong, HAO Xue a　　Avi

3、ation University of Air force, Changchun, 130022, China　　Abstract　　This paper describes the principle and techniques of ultrasonic rangefinder based on micro-c

4、ontroller AT89C2051. The performance characteristics of the ultrasonic rangefinder are studied theoretically and experimentally. The primary objective of the study was to determine the hardware principle circuit and the

5、 main software design, the computed simulation by Pspice is provided for the key part of the hardware circuit. In this paper it is demonstrated that this type of the ultrasonic rangefinder　　© 20

6、12 Published by Elsevier B.V. Selection and/or peer-review under responsibility of Garry Lee　　Open access under CC BY-NC-ND license.　　Keywords: Ultrasonic rangefinder; DDS; signa

7、l source; micro-controller　　1. Introduction　　The ultrasonic has many characteristics such as the strong directive property, the slow energy consumption, the long propagation dist

8、ance in the medium and so on. Because each medium presents certain impedance to the propagation for the ultrasonic when the ultrasonic affects to two medium interfaces, if the difference of the acoustic impedance b

9、etween these two medium is very big, the ultrasonic can reflect from the contact surface, thus the ultrasonic can be used in the　　415Pa·s/m, and the acoustic impedance rate of

10、 the water is 1.48×106 Pa·s/m, the acoustic impedance rate　　of the steel is 4.5×107 Pa·s/m, therefore the distance gauge and the position measuring instrument and so on between

12、election and/or peer-review under responsibility of Garry Lee　　Open access under CC BY-NC-ND license. doi:10.1016/j.phpro.2012.03.303　　ultrasonic. The principle of the rangefinde

13、r is the ultrasonic launch some direction ultrasonic wave, at the same time start time, the ultrasonic propagates in the air, bumps into the obstacle to reflect on the way, the ultrasonic wave receiver receives the refle

14、cted wave, and stops time immediately, records the time according to the timer, the distance between the emission point and obstacle can be calculated. In this paper, takes the AT89C2051 one-chip micro-controller as the

15、core, utilizes th　　2. Systematic characteristics describe and technical feature　　The main function of the rangefinder is carries on the distance measurement in the 6m range. Its

16、characteristic is: its electric circuit is simple, and the volume is small; Used the micro-controller technology, it has high reliability and measuring accuracy; it adopts the loss consumed power component, which reduces

17、 the breakdown formation rate; it takes the liquid crystal digital display, which easy to use.　　The main technical performances of the rangefinder:　　x Measurement range: 0.7~6m;

18、　　x Measuring error: δ≦1.7%;　　x Resolution: 0.01m;　　x Main hardware: AT89C2051 micro-controller, ultrasonic detecting head (UCM-R40 and UCM-T40), characte

19、r liquid crystal display module (TR0802B).　　3. System design and improving　　Fig. 1.system structural block diagram　　The structural block diagram of the syste

20、m is shown as Fig. 1. When switching on the working power, the micro-controller data processing unit initializes the square wave which forms 40 KHz, push the PTT button, it transmits the sinusoidal wave; the er begins to

21、 count at the same time, the ultrasonic carries on power amplification through the power amplifier, launched by the ultrasonic launcher. When it meet the reflector, the reflector reflects the return wave echo at once, th

22、e receiver receives　　S = v(t-t0 )　　2　　(1)　　The transmit speed of the ultrasonic in the air is:<

23、/p>　　v=v0　　1+T / 273　　(2)　　3.1. Hardware design　　The system hardw

24、are architecture divides into four parts: 5V power source; micro-controller circuit for data processing and demonstration part; Ultrasonic transmitter part; receiver and amplifier unit. Fig. 2 shows the circuit diagram o

