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毕业设计

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DZ147基于AT89C51单片机倒车防撞报警系统设计,毕业设计

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Ultrasonic wave examination development summary The high velocity, the high efficiency is the modern industry symbol, but this is the establishment above the high grade foundation. The design and the craft personnel should understand that,Must a organizational structure, stochastically has microscopically, the macroscopic flaw, may sometimes even be frequently only can depend upon not damages the examination technology the utilization only then to give to discover, appraisal. Certainly, this with dozens of year in every way value and the general jobholders difficult endeavor, causes not to damage the examination technology to have certain ability in this aspect to concern. Now, in the industry developed country, not damages the examination in the product design, the development, the user departments already by the fruitful utilization, in 1981 American former president Reagan in not damaged the examination academic society 40th anniversary congress to US in the letter of congratulations to say: “You can give the airplane and the spatial flight vehicle, the power plant, the ships, the automobile and the building and so on bring a greater degree the reliability. Not has not damaged the examination, we not impossible to enjoy at present in these domains and other domain leading status.”Not damages the examination by the swift and violent potential to the depth development, the objective need is after all the biggest power which one specialty may develop. Our country not damages the examination technology is grows out of nothing, develops gradually from the lower stage to the application popular present stage level. Ultrasonic wave instrumentation development production, also presses this rule development change approximately. The 50s, our country starts from the overseas introduction ultrasonic wave instrument, many is the unwieldy electronic tubular instrument. If Englands UCT-2 ultrasonic wave instrumentation, reaches 24Kg again, various units do the experimental study work positively, has obtained the good effect in some project examination. At the end of the 50s at the beginning of 60s, the domestic scientific research unit imported Poland to produce the ultra acoustimeter, and carried on the imitation production. Afterwards, Shanghai Tongji University develops the CTS-10 nonmetallic supersonic instrumentation, also is the electron tubular, instrument heavy approximately 20Hg. This instrument performance is stable, the profile is clear. But at that time this kind of instrument only then the individual scientific research unit used, the construction work department used not not many. Until 70s intermediate stages, because not damaged the examination technology still to be at the experimental stage, the promotion has not popularized, therefore the instrument big development, still has not used the electronic tubular UCT-2,CTS-10. In 1976, after National Construction committee Office of Sciences managed holds the nation architectural engineering examination technology meeting, National Construction committee not damaged the concrete the examination technology to list as the key attack project, the organization nation 6 unit cooperation attack. Henceforth, not damages the examination technology to start to enter has the plan, has the goal research stage. Along with the electronics industry rapid ntsdevelopment, the transistor unit has replaced the electron tube component gradually, is more advantageous to not damages the examination technology the promoted popularization. If the Romanian N2701 ultrasonic wave reflectoscope reflector, is composed by the transistor discrete component, has the profile and the numerical code demonstrated, instrument weight 10Kg. The 70s, English C.N.S Corporation promotes only has the 3.5Kg heavy PUNDIT portable ultra acoustimeter. In October, 1978, Chinese Construction Academy of science developed JC-2 portable ultrasonic wave instrumentation. This instrument uses the TTL line, the numerical code demonstrated that, the instrument