Development Of Three-dimensional Black Phosphorus Sensitive Film Microstructure Gas Sensor

For precision instruments,noise interference in the working environment is a major factor that affects the measurement results.The use of filters to process the measurement signal is a common method to reduce noise interference.This subject uses the adaptive filter of the noise cancellation structure to process the PSD signal in the laser three-dimensional small angle measuring instrument through the research on the related algorithm and structure of the adaptive filter.And this subject has studied the filtering effect of adaptive filter on PSD signal through experiment comparison.The optical self-collimation principle developed by using the collimation characteristics of laser has unique advantages in measuring small angles.Based on this principle,our research group designed a three-dimensional laser small angle measuring instrument using PSD sensor as the receiver of the optical path.The instrument can accurately monitor the displacement of the light spot to calculate the angular offset according to the corresponding geometric relationship.However,the system is susceptible to interferen ce from the external environment,and noise or temperature changes in the external environment will affect the accuracy of the measurement results.Therefore,this design proposes to use the principle of adaptive filter to filter the PSD signal.Compared with traditional filters,adaptive filters do not require prior knowledge of the statistical characteristics of the research object,and can automatically adjust their own parameters following changes in the external environment to achieve the best filtering and can effectively reduce the influence of external environmental noise interference on the measurement results of the instrument.This design studies the relevant theories of adaptive filters.Among the existing adaptive filtering algorithms,a better-performing and easy-to-implement LMS(Least Mean Square)algorithm is selected for the design of adaptive filters,And use MATLAB software to simulate the filtering effect of LMS adaptive filtering algorithm.In this design,STM32F103 ZE microcontroller is selected as the embedded processor chip of the 3D laser small angle measuring instrument,and the design of the adaptive filter is realized by the software program.On the basis of the preliminary processing of the PSD signal by the hardware circuit,an adaptive filter is used to further filter the PSD signal,and finally the effect of the adaptive filter is verified through the stability experiment of the indication.After comparing the experimental results with different filtering algorithms,it is found that after filtering the PSD signal with an adaptive filter,the stability of the indication of the small angle measuring instrument is improved,which greatly improves the measurement accuracy of the instrument.