超声测距相关毕业设计外文资料翻译
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摘要:超声测距系统技校在工业场车辆导航水声工程等领域都具有了广泛的应用价值,目前已应用于物理测量,机器人自动导航以及空气中与水下的目标探测、识别定位等场合,因此,深入研究超声的探测理论和方法具有重要的实践意义,为了进一步提高测量的精确度,满足工程人员对测量精度测距量程和测距仪使用的要求,本文研制了一套基于单片机的使拱式超声测距系统。
关键词:超声波测距仪单片机1、前言随着科技的发展,人们生活水平的提高,城市发展建设加快,城市给排水系统也有较大发展,其状况不断改善,但是,由于历史原因合成时间性的许多不可预见因素,城市给排水系统,特别是排水系统往往落后于城市建设,因此,经常出现开挖已经建设好的建筑设施来改造排水系统的现象。
城市污水给人们带来的困扰,因此箱的排污疏通对大城市给排水系统污水理,人们生活舒适显得非常重要。
而设计研制箱涵排水疏通移动机器人的自动控制系统,保证机器人在箱涵中自由排污疏通,是箱涵排水系统疏通机器人的设计研制的核心部分,控制系统核心部分就是超声波测仪的研制。
因此,设计好的超声波测距仪就显得非常重要了。
1.1课题背景随着经济的发展与汽车科学技术的进步,公路交通呈现出行驶高速化、车流密集化和驾驶员非职业化的趋势。
同时,随着汽车工业的飞速发展,汽车的产量和保有量都在急剧增加。
但公路发展、交通管理却相对落后,导致了交通事故与日剧增,城市里尤其突出。
智能交通系统ITS是目前世界上交通运输科学技术的前沿技术,它在充分发挥现有基础设施的潜力,提高运输效率,保障交通安全,缓解交通赌塞,改善城市环境等方面的卓越效能,已得到各国政府的广泛关注。
中国政府也高度重视智能交通系统的研究开发与推广应用。
汽车防撞系统作为ITS 发展的一个基础,它的成功与否对整个系统有着很大的作用。
从传统上说,汽车的安全可以分为两个主要研究方向:一是主动式安全技术,即防止事故的发生,该种方式是目前汽车安全研究的最终目的;二是被动式安全技术,即事故发生后的乘员保护。
学科分类号0805本科毕业设计题目(中文):体重及超声波远距测高仪-----体重检测(英文):Weight and ultrasonic distance altimeter-----weight detection姓名学号院(系)工程与设计学院专业、年级指导教师兆仁二〇一四年五月师大学本科毕业设计诚信声明本人重声明:所呈交的本科毕业设计,是本人在指导老师的指导下,独立进行研究工作所取得的成果,成果不存在知识产权争议,除设计中已经注明引用的容外,本设计不含任何其他个人或集体已经发表或撰写过的作品成果。
对本设计的研究做出重要贡献的个人和集体均已在文中以明确方式标明。
本人完全意识到本声明的法律结果由本人承担。
本科毕业设计作者签名:二〇一四年五月二十日师大学本科毕业设计任务书XX师大学工程与设计学院指导教师指导毕业设计情况登记表师大学本科毕业设计评审表优秀,80—89分记为良好,70—79分记为中等,60—69分记为及格,60分以下记为不及格。
若译文成绩为零,则不计总成绩,评定等级记为不及格。
师大学本科毕业设计答辩记录表目录摘要1Abstract21 引言31.1 选题背景及目的31.2 总体方案设计与论证41.2.1 设计任务41.2.2 设计容41.2.3 方案论证与选择52 硬件电路设计62.1 主控电路62.2 超声波测高模块电路82.2.1 超声波传感器及其测高原理82.2.2 超声波传感器电气参数及其时序图92.3 压力传感器称重模块112.3.1 压力传感器112.3.2 称重AD转换芯片132.3.3 称重部分AD转换基本原理152.3.4 称重传感器重量标定162.4 LCD1602液晶显示模块172.4.1 LCD1602介绍172.4.2 LCD1602主要技术参数及其时序图193 系统软件设计213.1 单片机初始化程序设计213.2 超声波测高模块程序设计223.3 测体重程序设计243.4 液晶显示模块程序设计24 结论26参考文献27附录28致58体重及超声波远距离测高仪-----体重检测专业:电子信息工程年级:2010级:练摘要在如今体检过程中,身高和体重是必要的测量部分。
附录A 英文原文ULTASONIC RANGING IN AIRG. E. Rudashevski and A. A. GorbatovOne of the most important problems in instrumentation technology is the remote,contactless measurement of distances in the order of 0.2 to 10 m in air.Such a problem occurs,for instance,when measuring the relativethre edimensional position of separate machine members or structural units.Interesting possibilities for its solution are opened up by utilizing ultrasonic vibrations as an information carrier.The physical properties of air,in which the measurements are made,permit vibrations to be employed at frequencies up to 500 kHz for distances up to 0.5 m between a member and the transducer,or up to 60 kHz when ranging on obstacles located at distances up to 10 m.The problem of measuring distances in air is somewhat different from other problems in the a -pplication of ultrasound.Although the possibility of using acoustic ranging for this purpose has been known for a long time,and at first glance appears very simple,nevertheless at the present time there are only a small number of developments using this method that are suitable for practical purposes.The main difficulty here is in providing a reliable acoustic three-dimensional contact with the test object during severe changes in the air's characteristic.Practically all acoustic arrangements presently known for checking distances use a method of measuring the propagation time for certain information samples from the radiator to the reflecting member and back.The unmodulated acoustic(ultrasonic)vibrations radiated by a transducer are not in themselves a source of information.In order to transmit some informational communication that can then be selected at the receiving end after reflection from the test member,the radiated vibrations must be modulated.In this case the ultrasonic vibrations are the carrier of the information which lies in the modulation signal,i.e.,they are the means for establishing the spatial contact between the measuring instrument and the object being measured.This conclusion,however,does not mean that the analysis and selection of parameters for the carrier vibrations is of minor importance.On the contrary,the frequency of the carrier vibrations is linked in a very close manner with the coding method for the informational communication,with the passband of the receiving and radiating elements in the apparatus,with the spatial characteristics of the ultrasonic communication channel,and with the measuring accuracy.Let us dwell on the questions of general importance for ultrasonic ranging in air,namely:on the choice ofa carrier frequency and the amount of acoustic power received.An analysis shows that with conical directivity diagrams for the radiator and receiver,and assuming thatthe distance between radiator and receiver is substantially smaller than the distance to the obstacle,theamount of acoustic power arriving at the receiving area Pr for the case of reflection from an ideal planesurface located at right angles to the acoustic axis of the transducer comes towhere Prad is the amount of acoustic power radiated,B is the absorption coefficient for a plane wave inthe medium,L is the distance between the electroacoustic transducer and the test me -mber,d is the diameterof the radiator(receiver),assuming they are equal,and c~is the angle of the directivity diagram for theelectroacoustic transducer in the radiator.Both in Eq.(1)and below,the absorption coefficient is dependent on the amplitude and not on theintensity as in some works[1],and therefore we think it necessary to stress this difference.In the various problems of sound ranging on the test members of machines and structures,therelationship between the signal attenuations due to the absorption of a planewave and due to thegeometrical properties of the sound beam are,as a rule,quite different.It must be pointed out that the choiceof the geometrical parameters for the beam in specific practical cases is dictated by the shape of thereflecting surface and its spatial distortion relative to some average position.Let us consider in more detail the relationship betweenthe geometric and the power parameters ofacoustic beams for the most common cases of ranging on plane and cylindrical structural members.It is well known that the directional characteristic W of a circular piston vibrating in an infinite baffle is afunction of the ratio of the piston's diameter to the wavelength d/λ as found from the following expression:(2)where Jl is a Bessel function of the first order and α is the angle between a normal to the piston and aline projected from the center of the piston to the point of observation(radiation).From Eq.(2)it is readily found that a t w o-t o-o n e reduction in the sensitivity of a radiator with respectto sound pressure will occur at the angle(3)For angles α≤20.Eq.(3)can be simplified to(4) where c is the velocity of sound in the medimaa and f is the frequency of the radiated vibrations.It follows from Eq.(4)that when radiating into air where c=330 m/s e c,the necessary diameter of the radiator for a spedfied angle of the directivity diagram at the 0.5 level of pressure taken with respect to the fdc 76.05.0≈αaxis can befound to be(5)where disincm,f is in kHz,and α is in degrees of angle.Curves are shown in Fig.1 plotted from Eq.(5)for six angles of a radiator's directivity diagram.The directivity diagrm needed for a radiator is dictated by the maximum distance to be measured and bythe spatial disposition of the test member relative to the other structural members.In order to avoid theincidence of signals reflected from adjacent members onto the acoustic receiver,it is necessary to provide asmall angle of divergence for the sound beam and,as far as possible,a small-diameter radiator.These tworequirements are mutually inconsistent since for a given radiation frequency a reduction of the beam'sdivergence angle requires an increased radiator diameter.In fact,the diameter of the"sonicated"spot is controlled by two variables,namely:the diameter of theradiator and the divergence angle of the sound beam.In the general case the minimum diameter ofthe"sonicated"spot Dmin on a plane surface normally disposed to the radiator's axis is given by(6)where L is the least distance to the test surface. The specified value of Dmin corresponds to a radiator with a diameter(7)As seen from Eqs.(,6)and(7),the minimum diameter of the"sonieated"spot at the maximum requireddistancecannot be less than two radiator diameters.Naturally,with shorter distances to the obstacle the sizeof the"sonicated" surface is less.Let us consider the case of sound ranging on a cylindrically shaped object of radius R.The problem is to measure the distance from the electroacoustic transducer to the side surface of the cylinderwith its various possible displacements along the X and Y axes.The necessary angleαof the radiator'sdirectivity diagram is given in this case by the expression(8) whereα is the value of the angle for the directivity diagram,Ymax is the maximum displacement of the cylinder's center from the acoustic axis,and Lmin is the minimum distance from the center of theelectroacoustic transducer to the reflecting surface measured along the straight line connecting the center ofthe m e m b e r with the center of the transducer.It is clear that when measuring distance,the"running"time of the information signal is controlled by thefd α1400≈fcL d 5.1=fcLD 6min =min maxarcsinL R y +≥αlength of the path in a direction normal to the cylinder's surface,or in other words,the measure distance isalways the shortest one.This statement is correct for all cases of specular reflection of the vibrations from thetest surface.The simultaneous solution of Eqs.(2)and(8)when W=0.5 leads to the following expression:(9) In the particular case where the sound ranging takes place in air having c=330 m/sec,and on theasstunption that L min <<R,the necessary d i a m e t e r of a unidirectional piston radiator d can be found fromthe fomula (10) where d is in cm and f is in kHz. Curves are shown in Fig.2 for determining the necessary diameter of the radiator as a function of theratio of the cylinder's radius to the maximum displacement from the axis for four radiation frequencies.Alsoshown in this figure is the directivity diagram angle as a function of R and Y rnax for four ratios of m i n i m u mdistance to radius.The ultrasonic absorption in air is the second factor in determining the resolution of ultrasonic rangingdevices and their range of action.The results of physical investigations concerning the measurement ofultrasonic vibrations air are given in[1-3].Up until now there has been no unambiguous explanation of thediscrepancy between the theoretical and expe -rimental absorption results for ultrasonic vibrations inair.Thus,for frequencies in the order of 50 to 60 kHz at a temperature of+25oC and a relative humidity of37%the energy absorption coefficient for a plane wave is about 2.5dB/m while the theoretical value is 0.3 dB/m.The absorption coefficient B as a function of frequency for a temperature of+25o Cand a humidity of37%according to the data in[2]can be described by Table 1.The absorption coefficient depends on the relative humidity.Thus,for frequencies in the order of 10 to20kHz the highest value of the absorption coefficient occurs at 20%humidity[3],and at 40%humidity theabsorption is reduced by about two to one.For frequencies in the order of 60 kHz the maximum absorptionoccurs at 30.7o humidity,dropping when it is increased to 98% or lowered to 10%by a factor of approximatelyfour to one.The air temperature also has an appreciable effect on the ultrasonic absorption[1].When thetemperature of the medium is increased from+10 to+30,the absorption for frequencies between 30 and 50kHz increases by about three to one.Taking all the factors noted above into account we arrive at the following approximate values for theabsorption coefficient:at a frequency of 60 kHz /3min =0.15 m -1 and~max=0.5-1;at a frequency of 200 ()maxmin 76.0y L R d +=λmax25fy R d ≈kHz/~min=0.6 m -1 and B max =2 m -1.(11)The values for the minimum~min and rnaxil-num~max"transmittance"coefficients were obtained in thea bsence of aerosols and rain.Their difference is the result of the possible variations in temperature over therange from -3 0 to+50~and in relative hmnidity over the range from 10 to 98%.The overall value ofthe"transmittance"is obtained by multiplying the values of g and 0 for given values of L,f,and d.L I T E R A T U R E C I T E DMoscow(1957).Moscow(1960).附录B 中文翻译在空气中超声测距G. E. Rudashevski and A. A. Gorbatov在仪器技术中远程是最重要的一个问题。
