Cross plane wide-gap motor system for gimbal

• US 20050225189A1
• Filed: 12/15/2004
• Published: 10/13/2005
• Est. Priority Date: 02/21/2003
• Status: Active Grant

• Current Assignee: Allan Alfred Voigt, Che Ram Souza Voigt, Chet Alister Johnston, John Mark Speicher
• Original Assignee: Allan Alfred Voigt, Che Ram Souza Voigt, Chet Alister Johnston, John Mark Speicher
• Inventors: Speicher, John Mark, Voigt, Allan Alfred, Voigt, Che Ram Souza, Johnston, Chet Alister
• Granted Patent: US 7,190,097 B2
• Time in Patent Office: Days
• US Class Current: 310/112
• CPC Class Codes: G01C 19/30 Erection devices, i.e. devices for restoring rotor axis to a desired position for instrument indicating the vertical G01C19/46
• CPC Class Codes: Y10T 74/1254 by motor torque
• CPC Class Codes: Y10T 74/1282 with rotor drive

Abstract

An apparatus for the control and alignment of a sensor on a moving vehicle is provided that includes a gimbal ball supported by an outer axis structure and adapted to pivot about an outer elevation axis and about an outer azimuth axis. The outer axis structure is mounted to a vehicle. An inner axis structure includes a cardan shaft that is provided in the ball and is used to support a payload. An inner elevation axis passes through the cardan shaft. The payload is moved about inner pitch inner roll and inner yaw axes over a limited range of motion by the use of a plurality of permanent magnet wide-gap motors that are disposed on the plane of the cardan shaft and maximally away from the yaw axis in the ball. The motors are adapted to each urge the payload to move in two perpendicular axes, depending upon the current that is applied through conductors which pass through a flux field. Control circuitry is used to energize the motors in any desired combination to produce motion in roll, pitch, or yaw.

Claims

1. A motor system adapted for use with a gimbal ball wherein said gimbal ball is supported by an outer axis structure that includes means for providing for the motion of said gimbal ball about an external elevation axis and about an external azimuth axis, comprising:

at least three motors that are separated with respect to each other, and wherein each of said motors is disposed proximate a common plane, said common plane passing through said gimbal ball, and wherein each of said motors is disposed in said gimbal ball away from a yaw axis of said gimbal ball, and wherein a portion of each of said motors is attached to said gimbal ball and a remaining portion thereof is attached to a payload that is disposed in said gimbal ball, and wherein each of said motors is adapted to displace said payload with respect to said gimbal ball.

2. The motor system of claim 1 wherein said motors include wide gap motors.

3. The motor system of claim 1 wherein said gimbal ball includes a cardan axis and wherein said cardan axis is disposed within said common plane.

4. The motor system of claim 3 wherein said cardan axis includes said means for providing for the motion of said payload about an internal elevation axis.

5. The motor system of claim 1 wherein said motors include permanent magnet wide-gap motors.

6. The motor system of claim 5 wherein each of said wide-gap motors includes magnetic torque motor, and wherein each of said magnetic torque motors includes a pair of permanent magnets that are disposed in a spaced apart relationship whereby a magnetic flux path is formed intermediate said pair of permanent magnets and wherein said portion of each of said motors that is attached to said gimbal ball includes said pair of permanent magnets, and wherein each_ of said wide-gap magnetic torque motors includes a portion of a conductor that is disposed within said magnetic flux path and wherein said remaining portion thereof that is attached to a payload includes said conductor and wherein said payload is supported by a cardan shaft and wherein when a sufficient current is passed through said conductor, a force is experienced by said conductor that is sufficient to displace said payload with respect to said gimbal ball.

7. The motor system of claim 6 wherein each of said magnetic torque motors includes a second pair of permanent magnets that are disposed in a spaced apart relationship wherein a second magnetic flux path is formed intermediate said second pair of permanent magnets, and wherein each of said second pair of permanent magnets is attached to said gimbal ball, and wherein said conductor includes an extension that is disposed within said second magnetic flux path.

