A Rapid Circuit Phase Error Identification and Compensation Method for MEMS QMG Achieving 99.7% Reduction in ZRO Drift

To solve the problem of circuit phase error induced quadrature error coupling into the rate output of the gyroscope operating in force-to-rebalance (FRB) mode, a rapid circuit phase error identification and compensation method is proposed in this paper. Firstly, the main sources of phase error in control circuit and the influence of phase error on drive mode and sense mode of micro-electro-mechanical system (MEMS) quad mass gyroscope (QMG) are theoretically analyzed. Then, a rapid circuit phase error identification and compensation method utilizing Recursive Least Squares (RLS) algorithm is proposed, achieving identification time under 1 s and 99.7% reduction in zero-rate output (ZRO) drift. This method leverages the disparity between the magnitudes of quadrature error and damping coupling error during the rapid temperature rise of the gyroscope after startup. The output of closed-loop quadrature suppression and FRB loop is used as the input of the RLS algorithm. The algorithm is carefully engineered to ascertain the phase error within 1s, thereby facilitating the expeditious rectification of the control circuit’s phase error. The effectiveness of the proposed method is verified through rotation experiments, with an identification error of less than 0.2%. The experimental results show that when using this method, the bias instability (BI) of the gyroscope is reduced from 2.218
$^{\circ}$
/h to 0.165
$^{\circ}$
/h, a total reduction of 13.4 times, while the ARW remains unchanged.