Distributed adaptive fault-tolerant attitude tracking of multiple flexible spacecraft on SO(3)

This paper presents distributed adaptive fault-tolerant control for the attitude tracking of multiple flexible spacecraft on SO(3) without modal variable measurement. Assume that the communication graph among the followers is undirected and connected and there exists at least one follower linked to the leader. To deal with the distributed tracking on SO(3), a finite-time observer is designed to estimate the leader's information for the followers. A distributed adaptive fault-tolerant controller is proposed to achieve the attitude tracking based on the estimation of the unmeasurable modal variables. The separation principle between the finite-time observer and the proposed controller is adopted to prove the controller convergence. Since the controllers are developed on SO(3) directly, the singularity and ambiguity associated with other attitude representations can be avoided. Finally, numerical simulations are conducted to demonstrate the effectiveness of the proposed control protocols.