Effect of Kinematic Rotation-Translation Coupling on Relative Spacecraft Translational Dynamics

摘要

In this paper, a kinematically coupled relative rotational and translational motion model, describing the 6 degrees-of-freedom relative dynamics between two rigid-body spacecraft was developed. The newly developed model generalizes the existing nonlinear relative-translation model to include trajectories of points that are not located on the spacecraft centers of mass. The relative motion of the non-cm, points was illustrated by using two numerical simulations: a formation flying scenario and a rendezvous mission. The main observation is that neglecting the relative translation induced by the relative rotation can lead to considerable errors in distributed space systems flying in close proximity.rnIt was demonstrated that the points that are not located on the spacecraft cm. are oscillating harmonically with respect to the leader spacecraft's cm. This motion cannot be detected using traditional relative motion models. It was also shown that using the linear Clohessy-Wiltshire model can lead to considerable errors when applied to modeling of rendezvous and docking.rnOrbital perturbations may induce differential dynamics that is more significant than the kinematic coupling effect. However, the latter effect is always present, even in short operation times (typical, for example, to orbital rendezvous), where orbital perturbations are less dominant. In fact, the kinematic coupling effect does not depend on environmental perturbations and is an inherent part of the nominal relative motion equations. As such, it should be taken into account in the linearized relative-translation equations.