Adaptive nonlinear control for spacecraft formation flying with coupled translational and attitude dynamics

In this paper, we address a tracking control problem for the coupled translational and attitude motion of a follower spacecraft relative to a leader spacecraft. Using the vectrix formalism the translational and attitude dynamics of the leader and follower spacecraft are modeled, where the mutual coupling, in each spacecraft's translational and attitude motion induced by their gravitational interaction is duly accounted. Using a Lyapunov framework, nonlinear control and adaptation laws are designed that ensure the global asymptotic convergence of the relative translational and attitude position tracking errors, despite the presence of unknown mass and inertia parameters of tile leader and follower spacecraft.