外文翻譯--超聲波測(cè)距系統(tǒng)

1、<p><b>　　附 錄2</b></p><p>　　This article described the three directions (before, left, right) ultrasonic ranging system is to understand the front of the robot, left and right environment to

2、 provide a movement away from the information. (Similar to GPS Positioning System) </p><p>　　A principle of ultrasonic distance measurement </p><p>　　1, the principle of piezoelectric ultrasonic

3、 generator </p><p>　　Piezoelectric ultrasonic generator is the use of piezoelectric crystal resonators to work. Ultrasonic generator, the internal structure as shown in Figure 1, it has two piezoelectric chi

4、p 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 pl

5、ate vibration resonance, ultrasound is generated. Conversely, if the two are not inter-electrode v</p><p>　　2, the principle of ultrasonic distance measurement </p><p>　　Ultrasonic transmitter i

6、n 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, obstacles on his way to return immediately, the ultrasonic reflected wave received

7、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),

8、 that is: s = 340t / 2 </p><p>　　Ultrasonic Ranging System for the Second Circuit Design </p><p>　　System is characterized by single-chip microcomputer to control the use of ultrasonic transmitt

9、er 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 2. Draw only

10、 the front range of the circuit wiring diagram, left and right in front of Ranging Ranging circuits and the same circuit, it is omitted. </p><p>　　1,40 kHz ultrasonic pulse generated with the launch </p&g

11、t;<p>　　Ranging system using the 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

12、 generate. </p><p>　　puzel: mov 14h, # 12h; ultrasonic firing continued 200ms </p><p>　　here: cpl p1.0; output 40kHz square wave </p><p><b>　　nop; </b></p><p&

13、gt;<b>　　nop; </b></p><p><b>　　nop; </b></p><p>　　djnz 14h, here; </p><p><b>　　ret </b></p><p>　　Ranging in front of single-chip term

14、ination 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

15、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.

16、 </p><p>　　2, reception and processing of ultrasonic </p><p>　　Used to receive the first launch of the first pair UCM40R, the ultrasonic pulse modulation signal into an alternating voltage, the

17、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 targ

18、et 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 </p><p>　　Ranging in front of single-chip termination circ

19、uit output port INT0 interrupt the highest priority, right or left location of the output circuit with output gate IC3A access INT1 port single-chip, while single-chip P1.3 and P1. 4 received input IC3A, interrupted by t

20、he process to identify the source of inquiry to deal with, interrupt priority level for the first left right after. Part of the source code is as follows: </p><p>　　receive1: push psw </p><p>&l

21、t;b>　　push acc </b></p><p>　　clr ex1; related external interrupt 1 </p><p>　　jnb p1.1, right; P1.1 pin to 0, ranging from right to interrupt service routine circuit </p><p>

22、;　　jnb p1.2, left; P1.2 pin to 0, to the left ranging circuit interrupt service routine </p><p>　　return: SETB EX1; open external interrupt 1 </p><p><b>　　pop? acc </b></p>&l

23、t;p><b>　　pop? psw </b></p><p><b>　　reti </b></p><p>　　right: ...?; right location entrance circuit interrupt service routine </p><p>　　? Ajmp? Return <

24、/p><p>　　left: ...; left Ranging entrance circuit interrupt service routine </p><p>　　? Ajmp? Return </p><p>　　4, the calculation of ultrasonic propagation time </p><p>　　

25、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

26、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 implem

27、entation of the external interrupt service subroutine, read </p><p>　　RECEIVE0: PUSH PSW </p><p><b>　　PUSH ACC </b></p><p>　　CLR EX0; related external interrupt 0 </p

28、><p>　　? MOV R7, TH0; read the time value </p><p>　　MOV R6, TL0? </p><p><b>　　CLR C </b></p><p>　　MOV A, R6 </p><p>　　SUBB A, # 0BBH; calculate th

