Real-time identification of aircraft physical models for fault tolerant flight control

Abstract

The primary goal of aircraft fault tolerant flight control is to recover or maintain safe flight when failures have occurred. Aircraft failures can be categorized into subsystem failures and airframe/structural failures. Modern aircraft subsystems are equipped with redundancies and failure detection systems for maintaining and monitoring the health status of subsystems. However, when failures such as engine separations, vertical tail loss, or wing separation (see Chapter 1) have occurred to aircraft, the airframe/structure of the aircraft will experience significant changes. These failures are not detected by current on-board monitoring systems. As a consequence of these failures, the aerodynamicmodel and even themass/inertia properties of the aircraft will be obviously different from their nominal forms. The basic flight control system designed for the nominal aircraft will suffer from the new configuration of the vehicle. In most cases, the human pilot will take over from the automatic flight control system (autopilot) when unexpected behaviour has been recognised, and will try to handle the aircraft manually. Experienced pilots have been trained for handling aircraft with a limited number of failures. However, unsuccessful recovery of the flight may still happen due to human errors or limitations imposed by the flight control architecture. Many cases referring to human errors causing incidents/accidents have been reported. In those cases, situational awareness and psychological stress have been the major factors of introducing wrong decisions/commands from human pilots (see Chapter 1). © 2010 Springer-Verlag Berlin Heidelberg.