How do you analyze aeroservoelastic interactions in flight control systems?

Aeroservoelasticity (ASE) couples flexible aircraft structure, unsteady aerodynamics, and flight control system. Analysis approach: Develop reduced-order structural model (modal representation), Couple with unsteady aerodynamics (DLM, CFD-based ROM), Include control system dynamics (actuators, sensors, filters, control laws), Form closed-loop aeroservoelastic model, and Evaluate stability (Nichols plots, notch filter placement). Concerns: Structural modes excited by control system, Sensor placement in high-gain modal regions, and Actuator bandwidth interaction with structural frequencies. Notch filters attenuate specific frequencies but add phase lag. Modern approaches use structured singular value (mu) analysis for robustness. Flight test validates analytical margins through structural mode excitation. Critical for large flexible aircraft (787, A350) and high-performance fighters.