Research Of Micromachined Capacitive Accelerometer Automatic Calibration And Performance Testing System

In recent years, with the rapid development of micro-mechanical systems technology,the miniaturization of sensor has been improved, represented by micro-mechanical inertialsensors of the micro accelerometer application more widely, how to calibrate themicro-mechanical accelerometer and the performance test is also one of the importantcontent of the research. This paper presents a set of micro-mechanical capacitiveacceleration sensor performance test system based on virtual instrumentation, dataacquisition module and a graphical programming language LabVIEW, and put forward therelevant algorithm of automatic calibration and parameter test. The system consists ofhardware such as computers, indexing table and oven, as well as data acquisition module,Micro-accelerometer data is transmitted to the computer through the output circuit and thedata acquisition module, finally using the LabVIEW toolkit, data processing module forthe analysis of the data processing, display, store, and report forms printing, so as toultimately achieve micro-mechanical accelerometer automatic calibration and performancetesting purposes.The main works of this paper are as follows:(1)Make the communication between data acquisition module and signalconditioning module. Through LabVIEW SDW function, make the digital I/O ports of thedata acquisition module, so as to simulate SPI protocol, to realize the communication withthe EEPROM of signal conditioning module. In order to achieve the programmable controlsignal conditioning modules and output signal acquisition.(2)For capacitive accelerometer bias voltage and scale factor calibration, introducesa kind of automatic calibration method: three-point static calibration method. After the userpreset bias voltage and scale factor, LabVIEW software applications written by three staticcalibration methods, realizes the automatic calibration of the bias voltage and scale factor.Experimental results show that: through the multiple automatic scaling, sensor scale factorrelative error is0.79%.(3)Reference accelerometer test standard, develop the capacitive accelerometer performance test method, test platform is established. According to the test plan, thecapacitive accelerometer performance was tested. The test results are as follows: the scalefactor of the accelerometer is-66.489mv/g, zero bias stability is1.536732mg, scale factorrepeatability is450PPM, zero bias instability is0.361mg，nonlinearity is0.2945%.