Aeroservoelastic stability analysis in frequency domain using structured singular value

Based on the robust aeroelastic theory and and the frequency domain unsteady aerodynamics, complex perturbation of dynamic pressure was introduced in a frequency domain aeroservoelastic system to formulate the corresponding μ-analysis framework. Under this framework, the structured singular value theory was applied to predict the critical stability point of the aeroservoelastic system. It was shown that with complex perturbation, this frequency domain method not only guarantees the continuity of structured singular value of the system, but also leads to a more accurate numerical result. Numerical study was 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 with the proposed method agreed well with that obtained with the conventional p-k method.