Accommodation of Failures in the Flight Control System of the F-16 Aircraft using Adaptive Control

Unpredictable changes in the dynamics of an aircraft due to battle damage or hardware failure may easily destroy the stability properties of most flight control systems. In this paper we examine the effect of surface and hardware failure on the flight control system of the F-16 fighter aircraft developed in [1]. In the absence of failures and unpredictable changes, the controller of [1] which is based on gain scheduling performs very well and exhibits a good degree of robustness even for high angles of attack However, in the presence of failures its performance deteriorates severly. In order to accommodate possible failures and therefore maintain the good performance characteristics of the aircraft, the control system [1] is augmented with a hybrid adaptive linear quadratic control scheme. The augmented adaptive flight control system has now the capability of learning and accommodating on line any drastic changes in the aircraft dynamics due to surface or hardware failure. The proposed flight control system is tested on the nonlinear model of the F-16 aircraft given in [1] and the simulation results demonstrate its ability to accommodate control failures and maintain good performance.