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Automatic Control, IEEE Transactions on

Issue 4 • Date April 1987

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Displaying Results 1 - 22 of 22
  • [Front cover and table of contents]

    Publication Year: 1987 , Page(s): 0
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    Freely Available from IEEE
  • Scanning the issue

    Publication Year: 1987 , Page(s): 273
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  • Editorial: Research directions: A first step

    Publication Year: 1987 , Page(s): 274
    Cited by:  Papers (3)
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    Freely Available from IEEE
  • [Back cover]

    Publication Year: 1987 , Page(s): 0
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  • Remarks on stochastic model reduction

    Publication Year: 1987 , Page(s): 356 - 358
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (336 KB)  

    In this note, we give a solution to the stochastic system model reduction problem in terms of the approximation of the output stochaslic process power spectrum by applying balanced realization or optimal Hankel norm approximation to the asymptotically stable and minimum phase spectral factor. We also give explicit bounds for the approximation error. The effectiveness of this method is compared to the one by Jonckheere and Helton. View full abstract»

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  • Lyapunov-like equations and reachability/observabiliy Gramians for descriptor systems

    Publication Year: 1987 , Page(s): 343 - 348
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (616 KB)  

    Reachability and observability Gramians are defined for the descriptor systems Ex_{k-1} = Ax_{k} + Bu_{k}, y_{k} = Cx_{k} and E\dot{x}(t) = Ax(t) + Bu(t), y(t) = Cx(t) . The pencils (zE - A) and (sE - A) are assumed to be regular. If E is singular,these Gramians do not, in general, satisfy the "expected" Lyapunov-like (Sylvester) equations (for example, EPA^{T} + APE^{T} = - BB^{T} if P is the continuous-time teachability Gramian). This is shown by expressing the solution of the descriptor system in terms of the parameters of the Laurent expansion of (zE - A)^{-1} or (sE - A)^{-1} . We derive the Lyapunov-like equations which these Gramians do satisfy. View full abstract»

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  • ARMA order estimation via matrix perturbation theory

    Publication Year: 1987 , Page(s): 358 - 361
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    Using matrix perturbation theory, we obtain the statistical distribution of the smallest eigenvalue of the Hankel matrix built upon the estimated covariances, under the hypothesis that the corresponding exact Hankel matrix possesses one single zero eigenvalue. This allows us to develop and justify a new order determination scheme, whose performance appears similar to those based on likelihood maximization, but with a much lower computational complexity. View full abstract»

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  • A necessary and sufficient condition for stability of a perturbed system

    Publication Year: 1987 , Page(s): 337 - 340
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (344 KB)  

    The problem of determining the stability of a feedback system in the presence of perturbation is considered. A necessary and sufficient condition under which the perturbed system remains stable is obtained. This condition is very general. In particular, it does not require the perturbed plant to have the same number of poles as the nominal plant. View full abstract»

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  • Coprime fraction computation of 2-D rational matrices

    Publication Year: 1987 , Page(s): 333 - 336
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (424 KB)  

    This note presents a numerical method of computing a coprime fraction of a two-dimensional (2-D) rational matrix, not necessarily proper. It is achieved by searching the primary linearly dependent rows, in order from top to bottom, of the two generalized resultants. The procedure can be extended to the three- or higher dimensional case and the result can also be used to compute the greatest common divisor (GCD) of 2-D polynomial matrices without employing primitive factorizations which does not exist in the three- or higher dimensional case. View full abstract»

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  • Tuning of multivariable PI-controllers for unknown delay-differential systems

    Publication Year: 1987 , Page(s): 364 - 368
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB)  

    A design method for tuning of multivariable PI-controllers for possibly unknown linear time-invariant delay-differential systems is presented. The plant is assumed to be stable with input and output delays and subject to step disturbances. The multivariable PI-controller may be tuned with the aid of open-loop step responses. The stability and robustness of the control law is discussed and an example is given to show the applicability of the controller. View full abstract»

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  • Matrix partial fraction expansions of rational matrices

    Publication Year: 1987 , Page(s): 330 - 333
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (272 KB)  

    A general and rigorous derivation is made of a new formula, established recently in the literature, for matrix partial fraction expansion of a rational matrix. The procedure, by use of a minimal Jordan realization of the rational matrix, provides as a byproduct, general expressions for residue matrices in terms of products of columns of the output matrix and rows of the input matrix of the realization. View full abstract»

