Adaptive Leader-following Consensus of Multiple Uncertain Rigid Spacecraft Systems ⋆

In this paper, we consider the leader-following consensus problem for multiple uncertain rigid spacecraft systems with the attitude being represented by unit quaternion. Existing results on this problem rely on the assumption that all parameters of the rigid spacecraft system are known exactly. By employing a nonlinear distributed observer for the leader system, we first convert the leader-following consensus problem into a global adaptive stabilization problem of a well defined error system. Then, under the standard assumption that the state of the leader can reach every follower through a path, we further show that this stabilization problem is solvable by a distributed adaptive control law.