Flight envelope expansion in landing phase using classic, intelligent, and adaptive controllers

An expanding flight envelope in the landing phase of a typical jet transport aircraft in presence of strong wind shears using a learning capable control system (LCCS) is investigated. The idea stems from human beings functional architecture that gives them the ability to do more as they age and gain more experience. With the knowledge that classical controllers lack sufficient generality to cope with nonlinear as well as uncertain phenomenon such as turbulent air, the focuse is on different types of intelligent controllers due to their learning and nonlinear generalization capabilities as candidates for the landing flight phase. It is shown that the latter class of controllers could be used to enable the aircraft to learn and gain experience as they land more and more in gusty conditions. This capability enables the aircraft to land in conditions slightly more severe than previous experiences, and hence, as far as the landing phase is concerned, the flight envelop is expanded as the aircraft ages. In this regard, five controllers including a classical proportional-integral-derivative (PID) plus three intelligent controllers, in addition to an adaptive one, are presented and compared, based on neural networks and fuzzy logic concepts. The robustness and performance of the controllers are evaluated by applying two different strong wind patterns for two levels of performance.