A Quadruple Mass Vibrating MEMS Gyroscope With Symmetric Design

Abstract

This article presents a new microelectromechanical system (MEMS) quadruple mass gyroscope (QMG) with symmetric design. Similar to the wine-glass vibrating gyroscope, the reported QMG has a symmetric structure design both in the driving and sensing modes. The quadruple mass is coupled together using the central coupling springs and four tapered levers for the synchronization of the anti-phase driving motions. The reported QMG largely reduces the common mode signals due to accelerations and vibrations by the mechanical suppression. The momentum and torque balance in both driving and sensing directions contribute to ultra-low energy dissipation through the anchor, leading to a high quality factor ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$Q$</tex-math></inline-formula> ) and high resolution. The experimental measurement results show that the QMG demonstrates an Allan variance bias instability of 5.9 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ /$</tex-math></inline-formula> h and a white noise level about 0.28 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ /\sqrt{h}$</tex-math></inline-formula> , which are dominated by the flicker and thermal noise from the integrated circuit, respectively. The measured scale factor is 94.98 LSB/( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ /$</tex-math></inline-formula> s) with a nonlinearity of less than 600 ppm in the full-scale range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 300°/s. The reported QMG demonstrates a new way to reach potential high-performance gyroscope designs for achieving high precision inertial measurement units.