Study On Array-Type MEMS Piezoresistive Intelligent Pressure Sensor System

With the development of pressure sensor technology, the market puts forward higher requirements for MEMS (Micro-Electro-Mechanical System) piezoresistive pressure sensor. The traditional single range piezoresistive pressure sensors exist the shortcomings like low sensitivity, small range of poor linearity and obvious errors of hysteresis repeatability. The array multi-range pressure sensor measurement structure opens up a new way to solve the above problems. Therefore, an array of MEMS piezoresistive intelligent pressure sensor system is designed and implemented, in this paper.We propose an array MEMS pressure sensing structure which is made up of two groups of four pressure sensors with the pressures of 100kPa and 50kPa respectively.In further, the detailed theoretical calculation and finite element optimization simulation are done for the parameter of array sensor structure. Combined with the results of stress distribution based on finite element simulation, we confirm the size and material characteristics of the array MEMS pressure sensor according to the analysis about sensitivity and the ratio of signal to noise. And then, we complete the design of the sensor and test structure layout according to correct specific parameters.Besides, the array of pressure sensor chip processing and packaging are also completed based on the proposed production process. At the same time, the test structure of the basic parameter information is measured and analyzed. In further, an intelligent sensing and processing system for pressure sensing signals is designed based on completing the design and preparation of array MEMS piezoresistivepressure sensor. And, the s3c2440 microprocessor is deemed as the core part which can be used to collect signal and process data. Meanwhile, the temperature drift and hysteresis error compensation are realized by wavelet neural network based on genetic algorithm and least square method for measuring signal of array pressure sensor. In particular, the near and far fields' timing and precision acquisition on the temperature and pressure signals, digital signal processing, storage, display and transmission function is realized by the application of GUI Ethernet technology written in Qt/Embedded.The result of experimental calibration and test verification achieved with the temperature ranges from -20 ? to 20 ? shows that: 1) the non-linear range and the sensitivity of the designed array pressure sensor could reach to 2.18×10-4 and 0.082mV/V/kPa respectively in the pressure range of 0?50kPa; 2) when in the range of 50?100kPa, the non-linear range and the sensitivity of the designed array pressure sensor could reach to 7.02×10-3 and 0.032mV/V/kPa respectively; 3) when in the range of 0?100kPa, the overall error of our Intelligent pressure sensing system is maintained at ±0.849%FS. The involved results indicate that the developed array pressure sensor has good performance, which can provide a useful reference for the development of multi-range MEMS piezoresistive pressure sensor.