Date of Award


Document Type


Degree Name

Master of Science


Department of Aeronautics and Astronautics

First Advisor

Bradley S. Liebst, PhD


This thesis addresses the application issues raised implementing flight control designs derived from optimal control theory and the challenges in obtaining acceptable handling qualities when using these techniques. Using the USAF TPS FCS project as the controller architecture, four controllers were designed using classical methods, and H2, H3, and mixed H2/H optimal control theory. These designs were implemented in the Calspan VSS II Learjet, simulating unstable aircraft longitudinal dynamics and a limited handling qualities flight test evaluation was performed. The design phase found the optimal control techniques, as applied, difficult to design to handling qualities specifications. The H2, H3 and mixed H2/H controllers were unstable and often contained high frequency poles, which were difficult to implement. The flight test rated the designs acceptable on approach, but no handling qualities level for approach was determined.

AFIT Designator


DTIC Accession Number