Abstract:Based on the robust aeroelastic theory and frequency domain unsteady aerodynamics, complex perturbation of dynamic pressure is introduced in frequency domain aeroservoelastic system to formulate the corresponding mu-analysis framework. Under this framework, structured singular value theory is applied to predict the critical stability point of the aeroservoelastic system. With complex perturbation, this frequency domain method not only guarantees the continuity of structured singular value, but also leads to a rather accurate numerical result. Numerical study is performed for an aircraft augmented with multiple-input and multiple-output (MIMO) flight control system in yaw and roll motions. The critical stability point predicted by the present method agrees well with that obtained by the conventional p-k method.