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Automatic Control, IEEE Transactions on

Issue 2 • Date Feb. 2001

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Displaying Results 1 - 22 of 22
  • Introduction to discrete event systems [Book Review]

    Publication Year: 2001 , Page(s): 353 - 354
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    Freely Available from IEEE
  • Sampling zeros and the Euler-Frobenius polynomials

    Publication Year: 2001 , Page(s): 340 - 343
    Cited by:  Papers (18)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (132 KB)  

    We show that the zeros of sampled-data systems resulting from rapid sampling of continuous-time systems preceded by a zero-order hold (ZOH) are the roots of the Euler-Frobenius polynomials. Using known properties of these polynomials, we prove two conjectures of Hagiwara et al. (1993), the first of which concerns the simplicity, negative realness, and interlacing properties of the sampling zeros of ZOH- and first-order hold (FOH-) sampled systems. To prove the second conjecture, we show that in the fast sampling limit, and as the continuous-time relative degree increases, the largest sampling zero for FOH-sampled systems approaches 1/e, where e is the base of the natural logarithm View full abstract»

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  • Robust nonfragile Kalman filtering for uncertain linear systems with estimator gain uncertainty

    Publication Year: 2001 , Page(s): 343 - 348
    Cited by:  Papers (46)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (212 KB)  

    The note is concerned with the problem of a robust nonfragile Kalman filter design for a class of uncertain linear systems with norm-bounded uncertainties. The designed state estimator can tolerate multiplicative uncertainties in the state estimator gain matrix. The robust nonfragile state estimator designs are given in terms of solutions to algebraic Riccati equations. The designs guarantee known upper bounds on the steady-state error covariance. A numerical example is given to illustrate the results View full abstract»

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  • On system identification of complex systems from finite data

    Publication Year: 2001 , Page(s): 235 - 257
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (568 KB)  

    We introduce a new principle for identification based on choosing a model from the model-parameterization, which best approximates the unknown real system belonging to a more complex space of systems that do not lend themselves to a finite-parameterization. The principle is particularly effective for robust control as it leads to a precise notion of parametric and nonparametric error, and the identification problem can be equivalently perceived as that of robust convergence of the parameters in the face of unmodeled errors. The main difficulty in its application stems from the interplay of noise and unmodeled dynamics and requires developing novel two-step algorithms that amount to annihilation of the unmodeled error followed by averaging out the noise. The paper establishes: robust convergence for a large class of systems, topologies, and unmodeled errors; sample path based finite-time polynomial rate of convergence; and annihilation-correlation algorithms for linearly parameterized model structures View full abstract»

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  • On reachability and stabilization of switched linear systems

    Publication Year: 2001 , Page(s): 291 - 295
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (188 KB)  

    Reachability and stabilization issues for switched linear control systems are addressed. A necessary and a sufficient condition are presented for reachability. Under mild assumptions, we prove that the switched linear control systems are stabilizable. In addition, we show that an element-driven switching stabilization strategy can be explicitly constructed View full abstract»

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  • On an output feedback finite-time stabilization problem

    Publication Year: 2001 , Page(s): 305 - 309
    Cited by:  Papers (126)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (188 KB)  

    Studies the problem of finite-time output feedback stabilization for the double integrator system. A class of output feedback controllers that can achieve global finite-time stability for the double integrator system are constructed based on a “finite-time separation principle.” Furthermore, it is shown that the closed-loop system resulting from our control law can maintain its local finite-time stability regardless of some nonlinear perturbations. Thus, our control law actually applies to a large class of nonlinear second order systems View full abstract»

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  • Control of singularly perturbed hybrid stochastic systems

    Publication Year: 2001 , Page(s): 179 - 190
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB)  

    We study a class of optimal stochastic control problems involving two different time scales. The fast mode of the system is represented by deterministic state equations whereas the slow mode of the system corresponds to a jump disturbance process. Under a fundamental “ergodicity” property for a class of “infinitesimal control systems” associated with the fast mode, we show that there exists a limit problem which provides a good approximation to the optimal control of the perturbed system. Both the finite- and infinite-discounted horizon cases are considered. We show how an approximate optimal control law can be constructed from the solution of the limit control problem. In the particular case where the infinitesimal control systems possess the so-called turnpike property, i.e., characterized by the existence of global attractors, the limit control problem can be given an interpretation related to a decomposition approach View full abstract»

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  • On the complete controllability indexes assignment problem

    Publication Year: 2001 , Page(s): 348 - 352
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    New solvability conditions for the simultaneous assignment by static-state feedback of both the controllability indexes of (A, B) and the invariant factors of (sI-A, -B) are given. These conditions enhance the fact that this problem is a generalization of the control structure problem of Rosenbrock (1970) and of the controllability indexes assignment problem of Heymann (1981). The choice of a polynomial framework allows one to obtain simpler proofs of the results than those previously published View full abstract»

