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Automatic Control, IEEE Transactions on

Issue 12 • Date Dec. 2001

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Displaying Results 1 - 25 of 38
  • Comments on "Output feedback stabilization for uncertain systems: constrained Riccati approach"

    Publication Year: 2001
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (58 KB) |  | HTML iconHTML  

    For original paper, by Cheng, see ibid., vol.43, p.81-4 (1998). In that paper, a sufficient condition for the static output feedback stabilization of uncertain systems with mismatched uncertainties has been derived under the assumption that rank(B)/spl les/rank(C) where B and C are the input matrix and the output matrix respectively. In this note, we show that the sufficient condition of the original paper is not solvable if rank(B) View full abstract»

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  • Comments on "Output feedback stabilization for uncertain systems: constrained Riccati approach"

    Publication Year: 2001
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (45 KB) |  | HTML iconHTML  

    For original paper, by Cheng, see ibid., vol.43, p.81-4 (1998). In the above paper, the constrained Riccati problem (CRP) has been proposed to deal with mismatched uncertainty by extending the concept of the constrained Lyapunov problem. In this note, we show the solvability condition for the CRP only gives a solution for the class of square systems not for the nonsquare systems. View full abstract»

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  • Fixed interval smoothing for state-space models [Book Review]

    Publication Year: 2001 , Page(s): 2046 - 2047
    Save to Project icon | Request Permissions | PDF file iconPDF (26 KB) |  | HTML iconHTML  
    Freely Available from IEEE
  • Author index

    Publication Year: 2001 , Page(s): 2049 - 2057
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    Freely Available from IEEE
  • Subject index

    Publication Year: 2001 , Page(s): 2057 - 2080
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    Freely Available from IEEE
  • Stabilization and controllability for the transmission wave equation

    Publication Year: 2001 , Page(s): 1900 - 1907
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (282 KB) |  | HTML iconHTML  

    We address the problem of control of the transmission wave equation. In particular, we consider the case where, due to total internal reflection of waves at the interface, the system may not be controlled from exterior boundaries. We show that such a system can be controlled by introducing both boundary control along the exterior boundary and distributed control near the transmission boundary and give a physical explanation why the additional control near the transmission boundary might be needed for some domains View full abstract»

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  • Shape-based optimal estimation and design of curve evolution processes with application to plasma etching

    Publication Year: 2001 , Page(s): 1862 - 1873
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (303 KB) |  | HTML iconHTML  

    Considers the problem of determining a finite number of discrete parameters appearing in a nonlinear partial differential equation describing a curve evolution process. The method is applied to the plasma etching of thin films for semiconductor manufacturing. Results are obtained within the mathematical framework of level set methods. Here, the evolution of the curve under study is captured through the evolution of a level set function. The underlying physics of the process are completely contained in a scalar function called the speed function. The degree of difficulty of treating the evolution equation depends on the functional dependencies of the speed function. The paper presents optimal estimation and design techniques based on analytical gradient computations for a class of position and orientation dependent speed functions. The technique is demonstrated on a plasma etching model taken from the literature. Only simulation results are presented, but the model under study has been shown to reproduce experimental data with reasonable accuracy. In the estimation problem, parameters in the model are fit to best match the feature shape measured in experiments. In the optimal design problem, parameter values are selected to most closely attain a desired feature shape View full abstract»

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  • Boundary control of an unstable heat equation via measurement of domain-averaged temperature

    Publication Year: 2001 , Page(s): 2022 - 2028
    Cited by:  Papers (45)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (256 KB) |  | HTML iconHTML  

    In this note, a feedback boundary controller for an unstable heat equation is designed. The equation can be viewed as a model of a thin rod with not only the heat loss to a surrounding medium (stabilizing) but also the heat generation inside the rod (destabilizing). The heat generation adds a destabilizing linear term on the right-hand side of the equation. The boundary control law designed is in the form of an integral operator with a known, continuous kernel function but can be interpreted as a backstepping control law. This interpretation provides a Lyapunov function for proving stability of the system. The control is applied by insulating one end of the rod and applying either Dirichlet or Neumann boundary actuation on the other View full abstract»

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  • On the consistency between an LFT described model set and frequency domain data

    Publication Year: 2001 , Page(s): 2001 - 2007
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (252 KB) |  | HTML iconHTML  

    The main objective of this technical note is to derive a simple necessary and sufficient condition for a linear fractional transformation (LFT) perturbed model set being consistent with frequency domain plant input-output data. Only discrete-time models and unstructured modeling errors are dealt with. Compared with the available results in which the eigenvalues of a matrix are involved, this condition is related only to the Euclidean norms of two vectors. Moreover, these vectors linearly depend on measurement errors. Some of its applications to model set validation have been briefly discussed. Based on this condition, an almost analytic solution has been established for model set validation under a deterministic framework when the measurement errors are energy bounded. Numerical simulations show that this consistency condition can lead to a significant computation cost reduction View full abstract»

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  • A robust state observer scheme

