Robust tracking controller for a seeker scan loop

This paper deals with the problem of designing a robust tracking controller for a seeker scan loop, where the plant model contains uncertainty. The goal is to have the seeker accurately track specific scan patterns in the presence of system uncertainty. Two scan patterns, the circular and the rosette, are generated as reference models and used in the simulation to test the robustness of the controllers. Results from H-infinity control theory for full state feedback and output feedback are used to design the controllers, Furthermore, to limit the control force magnitude to satisfy physical constraints, a special filtering procedure is introduced. For both scan patterns, it is shown that robust controllers can be determined so that the scan loop accurately tracks the scan patterns even with model uncertainty up to 100%.