Experimental Testing of a CMG Cluster for Agile Microsatellites

V. J. Lappas; W. H. Steyn; C. I. Underwood (2004), JBIS, 57, 318-324

Refcode: 2004.57.318
Keywords: Attitude control, control moment gyros, microsatellites, reaction wheels, agility

Abstract:
This paper presents experimental results on the performance of a Control Moment Gyroscope (CMG) cluster. The goal is to design a CMG cluster for 3-axis control for agile microsatellites. The experimental data are compared with simulation (theoretical) results and both are used to verify the principles, benefits and performance specifications of the CMG cluster. The main aims are:

1. To practically confirm the theoretical work (simulations) performed in previous CMG studies

2. To validate the viability of using CMG�s as actuators on a microsatellite in a practical way

3. To confirm the agility and power efficiency that CMGs can potentially provide to microsatellites

CMG systems are considered to be in the literature more efficient devices from an electrical power point of view, than current actuators such as reaction/momentum wheels (RW/MW). Thus it becomes important to measure the electrical power consumption of a CMG system. These measurements are presented in this paper and then compared to two of SSTL’s RWs. These RWs are currently operational and in orbit: SSTL’s minisatellite UoSAT-12 RW and Tsinghua University’s Tsinghua-1 microsatellite RW. CMGs are shown to have a potential performance advantage over RW/MW, for spacecraft with agile requirements.