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Automatic Control, IEEE Transactions on

Issue 4 • Date August 1981

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Displaying Results 1 - 25 of 38
  • [Front cover and table of contents]

    Page(s): 0
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    Freely Available from IEEE
  • In memoriam: Rufus P. Isaacs (1914-1981)

    Page(s): 809
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    Freely Available from IEEE
  • Editorial: Survey and tutorial papers

    Page(s): 810
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    Freely Available from IEEE
  • Correction to "State feedback decoupling with stability of linear constant (A,B,C,D) -Quadruples"

    Page(s): 974 - 975
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (182 KB)  

    The purpose of this note is to make a correction to a short paper which recently appeared in this TRANSACTIONS [1]. Although its main result (Theorem 4.1) remains valid, the proof given is incorrect. Here we restore the true nature of things. View full abstract»

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  • Large-scale dynamic systems: Stability and structure [Book reviews]

    Page(s): 976 - 977
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    Freely Available from IEEE
  • Foundations of mechanics, 2nd edition

    Page(s): 977 - 978
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    Freely Available from IEEE
  • [Back cover]

    Page(s): 0
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    Freely Available from IEEE
  • A root-clustering theorem

    Page(s): 940
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    We consider the problem of root clustering of a real matrix in an algebraic region of the complex plane. It is shown that a criterion (previously obtained) based on ann^{2} times n^{2}matrix reduces to a criterion based on anfrac{1}{2}n(n-1) times frac{1}{2}n(n-1)matrix. This is done for any transformable region and thus generalizes earlier results. View full abstract»

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  • A generalized state-space for singular systems

    Page(s): 811 - 831
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    Systems of the formEdot{x}=Ax + Bu, y=Cx, withEsingular, are studied. Of particular interest are the impulsive modes that may appear in the free-response of such systems when arbitrary initial conditions are permitted, modes that are associated with natural system frequencies at infinity. A generalized definition of system order that incorporates these impulsive degrees of freedom is proposed, and concepts of controllability and observability are defined for the impulsive modes. Allowable equivalence transformations of such singular systems are specified. The present framework is shown to overcome several difficulties inherent in other treatments of singular systems, and to extend, in a natural and satisfying way, many results previously known only for regular state-space systems. View full abstract»

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  • A general theory for matrix root-clustering in subregions of the complex plane

    Page(s): 853 - 863
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    We consider the general problem of root-clustering of a matrix in the complex plane: LetA in C^{n times n}andS subset C. Find the largest class ofSand an algebraic criterion which is necessary and sufficient forlambda_{i}[A] in S, i=1,2,..., n. We introduce two types of regions which constitute the largest class ofSknown to date. The criterion is presented both for open regions and closed ones. The results are used to define a design methodology for control systems. Moreover, all classical results are shown to be special cases of the present theory. View full abstract»

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  • Efficient time propagation of U-D covariance factors

    Page(s): 890 - 894
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    Time propagation of the Kalman filter covariance matrix involves an operation of the formPhi P Phi^{T}. For many applicationsPhihas a block triangular structure. When the filter implementation employsU-Dcovariance factorization (i.e., recursions forUandDare used, whereP=UDU^{T}, withUunit upper triangular andDdiagonal) this matrix structure can be used to reduce the computation cost of time propagation. The contribution of this paper is a streamlined Gram-Schmidt orthogonalization algorithm that can dramatically reduceU-Dtime update computation costs. View full abstract»

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  • Self-tuning minimum-variance control of nonlinear systems of the Hammerstein model

    Page(s): 959 - 961
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    Self-tuning is applied to the control of nonlinear systems represented by the Hammerstein model wherein the nonlinearity is any odd-order polynomial. But control costing is not feasible in general. Initial relay control is employed to contain the deviations. View full abstract»

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  • Calculation of the spectral density from the noise convolution integral covariance matrix

    Page(s): 969 - 970
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    A problem which arises in system identification of continuous systems with nonuniform sampling is that of calculating the spectral density of a vector white noise process from a noise convolution integral covariance matrix. A numerical solution to this problem is presented which converges in one step. View full abstract»

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  • A digital quality control system for an industrial dry process rotary cement kiln

    Page(s): 885 - 890
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    A multivariate autoregressive moving average (ARMA) model for an industrial dry process rotary cement kiln is identified, from real process data, using the maximum likelihood method. The model obtained is then used in computing a controller for quality control of clinker production. It is shown that it is relevant to compute a minimum variance controller subject to restrictions both in the controller structure and the variances of the control signals. The resulting controller is finally implemented on the cement kiln process, together with a target adaptive controller for automatic adjustment of the clinker quality setpoint, in order to save energy. View full abstract»

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  • The state representation of polynomic maps

    Page(s): 953 - 956
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    Letfbe an arbitrary strictly causal polynomic map between Hilbert resolution spaces. Thenfhas the formf=Ttauwhere τ is a predetermined causal map andTis linear and strictly causal. The mapsfandThave state representations. The present paper develops the interrelationship between these. View full abstract»

