Nonparametric subspace identification of nonlinear structures - Application to a spacecraft

The objective of the present paper is to address the identification of a strongly nonlinear
satellite structure by exploiting a new nonlinear subspace identification method formulated
in the frequency domain, referred to as the FNSI method. The modal parameters of
the underlying linear structure and the coefficients of the nonlinear internal forces will
be estimated by this approach. Moreover, because a priori knowledge about nonlinear
behaviour may be limited, the paper also proposes a nonparametric spline-based modelling
strategy, encapsulated in the FNSI method. The application of interest is the SmallSat
spacecraft developed by EADS-Astrium, which possesses an impact-type nonlinear device
consisting of eight mechanical stops limiting the motion of an inertia wheel mounted on an
elastomeric interface.