基于Havar合金膜片的電容式壓力傳感器研制
發(fā)布時(shí)間：2018-07-18 16:16
【摘要】：電容式壓力傳感器因其靈敏度高、溫阻效應(yīng)低以及工作穩(wěn)定性好,廣泛應(yīng)用于工業(yè)自動(dòng)化檢測與監(jiān)控場所。隨著工作環(huán)境的日益復(fù)雜及惡化,傳統(tǒng)的壓力傳感器顯現(xiàn)出很大的局限性。因此,提出了一種采用Havar合金為中心膜片的壓力傳感器,比傳統(tǒng)的不銹鋼膜片具有更高的強(qiáng)度和韌性,更優(yōu)異的抗腐蝕性及抗磁性。通過測量Havar膜片在外部壓力作用下的位置變化所產(chǎn)生的電容變化量,可實(shí)現(xiàn)小量程壓力的檢測。本文圍繞差壓電容式壓力傳感器的理論基礎(chǔ),制作工藝以及測試進(jìn)行深入研究與實(shí)現(xiàn)。中心膜片是電容式壓力傳感器的核心部分,其直接影響壓力傳感器的靈敏度及分辨率。文中應(yīng)用有限元分析軟件ANSYS WORKBENCH,對膜片的工作特性進(jìn)行理論分析,得到膜片的受力以及形變的二維分布。根據(jù)電容兩固定極板的間距及最大檢測壓力,計(jì)算出膜片厚度的最小允許值。通過構(gòu)建膜片中心點(diǎn)的形變與輸入壓力的特性曲線,先得到膜片靈敏度,再以此為目標(biāo)函數(shù),以膜片厚度和直徑為變量,優(yōu)化膜片的結(jié)構(gòu)參數(shù),最后采用Havar合金膜片的厚度50μm,直徑為Φ26mm。對電容式壓力傳感器的電容檢測電路進(jìn)行設(shè)計(jì),是基于靈敏度等關(guān)鍵技術(shù)指標(biāo)來完成的。采用了振蕩器、限幅器、鑒頻器和放大器等電路,其核心是C/F轉(zhuǎn)換和F/V轉(zhuǎn)換,將傳感器的弱電容信號轉(zhuǎn)換為電壓信號。通過對該電路進(jìn)行了模擬仿真試驗(yàn),得到較為接近的電壓輸出信號,驗(yàn)證了此電路能滿足電容檢測設(shè)計(jì)要求。同時(shí),對該電路進(jìn)行優(yōu)化設(shè)計(jì),從而提升了電路的檢測性能以及抗干擾能力。最后,確定電容式壓力傳感器的測試條件以及測試項(xiàng)目,對制作出的工程樣機(jī)進(jìn)行了測試,得到壓力傳感器的校準(zhǔn)數(shù)據(jù)。通過數(shù)據(jù)分析可以看到,測試結(jié)果與膜片的仿真結(jié)果較為接近,驗(yàn)證了基于Havar合金膜片的電容式壓力傳感器檢測壓力模型的準(zhǔn)確性。
[Abstract]:Capacitive pressure sensor is widely used in industrial automatic detection and monitoring because of its high sensitivity, low temperature resistance and good working stability. With the increasing complexity and deterioration of the working environment, the traditional pressure sensors show great limitations. Therefore, a pressure sensor with Havar alloy as the central diaphragm is proposed, which has higher strength and toughness, better corrosion resistance and diamagnetism than the traditional stainless steel diaphragm. The small range pressure can be detected by measuring the capacitance change caused by the position change of Havar diaphragm under external pressure. In this paper, the theoretical basis, fabrication process and test of differential capacitance pressure sensor are studied and realized. Central diaphragm is the core part of capacitive pressure sensor, which directly affects the sensitivity and resolution of pressure sensor. In this paper, the finite element analysis software ANSYS WORKBENCH is used to analyze the working characteristics of the diaphragm theoretically, and the stress and the two-dimensional distribution of the deformation of the diaphragm are obtained. The minimum allowable value of diaphragm thickness is calculated according to the distance between two fixed electrode plates and the maximum detection pressure. By constructing the characteristic curves of deformation and input pressure at the central point of the diaphragm, the sensitivity of the diaphragm is obtained first, then the diaphragm sensitivity is obtained, and the thickness and diameter of the diaphragm are taken as variables to optimize the structural parameters of the diaphragm. The thickness of Havar alloy diaphragm is 50 渭 m and the diameter is 桅 26mm. The capacitance detection circuit of capacitive pressure sensor is designed based on the key technical indexes such as sensitivity. The oscillator, limiter, frequency discriminator and amplifier are used. The core of the circuit is C / F conversion and F / V conversion. The weak capacitance signal of the sensor is converted into voltage signal. Through the simulation and simulation of the circuit, a close voltage output signal is obtained, and it is verified that the circuit can meet the design requirements of capacitance detection. At the same time, the circuit is optimized to improve the detection performance and anti-interference ability of the circuit. Finally, the test conditions and test items of the capacitive pressure sensor are determined, and the calibration data of the pressure sensor are obtained by testing the engineering prototype. Through the data analysis, it can be seen that the test results are close to the simulation results of the diaphragm, which verifies the accuracy of the pressure detection model of capacitive pressure sensor based on Havar alloy diaphragm.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TP212
本文編號：2132458
[Abstract]:Capacitive pressure sensor is widely used in industrial automatic detection and monitoring because of its high sensitivity, low temperature resistance and good working stability. With the increasing complexity and deterioration of the working environment, the traditional pressure sensors show great limitations. Therefore, a pressure sensor with Havar alloy as the central diaphragm is proposed, which has higher strength and toughness, better corrosion resistance and diamagnetism than the traditional stainless steel diaphragm. The small range pressure can be detected by measuring the capacitance change caused by the position change of Havar diaphragm under external pressure. In this paper, the theoretical basis, fabrication process and test of differential capacitance pressure sensor are studied and realized. Central diaphragm is the core part of capacitive pressure sensor, which directly affects the sensitivity and resolution of pressure sensor. In this paper, the finite element analysis software ANSYS WORKBENCH is used to analyze the working characteristics of the diaphragm theoretically, and the stress and the two-dimensional distribution of the deformation of the diaphragm are obtained. The minimum allowable value of diaphragm thickness is calculated according to the distance between two fixed electrode plates and the maximum detection pressure. By constructing the characteristic curves of deformation and input pressure at the central point of the diaphragm, the sensitivity of the diaphragm is obtained first, then the diaphragm sensitivity is obtained, and the thickness and diameter of the diaphragm are taken as variables to optimize the structural parameters of the diaphragm. The thickness of Havar alloy diaphragm is 50 渭 m and the diameter is 桅 26mm. The capacitance detection circuit of capacitive pressure sensor is designed based on the key technical indexes such as sensitivity. The oscillator, limiter, frequency discriminator and amplifier are used. The core of the circuit is C / F conversion and F / V conversion. The weak capacitance signal of the sensor is converted into voltage signal. Through the simulation and simulation of the circuit, a close voltage output signal is obtained, and it is verified that the circuit can meet the design requirements of capacitance detection. At the same time, the circuit is optimized to improve the detection performance and anti-interference ability of the circuit. Finally, the test conditions and test items of the capacitive pressure sensor are determined, and the calibration data of the pressure sensor are obtained by testing the engineering prototype. Through the data analysis, it can be seen that the test results are close to the simulation results of the diaphragm, which verifies the accuracy of the pressure detection model of capacitive pressure sensor based on Havar alloy diaphragm.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TP212
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