Calibration of tri-axial MEMS accelerometers in the low-frequency range. Part I: comparison among methods

Two alternative experimental procedures for the calibration of tri-axial accelerometers have been compared with traditional method, performed according the procedures stated in Standard ISO 16063-21. Standard calibration is carried out by comparison with a Laser Doppler Vibrometer (LDV), used as primary reference transducer. The main sensitivities have been investigated and, where applicable, also transverse ones. Many aspects have been evaluated: the hypotheses about transverse sensitivities, the simplicity of the procedure, the number of measurements needed, the effect of typology of transducer, depending on electrical and geometrical contributions. Two different accelerometers have been tested, a piezoelectric accelerometer and a capacitive MEMS accelerometer. A low frequency range of vibration has been investigated, 3 Hz and 6 Hz, with amplitude of acceleration ranging from 2 ms-2 to 20 ms-2. A satisfactory reproducibility of methods has been verified, with percentage differences less than 2.5%. Anyway, pros and cons of each method are also discussed with reference to their possible use for easy and quick calibration of low-cost tri-axial accelerometers