Identification and Compensation of Gain Mismatches for Whole-Angle Microhemispherical Resonator Gyroscope Based on Modal Reversal

This article investigates the influence of gain mismatches in whole-angle (WA) microhemispherical resonator gyroscope (
$\mu $
HRG) and proposes a gain mismatch identification method based on modal reversal. The gain mismatches considered here contain detection and actuation gain mismatches in x/y channels of the
$\mu $
HRG. The operational principle of WA mode is introduced in this artile, followed by an analysis of the factors contributing to the gain mismatches. A dynamical model of WA
$\mu $
HRG encompassing gain mismatches is established for the first time through theoretical derivation. The influence of the gain mismatches on angle bias error and closed-loop control of WA
$\mu $
HRG is investigated by theoretical analyses and numerical simulations. By using the proposed modal reversal method, the gain mismatches of the
$\mu $
HRG are identified, and the gain mismatch compensation experiments are conducted accordingly. The experimental results suggest that after compensation, the peak-to-peak value of the angular rate fluctuation error of the WA
$\mu $
HRG decreased from 39.072°/s to 4.22°/s, a reduction of 9.26 times, and the peak-to-peak value of the angle bias error decreased from 19.05° to 1.124°, a reduction of 16.95 times. The results demonstrate the effectiveness of the proposed gain mismatch identification method based on modal reversal and the correctness of the established gain mismatch theoretical model, providing practical, theoretical guidance for error analysis of the WA mode in subsequent studies.