A Novel Design of High Resolution MEMS Gyroscope Using Mode-Localization in Weakly Coupled Resonators

Abstract

This paper presents a novel design for a high resolution microelectromechanical systems (MEMS) technology based resonant gyroscope using the mode-localization effect in weekly coupled resonators (WCRs) as a mechanism for sensing the input angular rate. The design consists of a single proof mass with two three degree-of-freedom (3-DoF) WCRs systems attached on either side. The MEMS gyroscope is designed according to the microfabrication constraints of the foundry process, silicon-oninsulator multi-user MEMS process (SOIMUMPs). The shift in the resonance frequency values, amplitude ratios of the WCRs, and amplitude ratios difference of two sets due to electrostatic stiffness perturbation, corresponding to the input angular rotation, are discussed as an output metric for the measurement of angular rate. The results show that the amplitude ratio difference as an output metric allows to achieve a linear output response and large dynamic range in comparison to the shift in the amplitude ratio and resonance frequency in 3-DoF WCRs in a single set. The dynamic range and resolution of the MEMS gyroscope in terms of maximum allowed resonators amplitude and noise floor is discussed. The proposed MEMS gyroscope design has a sensitivity of 62830 ppm/°/s based on a difference in the amplitude ratios of resonators in two 3-DoF WCRs systems and a dynamic range of ±100 °/s. The resolution of the MEMS gyroscope is 31.09 × 10 -6 °/s which is significantly higher than existing MEMS gyroscopes and is comparable to traditional bulky ring laser gyroscopes. This high resolution makes the proposed MEMS gyroscope design suitable for use in applications such as earth rotation rate measurement for gyrocompassing and high precision robotics INDEX TERMS Amplitude ratio, Finite-Element-Method (FEM),

Nonlinear vibration and amplitude ratio output performance of a resonant micro-gyroscope based on bifurcation detection

“…In summary, we take the first-order mode of the resonant beam as the working mode. Substitute k = 1 into equation (26) and j 1 (L/2) = 1 into equation (24). After simplification, the following equation can be obtained as:…”

“…In terms of micro-mass sensors, in 2020, Lyu et al [23] proposed a mode-localization micro-mass sensor consisting of a pair of electrostatically coupled unequallength double-ended fixed resonant beams and found that the relative sensitivity based on the amplitude ratio variation was improved by three orders of magnitude over that based on the frequency variation in the linear case. In terms of micro-gyroscopes, in 2021, Bukhari et al [24] developed a multi-DOF weakly-coupled microgyroscope using the mode-localization principle. They found that the relative sensitivity based on the amplitude ratio variation is three orders of magnitude higher than that based on the frequency variation with an angular velocity range of ±100°/s.…”

Design and dynamic analysis of a highly sensitive MEMS gyroscope based on mode localization

“…Recently, to significantly improve the sensitivity of MEMS sensors, the mode localization effect of weakly coupled resonator systems (WCRS) has attracted a lot of attention [14][15][16]. Mode localization is a physical phenomenon that occurs in periodic structures [17].…”

“…Previous research showed that using an AR based on mode localization as an output metric could increase the sensitivity of MEMS sensors by more than two orders of magnitude. In 2021, Bukhari et al [16] first combined a WCRS and traditional MEMS gyroscopes to realize the application of mode localization effects on MEMS gyroscopes, achieving a significant enhancement in mechanical sensitivity. However, there are still certain limitations in terms of dynamic range and frequency bandwidth.…”

Lateral Extensional Mode Piezoelectric ZnO-on-Nickel RF MEMS Resonators for Back-End-of-Line Integration

“…Due to the low deposition rates, the thickness of RF magnetron-sputtered ZnO films is often limited to a couple of micrometers or less. Moreover, the fabrication tolerance and yield of thin-film ZnO lateral-extensional mode resonators are affected by the releasing step, as the residual stress causes suspended ZnO structural layers to buckle or even fracture [ 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. To circumvent these issues, this work investigates the employment of a nickel thin film, which is deposited by a low-temperature electroplating process, as the acoustic structural material for the vibrating micromechanical resonator body.…”