=======大学本科生毕业设计外文文献及中文翻译文献题目: ULTRASONIC RANGING SYSTEM 文献出处: United States Patent译文题目:超声波测距系统学生:指导教师:专业班级:自动化11-4学号: 110601140416电气信息工程学院2014年5月1日超声波测距系统摘要超声波测距系统,是指选择性地激励一个变压器,使之产生换能器驱动信号。
超声换能器发射的超声波脉冲用于响应驱动信号然后接收到一个在超声波信号发出之后的回波信号。
分路开关接在变压器的绕组上,当超声波信号的传输在允许的近距离范围内达到一个稳定的等级,分路开关选择性的闭合来阻止蜂鸣器报警。
第1章发明背景像在宝丽来相机中应用的可用范围测试系统,它们都是准确而且可靠的,但都不适用于近距离测距,举个例子,2到3英寸的距离内就不适用,所以他们在9英寸甚至更远的距离测距是可靠的。
它们可以应用在很多的应用程序中,但不适用于可移动机器人领域内。
机器人通常必须通过门口只有两三英寸的间隙,如果当可移动机器人被操作于避障模式下通过狭小空间,可能机器人的规避路径过于狭窄,此外,规避动作应该使偏指定的路径距离最小化。
近距离测距不用于超声波系统的一个原因是,近距离输出脉冲输出太长以至于它重叠在回波脉冲上,即使输出脉冲缩短,输出脉冲仍然重叠回波脉冲,因为声音紧跟着输出脉冲。
备中产生的回波信号脉冲的范围为100毫伏,但设置传感器响应所必需的电路回声脉冲是大约150伏到300伏之间。
因此即使是最小的声波也会盖过回声信号。
事实上,dual-diode钳位电路用于将150伏降低到二极管的击穿电压,即0.7伏特。
但是这700毫伏足以盖过100毫伏的回波信号。
目前系统需要50毫秒将300伏特的峰值发射电压降到0.7伏特,且额外需要500到600毫秒的时间将它稳定在1毫伏范围。
第2章发明总结本发明可以提供一种改进的超声波测距系统。
本发明也可以提供一个改进的多通道超声波测距系统。
超声波测距摘要:本演示处理了测量距离的超声波传感器在当前环境中的准确性。
作为一个测量传感器的选择SFR08型配备了允许寻址的I ²C 通信接口。
这一事实使得创建传感器阵列变得简单。
控制和可视化系统是基于PC PC。
NI USB 8451是作为通信卡使用的。
验证测量的目标是确定实际的传感器精度,特别是当测量较长的距离。
当评估传感器的精度时,不包括在所测量的数据的温度补偿。
关键词:超声波传感器,I ²C 通信接口,虚拟仪器1 1 简介简介超声波传感器通常用于自动化的任务来测量距离,位置变化,电平测量,如存在检测器或在特殊应用中,例如,当测量透明材料的纯度。
它们是基于测量超声波的传播时间的原则。
这一原则确保可靠的检测是独立的颜色渲染的对象或其表面的设计和类型。
它可以可靠地检测甚至液体,散装材料,透明物体,玻璃等材料。
他们使用的另一个参数是他们在侵略性的环境中使用,不是非常敏感的污垢和测量距离的可能性。
超声波传感器在许多机械设计中被制造。
对于实验室用途,用于发射器和接收器单独或在一个单一的简单的住房,对于工业用途,往往建造坚固的金属外壳。
有些类型允许您使用电位计或数字来调整灵敏度。
此外,输出可以在统一的版本中或直接以数字形式的模拟信号直接中。
就传感器来说,可以通过通信接口连接到PC ,它是可以设置所有传感器的工作范围和测量距离的详细参数。
2 2 超声测量超声测量超声对环境中的声音具有相似的传播特性。
这是机械振动的粒子环境。
超声波可以在气体、液体和固体中传播。
对于超声波通常被认为是一个频率高于20千赫的声音。
千赫的声音。
根据超声波的用途可以分为两类: 主动超声:当应用表现出物理或化学效应。
生成的输出达到更高的值。
超声波用于清洁,焊接,钻孔等。
被动超声;输出是在低得多(通常是小)值产生的对比度。
他的主要应用领域是测量距离,检测材料的缺陷和材料的厚度,测量液体和气体的流量,以及医疗保健的诊断。
Ultrasonic distance and velocity measurement using a pair of LPM signals for cross-correlation method:Improvement of Doppler-shift compensation and examination of Doppler velocity estimation超声波距离和速度利用互相关方法对LPM信号测量:多普勒频移补偿和多普勒速度估计检测的改进数据来源Elsevier Journal Elsevier期刊刊物名Ultrasonics, 2012, Vol.52 (7), pp.873-879 超声波,2012,卷(7),pp.873-879 作者Shinnosuke Hirata, Minoru Kuribayashi Kurosawashinnosuke平田,稔栗林黑泽明单位机械工程与智能系统1,信息工程学院,电子通信,1-5-1 chofugaoka e4-329,,,布,东京182-8585大学,日本信息处理系,跨学科研究生科学与工程学院,东京工业大学,4259首席人事官g2-32,长津田,绿区,横滨,神奈川226-8502,日本AbstractReal-time distance measurement of a moving object with high accuracy and high resolution using an ultrasonic wave is difficult due to the influence of the Doppler effect or the limit of the calculation cost of signal processing. An over-sampling signal processing method using a pair of LPM signals has been proposed for ultrasonic distance and velocity measurement of moving objects with high accuracy and high resolution. The proposed method consists of cross correlation by single-bit signal processing, high-resolution Doppler velocity estimation with wide measurement range and low-calculation-cost Doppler-shift compensation. The over-sampling cross-correlation function is obtained from cross correlation by single-bit signal processing with low calculation cost. The Doppler velocity and distance of the object are determined from the peak interval and peak form in the cross-correlation function by the proposed method of Doppler velocity estimation and Doppler-shift compensation. In this paper, the proposed method of Doppler-shift compensation is improved. Accuracy of the determined distance was improved from approximately within ±140 μm in the previous method to approximately within ±10μm in computer simulations. Then, the proposed method of Doppler velocity estimation is evaluated. In computer simulations, accuracy of the determined Doppler velocity and摘要实时测量移动物体的高精度和高分辨率超声波存在的多普勒效应或信号处理的计算成本的限制的影响。
超声波测距仪毕业论文中文摘要电子测距仪要求测量范围在50cm~500cm,测量精度1cm,测量时与被测物体无直接接触,能够清晰稳定地显示测量结果。
由于超声波指向性强,能量消耗缓慢,在介质中传播的距离较远,因而超声波经常用于距离的测量。
如测距仪和物位测量仪等都可以通过超声波来实现。
超声波测距器,可以应用于汽车倒车、建筑施工工地以及一些工业现场的位置监控,也可用于液位、井深、管道长度的测量等场合。
利用超声波检测往往比较迅速、方便、计算简单、易于做到实时控制,并且在测量精度方面能达到工业实用的要求。
因此在移动机器人的研制上也得到了广泛的应用。
我的超声波测距仪设计采用74hc04反相器和CX20106搭接电路实现了超声波的发射与接收。
采用AT89C51单片机为该测距仪的控制核心,此设计易于调试,成本低廉,具有很强的实用价值和良好的市场前景。
关键词:超声波传感器,单片机,测距仪ABSTRACTElectronic distance measurement instrument for measurement in the range of 20cm-2.5m, precision 1cm, with the measurement of the measured object without direct contact, can clearly demonstrate the stability of the measurement results. Because of the strong point of ultrasonic energy consumption, slow, medium of communication in the longer distance, which are often used for ultrasonic distance measurement. Such as the range finder and level measurement and so on can be achieved by ultrasound. Ultrasonic ranging, can be applied to car parking, construction sites and some industrial site location monitoring, and can also be used for liquid level, depth, pipe length measurement occasions. Use of ultrasonic testing is often more rapid, convenient, simple, easy to achieve real-time control, and measurement accuracy can meet the practical requirements of industry. In the mobile robot has been developed on a wide range of applications. My car anti-collision anti-theft alarm system design using 74hc04inverter and CX20106lap circuit to realize the ultrasonic transmitter and receiver. Using AT89C51 SCM as the control core of the range finder, this design easy debugging, low cost, has the very strong practical value and good market prospects. Key words: ultrasonic sensor, single chip microcomputer, range finder,目录第一章绪论 .............................................................................................................................................. - 1 - 1.1 设计项目概述 ..................................................................................................................................... - 1 - 1.2 设计要求 ............................................................................................................................................. - 1 - 1.3 超声波测距原理 ................................................................................................................................. - 1 - 第二章超声波测距仪的内容及意义 ...................................................................................................... - 3 - 2.1 超声波测距仪的意义 ......................................................................................................................... - 3 - 2.2超声波测距仪的内容 .......................................................................................................................... - 3 - 第三章系统方案选择 .............................................................................................................................. - 3 - 3.1 方案一 ................................................................................................................................................. - 4 - 3.2 方案二 ................................................................................................................................................. - 4 - 3.3 方案确定 ............................................................................................................................................. - 4 - 第四章系统硬件电路设计 ...................................................................................................................... - 4 - 4.1单片机模块 .......................................................................................................................................... - 4 -4.1.1 AT89C51标准功能 .................................................................................................................. - 5 -4.1.2管脚说明................................................................................................................................... - 6 - 4.2超声波谐振频率调理电路模块 .......................................................................................................... - 7 - 4.3超声波回路接收处理电路模块 .......................................................................................................... - 8 - 4.4数码管显示模块 .................................................................................................................................. - 8 - 第五章系统软件程序设计 ...................................................................................................................... - 9 -5.1 超声波测距程序设计 ......................................................................................................................... - 9 - 5.2 超声波测距流程图 ........................................................................................................................... - 10 - 第六章系统软硬件调试 ........................................................................................................................ - 10 -6.1 硬件调试 ........................................................................................................................................... - 10 - 6.2 软件调试 ........................................................................................................................................... - 11 - 6.3 测试结果 ........................................................................................................................................... - 11 - 第七章调试中遇到的问题 .................................................................................................................... - 11 -7.1 发射接收时间对测量精度的影响分析 ........................................................................................... - 11 - 7.2 当地声速对测量精度的影响分析 ................................................................................................... - 12 - 总结 ........................................................................................................................................................ - 13 - 参考文献 .................................................................................................................................................. - 14 -附录A ....................................................................................................................................................... - 0 - 附录B ........................................................................................................................................................ - 0 - 致谢 ........................................................................................................................................................ - 6 -第一章绪论声波在其传播介质中被定义为纵波。
