A novel method for finding the best excitation frequency of MEMS vibratory gyroscope

摘要

In this paper, a novel method is proposed for finding the best excitation signal frequency of the MEMS vibratory gyroscope sensors. In the proposed method, the amplitude of the drive mode displacement is the criterion to choose the proper excitation signal frequency. To assess the performance of the proposed method in comparison with other common ones, a PLL-based control loop is designed and simulated. According to the nonlinear behavior of the gyroscope, the excitation signal frequency would not converge and will oscillate within a 15 Hz range using the PLL-based control loop. To resolve the disturbing oscillations, an effective approach is proposed in which the frequency excitation signal will be constant and the drive mode amplitude will stop oscillating. The proposed method finds the best excitation frequency accurately. To this aim, a 2-degrees-of-freedom MEMS vibratory gyroscope is designed and simulated by CoventorWare software. To reflect the nonlinear behavior of the sensor, all the elements are considered nonlinear. The simulation results show the superb advantages of our proposed method in comparison to the classic state-of-the-art solutions.