29、e time difference </p><p>　　MOV 31H, A; storage results </p><p>　　MOV A, R7 </p><p>　　SUBB A, # 3CH </p><p>　　MOV 30H, A? </p><p>　　SETB EX0; open external

30、 interrupt 0 </p><p><b>　　POP ACC? </b></p><p><b>　　POP PSW </b></p><p><b>　　RETI </b></p><p>　　Fourth, the ultrasonic ranging syste

31、m software design </p><p>　　Software is divided into two parts, the main program and interrupt service routine, shown in Figure 3 (a) (b) (c) below. Completion of the work of the main program is initialized,

32、 each sequence of ultrasonic transmitting and receiving control. </p><p>　　Interrupt service routines from time to time to complete three of the rotation direction of ultrasonic launch, the main external int

33、errupt service subroutine to read the value of completion time, distance calculation, the results of the output and so on. </p><p>　　V. CONCLUSIONS </p><p>　　Required measuring range of 30cm ~ 2

34、00cm 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 si

35、mple, reliable, small features such as measurement error. Therefore, it can be used not only for mobile robot can be used in other detection systems. </p><p>　　Thoughts: As for why the receiver do not have t

36、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 ul

37、trasonic sensors frequency</p><p>　　本文所介紹的三方向（前、左、右）超聲波測(cè)距系統(tǒng)，就是為機(jī)器人了解其前方、左側(cè)和右側(cè)的環(huán)境而提供一個(gè)運(yùn)動(dòng)距離信息。（類似GPS定位系統(tǒng)） </p><p>　　一 超聲波測(cè)距原理 </p><p>　　1、壓電式超聲波發(fā)生器原理</p><p>　　壓電式超聲波發(fā)生器實(shí)

38、際上是利用壓電晶體的諧振來(lái)工作的。超聲波發(fā)生器內(nèi)部結(jié)構(gòu)如圖1所示，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(hào)，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，如果兩電極間未外加電壓，當(dāng)共振板接收到超聲波 時(shí)，將壓迫壓電晶片作振動(dòng)，將機(jī)械能轉(zhuǎn)換為電信號(hào)，這時(shí)它就成為超聲波接收器了。</p><p><b>　　2、超聲波測(cè)距原理</b>

39、</p><p>　　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(kāi)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(lái)，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)距障礙物的距離(s)，即：s=340t/2</p><p>　　二 超聲波測(cè)距系統(tǒng)的電路設(shè)計(jì)</p><p>　　系統(tǒng)

40、的特點(diǎn)是利用單片機(jī)控制超聲波的發(fā)射和對(duì)超聲波自發(fā)射至接收往返時(shí)間的計(jì)時(shí)，單片機(jī)選用8751，經(jīng)濟(jì)易用，且片內(nèi)有4K的ROM，便于編程。電路原理圖如圖2所示。其中只畫出前方測(cè)距電路的接線圖，左側(cè)和右側(cè)測(cè)距電路與前方測(cè)距電路相同，故省略之。</p><p>　　1、40kHz 脈沖的產(chǎn)生與超聲波發(fā)射</p><p>　　測(cè)距系統(tǒng)中的超聲波傳感器采用UCM40的壓電陶瓷傳感器，它的工作電壓是40

41、kHz的脈沖信號(hào)，這由單片機(jī)執(zhí)行下面程序來(lái)產(chǎn)生。</p><p>　　puzel： mov 14h, #12h；超聲波發(fā)射持續(xù)200ms</p><p>　　here： cpl p1.0 ； 輸出40kHz方波</p><p><b>　　nop ；</b></p><p><b>　　no

42、p ；</b></p><p><b>　　nop ；</b></p><p>　　djnz 14h，here；</p><p><b>　　ret</b></p><p>　　前方測(cè)距電路的輸入端接單片機(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(hào)

