Attitude control reconfigurability analysis of 4-CMGs pyramid configuration spacecraft

In this paper, attitude control reconfigurability of a four pyramid-type actuators spacecraft is analyzed in different actuator faults cases based on the controllability theory. The results of controllability and small-time local controllability (STLC) of the faulty system are proven by Lie algebra and convex theory. A time index is introduced based on the optimal control theory to evaluate the speed of reconfiguration in gimbal faults cases. The condition that guarantees the reconfigurability of the system is obtained with the controllability of the faulty system, which implies that the system is always reconfigurable when there is at least one actuator working even with partial failure. Moreover, our results indicate that the failures of rotors influence the STLC of the system while the failures of gimbals degrade the speed of attitude adjustment.