25、f the ultrasonic rangefinder based on micro-controller.　　AN1　　M1　　RT0802B<b&

26、gt;　　?? ?? ??　　GND　　U1C　　5 6　　4069<

27、;p>　　U1B　　3 4　　4069　　U1A　　1

28、　　4069　　U1E　　A1　　SEND　　R1 ??? ?</p&g

29、t;　　51　　VCC　　C1　　0.1uF　　RW1<

30、;/p>　　10K　　?????　　U1D　　9 8 　　11

31、;　　4069　　U1F　　GND　　VCC　　4069 13</b&g

32、t;　　4069　　RS R/W　　E DB0　　U2　　11

33、 P3.7　　12 P1.0(AIN0)　　GND (T1)P3.5　　GND　　10　　9</b&g

34、t;　　C3 15P　　C5　　33P 　　R2 C6

35、　　VCC　　R14　　DB1 13　　DB2 14　　P1.1(AIN1)　　(T0)P3.4 8

36、;　　7　　GND　　100K　　R4　　10K</p

37、>　　300K　　C8　　100P　　U3D　　A2&

38、lt;/p>　　RECEIVE　　DB3 15　　DB4 16　　P1.2　　P1.3</p

39、>　　P1.4　　(INT1)P3.3　　(INT0)P3.2　　XTAL1　　6 C4

40、　5 15P　　U3C　　10uF　　U3A　　C10<p

41、>　　2　　12　　R17 14　　DB5 17　　DB6 18<b&

42、gt;　　P1.5　　XTAL2 4　　3　　CY1　　9 1　　8

43、3 100P　　6.8K 13　　VCC　　DB7 19　　20<b&

44、gt;　　C2　　P1.6　　P1.7　　VCC　　AT89C2051<

45、;p>　　(TXD)P3.1 (RXD)P3.0 2　　RST/VPP 1　　AN2　　VCC　　10<

46、;/p>　　LM324　　R8　　10K　　LM324　　R15</

47、b>　　300K　　R16　　6.8K　　LM324

48、　+9V　　U4 78L05　　1 Vin　　GND　　+5V　　0.1uF<

49、;/b>　　3　　VCC VCC　　C12　　1uF

50、　D1　　R5　　10K　　GND　　R6

51、;　　10K　　1　　U5A　　2　　3

52、　　R7　　10K　　GND　　U3B　　CN1<b

53、>　　1　　2　　C11　　47uF　　GND<

54、;b>　　C7　　10uF　　1N4148　　GND　　TLC393&

55、lt;p>　　C9　　100P　　GND　　R3　　100K</p&g

56、t;　　VCC　　VCC　　R9　　10k　　5</p

57、>　　R10 6　　10k　　GND　　7 2.5V　　LM324 C13<p&g

58、t;　　0.1u　　GND　　R11　　10K　　5<

59、;p>　　R12 6　　10K　　U5B　　7　　R13

60、;　　10K　　TLC393　　GND　　Fig. 2. circuit diagram of the ultrasonic rangefinder based on micro-controller

61、　　The power unit uses three terminal integration regulator 78L05, which provides the stable +5V voltage for the micro-controller circuit and the amplifier. The micro-controller circuit uses the low v

62、oltage, high performance CMOS 8 machine AT89C2051 which American ATMEL Corporation produces, it is compatible with the industry standard MCS-51 instruction and the pin, thus is one kind of function formidable micro contr

63、oller, has provided a highly nimble effective solution to the very many embedded co　　RT0802B is the display unit; the key AN1 is used for control the back light of the RT0802B; RW1 is used for adjust

64、 the demonstration contrast gradient; the key AN2 is used for control the work switch condition of the rangefinder.　　The transmission circuit is composed by the CD4069 phase reverser, this circuitry

65、is simple (see also schematic diagram), U1B and U1A, U1E and U1F joining-up enhance the output current; the output voltage phases of the 4th, 2nd pin and 10th, 12th pin are opposite. Thus, the transmitter may obtain the

66、peak value is the 9V AC sine signal (the Q value of the ultrasonic wave transmitter is very high, only the fundamental wave signal has an effect, the higher harmonic does not have influence), which

67、　The pre-amplifier selects the general low power consumed integration operational amplifier LM324, receives the weak signal by the ultrasonic wave acceptor and carries on the enlargement.U3B outputs the<p&

68、gt;　　2.5V voltage as the voltage follower to provide the bias for other amplifiers; Considered the output impedance of the ultrasonic receiver is high, U3D design as the voltage follower to enhance the input impedance of

69、 the amplifier circuit; U3A is composed the active bandpass filter, its center frequency is　　40KHz and the gain is 20, it may filter each kind of unwanted signal; The U3C composites the inverting amp

70、lifier, its gain is 10. So the total gain of the receiver is 200. The LM393 low power consumed two- circuit double pole comparator is the echo shaping unit, it reshapes the received signal, and outputs the square-wave to

71、 the micro-controller.　　Where, T is the absolute temperature, v0=331.4m / s , S is the probing range, v is propagation　　velocity of the ultrasonic. Because transmissio

72、n speed of the ultrasonic is influenced by the temperature　　and the medium. t is the recording time, t0　　is delay of the system. If the rangefinder precision request is