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  • A new computer graphics approach to parameter space design of control systems

    Publication Year: 1987 , Page(s): 294 - 302
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (912 KB)  

    This paper presents a new approach to parameter space design of linear multivariable control systems. The complete solution of a pole region assignment problem for single-input systems is obtained as an admissible region in the n -dimensional parameter space of state feedback gains. We develop a new modeling technique for these admissible parameter space regions which is superior to previous ones because it permits unambiguous and efficient graphical display of slices in 2D and 3D subspaces. In an interactive computer graphics implementation, this method provides an environment where the influence of stability, performance, robustness, integrity, and control constraints on design parameters can be directly visualized and complex tradeoffs are resolved in an interactive way. By judicious combination of overlays, color, and/ or animation, admissible ranges of up to five or six design parameters can be displayed simultaneously. A sequential decomposition technique which selects slices for full parameter space design of lower dimensional subsystems such that the remaining eigenvalues are invariant is used for systems of arbitrarily high order. Parameter space design of unity rank feedback for multiinput systems is done in exactly the same fashion, while systematic sequential design of full rank feedback is achieved as the sum of dyadic stages to which the single-input modeling techniques apply. Examples are given for all presented methods to show the flexibility and potential as a computer-aided control system design framework with a novel integration of computer graphics technology. View full abstract»

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  • On the parameters estimation of continuous-time ARMA processes from noisy observations

    Publication Year: 1987 , Page(s): 361 - 364
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (416 KB)  

    Recently, an iterative algorithm has been presented for estimating the parameters of partially observed continuous-time processes [1]. In this note we concentrate on continuous-time ARMA processes observed in white noise. A maximum a-posteriori (MAP) estimator is defined for the trajectory of the parameters' random process. This approach enables the MAP estimation of randomly slowly varying parameters, and extends the conventional treatment of time-invariant parameters. The iterative algorithm derived for the MAP estimation, increases the posterior probability of the parameters in each iteration, and converges to a stationary point of the posterior probability functional. Each iteration involves a standard linear smoother followed by a finite-dimensional linear system, and thus is easily implemented. View full abstract»

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  • Vibrational stabilization of a chemical reactor: An experimental study

    Publication Year: 1987 , Page(s): 348 - 352
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (576 KB)  

    Vibrational control is a method for modification of dynamic properties of linear and nonlinear systems by introduction of fast, zero-average oscillations in a system's parameters. It has been previously shown that forced oscillations introduced in the reactant flow rates to a continuous stirred tank reactor (CSTR) cause a modification of the S - shaped steady-state curve. In the present note experimental evidence is given to show that this modification leads to the operation the CSTR at an asymptotically stable periodic regime located near an unstable steady-state of the reactor system having fixed flow rates. For a given average stabilized state, such a stabilizing mechanism results in a higher production rate or lower energy expenditure compared to a steady operation with shifted input conditions. View full abstract»

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  • Command and control (C2) theory: A challenge to control science

    Publication Year: 1987 , Page(s): 286 - 293
    Cited by:  Papers (39)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1096 KB)  

    The basic premise of this perspectives paper is that the field of military command-and-control (C2) systems offers challenging basic research opportunities to researchers in the conlrol sciences and systems engineering disciplines, in point of fact, the analysis and design of complex, survivable, and responsive C2 systems requires novel advances in the area of distributed dynamic decision-making under uncertainty. Advances are also needed in systems engineering tools for describing, decomposing, and analyzing such systems. As a consequence, control scientists and engineers are uniquely- qualified to extend their technologies to meet the multidisciplinary challenges posed by C2 systems, to advance the state of the art in the development of a relevant C2 theory, and to contribute to the development of future military C2 systems that must meet stringent performance, survivability, and responsiveness specifications. The author strongly believes that the methodological, theoretical, algorithmic, and architectural questions which arise in the context of military C2 systems are generic and quite similar to those needed to improve the reliable performance of many other civilian C2 systems, such as air traffic control, automated transportation systems, manufacturing systems, nuclear reactor complexes, etc. All such military and civilian C2 systems are characterized by a high degree of complexity, a generic distribution of the decision-making process among several decision-making "agents," the need for reliable operation in the presence of multiple failures, and the inevitable interaction of humans with computer-based decision support systems and decision aids; moreover, they require the development of novel organizational forms and system architectures which provide for the harmonious interface of Ihe mission objectives associated with the C2 process and the physical hardware, such as sensors, communications, devices, computer hardware and software, and effectors-weapons or machines-which implement the overall command, control, and communications (C3) system whose purpose is to support the global C2 decision process. Military C2 systems provide one particular focus for the development of a whole new class of control/estimation/decision technologies-- technol- ogies which share the intellectual roots of current research in the control sciences, but which can grow and blossom into methods applicable to a very large variety of civilian complex systems. In addition, they exemplify the kind of growing complexity that systems scientists and engineers must continually face and find ways of managing. These military C2 processes and C3 systems provide the most stringent performance requirements, exhibit a clear-cut need for quantification of their measures of performance (MOP's) and measures of effectiveness (MOE's), and require novel distributed architectures and organizational forms. The discussion will undoubtedly reflect the personal bias of the author who has studied and researched military C3 systems over the past decade, and whose central thesis is that quantitative methodologies will provide a significant impact in performance improvements in these complex systems. The challenge is to develop the required theoretical and algorithmic tools to allow for systematic analyses and designs in future endeavors. View full abstract»

