A Novel Wide-Bandwidth In-Run Mode-Matching Technique for MEMS Vibratory Gyroscopes

Micro-electro mechanicalsystems (MEMS) gyroscope's performance is significantly constrained by mode frequency split. Therefore, a high-practicality mode-matching technique is crucial for advancing gyroscope technology. In this article, a novel wide-bandwidth in-run mode-matching technique based on the quadrature stiffness modulation is presented. Electrical feedthrough effect was considered for the first time in the previous sideband excitation tuning schemes that utilize feedback force electrodes for signal injection, and its impact is confirmed through experiments. Then the principle of the proposed method is introduced in detail, by modulating the quadrature stiffness modulation signal onto the drive displacement utilizing the quadrature electrodes. This method not only eliminates the impact of feedthrough effects but also greatly enhances the range of sideband frequencies. Moreover, the self-clocking scheme allows for the gain factor to remain consistent, thereby strengthening the method's adaptability and engineering practicality. Finally, the effectiveness of the proposed solution is experimentally verified and demonstrated in the dual-mass vibratory gyroscope. The results of experiments show that the frequency of the sideband can reach up to 900-Hz away from drive frequency, the bias instability and the angle random walk of MEMS gyroscope is 0.146<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula>/h and 0.015<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula>/√ h with 116-Hz bandwidth and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm 500^{\circ }$</tex-math></inline-formula>/s measuring range, respectively, when adopting the mode-matching method.