Thermal Stabilization of Quality Factor for Dual-Axis MEMS Gyroscope Based on Joule Effect <i>In Situ</i> Dynamic Tuning
Jian Cui, Qiancheng Zhao
Abstract
Quality factor has played a crucial role in determining the temperature and antishock performance of a microelectromechanical system gyroscope. This article presents an innovative approach to enhance the thermal stability of quality factor for a micro resonant sensors based on Joule effect <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in situ</i> 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 ∼150 ppm from −40 °C to +60 °C, which achieves only ∼30 ppm 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 °C range. This technique is also promising for enhancing the antishock performance.