73、　　high, it may be adjusted through the temperature or the experience compensation measure. If the precision　　is not very high for rangefinder, generally it can be 340m/s.<p&

74、gt;　　3.2. Hardware simulation　　Using the simulation method while design the electric circuit, which is advantageous to optimized design and debugging. After completes the initially integrated circuit

75、 design, the hardware electric circuit debugging work mainly concentrates on the active bandpass filter. In order to debug conveniently, in the design first used Pspice to carry on the simulation to this electric circuit

76、, by determined the concrete parameter, enhances the system performance, and simplifies the debugging works. Fig　　3.3. Software design　　The software include two parts, they are t

77、he master routine and the interrupt service, as shown in Fig 4. The master routine completes the initialization, transmit the ultrasonic and the control of the receive sequence. The timing interrupt service subroutine co

78、mpletes the ultrasonic echo receiving; the external interrupt service subroutine mainly complete the time value reading, distance computation, result work and so on.　　x The 40kHz pulse production an

79、d the ultrasonic transmitting　　The ultrasonic sensor in the rangefinder uses the piezoelectricity ceramics sensor UCM40, its working voltage is the 40kHz pulse signal, which is generated by the follo

80、wing procedure stored in the micro- controller.　　Fig. 3.Design electric circuit in PspiceFig. 4. Simulati on result in Pspice　　Fig. 5 Software flow chart　　T

81、he input terminal of the range-measuring circuit connects to the P3.0 port of the micro-controller. After carries out above procedure, the micro-controller outputs the 40kHz pulse signal in the P3.0 port, and this signal

82、 is enlarged by LM4069, drivers the ultrasonic detecting head UCM40T, sends out the　　40kHz pulse ultrasonic, and keeps 200ms continually.　　x The ultrasonic wave receiving and pr

83、ocessing　　The receiving detecting head uses the UCM40R, which changes the ultrasonic modulation pulse to the alternating voltage signal, and then add to U2B after the operational amplifier U2A.

84、U2B and the periphery electric circuit composes the bandpass filter, which carries on the filter, reshaping processing to the receive signal. The center frequency of the signal is , delivers to micro-controller.</p&g

85、t;　　Starts the internal timer T0 of micro-controller when starts the transmission circuit, and receives the reflected wave using the timer counting function recording ultrasonic wave launch time the time. When

86、 the rangefinder receives the reflected ultrasonic wave, the out-port of the accepting circuit has a negative jump, produces an interrupt request signal in INT0 or the INT1, the micro-controller responds the external int

87、errupt request, carries out the external interrupt service subroutine, read　　x Improve the measure precision　　Because of the influence by the temperature to the speed and the ti

88、me, the precision of this system is limited. So we can improve the design according to paper [5]. The propagation velocity value has made revision according to the experience of the ultrasonic wave in the air; simultaneo

89、usly the method which simulates the software uses in the component parameter the determination. The result indicated that, these measures powerfully increased the accuracy ultrasonic distance measuring.<p&

90、gt;　　4. Measuring and statistics　　In this design uses the transmission characteristic of the ultrasonic wave, auxiliary by AT89C2051 micro-controller, has simulated with Pspice to the hardware major

91、component, no matter from simulation result, looked from the final whole test, all has achieved the satisfactory effect. Table 1 is vertical under　　the conventional condition by the air to the follow

92、ing three medium launch, the demarcation value respectively is 3.0m and 6.0cm, separately surveys the mean value which 50 times obtains.　　Table 1. Measuring and statistics　　5. Co

93、nclusion　　This system finally may maintain the precision ranges in 0.7 to 6 meters, has met the anticipated design requirements and the goal. As a result of the acoustical power rate limit, its maxim

94、um range has been received the limit, if needs to increase the range, may realize through the enlarge acoustical power rate method, this design available carries the ultrasonic rangefinder in the automobile and the freig

95、hter vehicle/ship.etc..　　References　　[1] WANG Jing Zhong, ZHANG Chao Jie. Design of ultrasonic distance measurement instrument with the function of real-time voice broadcast base

96、d on AT89S51. Microcomputer & Its Applications, 2010;04, p. 28-31.　　[2] ZHANG Li-hong, CHEN Bo-jun. A Low-cost System Design for Ultrasonic Distance Measurement Instrument. Control and

97、　　Instruments in Chemical Industry, 2010;37,08, p. 49-52.　　[3] ZHU Shi-hu, HE Pei-zhong, WANG Li-wei. Design of Ultrasonic Tester Based on the AT89S52. Instrumentation</p&

