Vibrating structure gyrometer with at least one tuning fork

摘要

Vibrating structure gyrometer with at least one tuning fork, produced by micro-machining from a thin plate, the said tuning fork comprising a pair of mobile inertial assemblies (EIM1, EIM2) linked by a coupling assembly (1). A tuning fork comprises two controlled electrodes (9, 9′) for equilibration of the sense resonator and electrostatic adjustment of the frequency of the sense resonator along the sense axis y which are respectively associated with the two mobile inertial assemblies (EIM1, EIM2) of the said tuning fork, and control means (UCE) adapted for applying two respective continuous electrical voltages V1 and V2 to the said two electrodes (9, 9′) simultaneously satisfying the relations:;V12+V12=2⁢(fy⁢⁢_⁢⁢initial-fy⁢⁢_⁢⁢final)μfandV12-V22=cy⁢⁢_⁢⁢initiala⁢⁢λf.

主权项

1. Vibrating structure gyrometer with at least one tuning fork, produced by micro-machining from a thin plate, the said tuning fork comprising a pair of mobile inertial assemblies (EIM1, EIM2) linked by a coupling assembly (1), one mobile inertial assembly (EIM1, EIM2) being furnished with first stiffness elements (2, 2′) essentially deformable in the plane of the plate along a drive axis x and with second stiffness elements (3, 3′) essentially deformable in the plane of the plate along a sense axis y substantially perpendicular to the x axis, the gyrometer comprising, furthermore, for the tuning fork, two first controlled electrodes (4, 4′) for electrostatic excitation along the drive axis x which are respectively associated with the two mobile inertial assemblies (EIM1, EIM2), two second controlled electrodes (5, 5′) for capacitive detection of the drive resonator along the drive axis x which are respectively associated with the two mobile inertial assemblies (EIM1, EIM2), two third controlled electrodes (6, 6′) for capacitive detection of the drive motion along the sense axis y which are respectively associated with the two mobile inertial assemblies (EIM1, EIM2), and
two fourth controlled electrodes (9, 9′) for equilibration of the sense resonator and electrostatic adjustment of the frequency of the sense resonator along the sense axis y which are respectively associated with the two mobile inertial assemblies (EIM1, EIM2) of the said tuning fork, characterized in that it comprises: control means (UCE) adapted for applying two respective continuous electrical voltages V1 and V2 to the said two fourth electrodes (9, 9′) simultaneously satisfying the relations:V12+V12=2⁢(fy⁢⁢_⁢⁢initial-fy⁢⁢_⁢⁢final)μfandV12-V22=cy⁢⁢_⁢⁢initiala⁢⁢λf in which: fy—initial represents the initial resonant frequency, when the electrical voltages V1 and V2 are zero, of the sense mode along the sense axis y, in Hz, fy—final represents the final resonant frequency of the sense mode along the sense axis y to be adjusted, in Hz, and μf represents a coefficient of sensitivity of the frequency of the sense mode to the square of the electrical voltage applied to the said fourth electrodes (9, 9′), in Hz·V2, cy—initial represents the initial sensitivity of the gyrometer, when the two electrical voltages V1 and V2 are zero, to linear accelerations along the sense axis y in deg·h−1·G−1, a represents a coefficient characterizing the influence of a discrepancy in stiffness between the two branches of the tuning fork on the sensitivity of the gyrometer to linear accelerations along the y axis, in deg·h−1·G−1·N−1·m, possibly able to vary as a function of the frequency of the acceleration, λf represents an electrostatic stiffness coefficient dependent on the said fourth electrodes (9, 9′) in N·m−1·V−2, V1 and V2 are expressed in Volts, and G equals 9.81 m·s−2.