Disturbance observers and applications

Set-valued observers and optimal disturbance rejection

A set-valued observer (also called guaranteed state estimator) produces a set of possible states based on output measurements and models of exogenous signals. In this paper, we consider the guaranteed state estimation problem for linear timevarying systems with a priori magnitude bounds on exogenous signals. We provide an algorithm to propagate the set of possible states based on output measure...

Estimation and Compensation of Nonlinear Perturbations by Disturbance Observers

Using Tracking Differentiators in Designing Nonlinear Disturbance Observers for Uncertain Systems

Using Tracking Differentiators in Designing Nonlinear Disturbance Observers for Uncertain SystemsNaser Kazemzadeh, Saeed BarghandanAbstractIn the present paper, a practical designing method has been proposed for a novel class of NDOs based on TD. Such NDOs can nearly estimate all uncertain disturbances (specifically disturbances without prediction information). Regarding the outstanding perform...

Disturbance Decoupled Fault Reconstruction Using Sliding Mode Observers

The objective of a robust fault reconstruction scheme is to generate an accurate reconstruction of the fault that is unaffected by disturbances. A typical method for robust fault reconstruction is to reconstruct the faults and disturbances, which is conservative and requires stringent conditions. This paper investigates and presents conditions that guarantee a fault reconstruction that rejects ...

On disturbance decoupled observers for a class of bilinear systems

In this paper, the class of bilinear systems subjected to unknown inputs for which there exists a disturbance decoupled observer with linear error dynamics is characterised. It is shown that the design of this kind of observer is equivalent to the design of a disturbance decoupled observer for a linear system. This result simplifies considerably the observer design comparatively to those propos...