ANGULAR RATE SENSOR

• US 20070272015A1
• Filed: 05/23/2007
• Published: 11/29/2007
• Est. Priority Date: 05/24/2006
• Status: Abandoned Application

• Current Assignee: Hitachi Metals (Thailand) Ltd.
• Original Assignee: Hitachi Metals (Thailand) Ltd.
• Inventors: Kazama, Atsushi, Nakamura, Shigeo
• Application Number:
  US11/752,335
• Publication Number:
  US 20070272015A1
• Time in Patent Office: Days
• US Class Current: 73/504.80
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type

Abstract

An angular rate sensor formed into a planar shape, which detects an angular rate around a first axis in the plane, includes a rotating oscillator rotatably supported in the plane and around the rotational axis in a direction of a second axis perpendicular to the first axis; vibration generating means which rotationally vibrates the rotating oscillator; and a first detecting oscillator and a second detecting oscillator which are disposed inside the rotating oscillator and separately on the right side and the left side of the rotational axis, and which are supported as being displaceable in a direction of the second axis. A first detecting unit and a second detecting unit, which detect vibrations of the respective first and second detecting oscillators in the direction of the second axis due to the Coriolis force, are respectively provided closer to the rotational axis than the first and second detecting oscillators are.

Claims

1. An angular rate sensor formed into a planar shape and configured to detect an angular rate around a first axis in the plane, the angular rate sensor comprising:

a rotating oscillator rotatably supported in the plane and around the rotational axis in a direction of a second axis perpendicular to the first axis;

vibration generating means which rotationally vibrates the rotating oscillator; and

a first detecting oscillator and a second detecting oscillator which are disposed inside the rotating oscillator and separately on the right side and the left side of the rotational axis, and which are supported as being displaceable in a direction of the second axis,

wherein a first detecting unit and a second detecting unit, which detect vibrations of the respective first and second detecting oscillators in the direction of the second axis due to the Coriolis force, are respectively provided closer to the rotational axis than the first and second detecting oscillators are.

2. The angular rate sensor according to claim 1, wherein the angular rate around the first axis is detected by finding the difference between detection signals detected in mutually reversed phases respectively by the first detecting unit and the second detecting unit.

3. The angular rate sensor according to claim 1, wherein acceleration in the direction of the second axis is detected by calculating the sum of detection signals detected in the same phase respectively by the first detecting unit and the second detecting unit.

4. The angular rate sensor according to claims 1, wherein

the first and second detecting units comprise:

a plurality of movable-side detecting comb-shaped electrodes bonded to the first and the second detecting oscillators; and

a plurality of fixed-side detecting comb-shaped electrodes each of which is a counterpart of the corresponding movable-side detecting comb-shaped electrode, and which are fixed in a way that part of side faces thereof face the movable-side detecting comb-shaped electrodes, and

a change in electrostatic capacitance due to a change in a gap between each movable-side detecting comb-shaped electrode and the corresponding fixed-side detecting comb-shaped electrode is used as detecting means.

5. The angular rate sensor according to claims 2, wherein

the first and second detecting units comprise:

a plurality of movable-side detecting comb-shaped electrodes bonded to the first and the second detecting oscillators; and

a plurality of fixed-side detecting comb-shaped electrodes each of which is a counterpart of the corresponding movable-side detecting comb-shaped electrode, and which are fixed in a way that part of side faces thereof face the movable-side detecting comb-shaped electrodes, and

a change in electrostatic capacitance due to a change in a gap between each movable-side detecting comb-shaped electrode and the corresponding fixed-side detecting comb-shaped electrode is used as detecting means.

6. The angular rate sensor according to claims 3, wherein

the first and second detecting units comprise:

a plurality of movable-side detecting comb-shaped electrodes bonded to the first and the second detecting oscillators; and

a plurality of fixed-side detecting comb-shaped electrodes each of which is a counterpart of the corresponding movable-side detecting comb-shaped electrode, and which are fixed in a way that part of side faces thereof face the movable-side detecting comb-shaped electrodes, and

a change in electrostatic capacitance due to a change in a gap between each movable-side detecting comb-shaped electrode and the corresponding fixed-side detecting comb-shaped electrode is used as detecting means.

7. The angular rate sensor according to claim 4, wherein one of surfaces where the movable-side detecting comb-shaped electrodes and the fixed-side detecting comb-shaped electrodes face each other includes a portion partially protruding toward the other surface.

8. The angular rate sensor according to claim 5, wherein one of surfaces where the movable-side detecting comb-shaped electrodes and the fixed-side detecting comb-shaped electrodes face each other includes a portion partially protruding toward the other surface.

9. The angular rate sensor according to claim 6, wherein one of surfaces where the movable-side detecting comb-shaped electrodes and the fixed-side detecting comb-shaped electrodes face each other includes a portion partially protruding toward the other surface.

10. The angular rate sensor according to claims 1, wherein the vibration generating means comprises first driving means which applies a force to the rotating oscillator in the perpendicular direction to the plane, the first driving means being disposed at an opposite side of the rotational axis as viewed from the first detecting oscillator;

and second driving means which applies a force to the rotating oscillator in the perpendicular direction to the plane, the second driving means being disposed at an opposite side of the rotational axis as viewed from the second detecting oscillator.

11. The angular rate sensor according to claims 2, wherein the vibration generating means comprises first driving means which applies a force to the rotating oscillator in the perpendicular direction to the plane, the first driving means being disposed at an opposite side of the rotational axis as viewed from the first detecting oscillator;

and second driving means which applies a force to the rotating oscillator in the perpendicular direction to the plane, the second driving means being disposed at an opposite side of the rotational axis as viewed from the second detecting oscillator.

