Agile and robust attitude control system for VSOP-2 satellite “ASTRO-G”

ASTRO-G will be launched for VSOP (VLBI Space Observatory Program)-2. In the ASTRO-G mission, attitude control system is required to have both robustness to modeling error and high performance of response. In the current strategy, feedforward control is mainly applied to ASTRO-G control system. Feedback control is, however, desirable because it can have robustness against unexpected disturbance. In this paper, we studied whether feedback control is applicable for ASTRO-G control system. First, 2DOF (degree-of-freedom) control with H_alpha controller and reference called "NME (nil-mode-exciting) profiler" was applied to ASTRO-G attitude control system. Then, reference which was made by convolving NME profiler and Input shaping was proposed. The simulation results show both the effectiveness of 2 DOF control system with proposed reference, and applicability of feedback control.