Multicriteria analysis of an L₁ adaptive flight control system

This article presents an overview of the application of the Parameter Space Investigation method for the multicriteria design optimization of the L ₁ adaptive flight control system implemented on the two turbine-powered dynamically-scaled generic transport model Airborne Subscale Transport Aircraft Research aircraft. In particular, this study addresses the improvement of a nominal prototype solution, obtained using basic design guidelines of L₁ adaptive control theory. The results validate the theoretical claims of L₁ adaptive control in terms of closed-loop performance and robustness and illustrate the systematic character of its design procedure. Furthermore, this article shows the suitability of the Parameter Space Investigation method for the multicriteria design optimization over a multidimensional design variable space of a flight control system subject to desired control specifications. The use of this particular method is of special interest, as it provides invaluable information about the behavior of the closed-loop system in an extended space of design parameters and performance criteria. The results and conclusions of this article have led to a deeper understanding of the characteristics of the closed-loop adaptive system and have contributed to the improvement of the flying qualities and the robustness margins of the adaptive L₁-augmented aircraft, which has been recently flight tested by National Aeronautics and Space Administration.