Rotation rate sensor

• US 8,365,595 B2
• Filed: 03/28/2008
• Issued: 02/05/2013
• Est. Priority Date: 06/29/2007
• Status: Expired due to Fees

• Current Assignee: Northrop Grumman Litef Gmbh (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Litef Gmbh (Northrop Grumman Corporation)
• Inventors: Geiger, Wolfram, Leinfelder, Peter, Spahlinger, Guenter, Bartholomeyczik, Julian
• Primary Examiner(s): Kwok, Helen C.
• Application Number:
  US12/451,998
• Publication Number:
  US 20100139399A1
• Time in Patent Office: 1,775 Days
• Field of Search: 735/041.4, 735/041.2, 735/041.6, 735/040.2, 735/040.4
• US Class Current: 73/504.14
• CPC Class Codes: G01C 19/574 the devices having two sensing masses in anti-phase motion

Abstract

A rotation rate sensor comprises a substrate and two structures which move relative to the substrate on a design plane (x-y), with the two moving structures being coupled to form a coupled structure such that the coupled structure has a first oscillation mode with antiphase deflections of the moving structures in a first direction (x) on the design plane (x-y) as excitation mode. The coupled structure has a second oscillation mode as a detection mode which is excited by Coriolis accelerations when the first oscillation mode is excited and on rotation about a sensitive axis (z) of the rotation rate sensor. The sensitive axis is at right angles to the design plane (x-y), and the coupled structure is designed such that, subject to optimal preconditions, it does not have any oscillation mode which can be excited by linear accelerations of the rotation rate sensor in a direction parallel to the second axis.

Claims

1. A rotation rate sensor having a substrate and two multipart individual structures which can move relative to the substrate on a design plane wherein the two individual structures are coupled to form a coupled structure such that

the coupled structure has a first oscillation mode with antiphase deflections of the two moving individual structures in a first direction on the design plane as an excitation mode,

the coupled structure has a second oscillation mode as a detection mode, which is excited by Coriolis accelerations when the first oscillation mode is excited and during rotation about a sensitive axis, which is at right angles to the design plane of the rotation rate sensor, characterized in that

a rotating spring element is provided which is soft for torsion about an axis of symmetry which is parallel to the sensitive axis, is stiff for all other loads and couples the two individual structures to one another, such that parts of the individual structures carry out a common rotary oscillation about the axis of symmetry, wherein the detection mode comprises antiphase linear oscillation, transferred from the rotary oscillation, of parts of the two individual structures along a second direction, which is at right angles to the first direction.

2. The rotation rate sensor as claimed in claim 1 characterized in that

the rotating spring element comprises bending beams and an anchorage of the substrate, and is formed symmetrically about the axis of symmetry.

3. The rotation rate sensor as claimed in claim 1, characterized in that

the individual structures have excitation units and sample masses, wherein the excitation units can move only in the first direction and are coupled via coupling spring structures, and the sample masses are coupled via y spring elements to the excitation units,

and the y spring elements are stiff in the first direction and parallel to the sensitive axis, and are soft in the second direction, and

the sample masses are connected via x rotating spring elements to the rotating spring element, wherein the x rotating spring elements have an axis of symmetry which is parallel to the sensitive axis, are in each case provided between the individual structures and the rotating spring element, and are soft in the first direction and for torsion about the axis of symmetry, and stiff for all other loads.

4. The rotation rate sensor as claimed in claim 2, characterized in that

the individual structures comprise excitation units, coriolis elements and detection units, wherein the excitation units are coupled via coupling spring structures and the detection units are coupled via the rotating spring element and x rotating spring elements, and wherein the Coriolis elements are connected via y spring elements to the excitation units, and the detection units are connected via x spring elements to the Coriolis elements, and in that the individual structures have further y spring elements, by means of which the detection units are anchored on the substrate, wherein the further y spring elements are soft in the second direction, and are stiff for all other loads, wherein the x rotating spring elements have an axis of symmetry which is parallel to the sensitive axis, are in each case provided between the individual structures and the rotating spring element, and are soft in the first direction and for torsion about the axis of symmetry, and stiff for all other loads.

5. The rotation rate sensor as claimed in claim 1,

characterized in that

the detection mode is a mixed form of the antiphase linear oscillation of parts of the two individual structures along the second direction and

of the rotary oscillation of other parts of the two individual structures about the sensitive axis.

6. The rotation rate sensor as claimed in claim 5, characterized in that

the individual structures comprise excitation units, Coriolis elements and detection units, wherein the Coriolis elements are connected via y spring elements to the excitation units, the excitation units are coupled via coupling spring structures, and the detection units are coupled via the rotating spring element, and

in that x rotating spring elements, which have an axis of symmetry which is parallel to the sensitive axis, are in each case provided between the Coriolis elements and the detection units, wherein the x rotating spring elements are soft in the first direction and for torsion about the axis of symmetry, and are stiff for all other loads.

7. The rotation rate sensor as claimed in claim 1, characterized in that

the individual structures have force transmitters for excitation of the excitation mode.

8. The rotation rate sensor as claimed in claim 1, characterized in that the individual structures have taps for the excitation mode.

9. The rotation rate sensor as claimed in claim 1, characterized in that the individual structures have taps for detection of the detection mode.

10. The rotation rate sensor as claimed in claim 9 characterized in that

the taps for detection of the detection mode are plate capacitor arrangements.

11. The rotation rate sensor as claimed in claim 9, characterized in that

the taps for detection of the detection mode are comb drives.

12. The rotation rate sensor as claimed in claim 1, characterized in that the individual structures have force tansmitters for resetting the detection mode.

13. The rotation rate sensor as claimed in claim 1, characterized in that

tuning electrodes are provided, in order to tune a resonant frequency of the individual structures.