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

Abstract

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.

Effects of both the drive- and sense-mode circuit phase delay on MEMS gyroscope performance and real-time suppression of the residual fluctuation phase error

“…And the closed loop QN voltage using drive-mode SSB changes up to 4.5 mV. Note that the closed loop QN voltage using drive-mode DSB keeps unchanged, as expressed by equation (15). Likewise, when using MDSB in the drive mode, experiments show that effects of residual fluctuation error of the drive-mode circuit phase delay on the ZRO and QN voltage are the slightest compared to the other two cases.…”

“…Thus, for the gyroscope sense mode, typical strategies include the open loop [10], forcerebalance closed loop with quadrature stiffness nulling [11] and force-rebalance closed loop with quadrature force correction [12]. Considering the complex and mutually coupling control loops in the gyroscope system, several advanced control theories including the periodic averaging method [13,14], zero-pole cancellation method [15] and order-reduction linearization method [16] can be adopted to simplify the system design and optimization.…”

Analysis of Frequency Response and Scale-Factor of Tuning Fork Micro-Gyroscope Operating at Atmospheric Pressure

“…The frequency response and the scale-factor of the gyroscopes have not been paid close attention in the literatures mentioned above. The frequency responses of gyroscopes with high Q -factor have been well studied [ 17 , 18 ]. However, as for gyroscopes operating at atmospheric pressure, the low Q -factor has a great impact on the characteristics of the frequency response and scale-factor.…”

“…However, as for gyroscopes operating at atmospheric pressure, the low Q -factor has a great impact on the characteristics of the frequency response and scale-factor. In [ 17 ], the demodulation phase, which is negligible for high Q cases but significant for low Q cases, is not included in the theoretical analysis. In [ 19 ], collateral modes of micro-gyroscopes, which provide mechanisms for the transfers of energy that are independent of angular rate, were analyzed through a three DOF model.…”

Construction and experiment on micro-gyroscope detection balance loop

“…S. Sung [4] investigates a new loop design approach of force balance control for the vibratory rate sensor, which takes advantages of the modified automatic gain control configuration in controlling the system's oscillating dynamics. B. Eminoglu [5] introduced a new baseband equivalent model for sense mode dynamics of a MEMS gyroscope providing a more accurate force-feedback controller design. J. Cui [6] presents a design method of force rebalance control for the sense mode of a micro-machined vibratory gyroscope, which is based on constraining sensitivity margin specifications via numerical optimization approach.…”