毕业设计论文外文文献翻译超声波测距中英文对照The Circuit Design of UltrasonicRanging System超声波测距系统的电路设计Ultrasonic Distance Meter超声波测距仪姓名:专业: 测控技术与仪器学号: 2007071071指导教师姓名,职称,:The Circuit Design of Ultrasonic Ranging SystemThis article described the three directions (before, left, right) ultrasonic ranging system is to understand the front of the robot, left and right environment to provide a movement away from the information. (Similar to GPS Positioning System)A principle of ultrasonic distance measurement1, the principle of piezoelectric ultrasonic generatorPiezoelectric ultrasonic generator is the use of piezoelectriccrystal resonators to work. Ultrasonic generator, the internal structure as shown in Figure 1, 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 vibrationresonance, ultrasound is generated. Conversely, if the two are notinter-electrode voltage, when the board received ultrasonic resonance,it will be for vibration suppression of piezoelectric chip, the mechanical 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, 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), that is: s = 340t / 2 Ultrasonic Ranging System for the Second Circuit 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 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 circuits and the same circuit, it is omitted.1,40 kHz ultrasonic pulse generated with the launchRanging system using the ultrasonic sensor of piezoelectric ceramic sensors UCM40, its operating voltage of the pulse signal is 40kHz, whichby the single-chip implementation of the following procedures to generate.puzel: mov 14h, # 12h; ultrasonic firing continued 200mshere: cpl p1.0; output 40kHz square wavenop;nop;nop;djnz 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 a40kHz pulse 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.2, reception and processing of ultrasonicUsed 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-controlledoscillator 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 outputfrom 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 INT0 interrupt the highest priority, right or left location of the output circuit with output gate IC3A access INT1 port single-chip, whilesingle-chip P1.3 and P1. 4 received input IC3A, interrupted by the process to identify the source of inquiry to deal with, interruptpriority level for the first left right after. Part of the source codeis as follows:receive1: push pswpush accclr ex1; related external interrupt 1jnb p1.1, right; P1.1 pin to 0, ranging from right to interrupt service routine circuitjnb p1.2, left; P1.2 pin to 0, to the left ranging circuit interrupt service routinereturn: SETB EX1; open external interrupt 1pop accpop pswretiright: ...; right location entrance circuit interrupt serviceroutineAjmp Returnleft: ...; left Ranging entrance circuit interrupt service routineAjmp Return4, the calculation of ultrasonic propagation timeWhen you start firing at the same time start the single-chipcircuitry 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 receivercircuit 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 code is as follows:RECEIVE0: PUSH PSWPUSH ACCCLR EX0; related external interrupt 0MOV R7, TH0; read the time valueMOV R6, TL0?CLR CMOV A, R6SUBB A, # 0BBH; calculate the time differenceMOV 31H, A; storage resultsMOV A, R7SUBB A, # 3CHMOV 30H, ASETB EX0; open external interrupt 0POP ACCPOP PSWRETIFourth, the ultrasonic ranging system software designSoftware 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, each sequence of ultrasonic transmitting and receiving control.Interrupt service routines from time to time to complete three ofthe rotation direction of ultrasonic launch, the main external interrupt service subroutine to read the value of completion time, distance calculation, the results of the output and so on.V. 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 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 transistoramplifier 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.超声波测距系统的电路设计本文所介绍的三方向(前、左、右)超声波测距系统,就是为机器人了解其前方、左侧和右侧的环境而提供一个运动距离信息。
外文翻译毕业设计题目:超声波倒车雷达预警原文1:DISTANCE MEASURING AND MONITORING DEVICE EQUIPPED AUTOMOBILE REVERSE RADAR译文1:距离测量和监控设备装备汽车反向雷达原文2:ULTRASONIC SENSOR ASSEMBLY FOR AVEHICLE REVERSING RADAR译文2DISTANCE MEASURING AND MONITORING DEVICE EQUIPPED AUTOMOBILE REVERSE RADAR(原文1)This design relates to an automobile commutating radar, an ultrasonic sensor comprising the radar. The ordinary car commutation radar is usually installed in the rear bumper of a car. The vehicle has a commutation radar sensor, a ceramic chip in the polarization electric field, due to the reverse piezoelectric vibration of the aluminum housing and transmitting an ultrasonic signal, and receiving the reflected ultrasonic signal into an effective distance. Therefore, a driver will know that this situation is reversed in the rear of the vehicle do not have to stop looking for the front of the vehicle.A good ultrasonic sensor ultrasonic signal should be sent to a central area, produced a strong reaction in order to achieve a sensitive detection. The distance along the line of its axis with reference to Figure 5, a conventional ultrasonic sensor sensitive areas, the reception sensitivity in a test has 250 cm, and a sensitive, including 60 degree angle in the above 2 (X) cm. Thus, the conventional sensor performance has a low accuracyIn some vehicles, the most traditional ultrasonic sensor mounted in the front and rear bumpers. Vehicles of a monitor in a dashboard display, ultrasonic sensor detects an obstacle. However, with the conventional ultrasonic sensor has a sensitive wide angle, they must be installed in the end of the bumper to prevent the ultrasonic signals interfere with each other. However, the distance in each ultrasonic sensor is so large is still very low detection accuracy.In addition, when parking the vehicle, ultrasonic sensors often detect other vehicles parked next to the vehicle as an obstacle, so the driver may be a false alarm.Accordingly, the present design provides an improved ultrasonic sensors to reduce or eliminate the above problems.Summary of the designThe main purpose is to provide the design of an ultrasonic sensor sensitive to the radar has high precision long distance and a little sensitive to the angle of the car for. Other objectives, advantages and novel features of the design will become more apparent from the following detailed description together when an ultrasonic transducer assembly of the vehicle the commutation radar has an ultrasonic sensor and the two wires. A sleeve is received by the rubbermaterial and has a chamber sensor. A tapered opening that is defined in a front chamber. A wave guide cone is provided to open and close to the sensor in the center of the tapered. By using the sensor assembly, automotive radar there is a reversal of precision long detection distance in a concentrated area.The reference to the diagram, an ultrasonic sensor assembly for a car reversing radar, in accordance with the design consists of a sensor, a set, a guided wave cone, and a housing (ultrasonic sensor has a structure like traditional sensors, and two wires extending from sensors.Sleeve, usually made of rubber, there is one which is defined as the receiving sensor. A tapered shape of the opening is defined at the front and an opening formed on the lower side to prevent the ultrasonic signal reflected from the ground to cause false alarms. A flange formed on the rear of the sleeve.The definition channel for receiving signals. A rear cover is provided on the rear side of the space to encapsulate the sensor and the sleeve inside.In the assembled state shown in Figure 2, the guide wave cone installed you like bracket combination conical opening of the center of the casing and highlights. The heating wire extends the bracket backward and exit back cover. The sleeve is placed in the housing flange butt shoulder wires and heating wire extends from the back cover of the diaphragm. A pad, made of a resin or other soft material, is provided between the sleeve is An ci back cover, so the sleeve and the sensor housing can be stably received.Figure 4 illustrates a detector effect Contrast sensor and unguided wave cone, wherein the solid line illustrates the sensor wave guide cone, and the conflict lines described sensor without the guided wave taper. As shown in Figure 4, at a test frequency of about 40 kHz (35 kHz), gift of design of the sensor can be provided to an ultrasonic signal with a Federation higher than traditional sensors. Therefore, the design of detection better than traditional sensors作者:Joan Smith;Mike Howard ;国籍:USA出处:United States Patent距离测量和监控设备装备汽车反向雷达(译文1)本设计涉及一种汽车换向雷达,用一个超声波传感器组成该雷达。
毕业设计(论文)外文文献翻译文献、资料中文题目:超声测距系统设计文献、资料英文题目:Ultrasonic ranging system design 文献、资料来源:文献、资料发表(出版)日期:院(部):专业:班级:姓名:学号:指导教师:翻译日期: 2017.02.14Ultrasonic ranging system designPublication title: Sensor Review. Bradford: 1993.Vol.ABSTRACT: Ultrasonic ranging technology has wide using worth in many fields, 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 personnel for the ranging precision, the bound and the usage, a portable ultrasonic ranging system based on the single chip processor was developed.Keywords: Ultrasound, Ranging System, Single Chip Processor1. IntroductiveWith the development of science and techno logy, 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 construction 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. Comfort 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 robots, 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.2. A principle of ultrasonic distance measurementThe application of AT89C51:SCM is a major piece of computer components are integrated into the chip micro-computer. It is a multi-interface and counting on the micro-controller integration, and intelligence products are widely used in industrial automation. and MCS-51 microcontroller is a typical and representative.Microcontrollers are used in a multitude of commercial applications such as modems, motor-control systems, air conditioner control systems, automotive engine and among others. The high processing speed and enhanced peripheral set of these microcontrollers make them suitable for such high-speed event-based applications. However, these critical application domains also require that these microcontrollers are highly reliable. The high reliability and low market risks can be ensured by a robust testing process and a proper tools environment for the validation of these microcontrollers both at the component and at the system level. Intel Plaform Engineering department developed an object-oriented multi-threaded test environment for the validation of its AT89C51 automotive microcontrollers. The goals of this environment was not only to provide a robust testing environment for the AT89C51 automotive microcontrollers, but to develop an environment which can be easily extended and reused for the validation of several other future microcontrollers. The environment was developed in conjunction with Microsoft Foundation Classes(AT89C51).1.1 Features* Compatible with MCS-51 Products* 2Kbytes of Reprogrammable Flash MemoryEndurance: 1,000Write/Erase Cycles* 2.7V to 6V Operating Range* Fully Static operation: 0Hz to 24MHz* Two-level program memory lock* 128x8-bit internal RAM* 15programmable I/O lines* Two 16-bit timer/counters* Six interrupt sources*Programmable serial UART channel* Direct LED drive output* On-chip analog comparator* Low power idle and power down modes1.2 DescriptionThe AT89C2051 is a low-voltage, high-performance CMOS 8-bit microcomputer with 2Kbytes of flash programmable and erasable read only memory (PEROM). The device is manufactured using Atmel’s high density nonvolatile memory technology and is compatible with the industry standard MCS-51 instruction set and pinout. By combining a versatile 8-bit CPU with flash on a monolithic chip, the Atmel AT89C2051 is a powerful microcomputer which provides a highly flexible and cost effective solution to many embedded control applications.The AT89C2051 provides the following standard features: 2Kbytes of flash,128bytes of RAM, 15 I/O lines, two 16-bit timer/counters, a five vector two-level interrupt architecture, a full duplex serial port, a precision analog comparator, on-chip oscillator and clock circuitry. In addition, the AT89C2051 is designed with static logicfor operation down to zero frequency and supports two software selectable power saving modes. The idle mode stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue functioning. The power down mode saves the RAM contents but freezer the oscillator disabling all other chip functions until the next hardware reset.1.3 Pin Configuration1.4 Pin DescriptionVCC Supply voltage.GND Ground.Prot 1Prot 1 is an 8-bit bidirectional I/O port. Port pins P1.2 to P1.7 provide internal pullups. P1.0 and P1.1 require external pullups. P1.0 and P1.1 also serve as the positive input (AIN0) and the negative input (AIN1), respectively, of the on-chip precision analog comparator. The port 1 output buffers can sink 20mA and can drive LED displays directly. When 1s are written to port 1 pins, they can be used as inputs. When pins P1.2 to P1.7 are used as input and are externally pulled low, they will source current (IIL) because of the internal pullups.Port 3Port 3 pins P3.0 to P3.5, P3.7 are seven bidirectional I/O pins with internal pullups. P3.6 is hard-wired as an input to the output of the on-chip comparator and is not accessible as a general purpose I/O pin. The port 3 output buffers can sink 20mA. When 1s are written to port 3 pins they are pulled high by the