화학공학소재연구정보센터
Automatica, Vol.64, 226-233, 2016
Controlled invariance for nonlinear differential-algebraic systems
We study the concept of locally controlled invariant submanifolds for nonlinear differential-algebraic/descriptor systems. In contrast to classical approaches, we define controlled invariance as the property of solution trajectories to evolve in a given submanifold whenever they start in it. It is then proved that this concept is equivalent to the existence of a feedback which renders the closed-loop vector field invariant in the descriptor sense. This result is exploited to show that the outcome of the differential-algebraic version of the zero dynamics algorithm yields a maximal output zeroing submanifold. The latter is then used to characterize the zero dynamics of the system. In order to guarantee that the zero dynamics are locally autonomous (i.e., locally resemble the behavior of an autonomous dynamical system), sufficient conditions involving the locally maximal output zeroing submanifold are derived. (C) 2015 Elsevier Ltd. All rights reserved.