Nonlinear aeroelastic system identification with application to experimental data

Representation and identification of a nonlinear aeroelastic pitch-plunge system as a model of the NARMAX class is considered. A nonlinear difference equation describing this aircraft model is derived theoretically and shown to be of the NARMAX form. Identification methods for NARMAX models are applied to aeroelastic dynamics and their properties demonstrated via continuous-time simulations of experimental conditions. Simulation results show that 1) the outputs of the NARMAX model closely match those generated using continuous-time methods and 2) NARMAX identification methods applied to aeroelastic dynamics provide accurate discrete-time parameter estimates. Application of NARMAX identification to experimental pitch-plunge dynamics data gives a high percent fit for cross-validated data.