|dc.description.abstract||This work presents the use of adaptive control methodologies for the recovery to an
aircraft carrier of an autonomous fixed wing aircraft. The control architecture used is model
reference adaptive control that is implemented in the pitch, roll, yaw, and airspeed axes to
provide 6 degree-of-freedom control of the aircraft. Control systems are developed for two
aircraft models, a Beech Bonanza representing a low speed high aspect ratio wing aircraft,
and the NAVAIR ExJet representing a high speed low aspect ratio wing aircraft.
The structure of the controller includes a first-order linear model follower, followed
by one of two methods of linear control. The first is a proportional-integral (PI) controller,
the second an adaptive critic controller. Adaptation is used to augment the command
signal produced by the linear controller, the following methods are used: adaptive bias
corrector, optimal control modification, Uadd, and local linear model compensation. An
inverse controller, which includes two methods: a force and moment buildup method and a
state space model, generates the control effector commands. The control system reference
inputs are rotational rates and airspeed, an outer-loop controller is provided to direct the
aircraft to the landing point.
Control system design is through the use of metrics based on the nominal error, time
delay margin, and landing accuracy. The control systems are then evaluated under nominal,
effector failure, and modeling error conditions.
The control systems defined are capable of providing the desired control under
nominal, failure, and error conditions; but will require refinement to improve landing