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  • FIR filters and recursive forms for continuous time-invariant state-space models

    Publication Year: 1987 , Page(s): 352 - 356
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (488 KB)  

    An FIR (finite impulse response) filter and an FIR smoother are introduced for continuous time-invariant state-space models. It is shown in this note that finite impulse responses of the FIR filter and smoother can be easily determined by solving a simple Riccati-type matrix differential equation on a finite interval. Especially for systems with stationary processes, finite impulse responses of the FIR filter and smoother become time-invariant and can be computed from simpler equations. For fast computational purposes, recursive forms of the FIR filter and smoother are derived by using adjoint variables. In this case all gains for recursive forms are shown to be constant. View full abstract»

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  • l^{1} -optimal feedback controllers for MIMO discrete-time systems

    Publication Year: 1987 , Page(s): 314 - 322
    Cited by:  Papers (40)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (744 KB)  

    The problem considered in this paper is the design of a closed-loop system consisting of a MIMO discrete-time plant and compensator in such a way that the system is internally stable and optimally tracks all persistent bounded inputs. The solution consists of two parts: first the calculation of the minimum value of the performance index (a weighted transfer function), which is done by solving a linear programming problem; and second, construction of the optimal transfer function by solving a set of linear equations. It is shown that, in general, the discrete-time problem will have a rational solution and thus appears to be of considerable practical significance. View full abstract»

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  • Families of linear-quadratic problems: Continuity properties

    Publication Year: 1987 , Page(s): 323 - 329
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (768 KB)  

    In this paper we investigate for given one-parameter families of linear time-invariant finite-dimensional systems the parameter dependence of the linear-quadratic optimal cost, optimal control inputs, optimal state-trajectories, and optimal outputs. It is shown that results that have been obtained in the past in the context of the problem of cheap control can in fact be generalized to a much broader class of parameter-dependent cost-functionals, including cost functionals in which for every parameter value the weighting matrix of the control inputs is singular. Essentially, only two assumptions on the parameter dependence of the cost-functionals are required in order to have continuity of the optimal cost and optimal control inputs with respect to the underlying parameter. One assumption is concerned with the continuity of the weighting matrices with respect to this parameter, the other with the monotonicy of the weighting matrices with respect to the parameter. Instrumental in our development is a characterization of the linear-quadratic optimal cost in terms of the so-called dissipation inequality. The results obtained are applied to the problem of cheap control and to a problem of priority control. The latter provides an example of a family of quadratic cosl-functionals with a polynomial parameter dependence. View full abstract»

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  • On the bounds for the roots of a polynomial

    Publication Year: 1987 , Page(s): 336 - 337
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    Some new sufficient conditions are presented which give bounds for the absolute values of the roots of a polynomial. These results extend certain earlier stability tests for linear discrete systems. View full abstract»

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  • Challenges to control: A collective view--Report of the workshop held at the University of Santa Clara on September 18-19, 1986

    Publication Year: 1987 , Page(s): 275 - 285
    Cited by:  Papers (18)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1552 KB)  

