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Typical design challenges for Unmanned Aerial Vehicles (UAVs) require low aerodynamic drag and structural weight. Both of these requirements imply that these aircraft are considerably more flexible than conventional aircraft and their stability analyses are more complex since they require models unifying rigid body and elastic dynamics. This paper aims to built such a model for a generic UAV. The model is then used to address stability in terms of divergence and flutter.

An outer loop guidance architecture was designed to control autonomous aerial refueling mission from the trail aircraft side. The design utilized bank, yaw rate, velocity and climb rate commands implemented using a previously developed adaptive trajectory concept. The concept was based on position error feedback that was used to control trail aircraft overshoot and tracking about the lead aircraft refueling point. To demonstrate this application, an open loop linear trail aircraft model at a given flight condition was selected. Inner loop control laws were designed using Linear Quadratic Regulator feedback controller and Balanced Deviation theory. The outer loop guidance architecture was then added to implement the application. The performance of the system was then evaluated for a selected position error, and disturbance.

The objective of this paper is to address stability of Unmanned Aerial Vehicles (UAVs). The paper first derives the equations of motion for a generic UAV that account for both rigid-body and elastic degrees of freedom in coupled form, as well as nonlinear structural and unsteady aerodynamic effects. The equations are used to compute trim states for steady level flight at desired altitudes and speeds. Aircraft stability is addressed by linearizing the equations about the desired steady level flight, and solving the corresponding eigenvalue problem. The paper shows that other aircraft models widely used for addressing stability can be obtained from the “full model” as special cases.

This paper aims to derive a comprehensive dynamical model and analysis of a High-Altitude-Long-Endurance (HALE) Unmanned Aerial Vehicles (UAVs). Structure of such an aircraft needs to be lightweight and capable of carrying a substantial payload. For low drag, the aircraft must have high aspect ratio. Moreover, safety factors for these aircraft are not as high as those for manned aircraft. These imply that HALE UAVs are considerably more flexible than manned aircraft. Hence, in the dynamical analysis of such aircraft, a formulation unifying the elastic and rigid body motions of the aircraft must be used. A newly developed theory for the dynamics of maneuvering flexible aircraft is ideally suited for the analysis of such aircraft. The uniqueness of this paper lies in its nonlinear structural model. The equations of motion are obtained by means of the Lagrangian equations in quasicoordinates. A perturbation approach separates the problem into nominal dynamics and perturbation dynamics.

This paper concerns with control of Unmanned Aerial Vehicles (UAVs), which are expected to carry out very critical maneuvers, well in excess of what pilots are able to tolerate. Safety factors for these aircraft are not as high as those for manned aircraft and they are lighter than the manned aircraft. These imply that UAVs are considerably more flexible than the manned aircraft. 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 control input can be conceived as having two parts, one part designed to steer the aircraft to permit the realization of a desired flight trajectory and another part designed to reduce any deviations from the desired trajectory. Control design for steering the aircraft can be achieved by using the inverse dynamics of quasi-rigid aircraft (aircraft treated as rigid). On the other hand, control design for the deviations requires output feedback control.