Bandwidth analysis of a microgyroscope vibrating in two orthogonal axes on the substrate plane

Abstract

A microgyroscope, which vibrates in two orthogonal axes on the substrate plane, is designed and fabricated. The shuttle mass of the vibrating gyroscope consists of two parts. The one is outer shuttle mass which vibrates in driving mode guided by four folded springs attached to anchors. And the other is inner shuttle mass which vibrates in driving mode as the outer frame does and also can vibrate in sensing mode guided by four folded springs attached to the outer shuffle mass. Due to the directions of vibrating modes, it is possible to fabricate the gyroscope with simplified process by using polysilicon on insulator structure. Fabrication processes of the microgyroscope are composed of amsotropic silicon etching by PIE, gasphase etching (GPE) of the buried sacrificial oxide layer, metal electrode fonnation. An electromechanical model of the vibrating mierogyroscope was modeled and bandWidth characteristics of the gyroscope were analyzed firstly. The analyzed characteristics ofthe gyroscope were evaluated by experiment. The gyroscope operates at DC 4V and AC 0. 1V in a vacuum chamber of lOOmtorr. The detection circuit consists of a discrete sense amplifier and a noise canceling circuit. Using the evaluated electromechanical model, an operating condition for high performance ofthe gyroscope is obtained

A laterally driven symmetric micro-resonator for gyroscopic applications

“…The microgyroscope is attached to a rotating reference frame xyz, which rotates with respect to the fixed reference frame XY Z about axis Z, which is coaxial to axis z. There have been many studies on dynamic models of comb-drive type microgyroscopes [5][6][7], but to the authors' knowledge, microgyroscopes with parallel sidewall type driving have not been widely researched.…”

“…The equation of motion of the microgyroscope in the sensing mode vibration can be assumed to be linear. The amplitude of vibration in the y direction can be obtained from equations (2b) and (5). If the driving mode vibration is simply sinusoidal, the amplitude of the sensing mode vibration Y induced by the Coriolis force can be written as…”