Flight Control for Very Flexible Aircraft Using Model-Free Adaptive Control

摘要

A cascaded proportional-derivative model-free adaptive controlapproach has been proposed to accommodate the model-freeadaptive control scheme in a flight control problem, which also offersbetter control performance than the originalMFAC approach throughintroducing necessary damping effects. Simulation results show thatthe proposedmodel-free flight control systemis able to achieve desirablegust load alleviation response and efficient path following in threedimensions. The PD-MFAC control system also has better effectivenessand robustness (against disturbance rejection and modeling uncertainties)as compared to a baseline H_∞ control system. This is because of thefollowing:1) The H_∞ control design is based on a linear reduced-ordermodel, in which there exist modeling errors and unmodeleddynamics with respect to the nonlinear aeroservoelastic system.Thus, its performance degrades when applied to the nonlinearsystem: in particular, for the case where the practical parameters havelarge deviations from those used in the modeling process.