H-INFINITY CONTROL OF AN EARTH OBSERVATION SATELLITE

Results of a research program to design a high-performance attitude co ntrol system for an Earth observation satellite are presented. The con troller is designed using the H-infinity coprime factorization approac h. Two steps are necessary to perform the synthesis: a classical loop shaping and an H-infinity robust stabilization. A continuous time cont roller is first designed. Robustness against parameter uncertainties i s then checked using mixed real/complex CL analysis. Last, a discrete time synthesis is performed to provide the controller to implement. Ti le same loop shape is used in continuous time as in discrete time, Res ults concerning the implementation of the controller in a nonlinear si mulation are detailed.