Dynamic characteristics of vibratory gyroscopes

Although there have been test results on microgyroscope dynamic characteristics, quantitative results relating the dynamic properties to microgyro design and operating parameters are not yet available. In this paper, we study the dynamic characteristics of a vibrating wheel microgyroscope. In vibratory microgyroscopes, the mechanical structure is driven into oscillatory motion. Consequently, the angular velocity input to the sensor is multiplied by the periodic driven motion. In order to recover the angular velocity input from the sensor responses, a demodulation must by carried out. Therefore, the differential equation governing the gyro input and output is not time invariant. The frequency response for the time-variant linear system is obtained through the demodulated and low-pass filtered steady-state output to sinusoidal excitations. With further assumptions of large Q value and close frequency match between the driven mode and sense mode, we obtain a time invariant model for the microgyroscope which is much simpler to use in the design of the microgyroscopes.