Browsing by Author "Engelbrecht, Jacobus Adriaan Albertus"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Automatic flight envelope recovery for large transport aircraft
    (Stellenbosch : Stellenbosch University, 2016-12) Engelbrecht, Jacobus Adriaan Albertus; Jones, Thomas; Peddle, Iain; Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.
    ENGLISH ABSTRACT: This thesis presents the design of an automatic flight envelope recovery system for large transport aircraft. The flight envelope of the aircraft is conceptualised to consist of the aerodynamic envelope, the attitude envelope, the flight vector envelope, and the structural integrity envelope. The time scale separation between the aircraft’s fast rigid body rotational dynamics and its slower point mass translational dynamics is exploited to separate the flight envelope recovery into an inner-loop recovery of the angular rates and aerodynamic envelope, and an outer-loop recovery of the attitude, flight path angle, and airspeed while remaining within the structural integrity envelope. Two approaches to flight envelope recovery are proposed. The first approach uses a passive method to recover the aerodynamic envelope using the natural stability of the aircraft and then uses the conventional flight control laws, with their flight envelope protection functions, to recover the aircraft attitude and flight vector. The second approach uses an active method to recover the aerodynamic envelope using a Lyapunov-based inner-loop controller and uses an outer-loop controller based on optimal control theory to recover the aircraft attitude, flight path angle and airspeed while minimising the altitude loss. The automatic flight envelope recovery is verified in simulation on the NASA Generic Transport Model (GTM), a wide-envelope aircraft model that is able to model the flight mechanics of large transport aircraft in out-of-envelope conditions.