# Archives of Control Sciences

### Abstrakt

Abstract In this paper, the observer-based control for a class of uncertain linear systems is considered. Exponential stabilizability for the system is studied and reduced-order observer is discussed. Numerical examples are given to illustrate obtained results.
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### Abstrakt

Abstract The asymptotic stability of discrete-time and continuous-time linear systems described by the equations xi+1 = Ākxi and x(t) = Akx(t) for k being integers and rational numbers is addressed. Necessary and sufficient conditions for the asymptotic stability of the systems are established. It is shown that: 1) the asymptotic stability of discrete-time systems depends only on the modules of the eigenvalues of matrix Āk and of the continuous-time systems depends only on phases of the eigenvalues of the matrix Ak, 2) the discrete-time systems are asymptotically stable for all admissible values of the discretization step if and only if the continuous-time systems are asymptotically stable, 3) the upper bound of the discretization step depends on the eigenvalues of the matrix A.
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### Abstrakt

Abstract In the paper the extremal dynamic error x(τ) and the moment of time τ are considered. The extremal value of dynamic error gives information about accuracy of the system. The time τ gives information about velocity of transient. The analytical formulae enable design of the system with prescribed properties. These formulae are calculated due to the assumption that x(τ) is a function of the roots s1, ..., sn of the characteristic equation.
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### Abstrakt

Abstract This research work announces an eleven-term novel 4-D hyperchaotic system with two quadratic nonlinearities. We describe the qualitative properties of the novel 4-D hyperchaotic system and illustrate their phase portraits. We show that the novel 4-D hyperchaotic system has two unstable equilibrium points. The novel 4-D hyperchaotic system has the Lyapunov exponents L1 = 3.1575, L2 = 0.3035, L3 = 0 and L4 = −33.4180. The Kaplan-Yorke dimension of this novel hyperchaotic system is found as DKY = 3.1026. Since the sum of the Lyapunov exponents of the novel hyperchaotic system is negative, we deduce that the novel hyperchaotic system is dissipative. Next, an adaptive controller is designed to stabilize the novel 4-D hyperchaotic system with unknown system parameters. Moreover, an adaptive controller is designed to achieve global hyperchaos synchronization of the identical novel 4-D hyperchaotic systems with unknown system parameters. The adaptive control results are established using Lyapunov stability theory. MATLAB simulations are depicted to illustrate all the main results derived in this research work.
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### Abstrakt

Abstract The paper presents new approach to estimation of the coefficients of an elementary bilinear time series model (EB). Until now, a lot of authors have considered different identifiability conditions for EB models which implicated different identifiability ranges for the model coefficient. However, all of these ranges have a common feature namely they are significantly narrower than the stability range of the EB model. This paper proposes a simple but efficient solution which makes an estimation of the EB model coefficient possible within its entire stability range.
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### Abstrakt

Abstract In this paper, a multivariable model based predictive control (MPC) is proposed for the solution of load frequency control (LFC) in a multi-area interconnected power system. The proposed controller is designed to consider time delay, generation rate constraint and multivariable nature of the LFC system, simultaneously. A new formulation of the MPC is presented to compensate time delay. The generation rate constraint is considered by employing a constrained MPC and economic allocation of the generation is further guaranteed by an innovative modification in the predictive control objective function. The effectiveness of proposed scheme is verified through time-based simulations on the standard 39-bus test system and the responses are then compared with the proportional-integral controller. The evaluation of the results reveals that the proposed control scheme offers satisfactory performance with fast responses.
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### Abstrakt

Abstract In this paper, the state estimation problem for a class of mismatched uncertain time-delay systems is addressed. The estimation uses observer-based control techniques. The mismatched uncertain time-delay systems investigated in this study include mismatched parameter uncertainties in the state matrix and in the delayed state matrix. First, based on a new lemma with appropriately choosing Lyapunov functional, new results for stabilization of mismatched uncertain time-delay systems are provided on the basis of a linear matrix inequality (LMI) framework and the asymptotic convergence properties for the estimation error is ensured. Second, the control and observer gains are given from single LMI feasible solution which can overcome the drawback of the bilinear matrix inequalities approach often reported in the literature. Finally, a numerical example is used to demonstrate the efficacy of the proposed method.
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### Abstrakt

