Resonance Interference Research of MEMS Inertial Sensors and Algorithm Elimination

The mechanical structure of MEMS inertial sensors is a spring-mass-damper system, which is susceptible to interference near the resonant frequency. This work compared the resonance interference effects of mechanical vibrations and high frequency sound waves on inertial sensors. Three MEMS gyroscopes ADXRS620 were interfered by vibrations and sound waves near the resonant frequency. The error outputs increased linearly with the increase of interference intensity. In amplitude sweep experiment, the max error could reach 126.00 °/s, which seriously affect the normal operation of the gyroscope. The waveforms of gyroscope outputs under acoustic and vibration interference were almost coincident, which showed the similarity of acoustic and vibration interference. However, the MEMS accelerometer ADXL103 has a very different performance under acoustic and vibration interference, not only the resonant frequency and max error change, but also the error output and interference intensity are nonlinearly related. In amplitude sweep experiment, the max error could reach 9.78 m/s2. In addition, to produce the same effect on MEMS inertial sensors, the power required of vibration interference was much less than that of acoustic interference. The effectiveness against vibration interference of the filtering algorithm based on orthogonal demodulation was verified by testing the self-developed gyroscope. To the best of our knowledge, it is the first time that use the IQ two-channel orthogonal demodulation filtering algorithm to eliminate vibration interference. The elimination effect was over 97%.