21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-1.10.4

FUZZY STABILITY AUGMENTATION SYSTEM FOR AIRCRAFT HANDLING QUALITIES

Bousson K., Paglione P.
University of Beira Interior, Portugal

Keywords: fuzzy stability augmentation, aircraft handling qualities

The handling qualities of an aircraft are those qualities or features that govern the ease and precision with which a human pilot is able to perform actions. Therefore, the requirements akin to them are subjective, hence they can only be described qualitatively. Stability augmentation systems are means for suitably providing the aircraft with appropriate handling qualities. They are based on state feedback control concepts and improve the stability characteristics of aircraft which lack desirable handling qualities. However, most of the existing stability augmentation systems only cope with real-valued feedback gains. Since the flight characteristics vary smoothly in the flight envelope and that unknown disturbances may affect the aircraft dynamics, existing stability augmentation systems usually produce not so reliable control performance. The present paper proposes a method for stability augmentation in which the requirements for the handling qualities are modeled by using fuzzy sets to capture the subjective features tied to the concept of quality.

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