System and method for managing momentum accumulation
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
B64G-001/26
B64G-001/28
B64G-001/24
출원번호
US-0461415
(2014-08-17)
등록번호
US-9428285
(2016-08-30)
발명자
/ 주소
Mansour, Sadek W.
Haskell, John D.
Mactavish, Andrew I.
출원인 / 주소
The Boeing Company
대리인 / 주소
Walters & Wasylyna LLC
인용정보
피인용 횟수 :
0인용 특허 :
12
초록▼
A system for managing momentum accumulation of a spacecraft in orbit may include a reaction wheel assembly for controlling an attitude of a body of a spacecraft, the body defining at least one face, and absorbing momentum, a plurality of arcjet thrusters coupled to the face to generate thrust, and a
A system for managing momentum accumulation of a spacecraft in orbit may include a reaction wheel assembly for controlling an attitude of a body of a spacecraft, the body defining at least one face, and absorbing momentum, a plurality of arcjet thrusters coupled to the face to generate thrust, and a control processor coupled to the plurality of arcjet thrusters for controlling the thrust, wherein actuation of each arcjet thruster of the plurality of arcjet thrusters is configured to produce a net momentum accumulation in the reaction wheel assembly that is below a momentum saturation point of the reaction wheel assembly.
대표청구항▼
1. A system for managing momentum accumulation of a spacecraft in orbit, said spacecraft comprising a body defining at least one face, said system comprising: a reaction wheel assembly for controlling an attitude of said body and absorbing momentum;a plurality of arcjet thrusters coupled to said fac
1. A system for managing momentum accumulation of a spacecraft in orbit, said spacecraft comprising a body defining at least one face, said system comprising: a reaction wheel assembly for controlling an attitude of said body and absorbing momentum;a plurality of arcjet thrusters coupled to said face to generate thrust; anda control processor coupled to said plurality of arcjet thrusters for controlling said thrust, wherein said control processor is configured to: actuate at least one of said plurality of arcjet thrusters to generate a first thrust, said first thrust generating a first directional component of momentum about an axis of momentum; andactuate at least two of said plurality of arcjet thrusters to generate a second thrust, said second thrust generating a second directional component of momentum about said axis of momentum opposite to said first directional component of momentum,wherein a net momentum accumulated in said reaction wheel in response to said first thrust and said second thrust is maintained below a momentum saturation point of said reaction wheel assembly. 2. The system of claim 1 wherein said net momentum is zero. 3. The system of claim 1 further comprising a power conditioning unit coupled to said plurality of arcjets, wherein said power conditioning unit is configured to control a discrete power level of said each arcjet thruster. 4. The system of claim 3 wherein said plurality of arcjet thrusters comprises: a first arcjet thruster comprising a first discrete power level controllable by said power conditioning unit; anda second arcjet thruster comprising a second discrete power level controllable by said power conditioning unit;wherein said first arcjet thruster and said second arcjet are opposite one another and equidistant from an axis of momentum, andwherein said first discrete power level and said second discrete power level are defined to balance said net momentum about said axis of momentum. 5. The system of claim 1 wherein said plurality of arcjet thrusters comprises: a first arcjet thruster comprising a first timing of firing controllable by said control processor; anda second arcjet thruster comprising a second timing of firing controllable by said control processor,wherein said first arcjet thruster and said second arcjet are opposite one another and equidistant from an axis of momentum, andwherein said first timing of firing and said second timing of firing are defined to balance said net momentum about said axis of momentum. 6. The system of claim 5 wherein said plurality of arcjet thrusters further comprises: a third arcjet thruster comprising a third timing of firing controllable by said control processor; anda fourth arcjet thruster comprising a fourth timing of firing controllable by said control processor,wherein said axis of momentum is a first axis of momentum,wherein said third arcjet thruster and said fourth arcjet thruster are opposite one another and equidistant from a second axis of momentum, andwherein said third timing of firing and said fourth timing of firing are defined to balance said net momentum about said second axis of momentum. 7. The system of claim 6 wherein said first timing of firing, said second timing of firing, said third timing of firing, and said fourth timing of firing are defined to balance said net momentum about both said first axis of momentum and said second axis of momentum. 8. A method for managing momentum accumulation of a spacecraft in orbit, said method comprising: actuating, by way of a control processor, at least one of a plurality of arcjet thrusters to generate a first thrust, said first thrust generating a first directional component of momentum about an axis of momentum;actuating, by way of said control processor, at least two of said plurality of arcjet thrusters to generate a second thrust, said second thrust generating a second directional component of momentum about said axis of momentum opposite to said first directional component of momentum;accumulating momentum in a reaction wheel assembly in response to said first thrust and said second thrust; and maintaining a net momentum accumulation in said reaction wheel assembly below a momentum saturation point of said reaction wheel assembly. 9. The method of claim 8 further comprising modulating a power level of said plurality of arcjet thrusters by changing said power level of at least one arcjet thruster of said at least two of said plurality of arcjet thrusters to balance said momentum accumulated in said reaction wheel assembly about at least one axis of momentum. 10. The method of claim 8 further comprising modulating a timing of firing of said plurality of arcjet thrusters by at least one of: changing a firing start time of at least one arcjet thruster of said at least two of said plurality of arcjet thrusters to balance said momentum accumulated in said reaction wheel assembly about at least one axis of momentum;changing a firing stop time of said at least one arcjet thruster of said at least two of said plurality of arcjet thrusters to balance said momentum accumulated in said reaction wheel assembly about at least one axis of momentum; andchanging a firing duration of said at least one arcjet thruster of said at least two of said plurality of arcjet thrusters to balance said momentum accumulated in said reaction wheel assembly about at least one axis of momentum. 