This note presents simple methods to design fulland reducedorder proportional integral observer for unknown inputs (UI) descriptor systems. Sufficient conditions for the existence of the observer are given and proven. The observer is solvable by any pole placement algorithm, it achieves a posteriori robustness state and UI estimation versus to time varying parameters and bounded nonlinear UI. A...

Observer design for highly nonlinear dynamics is an important issue, particularly when the locally observable dynamics are not linearly observable. In such circumstances the ability to reduce the system to observable or observer form is a useful first step to observer design. We describe and illustrate symbolic computing tools to do that. 2005 Published by Elsevier Inc.

This paper deals with the observability analysis and the observer synthesis of a class of nonlinear systems. The observer that we consider has a constant gain and concerns a class of uniformly observable systems. A sufficient condition permitting to design such a constant gain observer is given. The calculation of this gain is based on LMI technics.Copyright c © 2008 IFAC

A novel model based scheme for the state estimation during anti-lock braking is presented based on a LuGre tyre model and a quarter car model. The wheel angular speed and longitudinal vehicle acceleration information are used to design a nonlinear observer based on the unscented Kalman filter theory. This nonlinear observer provides the necessary information for the anti-lock control despite th...

To handle the state estimation of a nonlinear system perturbed by a scalar disturbance distributed by a known nonlinear vector, we incorporate a sliding mode term into a nonlinear observer to realise a robust nonlinear observer. By linking the observability of the unknown input to the output measurement, the so-called matching condition is avoided. The measurable output estimation error is the ...

This paper aims at development of non linear dynamic model for Magnetic Levitation System and proposed linear and nonlinear state space controllers. The linear controller was designed by linearizing the model around equilibrium point, while nonlinear controller was based on feedback linearization where a nonlinear state-space transformation is used to linearize the system exactly. Relative degr...

A sliding mode control based on nonlinear disturbance observer is presented in this paper considering the tracking control of mobile manipulators. The proposed control strategy adopts the nonlinear observer to estimate the bounded external disturbances and overcome the effects. In addition, the stability of the controller is verified by Lyapunov theory. Finally, the simulation results verify th...

A general class of MIMO nonlinear systems with unknown inputs is considered with a view to observer synthesis. The particularity of this class of systems lies in the fact that the expression of the outputs depends on the unknown inputs. Different situations are considered and in each case a nonlinear observer, synthesized under appropriate hypotheses, is proposed to jointly estimate all state v...

This work focuses on developing nonlinear multirate model algorithmic controllers for nonlinear processes using a closed-loop observer. Conditions for the observer function and a gain corrector function, which is necessary to ensure that the resulting control structure has integral action, are given. The control action is calculated using the corrected states. The resulting structure is a two-d...

In this paper, we deal with the problem of the stabilization in the sample-andhold sense, by emulation of continuous-time, observer-based, global stabilizers. Fully nonlinear time-delay systems are studied. Sufficient conditions are provided such that the Euler approximation of continuous-time, observer-based, global stabilizers, for nonlinear time-delay systems, yields stabilization in the sam...