Adaptive oscillator control for a vibrational gyroscope

We present an adaptive controller for the drive axis of a vibrational gyroscope. A piezoelectrically driven gyroscope is operated as an oscillator circuit, by using a destabilizing positive feedback with automatic gain control. We adapt the feedback loop gain to obtain the desired amplitude for the oscillation and a parameter of the phase shift component in the feedback loop to yield a 90/spl deg/ phase shift. No sinusoidal driving input is required, and naturally occurring noise is the only input. The resulting oscillation is at the drive axis resonant frequency.