Dynamics of rotating and vibrating thin hemispherical shell with mass and damping imperfections and parametrically driven by discrete electrodes

A parametric electrode is normally used in hemispherical resonator gyroscopes, operating in the whole angle regime, for maintaining the amplitudes of vibratory patterns. It is well known that, due to variation of the gap between the resonator and parametric electrode, a drift of the vibrating pattern is obtained. This drift is similar to the gyro drift stipulated by the Q-factor imperfections and substantially deteriorates the quality of the hemispherical resonator gyroscope. In the present paper, we consider the methods of compensation of these drifts by means of special control of the vibrating pattern by a sectioned parametric electrode. Compensation of the drifts is achieved through amplitudes of voltage and phase manipulations at the sectioned parametric electrodes. The side effect of this control consisting of spurious splitting of frequencies of the vibrating pattern is discussed.