Open loop compensation of the quadrature error in MEMS vibrating gyroscopes

This paper presents a simple, yet effective approach for rejecting the quadrature error in MEMS vibratory gyroscopes. The proposed solution consists of an open loop compensation that is performed on the proof-mass displacement readout signal provided by a standard capacitive sensing interface based on parallel-plate capacitors. The compensating signal is generated and calibrated according to the nominal quadrature error to reject, and is injected into the system by means of a compensation circuit based on a dynamically reconfigurable capacitor bank. The compensation scheme described in the paper has been implemented on ASIC and experimentally tested on a real MEMS vibratory gyroscope. Experimental results show that the proposed solution assures good rejection capabilities, even for very large quadrature errors that unavoidably saturates the sensor readout interface.