internal pullups and can be used as inputs. As inputs, port 3 pins that are externally being pulled low will source current (IIL) because of the pullups.Port 3 also serves the functions of various special features of the AT89C2051 as listed below.1.5 Programming the FlashThe AT89C2051 is shipped with the 2 Kbytes of on-chip PEROM code memory array in the erased state (i.e., contents=FFH) and ready to be programmed. The code memory array is programmed one byte at a time. Once the array is programmed, to re-program any non-blank byte, the entire memory array needs to be erased electrically.Internal address counter: the AT89C2051 contains an internal PEROM address counter which is always reset to 000H on the rising edge of RST and is advanced applying a positive going pulse to pin XTAL1.Programming algorithm: to program the AT89C2051, the following sequence is recommended.1. power-up sequence:Apply power between VCC and GND pins Set RST and XTAL1 to GNDWith all other pins floating , wait for greater than 10 milliseconds2. Set pin RST to ‘H’ set pin P3.2 to ‘H’3. Apply the appropriate combination of ‘H’ or ‘L’ logic to pins P3.3, P3.4, P3.5,P3.7 to select one of the programming operations shown in the PEROM programming modes table.To program and Verify the Array:4. Apply data for code byte at location 000H to P1.0 to P1.7.5.Raise RST to 12V to enable programming.5. Pulse P3.2 once to program a byte in the PEROM array or the lock bits. The byte-write cycle is self-timed and typically takes 1.2ms.6. To verify the programmed data, lower RST from 12V to logic ‘H’ level and set pins P3.3 to P3.7 to the appropriate levels. Output data can be read at the port P1 pins.7. To program a byte at the next address location, pulse XTAL1 pin once to advance the internal address counter. Apply new data to the port P1 pins.8. Repeat steps 5 through 8, changing data and advancing the address counter for the entire 2 Kbytes array or until the end of the object file is reached.9. Power-off sequence: set XTAL1 to ‘L’ set RST to ‘L’Float all other I/O pins Turn VCC power off2.1 The principle of piezoelectric ultrasonic generatorPiezoelectric 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, it will be for vibration suppression of piezoelectric chip, the mechanical energy is converted to electrical signals, then it becomes the ultrasonic receiver.The traditio nal 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 intensity of the echo. As a consequence, a considerable error may occur even two echoes with different intensities arriving exactly at the same time 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 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, obstacles on his way to return immediately, the ultrasonic reflected wave received by the receiverimmediately 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), that is: s=340t / 23. Ultrasonic Ranging System for the Second Circuit 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 875, economic-to-use, and the chip has 4K of ROM, to facilitate programming.3.1 40 kHz ultrasonic pulse generated with the launchRanging system using the ultrasonic sensor of piezoelectric ceramic sensorsUCM40, 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 p1.0; output 40kHz square wavenop;nop;nop;djnz 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 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 ultrasonicUsed 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 determinetheir target bandwidth. R8-conditioning in the launch of 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 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 the 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:Receivel: push pswpush accclr ex1; related external interrupt 1jnb p1.1, right; P1.1 pin to 0, ranging from right to interrupt service routine circuitjnb p1.2, left; P1.2 pin to 0, to the left ranging circuit interrupt service routinereturn: SETB EX1; open external interrupt 1pop accpop pswretiright: …; right location entrance circuit interrupt service routineAjmp Returnleft: …; left ranging entrance circuit interrupt service routineAjmp Return3.3 The calculation of ultrasonic propagation timeWhen 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 output 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 code is as follows:RECEIVE0: PUSH PSWPUSH ACCCLR EX0; related external interrupt 0MOV R7, TH0; read the time valueMOV R6, TL0CLR CMOV A, R6SUBB A, #0BBH; calculate the time differenceMOV 31H, A; storage resultsMOV A, R7SUBB A, # 3CHMOV 30H, ASETB EX0; open external interrupt 0\POP ACCPOP PSWRETIFor 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 the amplitudes and 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 times and amplitudes of the echoes. If phase inversion occurs in the echo, determine to otherwise calculate to by interpolation using the amplitudes near the trough. Derive t sub m1 and t sub m2.Step 6: Calculation of the distance y using equation.4、The ultrasonic ranging system software designSoftware 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.Interrupt service routines from time to time to complete three of the rotation direction of ultrasonic launch, the main external interrupt service subroutine to read the value of completion time, distance calculation, the results of the output and so on.5、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 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 system.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.6、Parking sensor6.1 Parking sensor introductionReversing radar, full name is "reversing the anti-collision radar, also known as" parking assist device, car parking or reversing the safety of assistive devices, ultrasonic sensors(commonly known as probes), controls and displays (or buzzer)and other components. To inform the driver around the obstacle to the sound or a moreintuitive display to lift the driver parking, reversing and start the vehicle around tovisit the distress caused by, and to help the driver to remove the vision deadends and blurred vision defects and improve driving safety.6.2 Reversing radar detection principleReversing radar, according to high-speed flight of the bats in thenight, not collided with any obstacle principles of design anddevelopment. Probe mounted on the rear bumper, according to different price and brand, the probe only ranging from two, three, four, six, eight,respectively, pipe around. The probe radiation, 45-degree angle up and downabout the search target. The greatest advantage is to explore lower than the bumper of the driver from the rear window is difficult to see obstacles, and the police, suchas flower beds, children playing in the squatting on the car.Display parking sensor installed in the rear view mirror, it constantlyremind drivers to car distance behindthe object distance to the dangerous distance, the buzzer starts singing, allow the driver to stop. When the gear lever linked into reverse gear, reversing radar, auto-start the work, the working range of 0.3 to 2.0 meters, so stop when the driver was very practical. Reversing radar is equivalent to an ultrasound probe for ultrasonic probe can be divided into two categories: First, Electrical, ultrasonic, the second is to use mechanical means to produce ultrasound, in view of the more commonly used piezoelectric ultrasonic generator, it has two power chips and a soundingboard, plus apulse signal when the poles, its frequency equal to the intrinsic oscillation frequency of the piezoelectric pressure chip will be resonant and drivenby the vibration of the sounding board, the mechanical energy into electrical signal, which became the ultrasonic probe works. In order to better study Ultrasonic and use up, people have to design and manufacture of ultrasonic sound, the ultrasonic probe tobe used in the use of car parking sensor. With this principle in a non-contactdetection technology for distance measurement is simple, convenient and rapid, easyto do real-time control, distance accuracy of practical industrial requirements. Parking sensor for ranging send out ultrasonic signal at a givenmoment, and shot in the face of the measured object back to the signal wave, reversing radar receiver to use statistics in the ultrasonic signal from the transmitter to receive echo signals calculate the propagation velocity in the medium, which can calculate the distance of the probe and to detect objects.6.3 Reversing radar functionality and performanceParking sensor can be divided into the LCD distance display, audible alarm, and azimuth directions, voice prompts, automatic probe detection function is complete, reversing radar distance, audible alarm, position-indicating function. A good performance reversing radar, its main properties include: (1) sensitivity, whether theresponse fast enough when there is an obstacle. (2) the existence of blind spots. (3) detection distance range.6.4 Each part of the roleReversing radar has the following effects: (1) ultrasonic sensor: used tolaunch and receive ultrasonic signals, ultrasonic sensors canmeasure distance. (2) host: after the launch of the sine wave pulse to the ultrasonic sensors, and process the received signal, to calculate the distance value, the data and monitor communication. (3) display or abuzzer: the receivinghost from the data, and display the distance value and provide differentlevels according to the distance from the alarm sound.6.5 Cautions1, the installation height: general ground: car before the installation of 45 ~55: 50 ~ 65cmcar after installation. 2, regular cleaningof the probe to prevent the fill. 3, do not use the hardstuff the probe surface cover will produce false positives or ranging allowed toprobe surface coverage, such as mud. 4, winter to avoid freezing. 5, 6 / 8 probe reversing radar before and after the probe is not free to swap may cause the ChangMing false positive problem. 6, note that the probe mounting orientation, in accordance with UP installation upward. 7, the probe is not recommended to install sheetmetal, sheet metal vibration will cause the probe resonance, resulting in false positives.超声测距系统设计原文出处:传感器文摘布拉福德:1993年超声测距技术在工业现场、车辆导航、水声工程等领域具有广泛的应用价值,目前已应用于物位测量、机器人自动导航以及空气中与水下的目标探测、识别、定位等场合。
摘要随着社会的发展,人们对距离或长度测量的要求越来越高。
在社会生活中应用超声波测距技术已很广泛,如汽车倒车雷达、测距仪和物位测量仪等都可以通过超声波来实现。
由于超声波指向性强,能量消耗缓慢,在介质中传播的距离较远,因而超声测距技术的研究和开发具有实际意义。
本文介绍了一种利用超声波测距的系统,该系统是一种基于STC12C2052 单片机的超声波测距系统,它根据超声波在空气中传播的反射原理,以超声波传感器为检测部件,应用单片机技术和超声波在空气中的时间差来测量距离。
该系统主要由主控制器模块、超声波发射模块、超声波接收模块和显示模块等四个模块构成。
通过单片机的I/O口控制超声波发射电路发出40KHz的超声波,反射波经由超声波检测接收电路、放大电路送入单片机外部中断端,通过计算超声波的发射和返回的时间,确定超声波发生器和反射物体之间的距离,完成测距。
该系统可实现4米内测距,盲区20厘米。
关键词:超声波;测距;单片机AbstractWith the development of society, the demand on the measurement of distance or length is increasing. It is applied widely by ultrasonic to measure distance,such as cars reversing radar,range finder and level measurement and so on.Because of the strong point of ultrasonic, low energy consumption,long distance transporting in media, thus it is practical and significant to measure distance by ultrasonic.In this paper ,it introduces a system to measure distance by ultrasonic,which is based on the STC12C2052.The theory is based on the principles of reflection of ultrasonic spreading in the air. The system uses ultrasonic sensors as a detector, and applies MCU and the time difference of ultrosonic spreading in the air to measure the distance. The system consists of the main controller module, ultrasonic transmitter module, ultrasonic receiver module and display module. The MCU I / O port controls ultrasonic transmitter to send 40 KHz ultrasonic, and the reflecting singal is received by the ultrasonic receiver circuit, and it is amplified,and finally,it starts the interruptor of the MCU.The MCU calculates the time of launch and return of ultrasonic to get the disctance between the ultrasonic generator and the reflective objects. The range of measurement is within four meters,with the blind spot of 20 cm。
