Direct Model Reference Adaptive Attitude Control of a PNP Satellite with Unknown Dynamics

A great amount of research has been done in the area of adaptive estimation and control of spacecraft. A large portion of the research uses indirect adaptive control, to estimate parameters of the plant that are either unknown or contain perturbations. The Responsive Space Initiative is currently working on Plug-and-Play [PNP] satellites. Due to the very nature of these satellites, their dynamic models will have signiflcant model perturbations in several areas. These areas include but are not limited to, reaction wheel mounting/orientation, star tracker location/orientation, satellite center of mass (COM),and payload location/orientation. It is not practical to try and develop individual indirect adaptive controllers to estimate and correct each perturbation. A Direct Model Reference Adaptive Controller will be developed and demonstrated to accurately/robustly control the nonlinear dynamic model of a PNP satellite despite very limited plant knowledge.