Control system design for morphing aircraft
The focus of this study is flight control design of morphing aircraft. In recent years, advances in smart technologies and lightweight materials have fueled interest in morphing airvehicles. Typically, lightweight materials are used in airframe design as a means to reduce aircraft weight without compromising their strength and durability. This leads to an increase in structural flexibility, which in turn leads to an increase in effects of aeroelastic interactions. These effects can result in significant issues with aircraft stability and control. Subsequently, there has been much interest in control law design for morphing aircraft. In this dissertation, five control designs for three morphing aircraft are developed for the longitudinal aircraft dynamics. First an adaptive critic neural network based controller, called Single Network Adaptive Critic (SNAC), and is used on a single engine, light airplane similar to the Cessna 182 Skylane, which is assumed to be able to perform a rapid change in wing sweep. Following this design, a SNAC architecture is used for optimal control of a morphing fighter aircraft McDonnell Douglass F-4 Phantom during a pull-up maneuver, and the performance of the aircraft is investigated from a flight dynamics perspective during this maneuver, performed at the same time as a rapid wing sweep. The third morphing baseline aircraft is an elastically shaped aircraft concept (ESAC) with highly flexible wings and variable camber capability, and multiple distributed flaps and slats as control surfaces. For this aircraft, three design approaches are explored. The first one is a state feedback optimal control, and then a static output feedback optimal control design incorporating a multi-objective performance index that includes an explicit drag minimization term. Lastly a decentralized controller, that uses the elevator for rigid body control and the distributed flaps and slats for the flexible control effects, is designed.