12. The angular rate sensor according to claims 3, wherein the vibration generating means comprises first driving means which applies a force to the rotating oscillator in the perpendicular direction to the plane, the first driving means being disposed at an opposite side of the rotational axis as viewed from the first detecting oscillator;

and second driving means which applies a force to the rotating oscillator in the perpendicular direction to the plane, the second driving means being disposed at an opposite side of the rotational axis as viewed from the second detecting oscillator.

13. The angular rate sensor according to claim 10, wherein the vibration generating means comprises third driving means which applies a force to the rotating oscillator in the perpendicular direction to the plane, the third driving means being disposed in any one of one side and two sides of a surface of the first detecting oscillator parallel to the plane;

and fourth driving means which applies a force to the rotating oscillator in the perpendicular direction to the plane, the fourth driving means being disposed in any one of one side and two sides of a surface of the second detecting oscillator parallel to the plane.

14. The angular rate sensor according to claim 11, wherein the vibration generating means comprises third driving means which applies a force to the rotating oscillator in the perpendicular direction to the plane, the third driving means being disposed in any one of one side and two sides of a surface of the first detecting oscillator parallel to the plane;

and fourth driving means which applies a force to the rotating oscillator in the perpendicular direction to the plane, the fourth driving means being disposed in any one of one side and two sides of a surface of the second detecting oscillator parallel to the plane.

15. The angular rate sensor according to claim 12, wherein the vibration generating means comprises third driving means which applies a force to the rotating oscillator in the perpendicular direction to the plane, the third driving means being disposed in any one of one side and two sides of a surface of the first detecting oscillator parallel to the plane;

and fourth driving means which applies a force to the rotating oscillator in the perpendicular direction to the plane, the fourth driving means being disposed in any one of one side and two sides of a surface of the second detecting oscillator parallel to the

16. The angular rate sensor according to claim 10, wherein

each of the first and second driving means comprises:

a plurality of movable-side detecting comb-shaped electrodes bonded to the rotating oscillator; and

a plurality of fixed-side driving comb-shaped electrodes fixed in a way that part of side faces thereof face the movable-side driving comb-shaped electrodes, and

a driving force is generated by applying an electric potential difference between each movable-side driving comb-shaped electrode and the corresponding fixed-side driving comb-shaped electrode.

17. The angular rate sensor according to claim 11, wherein

each of the first and second driving means comprises:

a plurality of movable-side detecting comb-shaped electrodes bonded to the rotating oscillator; and

a plurality of fixed-side driving comb-shaped electrodes fixed in a way that part of side faces thereof face the movable-side driving comb-shaped electrodes, and

a driving force is generated by applying an electric potential difference between each movable-side driving comb-shaped electrode and the corresponding fixed-side driving comb-shaped electrode.

18. The angular rate sensor according to claim 12, wherein

each of the first and second driving means comprises:

a plurality of movable-side detecting comb-shaped electrodes bonded to the rotating oscillator; and

a plurality of fixed-side driving comb-shaped electrodes fixed in a way that part of side faces thereof face the movable-side driving comb-shaped electrodes, and

a driving force is generated by applying an electric potential difference between each movable-side driving comb-shaped electrode and the corresponding fixed-side driving comb-shaped electrode.

19. The angular rate sensor according to claim 13, wherein each of the third and fourth driving means comprises:

a first driving flat electrode disposed so that at least part of the first driving flat electrode faces the surface of the plane of the detecting oscillator parallel to the plane with a gap interposed in between; and

a second driving flat electrode disposed so that at least part of the second driving flat electrode faces the surface of the second detecting oscillator parallel to the plane with a gap interposed in between.

20. The angular rate sensor according to claim 14, wherein each of the third and fourth driving means comprises:

a first driving flat electrode disposed so that at least part of the first driving flat electrode faces the surface of the plane of the detecting oscillator parallel to the plane with a gap interposed in between; and

a second driving flat electrode disposed so that at least part of the second driving flat electrode faces the surface of the second detecting oscillator parallel to the plane with a gap interposed in between.

21. The angular rate sensor according to claim 15, wherein each of the third and fourth driving means comprises:

a first driving flat electrode disposed so that at least part of the first driving flat electrode faces the surface of the plane of the detecting oscillator parallel to the plane with a gap interposed in between; and

a second driving flat electrode disposed so that at least part of the second driving flat electrode faces the surface of the second detecting oscillator parallel to the plane with a gap interposed in between.

22. A multiaxial detection type angular rate sensor comprising a first sensor unit and a second sensor unit which include an angular rate sensor formed into a planar shape and configured to detect an angular rate around a first axis in the plane, the angular rate sensor comprising:

a rotating oscillator rotatably supported in the plane and around the rotational axis in a direction of a second axis perpendicular to the first axis;

vibration generating means which rotationally vibrates the rotating oscillator; and

a first detecting oscillator and a second detecting oscillator which are disposed inside the rotating oscillator and separately on the right side and the left side of the rotational axis, and which are supported as being displaceable in a direction of the second axis, wherein

a first detecting unit and a second detecting unit, which detect vibrations of the respective first and second detecting oscillators in the direction of the second axis due to the Coriolis force, are respectively provided closer to the rotational axis than the first and second detecting oscillators are,

the first sensor unit and the second sensor unit are disposed perpendicular to each other,

the first sensor unit detects an angular rate around the first axis and

the second sensor unit detects an angular rate around the second axis.

23. A multiaxial angular rate sensor according to claim 22, provided with an acceleration detecting function, wherein

the first sensor unit detects acceleration in the direction of the second axis, and

the second sensor unit detects acceleration in a direction of the first axis.