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

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 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 3000x down to similar to 150 ppm from -40 degrees C to +60 degrees C, which achieves only similar to 30 ppm of driving voltage stability with similar to 3500x 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 degrees C range. This technique is also promising for enhancing the antishock performance.