Flat-pack gyroscope

• US 5,881,598 A
• Filed: 06/27/1997
• Issued: 03/16/1999
• Est. Priority Date: 06/27/1996
• Status: Expired due to Fees

• Current Assignee: Milli Sensor Systems & Actuators, Inc.
• Original Assignee: Milli Sensor Systems & Actuators, Inc.
• Inventors: Sapuppo, Michele, Cardarelli, Donato, Dauwalter, Charles R.
• Primary Examiner(s): Bonck, Rodney H.
• Application Number:
  US08/884,291
• Time in Patent Office: 627 Days
• US Class Current: 74/5.60E
• CPC Class Codes: G01C 19/06 Rotors
• CPC Class Codes: G01C 19/28 Pick-offs, i.e. devices for taking-off an indication of the displacement of the rotor axis
• CPC Class Codes: Y10T 74/1279 Electrical and magnetic
• CPC Class Codes: Y10T 74/1282 with rotor drive
• CPC Class Codes: Y10T 74/1293 Flexure hinges for gyros

Abstract

A flat pack gyroscope fabricated of a number of discrete flat layers, which, when assembled together, accomplish a version of a single degree of freedom, spinning wheel gyroscope.

Claims

1. A single degree of freedom, spinning wheel gyroscope for determining rotation about a gyroscope input axis, comprising:

a fixed case;

a torque summing member mounted within said case by a pair of coaxial flexures, for pivoting on said flexures about an output axis which is transverse to the gyroscope input axis;

a disk encircled by said torque summing member and adapted to rotate about a spin axis which is transverse to both said output axis and the gyroscope input axis;

means for rotating said disk about said spin axis;

means for determining the pivotal position of said torque summing member about said output axis; and

means, responsive to said means for determining the pivotal position of said torque summing member, for determining rotation of said case about the gyroscope input axis.

2. The single degree of freedom gyroscope of claim 1 wherein said gyroscope is constructed of a plurality of discrete layers, and in which said disk is within a discrete layer of said gyroscope.

3. The single degree of freedom gyroscope of claim 2 in which said means for rotating said disk about said spin axis includes disk driving means located in two discrete stator layers each directly adjacent to said discrete layer in which said disk is located.

4. The single degree of freedom gyroscope of claim 3 in which said disk driving means includes motor stators in each of said two discrete stator layers.

5. The single degree of freedom gyroscope of claim 4 in which said motor stators each include means for creating a rotating magnetomotive force on said disk.

6. The single degree of freedom gyroscope of claim 5 in which said means for creating a rotating magnetomotive force includes a multi-phase, multi-pole stator, and means for energizing the stator poles in quadrature to create a rotating electromagnetic field acting upon said disk.

7. The single degree of freedom gyroscope of claim 6 in which said disk is made of magnetic material with relatively high magnetic hysteresis.

8. The single degree of freedom gyroscope of claim 3 in which said means for determining the pivotal position of said torque summing member is partially carried by said two discrete stator layers.

9. The single degree of freedom gyroscope of claim 8 further including two discrete cover layers directly adjacent to said stator layers.

10. The single degree of freedom gyroscope of claim 9 in which said means for determining the pivotal position of said torque summing member is also partially carried by said two discrete cover layers.

11. The single degree of freedom gyroscope of claim 10 in which said stator layers carry capacitive pick-off members, and said cover layers carry capacitive pick-off members directly adjacent to but spaced from said pick-off members on said stator layers, to accomplish capacitive sensing of the distance between adjacent but spaced pick-off members.

12. The single degree of freedom gyroscope of claim 4 further including gas bearing means for supporting said disk as it rotates about said spin axis.

13. The single degree of freedom gyroscope of claim 12 in which said gas bearing means includes grooves in each of said two discrete stator layers, said grooves proximate said disk.

14. The single degree of freedom gyroscope of claim 13 in which said disk is annular, and in which said gas bearing means further includes a cylindrical journal post within the disk annulus central opening, said journal post very close to but not touching said annulus.

15. The single degree of freedom gyroscope of claim 1 in which said flexures have a relatively large spring constant, and a relatively small damping, to accomplish a rate gyroscope in which the angular pivotal deflection of said torque summing member is related to the time rate of change of gyroscope rotation about the input axis.

16. The single degree of freedom gyroscope of claim 1 in which said flexures have a relatively large damping and relatively small spring constant, to accomplish a rate integrating gyroscope in which the angular pivotal deflection of said torque summing member is proportional to the angle of rotation of said gyroscope about the input axis.

17. A single degree of freedom, multiple-layer spinning wheel gyroscope for determining rotation about a gyroscope input axis, comprising:

a central discrete layer comprising a frame carrying an internal mechanical housing member mounted by a pair of coaxial flexures within said frame to rotate about an output axis transverse to the gyroscope input axis, and a central annular disk within said mechanical housing member, made of a magnetic material, and adapted to rotate about a spin axis which is transverse to both said output axis and the gyroscope input axis;

means for rotating said disk about said spin axis, including motor stators located in each of two discrete stator layers each directly adjacent to one side of said central discrete layer in which said disk is located, in which said motor stators each include a multi-phase, multi-pole stator, and means for energizing the stator poles in quadrature to create a rotating electromagnetic field acting upon said disk;

wherein said motor stators are each carried by a stator support member, and in which said stator support members are fixed to said internal mechanical member to create a torque summing member;

two discrete cover layers directly adjacent to said stator layers;

means, carried by said stator support members and said cover layers, for determining the pivotal position of said torque summing member about said output axis; and

means, responsive to said means for determining the pivotal position of said torque summing member, for determining rotation of said case about the gyroscope input axis.

18. A single degree of freedom, multiple-layer, flat-pack spinning wheel gyroscope for determining rotation about a gyroscope input axis, comprising:

a central discrete layer comprising a flat frame carrying an internal mechanical housing member mounted by a pair of coaxial flexures within said frame to rotate about an output axis transverse to the gyroscope input axis, and a central annular disk within said mechanical housing member, made of a magnetic material, and adapted to rotate about a spin axis which is transverse to both said output axis and the gyroscope input axis;

means for rotating said disk about said spin axis, including motor stators located in each of two discrete stator layers each directly adjacent to one side of said central discrete layer in which said disk is located, in which said motor stators each include a multi-phase, multi-pole stator, and means for energizing the stator poles in quadrature to create a rotating electromagnetic field acting upon said disk;

wherein said motor stators are each carried by a stator support member, and in which said stator support members are fixed to said internal mechanical member to create a torque summing member;

flat stator layer external frames surrounding each said stator support member;

mechanical tangs between each said stator layer external frame and said stator support member surrounded by said external frame, to maintain said stator support members fixed during gyroscope assembly;

two discrete flat cover layers directly adjacent to said stator layers;

wherein said stator layer external frames are each fixed to a said cover layer and to said frame of said central layer, to create a fixed gyroscope case;

capacitive pick-off means carried by said stator support members and said cover layers, for determining the pivotal position of said torque summing member about said output axis; and

means, responsive to said capacitive pick-off means for determining the pivotal position of said torque summing member, for determining rotation of said case about the gyroscope input axis.