Precision mode matching of MEMS gyroscope by feedback control

This paper reports on mode matching of a MEMS gyroscope using simplified displacement feedback and reduces the frequency split between the two modes to less than 0.01 Hz. Mode matching is shown to improve the gyro performance significantly and reduce the bias stability from 3 degree/hour to 0.5degree/hour. The displacement feedback matching scheme provides an in situ matching control that may augment the generally coarser electrostatic tuning method. The control has been realized in a high performance DSP based rate gyroscope control system and experimental results show the effectiveness of the control algorithm.