A quadrature compensation method to improve the performance of the butterfly vibratory gyroscope

A simple and effective method for realizing the quadrature compensation of the butterfly vibratory gyroscope by electrostatic tuning is presented. The unique symmetrical structure of the butterfly vibratory gyroscope makes it a highly sensitive micro-electromechanical systems gyroscope. However, in the actual fabrication processes, due to the limited precision of the fabrication, the fabrication imperfections result in non-ideal geometries in the butterfly gyroscope structure, which leads to the quadrature error. The quadrature error has great influence on the performance of the butterfly vibratory gyroscope, such as the zero rate output, the detection resolution and the dynamic range. The quadrature error of the butterfly vibratory gyroscope is calculated theoretically, the influence of quadrature error on the performance of the gyroscope is analyzed, and the mathematical model of quadrature compensation is established. Therefore, the electrode structure of the butterfly vibratory gyroscope is optimized, and the design of the electrode areas of the adjusting axis is determined. Then, the experiment of quadrature compensation is carried out on the butterfly vibratory gyroscope. The experimental results show that the quadrature error can be controlled to the minimum. The feasibility of quadrature compensation in butterfly vibratory gyroscope is illustrated. According to the comparative experimental tested, the performance of the butterfly vibratory gyroscope is improved. The bias instability is reduced from 1.05°/h to 0.53°/h after suppresing the quadrature error. [Display omitted] •This paper systematically researched the origin and the influence of the quadrature error in the gyroscope.•The novel vibratory beam was designed and fabricated by wet etching combined with DRIE, which can improve robustness of fabrication imperfections so as to reduce the quadrature error in the structure.•The fabrication errors of the oblique beam were simulated and analyzed.•The experiment of quadrature compensation was carried out on the butterfly vibratory gyroscope. The experimental results showed that the quadrature error can be controlled to the minimum.•It was reported the detailed method for suppressing the quadrature error and demonstrated the improvement of the ZRO and BI of the gyroscope in this paper by experimental testing. A simple and effective method for realizing the quadrature compensation of the butterfly vibratory gyroscope by electrostatic tuning is presen