Fuzzy logic based unsteady aerodynamics modeling and analysis of advanced aircraft

In this paper, an accurate unsteady aerodynamic model of advanced aircraft flying at high angle of attack is established based on the fuzzy logic method. Firstly, on the basis of processing wind tunnel test data, the unsteady aerodynamic characteristics under large single-axis oscillation are compared and analyzed, and the key factors affecting the unsteady aerodynamic modeling are extracted. Secondly, the membership function, internal function, fuzzy rules, model input and output of the fuzzy logic model are determined. Finally, based on the idea of back substitution method, the parameters obtained by Newton gradient iteration method are treated as the initial values of the parameters for the next structural identification, thus the improved model structure and parameters are proposed. The identification algorithm determines the structure of the model while constantly seeking the parameters of the model in view of the accuracy requirement of the model. The simulation results show that the unsteady aerodynamic modeling method proposed in this paper has strong applicability and high modeling accuracy.