Distributed leader-following velocity-free coordinated attitude tracking control for multiple spacecraft

In this paper, we investigate the distributed leader-following velocity-free coordinated attitude tracking control problem for multiple spacecraft under a communication graph containing a spanning tree with the virtual leader as the root. Most results on this problem rely on the assumption that the attitude and angular velocity of the leader are available to every follower. Aiming at solving the problem, a distributed finite-time attitude and angular velocity observer is developed to estimate the state of the leader. Furthermore, removing the structure constraint of the leader's angular velocity, a new distributed finite-time observer is designed to obtain the estimation of the angular acceleration of the leader. Meanwhile, by introducing an auxiliary compensation system, the angular velocity of the followers is not required. Based on the distributed finite-time state observer, the finite-time angular acceleration observer and the auxiliary compensation system, a distributed leader-following velocity-free attitude coordination control algorithm for multiple spacecraft is designed to regulate the following spacecraft to track a common time-varying reference trajectory simultaneously. Numerical simulation is provided to verify the proposed control scheme.