We consider a two degree of freedom airfoil oscillating in pitch and plunge, with either polynomial or freeplay structural non-linearities. Using only a limited amount of transient noisy data, we present a new approach based on the expectation maximization algorithm, for parameter estimation, filtering and prediction. For systems with polynomial nonlinearities the expectation maximization algorithm is constructed using the unscented filter, and is illustrated for experimental data. For the freeplay case we use switching linear Kalman filters and results with simulated data are reported.

Back