Compensation of Assembly Eccentricity Error of Micro Hemispherical Resonator Gyroscope

A calibration and compensation method of eccentricity error caused by assembly error of micro-hemispherical resonator gyroscope (µLHRG) is reported. The influence mechanism of the eccentricity error on the excitation and detection of the gyroscope is analyzed. On this basis, the influence of the eccentricity error on the zero-bias drift and the scale factor in the force-to-rebalance (FTR) mode is analyzed. Using the eccentricity error parameters calibrated by the modal reversal method, the eccentricity error compensation experiment was carried out. The experimental results show that after the eccentricity error compensation, the driving loop basically does not change synchronously with the input angular velocity, which verifies the effectiveness of the proposed error calibration and compensation method. After the eccentricity error is compensated in FTR mode, the drive control loop will not be disturbed by the force balance excitation force coupling. At the same time, under the FTR mode, compared with the uncompensated test results, the bias stability
$(l_{\sigma})$
is reduced from 56.752° /h to 5.753° /h, which is improved by nearly 9.9 times. After the eccentricity error is compensated, the bias instability (Allan Variance) is reduced from 1.895° /h to 0.685° /h, which is improved by nearly 2.8 times. After the eccentricity error is compensated, the ARW is reduced from
$0.285^{\circ} /\sqrt{\mathrm{h}}$
to
$0.243^{\circ} /\sqrt{\mathrm{h}}$
, which is improved by nearly 1.2 times.