Abstract The paper provides the minimal necessary modifications of linear matrix inequality conditions for the mixed H2/H control design as well as for the augmented observer-based fault estimation to be mutually compatible in joint design of integrated fault estimation and fault tolerant control. To be possible, within this integration, to design the controller which guarantees a pre-specified H norm disturbance attenuation level, the design conditions has to be regularized using the H2 performance index and, moreover, augmented fault observer must be of enforced dynamics. Analyzing the ambit of performances given on the mixed H2/H design, the joint design conditions are formulated as a minimization problem subject to convex constraints expressed by a system of LMIs. The feasibility of the conditions is demonstrated by a numerical example.
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### Abstrakt

Abstract The stability problems of fractional discrete-time linear scalar systems described by the new model are considered. Using the classical D-partition method, the necessary and sufficient conditions for practical stability and asymptotic stability are given. The considerations are il-lustrated by numerical examples.
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### Abstrakt

Abstract This note addresses the stabilization problem of nonlinear chained-form systems with input time delay. We first employ the so-called σ-process transformation that renders the feedback system under a linear form. We introduce a particular transformation to convert the original system into a delay-free system. Finally, we apply a state feedback control, which guarantees a quasi-exponential stabilization to all the system states, which in turn converge exponentially to zero. Then we employ the so-called -type control to achieve a quasi-exponential stabilization of the subsequent system. A simulation example illustrated on the model of a wheeled mobile robot is provided to demonstrate the effectiveness of the proposed approach.
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### Redakcja

Editor-in-Chief prof. dr hab. inż. Andrzej Świerniak

Deputy/ Managing Editor
Zbigniew Ogonowski, Silesian University of Technology, Gliwice, Poland

Andrzej Bargiela, University of Nottingham, UK
Roman Barták, Charles University, Prague, Czech Rep.
Jacek Błażewicz, Poznań University of Technology, Poland
Reggie Davidrajuh, University of Stavanger, Norway
Andreas Deutsch, Technische Universität Dresden, Germany
Moritz Diehl, University of Freiburg, Germany
Władysław Findeisen, Warsaw University of Technology, Poland
Marcelo D.Fragoso, LNCC/MCT, Rio de Janeiro, Brasil
Avner Friedman, MBI Ohio State University, Columbus, USA
Alberto Gandolfi, IASI, Rome, Italy
Ryszard Gessing, Silesian University of Technology, Gliwice, Poland
Henryk Górecki, AGH University of Science and Technology, Poland
David Greenhalgh, University of Strathclyde, Glasgow, UK
Mats Gyllenberg, University of Helsinki, Finland
Raimo P. Hämäläinen, Aalto University School of Science, Finland
Alberto Isidori, Università di Roma "La Sapienza" Italia
Laszlo Kevicky, Hungarian Academy of Sciences, Hungary
Marek Kimmel, Rice University Houston, USA
Jerzy Klamka, Silesian University of Technology, Gliwice, Poland
Józef Korbicz, University of Zielona Góra, Poland
Irena Lasiecka, University of Virginia, USA
Urszula Ledzewicz, Southern Illinois University at Edwardsville, USA
Magdi S Mahmoud, KFUM, Dahram, Saudi Arabia
Krzysztof Malinowski, Warsaw University of Technology, Poland
Wojciech Mitkowski, AGH University of Science and Technology, Poland
Bozenna Pasik-Duncan, University of Kansas, Lawrence, USA
Ian Postlethwaite, Newcastle University, Newcastle, UK
Eric Rogers, University of Southampton, UK
Heinz Schaettler, Washington University, St Louis, USA
Ryszard Tadeusiewicz, AGH University of Science and Technology, Poland
Jan Węglarz, Poznań University of Technology, Poland
Liu Yungang, Shandong University, PRC
Valery D. Yurkevich, Novosibirsk State Technical University, Russia

### Kontakt

Institute of Automatic Control
Silesian University of Technology
44-101 Gliwice, Poland

### Instrukcje dla autorów

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1. R. E. Kalman: Mathematical description of linear dynamical system. SIAM J. Control. 1(2), (1963), 152-192.
2. F. C. Shweppe: Uncertain dynamic systems. Prentice-Hall, Englewood Cliffs, N.J. 1970.

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Papers should be sent to:

Zbigniew Ogonowski
Institute of Automatic Control
Silesian University of Technology