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LMI Conditions (lmi + condition)

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Engineering	100%

Selected Abstracts

Further results on delay-dependent robust stability conditions of uncertain neutral systems

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 5 2005
Shengyuan Xu
Abstract This paper deals with the problem of robust stability analysis for uncertain neutral systems. In terms of a linear matrix inequality (LMI), an improved delay-dependent asymptotic stability criterion is developed without using bounding techniques on the related cross product terms. Based on this, a new delay-dependent LMI condition for robust stability is obtained. Numerical examples are provided to show that the proposed results significantly improve the allowed upper bounds of the delay size over some existing ones in the literature. Copyright © 2005 John Wiley & Sons, Ltd. [source]

A new absolute stability test for systems with state-dependent perturbations

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 14 2002
M. C. de Oliveira
Abstract In this paper, a new test for the absolute stability of nonlinear systems with state-dependent nonlinearities is developed. Scalar nonlinearities are assumed to lie in sectors. Using a Lur'e function as a Lyapunov function, a linear matrix inequalities (LMI) stability condition is derived. The new condition lets one go from a pure integral (Persidskii) to a pure quadratic Lyapunov function in an unified framework. Several results available in the literature are generated as particular cases of the new test. An example shows that the proposed condition can be much less conservative than available diagonal stability and passivity based methods, as the circle and Popov criteria. Tests for infinite as well as finite nonlinearity sectors can be easily generated, since the parameters of the nonlinearity sectors appear in the LMI condition in a very convenient way. This feature can also provide optimization of the absolute stability sector through convex programming techniques. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Delay-dependent robust stability and stabilization for uncertain discrete singular systems with delays ,,

ASIAN JOURNAL OF CONTROL, Issue 3 2009
Shuping Ma
Abstract The robust stability and robust stabilization for time-delay discrete singular systems with parameter uncertainties is discussed. A delay-dependent linear matrix inequality (LMI) condition for the time-delay discrete systems to be nonsingular and stable is given. Based on this condition and the restricted system equivalent transformation, the delay-dependent LMI condition is proposed for the time-delay discrete singular systems to be admissible. With this condition, the problems of robust stability and robust stabilization are solved, and the delay-dependent LMI conditions are obtained. Numerical examples illustrate the effectiveness of the method given in the paper. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source]

Robust ,2 -gain feedforward control of uncertain systems using dynamic IQCs

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 11 2009
I. E. Köse
Abstract We consider the problem of robust ,2 -gain disturbance feedforward control for uncertain systems described in the standard LFT form. We use integral quadratic constraints (IQCs) for describing the uncertainty blocks in the system. For technical reasons related to the feedforward problem, throughout the paper, we work with the duals of the constraints involved in robustness analysis using IQCs. We obtain a convex solution to the problem using a state-space characterization of nominal stability that we have developed recently. Specifically, our solution consists of LMI conditions for the existence of a feedforward controller that guarantees a given ,2 -gain for the closed-loop system. We demonstrate the effectiveness of using dynamic IQCs in robust feedforward design through a numerical example. Copyright © 2008 John Wiley & Sons, Ltd. [source]

,2 -Stabilization of continuous-time linear systems with saturating actuators

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 18 2006
E. B. Castelan
Abstract This paper addresses the problem of controlling a linear system subject to actuator saturations and to ,2 -bounded disturbances. Linear matrix inequality (LMI) conditions are proposed to design a state feedback gain in order to satisfy the closed-loop input-to-state stability (ISS) and the closed-loop finite gain ,2 stability. By considering a quadratic candidate Lyapunov function, two particular tools are used to derive the LMI conditions: a modified sector condition, which encompasses the classical sector-nonlinearity condition considered in some previous works, and Finsler's Lemma, which allows to derive stabilization conditions which are adapted to treat multiple objective control optimization problems in a potentially less conservative framework. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Stability analysis and guaranteed domain of attraction for a class of hybrid systems: an LMI approach

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 5 2003
S. Palomino Bean
Abstract This paper presents sufficient conditions for the regional stability problem for switched piecewise affine systems, a special class of Hybrid Systems. This class of systems are described by an affine differential equation of the type x,=A(,)x+b(,), where x denotes the continuous state vector and , is a vector of logical variables that modifies the local model of the system in accordance with the continuous dynamics. Using a Lyapunov function of the type v(x)=x,P(x)x, we present LMI conditions that, when feasible, guarantee local stability of the origin of the switched system. Examples of switched affine systems are used to illustrate the results. Copyright © 2003 John Wiley & Sons, Ltd. [source]