Multiharmonic excitation for nonlinear system identification

Parametric identification of nonlinear systems is done using a hybrid time/frequency-domain-based Fourier series identification method. A multiharmonic force excitation is proposed to overcome identification problems encountered with a single harmonic excitation for certain classes of nonlinear systems. A Duffing oscillator and a system with quadratic damping are considered in detail for illustration of the proposed identification scheme using multiharmonic excitation. It is demonstrated that for most situations a multiharmonic excitation leads to significantly better identification results than a single harmonic excitation-based method.