weight is 5Kg. Develops same time the supersonic instrumentation also has SC-2, CTS-25, SYC-2 ultrasonic wave instrumentation. Henceforth, our country had the ultrasonic wave instrument which own produce, not damaged the examination technology for the promoted application to lay the good foundation. The ultrasonic wave examination technology is our country prioritize and the promoted new technology, it has the high accuracy, not damages, merits and so on non-contact. At present, already widely applied at the machine manufacture, the electronic metallurgy, the navigation, the astronavigation, the petroleum chemical industry, industry domains and so on transportation. In addition, in the materials science, the medicine, domains and so on in biological science also occupies has the important status. Overseas was enhancing the ultrasonic ranging aspect to do the massive research, the domestic some scholars have also done the correlation research. Mainly is decided to the ultrasonic ranging precision by the ultrasonic propagation time and the ultrasonic wave which measured in the medium propagation velocity, in the two the propagation time precision influence is big, therefore the majority of literature use reduce the propagation time the uncertainty to increase the range finder precision. At present, the phase survey law and the sound spectrum outline analytic method or the two unify the method is main reduces the survey transmission uncertainty the method. The ultrasonic wave examination technology took not damages one of examination technology important methods, is playing the vital role in its developing process, it has provided the appraisal solid state material microscopic organization and the correlation mechanics performance, examines its microscopic and the macroscopic discontinous effective general method. As a result of its signal high-frequency response, the ultrasonic wave examination early time only uses the simulation quantity signal the analysis, the majority of check-out facility only has the A scanning form, needs through experienced not to damage examines the personnel to carry on the artificial analysis to the signal to be able to draw the correct conclusion, to examines is high with analysis staffs request, therefore, the human factor is big to the examination result influence, the profile not easy to record and the preservation, is not suitable completes the automated examination. The 80s later periods, as a result of the computer technology and the high speed component unceasing development, make the ultrasonic wave signal the digitization to gather and possibly to analyze into. At present domestic also one after another appeared each kind of digitized ultrasonic wave check-out facility, and has become the ultrasonic wave examination the development direction. Xiamen Universitys some scholar has studied one echo outline analytic method. This method seeks the echo enveloping curve in the range finder through two surveys to obtain the echo beginning, after like this processed the ultrasonic propagation time precision to obtain the very big enhancement. Italys Carullo et al. introduced one kind of self-adaptive system, uses the ntsspecial launch profile to obtain the good echo envelope, simultaneously uses to the ambient noise carries on the estimation, establishes certain echo Kaiping electric circuit, also uses the automatic gain the control amplifier, enhances the ultrasonic wave through these measures the survey precision. Moreover, also has the massive literature research to use the digital signal processing technology and the wavelet transformation theory enhances the transmission time the precision. These processing method has all obtained the good effect. At present domestic and foreign all turns towards the digitized direction in the ultrasonic wave examination domain to develop, the digital ultrasonic wave instrumentation development speed is very quick. The home also one after another appeared many digital ultrasonic wave instruments and the analysis system in recent years. On international takes extremely to the ultrasonic wave examination digitization technology research, the overseas production similar product and