Active structural error suppression in MEMS vibratory rate integrating gyroscopes

Abstract

Due to restrictive tolerancing in microfabrication, structural imperfections that reduce performance of fabricated micro devices are typical. In microelectromechanical vibratory gyroscopes, feedback control is a common strategy in attempting to correct the imperfections. However, a purely feedback control can be insufficient for compensation of all the errors, requiring post processing in the form of laser trimming to achieve higher levels of performance. In this paper, we explore another alternative: the design and implementation of a dual stage control architecture with self-calibration and feedback capabilities. The self-calibrative portion of the control identifies and electronically "trims" large imperfections, while the feedback control compensates for remaining small nonidealities and in-operation perturbations. Presented here is an algorithm for in-situ imperfection identification based on the dynamic response of the device. A realization of the dual stage control architecture is proposed for a gyroscope using nonlinear electrostatic parallel plate actuators. Modeling and simulation results which demonstrate successful compensation of imperfections with the proposed architecture for a device with 10% fabrication error appearing in the form of stiffness nonidealities and subjected to further 1% in-run perturbations are presented.Index Terms-Error suppression, microelectromechanical systems (MEMS), rate integrating gyroscopes, smart MEMS.

Energy-efficient full-range oscillation analysis of parallel-plate electrostatically actuated MEMS resonators

“…β n e jnωt with β n = ∞ p=−∞V n−pVp (21) being β n the n-th order amplitude. Using these definitions on equation (13) and rearranging terms, the complete system dynamics can be represented as follows…”

“…For this reason, they are the basic building block for a wide variety of sensors. The list include accelerometers [31] and gyroscopes [21], temperature sensors [10], gas sensors [4] and mass sensors [28] among others. The main challenge is the nonlinearity of the parallel-plate electrostatic force that leads to the Pull-in phenomena [8].…”

A Survey of Modeling and Control Techniques for Micro- and Nanoelectromechanical Systems

“…This circuit featured attractive properties such as low power consumption as well as ease of sensor integration. A dual-stage control algorithm that provided on-site identification of imperfections based on the dynamic response of the device and compensated for it using nonlinear electrostatic parallel plate actuators was proposed in [130]. In this paper, the authors first showed that using feedback alone to compensate for large structural imperfections (to the tune of 10%) would seriously compromise the device performance.…”

MEMS Gyroscopes for Consumers and Industrial Applications

“…The quadrature error requires to be compensated, since it detrimentally affects the measurement. Usual compensation methods consists of either rebalancing the mechanical structure (with mechanical or electrostatic methods - (Painter & Shkel, 2003; Weinberg & Kourepenis, 2006)) or canceling the error from the measurement (using a feed-forward cancellation scheme - (Antonello et al, 2009;Saukoski et al, 2007)). …”