Browsing by Author "Jan, YW"

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Attitude control system for ROCSAT-3 microsatellite: a conceptual design
(2005-02-01)
Jan, YW
;
Chiou, JC
;
電控工程研究所
;
Institute of Electrical and Control Engineering
The ROCSAT-3 attitude control subsystem is conceptually designed to meet the weight and power constraints of a microsatellite. Attractive features of the proposed design include (a) a control scheme for initial attitude acquisition, which provides a fully autonomous attitude hold, no duration limit and adequate attitude for power generation and (b) a feasible implementation for a microsatellite which has uncommon mission demands such as an orbit raising maneuver and practical weight and power constraints. The proposed control schemes for the three control modes and the spacecraft attitude dynamics are analyzed to demonstrate the satisfaction of the designated mission goals. (C) 2004 Elsevier Ltd. All rights reserved.
Minimum-time spacecraft maneuver using sliding-mode control
(2004-01-01)
Jan, YW
;
Chiou, JC
;
電控工程研究所
;
Institute of Electrical and Control Engineering
The purpose of this paper is to present a sliding mode control method that can be used to perform a spacecraft large angle maneuver with minimum time. An algorithm of minimum-time SMC is developed to provide the robust tracking control. The simulation results are compared with previous developed control schemes, eigenaxis quaternion regulator, to demonstrate the superiority of the proposed sliding mode control algorithm. (C) 2003 Elsevier Ltd. All rights reserved.
Unloading law for a LEO spacecraft with two-gimbals solar array
(2002-12-01)
Jan, YW
;
Chiou, JC
;
電控工程研究所
;
Institute of Electrical and Control Engineering
The purpose of this paper is to present a modified cross-product unloading law that can be used to provide an open-loop compensation control design to counteract the predominant effects of the gravity gradient torque. The modified cross-product unloading law, is successfully applied to a three-axis stabilized, nadir-pointed LEO spacecraft with two-gimbals solar array. The variation of the two solar array orientations can significantly change the spacecraft's moment of inertia during the nominal operation mode, which can produce significant momentum accumulation in the roll-yaw body plane and cause large yaw pointing error. A rigorous study of momentum management performance capability has been conducted by using a high-fidelity performance simulation software that contains models of four environmental disturbance torque (gravity gradient, aerodynamic, solar, and magnetic). The simulation results show that the proposed momentum unloading control law has enabled a substantial reduction in the maximum accumulated roll momentum, which results in improving the pointing accuracy of the LEO spacecraft enormously. (C) 2002 Published by Elsevier Science Ltd.