IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0574902
(2009-10-07)
|
등록번호 |
US-8798816
(2014-08-05)
|
우선권정보 |
FR-08 06076 (2008-10-31) |
발명자
/ 주소 |
|
출원인 / 주소 |
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
2 인용 특허 :
5 |
초록
▼
The method for unloading the inertia wheels of a spacecraft comprising three references axes X, Y, Z, the axis Z corresponding to a pointing direction, consists in inverting the direction of accumulation of the angular momentum in the wheels by automatic rotational flipping of the spacecraft about t
The method for unloading the inertia wheels of a spacecraft comprising three references axes X, Y, Z, the axis Z corresponding to a pointing direction, consists in inverting the direction of accumulation of the angular momentum in the wheels by automatic rotational flipping of the spacecraft about the axis Z, the pointing direction remaining fixed. The method has application to the field of satellites or of interplanetary probes.
대표청구항
▼
1. A method for unloading inertia wheels of a spacecraft, the spacecraft comprising three reference axes X, Y, Z, the Z axis corresponding to a pointing direction and the spacecraft having a capacity to accumulate an onboard angular momentum in the inertia wheels up to a maximum loading value corres
1. A method for unloading inertia wheels of a spacecraft, the spacecraft comprising three reference axes X, Y, Z, the Z axis corresponding to a pointing direction and the spacecraft having a capacity to accumulate an onboard angular momentum in the inertia wheels up to a maximum loading value corresponding to a maximum angular speed, said method comprising, for unloading the inertia wheels of the spacecraft along the three axes X, Y, Z comprising: choosing a threshold value Hs for the onboard angular momentum in the inertia wheels, said threshold value being less than the maximum loading value, and,flipping the spacecraft only about the Z axis, while a pointing direction remains fixed, when the onboard angular momentum in the inertia wheels reaches or exceeds said threshold value, the flipping inverting the direction of accumulation of the angular momentum in the inertia wheels. 2. The method according to claim 1, further comprising: choosing a reference onboard angular momentum vector {right arrow over (H)}0,periodically measuring the angular speed of each inertia wheel,for each speed measurement, calculating an onboard angular momentum vector {right arrow over (H)}i and deducing therefrom an accumulated angular momentum Hi equal to a difference, in modulus, between the onboard angular momentum vector {right arrow over (H)}i and the reference onboard angular momentum vector {right arrow over (H)}0,comparing the accumulated angular momentum Hi with the threshold value Hs,when the accumulated angular momentum Hi is greater than the threshold value Hs, taking a decision on the triggering of a flipping manoeuvre making it possible to unload the wheels, then triggering an automatic manoeuvre for rotational flipping of the spacecraft by a predetermined angle about the axis Z, the pointing direction remaining fixed,wherein the rotational flipping manoeuvre of the spacecraft is carried out by at least one inertia wheel. 3. The method according to claim 2, wherein the decision on triggering the flipping manoeuvre is taken if Hi increases between two successive measurements. 4. The method according to claim 1, comprising flipping the spacecraft by an angle equal to 180° about the axis Z. 5. The method according to claim 2, wherein the triggering of the rotational flipping manoeuvre is authorized in a prior step of authorizing the flipping manoeuvre allowing the unloading when the spacecraft is in a predetermined position on a trajectory. 6. The method according to claim 5, wherein the predetermined position corresponds to the spacecraft passing over a geographic land zone of low population density or when the spacecraft passes into a zone where it is night. 7. A system for a spacecraft comprising at least one inertia wheel, the spacecraft having a capacity to accumulate an onboard angular momentum in the at least one inertia wheel up to a maximum loading value, said system for unloading the at least one inertia wheel, said system comprising: at least one onboard computer for storing a threshold value Hs for the onboard angular momentum in the at least one inertia wheel, said threshold value being less than a maximum loading value, and,the at least one onboard computer triggering an automatic manoeuvre for rotational flipping of the spacecraft by a predetermined angle only about a Z axis corresponding to a pointing direction, the pointing direction remaining fixed, when the onboard angular momentum in the at least one wheel reaches or exceeds said threshold value, the angle being chosen so as to invert the direction of accumulation of the angular momentum in the at least one inertia wheel. 8. The unloading system according to claim 7, further comprising at least one speed sensor mounted on the inertia wheel, the at least one onboard computer computing the angular momentum Hi accumulated by the inertia wheel corresponding to the measured speed, the at least one onboard computer comparing the angular momentum accumulated by the wheel with a previously chosen threshold value Hs for triggering the unloading of the wheels, and the at least one onboard computer deciding on triggering a flipping manoeuvre of the spacecraft when the value of the angular momentum accumulated by the wheel is greater than the threshold value. 9. A spacecraft comprising at least one inertia wheel and one axis Z corresponding to a pointing direction and comprising a system for unloading the inertia wheel according to claim 7.
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