    During the last seven years, while structural changes have been taking place in the industrial sector of the U.S. and questions of technological leadership and technology transfer have been debated widely, new areas for research have been developing. This led the leadership of the IEEE Control Systems Society to recommend that a workshop be organized to assess the state of the art of the field and outline directions of research. An Organizing Committee, consisting of D. D. Siljak (Chairman), G. F. Franklin, A. H. Levis, and W. R. Perkins, submitted a proposal to the Systems Theory and Operations Research Program of the National Science Foundation to hold such a workshop at the University of Santa Clara, in Santa Clara, CA, on September 18-19, 1986. As part of the proposal effort, a Steering Committee was constituted to assist the organizers in selecting workshop participants and to carry out the preparalory work for the meeting. The twelve-member Steering Committee consisted of the four organizers and eight other individuals: R. W. Brockett, E. J. Davison, Y.-C. Ho, P. Kokotovic, A. J. Laub, S. 1. Marcus, W. F. Powers, and S. S. Sastry. In early 1986, the organizers issued an open call for participation in the workshop that was published in the April issue of the IEEE CONTROL SYSTEMS MAGAZINE. in addition, more than 150 letters were sent to leaders in the field, inviting them to apply for participation in the workshop. The Steering Committee was also asked to identify individuals who could provide unique perspectives. The cut-off date for applications, that included a statement of proposed contribution, was May 31. In June, during the 1986 American Control Conference, the Steering Committee met for many hours to select the participants from the many applicants and to decide on the final structure of the program. One of the decisions was to invite all the Presidential Young Investigator awardees who had applied, another was to limit the total number of participants to fifty. In addition to the Steering Committee, the following persons attended and contributed to the deliberations: K. J. Astrom, M. Athans, D. Auslander, J. S. Baras, T. Basar, G. Blankenship, S. P. Boyd, A. E. Bryson, Jr., J. Burns, J. Cassidy, J. B. Cruz, D. F. Delchamps, C. A. Desoer, R. F. - Drenick, T. Edgar, J. S. Freudenberg, D. Gangsaas, J. Grizzle, A. H. Haddad, W. E. Hopkins, Jr., M. Ilí-Spong, P. loannou, T. L. Johnson, T. Kailath, A. J. Krener, R. E. Larson, W. S. Levine, J. L. Melsa, J. M. Mendel, G. Meyer, J. B. Pearson, H. E. Rauch, G. N. Saridis, J. L. Speyer, J. N. Tsitsiklis, P. Varaiya, G. C. Verghese, M. Vidyasagar, A. S. Willsky, and M. Wonham. The National Science Foundation was represented by Dr. M. P. Polis, Program Director of the Systems Theory and Operations Research Program, and by Dr. G. Hazelrig, Acting Program Director of the Instrumentation, Sensing, and Measurement Systems Program. The workshop was organized into plenary sessions and breakout sessions, during which Working Groups discussed and wrote the material that forms the basis of this report. Seven keynote talks addressed the main themes of the workshop: accomplishments in the past twenty five years and definition of important current and future research problems drawn from the needs of the industrial and service sectors of the economy. The Working Groups were structured so that, while discussions could take place with few constraints, written materials could be produced by the end of each session. To that effect, each group had one or two persons designated as recorders, with the primary responsibility of keeping notes during the discussion and assisting the group leaders in preparing the Working Group draft reports. In order to provide some focus in the deliberations of the Working Groups,eight persons were asked to prepare position statements based on their own perspectives. Seven of these position papers are being published concurrently in the April 1987 View full abstract»

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  • A counterexample for two conjectures about stability

    Publication Year: 1987 , Page(s): 340 - 342
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB)  

    One measure of the stability of a matrix A is the distance to the nearest unstable matrix B . Recently Van Loan presented an algorithm to compute B which depended on a conjecture about the location of its eigenvalues. We provide a counterexample to this conjecture which shows that the algorithm may overestimate the distance to B by an arbitrary amount. The same counterexample invalidates another conjecture and algorithm of the author. View full abstract»

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  • Parametric models of linear multivariable systems for adaptive control

    Publication Year: 1987 , Page(s): 303 - 313
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (944 KB)  

    This paper presents a parametrization method for direct adaptive control of linear multivariable systems with strictly proper discrete-time or continuous-time transfer functions. The necessary a priori information is shown to be a diagonal matrix with the noninvertible zeros of the Smith form and appropriate polynomial degrees. View full abstract»

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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