Analysis and Compensation of Bias Drift of Force-to-Rebalanced Micro-Hemispherical Resonator Gyroscope Caused by Assembly Eccentricity Error

Aiming at the excitation coupling error caused by assembly eccentricity error in micro-hemispherical resonator gyroscope (
$\mu $
HRG), this paper proposes a method to identify excitation coupling coefficients by using the relationship between input angular velocity and excitation forces during mode reverses. Firstly, this paper studies the influence mechanism of eccentricity error on displacement detection and electrostatic excitation under force-to-rebalanced (FTR) mode. Furthermore, theoretical derivation and simulation results show that the coupling error of excitation force will lead to the mutual coupling between the driving and the sensing loops, which reduces the stability of the driving force and introduces additional zero-bias drift into the sensing mode. According to the proposed identification method of the coupling coefficient of excitation force, the coupling coefficients are calibrated, and the principle of direct compensation in the FPGA system is given. The experimental results show that in the FTR mode, the driving force amplitudes at different input angular rates and the zero-bias drift at room temperature before and after error compensation are compared, which verifies the effectiveness of the proposed error calibration and compensation method. At room temperature, under the FTR mode, compared with the uncompensated test results, the average value of the measured bias stability (
$1\sigma $
) of the three groups is reduced from 74.667 °/h to 9.670°/h, which is improved by nearly 7.72 times. When at 40°C, the
$\mu $
HRG’s bias stability (
$1\sigma $
) is reduced from uncompensated 177.151°/h to compensated 9.256°/h. [2022-0174]