    Publication Year: 2001 , Page(s): 1958 - 1963
    Cited by:  Papers (33)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (163 KB) |  | HTML iconHTML  

    This note proposes a new approach to robust state observer construction. The scheme is derived by including an extra term and adopting the Lyapunov stability theorem, and requires the solution of an algebraic Riccati equation. The scheme is implemented in a gas-fired furnace system example. Satisfactory results have been obtained, though in general special attention need be paid to some numerical issues in implementing the scheme View full abstract»

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  • A general invariance principle for nonlinear time-varying systems and its applications

    Publication Year: 2001 , Page(s): 1989 - 1993
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (148 KB) |  | HTML iconHTML  

    A general invariance principle, from the output-to-state point of view, is proposed for the dynamical analysis of nonlinear time-varying systems. This is achieved by the construction of a simple and intuitive criterion using integral inequality of the output function and modified detectability conditions. The proposed scheme can be viewed as an extension of the integral invariance principle (C.I. Byrnes and C.F. Martin, 1995) for time-invariant systems to time-varying systems. Such extension is nontrivial and can be used in various research areas such as adaptive control, tracking control and the control of driftless systems. An application to global tracking control of four-wheeled mobile robots is given to demonstrate the feasibility and validity of the proposed approach View full abstract»

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  • A case study for the open question: disturbance decoupling problem for singular systems by output feedback

    Publication Year: 2001 , Page(s): 1924 - 1930
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (224 KB)  

    We study the disturbance decoupling problem for singular systems Ex˙=Ax+Bu+Gd, y=Cx, z=Hx with left invertibility. We give necessary and sufficient conditions for the existence of a solution to the disturbance decoupling problem with or without stability by output feedback that also makes the resulting closed-loop system regular and/or of index at most one. All results are proved based on a condensed form that can be computed using orthogonal transformations, i.e., can be computed in a numerically stable way View full abstract»

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  • On the convergence rate of ordinal comparisons of random variables

    Publication Year: 2001 , Page(s): 1950 - 1954
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (147 KB) |  | HTML iconHTML  

    The asymptotic exponential convergence rate of ordinal comparisons follows from well-known results in large deviations theory, where the critical condition is the existence of a finite moment generating function. In this note, we show that this is both a necessary and sufficient condition, and also show how one can recover the exponential convergence rate in cases where the moment generating function is not finite. In particular, by working with appropriately truncated versions of the original random variables, the exponential convergence rate can be recovered View full abstract»

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  • Continuous-time analysis, eigenstructure assignment, and H2 synthesis with enhanced linear matrix inequalities (LMI) characterizations

    Publication Year: 2001 , Page(s): 1941 - 1946
    Cited by:  Papers (126)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (163 KB) |  | HTML iconHTML  

    This note describes a new framework for the analysis and synthesis of control systems, which constitutes a genuine continuous-time extension of results that are only available in discrete time. In contrast to earlier results the proposed methods involve a specific transformation on the Lyapunov variables and a reciprocal variant of the projection lemma, in addition to the classical linearizing transformations on the controller data. For a wide range of problems including robust analysis and synthesis, multichannel H2 stateand output-feedback syntheses, the approach leads to potentially less conservative linear matrix inequality (LMI) characterizations. This comes from the fact that the technical restriction of using a single Lyapunov function is to some extent ruled out in this new approach. Moreover, the approach offers new potentials for problems that cannot be handled using earlier techniques. An important instance is the eigenstructure assignment problem blended with Lyapunov-type constraints which is given a simple and tractable formulation View full abstract»

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  • New bounded real lemma representations for time-delay systems and their applications

    Publication Year: 2001 , Page(s): 1973 - 1979
    Cited by:  Papers (48)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (237 KB) |  | HTML iconHTML  

    New delay-dependent/delay-independent bounded real criteria are derived for linear continuous-time systems with delay in the dynamics and in the objective function. A sufficient condition for the system to possess a H-norm that is less than a prescribed level, is given in terms of a linear matrix inequality (LMI). The proposed criteria are less conservative than other existing criteria since they are based on an augmented model that is equivalent to the original system and since they require bounds for fewer terms. We apply the new bounded real criteria to state-feedback H control. The advantage of the new criteria is demonstrated by four examples. The first two compare our results with those obtained in the literature for the bounded real lemma and the other two examples treat the state-feedback control problem and compare our result with recently published designs View full abstract»

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  • A matrix method for determining the imaginary axis eigenvalues of a delay system

    Publication Year: 2001 , Page(s): 2008 - 2012
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (199 KB) |  | HTML iconHTML  

    The author considers autonomous neutral or retarded matrix delay differential systems. The imaginary axis eigenvalues of such a system are shown to be contained in the set of generalized eigenvalues of an associated matrix pair. If the system is not a singular neutral system, one can replace generalized eigenvalues by the eigenvalues of a single matrix. We also show in both the neutral and retarded cases that system pure imaginary eigenvalues are limited to the values at which an associated second degree matrix polynomial becomes singular. Associated system eigenvectors are also eigenvectors of this matrix polynomial. Examples are given in which the matrix, the matrix pair, and the matrix polynomial are used for stability analysis View full abstract»

