Modelling and H∞ controller applied to a gyrometer

The aim of this paper is to design a sensor and improve its characteristics using control theory. The sensor studied is a gyrometer. The gyrometer is an angular velocity sensor used for the design of instruments of navigation for aeronautics. Its principle is based on the detection of Coriolis accelerations introduced by mechanical vibrations. This sensor considers mechanical phenomena (vibrations of a resonator) and electromagnetic phenomena (excitation and detection of these vibrations). The objective of the controller applied to this system is to guarantee linearity of the sensor. The output signal must be represented as follows: Ωˆ = K₁ (Ω + K₀) with constants K₀ and K₁. K₁ represents the scale factor, K₀ the bias and Ω the real rotate speed to measure. The difficulty lies in the fact that, on one hand, the various electric signals are oscillating and on the other, control signals and signals of measurements are multiplexed. They cannot coexist simultaneously.