Research And Design Of Performance Test System For MEMS Capacitive Pressure Sensor

With the support of MEMS in laboratory,capacitive pressure sensors are of high sensitivity,good stability and easy integration,based on which the application of MEMS pressure sensors extents constantly.Currently,the MEMS pressure sensors testing system is featured with complicated structure,intricate testing technology,high price of micro-test instrument,high cost,insufficient compensation in the testing process for hardware compensation method and drift hardware for compensating circuit.In the practical production of sensors,only the real data can verify the quality of MEMS capacitive pressure sensor,which means the quality testing of MEMS capacitive pressure sensor is necessary.In this way,it has theoretical and practical significance to design a MEMS capacitive pressure sensor with the function of delivery pressure,testing,data collection,analysis and display.The paper aims at studying and design the performance of MEMS capacitive pressure sensor.Based on studying relative theories of MEMS capacitive pressure sensor,the author will definite the key technical problem of MEMS capacitive pressure sensors,analyse generation,control and regulation of gas pressure and detection,transformation and processing of sensors'output signal combining the research status of micro pressure sensors testing system.With the STM32F103RCT6as kernel controller,the air pump and electric proportional valve as pressure delivery and regulator equipment,XTR111 as U/I transition chip,currency as input control signal to control output pressure of electric proportional valve,the testing system will provide stable pressure for to-be detected MEMS capacitive pressure sensors within the range of allowable error.Meanwhile,based on the combined data processing technique by the ordinary least squares techniques and the principle of inverse function,the testing system will realize output signal collection,transformation and regulation of sensors by detecting the output signal of sensors with CDC technology and taking Laboratory Virtual Instrument Engineering Workbench?LabVIEW?as development platform.The author initially builds MEMS capacitive pressure sensors performance testing system,with which the author tests the output performance of samples to be tested in the laborotary and analyses the results.According to the data analysis,nonlineary error and repeatability error are separately 2.28%and 4.32%.Multiple experiments prove that when the pressure ranges from 10kPa to 120kPa,the relative error of the gas pressure regulating for the testing system is 0.48 percent,sensibility of MEMS capacitive pressure sensors is up to 7.364×10^-4pF/kPa.All the discovery in this thesis lays a foundation for the performance improvement of MEMS capacitive pressure sensors in the future.