43、，經(jīng)過(guò)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)和左側(cè)測(cè) 距電路的輸入端分別接P1.1和P1.2端口，工作原理與前方測(cè)距電路相同。</p><p>　　2、超聲波的接收與處理</p><p>　　接收頭采用與發(fā)射頭配對(duì)的UCM40R，將超聲波調(diào)制脈沖變?yōu)榻蛔冸妷盒盘?hào)，經(jīng)運(yùn)算放大器IC1A和IC1B兩極放大后加至IC2。IC2是帶有鎖

44、定環(huán)的音頻譯碼集成塊LM567，內(nèi)部的壓控振蕩器的中心頻率f0=1/1.1R8C3，電容C4決定其鎖定帶寬。調(diào)節(jié)R8在發(fā)射的載頻上，則LM567 輸入信號(hào)大于25mV，輸出端8腳由高電平躍變?yōu)榈碗娖?，作為中斷?qǐng)求信號(hào)，送至單片機(jī)處理.</p><p>　　前方測(cè)距電路的輸出端接單片機(jī)INT0端口，中斷優(yōu)先級(jí)最高，左、右測(cè)距電路的輸出通過(guò)與門IC3A的輸出接單片機(jī)INT1端口，同時(shí)單片機(jī)P1.3和P1.4接到IC3

45、A的輸入端，中斷源的識(shí)別由程序查詢來(lái)處理，中斷優(yōu)先級(jí)為先右后左。部分源程序如下：</p><p>　　receive1：push psw</p><p><b>　　push acc</b></p><p>　　clr ex1 ； 關(guān)外部中斷1</p><p>　　jnb p1.1, right

46、； P1.1引腳為0,轉(zhuǎn)至右測(cè)距電路中斷服務(wù)程序</p><p>　　jnb p1.2, left ； P1.2引腳為0,轉(zhuǎn)至左測(cè)距電路中斷服務(wù)程序</p><p>　　return： SETB EX1； 開(kāi)外部中斷1</p><p><b>　　pop? acc</b></p><p><

47、;b>　　pop? psw</b></p><p><b>　　reti</b></p><p>　　right： ...? ； 右測(cè)距電路中斷服務(wù)程序入口</p><p>　　? ajmp? return</p><p>　　left： ..

48、. ； 左測(cè)距電路中斷服務(wù)程序入口</p><p>　　? ajmp? return</p><p>　　4、計(jì)算超聲波傳播時(shí)間</p><p>　　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)間和收到反射波的時(shí)間。當(dāng)收到超聲波反射波時(shí)，接收電路 輸出端產(chǎn)生一個(gè)負(fù)跳變，在INT0或I

49、NT1端產(chǎn)生一個(gè)中斷請(qǐng)求信號(hào)，單片機(jī)響應(yīng)外部中斷請(qǐng)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：</p><p>　　RECEIVE0： PUSH PSW</p><p><b>　　PUSH ACC</b></p><p>　　CLR EX0 ； 關(guān)外部中斷0</p><p>

50、;　　? MOV R7, TH0 ； 讀取時(shí)間值</p><p>　　MOV R6, TL0?</p><p><b>　　CLR C</b></p><p><b>　　MOV A, R6</b></p><p>　　SUBB A, #0BBH； 計(jì)算時(shí)間差</p><p

51、>　　MOV 31H, A ； 存儲(chǔ)結(jié)果</p><p><b>　　MOV A, R7</b></p><p>　　SUBB A, #3CH</p><p>　　MOV 30H, A?</p><p>　　SETB EX0 ； 開(kāi)外部中斷0</p><p&g

52、t;<b>　　POP ACC?</b></p><p><b>　　POP PSW</b></p><p><b>　　RETI</b></p><p>　　四、超聲波測(cè)距系統(tǒng)的軟件設(shè)計(jì)</p><p>　　軟件分為兩部分，主程序和中斷服務(wù)程序，如圖3（a）（b）(c) 所示

53、。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。</p><p>　　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。</p><p><b>　　五、結(jié)論</b></p><p>　　對(duì)所要求測(cè)量范圍30cm~200cm內(nèi)的平面物體做了多次測(cè)量發(fā)現(xiàn)，其最大誤差為0.5c