A new baseband equivalent model for sense mode dynamics and its effects on force-feedback controller design for MEMS gyroscopes

This paper introduces a new baseband equivalent model for the sense mode dynamics of a MEMS gyroscope providing a more accurate force-feedback controller design applicable to high-performance sensors with a small frequency separation between drive and sense modes. This new baseband equivalent model for sense dynamics correctly models the step response of the system allowing both “true prediction of the system bandwidth”, with an error less than 1%, and “proper control of the transient behavior” such as ringing, settling time, etc. It has also been demonstrated that the designed force-feedback controller based on the new model improves the angle random walk and bias stability performance of a MEMS gyroscope by a factor of 9 and 3, respectively, compared to the same controller architecture design based on the conventional over-simplified sense dynamic model.