Adaptive attitude stability and control for Space Station/Orbiter berthing operations

The fully coupled, systematically linearized equations of motion are used for attitude control system design of an early Space Station Freedom flight configuration. These equations are valid around any estimated spacecraft equilibrium point. A full state feedback controller, incorporating gain scheduled adaptation of the attitude gains, is developed for use during spacecraft on-orbit operations characterized by significant mass properties variations. Feasibility of the gain adaptation is demonstrated via a Space Station Freedom/Orbiter berthing operation scenario. The attitude controller transient performance during gain adaptation appear satisfactory.