Abstract: This paper provides new developments in the design of observers for nonlinear systems with unknown inputs. The proposed methods guarantee the error system stability and yield many additional degrees of freedom available to the designer. The algorithms for designing a nonlinear observer for nonlinear systems with unknown inputs is derived in detail. The proposed observers may be used f...

In this works, we use the approach based on observers such as the Luenberger observer and the sliding mode observer in order to introduce the diagnosis of nonlinear systems. The robustness of the proposed observers is tested through a physical example. The obtained results show that for non linear systems the performances of sliding mode observer observer is better than using a classic kind of ...

The problem of observer-based fault diagnosis of a certain class of nonlinear dynamic systems is studied. To solve this problem, the following approach is suggested: replacing the initial nonlinear system by certain linear logic-dynamic system, obtaining the bank of linear logic-dynamic observers, and transforming these observes into the nonlinear ones. The procedure of the linear logic-dynamic...

This paper shows how the theory of nonlinear adaptive observers can be effectively used in the design of internal models for nonlinear output regulation. The theory substantially enhances the existing results in the context of adaptive output regulation, by allowing for not necessarily stable zero dynamics of the controlled plant and by weakening the standard assumption of having the steady sta...

A constructive method is proposed for the design of nonlinear adaptive observers with global convergence for recursive joint estimation of states and parameters. It extends an earlier result to systems with a more general parametrization. The considered nonlinear systems are those typically considered for the design of high gain observers with additional terms involving unknown parameters. A nu...

This paper considers the state observation problem for autonomous nonlinear systems. An observation mapping is introduced, which is defined by applying a linear integral operator (rather than a differential operator) to the output of the system. It is shown that this observation mapping is well suited to capture the observability nature of smooth as well as nonsmooth systems, and to construct o...

A set-valued observer (SVO) produces a set of possible states based on output measurements and a priori models of exogenous disturbances and noises. Previous work considered linear time-varying systems and unknown-but-bounded exogenous signals. In this case, the sets of possible state vectors take the form of polytopes whose centers are optimal state estimates. These polytopic sets can be compu...