Stability Boundary and Enhanced Solution of Dual-Mode Based Micro Gyroscope Mode Matching Technology.

During in-run mode matching under a dual-mode gyro scheme, the stability of the closed-loop control system has a boundary. This phenomenon will lead to the failure of the in-run frequency split calibration scheme when the initial mode mismatch is too severe to exceed the stability boundary. This paper gives a detailed analysis of this stability boundary through simulations and experiments. Results show that the length of the stable region will be affected by the resonant frequency and the value. High resonant frequency and low value will widen the stable region, but also reduce the sensitivity and rapidity of the calibration. In order to remove the limitation of the stability boundary while applying the in-run frequency split calibration under dual-mode architecture, this paper proposes an enhanced solution that combines both the dual-mode scheme and technology of mode switching. The application of mode switching achieves a pre-calibration of frequency split before the normal gyro operation. This solution is implemented in engineering on a hybrid gyro interface circuit prototype with single-mode and dual-mode. Validation experiments confirmed the effectiveness of this solution.