Elementary Magnetic Attitude Control System

Stickler, A. C.; Alfriend, Kyle T.

doi:10.2514/3.57089

Cited by 207 publications

(76 citation statements)

References 7 publications

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“…Otherwise, there exists precession in both roll and yaw directions. But in the actual practice, the decoupling is dispensablesince the control scheme includes magnetic control besides wheel control (Stickler & Alfriend, 1974). (Tian et al, 2001;Qian, 2002) analyze the ACS stability of spacecraft with angular momentum exchange device as actuator, and demonstrate that the introduction of magnetic unloading control can damp precession motion of the spacecraft effectively, which is the main reason why it is dispensable to decouple along roll and yaw channel.…”

Section: Attitude Control Of Three-axis Stabilized Spacecraft With Momentioning

confidence: 99%

Optimal Control Techniques for Spacecraft Attitude Maneuvers

Zhang¹,

Qian²,

Zhang³

2011

Advances in Spacecraft Technologies

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Section: Attitude Control Of Three-axis Stabilized Spacecraft With Momentioning

confidence: 99%

Optimal Control Techniques for Spacecraft Attitude Maneuvers

Zhang¹,

Qian²,

Zhang³

2011

Advances in Spacecraft Technologies

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“…따 라서 위성이 3축 자세안정화가 가능한 상태가 되 게 먼저 초기 각속도를 원하는 각속도가 되도록 제어해야 하며, 이를 디텀블링(detumbling) 제어 또는 초기자세획득(initial attitude acquisition) 이 라고 한다. 디텀블링 제어를 위해서 일반적으로 자기토커를 이용하는 B-dot 제어기(controller)가 사용되고 있다 [3,4]. B Sidi, M., "Spacecraft Dynamics and…”

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Rapid Initial Detumbling Strategy for Micro/Nanosatellite with Pitch Bias Momentum System

2006

Journal of the Korean Society for Aeronautical & Space Scie

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When a satellite separates from the launch vehicle, an initial high angular rate or a tip-off rate is generated. B-dot logic is generally used for controlling the initial tip-off rate. However, it has the disadvantage of taking a relatively long time to control the initial tip-off rate. To solve this problem, this paper suggests a new detumbling control method to be able to adapt to micro/nanosatellite with the pitch bias momentum system.Proposed detumbling method was able to control the angular rate within 20 minutes which is significantly reduced compared to conventional methods. Since the previous wheel start-up method cannot be used if the detumbling controller proposed by this paper is used, a method is also proposed for bringing up the momentum wheel speed to nominal rpm while maintaining stability in this paper. The performance of the method is compared and verified through simulation. The overall result shows much faster control time compared to the conventional methods, and achievement of the nominal wheel speed and 3-axes stabilization while maintaining stability.

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“…The technique utilizes the coupling action between the geomagnetic field and the magnetic dipole moment induced either by three or two magnetic torquers on-board the satellite. McElvain [13] and Stickler and Alfriend [14] proposed a control equation which was later became the standard for wheel unloading control law that uses magnetic control torque. The momentum unloading strategy was designed such that the produced counter torque is a function of the excess momentum to be removed.…”

Section: Introductionmentioning

confidence: 99%

Control torque generation of a CMG-based small satellite with MTGAC system: a trade-off study

Salleh

Suhadis

Rajendran

et al. 2018

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. In this paper, the gimbal angle compensation method using magnetic control law has been adopted for a small satellite operating in low earth orbit under disturbance toques influence. Three light weight magnetic torquers have been used to generate the magnetic compensation torque to bring diverge gimbals at preferable angle. The magnetic control torque required to compensate the gimbal angle is based on the gimbal error rate which depends on the gimbal angle converging time. A simulation study has been performed without and with the MTGAC system to investigate the amount of generated control torque as a trade-off between the power consumption, attitude control performance and CMG dynamic performance. Numerical simulations show that the satellite with the MTGAC system generates more control torques which leads to the additional power requirement but in return results in a favorable attitude control performance and gimbal angle management. IntroductionControl moment gyroscope (CMG) is a momentum exchange device that controls satellite attitude based on the conservation of angular momentum of the satellite system [1]. It has a torque amplification characteristic which makes it as a perfect actuator for fast slew maneuver and precise attitude pointing control over other actuators such as momentum wheels and reaction wheels. These features increase the operational envelop of the satellites and subsequently increase the return of mission data and reduce payload complexity [2,3]. Control torque is generated by rotating the CMG's gimbal at certain gimbal angle rate. This causes the direction of the flywheel's angular momentum vector to change and results in a generation of control torque, orthogonal to both flywheel's spin and gimbal axes [4]. There are three types of CMG i.e. single gimbal CMG (SGCMG), double gimbal CMG (DGCMG) and variable speed CMG (VSCMG). Among these three, SGCMG is less complex and cheaper than VSCMG and it has more significant torque amplification over DGCMG [5][6][7]. However, SGCMG has drawback in term of singularity where at certain gimbal angle orientations, the control torque cannot be generated by the CMG cluster thus resulting in a loss of satellite attitude controllability. The singularity problems have lead towards the development of singularity avoidance or steering laws that can avoid or escape the CMG cluster from singular states [8][9][10][11][12].Another concern about the CMG system is the gimbal angle offset due to disturbance torques. The constant disturbance torques cause the gimbals to drift away from preferred or reference angles. This situation reduces the repeatability of slew maneuvers and can also drive the CMG cluster into saturation singularity state which most of the steering laws fail to avoid or escape. Since the CMG

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Elementary Magnetic Attitude Control System

Cited by 207 publications

References 7 publications

Optimal Control Techniques for Spacecraft Attitude Maneuvers

Optimal Control Techniques for Spacecraft Attitude Maneuvers

Rapid Initial Detumbling Strategy for Micro/Nanosatellite with Pitch Bias Momentum System

Control torque generation of a CMG-based small satellite with MTGAC system: a trade-off study

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