Design of a fault-tolerant flight control system against multiple actuator failures

Abstract

Actuator faults occurring suddenly in avionic systems can deteriorate aircraft dynamics and may lead to catastrophic instability. Since conventional flight control systems are not reliable in the presence of such risks, for many years ago and until quite recently, these faults have been handled using actuator redundancy. However, this technique leads to extra weight and costs, and thus affects the overall space, weight and power. Recent research approaches have been focused on new analytical methods, known in the literature as fault-tolerant control systems. Based on both an online fault detection and diagnosis process and a reconfigurable flight control law, these systems are capable of adapting in real time to such sudden faults while keeping avionic systems lighter and less expensive. Although the concept of reconfigurable control still remains in the experimental phase and there is no system implemented on commercial aircraft, several research programs have been created over the past 20 years to study their potential. In this thesis, fault-tolerant control systems combined the sliding mode technique and the geometric approach for fault reconstruction are developed based on Lyapunov theory of stability. The purpose is to handle multiple simultaneous actuator faults while preserving stability and maintaining desired performances. To validate the effectiveness and robustness of the proposed algorithms in faulty situations, several Matlab®/Simulink® numerical simulations are performed on high fidelity aircraft models. FlightGear software simulator is used to show the performance and the behavior of the aircraft on a graphical user interface.

Date	9 Sept 2016
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Maarouf Saad (Supervisor) & Jean-François Boland (Co-supervisor)