单片机外文翻译外文文献英文文献基于单片机的超声波测距系统的研究与设计附录附录A外文翻译the equivalent dc value. In the analysis of electronic circuits to be considered in a later course, both dc and ac sources of voltage will be applied to the same network. It will then be necessary to know or determine the dc (or average value) and ac components of the voltage or current in various parts of the system.EXAMPLE 13.13 Determine the average value of the waveforms of Fig. 13.37.FIG. 13.37Example 13.13.Solutions:a. By inspection, the area above the axis equals the area below over one cycle, resulting in an average value of zero volts.b. Using Eq.(13.26):as shown in Fig. 13.38.26In reality, the waveform of Fig. 13.37(b) is simply the square wave of Fig. 13.37(a) with a dc shift of 4 V; that is v2 =v1 + 4 VEXAMPLE 13.14 Find the average values of the following waveforms over one full cycle:a. Fig. 13.39.b. Fig. 13.40.27Solutions:We found the areas under the curves in the preceding example by using a simple geometric formula. If we should encounter a sine wave or any other unusual shape, however, we must find the area by some other means. We can obtain a good approximation of the area by attempting to reproduce the original wave shape using a number of small rectangles or other familiar shapes, the area of which we already know through simple geometric formulas. For example,the area of the positive (or negative) pulse of a sine wave is 2Am. Approximating this waveform by two triangles (Fig. 13.43), weobtain(using area1/2 base height for the area of a triangle) a rough idea of the actual area:A closer approximation might be a rectangle with two similar triangles(Fig. 13.44):28which is certainly close to the actual area. If an infinite number of forms were used, an exact answer of 2Am could be obtained. For irregular waveforms, this method can be especially useful if data such as the average value are desired. The procedure of calculus that gives the exact solution 2Am is known as integration. Integration is presented here only to make the method recognizable to the reader; it is not necessary to be proficient in its use to continue with this text. It is a useful mathematical tool, however,and should be learned. Finding the area under the positive pulse of a sine wave using integration, we havewhere ? is the sign of integration, 0 and p are the limits of integration, Am sin a is thefunction to be integrated, and da indicates that we are integrating with respect to a.Integrating, we obtainSince we know the area under the positive (or negative) pulse, we can easily determine the average value of the positive (or negative) region of a sine wave pulse by applying Eq. (13.26):For the waveform of Fig. 13.45,29EXAMPLE 13.15 Determine the average value of the sinusoidal waveform of Fig. 13.46.Solution: By inspection it is fairly obvious thatthe average value of a pure sinusoidal waveform over one full cycle is zero.EXAMPLE 13.16 Determine the average value of the waveform of Fig. 13.47.Solution: The peak-to-peak value of the sinusoidal function is16 mV +2 mV =18 mV. The peak amplitude of the sinusoidal waveform is, therefore, 18 mV/2 =9 mV. Counting down 9 mV from 2 mV(or 9 mV up from -16 mV) results in an average or dc level of -7 mV,as noted by the dashed line of Fig. 13.47.EXAMPLE 13.17 Determine the average value of the waveform of Fig. 13.48.Solution:30EXAMPLE 13.18 For the waveform of Fig. 13.49, determine whether the averagevalue is positive or negative, and determine its approximate value.Solution: From the appearance of the waveform, the average value is positive and in the vicinity of 2 mV. Occasionally, judgments of this type will have to be made. InstrumentationThe dc level or average value of any waveform can be found using a digital multimeter (DMM) or an oscilloscope. For purely dccircuits,simply set the DMM on dc, and readthe voltage or current levels.Oscilloscopes are limited to voltage levels using the sequence of steps listed below:1. First choose GND from the DC-GND-AC option list associated with each vertical channel. The GND option blocks any signal to which the oscilloscope probe may be connected from entering the oscilloscope and responds with just a horizontal line. Set the resulting line in the middle of the vertical axis on the horizontal axis, as shown in Fig. 13.50(a).2. Apply the oscilloscope probe to the voltage to be measured (ifnot already connected), and switch to the DC option. If a dc voltage is present, the horizontal line will shift up or down, as demonstrated in Fig. 13.50(b). Multiplying the shift by the vertical sensitivity will result in the dc voltage. An upward shift is a positive voltage (higher31potential at the red or positive lead of the oscilloscope), while a downward shift is a negative voltage (lower potential at the red or positive lead of the oscilloscope). In general,1. Using the GND option, reset the horizontal line to the middle of the screen.2. Switch to AC (all dc components of the signal to whichthe probe is connected will be blocked from entering the oscilloscope—only the alternating, or changing,components will be displayed).Note the location of some definitive point on the waveform, such as the bottom of the half-wave rectified waveform of Fig. 13.51(a); that is, note its position on the vertical scale. For the future, whenever youuse the AC option, keep in mind that the computer will distribute the waveform above and below the horizontal axis such that the average value is zero; that is, the area above the axis will equal the area below. 3. Then switch to DC (to permit both the dc and the ac components of the waveform to enter the oscilloscope), and note the shift in the chosen level of part 2, as shown in Fig. 13.51(b). Equation(13.29) can then be used to determine the dc or average value of the waveform. For the waveform of Fig. 13.51(b), the average value is aboutThe procedure outlined above can be applied to any alternating waveform such as the one in Fig. 13.49. In some cases the average valuemay require moving the starting position of the waveform under the AC option to a different region of the screen or choosing a higher voltage scale. DMMs can read the average or dc level of any waveform by simply choosing the appropriate scale.3213.7 EFFECTIVE (rms) VALUESThis section will begin to relate dc and ac quantities with respect to the power delivered to a load. It will help us determine the amplitude of a sinusoidal ac current required to deliver the same power as a particular dc current. The question frequently arises, How is it possible for a sinusoidal ac quantity to deliver a net power if, over a full cycle, the net current in any one direction is zero (average value 0)? It would almost appear that the power delivered during the positive portion of the sinusoidal waveform is withdrawn during the negative portion, and since the two are equal in magnitude, the net power delivered is zero. However, understand that irrespective of direction, currentof any magnitude through a resistor will deliver power to that resistor. In other words,during the positive or negative portions of a sinusoidal ac current, power is being delivered at eachinstant of time to the resistor. The power delivered at each instant will, of course, vary with the magnitude of the sinusoidal ac current, but there will be a net flow during either the positive or the negativepulses with a net flow over the full cycle. The net power flow will equal twice that delivered by either the positive or the negative regions of sinusoidal quantity. A fixed relationship between ac and dc voltages and currents can be derived from the experimental setup shown in Fig. 13.52. A resistor in a water bath is connected by switches to a dc and an ac supply. If switch 1 is closed, a dc current I, determined by the resistance R and battery voltage E, will be established through theresistor R. The temperature reached by the water is determined by the dc power dissipated in the form of heat by the resistor.If switch 2 is closed and switch 1 left open, the ac current through the resistor will have a peak value of Im. The temperature reached by the water is now determined by the ac power dissipated in the form of heat by the resistor. The ac input is varied until the temperature is the same as that reached with the dc input. When this is accomplished, the average electrical power delivered to the resistor R by the ac source is the same asthat delivered by the dc source. The power delivered by the ac supply at any instant of time is33The average power delivered by the ac source is just the first term, since the average value of a cosine wave is zero even though the wave may have twice the frequency of the original input current waveform. Equating the average power delivered by the ac generator to that delivered by the dc source,which, in words, states thatthe equivalent dc value of a sinusoidal current or voltage is 1/2 or 0.707 of itsmaximum value.The equivalent dc value is called the effective value of the sinusoidal quantity.In summary,As a simple numerical example, it would require an ac current with a peak value of 2 (10) 14.14 A to deliver the same power to the resistorin Fig. 13.52 as a dc current of 10 A. The effective value of any quantity plotted as a function of time can be found by using the following equation derived from the experiment just described:34which, in words, states that to find the effective value, the function i(t) must first besquared. After i(t) is squared, the area under the curve isfound by integration. It is then divided by T, the length of the cycle or the period of the waveform, to obtain the average or mean value of thesquared waveform. The final step is to take the square root of the meanvalue. This procedure gives us another designation forthe effectivevalue, the root-mean-square (rms) value. In fact, since therms term isthe most commonly used in the educational and industrial communities,it will used throughout this text. EXAMPLE 13.19 Find therms values of the sinusoidal waveform in each part of Fig. 13.53.Solution: For part (a), Irms 0.707(12 10 3 A) 8.484 mA.For part (b), againIrms 8.484 mA. Note that frequency did notchange the effective valuein (b) above compared to (a). For part (c),Vrms 0.707(169.73 V) 120 V, the same as available from a home outlet.EXAMPLE 13.20 The 120-V dc source of Fig. 13.54(a) delivers 3.6 W to the load. Determine the peak value of the applied voltage (Em) and the current (Im) if the acsource [Fig. 13.54(b)] is to deliver the same power to the load.35Solution:EXAMPLE 13.21 Find the effective or rms value of the waveform of Fig.13.55.Solution:36EXAMPLE 13.22 Calculate the rms value of the voltage of Fig. 13.57.Solution:EXAMPLE 13.23 Determine the average and rms values of the square wave of Fig. 13.59.37Solution: By inspection, the average value is zero.The waveforms appearing in these examples are the same as thoseused in the examples on the average value. It might prove interesting tocompare the rms and average values of these waveforms.The rms values of sinusoidal quantities such as voltage or currentwill be represented by E and I. These symbols are the same as thoseused for dc voltages and currents. To avoid confusion, the peak valueof a waveform will always have a subscript m associated with it: Imsin qt. Caution: When finding the rms value ofthe positive pulse of asine wave, note that the squared area is not simply (2Am)24A2m; itmust be found by a completely new integration. This will always bethe case for any waveform that is not rectangular.A uniquesituation arises if a waveform has both a dc and an ac componentthat may be due to a source such as the one in Fig. 13.61. Thecombination appears frequently in the analysis of electronic networkswhere both dc and ac levels are present in the same system.38The question arises, What is the rms value of the voltage vT? Onemight be tempted tosimply assume that it is the sum of the rms valuesof each component of the waveform; that is, VT rms 0.7071(1.5 V) 6 V 1.06 V 6 V 7.06 V. However, the rms value is actuallydetermined bywhich for the above example is39直流值相等。
