Design Of Full-order State Observers Research Articles

An Observer-Based Robust Load Frequency Control

A full-order observer-based state feedback linear controller design approach for a single area load frequency problem is presented. The load frequency control model incorporates integral control for improved command tracking response and disturbance rejection. A full state feedback is implemented through full-order state observer design. State feedback with integral controllers design is carried out through a pole-placement technique using symmetrical root locus method. Parametric model uncertainty has been considered and stability robustness study has been carried out assigning a bound on the deviations in parameters of single area load frequency model. The proposed design methodology achieves performance satisfying the specified stability margins. The methodology provides a control over peak values of the frequency and control signal deviations which may be utilized to meet hardware constraints. A numerical example illustrates the effectiveness of the developed methodology.

Robust fault detection in linear systems based on full-order state observers

A parametric approach to robust fault detection in linear systems with unknown disturbances is presented. The residual is generated using full-order state observers (FSO). Based on an analytical solution to a type of Sylvester matrix equations, the parameterization of the observer gain matrix is given. In terms of the design degrees of freedom provided by the parametric observer design and a group of introduced parameter vectors, a sufficient and necessary condition for full-order state observer design with disturbance decoupling is then established. By properly constraining the design parameters according to this proposed condition, the effect of the disturbance on the residual signal is also decoupled, and a simple algorithm is developed. The presented approach offers all the degrees of design freedom. Finally, a numerical example illustrates the effect of the proposed approach.

SET-INVARIANT ESTIMATORS FOR LINEAR SYSTEMS SUBJECT TO DISTURBANCES AND MEASUREMENT NOISE

The concept of set-invariance is applied to the design of full-order state observers with limitation of the estimation error, for discrete-time linear systems subject to unknown but bounded persistent disturbances and measurement noise. It is shown that if the initial error belongs to a D-(C, A)-invariant set, then it can be kept in this set by means of a suitable output injection, for all admissible disturbances and noise. Polyhedral D-(C, A)-invariant sets are explicitly characterized by necessary and sufficient conditions. Based on such conditions, algorithms are proposed for the computation of a D-(C, A)-invariant polyhedron containing the one to which the initial error belongs. The results are illustrated and compared to other approaches by means of a numerical example.

(C,A)-Invariant Polyhedra and Design of State Observers with Error Limitation

The concept of (C,A)-invariant sets is analyzed, together with its application to the design of full-order state observers with limitation of the estimation error, for discrete-time linear systems. If the initial error belongs to a (C,A)-invariant set, then it can be kept in this set by means of a suitable observation law. Polyhedral (C,A)-invariant sets are explicitly characterized by necessary and sufficient conditions. Based on such conditions, an algorithm is proposed for the computation of a (C,A)-invariant polyhedron containing the one to which the initial error belongs. An observation law which guarantees the bounds on the error is also proposed. The results are illustrated by a numerical example.