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Design And Research Of Dynamic Microcantilever Array Sensors

Posted on:2020-08-08Degree:MasterType:Thesis
Country:ChinaCandidate:F ZhangFull Text:PDF
GTID:2428330572496843Subject:Circuits and Systems
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As a high-performance sensor,dynamic microcantilever sensor has been widely studied and applied.The main purpose of this paper is to design and build a dynamic microcantilever array sensors and use it to detect tiny mass and nitrogen flow rate.The microcantilever array is driven by an external and independent piezoelectric actuator to resonate the microcantilever array.This type of drive does not require a special microcantilever,and the drive capability and size of the external piezo driver can be selected as needed.In this paper,the microcantilever sensing signal is detected by optical method,and only one laser is used to scan the microcantilever array.This method can overcome the problem that the laser intensity or spot size of the free end of each microcantilever is inconsistent when multiple lasers are irradiated to the microcantilever array.The deflection signal of the free end of the microcantilever is amplified by the principle of optical lever,and the optical signal reflected by the microcantilever is received by the position sensitive detector.The position sensitive detector is susceptible to ambient light,so the shading shell is added outside the sensor,and a filtering procedure is added in the upper computer program to reduce the influence of ambient light on the experimental result.In the dynamic mode,in order to reduce the sampling frequency of the data acquisition module and reduce the complexity of the host computer program,only the position sensitive detector coordinate axis signal and the driving signal in parallel with the microcantilever are collected to reduce data acquisition.The required channel,which reduces the sampling frequency of the data acquisition module,and facilitates the writing and data analysis processing of the host computer program.The purpose of the acquisition of the driving signal is to replace the frequency of the microcantilever vibration signal by the driving signal frequency,and reduce the influence of environmental factors on the resonance frequency analysis of the microcantilever.In this paper,the upper computer program is written by graphical program editing software LabVIEW.The software has a rich signal analysis and processing module,which is convenient for programming and saves development time.In this paper,the dynamic microcantilever array sensors is used to detect the tiny mass in the dynamic mode,as well as the size and distribution of the nitrogen flow velocity in the dynamic mode and the static mode.The sensitivity of the tiny mass detection in dynamic mode is about 1.03Hz/pg,the minimum detectable nitrogen flow rate in static mode is about 2.24m/s,and the minimum detectable nitrogen flow rate in dynamic mode is about 0.32m/s.The dynamic mode detection result is better than static mode.The experimental results show that the resonant frequency of the microcantilever decreases with the increase of the mass of the free end,and increases with the increase of the gas velocity above the free end.When the microcantilever is closer to the nitrogen outlet,the resonance frequency increases and the greater the deflection displacement.In this paper,the feasibility of the constructed dynamic microcantilever array sensors as a tiny mass and gas flow rate detection platform is verified by experiments.Figure [57] table [1] reference [83]...
Keywords/Search Tags:microcantilever array, mass, flow rate, optical lever, resonant frequency
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