EP0836073A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
A rate sensor
Assignee: BAE Systems PLC
•
Filing: 1997-10-07
•
Granted: —
•
Expires: 2017-10-07
Abstract
Abstract A rate sensor for sending applied rate on at least two and preferably three axes includes a vibrating structure (6). Means are provided for vibrating the structure (6) in a Cos 2 carrier mode at a Cost 2 frequency. This carrier mode provides the linear momentum components necessary to couple energy into response modes in every geometric plane. Rotation about one or other of the axes in the plane of the vibrating structure will generate Coriolis forces which cause a rocking motion of the vibrating structure (6) about the same axis at the carrier mode frequency. The vibrating structure (6) has a substantially planar substantially ring or hoop like form shaped and dimensioned to match the frequencies of the Cos 2 mode and rocking mode vibrations in the structure (6) resulting in a resonant amplification of the rocking mode vibrations caused by rotations around axes in the plane of the structure (6). Rotation about the third axis normal to the plane of the structure (6) generates Coriolis forces which couple energy into the degenerate Cos 2 response mode. The Cos 2 response and rocking mode vibration amplitudes are proportional to the applied rate and means are provided for detecting the Cos 2 response mode and rocking mode vibration and thereby the applied rate.
Inventors
- 👤 Christopher Paul Fell
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 06:41
CPC Classifications
G; G01; G01P; G01P3/00; G01P3/42; G01P3/44; G01P3/46; G01P3/465; G01C; G01C19/00; G01C19/56; G01C19/567; G01C19/5677; G01P3/02; G01P3/24; B; B01; B01L; B01L2400/00; B01L2400/04; B01L2400/0403; B01L2400/0409; B01L2400/0412
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
150 words
A rate sensor for sensing applied rate on at least two
axes, characterised by including a vibrating structure
(4,6), means for vibrating the structure (4,6) in a Cos
2 carrier mode at a Cos 2 mode frequency such that
rotation about one or other of said at least two axes
(10,11,12) in the plane of the vibrating structure (4,6)
will generate a Coriolis force sufficient to cause a
rocking motion of the vibrating structure about the same
axis at the carrier mode frequency, with the vibrating
structure (4,6) having a substantially planar
substantially ring or hoop-like form shaped and
dimensioned to match the frequencies of the Cos 2 mode
and the rocking mode vibrations in the vibrating
structure to give a resonant amplification of the
rocking motion, which rocking mode vibration is
proportional to the applied rate, and means for
detecting the rocking mode vibration and thereby the
applied rate.
Claim 2
Dependent Claim
18 words
A sensor according to claim 1, wherein the vibrating
structure (4,6) is made of metal or of silicon.
Claim 3
Dependent Claim
36 words
A sensor according to claim 2, wherein the vibrating
structure (4,6) is ring like in form having an outer rim
(7) supported by a plurality of legs (8) extending
substantially radially from a central boss (9).
Claim 4
Dependent Claim
200 words
A sensor according to claim 3, for sensing applied rate
on two axes (10,11), having a substantially planar
ring-like vibrating structure (4,6) made from metal,
wherein the means for vibrating the vibrating structure
in a Cos 2 mode includes an electromagnetic carrier
mode drive element (13) and a capacitive carrier mode
pick off element (14) arranged at 0° and 270°
respectively with respect to the outer rim (7) of the
vibrating structure (6) and located in the plane of the
outer rim (7) radially externally thereof adjacent
points of maximum radial motion of said rim (7) when
vibrating in the Cos 2 mode, and wherein the means for
detecting the rocking mode vibration includes an x axis
electromagnetic drive element (15), an x axis capacitive
pick off element (16), a y axis electromagnetic drive
element (17) and a y axis capacitive pick off element
(18), located adjacent to the outer rim (7) in
superimposed relationship therewith at a perpendicular
spacing therefrom, with the y axis pick off element
(18), x axis drive element (15), y axis drive element
(17) and x axis pick off element (16) being arranged at
0°, 90°, 180° and 270° respectively around the outer rim
(7).
Claim 5
Dependent Claim
131 words
A sensor according to claim 4, for sensing applied rate
on three axes (10,11,12), wherein the means for
vibrating the vibrating structure (6) additionally
includes an electromagnetic response mode drive element
(19) and a capacitive response mode pick off element
(20) located in the plane of the outer rim (7) of the
vibrating structure (6) adjacent to the points of
maximum radial movement for the outer rim (7) when
vibrating in a response mode, with the response mode
drive element (19) and pick off element (20) being
arranged at 135° and 225° respectively with respect to
the outer rim (7) of the vibrating structure and located
in the plane of the outer rim radially externally
thereof, to sense rotation about the axis normal to the
plane of the vibrating structure (6).
Claim 6
Dependent Claim
24 words
A sensor according to claim 3, wherein the outer rim (7)
is substantially circular in plan view or is
substantially rectangular in plan view.
Claim 7
Dependent Claim
22 words
A sensor according to any one of claims 2 to 6, wherein
the vibrating structure (6) is made of a nickel-iron
alloy.
Claim 8
Dependent Claim
211 words
A sensor according to claim 3, for sensing applied rate
on two axes, having a substantially planar,
substantially ring-like vibrating structure (6) made
from silicon, wherein the means for the vibrating
structure in a Cos 2 mode includes two electrostatic
carrier mode drive elements (22) and two electrostatic
carrier mode pick off elements (23) arranged with the
drive elements (22) at 0° and 180° and the pick off
elements (23) at 90° and 270° respectively with respect
to the outer rim (7) of the vibrating structure (6) and
located radially externally of the outer rim adjacent
points of maximum radial motion of the outer rim when
vibrating in the Cos 2 mode, and wherein the means for
detecting the rocking mode vibration includes an x axis
electrostatic drive element (24), an x axis
electrostatic pick off element (25), a y axis
electrostatic drive element (26) and a y axis
electrostatic pick off element (27) located adjacent the
outer rim (7) in superimposed relationship therewith at
a perpendicular spacing therefrom, with the y axis drive
element (26), the x axis pick off element (25), the y
axis pick off element (27) and the x axis drive element
(24) being arranged at 0°, 90°, 180° and 270°,
respectively around the outer rim (7).
Claim 9
Dependent Claim
136 words
A sensor according to claim 8, for sensing applied rate
on three axes, wherein the means for vibrating the
vibrating structure (6) additionally includes two
electrostatic z axis response mode drive elements (30)
and two electrostatic z axis response mode pick off
elements (31) located in the plane of the outer rim (7)
of the vibrating structure (6) radially externally
thereof adjacent points of maximum radial movement for
the outer rim when vibrating in a response mode, with
the first z axis response mode drive element (30), the
first z axis response mode pick off element (31), the
second z axis response mode drive element (30) and the
second z axis response mode pick off element (31) being
arranged at 45°, 135°, 225° and 315° respectively around
the outer rim (7) of the vibrating structure (6).
Claim 10
Dependent Claim
42 words
A sensor according to claim 9, wherein the outer rim (7)
is substantially circular in plan view with the outer
rim and legs (8) being suspended above an insulated
substrate layer by means of the central boss (9) which
is mounted thereon.
Claim 11
Dependent Claim
71 words
A sensor according to any one of claims 3 to 10, wherein
the vibrating structure (6) is dimensioned to match the
frequencies of the Cos 2 and rocking mode vibrations by
controlled removal of material from the edge of the
outer rim (7) to modify the mass thereof or by
controlled removal of material from the neutral axis of
the outer rim to modify the stiffness of the outer rim
(7).
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.