11. The method of claim 8 further comprising: generating a combined estimate torque resulting from actuation of said plurality of arcjet thrusters required to balance said net momentum accumulation in said reaction wheel assembly; anddetermining at least one of a power level and a timing of firing of said plurality of arcjet thrusters to generate said combined torque estimate. 12. The method of claim 11 further comprising: determining an error represented by a non-zero net momentum accumulation in said reaction wheel assembly; andrefining modulation of at least one of said power level and said timing of firing of said plurality of arcjet thrusters to balance said net momentum accumulation in said reaction wheel assembly. 13. A method for managing momentum accumulation of a spacecraft in orbit, said method comprising: actuating, by way of a control processor, a first arcjet thruster to generate a first thrust;increasing momentum accumulated in a reaction wheel assembly in response to a first directional component of momentum about an axis of momentum generated by said first thrust;actuating, by way of said control processor, a second arcjet thruster to generate a second thrust; anddecreasing said momentum accumulated in said reaction wheel assembly in response to a second directional component of momentum about said axis of momentum generated by said second thrust,wherein a net momentum accumulation in said reaction wheel assembly is below a momentum saturation point of said reaction wheel assembly. 14. The method of claim 13 further comprising: operating said first arcjet thruster at a first discrete power level; andoperating said second arcjet thruster at a second discrete power level,wherein said first discrete power level and said second discrete power level are defined by at least one of a maximum momentum threshold and a minimum momentum threshold about said axis of momentum to balance said net momentum accumulation about said axis of momentum. 15. The method of claim 14 further comprising setting said second discrete power level to be higher than said first discrete power level when a first directional component of momentum about said axis of momentum generated by said first arcjet thruster is greater than said maximum momentum threshold. 16. The method of claim 14 further comprising setting said first discrete power level to be higher than said second discrete power level when a second directional component of momentum about said axis of momentum generated by said second arcjet thruster is greater than said maximum momentum threshold. 17. The method of claim 14 further comprising setting said first discrete power level to be equal to said second discrete power level when said a directional component of momentum about said axis of momentum generated by first arcjet and said second arcjet thruster is less than said minimum momentum threshold. 18. The method of claim 13 further comprising: operating said first arcjet thruster at a first firing timing; andoperating said second arcjet thruster at a second firing timing,wherein said first firing timing and said second firing timing are defined to balance said net momentum accumulation about said axis of momentum. 19. The method of claim 13 wherein said axis of momentum is a first axis of momentum, and wherein said method further comprises: actuating a third arcjet thruster to generate a third thrust;increasing said momentum accumulation in said reaction wheel assembly in response to a first directional component of momentum about a second axis of momentum;actuating a fourth arcjet thruster to generate a fourth thrust; anddecreasing said momentum accumulation in said reaction wheel assembly in response to a second directional component of momentum about said second axis of momentum,wherein said net momentum accumulation in said reaction wheel assembly is below said momentum saturation point of said reaction wheel assembly. 20. The method of claim 19 further comprising: operating said first arcjet thruster at a first firing timing;operating said second arcjet thruster at a second firing timing;operating said third arcjet thruster for a third firing duration; andoperating said fourth arcjet thruster for a fourth firing duration,wherein said first firing timing, said second firing timing, said third firing duration and said fourth firing duration are defined to balance said net momentum accumulation about said first axis of momentum and said second axis of momentum. 21. The method of claim 19 further comprising: generating a first estimate torque resulting from actuation of said first arcjet thruster, a second estimate torque resulting from actuation of said second arcjet thruster, a third estimate torque resulting from actuation of said third arcjet thruster and a fourth estimate torque resulting from actuation of said fourth arcjet thruster required to maintain said net momentum accumulation in said reaction wheel assembly below said momentum saturation point of said reaction wheel assembly; anddetermining at least one of a power level and a timing of firing for said first arcjet thruster, said second arcjet thruster, said third arcjet thruster and said fourth arcjet thruster to generate said first estimate torque, said second estimate torque, said third estimate torque and said fourth estimate torque. 22. The method of claim 19 further comprising: determining a first actual torque resulting from actuation of said first arcjet thruster;determining a second actual torque resulting from actuation of said second arcjet thruster;determining a third actual torque resulting from actuation of said third arcjet thruster;determining a fourth actual torque resulting from actuation of said fourth arcjet thruster; andrefining at least one of a power level and a timing of firing for at least one of said first arcjet thruster, said second arcjet thruster, said third arcjet thruster and said fourth arcjet thruster to maintain said net momentum accumulation in said reaction wheel assembly below said momentum saturation point of said reaction wheel assembly.
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이 특허에 인용된 특허 (12)
Chan Fred N. (Atherton CA) Reimche Wallace E. (Saratoga CA), Autonomous stationkeeping for three-axis stabilized spacecraft.
Adsit Rhys (Milpitas CA) Liu Tung (Union City CA) Chan Fred N. T. (Atherton CA) Weyandt ; Jr. Charles J. (Yardley PA) Tilley Scott (Belmont CA) Bayloca Michel (Menlo Park CA), Control system and method for spacecraft attitude control.
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