Input and State Observability of Network Systems with a Single Unknown Input

Nonlinear Unknown Input Observability: Extension of the Observability Rank Condition and the Case of a Single Unknown Input

This paper investigates the unknown input observability problem in the nonlinear case under the assumption that the unknown inputs are differentiable functions of time (up to a given order). The goal is not to design new observers but to provide simple analytic conditions in order to check the weak local observability of the state. The analysis starts by extending the observability rank conditi...

Nonlinear Unknown Input Observability: Analytical expression of the observable codistribution in the case of a single unknown input

Input and State Functional Observability for Descriptor Systems

This paper deals with the right-hand side observability of a linear function of the state and the unknown inputs for linear systems in descriptor form. For such systems, necessary and sufficient conditions ensuring the ability of reconstructing any given functional of the state and unknown inputs are determined by means of geometrical tools like subspace sequences. Copyright c ©2005 IFAC

Observability of switching structured linear systems with unknown input. A graph-theoretic approach

This paper deals with the observability of the discrete mode, the internal state and the input of switching structured linear systems with unknown input. The proposed method, based on a graph-theoretic approach, assumes only the knowledge of the system’s structure. We express, in graphical terms, necessary and sufficient conditions for the generic observability of the discrete mode, the continu...

Observability of Nonlinear Input-Affine Systems

The main aim of this paper is to characterize the set of states indistinguishable from a given state of a general nonlinear input-affine control system with complete and smooth vector fields and smooth output functions. For this purpose, we introduce the extended observation space, and show that the set of states indistinguishable from a given state is the intersection of level sets containing ...