Vibratory Gyroscopes

The paper presents an analytical review of vibratory gyroscopes manufactured using various technologies: silicon microelectromechanical systems (MEMS) technology, high-precision metal alloy machining, micro-glassblowing, and quartz glass technologies. A mathematical model of an ideal vibratory gyroscope, similar to a classical Foucault pendulum, is presented. It is shown that three methods of output signal generation can be used in MEMS vibratory gyroscopes: amplitude-modulated, frequency-modulated, and integrating methods. A description of the structure of a compensation type MEMS gyroscope is provided. The Bryan effect in the excitation of standing waves in cavity and ring resonators is described. It is shown that hemispherical resonator gyros (HRG) with high-Q quartz resonators can serve as integrating gyroscopes, while HRG with metal resonators can serve as angular rate sensors (rate gyros). The designs of direct-measuring and compensation type HRG are described.