Development Of High Precision Wireless Strain Signal Acquisition

Wind tunnel tests play a very important role in aerodynamics research in aerospace engineering.Usually,in such mechanical tests,various physical quantities are tested by installing a test system composed of various sensor components and signal collectors.The physical quantity to be tested is converted into an electrical signal by the sensor,and then collected and processed.The air pressure on the surface of the aircraft is converted into a voltage signal by a bridge circuit through a strain pressure sensor attached to the surface of the aircraft.What this subject needs to collect is the voltage signal after the conversion.In this topic,compared with the existing various data acquisition systems,improvements have been made in volume and power consumption,and higher accuracy requirements have been proposed.Therefore,this subject has very important research significance and value in applied research and technological breakthroughs.According to the requirements of various technical indicators,this paper designs and manufactures a high-precision strain signal wireless data collector to collect the tiny voltage signal converted by the Wheatstone bridge circuit.Design a CC3220 SF microcontroller chip based on the ARM Cortex-M4 core.This chip integrates a network program processing module to achieve wireless data transmission.This chip is used as the main controller to control the collector for data collection and conversion.The ADC chip selects AD7124-8,converts the analog signal into a digital signal,communicates with the main control chip through the SPI bus,and finally uses the wireless network to transmit the data to the upper computer for analysis and processing.In terms of software,the host computer control interface is designed to complete the human-computer interaction and realize the convenience and operability of the data collector test.In order to realize the high-precision design of the data acquisition module,in the hardware design process,a differential lowpass filter is designed to filter out high-frequency interference.The analog-to-digital converter selects a 24-bit high-precision ADC chip,and uses the internal amplifier of the chip to replace the external signal amplifier circuit.In order to reduce the interference produced by the amplifying circuit.After the design of the data collector is completed,its technical indicators need to be tested and debugged,mainly to verify the functions of the data collector,and analyze the technical indicators such as system errors and precision.In the analysis of technical indicators,the least square method is used to analyze the regression equation of the collected data,and the collector is calibrated to improve its accuracy.The test results show that the maximum measurement error of the data collector does not exceed 0.02%,and its indicators meet various technical requirements.