Thermal Stabilization of Quality Factor for Dual-Axis MEMS Gyroscope Based on Joule Effect In Situ Dynamic Tuning

Abstract

Quality factor has played a crucial role in determining the temperature and anti-shock performance of a microelectromechanical system (MEMS) gyroscope. This paper presents an innovative approach to enhance the thermal stability of quality factor for a micro resonant sensors based on Joule effect in-situ dynamic tuning for the first time. By unitizing an active control loop that adjusts the dissipation energy of a resistive element connected to the mechanical structure via monitoring the driving voltage, the device damping can be effectively tuned in real-time, thus stabilizing the quality factor. The proposed method is demonstrated on a vacuumed sealed monolithic dual-axis gyroscope. The results show that the relative variation of the Q-factor significantly reduced by more than 3000× down to ∼150ppm from -40℃ to +60℃, which achieves only ∼30ppm of driving voltage stability with ∼3500× reduction. Benefiting from the quality factor precise control capability, the electrical coupling from the drive mode to the sense mode is therefore suppressed, exhibiting more than three-fold times improvement of the zero bias thermal drift over 100℃ range. This technique is also promising for enhancing the anti-shock performance.