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  • Reliable decentralized integral-action controller design

    Publication Year: 2001 , Page(s): 296 - 301
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (260 KB)  

    Reliable stabilizing controller design with integral-action is considered for linear time-invariant, multi-input-multi-output decentralized systems with stable plants. Design methods are proposed to achieve reliable closed-loop stability with integral-action in each output channel for asymptotic tracking of step-input references applied at each input. The design approaches guarantee stability and integral-action in the active channels when all controllers are operational and when any of the controllers is set equal to zero due to failure View full abstract»

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  • H bounds for least-squares estimators

    Publication Year: 2001 , Page(s): 309 - 314
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (212 KB)  

    We obtain upper and lower bounds for the H norm of the Kalman filter and the recursive-least-squares (RLS) algorithm, with respect to prediction and filtered errors. These bounds can be used to study the robustness properties of such estimators. One main conclusion is that, unlike H-optimal estimators which do not allow for any amplification of the disturbances, the least-squares estimators do allow for such amplification. This fact can be especially pronounced in the prediction error case, whereas in the filtered error case the energy amplification is at most four. Moreover, it is shown that the H norm for RLS is data dependent, whereas for least-mean-squares (LMS) algorithms and normalized LMS, the H norm is simply unity View full abstract»

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  • Jump linear quadratic regulator with controlled jump rates

    Publication Year: 2001 , Page(s): 301 - 305
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (168 KB)  

    Deals with the class of continuous-time linear systems with Markovian jumps. We assume that jump rates are controlled. Our purpose is to study the jump linear quadratic (JLQ) regulator of the class of systems. The structure of the optimal controller is established. For a one-dimensional (1-D) system, an algorithm for solving the corresponding set of coupled Riccati equations of this optimal control problem is provided. Two numerical examples are given to show the usefulness of our results View full abstract»

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  • Singular sliding-mode control

    Publication Year: 2001 , Page(s): 276 - 285
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (360 KB)  

    Studies sliding-mode control where the usual regularity assumptions need not hold. In particular, we allow “singular submanifolds” near which the state trajectory cannot be steered toward the sliding surface. For nonlinear systems whose singular submanifold satisfies suitable transversality conditions, we identify a class of smooth output functions which can be asymptotically or approximately tracked using a globally defined discontinuous controller View full abstract»

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  • Limitations of a class of stabilization methods for delay systems

    Publication Year: 2001 , Page(s): 336 - 339
    Cited by:  Papers (31)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (132 KB)  

    We investigate limitations of certain stabilization methods for time-delay systems. The class of methods under consideration implements the control law through a Volterra integral equation of the second kind. Using as an example the pole placement approach of Manitius and Olbrot (1979), we illustrate how instability of the difference part of the control law leads to instability in the closed-loop system, in the case that implementation is done via numerical quadrature. The outcome of our analysis provides computable limitations to stability and a maximum allowable size of the (input) delay View full abstract»

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  • Simulation-based optimization of Markov reward processes

    Publication Year: 2001 , Page(s): 191 - 209
    Cited by:  Papers (77)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (496 KB)  

    This paper proposes a simulation-based algorithm for optimizing the average reward in a finite-state Markov reward process that depends on a set of parameters. As a special case, the method applies to Markov decision processes where optimization takes place within a parametrized set of policies. The algorithm relies on the regenerative structure of finite-state Markov processes, involves the simulation of a single sample path, and can be implemented online. A convergence result (with probability 1) is provided View full abstract»

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  • A general framework for deterministic service guarantees in telecommunication networks with variable length packets

    Publication Year: 2001 , Page(s): 210 - 221
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    By extending the recently developed filtering theory under the min-plus algebra to the max-plus algebra, we develop a general framework for providing deterministic quality-of-service guarantees in telecommunication networks with variable length packets. The traffic in such networks is modeled by marked point processes that consist of two sequences of variables: the arrival times and the packet lengths. By modifying Cruz's characterization for a counting process, we propose a traffic characterization, called g-regularity, to characterize a marked point process. Based on the traffic characterization, we introduce two basic network elements: traffic regulators that generate g-regular marked point processes; and g-servers that provides quality-of-service for marked point processes. As in the filtering theory under the min-plus algebra, network elements can be joined by concatenation, “filter bank summation”, and feedback to form a composite network element. We illustrate the use of the framework by various examples that include G/G/1 queues, VirtualClock, guaranteed rate servers in tandem, segmentation and reassembly, jitter control, dampers, and window flow control View full abstract»

