METHOD AND APPARATUS FOR DECOUPLING ENVIRONMENTAL AND MODAL DEPENDENCIES IN INERTIAL MEASUREMENT DEVICES
A resonant gyroscope apparatus has a decoupling mechanism implemented with spring-like flexure members to effectively isolate an axis-symmetric bulk-acoustic wave (BAW) vibratory gyroscope from its substrate, thereby minimizing the effect that external sources of error have on offset and scale-factor. The spring-like structure enables degeneracy of in-plane resonance modes of the annulus and aids in decoupling the in-plane and out-of-plane resonance modes of the resonant annulus, thereby enabling the mode-matched and/or near mode-matched operation of the structure as a vibratory gyroscope in the pitch, roll and yaw-modes. In various embodiments, the decoupling mechanism may be coupled to either an interior or exterior perimeter of an annulus shaped resonator element of the gyroscope
1 . The resonant apparatus comprising:
a resonant member;
a structure for supporting the resonant member relative to a another surface, and
a decoupling mechanism for flexibly decoupling the resonant member from the support structure.
2 . The apparatus of claim 1 wherein the resonant member has is substantially annulus shaped.
3 . The apparatus of claim 1 wherein the structure for supporting the resonant member comprises an anchor.
4 . The apparatus of claim 3 wherein the anchor is coupled to a substrate.
5 . The apparatus of claim 1 wherein the decoupling mechanism comprises a plurality of springs coupling a perimeter the resonant member to the supporting structure.
6 . The apparatus of claim 5 wherein the plurality of springs are arranged in mirrored pairs about the perimeter the resonant member.
7 . The apparatus of claim 5 wherein each of the springs comprises a flexure member having a first end coupled to the perimeter of the resonant member and a second end coupled the supporting structure.
8 . The apparatus of claim 7 wherein the flexure member has at least one substantially right angle transition between the first end and the second end in an unflexed mode.
9 . The apparatus of claim 7 wherein the flexure member has at least four substantially right angle transitions between the first end and the second end when in an unflexed mode.
10 . The apparatus of claim 7 wherein the flexure member has at least eight substantially right angle transitions between the first end and the second end when in an unflexed mode.
11 . The apparatus of claim 7 wherein the flexure member has at least twelve substantially right angle transitions between the first end and the second end when in an unflexed mode.
12 . The apparatus of claim 1 wherein the decoupling mechanism enables degeneracy of in-plane resonance modes of the resonant member.
13 . A gyroscope apparatus comprising:
a substantially annulus shaped resonator element having a pattern of flexure members extending outward therefrom; and
a structure for supporting the resonant member relative to a another surface, and
wherein each flexure member has a plurality of substantially right angle transitions between first and second ends thereof.
14 . A method of manufacturing a bulk acoustic wave resonator element comprising:
A) forming an annulus shaped resonator element having a perimeter edge;
B) etching a plurality of apertures in the resonator element to collectively define a plurality of springs extending from the perimeter edge, wherein the springs each of the springs comprises a flexure member having a plurality of substantially right angle transitions.
15 . An article of manufacture comprising an annulus shaped resonator element separated from a support structure by a plurality of springs connecting, wherein each of the springs comprises a flexure member having a plurality of substantially right angle transitions between junctures with the annulus shaped resonator element and support structure.
16 . The article of manufacture of claim 15 wherein each of the support structure comprises a plurality of support structures disposed about an exterior perimeter of the annulus shaped resonator element.
17 . The article of manufacture of claim 15 wherein support structure comprises an annulus shaped support structures disposed about an exterior perimeter of the annulus shaped resonator element.
18 . The article of manufacture of claim 15 wherein support structure comprises a central anchor disposed within an interior perimeter of the annulus shaped resonator element, so that the resonator element is axis symmetric about the support structure.
19 . The article of manufacture of claim 15 wherein the plurality of springs are arranged in mirrored pairs.