Study On Pressure Measurement System Based On Static Pressure Head And Silicon-Aluminum Hybrid Structure Array

With the increasing market demand and the gradual improvement of industry standards,the performance requirements of MEMS piezoresistive pressure sensors have also increased.Traditional piezoresistive pressure sensors have the disadvantages of lower accuracy,higher temperature drift,lower sensitivity,and susceptibility to wind speed.A constant temperature pressure measurement system based on a highly sensitive hybrid structure array and a static pressure head device provides a solution to the above problems.For this purpose,a pressure sensor measurement system based on MEMS silicon-aluminum hybrid structure array with static pressure head and constant temperature control function is designed and researched in this paper.Firstly,a silicon-aluminum hybrid structure array pressure sensor with a temperature compensation structure is designed.The single silicon-aluminum hybrid structure is formed by the contact between the doped silicon and metal aluminum.The theoretical derivation illustrates that the silicon-aluminum hybrid structure array has an enhanced piezoresistive effect.Combining ANSYS finite element stress simulation and theoretical calculation,the sensitivity and signal-to-noise ratio of the hybrid structure array pressure sensor are investigated,and the structure and doping concentration of the array sensor are optimized.According to the optimization results,the layout of the array sensor and the corresponding manufacturing process are designed,and then the manufacture of the array sensor and the constant temperature control package of the chip are completed.Secondly,a static head device with a temperature control system is designed to reduce the interference of air pressure measurement caused by natural wind speed and direction.Based on Fluent software,CFD simulation was carried out to optimize the structural parameters of the static pressure head,and the influences of altitude,wind speed,and wind direction angle on the effects of static pressure were discussed.The static pressure head was manufactured by 3D printing.The static pressure and constant temperature anti-icing effects of the static pressure head device were verified by experiments.Then,the software and hardware design of the array pressure measurement system is completed.The system hardware uses STM32F407 microprocessor as the main control chip,which can collect and process the temperature and pressure signals,and control the heating circuit by PID algorithm to achieve the constant temperature effect of the system.The system software implements multi-threaded operations such as signal acquisition,constant temperature control,and transmission communication based on the RT-Thread operating system.The data transmission function of the measurement system is realized through the network communication and the Win Form host computer.Aiming at the near-ground sounding UAV application platform,supporting functions such as long-distance data transmission,satellite positioning,and posture acquisition have been expanded.Finally,systematic experimental tests and temperature compensation effects analysis of the silicon-aluminum hybrid structure array pressure sensor were performed.The experimental results show that:in the range of-20?to 50?,in the pressure range of 10k Pa?370k Pa,the constant temperature effect of the array sensor is obvious.The sensitivity of the sensor combined with hardware temperature compensation and constant temperature control is 0.251m V/V/k Pa,and the coefficient of thermal sensitivity drift is 1.52×10^-2%FS/?.The function correction method compensation can effectively reduce the non-linear error,hysteresis error and repeatability error of the sensor.After compensation,the comprehensive accuracy of the array sensor can reach 2.49%FS.In this paper,through software and hardware compensation and constant temperature design,the static pressure head is used to improve the measurement accuracy of the sensor and reduce the effect of temperature drift.It provides a useful reference for the research of high-performance pressure sensors based on silicon-aluminum heterostructure.