Linear-programming formulations of control allocation problems are considered, including those associated with direct allocation and mixed 1 -norm objectives. Primal-dual and predictor-corrector path-following interior-point algorithms, that are shown to be well suited for the control-allocation problems, are described in some detail with an emphasis on preferred implementations. The performance of each algorithm is evaluated for computational efficiency and for accuracy using linear models of a C-17 transport and a tailless fighter aircraft. Appropriate choices of stopping tolerances and other algorithm parameters are studied. Comparisons of speed and accuracy are made to the simplex method. Results show that real-time implementation of the algorithms is feasible, without requiring excessive number of computations.

Interior-Point Algorithms for Control Allocation

Eine zentrale Anforderung an unbemannte Fluggerate ist die autonome Durchfuhrung der geplanten Flugmission. Zur Erreichung dieses Zieles muss das Regelungssystem des Flugzeuges ein hohes Mas an Robustheit gegenuber Modell- und Parameterunsicherheiten sowie die Anpassungsfahigkeit aufweisen, um Stor- und Ausfallsituationen meistern zu konnen. Ferner muss die Einhaltung von Betriebsgrenzen gewahrleistet sein. Es wird ein auf nichtlinearer dynamischer Inversion beruhendes adaptives Regelungskonzept vorgestellt, das die genannten Anspruche erfullt und das den Flug auf komplexen, dreidimensionalen Bahnen mit hoher Bandbreite und groser Fuhrungsgenauigkeit ermoglicht. Das System erlaubt die volle Ausnutzung der Flugleistungen der Konfiguration und berucksichtigt insbesondere auch Sattigungen in Ruderausschlagen und -stellraten. Der Nachweis der Funktionsfahigkeit erfolgt anhand nichtlinearer Simulationen unter Verwendung eines komplexen Simulationsmodells.

https://mediatum.ub.tum.de/doc/601905/file.pdf

Nichtlineare adaptive Regelung eines unbemannten Fluggerätes

Application of Control Allocation Methods to Linear Systems with Four or More Objectives

Flying -wing configuration aircraft has multi -control -effector s redundant ly . Especially the innovative drag rudder s a re implemented on it . So the control allocation is s trongly nonlinear and multi -ax es coupl ing . The features and applicabilit y in different flight tasks of several typical control allocation methods were summarized . The multi -objective s optimiz ation method based on nonlinear programming was u tilized because of the new characteristic s of the control allocation for the flying wing configuration aircraft. The differences of control allocation results under different objectives were analyzed. And the attitude -tr acking flight control system based on nonlinear dynamic inverse theory was designed, and the d igital simulation using a six degree -of -freedom nonlinear model of certain flying -wing configuration aircraft was conducted, which demonstrate the applicability f or flying -wing configuration aircraft. The results also indicated that the impacts of different optimizing object ives on flight states were remarkable and different.

Flying -Wing Aircraft Control Allocation

Methods for allocating redundant controls for systems with four or more objectives are studied. The Bisecting Edge Search Algorithm has been presented as a computationally e‐cient method for allocating controls in the three objective problem. A recursive method for extending this algorithm to handle any number of objectives was developed. The recursive algorithm is designed to be similar to the three objective allocator and to require computational efiort which scales linearly with the controls. Numerical results illustrate how the average and worst case performance scales with the problem size. The recursive allocator is found to scale linearly with the number of controls. As the number of objectives increases, the computational time grows much faster. The estimation of solutions if the allocator is forced to exit early is discussed.

Control allocation for linear systems with four or more objectives

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii Table of

/pdf/a-comparison-of-two-methods-used-to-deal-with-saturation-of-2fkcdl1buc.pdf

Mark David Nelson

Papers

A Comparison of Two Methods Used to Deal with Saturation of Multiple, Redundant Aircraft Control Effectors