Tracking Reference Orbits Around Asteroids with Unknown Gravitational Parameters Using a Nonlinear Adaptive Controller

摘要

In this paper, a nonlinear adaptive controller is implemented to track reference orbit trajectories around asteroids or small bodies. The two-body problem with a rotating reference frame is used to model the dynamics of the spacecraft with respect to the asteroid frame of reference. Gravitational perturbations, solar radiation pressure and other unmodeled dynamics are taken as disturbances to the system model. This type of controller has several advantages over other conventional controllers in the presence of uncertain system properties. Preliminary results shows accurate tracking of desired trajectories around asteroid Ida in the presence of unknown gravitational perturbations.