Abstract: This article deals with torque allocation for redundant flywheel configurations in a spacecraft attitude control system. First of all, an energy-based optimal allocation strategy is introduced after some fundamental description of this issue, and a saturation logic is devised subject to the physical constraints of flywheel torque. Then for a four-flywheel and a multi-flywheel system, two torque-based optimal allocation logics are developed respectively based on static optimization theory and attributes of flywheels. Since both allocation strategies can drive the corresponding flywheel system to reach their maximal torque capacity, they are both of significant value in engineering applications. Finally, torque envelopes for some general flywheel configurations using the energy-based and toque-based optimal allocation strategies are analyzed and compared to show the effectiveness of the proposed methods.

Key words: redundant system, flywheels, attitude control, torque allocation, energy optimal, torque optimal