Bilinear approximation and identification for nonlinear system modeling

A bilinear approximation technique for identification of a class of nonlinear dynamical models is presented, It is shown that for bilinear systems with a stable drift term the natural space of input-output models is that of causal Fock functionals. The functional spline interpolators hence obtained are found to have time-varying but asymptotically stable and decoupled bilinear realizations. Motivation is given by the need for systems order reduction and input-output analysis of Carleman bilinearization, with application to the attitude dynamics of a rigid spacecraft