98、gt;　　Technology, 2009; 06, p. 22-24.　　[4] WEI Sui-lin. Development of the digital ultrasonic rangefinder. Electronic Design Engineering, 2009; 10, p. 22-24.　　[5] ZHANG

99、 Tong-huai. Design and Fabrication of Ultrasonic Rangefinder. Instrumentation Technology, 2008; 08, p. 20-22.　　[6] Ye Xiaodong. Design and manufacture of ultrasonic distance measurement instrument. F

100、oreign Electronic Measurement　　Technology, 2008; 11, p.53-56.　　[7] YAN Huai-long. A Device Design of Water Level Measurement Based on Ultrasonic. Mechanical & Electrical Engi

101、neering　　Technology, 2007;03, p. 31-33.　　[8] Liu ChengAn Sun Tao. Development of intelligent ultrasonic meter. Microcomputer Information, 2007;02, p. 101-103.

102、;　　[9] WANG Rui. Research and design of ultrasonic rangefinder based on singlechip. Electronic Instrumentation Customer, 2006;　　13,04, p. 58-60.　　基于微機控制器的超聲波測距設計<p

103、>　　摘要　　本文介紹了基于微機控制器AT89C2051的超聲波測距儀的技術和原理。它從理論和實驗兩個方面研究了超聲波測距儀的性能特點。本研究的主要目的是確定硬件電路原理和軟件設計要點，通過PSPICE的計算機仿真提供了硬件電路的關鍵部分。在本文中，它表明這種類型的超聲波測距儀在實際中是可用的。　　關鍵詞：超聲

104、波測距儀；DDS信號源；微機控制器；　　介紹　　超聲波具有諸多特點，例如指向性強，能量消耗緩慢，在介質中可以傳播較長的傳播距離等。超聲波在兩個不同的介質中傳播時，因為每一種不同的介質都有自己一定的特定的波阻抗，如果這兩種介質之間的波阻抗的差異是非常大的，超聲波就可以從接觸表面發(fā)生發(fā)射，因此，超聲波可以利用該特點進行距

105、離的測量。在常溫下，空氣的波阻抗率是415PA·S / M，水的波阻抗率1.48×106PA·S / M，鋼的波阻抗率是4.5×107PA·S / M。因此，測距儀和位置測量儀或者其他諸如此類的工具等在空氣和鋼之間，或在空氣和水表面之間的距離的測量都可以通過超聲波的這些特點來實現(xiàn)。測距儀的原理就是利用超聲波朝特定的方向發(fā)射出超聲

106、波信號，同時開始計時，超聲波在空氣中傳播，碰到障礙物后會發(fā)生反射，超聲波接收器接收到反射波，并立即停止時間的計數(shù)，根據(jù)計時器上記錄的時間，超聲波的發(fā)射點和障礙物之間的距離就可以被計算出來。在本文中，以AT89C2051單片微機控制器為核心，利用超聲波的上述諸多的特點，設計出的一個成本低，精度高，數(shù)字顯示的可以用于測量距離測距儀。　　二、系統(tǒng)的特點和技術特征的描述<p

107、>　　該測距儀的主要功能是在6m的范圍內進行距離的測量。它的特點是：設計電路簡單，并且體積小；采用微機控制器技術，而且它具有很高的可靠性和測量精度；采用了能降低故障發(fā)生率并且消耗功率和損耗較低的元件，同時以字符液晶數(shù)字的顯示方式顯示距離，便于使用。　　該測距儀主要技術性能有：　　1.測量范圍：0.7~6m ；<

108、;p>　　2.測量誤差：δ≦1.7%；　　3.分辨率：0.01M；　　主要硬件：AT89C2051微控制器，超聲波探測頭（UCM-R40和UCM-T40），字符液晶顯示模塊（TR0802B）。　　三、系統(tǒng)的設計和改進　　圖1系統(tǒng)的結構框圖</

109、b>　　系統(tǒng)的結構框圖如圖1所示。當接通工作電源開始工作時，微機控制器的數(shù)據(jù)處理單元初始化為40 kHz的方波，此時按下PTT按鈕，它將會發(fā)射出正弦波信號；與此同時ER裝置開始同步計時，超聲波經過功率放大器的功率放大之后，由超聲波發(fā)射器發(fā)射出去。當它遇到障礙物時會發(fā)生，反射波發(fā)射回來的時候，由接收器接收到反射信號，然后反射信號經過濾波，放大并且整理波次順序后，發(fā)送到微機控制器的中斷接口，在

