Application of a six degrees of freedom adaptive controller to a general aviation aircraft
In an effort to increase general aviation safety, a simplified model reference adaptive control (MRAC), adapting to modeling error with only a bias neuron, is applied to a desktop simulation of the Hawker Beechcraft Corporation (HBC) CJ-144 fly-by-wire aircraft in six degrees of freedom. MRAC has been experimentally applied to military and commercial aircraft by the National Aeronautics and Space Administration and the Department of Defense. Previous research at Wichita State University has demonstrated promising results for MRAC’s application to general aviation in three degrees of freedom, both in its ability to achieve desired handling qualities and adapt to unexpected changes in aircraft dynamics. MRAC is used to control the aircraft in the nominal case and adapts to maintain control with changes in flight condition or unexpected A matrix and B matrix failures. The HBC CJ-144 aircraft is configured for decoupled flight control where the pilot commands the airspeed, flight path angle, bank angle, and side force. The controller architecture consists of an inverse controller, single bias neuron adaptive element, model follower and linear controller. A six degrees of freedom dynamic inverse controller is derived to calculate the necessary thrust and control surface deflections in the nominal flight case. An artificial neural network is trained online to correct for uncertainties in the inverse and to adapt to changes in either the flight condition or the aircraft itself. The aircraft response is shaped by a model follower and linear controller. An artificial time delay metric is used to tune the controller gains for the desired performance. The controller and aircraft are simulated in the MATLAB/Simulink environment. Time response results are presented for maneuvers in each axis as well as aircraft response to unexpected failures. In simulation, the desired aircraft response was achieved. Additionally, the controller was able to maintain stability and complete maneuvers following A and B matrix failures. This controller is designed to be flight tested on the HBC CJ-144 fly-by-wire testbed.
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Aerospace Engineering.