The output stabilization problem for a linear system with an unknown bounded time-varying input delay is considered. The interval observation technique is applied in order to obtain guaranteed interval estimate of the system state. The procedure of the interval observer synthesis uses lower and upper estimates of the unknown delay and requires to solve a special Silvester’s equation. The interv...

This paper deals with the unknown input observer (UIO) design problem for a class of linear time-delay systems. A case in which the observer error can completely be decoupled from an unknown input is treated. Necessary and sufficient conditions for the existences of such observers are present. Based on Lyapunov stability theory, thedesign of the observer with internal delay is formulated in ter...

This paper presents a linear matrix inequality (LMI) approach for designing a robust decentralized structure constrained controller for power systems. The problem of designing a fixed-structure H2/H∞ dynamic output feedback controller is first reformulated as an extension of a static output feedback controller design problem for the extended system. The resulting optimization problem has biline...

In view of the conservatism of the conventional linear matrix inequality (LMI) based fault detection observer design for Takagi-Sugeno fuzzy nonlinear systems with more If-Then rules, an improved fuzzy observer design is presented. The identical transformation of matrix inequalities is employed to reduce the conservatism and the number of LMI constraints, which can accommodate to the models wit...

A static-rate-feedback control for collocated structural systems is considered in this paper. The feedback gain matrix is obtained by solving linear matrix inequalities (LMIs) to minimize an upper bound of the closed-loop HN or H2 norm. The LMI conditions are obtained by assuming the form of Lyapunov matrices in the standard LMI conditions for evaluating the HN or H2 norm. We demonstrate that t...

This paper considers a control synthesis problem for linear systems to meet design specifications given in terms of multiple frequency domain inequalities in (semi)finite ranges. Dynamic output feedback controllers of order equal to the plant are considered. A new multiplier expansion is proposed to convert the synthesis condition to a linear matrix inequality (LMI) condition through the linear...

Dry-friction oscillators are mechanical systems with dry friction and stick-slip vibrations. In the context of control theory, the stability analysis of this type of dynamical systems is important since they exhibit non-smooth bifurcations, or most famously a sliding-grazing bifurcation inducing abrupt chaos. This paper develops a Lyapunovbased framework to study the so-called structural stabil...

Linear matrix inequalities (LMIs) play a fundamental role in robust and optimal control theory. However, their practical use remains limited, in part because their solution complexities of O(n) time and O(n) memory limit their applicability to systems containing no more than a few hundred state variables. This paper describes a Newton-PCG algorithm to efficiently solve large-and-sparse LMI feas...

For continuous-time, linear descriptor system with state-delay a H∞-control problem is solved. Sufficient conditions for delay-dependent/delay-independent stability and L2-gain analysis are obtained in terms of linear matrix inequalities (LMIs). A bounded real lemma and state-feedback solutions are derived for systems which may contain polytopic parameter uncertainties. The filtering problem is...

Given a global nonlinear state feedback which stabilizes globally an equilibrium, the aim of this paper is to modify the local behavior of the trajectories in order to get local optimality with respect to a given quadratic cost. A sufficient condition is given in terms of Linear Matrix Inequalities (LMI) to design a locally optimal and globally stabilizing control law. This approach is illustra...