The Attitude Control Problem for Flexible Satellites 650584
An attitude control system for a flexible satellite is investigated. It is assumed that the satellite can be analyzed, at least to a first approximation, as a thin circular plate. Certain types of orbiting telescopes fall in this category. The modes of vibration of this system are determined and their influence on the performance quality of a three axis control system is studied. Essential complications in the analysis stem from the non-linear gyroscopic coupling terms as well as the coupling of rigid body and elastic motion.
It is shown that the elastic motions are reflected on only one axis of the vehicle with proper location of sensors, and that the control system can be made insensitive to the two lowest vibration modes. Furthermore, the inter axis coupling has negligible influence on the system stability if the control system for each axis is properly designed.