Nonlinear noninteraction with stability by dynamic state feedback

The dynamic feedback noninteraction with stability problem for square affine systems with a nonsingular decoupling matrix is investigated. First, a characterization of the class of dynamic feedbacks resulting in a noninteractive system is given. It is then shown that these feedbacks induce a certain subdynamic, which is determined by the given system alone and independent of the particular feedback used. The stability of this subdynamic is necessary for the achievement of noninteraction with stability. This condition extends an analogous result on the static feedback noninteraction with stability problem obtained recently by Isidori and Grizzle.