International Journal of Computer science & Information Technology (IJCSIT), Vol 1, No 2, November 2009EFFECT OF VARIATION OF SEPARATION BETWEEN THE ULTRASONIC TRANSMITTER AND RECEIVER ON THE ACCURACY OF DISTANCE MEASUREMENTAjay Kumar Shrivastava1, Ashish Verma2 and S. P. Singh31Department of Computer Application, Krishna Institute of Engineering and Technology, Ghaziabad (U.P.), Indiaajay@2Department of Physics and Electronics, Dr H S Gour University, Sagar (M.P.), Indiavermaashish31@3Department of Electronics and Communication, Noida Institute of Engineering and Technology, Ghaziabad (U.P.), Indiasahdeopsingh@ABSTRACTAccuracy of distance measurement of an object from an observation point such as a stationary or moving vehicle, equipment or person is most important in large number of present day applications. Ultrasonic sensors are most commonly used due to its simplicity and low cost. The accuracy of the measured distance is dependent on the separation between the ultrasonic transmitter and receiver. This dependency has been studied and reported in this paper. The result shows that the accuracy of distance measured is dependent on the separation between the transmitter and the receiver.KEYWORDSAccuracy of distance measurement, Ultrasonic sensor, distance measurement, microcontroller, sewer pipeline inspection, sewer pipeline maintenance, robotics.1. INTRODUCTIONDistance measurement of an object in front or by the side of a moving or stationary entity is required in a large number of devices and gadgets. These devices may be small or large and also quite simple or complicated. Distance measurement systems for such applications are available. These use various kinds of sensors and systems. Low cost and accuracy as well as speed are important in most of the applications. Hence ultrasonic sensors are most commonly used. To maintain the accuracy of measured distance the separation between transmitter and receiver is very important. In this paper, we describe the results of a study on the variation of error of measurement of distance of an object by varying the separation between the transmitter and receiver of the ultrasonic sensors by using microcontroller P89C51RD2. Ultrasound sensors are very versatile in distance measurement. They are also providing the cheapest solutions. Ultrasound waves are suitable both for air and underwater use [1].19International Journal of Computer science & Information Technology (IJCSIT), Vol 1, No 2, November 2009Ultrasonic sensors are also quite fast for most of the common applications. In simpler system a low cost version of 8- bit microcontroller can be used to implement the system to lower the cost. We are applying this system for sewer inspection system. Sewer blockages have become quite common. The blockages have become more frequent due to the dumping of polythene bags, hair and solid materials into the sewer system [2], [3]. There has been no work done in this direction. This is a new study which is useful to find out the optimal separation between ultrasonic transmitter and receiver to measure small distances.2. PRINCIPLEUltrasonic transducer uses the physical characteristics and various other effects of ultrasound of a specific frequency. It may transmit or receive the ultrasonic signal of a particular strength. These are available in piezoelectric or electromagnetic versions. The piezoelectric type is generally preferred due to its lower cost and simplicity to use [5]. The transmitter and receiver are available either as single unit or as separate units. The Ultrasonic wave propagation velocity in the air is approximately 340 m/s, the same as sonic velocity. To be precise, the ultrasound velocity is governed by the medium, and the velocity in the air is calculated using the formula given below (1). V= 340+0.6(t-15) m/s t:temperature, °C (1)In this study, we assumed the temperature to be 20°C, so the velocity of ultrasound in the air is 343 m/s. Because the travel distance is very short, the travel time is little affected by temperature. It takes approximately 29.15µsec for the ultrasound to propagate through 1cm, so it is possible to have 1cm resolution in the system [6].3. EXPERIMENTAL SETUPThe system consists of a transmitter and a receiver module controlled by a microcontroller P89C51RD2. We have used a microcontroller development kit for testing of the system. We are using 40Khz ultrasound sensors for our experiments. The Simplified block diagram of the system is shown in Fig.1. In Fig. 1, the interrupt1 signal initiates the system. When the interrupt1 signal is generated, MCU starts the timer1 to measure time and simultaneously generates the controlled 40Khz pulses having a train of specific number of pulses. These pulses are applied to the amplifier circuit and after amplification the ultrasound transmitter transmits the pulse train in the direction of the object. These ultrasonic pulses are reflected from the object and travels back in different directions. These reflected waves arrive at receiver. After amplification and processing it generates signal interrupt. This is applied as interrupt2 to the MCU. Interrupt2 stops the timer1, and MCU calculates the time elapsed between the generation of the wave and reception of the wave. This time is proportional to the distance travelled by the waves. Using the formula, MCU calculates the distance of the obstacle and display it or transfer it to the part of the total system where it is used for further control. Using this elapsed time, we calculate the distance of the object from the ultrasonic sensors.20International Journal of Computer science & Information Technology (IJCSIT), Vol 1, No 2, November 2009INT1 MCU Ultrasound Transmitter CircuitTINT2 Receiver Amplifier Display RFig 1: Block Diagram of the System4. EXPERIMENTAL RESULTSThe waveforms of the transmitted and received waveforms of the ultrasonic signal is stored in Digital Storage Oscilloscope. We have taken the readings for various separation between tranmitter and reciever. We have measured the distance in the interval of 5cm. For every measured distance three reading have been taken. The table shows the average of the three readings. The maesured distance is calculated on the basis of travelled time. The formula to calculate the distance is given below: Dist. (cm) = (Travelled Time*10-6 * 34300) / 2 (2)The ultrasonic waves travelled from the transmitter to the object and from the object back to the receiver hence the whole distance is divided by two. Values of %Error have also been calculated and shown. The error result shows that there is some error in recording the start and finish times in the system. When the distance increases the error is distributed in a larger distance and hence the %error decreases. We have taken the measurements for various separations of transmitter and receiver renging from 2cm to 15cm. The Table 1 shows the results when separation between tranmitter and reciever is 2cm. Table 1: Experimental Results (For 2cm Separation between Transmitter and Reciever) S.No . 1 2 3 4 5 6 7 8 9 10 Actual Distance(cm) 5 10 15 20 25 30 35 40 45 50 Travelled Time (µSec) 400 690 1050 1250 1650 1930 2180 2400 2700 3000 Measured Distance (cm) 6.86 11.83 18.01 21.44 28.30 33.10 37.39 41.16 46.31 51.45 % Error 37.20 18.34 20.05 7.19 13.19 10.33 6.82 2.90 2.90 2.90The result shows that the acuracy of measured distance is increses for longer distances. The %error becomes constant for measured distances above 40cm. The highest %error is occured in small distance of 5cm. It is also shown by Fig.2.21International Journal of Computer science & Information Technology (IJCSIT), Vol 1, No 2, November 2009Fig. 2: Graph of Actual Distance versus Measured Distance for 2cm Separation between Transmitter and Reciever. The Table 2 shows the result when separation between transmitter a reciever is 5cm. Table 2: Experimental Results for 5cm Separation between Transmitter and reciever) S.No. 1 2 3 4 5 6 7 8 9 10 Actual Distance(cm) 5 10 15 20 25 30 35 40 45 50 Travelled Time (µSec) 410 700 1000 1300 1600 1870 2220 2500 2780 3120 Measured Distance (cm) 7.03 12.01 17.15 22.30 27.44 32.07 38.07 42.88 47.68 53.51 % Error 40.63 20.05 14.33 11.48 9.76 6.90 8.78 7.19 5.95 7.02The resluts shows that the accuracy is incresed in camparison to the previous results. This is also shown by the Fig. 3.Fig. 3: Graph of Actual Distance versus Measured Distance when Separation between Transmitter and Reciever is 5 cm.22International Journal of Computer science & Information Technology (IJCSIT), Vol 1, No 2, November 2009The Table 3 shows the results when separation between transmitter and reciever is 10 cm. These results indicates that when we increase the separation between transmitter and receiver the %error increses for small measured distances. Table 3: Experimental Results for Separation of 10cm between Transmitter and reciever)S.No. 1 2 3 4 5 6 7 8 9 10Actual Distance(cm) 5 10 15 20 25 30 35 40 45 50Travelled Time (µSec) 620 750 1010 1310 1600 1870 2200 2400 2680 3000Measured Distance (cm) 10.63 12.86 17.32 22.47 27.44 32.07 37.73 41.16 45.96 51.45% Error 112.66 28.63 15.48 12.33 9.76 6.90 7.80 2.90 2.14 2.90Again the accuracy increases with the distance but the small distances are not so accurate. The error is high for small distances. It is also shown by the Fig. 4.Fig. 4: Graph of Actual Distance versus Measured Distance when Separation between Transmitter and Reciever is 10 cm. The Table 4 is showing the result of measured distance when 15cm separation between transmitter and reciever. These results shows that when we increase the separation between transmitter and receiver the %error increses. This increase is very high in small measured distances like 5cm in our experiment. The lowest %error observed for the measured distance of 45cm and again it is increasing for the measured distance of 50cm. The results shows that we have to stop the increament of seaparation between transmitter and receiver in our experiment.23International Journal of Computer science & Information Technology (IJCSIT), Vol 1, No 2, November 2009Table 4: Experimental Results for 15cm Separation between Transmitter and Reciever) S.No. 1 2 3 4 5 6 7 8 9 10 Actual Distance(cm) 5 10 15 20 25 30 35 40 45 50 Travelled Time (µSec) 1300 930 1180 1350 1620 1900 2200 2420 2700 3200 Measured Distance (cm) 22.30 15.95 20.24 23.15 27.78 32.59 37.73 41.50 46.31 54.88 % Error 345.90 59.50 34.91 15.76 11.13 8.62 7.80 3.76 2.90 9.76Again the error for the small distance say 5cm is very high. It is also showing that the graph between actual distance versus measured distance is not a straight line. This graph is shown in Fig. 5.Fig. 5: Graph of Actual Distance versus Measured Distance for 15cm Separation between Transmitter and Reciever. The graph between the measured distance the actual distance indicates that the measured distance is proportional to the actual distance.5. ANALYSIS OF THE RESULTSThe experimental results shows that the distance measured for different separations between transmitter and receiver are accurate for long distances e.g. more than 20cm. For small actual distances say 5cm, the small transmitter and receiver distances are better in comparison to the long distances between transmitter and receiver. If we place the transmitter and receiver at 15cm separation than the small distance like 5cm are not going to be measured correctly. Result shows the error of 345%. Hence we have to place the transmitter and receiver at proper distance like 5-10cm. For long distances the distance between transmitter and receiver has very low impact on the accuracy. We have compared the all measured distances for different separations between transmitter and receiver and the results are shown in the Table 5.24International Journal of Computer science & Information Technology (IJCSIT), Vol 1, No 2, November 2009Table 5: Comparison of Measured Distances for different Separations between Transmitter and Reciever Actual Dist. (cm) 5 10 15 20 25 30 35 40 45 50 Measured Distance (in cm) when Separation between Transmitter and Reciever is = 2cm 6.86 11.83 18.01 21.44 28.30 33.10 37.39 41.16 46.31 51.45 5cm 7.03 12.01 