Resonator configured to be integrated into an inertial angular sensor

Patent metadata

Field	Value
Publication number	US-11215456-B2
Application number	US-201816609054-A
Country	US
Kind code	B2
Filing date	Apr 13, 2018
Priority date	Apr 27, 2017
Publication date	Jan 4, 2022
Grant date	Jan 4, 2022

Abstract

The invention concerns a resonator 1 configured to be integrated into an inertial angular sensor, said resonator 1 comprising at least one mass suspended by mechanical springs 5 , a number N of pairs P i (2≤i≤N) of electrostatic springs 50 , said resonator 1 defining at least four axes of symmetry S 1 , S 2 , S 3 and S 4 , characterized in that: each pair P i consists of two electrostatic springs 50 each having a privileged axis of action, these electrostatic springs 50 being positioned so that their respective axes form a right angle; for at least one spring of one of the pairs and one spring of another pair, the angle formed by these two springs is equal to a predefined angle.

First claim

The invention claimed is:

1. An inertial angular sensor comprising a support, characterized in that it comprises a resonator, said resonator comprising at least two masses suspended by mechanical springs, a number N of pairs P i (2≤i≤N) of electrostatic springs, said resonator defining at least four axes of symmetry S 1 , S 2 , S 3 and S 4 , characterized in that:
each pair P i consists of two electrostatic springs each having a preferred axis D of action, these electrostatic springs being positioned such that the respective axes D thereof form a right angle,
for at least one spring of any of the pairs and at least one spring of any other pair, the angle formed by these two springs is equal to a predefined angle,
said at least two masses being connected to the support by the at least some of the N pairs of electrostatic springs and by at least some of the mechanical springs, said at least two masses of the resonator comprising an internal mass and an external mass coupled together by coupling springs, each mass being connected to the support by mechanical springs, and each mass being connected to the support by a number N of electrostatic springs.

2. The inertial angular sensor according to claim 1 , characterized in that the predefined angle is 45 degrees.

3. The inertial angular sensor according to claim 2 , characterized in that each pair P i is symmetrical to at least one other pair P j (with j≠i) with respect to at least one of the axes of symmetry S 1 , S 2 , S 3 and S 4 of the resonator.

4. The inertial angular sensor according to claim 1 , characterized in that each pair P i is symmetrical to at least one other pair P j (with j≠i) with respect to at least one of the axes of symmetry S 1 , S 2 , S 3 and S 4 of the resonator.

5. The inertial angular sensor according to claim 4 , characterized in that each spring of each pair P i forms an alpha=90/N degree angle with at least two of the four axes of symmetry S 1 , S 2 , S 3 and S 4 of the resonator.

6. The inertial angular sensor according to claim 1 , characterized in that each spring of each pair P i forms an alpha=90/N degree angle with at least two of the four axes of symmetry S 1 , S 2 , S 3 and S 4 of the resonator.

7. The inertial angular sensor according to claim 6 , characterized in that the external mass has a substantially square annular shape.

8. The inertial angular sensor according to claim 4 , characterized in that the external mass has a substantially square annular shape.

9. The inertial angular sensor according to claim 2 , characterized in that the external mass has a substantially square annular shape.

10. The inertial angular sensor according to claim 1 , characterized in that the external mass has a substantially square annular shape.

11. The inertial angular sensor according to claim 10 , characterized in that the masses have the same axes of symmetry.

12. The inertial angular sensor according to claim 6 , characterized in that the masses have the same axes of symmetry.

13. The inertial angular sensor according to claim 4 , characterized in that the masses have the same axes of symmetry.

14. The inertial angular sensor according to claim 2 , characterized in that the masses have the same axes of symmetry.

15. The inertial angular sensor according to claim 1 , characterized in that the masses have the same axes of symmetry.

16. A method for correcting the stiffness of a resonator integrated in an inertial angular sensor according to claim 1 , comprising the steps of:
measurement of the vibration frequencies of the resonator for different vibration orientations, using deformation sensors,
determination, on the basis of these measurements, of the failing stiffness K U of the resonator wherein K U is a function of stiffness at an angular vibration orientation around an axis perpendicular to a plane of movement,
calculation, from the failing stiffness K U , of the tensions to be applied to a selection of electrostatic springs,
application of the calculated tensions on the selection of springs,
repetition of the previous steps if the vibration frequency anisotropy of the resonator is greater than a threshold frequency anisotropy value.

17. The method according to claim 16 , characterized in that the threshold frequency anisotropy value is 1 Hz.

18. A method for correcting the stiffness of a resonator integrated in an inertial angular sensor according to claim 4 , comprising the steps of:
measurement of the vibration frequencies of the resonator for different vibration orientations, using deformation sensors,
determination, on the basis of these measurements, of the failing stiffness K U of the resonator wherein K U is a function of stiffness at an angular vibration orientation around an axis perpendicular to a plane of movement,
calculation, from the failing stiffness K U , of the tensions to be applied to a selection of electrostatic springs,
application of the calculated tensions on the selection of springs,
repetition of the previous steps if the vibration frequency anisotropy of the resonator is greater than a threshold frequency anisotropy value.

19. A method for correcting the stiffness of a resonator integrated in an inertial angular sensor according to claim 6 , comprising the steps of:
measurement of the vibration frequencies of the resonator for different vibration orientations, using deformation sensors,
determination, on the basis of these measurements, of the failing stiffness K U of the resonator wherein K U is a function of stiffness at an angular vibration orientation around an axis perpendicular to a plane of movement,
calculation, from the failing stiffness K U , of the tensions to be applied to a selection of electrostatic springs,
application of the calculated tensions on the selection of springs,
repetition of the previous steps if the vibration frequency anisotropy of the resonator is greater than a threshold frequency anisotropy value.

20. A method for correcting the stiffness of a resonator integrated in an inertial angular sensor according to claim 10 , comprising the steps of:
measurement of the vibration frequencies of the resonator for different vibration orientations, using deformation sensors,
determination, on the basis of these measurements, of the failing stiffness K U of the resonator wherein K U is a function of stiffness at an angular vibration orientation around an axis perpendicular to a plane of movement,
calculation, from the failing stiffness K U , of the tensions to be applied to a selection of electrostatic springs,
application of the calculated tensions on the selection of springs,
repetition of the previous steps if the vibration frequency anisotropy of the resonator is greater than a threshold frequency anisotropy value.

Assignees

• Safran
• Commissariat Energie Atomique

Inventors

• Onfroy Philippe
• Ragot Vincent

Classifications

• G01C19/5719 Primary

  using planar vibrating masses driven in a translation vibration along an axis · CPC title

• G01C19/5712

  the devices involving a micromechanical structure · CPC title