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  • New algorithms for unconstrained nonlinear optimal control problems

    Page(s): 868 - 884
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    A family of new first-order algorithms for solving continuous time optimal control problems is presented. The algorithms make use of the Riccati matrix differential equation and are capable of solving the linear quadratic problem in one step. The paper includes an analysis of the convergence of the proposed algorithms in the space of relaxed controls, as well as the proof of the reduction of the cost functional at each iteration and numerical examples. View full abstract»

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  • The computation of a transfer function matrix from the given state equations for time-delays systems

    Page(s): 949 - 951
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    An algorithm is established to compute the transfer function matrix from the state equations for linear multivariable system with constant noncommensurable delays. The proposed algorithm requires operations with constant matrices only and is suitable for computer programming. An example illustrating the proposed algorithm is given. View full abstract»

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  • Good feedback structure selection

    Page(s): 946 - 948
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB)  

    An approximate method of calculating the contributions of the gains in a feedback structure is produced. The discrete time, linear, quadratic state feedback problem is considered. By state and control augmentation dynamic compensators with fixed and tunable parameters including decentralized and hierarchical structures can also be handled. An example is used to illustrate the usefulness of the approach in selecting good simplified feedback structures and to verify the reasonableness of the assumptions. View full abstract»

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  • A note on the Lyapunov matrix equation

    Page(s): 941 - 942
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    In [5] bound for the determinant of the solution to the Lyapunov matrix equation was reported. This note gives an another bound for this value. View full abstract»

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  • On the convergence of an iterative algorithm used for Hammerstein system identification

    Page(s): 967 - 969
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    An analytical counterexample to the general convergence of an interative algorithm used for identification of Hammerstein systems is given. Numerical illustration is also included. View full abstract»

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  • Stability of time-delay systems

    Page(s): 951 - 953
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    This paper gives necessary and sufficient conditions for the stability of time-delay systems of the formdot{x}(t)=A_{1}x(t)+A_{2}x(t-h). These new conditions are derived by Lyapunov's direct method through systematic construction of the corresponding "energy" function. This function is known to exist, if a solutionP_{1}(0)of the algebraic nonlinear matrix equationA_{2} =e^{[A_{1}+P_{1}(0)]h}P_{1}(0)can be determined. View full abstract»

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  • Homogeneous interconnected systems: An example

    Page(s): 894 - 901
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    Large systems with special invariance properties appear in many engineering problems, e.g., solar arrays, cascades of reactors, flexible structures, etc. In this paper, we are concerned with a class of such systems exhibiting a linear lattice structure. Following some observations on the algebraic structure of such systems, we focus on the analytic aspects of associated control problems. Our motivation for this exercise derives from problems of controlling seismic cables used in offshore oil exploration. View full abstract»

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  • Identifiability of unknown noise covariance matrices for some special cases of a linear, time-invariant, discrete-time dynamic system

    Page(s): 970 - 974
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    This paper investigates the identification of unknown noise covariance matricesQandRof an LTI discrete-time dynamic system. Two algorithms based on maximum a posteriori (MAP) and maximum likelihood (ML) cost functions are evaluated. It is demonstrated that the cost functions exhibit local minima versus those elements ofQandRwhich dominate the steady-state output covariance matrix. The following three special cases are considered: 1) single-input single-output (SISO) system; 2) multiinput single-output (MISO) systems; and 3) single-input multioutput (SIMO) systems with a diagonalR. For these special cases, specific identifiability criteria are presented and verified by examples. The improvement of the MAP algorithm over the ML algorithm is also demonstrated. View full abstract»

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  • Additions of interactive fuzzy numbers

    Page(s): 926 - 936
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    This paper provides an account of an approach to modeling unknown data by means of fuzzy-set theory, and addresses the problem of deriving the uncertainty, on a sum of variables whose values lie within fuzzy intervals. The first part is an extensive presentation of the theoretical background of the approach: the extension principle is stated in terms of possibility of an event; the concept of variable interaction is investigated at length. Section II gives new results regarding the effective practical computation of additions of fuzzy numbers. Its originality lies in the introduction of interaction which enables to control the growth of uncertainty, in calculations. Moreover, the problem of computing mathematical expectations with fuzzy probabilities is solved. The results derived in this paper can easily be used in decision problems where values of parameters or decision variables are not yet precisely fixed or assessed. Typical applications could be multicriteria optimization and decision making under uncertainty where fuzzy expected utilities can be obtained out of uncompletely assessed probabilities. More generally, fuzzy arithmetic can be an important tool for sophisticated, computationally tractable sensitivity analysis in systems modeling, computer-aided design and operations research. View full abstract»

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Aims & Scope

In the IEEE Transactions on Automatic Control, the IEEE Control Systems Society publishes high-quality papers on the theory, design, and applications of control engineering.  Two types of contributions are regularly considered

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Meet Our Editors

Editor-in-Chief
P. J. Antsaklis
Dept. Electrical Engineering
University of Notre Dame