Distributed attitude synchronization control for a group of flexible spacecraft using only attitude measurements

This paper considers the problem of attitude synchronization control of a group of flexible spacecraft under an undirected communication graph and in the absence of measurements of both modal variables and spacecraft angular velocities. To solve this problem, a nonlinear observer is introduced to estimate the unmeasurable modal variables and spacecraft angular velocities. Then, the backstepping technique is used to design the control law. The stability of the overall closed-loop system is guaranteed by the Lyapunov approach together with Barbalat’s Lemma. The performance of the control scheme derived here is illustrated through numerical simulations.