the research company has USs Pan-America (PANAMETRICS) Corporation, METEC Corporation, Canadas R/D TECH Corporation, Germanys K-K Corporation, Frances SOFRATEST Corporation and Spains TECNATOM Corporation and so on, the above these companies produce ultrasonic wave examination gathering, the analysis and the image formation processing system technical level is high, is in the leading level in the world. Along with examination engineering research unceasingly thorough, is more and more high to the supersonic instrumentation function request, the single numerical code demonstrated the supersonic examination instrumental measurement reads can bring the big test error. Further requests the ultra acoustimeter which later will produce to be able to have double reveals and the inner tube has the single trigger micro processing function. Afterwards has the examination, the record, the memory, the data processing and the analysis and so on many function intellectualized examination analyzer develops one after another successfully. The ultra acoustimeter development presents a prosperous scene. Among them, the coal academy of science develops 2000A supersonic analysis instrumentation, is one kind of inner tube microprocessor intellectualization metering equipment, operates completely all is in the microprocessor under the control management, all observed values, the processing result, the condition information all demonstrated on the teletron, and may meet the miniature printer printing. Its numeral and the profile quite are all clear stably, the operation is simple, the reliability is high, has the power failure memory function, its serial port may facilitate the user to carry on the post-processing and the related procedure development to the instrument test data. Compares with the domestic similar product, design novel reasonable, the function is complete, has the significant breakthrough and the innovation in the instrument design, has achieved the international advanced level. At present, the computer market price large scale drop, uses the non-integrated ultrasonic wave instrumentation, the computer may display an it machine multipurpose each kind of function, in fact is biggest economy. In the past that kind of entire function instrument establishment, the might as well independent ultra acoustimeter, the computer might display respective characteristic fully. The high intellectualization instrumentation only can satisfy the examination condition, the use environment, the duplicated test content and so on the basic situation is same, only then may display its unique function fully. The instrument design also should embark from the actual situation, can satisfy the user the request. In summary, our country ultrasonic wave instrument development and the production, has develops greatly, some models have surpassed the overseas similar instrument nts 超声波检测发展综述 高速度，高效率是现代工业的标志，而这是建立在高质量的基础之上的。设计和工艺人员理应了解：非均一的组织结构，随机出现的微观，宏观缺陷，常常可以有时甚至是只能依靠无损检测技术的运用方可予以发现，评价。当然，这与数十年来多方的重视和广大从业人员的艰辛努力，使无损检测技术在这方面已具有一定的能力有关。现在，在工业发达国家，无损检测在产品的设计，研制，使用部门已被卓有成效的运用， 1981 年美国前总统里根在给美国无损检测学会成立 40 周年大会的贺信中就说过：“你们能够给飞机和空间飞行器，发电 厂，船舶，汽车和建筑物等带来更大程度的可靠性。没有无损检测，我们就不可能享有目前在这些领域和其他领域的领先地位。”无损检测正在以迅猛之势向纵深发展，客观的需要毕竟是一种专业可以发展的最大动力。 我国无损检测技术是从无到有，从低级阶段逐渐发展到应用普及的现阶段水平。超声波检测仪器的研制生产，也大致按此规律发展变化。 五十年代，我国开始从国外引进超声波仪器，多是笨重的电子管式仪器。如英国的 UCT-2 超声波检测仪，重达 24Kg，各单位积极开展试验研究工作，在一些工程检测中取得了较好的效果。 五十年代末六十年 代初，国内科研单位进口了波兰产超声仪，并进行仿制生产。随后，上海同济大学研制出 CTS-10 型非金属超声检测仪，也是电子管式，仪器重约 20Hg。该仪器性能稳定，波形清晰。但当时这种仪器只有个别科研单位使用，建工部门使用不多。直至七十年代中期，因无损检测技术仍处于试验阶段，未推广普及，所以仪器没有多大发展，仍使用电子管式的 UCT-2， CTS-10 型仪器。 1976 年，国家建委科技司主持召开全国建筑工程检测技术交流会后，国家建委将混凝土无损检测技术列为重点攻关项目，组织全国 6 个单位协作攻关。从此，无 损检测技术开始进入有计划，有目的的研究阶段。随着电子工业的飞速发展，半导体元件逐渐代替了电子管器件，更有利于无损检测技术的推广普及。如罗马尼亚 N2701 型超声波测试仪，是由晶体管分立元件组成，具有波形和数码显示，仪器重量 10Kg。七十年代，英国 C.N.S 公司推出仅有 3.5Kg 重的 PUNDIT 便携式超声仪。 1978 年 10 月，中国建筑科学院研制出 JC-2 型便携式超声波检测仪。该仪器采用 TTL 线路，数码显示，仪器重量为 5Kg。同期研制出的超声检测仪器还有 SC-2 型， CTS-25 型， SYC-2 型超声波检测仪。从此，我国有了自己生产的超声波仪器，为推广应用无损检测技术奠定了良好的基础。 超声波检测技术是我国重点发展和推广的新技术，其具有高精度，无损，非接触等优点。目前，已经广泛地应用在机械制造，电子冶金，航海，宇航，石油化工，交通等工业领域。此外，在材料科学，医学，生物科学等领域中也占具重要地位。国外在提高超声波测距方面做了大量研究，国内一些学者也做了相关研究。对超声波测距精度主要取决于所测的超声波传播时间和超声波在介质中的传播速度，二者中以传播时间的精度影响较大，所以大部分文 献采用降低传播时间nts的不确定度来提高测距精度。目前，相位探测法和声谱轮廓分析法或二