Nonlinear guidance and control of leader-follower UAV formations

Kumbasar, Sarper
In this thesis work, two nonlinear guidance methods are proposed to control the autonomous formation flight: State Dependent Riccati Equation method and Lyapunov function method. Leader-Follower formation scheme is chosen and a pair of fighter aircrafts are used in simulations. One of them is chosen as the leader and it carries out the commanded maneuvers. Other aircraft is the follower and it follows the leader keeping the prescribed formation structure. Both aircraft models are nonlinear. In the inner loop, a nonlinear control algorithm, State Dependent Riccati Equation method is used to control the flight.


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In this work, the nonlinear structural modification/coupling technique proposed recently by the authors is applied to a test system in order to study the applicability of the method to real structures. The technique is based on calculating the frequency response functions of a modified system from those of the original system and the dynamic stiffness matrix of the nonlinear modifying part. The modification can also be in the form of coupling a nonlinear system to the original system. The test system used i...
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Seber, Guclu; Bendiksen, Oddvar O. (American Institute of Aeronautics and Astronautics (AIAA), 2008-06-01)
A fully nonlinear aeroelastic formulation of the direct Eulerian-Lagrangian computational scheme is presented in which both structural and aerodynamic nonlinearities are treated without approximations. The method is direct in the sense that the calculations are done at the finite element level, both in the fluid and structural domains, and the fluid-structure system is time-marched as a single dynamic system using a multistage Runge-Kutta scheme. The exact nonlinear boundary condition at the fluid-structure...
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Sensitivity analysis approach for reduced-order approximations of optimal control problems governed by Burgers equation
Akman, Tuğba (Wiley, 2016-12-01)
The reduced-order model of the optimal control problem governed by Burgers equation is derived using the proper orthogonal decomposition (POD) method. The reduced-order solution depending on parameters, which are different from the nominal values, may not be accurate if the POD basis functions depending on the nominal values are used to derive the reduced-order model. It is known that Burgers equation is sensitive to the perturbations in the diffusion term, so we use the sensitivity information to improve t...
Assessment of Transient Stability of Nonlinear Dynamic Systems by the Method of Tangent Hyperplanes and the Method of Tangent Hypersurfaces
Eskicioglu, Ahmet M. (ASME International, 1989-9-1)
Two direct methods, the method of tangent hyperplanes and the method of tangent hypersurfaces, are applied to an elementary nonlinear dynamic system for transient stability assessment. The former method is based on the approximation of the asymptotic stability boundary by hyperplanes at a certain class of unstable singular points in the state-space, and the latter replaces hyperplanes by hypersurfaces. The applicability and accuracy of both methods are evaluated through a comparison of results.
Citation Formats
S. Kumbasar, “Nonlinear guidance and control of leader-follower UAV formations,” M.S. - Master of Science, Middle East Technical University, 2015.