Introduction to Quantitative Feedback Theory for lateral robust flight control systems design

Quantitative Feedback Theory (QFT), is a frequency-domain-based robust cont rol design approach that was developed in the early 1970s and has received considerable attention over the past two decades. In the last few years, it s application to aircraft flight control systems design has been widely inv estigated. In this paper the basic concepts, principles. design procedure, and Features of QFT are reviewed and summarized for single-input single-out put systems. Its application to a lateral flight control system design is t hen considered. A robust roll-attitude control system is designed to cover a certain operating range using the QFT methodology, and certain eigenstruc ture-assignment results. The integration of QFT with eigenstructure methods results in a controller with the stability and performance robustness of Q FT design, and the decoupled dynamic responses of an eigenstructure-assignm ent approach. The results indicate QFT has significant potential in robust flight control systems design. The combination of techniques should be appl icable to other industrial sectors. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.