When prior knowledge of the plant controlled is available, feedforward control is preferred over feedback control for disturbance rejection. The stability characteristics of the system using feedforward control are the same as the original plant. Adaptive feedforward control design for gust loads alleviation of both a two degrees of freedom aerofoil with polynomial structural nonlinearity and a free flying flexible aircraft with large geometric wing deformations is investigated. Two dimensional thin aerofoil theory based on Theodorsen theory is used to perform aerodynamic analysis in the aerofoil aeroelastic model. The same aerodynamic model coupled with geometrically exact nonlinear beam is used to formulate the multi-disciplinary fluid-structure-flight framework for highly flexible aircraft. Gust loads analysis in terms of both discrete and continuous turbulence gusts are performed based on the aerofoil model and the free flying trim configuration of the highly flexible aircraft. Finite impulse response model is used to design an adaptive feedforward controller to alleviate the gust loads. Adaptive feedforward control shows good gust loads alleviation performance for both discrete and continuous gusts. Compared with adaptive feedback control, it exhibits a greater potential to reduce gust loads from the initial transient of the encounter.

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