Fast Identification and Compensation for Actuation Electrode Errors of Rate Integrating Gyroscopes

Identification and compensation methods for different sources of errors have been reported in literature for hemispherical resonator gyroscopes (HRGs). HRGs working in the whole-angle (WA) mode, also known as rate-integrating gyroscopes (RIGs), require strict symmetry of the physical parameters of the mechanical resonator and the resonator-electrode assembly. The errors induced by actuation electrodes are precision-limiting factors that have not been as well discussed as errors like stiffness and damping anisotropy. In this article, a fast identification and compensation method for actuation electrode errors is proposed based on virtual rotation. The mechanism of the residual angle-dependent bias (ADB) induced by actuation electrode errors of RIGs is analyzed and explicit formulas are established for the first time. Based on the analysis, errors were identified by applying virtual rotation, and compensation was implemented by applying a decoupling matrix on the control forces of a RIG. After compensation, the residual ADB and the scale-factor nonlinearity of the RIG were decreased by 32 and 3 times, respectively and the results of 1 h test indicate that the bias instability (BI) and the angle random walk (ARW) decreased from 0.04°/h to 0.015°/h and from 0.09°/ $\surd $ h to 0.073°/ $\surd $ h, respectively.