2,491 research outputs found
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Robust H2/H∞-state estimation for discrete-time systems with error variance constraints
Copyright [1997] IEEE. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.This paper studies the problem of an H∞-norm and variance-constrained state estimator design for uncertain linear discrete-time systems. The system under consideration is subjected to
time-invariant norm-bounded parameter uncertainties in both the state and measurement matrices. The problem addressed is the design of
a gain-scheduled linear state estimator such that, for all admissible measurable uncertainties, the variance of the estimation error of each state is not more than the individual prespecified value, and the transfer function from disturbances to error state outputs satisfies the prespecified H∞-norm upper bound constraint, simultaneously. The conditions for the existence of desired estimators are obtained in terms of matrix inequalities, and the explicit expression of these estimators is also derived. A numerical example is provided to demonstrate various aspects of theoretical results
Comment on ``Understanding the scalar meson quark-antiquark nonet''
It is shown that the incomplete scalar meson nonets found by Toernqvist (T)
and Toernqvist and Roos (TR), employing a new version of the Helsinki
unitarised quark model, should in fact be complete, including an as yet
unconfirmed light K*0 below 1 GeV (old kappa) and the established f0(1500). A
detailed comparison is presented with the predictions of the Nijmegen
unitarised meson model, in which two complete scalar nonets show up below 1.5
GeV. The reason for the flavour-nonet breaking found in T and TR we argue to
originate in the use of coupling constants for the three-meson vertex which are
not independent of flavour. Also some statements made by Toernqvist are
critically reviewed.Comment: 10 pages, plain LaTeX, extension (more detailed on pole doubling and
f0(1500) interpretation) and cosmetic
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Disturbance and Input-Output Decoupling of Systems
The disturbance decoupling and the simultaneous disturbance and input–output decoupling problems for singular systems are considered in the context of the matrix fraction description (MFD) of the system. Solvability conditions are obtained in terms of the composite matrix of a column reduced MFD of the system, a characterisation of the fixed poles of both problems is given and it is shown that the remaining poles can be arbitrarily assigned
H infinity control design for generalized second order systems based on acceleration sensitivity function
This article presents an Hinfinty control design method based on the Acceleration Sensitivity (AS) function. This approach can be applied to any fully actuated generalized second order system. In this framework, classical modal specifications(pulsations / damping ratios) are expressed in terms of Hinfinty templates allowing other frequency domain specifications to betaken into account. Finally, a comparison between AS with a more classical Hinfinty approach and with the Cross Standard Form(CSF) is presented. A 2 degrees of freedom spring-damper-mass academic example is used to illustrate the properties of the AS,though this method was developed and is used for atmospheric reentry control design
A direct approach to the design of linear multivariable systems
Design of multivariable systems is considered and design procedures are formulated in the light of the most recent work on model matching. The word model matching is used exclusively to mean matching the input-output behavior of two systems. The term is used in the frequency domain to indicate the comparison of two transfer matrices containing transfer functions as elements. Design methods where non-interaction is not used as a criteria were studied. Two design methods are considered. The first method of design is based solely upon the specification of generalized error coefficients for each individual transfer function of the overall system transfer matrix. The second design method is called the pole fixing method because all the system poles are fixed at preassigned positions. The zeros of terms either above or below the diagonal are partially fixed via steady state error coefficients. The advantages and disadvantages of each method are discussed and an example is worked to demonstrate their uses. The special cases of triangular decoupling and minimum constraints are discussed
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Approximate zero polynomials of polynomial matrices and linear systems
This paper introduces the notions of approximate and optimal approximate zero polynomial of a polynomial matrix by deploying recent results on the approximate GCD of a set of polynomials Karcaniaset al. (2006) 1 and the exterior algebra Karcanias and Giannakopoulos (1984) 4 representation of polynomial matrices. The results provide a new definition for the "approximate", or "almost" zeros of polynomial matrices and provide the means for computing the distance from non-coprimeness of a polynomial matrix. The computational framework is expressed as a distance problem in a projective space. The general framework defined for polynomial matrices provides a new characterization of approximate zeros and decoupling zeros Karcanias et al. (1983) 2 and Karcanias and Giannakopoulos (1984) 4 of linear systems and a process leading to computation of their optimal versions. The use of restriction pencils provides the means for defining the distance of state feedback (output injection) orbits from uncontrollable (unobservable) families of systems, as well as the invariant versions of the "approximate decoupling polynomials". The overall framework that is introduced provides the means for introducing measures for the distance of a system from different families of uncontrollable, or unobservable systems, which may be feedback dependent, or feedback invariant as well as the notion of "approximate decoupling polynomials"
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