T-Accessibility for a class of nonlinear time–delay systems
Observability and detectability on one hand as well as accessibility and controllability on the other, are related properties and have not been closely investigated for nonlinear–time delay systems until these recent years. Currently accessibility or nonlinear time delay systems is defined as the absence of autonomous functions on the extended state space. Such a property is expressed in terms of the Accessibility matrix rank, extending to the nonlinear context the well known Kalman Criterion.