本文選題：風(fēng)速風(fēng)向儀 + 超聲　； 參考：《電子科技大學(xué)》2014年碩士論文

【摘要】：介紹了風(fēng)速風(fēng)向儀的幾種實(shí)現(xiàn)方式,對(duì)采用超聲來實(shí)現(xiàn)風(fēng)速測(cè)量的幾種方法的原理、各自的優(yōu)缺點(diǎn),以及影響測(cè)量精度因素進(jìn)行了討論,并對(duì)超聲風(fēng)速風(fēng)向儀國內(nèi)外的國內(nèi)外研究現(xiàn)狀做了介紹。分別從超聲換能的諧振頻率與到達(dá)時(shí)間測(cè)量準(zhǔn)確度、超聲傳播衰減特性、發(fā)射信號(hào)指向性等幾個(gè)參數(shù)的關(guān)系的角度進(jìn)行了分析,選擇了適合的工作頻率。對(duì)換能器結(jié)構(gòu)、換能器的壓電材料、聲阻抗匹配層設(shè)計(jì)、背襯材料、工藝流程等進(jìn)行了討論。分析了兩種類型超聲換能器的設(shè)計(jì)方法:第一種是工作在徑向振動(dòng)模式來實(shí)現(xiàn)的單頻壓電超聲換能器;第二種是利用壓電材料柱體的徑向和縱向振動(dòng)模態(tài)接近,通過兩種模態(tài)耦合來形成的寬帶換能器。多換能器組的空間拓?fù)浣Y(jié)構(gòu)對(duì)矢量風(fēng)速的測(cè)量準(zhǔn)確度有重要影響,本文對(duì)直通式和反射式兩種結(jié)構(gòu)分別進(jìn)行了分析,提出了一種兩者相結(jié)合的超聲探頭拓?fù)浣Y(jié)構(gòu),并采用計(jì)算流體動(dòng)力學(xué)技術(shù)對(duì)其進(jìn)行了仿真分析,拓展了單個(gè)超聲探頭的風(fēng)速測(cè)量范圍。文中利用FPGA內(nèi)部的鎖相環(huán)設(shè)計(jì)了激勵(lì)調(diào)制信號(hào)產(chǎn)生電路,驅(qū)動(dòng)電路采用MOSFET電路實(shí)現(xiàn)。接收端的超聲探頭輸出的探測(cè)信號(hào)幅度非常小,包含大量因聲學(xué)干擾和電學(xué)干擾引起的噪聲信號(hào),本文設(shè)計(jì)了一種多級(jí)放大、濾波結(jié)構(gòu),放大信號(hào)的同時(shí)很好地抑制了噪聲信號(hào)。放大后的模擬信號(hào)被數(shù)模轉(zhuǎn)換電路轉(zhuǎn)換成數(shù)字信號(hào),并送入FPGA進(jìn)行處理。文章采用硬件編程語言,實(shí)現(xiàn)了超聲信號(hào)傳播時(shí)間測(cè)量,討論并比較了過零檢測(cè)法、相位檢測(cè)法和相關(guān)檢測(cè)法等三種超聲信號(hào)到達(dá)時(shí)間測(cè)量方法。本文完成了一種二維超聲風(fēng)速風(fēng)向儀設(shè)計(jì),通過采用直通式與反射式相結(jié)合的超聲探頭,使風(fēng)速儀在0~150m/s風(fēng)速范圍內(nèi)的測(cè)量準(zhǔn)確度優(yōu)5%。
[Abstract]:Several methods of wind speed wind instrument are introduced. The principle of several methods for measuring wind speed by ultrasonic wave, their advantages and disadvantages, and factors affecting the measurement accuracy are discussed. The current research situation at home and abroad at home and abroad of the ultrasonic wind speed wind instrument is introduced. The resonance frequency and the arrival time of the ultrasonic energy exchange are measured respectively. The relationship between the quantity accuracy, the attenuation characteristic of ultrasonic propagation and the directivity of the transmitting signal is analyzed, and the suitable working frequency is selected. The structure of the transducer, the piezoelectric material of the transducer, the design of the acoustic impedance matching layer, the backing material and the process flow are discussed. The design of the two types of ultrasonic transducer is analyzed. Method: the first one is a single frequency piezoelectric ultrasonic transducer that works in the radial vibration mode. The second kind is the broadband transducer using the radial and longitudinal vibration modes of the piezoelectric material column and the coupling of the two modes. The spatial topology of the multi transducer group has an important influence on the measurement accuracy of the vector wind speed. In this paper, the two structures of direct and reflective types are analyzed, and a combination of ultrasonic probe topology is proposed. The simulation analysis is carried out by using computational fluid dynamics technology to expand the velocity measurement range of a single ultrasonic probe. In this paper, the excitation modulation signal is designed by using the phase-locked loop in FPGA. The circuit, the drive circuit is realized by the MOSFET circuit. The amplitude of the detection signal output by the receiver is very small. It contains a large number of noise signals caused by acoustic interference and electrical interference. In this paper, a multistage amplification, filter structure, magnified signal are designed and the noise signal is suppressed well. The analog signal after amplification is counted. The mode conversion circuit is converted into a digital signal and sent to FPGA for processing. In this paper, we use the hardware programming language to realize the measurement of the transmission time of ultrasonic signals, discuss and compare three methods of measuring the time of arrival of ultrasonic signals, such as zero crossing detection, phase detection and correlation detection. This paper has completed a two-dimensional ultrasonic wind speed wind direction instrument. The accuracy of the anemometer in the range of 0~150m/s wind speed is 5%.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TB552

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本文編號(hào)：2117530