Feedback stabilization of nonlinear systems via center manifold reduction

The center manifold theorem is applied to the local feedback stabilization of nonlinear systems in critical cases. The authors address two particular critical cases, for which the system linearization at the equilibrium point of interest is assumed to possess either a simple zero eigenvalue or a complex conjugate pair of simple, pure imaginary eigenvalues. In either case, the noncritical eigenvalues are taken to be stable. The results on stabilizability and stabilization are given explicitly in terms of the nonlinear model of interest in its original form, i.e. before reduction to the center manifold. Moreover, the formulation given uncovers connections between results obtained using the center manifold reduction and those of an alternative approach