Effect of polarization voltage on the measured quality factor of a multiple-beam tuning-fork gyroscope

This paper presents a comprehensive study of the effect of polarization voltage on the measured mechanical Quality (Q) factor of a multiple-beam tuning-fork gyroscope. An experimental study is conducted to examine the effect of different variables in the experiment on the measured Q of the gyroscope. The experimental data show that the Q drops significantly with polarization voltage, while independent of ac drive voltage and feedback resistance. To identify the reason behind the Q drop with polarization voltage, the two loss mechanisms, thermoelastic damping and anchor loss, in the device are analyzed. Using a numerical model of thermoelastic damping capable of taking prestress into account, polarization voltage is found to have a negligible effect on the Q of the gyroscope. Due to the asymmetry of the fabricated devices resulting from fabrication variations, anchor loss is identified as the cause of the Q drop with polarization voltage. Based on the experimental data and related elastic wave theories, an analytical model of anchor loss is proposed to take polarization voltage into account.