Investigating the Appropriateness of Fuzzy Logic Techniques to Model Unsteady Aerodynamics

The study of unsteady aerodynamics is highly critical due to its important impact on modern aircraft, in particular fighters, hence, modeling methods have been investigated and established. However, conventional methods, such as the least-square and maximum likelihood are not fully capable to predict all the required cases of unsteady aerodynamics at very high angle of attack and with complications from other factors such as severe weather conditions. Therefore, other methods should be investigated using artificial intelligence techniques. It is known that fuzzy logic, as a branch of artificial intelligence, can model unsteady and nonlinear systems in various areas such as control, stability, nonlinear stochastic system and coupled-unstable system. In this paper, the appropriateness of utilizing fuzzy logic to model unsteady aircraft aerodynamics was investigated. It is concluded that fuzzy modeling can reasonably model unsteady aerodynamics if the appropriate aerodynamic inputs, such as angle of attack and pitch rate are used. To establish a reliable model of unsteady aerodynamics using fuzzy model, it is important to utilize experimental data to train and test the FL model. The model can be further validated by comparison with mathematically obtained data.