New method of modeling uncertainty for robust flutter suppression

A study was conducted to present a new scheme to model the state-space LFT system of a multiple-actuated wing (MAW) with airspeed and air-density uncertainties so as to reduce the dimension of the resulting uncertainty block. The mathematical model of the robust aeroservoelastic (ASE) system was established and the linear fractional transformation (LFT) model of the ASE system with airspeed uncertainty was derived by using Moulin's method and new scheme. The LFT model of the ASE system with airspeed and air-density variations was also presented. Two kinds of μ controllers, such as a single-input/single-output (SISO) controller and a multi-input/multi-output (MIMO) controller, were presented to suppress the flutter instability of the MAW model incorporating airspeed and air-density variations.