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Paper: Attitude Control System Design for Fast Rest-to-Rest Attitude Maneuver
Volume: 402, Approaching Micro-Arcsecond Resolution with VSOP-2: Astrophysics and Technologies
Page: 56
Authors: Sakai, S.; Bando, N.; Hashimoto, T.; Murata, Y.; Mochizuki, N.; Nakamura, T.; Kamiya, T.; Ogura, N.; Maeda, K.
Abstract: The VSOP-2 project is a new space VLBI (very long baseline interferometer) radio astronomy mission, proposed to inherit the fruitful success of the VSOP mission with the HALCA satellite. One of the most important advances of VSOP-2 is the use of higher observation frequency, which requires fast alternating observation of a target and calibrator in order to remove the phase changes caused by the atmosphere. Typically, both sources must be observed within 60 sec, and this switching must be carried out over many hours. “ASTRO-G” is a satellite planned for this VSOP-2 project, and one of technical challenges is to achieve such fast rest-to-rest maneuvers, and the proper hardware must be selected to account for this fast attitude maneuver. The controlled momentum gyro (CMG) is an actuator that provides high torque with small power consumption, and the fiber optical gyro is a sensor able to measure the high angular velocity with excellent accuracy. This paper first describes these components for attitude control. Another challenge of the ASTRO-G’s attitude control system is to design the switching for the flexible mode of the satellite structure, containing a large deployable reflector and a large solar panel. These produce resonances with fast switching and these must be attenuated. To achieve high agility in a flexible satellite, the controller design is crucial. One design feature is a novel robust input shaper named “nil mode exciting profiler”. Another feature is the feedback controller design. The paper describes these features and other potential problems with fast switching.
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