A canonical dynamic extension for noninteraction with stability for nonlinear systems

The problem of noninteracting control with stability via dynamic feedback is considered for nonlinear systems with two inputs and two outputs. Given a system which may not be capable of decoupling via static state feedback but is capable of decoupling via dynamic feedback, a canonical dynamic extension is constructed. It is shown that every dynamic extension contains this canonical one. Hence, the Δ_mix dynamics as defined by K. Wagner (1989) of the canonical extension is contained in every other dynamic extension. Following Wagner´s result, the stability of this Δ_mix dynamics is necessary for noninteraction with internal stability. The results obtained show that in the investigation of noninteraction with stability one can assume without loss of generality that the system is capable of decoupling via static state feedback