Cantilever Beam Microgyroscope Based on Frequency Modulation

This paper reports on-going research progress towards the development of an innovative frequency modulation MEMS gyroscope. The microgyroscope design includes a cantilever beam with a proof mass at its free end coupled electrostatically with two fixed electrodes. The beam is designed with silicon nitride and a layer of electrode material (Au). The microgyroscope undergoes coupled flexural vibrations in two orthogonal directions when subjected to base rotation around the beam's longitudinal axis. The rotation rate is measured by detecting the shift in the frequencies of the two closely spaced global vibration modes. A modeling framework is presented here for the development of the microgyroscope's frequency equation. The governing equations are derived using the Extended Hamilton's Principle and solved numerically to incorporate the nonlinear behavior. Currently, the device is in the process of fabrication using Silicon on Insulator (SOI) wafer using a micromachining process, including Deep Reactive Ion Etching.