Design and Implementation of a Multiple-Beam Tuning-Fork Gyroscope

This paper presents the design, fabrication, and experimental results of a multiple-beam tuning-fork gyroscope (MB-TFG). Based on a numerical model of thermoelastic damping, a multiple-beam tuning-fork structure is designed with high Quality factors (Qs) in its two operation modes. A simple mask that defines the device through trenches is employed to implement this MB-TFG design on silicon-on-insulator wafers. The highest measured Qs of the fabricated MB-TFGs in vacuum are 255,000 in the drive-mode and 103,000 in the sense-mode, at a frequency of 15.7kHz. Under a frequency difference of 4Hz between the two modes (operation frequency is 16.8kHz) and a drive-mode vibration amplitude of 3.0μm, the measured rate sensitivity is 80μV_PP/°/s with an equivalent impedance of 2.5MΩ. The calculated overall rate resolution of this device is 0.377hr°/√Hz.