4. Vibrating gyro control electronics

Gyroscope mode

The stationary nature of the elliptical shape of the vibration trajectory is linked to the ideal gyroscope model: absence of damping, identity of the natural frequencies of the two modes, absence of external forces. In practice, this stationarity of the elliptical orbit is challenged by damping of the vibration amplitude (mechanical losses), Lissajoux curves (slightly different beats between the two eigenmodes), etc. Control electronics are therefore required, if only to keep the amplitude of vibration constant (as in spinning top gyroscopes, to maintain the speed of rotation). For this purpose, an electrically controlled reference oscillator is used, which, by demodulating the detector signals of the two vibration modes, provides the characteristics of the ellipse: four parameters a, b, θ and ζ. Three electronic loops control...