17.15 22.30 27.44 32.07 38.07 42.88 47.68 53.51 10cm 10.63 12.86 17.32 22.47 27.44 32.07 37.73 41.16 45.96 51.45 15cm 22.30 15.95 20.24 23.15 27.78 32.59 37.73 41.50 46.31 54.88S. No. 1 2 3 4 5 6 7 8 9 10As we can see in the table that small measured distance like 5cm is measured accurately when 2cm separation between transmitter and receiver. It has the lowest error. When we increase the distance to be measured, the accuracy of measured distance are high and it the highest for 10cm separation between transmitter and receiver. Hence for the range of 5cm to 50cm, as we taken in our experiments, the separation between transmitter and receiver are 2cm to 10cm. If we increase this than the error percentage also increases. The Fig.6 shows the graph between actual distance and the different measured distances for various separations between transmitter and receiver.Fig. 6: Graph for Comparison of Measured Distances for different Separations between Transmitter and Reciever This graph is also showing that the graph plotting of measured distance when separation between transmitter and receiver is 2cm, 5cm and 10cm is almost on the same points. The graph plotting when 15cm separation between transmitter and receiver, is not very encouraging for this range of 5cm to 50cm.25International Journal of Computer science & Information Technology (IJCSIT), Vol 1, No 2, November 20096. CONCLUSIONSWe have done the experiments on our ultrasonic measurement system for the various separations between transmitter and receiver and the result shows that the measured distance is satisfactory for our study. When the distance increases the error becomes constant and very less. A correction may be applied to calculate the correct distance. Interrupt1 initiates the system and interrupt2 stops the timer and on the basis of the travelled time distance calculated. In future, the whole system will be mounted on the one PCB. This study shows that for small distances the separation between transmitter and receiver should be 5cm to 10cm. Hence this study will help in fixing the separation between transmitter and receiver in the robotic vehicle for blockage detection so we are able to calculate the more accurate distance of the blockage in the sewage filled sewer lines. Hence we can prevent human labour to go in the sewage filled sewer lines to detect the blockage which are very dangerous to the human as they contain the poisonous gases.ACKNOWLEDGMENTThis work is supported by MP Council of Science and Technology (MPCST), Bhopal, Project Code No. R&D/PHYSICS.23/08-09-1.REFERENCES[1] J. David and N cheeke “Fundamentals of Ultrasonic Waves” CRC Press, Florida, USA, 2002, ISBN 0-8493-0130-0. [2] Singh SP, Verma Ashish, Shrivastava AK “Design and Development of Robotic Sewer Inspection Equipment Controlled by Embedded Systems” Proceedings of the First IEEE International Conference on Emerging Trends in Engineering and Technology, July 16-18, 2008, Nagpur, India pp. 1317-1320. [3] Shrivastava AK, Verma Ashish, Singh SP “Partial Automation of the Current Sewer Cleaning System”, Invertis Journal of Science and Technology, Vol.1, No.4, 2008, pp 261-265. [4] O. Duran, K.Althoefer, and L Seneviratene, “State of the Art in Sensor Technologies for Sewer Inspection”, IEEE Sensors Journal, April 2002, Vol. 2, N.2, pp 63. [5] Hongjiang He, Jianyi Liu, “The Design of Ultrasonic Distance Measurement System Based on S3C2410” Proceedings of the 2008 IEEE International Conference on Intelligent Computation Technology and Automation, 20-22 Oct, 2008, pp. 44-47. [6] Yongwon Jang, Seungchul Shin, Jeong Won Lee, and Seunghwan Kim, “A Preliminary Study for Portable Walking Distance Measurement System Using Ultrasoinc Sensors” Proceedings of the 29th Annual International Conference of the IEEE EMBS Cité Internationale Lyon, France, Aug 23-26, 2007, pp. 5290-5293.26International Journal of Computer science & Information Technology (IJCSIT), Vol 1, No 2, November 2009AuthorsAjay Kumar Shrivastava was born at Guna (M.P.), India on 7th August, 1977. He had done his graduation in Electronics from Dr. H.S.Gour University, Sagar (M.P.), India in 1998. After that he had completed his MCA from the same university in 2002. He has more than seven years of teaching experience. He had worked as Lecturer in Technocrats Institute of Technology, Bhopal (M.P.), India for three years. Presently he is working as Associate Professor in Krishna Institute of Engineering and Technology, Ghaziabad (U.P.), India from Aug. 2005. His research interests include Embedded Systems and Data Mining. Mr. Shrivastava is the life member of Computer Society of India (CSI). He is also life member of Association of Computer, Electronics and Electrical Engineers (ACEEE) and International Association of Computer Science and Information Technology (IACSIT) and International Association of Engineers (IAENG). He is also the member of Computer Science Teachers Association (CSTA). He is also reviewer of various ACEEE organized conferences. He has published a paper in National Journal and published/presented four papers in conferences.Dr. Ashish Verma was born on 23rd March 1963. He received the M.Sc. degree in Physics with specialization in Electronics and solidstate physics in1984 and Ph.D. degree in Physics in 1991 from Dr. Hari Singh Gour Central University, Sagar, (M.P.), India. He has having 24 years of teaching (UG/PG) and research experience and is currently working as a Senior Lecturer in the department of Physics and Electronics, Dr. Hari Singh Gour Central University, Sagar. He has guided about 150 students (UG/PG) for their projects in the field of Electronics and Physics. He guided 4 Ph.D. students (One as Co-Supervisor). Presently, he is guiding 8 Ph.D. students for their innovative research. He is supervising 3 Ph.D. students in Physics and Electronics of M.P. BHOJ (Open) University, Bhopal, (M.P.), India. He had published a book entitled “Microprocessor”, Vishwavidyalaya Prakashan, Sagar (M.P.), India and written two chapters in “Bhotiki”, Madhya Pradesh Hindi Granth Academy, Bhopal (M.P.), India. Dr. Verma published / presented about 50 research papers in the National /International Journals / Conferences of high repute. He is the Executive Council (Government Nominee) in Government Girls Autonomous College, Sagar, (M.P.). He had worked in various committees of the university. Prof. S.P.Singh was born at village Manirampur in Nalanda district, Bihar, India on 10th June 1939. He did his schooling and intermediate studies at Patna. He completed his B.Sc.(Engg.) degree in Electrical Engineering from National Institute of Technology, Jamshedpur, India in the year 1964. He did M.Tech. in Electrical Engineering (Electronic Devices and Circuits) from Indian Institute of Technology, Kanpur, India in 1975. He obtained his Ph.D. degree from Ranchi University, Ranchi, India in the year 1993. His topic was microprocessor based speed control of induction motors.27International Journal of Computer science & Information Technology (IJCSIT), Vol 1, No 2, November 2009He joined N.I.T., Jamshedpur, India as Lecturer in Electrical Engineering in 1964 continued there as lecturer, AP and Professor till 1999. He started teaching electronic subjects and shifted to electronics engineering. After retirement from NIT in 1999, he continued to work as professor in institutes around Delhi. Currently, he is working as professor in Electronics & Communication Engineering at Noida Institute of Engineering and Technology, Greater Noida, U.P., India. Prof. Singh was a member of IEEE from 1974 to 1991. At present Dr. Singh is a fellow of I.E.T.E., India.28。
毕业设计(论文)英文资料翻译Ultrasonic ranging system design系别专业班级学生姓名学号指导教师中文翻译超声测距系统设计摘要:超声测距技术在工业现场、车辆导航、水声工程等领域都具有广泛的应用价值,目前已应用于物位测量、机器人自动导航以及空气中与水下的目标探测、识别、定位等场合。
因此,深入研究超声的测距理论和方法具有重要的实践意义。
为了进一步提高测距的精确度,满足工程人员对测量精度、测距量程和测距仪使用的要求,本文研制了一套基于单片机的便携式超声测距系统。
关键词:超声波,测距仪,单片机1.前言随着科技的发展,人们生活水平的提高,城市发展建设加快,城市给排水系统也有较大发展,其状况不断改善。
但是,由于历史原因合成时间住的许多不可预见因素,城市给排水系统,特别是排水系统往往落后于城市建设。
因此,经常出现开挖已经建设好的建筑设施来改造排水系统的现象。
城市污水给人们带来了困扰,因此箱涵的排污疏通对大城市给排水系统污水处理,人们生活舒适显得非常重要。
而设计研制箱涵排水疏通移动机器人的自动控制系统,保证机器人在箱涵中自由排污疏通,是箱涵排污疏通机器人的设计研制的核心部分。
控制系统核心部分就是超声波测距仪的研制。
因此,设计好的超声波测距仪就显得非常重要了。
2.SCM描述微控制器(MCU)是一种单片计算机。
这是一种强调自给自足和成本效益形成鲜明对比的通用微处理器(PC)。
现在使用的大多数的计算机系统是嵌入到其他机器中,如电话、时钟、电器、汽车和基础设施。
嵌入式系统通常对内存和程序长度的要求很小并且可能需要简单但不寻常的输入/输出系统。
例如,大多数嵌入式系统缺乏键盘,屏幕,磁盘、打印机或其他可辨认的个人计算机的I/O设备。
他们可能控制电动机、继电器或电压和阅读开关、可变电阻或者其他电子设备。
通常情况下,人类可读的唯一的I/O设备是一个发光二极管,严重的甚至可以消除这种成本或权力约束。
与通用CPU相比,微控制器没有一个地址总线或一个数据总线,因为他们整合了所有的内存和非易失性内存相同的芯片CPU。
英文原文:Ultrasonic distance sensorDesign Principles:Ultrasonic sensor is developed from the use of the characteristics of ultrasonic sensors.Higher frequency ultrasound is a mechanical acoustic waves, the transducer excitation voltage of the chip occurs in the vibration, and it has a high frequency, short wavelength, diffraction is small, especially the direction of good, to be the ray and the orientationcommunication and so on.Ultrasound on liquids and solids through a great ability, especially in opaque solids in the sun, which can penetrate tens of meters in depth.Ultrasonic impurities or sub-interface will encounter a significant reflection reflection into the echo formation, hit moving objects can produce the Doppler effect.Therefore widely used in industrial ultrasonic inspection, defense, biomedical and other aspects of the ultrasound as a means of detection, must generate and receive ultrasound ultrasound.To fulfill this function the device is ultrasonic sensors, traditionally known as the ultrasonic transducer or ultrasonic probe.The main performance indicators of ultrasonic sensors:Ultrasound probe is the core of its plastic jacket or a piece of metal in the piezoelectric jacket.Constitute the chip can have many kinds of materials.Chip size, such as diameter and thickness also vary, so the performance of each probe is different, we used to know it in advance before the performance.The main performance indicators of ultrasonic sensors include: (1) operating frequency.Frequency is the resonant frequency of the piezoelectric wafer.When added to the AC voltage across it, and the frequency of the resonant frequency of the chip are equal, the maximum energy output, sensitivity is highest.(2) operating temperature.Since the Curie point of piezoelectric materials generally high, particularly when using the power of diagnostic ultrasound probe small, so the temperature is relatively low, you can work long hours without producing failure.Medical ultrasound probe temperature is relatively high, requiring a separate cooling device.