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  • Convex and finite-dimensional conditions for controller synthesis with dynamic integral constraints

    Publication Year: 2001 , Page(s): 222 - 234
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (380 KB)  

    In this paper, the problem of synthesizing controllers when the allowable disturbances and the cost criterion are defined via a finite number of matrix valued dynamic integral constraints, is solved. This allows one to design optimal control systems for plants subject to fixed-input disturbances (such as steps, sinusoids, and periodic disturbances), disturbances of fixed and known spectrum, disturbances defined as the set of signals in the kernel of a given operator, and combinations thereof, to penalize particular frequency components of the error variables in the control design process, to penalize the maximum amplitude of an error variable, and to consider other general cost criteria in the optimization, and to solve a large class of robust control synthesis problems. Necessary and sufficient conditions for the general problem to have a solution are in terms of a computationally attractive, finite dimensional linear matrix inequality View full abstract»

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  • Identification of closed-loop linear systems via cyclic spectral analysis given noisy input-output time-domain data

    Publication Year: 2001 , Page(s): 258 - 275
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (648 KB)  

    The problem of closed-loop system identification given noisy time-domain input-output measurements is considered. It is assumed that the various disturbances affecting the system are zero-mean stationary whereas the closed-loop system operates under an external cyclostationary input which is not measured. Noisy measurements of the (direct) input and output of the plant are assumed to be available. The closed-loop system must be stable, but it is allowed to be unstable in open loop. No knowledge about the linear-feedback mechanism is assumed. Two identification algorithms are investigated using cyclic spectral analysis of noisy input-output data. For both approaches, the open-loop transfer function is first estimated using the cyclic spectrum and cyclic cross-spectrum of the input-output data. These transfer function estimates are then used as “data” for the proposed algorithms. Both classes of parameter estimators are shown to be weakly consistent in any stationary noise (both at input as well as output). Asymptotic performance analysis of the proposed parameter estimators is also provided. Computer simulation examples are presented in support of the proposed approaches View full abstract»

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  • Testing the rank of the Hankel covariance matrix: a statistical approach

    Publication Year: 2001 , Page(s): 331 - 336
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB)  

    The rank of the Hankel matrix, corresponding to a system transfer function, is equal to the order of its minimal state space realization. The computation of the rank of the Hankel matrix is complicated by the fact that its block elements are rarely given exactly but are estimated instead. We propose statistical tests to determine the rank of the Hankel matrix. We also provide a Monte Carlo study on the reliability of these tests compared to existing procedures View full abstract»

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  • Reduction of controller fragility by pole sensitivity minimization

    Publication Year: 2001 , Page(s): 320 - 325
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB)  

    Presents a method for the reduction of controller fragility. The method is based on the sensitivity of closed-loop poles to perturbations in the controller parameters. By means of a state space parameterization of the controller, the closed-loop pole sensitivity can be reduced. A controller fragility measure based on the closed-loop pole sensitivity is proposed. Conditions for the optimal state-space realization of the controller are presented, along with a numerical method for obtaining the solution View full abstract»

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  • Sequential identification and control for bounded-noise ARX systems

    Publication Year: 2001 , Page(s): 325 - 331
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (220 KB)  

    An optimal combination of sequential identification and control for a linear bounded-input bounded-noise discrete-time ARX plant is considered. Various configurations of identifying/controlling sequences are investigated in order to find an optimal tradeoff. The optimal identifying input sequence is determined by maximization of a given identification accuracy measure while the control input sequence is derived to assure a good tracking of the control system. A second-order model is taken for simulation and optimization View full abstract»

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  • On formal power series representations for uncertain systems

    Publication Year: 2001 , Page(s): 314 - 319
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (228 KB)  

    The concept of minimality as developed for uncertain and multidimensional systems represented by linear fractional transformations (LFTs) is related to realization theory results for formal power series. We discuss the relationship between the notions of minimality for LFT and series realizations, and present a method for obtaining one type of minimal realization from the opposing type. An extension of an existing minimality result for formal power series to the multi-input-multi-output (MIMO) case is also presented View full abstract»

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  • On computing normalized-coprime factorizations of general rational matrices

    Publication Year: 2001 , Page(s): 286 - 290
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB)  

    Presents a numerically reliable approach for computing the normalized-coprime factorization of an arbitrary (possibly improper) rational matrix. We consider both the cases in which the factorization is coprime and normalized with respect to either the left-half plane or the unit disk, corresponding to systems with continuous- or discrete-time evolutions. The proposed algorithm remedies the numerical drawbacks of alternative methods available thus far in the literature 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