Adaptive Control for Conventional Modes of Operation of MEMS Gyroscopes
This report presents adaptive control algorithms for conventional modes of operation of MEMS z-axis gyroscopes. In an open-loop mode, an off-line self-calibration scheme is proposed for estimating fabrication imperfections and enhancing the performance of a gyroscope operating in open-loop mode. This scheme can be implemented during the initial calibration stage when the gyroscope is turned on, or at regular calibration sessions, which may be performed periodically. An adaptive add-on control scheme is also proposed for a closed-loop mode of operation. This scheme is realized by adding an outer loop to a conventional force-balancing scheme that includes a parameter estimation algorithm. This parameter adaptation algorithm estimates the angular rate, identifies and compensates the quadrature error, and may permit on-line automatic mode tuning. The convergence and resolution analysis show that the proposed adaptive add-on control scheme prevents the angular rate estimate from being contaminated by the quadrature error, while keeping ideal resolution performance of a conventional force-balancing scheme.