(3) sensitivity.Depends primarily on manufacturing the chip itself.Electromechanical coupling coefficient, high sensitivity; the other hand, low sensitivity.Structure and Working Principle:When voltage is applied to piezoelectric ceramic, it will with the voltage and frequency of changes in the mechanical deformation.On the other hand, when the vibration of piezoelectric ceramics, it will generate a ing this principle, when given by the two piezoelectric ceramic or a piezoelectric ceramic and a vibrator, sheet metal, the so-called bimorph element called the imposition of an electricalsignal, it will emit ultrasonic vibration due to bending.Conversely, when applied to the bimorph ultrasonic devices, it will generate an electrical signal.Based on the above role, it can be used as a piezoelectric ceramic ultrasonic sensors.Such as ultrasonic sensors, a compound vibrator was flexibility on a fixed base.The vibrator is a composite resonator, and by a metal plate and a piezoelectric bimorph element consisting of a combination vibrator.Resonator and trumpets the purpose of effective radiation generated by the ultrasonic vibrations, and can effectively make ultrasonic vibrator gathered in a central location.Outdoor uses ultrasonic sensors must have a good seal in order to prevent dew, rain and dust intrusion.Piezoelectric ceramic is fixed on the top of the metal box inside the body.Base fixed in the open end of box, and covered with resin.Of ultrasonic sensors for industrial robots, the requirements to achieve an accuracy of 1mm, and has strong ultrasonic ponents using conventional bimorph bending vibration of the vibrator, in the case of frequencies above 70kHz, it is impossible to achieve this purpose.Therefore, in the high-frequency probe, you must use the vertical thickness vibration mode piezoelectric ceramic.In this case, the acoustic impedance of piezoelectric ceramics and the air becomes very important match.Acoustic impedance of piezoelectric ceramic 2.6 × 107kg/m2s, while the acoustic impedance of air is 4.3×102kg/m2s.5different power piezoelectric vibration will result in substantial losses of radiation on the surface.Adhesion of a special material on the piezoelectric ceramic, matching layers, as the sound can be achieved with air impedance match.This structure allows up to several hundred kHz ultrasonic sensors in the frequency of the circumstances, still be able to work properly.Ultrasonic distance sensor technology and application of the principle:Ultrasonic distance sensor can be widely used in Level (level) monitoring, robot collision avoidance, a variety of ultrasonic proximity switches, and related areas such as anti-theft alarm, reliable, easy installation, waterproof, small launch angle, high sensitivity,display instruments to facilitate connections with industry, also provides a larger probe launch angle.1, ultrasonic range finder: ultra-high energy acoustic ranging techniques to ultrasonic distance measurement techniques have been major breakthroughs, it not only broadens the applications of ultrasonic distance measurement technology (for very poor working conditions), and the use of smart regulation technology,greatly improve the reliability of ultrasonic products, and performance indicators, allowing users to worry about without looking back.Excellent echo processing technology ,5-50KHZ of ultra high strength level meter wave frequency to the maximum range up to 120 meters for medium temperature is -20℃-+175℃.Intelligent automatic adjustment made wave frequency, automatic temperature compensation function to work more stable and reliable.HpAWK series also has a flexible work (the power supply for 12VDC, 24VDC, 110V AC, 220V AC; two / three / four-wire system can be freely combined in the same instrument.It also has advanced remote GSM, CDMA, Internet debugging features, enabling users to readily available technical support.中文译文:超声波距离传感器设计原理:超声波传感器是利用超声波的特性研制而成的传感器。
超声波测距仪(实时显示声光报警)毕业设计论文报告摘要机器人通过其感知系统觉察前方障碍物距离和周围环境来实现绕障、自动寻线、测距等功能。
超声波测距相对其他测距技术而言成本低廉,测量精度较高,不受环境的限制,应用方便,将它与红外传感器等结合共同实现机器人寻线和绕障功能。
本文介绍了基于STC89C51的超声波测距系统,阐述了超声波测距系统的硬件设计、软件设计及其工作原理。
该设计主要由单片机控制模块、数码管显示模块、DS18B20温度补偿模块以及声光报警模块等构成。
利用超声波的反射原理,计算超声波在空气中的传播时间的一半再乘以经过温度补偿修正后的速度就可以得出障碍物到传感器之间的距离,并在数码管显示出来。
同时,该系统在测量距离小于10cm时能进行声光报警。
该系统具有硬件电路简单、成本低、工作可靠、功耗低、体积小、误差小、有良好的测量精度等优点。
目前,超声波清洗技术、雷达技术等在医学、军事上占据着重要地位,因此研究超声波技术具有一定的研究意义。
本设计作品基本满足设计的要求,有一定的推广性,同时针对不足,如测量距离过小等,文章在最后提出了一些改进性能的可行性方案。
关键字:单片机;传感器;超声波测距;温度补偿Abstractrobot through its perception system to detect obstacles that in front of the road and the surrounding environment to achieve the distance around the barrier, auto hunt, range and other functions.Ultrasonic Ranging in terms to other ranging technology is low-cost, high accuracy, without environmental constraints, and convenient, it will be combined together with infrared sensors achieve robot hunt around the barrier function.This article describes the ultrasonic ranging system based on STC89C51,which e laborate ultrasonic Ranging System hardware design, software design and its working principle.The design is mainly controlled by the microcontroller module,LED display module, DS18B20 temperature compensation module, as well as sound and light alarm module ing the principle of reflection of the ultrasonic wave,Calculate the ultrasonic propagation time in the air in half and then multiplied by the speed after the correction of the temperature compensation that can be drawn between the obstacle to the sensor distance,And digital display.Secondly, the sound and light alarm when the system measuring distance less than 10cm .The system has an Advantage of Simple hardware circuit, low cost, reliable, low power consumption, small size, the error is small, h ave a good measurement accuracy, etc..At present, the ultrasonic cleaning technology, radar technology in medicine, the military occupies an important position,so the research ultrasound technology has a certain significance. This design works basically meet the design requirements, there are certain promotional, while for deficiencies, such as measuring the distance is too small, etc., the article concludes with a number of improvements in the performance of the feasibility of the program.KeyWords:MCU;Sensor;Ultrasonic Ranging;Temperature compensation目录摘要 0Abstract (1)第一章绪论 (4)1.1课题的研究背景 (4)1.2超声波在国内外的发展现状 (6)1.3研究目的和意义 (6)1.4研究内容 (6)1.5 论文结构 (7)第二章系统方案设计 (8)2.1设计要求 (8)2.2设计方案 (8)第三章硬件设计 (10)3.1 AT89C51单片机简介 (10)3.1.1 AT89C51各引脚的含义和功能 (11)3.2系统硬件设计组成部分 (13)3.2.1 AT89C51单片机最小系统 (13)3.2.2 数码管显示模块 (13)3.2.3超声波发射接收模块 (14)3.2.4声光报警模块 (20)3.2.5复位电路 (20)3.2.6 DS18B20温度补偿电路 (22)3.2.6.1 DS18B20内部结构及测温原理 (23)3.2.6.2 DS18B20的封装形式及引脚功能 (24)3.2.6.3 DS18B20的供电方式 (25)3.2.7 +5V电源模块 (26)第四章软件设计 (27)4.1软件整体设计 (28)4.2系统主要模块程序设计 (29)4.2.1超声波发射程序及接收中断子程序 (29)4.2.2 DS18B20访问程序 (29)第五章调试与检测 (31)5.1硬件测试 (31)5.2 软件测试 (32)5.3结果分析 (32)5.4误差来源 (32)5.5 解决方案 (33)5.6本设计所做工作 (33)总结与展望 (35)谢词 (36)参考文献 (36)附录1 电路原理图及PCB图 (38)附录2 程序清单 (40)第一章绪论超声波以其指向性好、穿透能力强、能量消耗缓慢、环境污染小等优点,因而超声波常用于距离测量。
毕业设计(论文)外文资料翻译系(院):电子与电气工程学院专业:电气工程及其自动化姓名:学号:外文出处:United States Patent 5442592(用外文写)附件: 1.外文资料翻译译文;2.外文原文。
指导教师评语:签名:(手写签名)年月日注:请将该封面与附件装订成册。
外文资料翻译译文超声波测距仪文件类型和数目:美国专利5442592摘要:提出了一种可以抵消温度的影响和湿度的变化的新型超声波测距仪,包括测量单元和参考资料。
在每一个单位,重复的一系列脉冲的产生,每有一个重复率,直接关系到各自之间的距离,发射机和接收机。
该脉冲序列提供给各自的计数器,计数器的产出的比率,是用来确定被测量的距离。
出版日期:1995年8月15日主审查员:罗保.伊恩j.一、背景发明本发明涉及到仪器的测量距离,最主要的是,这种仪器,其中两点之间传输超声波。
精密机床必须校准。
在过去,这已经利用机械设备来完成,如卡钳,微米尺等。
不过,使用这种装置并不利于本身的自动化技术发展。
据了解,两点之间的距离可以通过测量两点之间的行波传播时间的决定。
这样的一个波浪型是一种超声波,或声波。
当超声波在两点之间通过时,两点之间的距离可以由波的速度乘以测量得到的在分离的两点中波中转的时间。
因此,本发明提供仪器利用超声波来精确测量两点之间的距离对象。
当任意两点之间的介质是空气时,声音的速度取决于温度和空气的相对湿度。
因此,它是进一步的研究对象,本次的发明,提供的是独立于温度和湿度的变化的新型仪器。
二、综述发明这项距离测量仪器发明是根据上述的一些条件和额外的一些基础原则完成的,其中包括一个参考单位和测量单位。
参考和测量单位是相同的,每个包括一个超声波发射机和一个接收机。
间隔发射器和接收器的参考值是一个固定的参考距离,而间距之间的发射机和接收机的测量单位是有最小距离来衡量的。
在每一个单位,发射器和接收器耦合的一个反馈回路,它会导致发射器产生超声脉冲,这是由接收器和接收到一个电脉冲然后被反馈到发射机转换,从而使重复系列脉冲的结果。
重复率脉冲是成反比关系之间的距离发射器和接收器。
在每一个单位,脉冲提供一个反馈。
由于参考的距离是众所周知的声速,比例反产出是利用数学以确定所期望的距离来衡量。
由于这两方面都是相同的影响,温度和湿度的变化,采取的比例相同,由此产生的测量变得准确。
三、详细说明一超声波测距原理1、压电式超声波发生器原理压电式超声波发生器实际上是利用压电晶体的谐振来工作的。
超声波发生器内部结构如下所示,它有两个压电晶片和一个共振板。
当它的两极外加脉冲信号,其频率等于压电晶片的固有振荡频率时,压电晶片将会发生共振,并带动共振板振动,便产生超声波。
反之,如果两电极间未外加电压,当共振板接收到超声波时,将压迫压电晶片作振动,将机械能转换为电信号,这时它就成为超声波接收器了。
2、超声波测距原理超声波发射器向某一方向发射超声波,在发射时刻的同时开始计时,超声波在空气中传播,途中碰到障碍物就立即返回来,超声波接收器收到反射波就立即停止计时。
超声波在空气中的传播速度为340m/s,根据计时器记录的时间t,就可以计算出发射点距障碍物的距离(s),即:s=340t/2二超声波测距系统的电路设计系统的特点是利用单片机控制超声波的发射和对超声波自发射至接收往返时间的计时,单片机选用8751,经济易用,且片内有4K的ROM,便于编程。
电路原理图如图2所示。
其中只画出前方测距电路的接线图,左侧和右侧测距电路与前方测距电路相同,故省略之。
1、40kHz 脉冲的产生与超声波发射测距系统中的超声波传感器采用UCM40的压电陶瓷传感器,它的工作电压是40kHz的脉冲信号,这由单片机执行下面程序来产生。
puzel:mov 14h, #12h;超声波发射持续200mshere:cpl p1.0 ;输出40kHz方波nop ;nop ;nop ;djnz 14h,here;ret前方测距电路的输入端接单片机P1.0端口,单片机执行上面的程序后,在P1.0 端口输出一个40kHz的脉冲信号,经过三极管T放大,驱动超声波发射头UCM40T,发出40kHz的脉冲超声波,且持续发射200ms。
右侧和左侧测距电路的输入端分别接P1.1和P1.2端口,工作原理与前方测距电路相同。
2、超声波的接收与处理接收头采用与发射头配对的UCM40R,将超声波调制脉冲变为交变电压信号,经运算放大器IC1A和IC1B两极放大后加至IC2。
IC2是带有锁定环的音频译码集成块LM567,内部的压控振荡器的中心频率f0=1/1.1R8C3,电容C4决定其锁定带宽。
调节R8在发射的载频上,则LM567 输入信号大于25mV,输出端8脚由高电平跃变为低电平,作为中断请求信号,送至单片机处理。
前方测距电路的输出端接单片机INT0端口,中断优先级最高,左、右测距电路的输出通过与门IC3A的输出接单片机INT1端口,同时单片机P1.3和P1.4接到IC3A的输入端,中断源的识别由程序查询来处理,中断优先级为先右后左。
部分源程序如下:receive1:push pswpush accclr ex1 ;关外部中断1jnb p1.1, right ;P1.1引脚为0,转至右测距电路中断服务程序jnb p1.2, left ;P1.2引脚为0,转至左测距电路中断服务程序return:SETB EX1;开外部中断1pop? accpop? pswretiright:...? ;右测距电路中断服务程序入口? ajmp? returnleft:... ;左测距电路中断服务程序入口? ajmp? return3、计算超声波传播时间在启动发射电路的同时启动单片机内部的定时器T0,利用定时器的计数功能记录超声波发射的时间和收到反射波的时间。
当收到超声波反射波时,接收电路输出端产生一个负跳变,在INT0或INT1端产生一个中断请求信号,单片机响应外部中断请求,执行外部中断服务子程序,读取时间差,计算距离。
其部分源程序如下:RECEIVE0:PUSH PSWPUSH ACCCLR EX0 ;关外部中断0? MOV R7, TH0 ;读取时间值MOV R6, TL0?CLR CMOV A, R6SUBB A, #0BBH;计算时间差MOV 31H, A ;存储结果MOV A, R7SUBB A, #3CHMOV 30H, A?SETB EX0 ;开外部中断0POP ACC?POP PSWRETI四、超声波测距系统的软件设计软件分为两部分,主程序和中断服务程序,如图3(a)(b)(c) 所示。
主程序完成初始化工作、各路超声波发射和接收顺序的控制。
定时中断服务子程序完成三方向超声波的轮流发射,外部中断服务子程序主要完成时间值的读取、距离计算、结果的输出等工作。
五、结论对所要求测量范围30cm~200cm内的平面物体做了多次测量发现,其最大误差为0.5cm,且重复性好。
可见基于单片机设计的超声波测距系统具有硬件结构简单、工作可靠、测量误差小等特点。
因此,它不仅可用于移动机器人,还可用在其它检测系统中。
思考:至于为什么接收不用晶体管做放大电路呢,因为放大倍数搞不好,CX20106集成放大电路,还带自动电平增益控制,放大倍数为76dB,中心频率是38k到40k,刚好是超声波传感器的谐振频率。
2:外文原文(复印件)Ultrasonic distance meterDocument Type and Number:United States Patent 5442592 Abstract:An ultrasonic distance meter cancels out the effects of temperature and 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 are provided to respective counters, and the ratio of the counter outputs is utilized to determine the distance being measured.Publication Date:08/15/1995Primary Examiner:Lobo, Ian J.A.BACKGROUND OF THE INVENTIONThis invention relates to apparatus for the measurement of distance and, more particularly, to such apparatus which transmits ultrasonic waves between 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 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 time 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 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.B.SUMMARY OF THE INVENTIONThe foregoing and additional 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. 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 which 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 the 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 variations, by taking the ratio of the counts, the resultant measurement becomes insensitive to such variations. C.DETAILED DESCRIPTIONA.principle of ultrasonic distance measurement1, the principle of piezoelectric ultrasonic generatorPiezoelectric 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 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 of piezoelectric chip, the mechanical 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, 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), that is: s = 340t / 2B.Ultrasonic Ranging System for the Second Circuit 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 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.1,40 kHz ultrasonic pulse generated with the launchRanging 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 generate.puzel: mov 14h, # 12h; ultrasonic firing continued 200mshere: cpl p1.0; output 40kHz square wavenop;nop;nop;djnz 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 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.2, reception and processing of ultrasonicUsed 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 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 the 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:receive1: push pswpush accclr ex1; related external interrupt 1jnb p1.1, right; P1.1 pin to 0, ranging from right to interrupt service routine circuitjnb p1.2, left; P1.2 pin to 0, to the left ranging circuit interrupt service routinereturn: SETB EX1; open external interrupt 1pop? accpop? pswretiright: ...?; 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 circuitry within the timerT0, 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 code is as follows:RECEIVE0: PUSH PSWPUSH ACCCLR EX0; related external interrupt 0? MOV R7, TH0; read the time valueMOV R6, TL0?CLR CMOV A, R6SUBB A, # 0BBH; calculate the time differenceMOV 31H, A; storage resultsMOV A, R7SUBB A, # 3CHMOV 30H, A?SETB EX0; open external interrupt 0POP ACC?POP PSWRETID.Fourth, the ultrasonic ranging system software designSoftware 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, 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 main external interrupt service subroutine to read the value of completion time, distance calculation, the results of the output and so on.E. 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 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, 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。