H-infinity controller design for attitude control of a satellite with flexible appendages

Abstract

The attitude control of a satellite with flexible appendages such as solar arrays and antennas is represented in this research. Flexible appendages of the satellite have large area and thin thickness, so they vibrate as the satellite maneuvers. If the vibration modes are not controlled, they lead to degradation of satellite attitude stability and pointing accuracy. Therefore, the H-infinity control method, which is one of the robust control methods was introduced. At first, linear dynamic equations for the satellite with flexible appendages were derived from the rigid-flexible satellite model and finite element method. Then, the H-infinity controller was designed based on the mixed-sensitivity design with weighting function selection process. Finally, time response and frequency response of the resultant controller were analyzed in terms of robustness and performance. The simulation results were represented with model uncertainties and time delay to check whether the controller can be applied to satellite with flexible appendages.