Tracking control using attitude measurements for flexible spacecraft in presence of disturbances

The problem of tracking a desired attitude is here addressed in the case of a flexible spacecraft subject to environmental disturbances. This problem is solved in a practical way for attitude maneuvers with bounded velocity and acceleration and for disturbances with bounded dynamics, ensuring the ultimate boundedness of the system trajectories. The variables available for feedback are those describing the spacecraft attitude. The unmeasured variables, such as the angular velocity and the modal position and velocity, along with the disturbance acting on the spacecraft, are reconstructed by means of appropriate dynamics.