Gain-Scheduled Linear Fractional Control for Active Flutter Suppression

Abstract

A gain-scheduled controller for active flutter suppression of the NASA Langley Research Center’s Benchmark Active Controls Technology wing section is presented. The wing section changes significantly as a function of Mach and dynamic pressure and is modeled as a linear system whose parameters depend in a linear fractional manner on Mach and dynamic pressure. The resulting gain-scheduled controller also depends in a linear fractional manner on Mach and dynamic pressure. Stability of the closed-loop system over a wide range of Mach and dynamic pressure is demonstrated. Closed-loop stability is demonstrated via time simulations in which both Mach and dynamic pressure are allowed to vary in the presence of input disturbances. The linear fractional gain-scheduled controller and an optimized linear controller (designed for comparison) both achieve closed-loop stability, but the gain-scheduled controller outperforms the linear controller throughout the operating region.