Robust Turbulence Load Alleviation

Using a comparatively detailed aeroelastic model for a generic commuter aircraft, a turbulence load alleviation system is designed with the objective of reducing structural fatigue. An H∞-optimal controller for the nominal model is found to be highly sensitive to small disturbances in the control system dynamics, so that a slightly perturbed closed-loop model is destabilized. Robust control methods are exploited to construct an alternative controller which improves robustness to disturbances at a small cost in nominal performance. Finally, fatigue loads experienced by the (open-loop and controlled) model are evaluated by means of two different load reconstruction methods, showing that the simpler modal displacement approach may introduce significant errors in wing bending moments.QC 2012021