Mode-matching in vibrating microgyros using an extremum seeking controller with switching logic

In order to improve the sensitivity and to reduce the readout circuit complexity of any angular velocity microsensor (vibrating gyroscope), it is crucial to reduce the frequency mismatch of its resonant modes of vibrations. In this paper, we consider the problem of designing an adaptive controller capable of automatically matching the resonant frequencies of the two main modes of vibration of a single axis vibrating microgyroscope, under the provision that there is an underlying mechanism that allows to control the frequency-mismatch by adjusting a suitable parameter. Similarly to what we have done in a previous work, the proposed control scheme is based on an extremum seeking procedure: however, differently from what done before, we avoid the use of a perturbation signal in the seeking process, thus conceveing a mode-matching controller that theoretically guarantees an improved frequency-matching accuracy.