Control of flexible aircraft executing time-dependent maneuvers

A new generation of aircraft, namely, unmanned aerial vehicles (UAVs), and, in particular, autonomous UAVs, are expected to carry out very critical maneuvers, well in excess of what pilots are able to tolerate. A newly developed theory for the dynamics and control of maneuvering flexible aircraft is ideally suited for the analysis and design of such aircraft. The state equations for maneuvering flexible aircraft are nonlinear and of high dimension. With due consideration to the way aircraft are flown, the problem can be separated into one for the generally large aircraft motions on a given flight path and another one for small perturbations from the flight path and elastic vibration, where the second problem receives inputs from the first. The case in which the flight path represents a time-dependent maneuver, so that the system of perturbation equations is time varying is studied. Several developments designed to facilitate the treatment of time-varying systems are provided. In particular, included are 1) an explicit derivation of the matrices defining the state equations, 2) a new approach to the control of the perturbations from the flight path and the elastic vibration, and 3) expressions for the implementation of the controls in discrete time. Computer solutions for the system response can be carried out conveniently by the use of MATLAB® and MATHEMATICA. A numerical example illustrates the approach for the case of a flexible aircraft executing a pitch maneuver.