Two-mass system with wide bandwidth for SiOG (silicon on glass) vibratory gyroscopes

The paper describes a two-mass system for SiOG (silicon on glass) vibratory gyroscope so as to increase the stability of the device with wide bandwidth. A two-mass mass system has more than two masses and separates the resonant peaks of each mass. The variation of bandwidth and driving displacement according to the mass ratio of the two-mass system was analyzed, using MATLAB. This result was compared with that of a conventional single mass system gyroscope. In the 7 kHz resonant frequency design, the two-mass system has 395.3 Hz bandwidth, which is six times larger than a single mass system bandwidth, 58.5 Hz. The fabricated spring width is 3.4-3.6 μm, which is 4 μm in the design. Since the resonant frequency is influenced by the spring width, the measured frequency is 5.2 kHz, which is 7 kHz in the design. But, the measured bandwidth is 450 Hz, similar to the designed bandwidth (500 Hz). Also, the frequency difference between the driving and sensing part (210 Hz) is smaller than the wide bandwidth.