Universal thruster selection logic for spacecraft attitude control
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
B64G-001/26
출원번호
US-0519442
(1995-08-25)
발명자
/ 주소
Ratan Santosh (Lawrenceville NJ) Goodzeit Neil Evan (Princeton NJ)
출원인 / 주소
Martin Marietta Corp. (East Windsor NJ 02)
인용정보
피인용 횟수 :
13인용 특허 :
0
초록▼
A three-axis stabilized spacecraft includes a plurality of primary attitude control thrusters, the torque vectors of which lie in, or parallel to a primary plane. It also includes at least two more secondary attitude control thrusters, the torque vectors of which lie in a secondary plane which is no
A three-axis stabilized spacecraft includes a plurality of primary attitude control thrusters, the torque vectors of which lie in, or parallel to a primary plane. It also includes at least two more secondary attitude control thrusters, the torque vectors of which lie in a secondary plane which is not parallel to the primary plane. The control system produces attitude error signals, which are processed with a PID characteristic to produce impulse demand signals, all in known fashion. The impulse demand signals are transformed into an auxiliary coordinate system, in which two of the three auxiliary axes lie in the primary plane, and the third is orthogonal thereto. One of the secondary thrusters is selected, which has, along the third auxiliary axis, the largest torque magnitude and the same sign as the transformed impulse demand. The augmented impulse demand in the primary plane is determined, and the two primary thrusters are selected whose torque vectors in the primary plane bound the augmented impulse demand. The selected primary thrusters and the selected secondary thruster are fired with a pulse width which provides the desired impulse.
대표청구항▼
A method for attitude control of a spacecraft, said spacecraft having at least five attitude control thrusters located in a manner such that a first set of at least three primary ones of said thrusters have their torque vector directions lying approximately in a primary plane, and the remaining atti
A method for attitude control of a spacecraft, said spacecraft having at least five attitude control thrusters located in a manner such that a first set of at least three primary ones of said thrusters have their torque vector directions lying approximately in a primary plane, and the remaining attitude control thrusters, constituting a set of secondary thrusters, have their torque vector directions lying approximately in a second plane which is nonparallel with said primary plane, said method comprising the steps of: sensing the current attitude of said spacecraft, to produce attitude-representative signals; generating desired attitude signals representing the desired attitude of said spacecraft; taking the difference between said attitude-representative and said desired attitude signals, to produce attitude error signals; applying said attitude error signals to a controller having at least a proportional characteristic, for generating impulse demand signals representing impulse demand along each of three mutually orthogonal principal axes; transforming the components of said impulse demand along said three principal axes into an impulse demand along a set of three mutually orthogonal auxiliary axes, two of which lie in said primary plane, and a third of which is normal to said primary plane; selecting one of said thrusters of said set of secondary thrusters which has, along said third auxiliary axis, a torque component with the same sign as said transformed impulse demand along said third auxiliary axis; calculating augmented impulse demand in said primary plane by [Figure] where: I1 is the component of the transformed impulse demand along the first auxiliary axis; I2 is the component of the transformed impulse demand along the second auxiliary axis; I3 is the component of the transformed impulse demand along the third auxiliary axis; Tt1 is the torque along the first auxiliary axis of the selected secondary thruster; Tt2 is the torque along the second auxiliary axis of the selected secondary thruster; and Tt3 is the torque along the third auxiliary axis of the selected secondary thruster; and the subscript “aug”identifies the augmented impulse demand matrix; selecting first and second adjacent primary thrusters of said set of primary thrusters, said selected adjacent primary thrusters being those whose torque vectors in said primary plane most closely bound said augmented impulse demand in said primary plane; calculating the pulse widths required for said first and second adjacent primary thrusters and said selected secondary thrusters to produce said impulse demand, according to [Figure] where; PWf is the pulse width of the selected first adjacent primary thruster; PWs is the pulse width of the selected second adjacent primary thruster; PWt is the pulse width of the selected secondary thruster; M-1 is the inverse of matrix M, and matrix M is given by [Figure] where the first column of matrix M is the torque vector of the selected first primary adjacent thruster along the first, second and third auxiliary axes, the second column matrix M is the torque vector of the selected second adjacent primary thruster along the first, second and third auxiliary axes, and the third column of matrix M is the torque vector of the selected secondary thruster along the first, second and third auxiliary axes; and applying the calculated pulse widths to said selected first and second primary thrusters and to said selected secondary thruster for torquing said spacecraft for attitude control.
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이 특허를 인용한 특허 (13)
Weigl, Harald J.; Goodzeit, Neil E.; Ratan, Santosh, Attitude determination system for yaw-steering spacecraft.
Koehler, Frederick B.; Danforth, Jeremy C.; Lyman, Ward D.; Langhenry, Mark T.; Summers, Matt H.; Pontius, Paul E.; Pape, Brian M.; Stallings, Jared D.; Villarreal, James K.; Villarreal, Thomas, Satellite with integral thrusters.
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