Online Identification and Compensation of Drive and Phase Errors for Whole-Angle Hemispherical Resonator Gyroscope Based on Sinusoidal Self-Excitation

Drive and phase errors of whole-angle (WA) hemispherical resonator gyroscope (HRG) in the control circuit cannot be neglected. These two errors represent the coupling and gain mismatch between control forces and the undesired phase delays accumulating in the control loops, respectively. The existing identification methods for these two errors are offline, and this nonreal-time compensation causes significant fluctuations in the performance of the gyroscope with changes in error parameters. This article proposes a novel sinusoidal self-excitation-based online error identification and compensation scheme. This scheme uses a sinusoidal self-excitation to modulate the angular incremental signal and quadrature control force carrying the drive and phase error information. Then, the real-time identification of the two errors is achieved through the modulated sinusoidal signal without affecting the angular rate detection in the low-frequency band. Experiments demonstrate that the drive and phase errors have been successfully identified and compensated for based on the proposed scheme. The peak-to-peak value of angle-dependent bias (ADBs) and bias instability (BI) decreased by 2.4 and 3.77 times, to 11.84^◦/h and 0.0061^◦/h. In addition, superior results are achieved after the anisodamping error compensation, with ADBs reaching 0.1802^◦/h and scale factor (SF) nonlinearity reaching 1.95 ppm. Compared to the 0.55^◦/h and 3.20 ppm obtained by compensating for only anisodamping error, it decreases by 3.06 and 1.66 times, respectively.