8. The motor system of claim 7 wherein said second pair of permanent magnets include a polarity that is opposite a polarity of said pair of permanent magnets and wherein said extension includes a direction of a current flow through said second magnetic flux path that is opposite a direction of said current flow through said magnetic flux path and wherein when a current is passed through said conductor, a second force is experienced by said extension and wherein said second force aligns with a direction of said first force that is simultaneously experienced by a portion of said conductor that is disposed in said magnetic flux path.

9. The motor system of claim 6 wherein said magnetic flux path that is formed intermediate said pair of permanent magnets includes a substantially uniform magnetic field.

10. The motor system of claim 9 wherein magnetic flux path that is formed intermediate said pair of permanent magnets includes a distance that is sufficient to permit the movement of said conductor therein.

11. The motor system of claim 10 wherein said distance is sufficient to permit the movement of said conductor sufficient to displace said payload at least two degrees of arc.

12. The motor system of claim 10 wherein said distance is sufficient to permit the movement of said conductor sufficient to displace said payload in said gimbal ball in roll.

13. The motor system of claim 10 wherein said distance is sufficient to permit the movement of said conductor sufficient to displace said payload in said gimbal ball in pitch.

14. The motor system of claim 10 wherein said distance is sufficient to permit the movement of said conductor sufficient to displace said payload in said gimbal ball in yaw.

15. The motor system of claim 6 including means for providing a reference sufficient to sense a position of said payload.

16. The motor system of claim 15 wherein said means for providing a reference includes an inertial measurement unit.

17. The motor system of claim 16 wherein said inertial measurement unit is configured to provide a signal to a control circuit, and wherein said control circuit is adapted to generate a current through said conductor in any of said plurality of motors that is sufficient to displace said payload.

18. The motor system of claim 17 wherein said control circuit is adapted to determine from said signal a magnitude of error and a direction away from a preferred direction that said payload is oriented, and wherein said control circuit is adapted to generate a current through said conductor in any of said motors that is sufficient to provide a correction thereof.

19. The motor system of claim 18 wherein said control circuit is adapted to generate a current simultaneously through a plurality of said conductors in at least two of said motors that is sufficient to provide a correction thereof.

20. The motor system of claim 6 wherein said magnetic torque motors include four magnetic torque motors.

21. The motor system of claim 20 wherein each of said four magnetic torque motors is adapted to displace said conductors along two perpendicular axes.

22. The motor system of claim 21 wherein said two perpendicular axes are adapted to urge said payload about a roll, pitch, and yaw axis.

23. The motor system of claim 20 wherein two of said four magnetic torque motors are disposed in a pair, said pair being disposed in a maximally spaced-apart orientation and on an opposite side of said gimbal ball, whereby a balanced torque is applied to said payload when an equal magnitude force is applied to each motor of said pair.

24. The motor system of claim 6 wherein each of said magnetic torque motors includes a second pair of permanent magnets that are disposed in a spaced apart relationship and parallel with respect to said pair of permanent magnets and wherein a second magnetic flux path is formed intermediate said second pair of permanent magnets, and wherein each of said second pair of permanent magnets is attached to said gimbal ball, and wherein said conductor includes an extension that is disposed within said second magnetic flux path, and wherein subsequent to said sufficient current being applied through said conductor, a first force vector is generated by said pair of permanent magnets and is applied to said conductor and wherein a second force vector is generated by said second pair of permanent magnets and is applied to said conductor and wherein said first force vector is additive with respect to said second force vector.

25. A method for increasing the rate of slew for a yaw axis of a gimbal, including the steps of:

(a) providing a motor system adapted for use with a gimbal ball wherein said gimbal ball is supported by an outer axis structure that includes means for providing for the motion of said gimbal ball about an external elevation axis and about an external azimuth axis, and including at least three motors that are oppositely disposed with respect to each other, and wherein each of said motors is disposed proximate a common plane, said common plane passing through said gimbal ball, and wherein each of said motors is disposed in said gimbal ball distally away from a yaw axis of said gimbal ball, and wherein a portion of each of said motors is attached to said gimbal ball and a remaining portion thereof is attached to a payload that is disposed in said gimbal ball, and wherein each of said motors is adapted to displace said payload about said yaw axis with respect to said gimbal ball; and

(b) slewing said gimbal ball about said yaw axis.