Aircraft Flutter Modal Parameter Identification

Flutter test data processing was the important component of flight flutter testing of aircraft. Because of the limits of test environment and measure conditions during flight flutter testing, the actual measured data were of poor quality for low signal-to-noise ratio, closely spaced modes, nonstationary and short effective samples, and added the difficulty of data processing. ARMAX model method and subspace-based state space method were used to process the flight flutter test data, and identify the flutter modal parameters of aircraft.Because the flutter model of aircraft was not known, the flutter model was needed to identify. First choose the flutter model of aircraft, identify the parameters of the model, then validate the identified model, and get the flutter modal parameters of aircraft by analyzing the frequency response function of the model at last. Two identification methods were used to compute the flutter modal parameters from the data, one was the ARMAX model method, and the other was subspace-based state space system identification method. Compared with the classical spectral estimate method, the two methods were very promising and feasible approaches in flight flutter test data processing.