Design Of Micro-Pressure Sensor Based On Michelson Interference Principle

Extreme micro-pressure detection is a difficulty in the field of pressure detection.At present,the range of most micro-pressure sensors can be as low as about 0.1k Pa,and it is difficult to have the measuring range of micro-pressure sensor as low as 0.03 k Pa.Nowadays,many fields require extremely micro-pressure measurements such as Instrumentation,Industral Control and Aerospace.To achieve extreme micropressure measurement,one way is to use pressure-sensitive materials with higher strain coefficients than existing materials as pressure sensors,and the other is to use a suitably measurement method.In this paper,based on Michelson's interference fringes will change with tiny displacement of the object,designed a kind of micro-pressure sensor based on Michelson's interference principle,could effectively measure the interference fringe displacement,and the micro displacement of the diaphragm was calculated,and then according to the principle of Elastic mechanics to calculate the size of the diaphragm pressure.In this paper,an embedded system was used to collect the fringe image generated by Michelson's interference device,analyzed and processed the fringe image when the diaphragm was under pressure,and calculated the accurate displacement of the fringe.By establishing the mathematical model of pressure and displacement,the micropressure was calculated.The sensor adopts intelligent structure,The system hardware circuit was divided into five parts: image acquisition module,temperature measurement module,LCD display module,SD card storage module and external SRAM module.This paper designed each module circuit,and wrote the corresponding driver program.Image processing algorithms included image graying,background removal,filtering,binarization,fringe thinning and so on.Finally,the circuit welding,software debugging,system testing and other work were carried out for the micro-pressure sensor,and experimental data were obtained to verify the feasibility of the hardware circuit,software system and interference fringe processing algorithm.