Title: LMI-based control law for variable-speed control moment gyros in flexible spacecraft

Authors: Shinya Kasai; Hirohisa Kojima

Addresses: Department of Aerospace Engineering, Graduate School of System Design, Tokyo Metropolitan University, 6-6 Asahigaoka, Hino, Tokyo 191-0065, Japan ' Department of Aerospace Engineering, Graduate School of System Design, Tokyo Metropolitan University, 6-6 Asahigaoka, Hino, Tokyo 191-0065, Japan

Abstract: A linear matrix inequality (LMI)-based control law for variable-speed control moment gyros (VSCMGs) for flexible spacecraft is proposed in this study. This proposed control law is designed by H∞ synthesis via LMI, considering the characteristics of the VSCMG system, the reaction wheel (RW), and vibration suppression. However, this proposed control law should be applied near the end of a manoeuvre because the control moment gyro (CMG) system is nonlinear and the proposed controller is a linear controller based on H∞ synthesis. In this study, to smoothly transition between the CMG and RW modes, the steering control law is designed as a gain-scheduled steering control law for the VSCMGs, which consists of the generalised singularity-robust term and the local gradient-based (LG) null motion term for the VSCMGs before the end of the manoeuvre. The numerical results show that the proposed steering law can effectively stabilise the attitude and suppress vibration.

Keywords: variable-speed CMGs; control moment gyros; VSCMGs; H-infinity control; linear matrix inequalities; LMIs; steering control law; flexible spacecraft; reaction wheel; vibration suppression; attitude stability.

DOI: 10.1504/IJSPACESE.2015.073215

International Journal of Space Science and Engineering, 2015 Vol.3 No.3, pp.246 - 278

Received: 22 Sep 2015
Accepted: 23 Sep 2015

Published online: 27 Nov 2015 *

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