A Hierarchical Fuzzy Logic Controller with a Velocity Modifier for Restructurable Flight Control Systems


One of the most difficult tasks faced by a restructurable flight control system is successfully performing the identification, isolation, and parameter estimation of faults. In response to this problem, an alternative, fuzzy logic based approach which avoids isolation and parameter estimation is proposed in this study. A flight control system consisting of four two-input-one-output fuzzy logic controllers controls the longitudinal, lateral, and directional modes, as well as velocity of the aircraft with a common knowledge base shared by all four modes is presented. The fuzzy control employs a hierarchical structure for finer trim corrections. The proposed fuzzy logic controller handles nominal as well as faulty conditions under the same set of rules without any modification. The simulation results show that the proposed design, in conjunction with a fuzzy logic trim velocity modifier can stabilize a damaged aircraft at the given flight conditions. The damaged aircraft is restored to a different set of equilibrium conditions when the original flight condition is unsustainable.


Mechanical and Aerospace Engineering

Document Type

Article - Conference proceedings

Document Version


File Type





© 2024 The Authors, All rights reserved.

Publication Date

01 Jan 1995

This document is currently not available here.