Trajectory-Switching Algorithm for a MEMS Gyroscope

The motion of a conventional force-balancing controlled gyroscope in a mode-matched operation does not have sufficient persistence of excitation, and as a result, all major fabrication imperfections cannot be identified and compensated for. This paper presents an adaptive force-balancing control for a microelectromechanical-system z-axis gyroscope using a trajectory-switching algorithm. The proposed adaptive force-balancing control supplies additional richness of excitation to the internal dynamics of the gyroscope by switching the trajectory of the proof mass of the gyroscope, and it provides quadrature compensation, drive- and sense-axis frequency tuning, and closed-loop identification of the angular rate without the measurement of input/output phase difference. This algorithm also identifies and compensates the cross-damping terms which cause zero-rate output.