Suppression and Compensation of Damping Asymmetry Errors in Whole-Angle Hemispherical Resonator Gyroscope

This article studied the primary sources, evolution rules, and influence mechanisms of the damping anisotropy of the whole-angle hemispherical resonator gyroscope from the perspective of the fabrication process and analyzed the influence of temperature change on the damping anisotropy. An error identification and compensation method is proposed to suppress the effect of the damping anisotropy error on the gyroscope’s bias error. According to the energy controller’s output, this method involves applying the recursive least squares method to identify the damping anisotropy error and the damping axis angle in real-time. Subsequently, a compensation signal is synthesized based on the identification results and applied to the angular rate control loop to compensate for the damping asymmetry error online. The experimental results show that the peak-to-peak value of the angular rate output harmonic error of the gyroscope is reduced from 0.023°/s to 0.005°/s after the error compensation, which is an improvement of about five times. In addition, the peak-to-peak value of the gyroscope angular dependent bias error decreases from 0.7072° to 0.08268°, which improves by $8.55\times $ , and the linearity of the angular measurements is also significantly improved. This methodology can be widely applied to gyroscopes operating in whole-angle mode, which is essential for fundamentally reducing the bias errors of the gyroscope induced by damping asymmetry.