110、接收到信號之后微機控制器便停止計時器的計時。此后測距儀便根據(jù)超聲波的發(fā)射和接收到回波信號的時間計算出超聲波發(fā)射點和障礙物點之間的距離；具體的距離計算公式如下：　　式中，S是超聲波發(fā)射和反射之間的探測的范圍，t是計時器上記錄的時間，to是系統(tǒng)延遲時間，v是發(fā)射出去的超聲波在空氣中的傳播速度。　　發(fā)射出去的超聲波在空氣中的速度計算公式如下：

111、;　　式中，v是發(fā)射出去的超聲波在空氣中的傳播速度，T是絕對溫度，vo=331.4m/s。由于超聲波的傳播速度會受溫度和傳播介質的影響，如果測距精度要求很高，它可以通過溫度或經驗補償措施進行一些調整。如果精度不是很高的測距儀，一般可以取340m／s。　?。ㄒ唬┯布O計　　該系統(tǒng)的硬件結構可以分為

112、四個部分：　　1.5V電源；　　2.微機控制器電路的數(shù)據(jù)處理和顯示部分；　　3.超聲波的發(fā)射和接收部分；　　4.放大器單元。　　圖2顯示了基于單片機控制的

113、超聲波測距儀電路圖。　　圖2基于單片機控制的超聲波測距儀電路圖　　該系統(tǒng)的動力裝置采用能夠為微機控制器電路和放大器提供穩(wěn)定的5V直流電壓的三端集成穩(wěn)壓器78L05。微機控制器電路采用由美國愛特梅爾公司生產的低電壓，高性能的CMOS 8單片機AT89C2051，它與一般工業(yè)上標準的MCS-51的指令和引腳能夠兼容，因而是一種功能強大的微機控制器，它也為很多

114、嵌入式控制應用提供了一個高度靈活而且有效的解決方案。在本設計中，它可以產生40kHz的發(fā)射信號，接收超聲波的回波信號，而且可以根據(jù)內部計時器記錄的傳播時間來計算距離，并且控制RT0802B字符液晶顯示模塊顯示出超聲波發(fā)射點和障礙物之間的距離。　　RT0802B是顯示單元。它的核心關鍵AN1用于控制RT0802B的背光；RW1用于調整顯示的對比度；核心關鍵AN2用于控制測距儀的工作開關條件。<

115、;/p>　　超聲波發(fā)射電路由CD4069反相器構成，該電路結構簡單（見示意圖），U1B和U1A，U1E和U1F的連接可以增強輸出電流；在第4引腳，第2引腳和第10引腳，第12引腳處的輸出電壓是相反的。也正是因此原因，發(fā)射器可以獲得最高峰值為9V的正弦交流信號（超聲波發(fā)射器的Q值很高，而只有基波信號會受到影響，諧波信號沒有影響），從而提高發(fā)射功率。　　前置放大器的選擇一

116、般選取的是低功耗集成運算放大器LM324，它是一種可以接收微弱的超聲波信號并且進行放大的超聲波信號接收器。U3B可以輸出2.5V的電壓作為電壓輸出器為其他放大器提供需要的電壓；而考慮到超聲波接收器的輸出阻抗高，U3D設計出來作為電壓輸出器來提高放大器電路的輸入阻抗；U3A是用來組成有源帶通濾波器的，它的中心頻率為40kHz，增益為20，它可以過濾各種無用的信號；U3C是由復合材料構成的反相放大器，它的增益為10。由此超聲波接收器的總增益

117、為200。LM393低功耗損耗的雙回雙極比較器可以構成回波整形單元，它可以將所接收的信號進行整理整形，并且向微機控制器輸出方波信號。　?。ǘ┯布抡?lt;/b>　　利用軟件仿真的方法，可以用來設計電路，并且有利于電路的優(yōu)化設計與參數(shù)的最終調試。在完成最初的集成電路設計圖之后，硬件電路的調試工作主要集中在有源帶通濾波器部分。為了

118、調試的方便，首先在PSPICE上設計出這個電路并且進行模擬，以確定具體的參數(shù)要求，不但可以提高系統(tǒng)的性能，還大大簡化了調試工作。圖3是仿真電路圖，圖4幅頻特性的仿真結果，從圖中可以看出，通過選擇合適的組件，該聲波放大器的參數(shù)已經非常理想化，它的中心頻率正是超聲波在工作時的頻率40kHz。　　圖3仿真電路圖　　圖4幅頻

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外文翻譯--基于微機控制器的超聲波測距設計

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