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  • Nonlinear adaptive controller with integral action

    Publication Year: 2001 , Page(s): 2035 - 2037
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (98 KB) |  | HTML iconHTML  

    This note reveals a new significant property of the adaptive controller design technique proposed by Krstic, Kanellakopoulos and Kokotovic (1994). Namely, it is shown that with the use of special plant model parametrization the standard backstepping design results in an adaptive controller with integral action. The latter means that the controller completely rejects constant input disturbances. It is shown that the revealed property can be extended to nonlinear and nonadaptive cases View full abstract»

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  • Adaptive control of triangular systems with nonlinear parameterization

    Publication Year: 2001 , Page(s): 1963 - 1968
    Cited by:  Papers (18)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (214 KB) |  | HTML iconHTML  

    The paper deals with adaptive control of uncertain nonlinear triangular systems whose uncertainty is characterized by nonlinear parameterization of unknown constant vectors. Robust adaptive control techniques are incorporated in the backstepping control design with flat zones to tackle the nonlinear parameterization together with a novel smooth projection algorithm for parameter estimation. The proposed algorithm guarantees the global boundedness of all the variables and the convergence of the tracking error to any prespecified small limit View full abstract»

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  • Robust stabilization of large space structures via displacement feedback

    Publication Year: 2001 , Page(s): 1993 - 1996
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (119 KB) |  | HTML iconHTML  

    It has been known that static velocity and displacement feedback with collocated sensors and actuators can stabilize large space structures robustly against "any" uncertainty in mass, damping, and stiffness, independently of the number of flexible modes. The authors present dynamic displacement feedback which can achieve such robust stabilization. The proposed control law can be implemented in a decentralized scheme straightforwardly View full abstract»

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  • Asymptotic variance expressions for estimated frequency functions

    Publication Year: 2001 , Page(s): 1887 - 1899
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (360 KB) |  | HTML iconHTML  

    Expressions for the variance of an estimated frequency function are necessary for many issues in model validation and experiment design. A general result is that a simple expression for this variance can be obtained asymptotically as the model order tends to infinity. This expression shows that the variance is inversely proportional to the signal-to-noise ratio frequency by frequency. Still, for low order models the actual variance may be quite different. We derive an exact expression for the variance, which is not asymptotic in the model order. This expression applies to a restricted class of models: AR-models, as well as fixed pole models with a polynomial noise model. It brings out the character of the simple approximation and the convergence rate to the limit as the model order increases. It also provides nonasymptotic lower bounds for the general case. The calculations are illustrated by numerical examples View full abstract»

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  • Stability properties of equilibria of classes of cooperative systems

    Publication Year: 2001 , Page(s): 1996 - 2001
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (208 KB) |  | HTML iconHTML  

    This note deals with the constant control problem for homogeneous cooperative and irreducible systems. These systems serve as models for positive systems. A necessary and sufficient condition for global asymptotic stability of the zero solution of this class of systems is known. Adding a constant control allows to shift the equilibrium point from zero to a point in the first orthant. We prove that for every nontrivial nonnegative control vector a unique nontrivial equilibrium point is achieved which is globally asymptotically stable if the zero solution of the uncontrolled system is globally asymptotically stable. In addition a converse result is provided. Finally a stability result for a particular class of Kolmogorov systems is established. We compare our main results to those in the literature View full abstract»

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  • An approximation method for controlled discrete jump processes under partial observations

    Publication Year: 2001 , Page(s): 1850 - 1861
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (349 KB) |  | HTML iconHTML  

    The paper is concerned with control and filtering of a discrete jump Markov process when only the total number of jumps is observed. A partially observable control problem is considered and equivalence between this problem and the separated one is proved. A technique to approximate the value function, under some suitable assumptions, is presented View full abstract»

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  • Robust H control of discrete-time Markovian jump linear systems with mode-dependent time-delays

    Publication Year: 2001 , Page(s): 1918 - 1924
    Cited by:  Papers (93)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (260 KB) |  | HTML iconHTML  

    Considers the class of discrete-time Markovian jump linear system with norm-bounded uncertainties and time-delay, which is dependent on the system mode. Linear matrix inequality (LMI)-based sufficient conditions for the stability, stabilization and H control are developed. A numerical example is worked out to show the usefulness of the theoretical results View full abstract»

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  • Banded matrix fraction representation of triangular input normal pairs

    Publication Year: 2001 , Page(s): 2018 - 2022
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (192 KB) |  | HTML iconHTML  

    An input pair (A, B) is triangular input normal if and only if A is triangular and AA* + BB* = In, where In is the identity matrix. Input normal pairs generate an orthonormal basis for the impulse response. Every input pair may be transformed to a triangular input normal pair. A new system representation is given: (A, B) is triangular normal and A is a matrix fraction, A = M-1 N, where M and N are triangular matrices of low bandwidth. For single input pairs, M and N are bidiagonal and an explicit parameterization is given in terms of the eigenvalues of A. This band fraction structure allows for fast updates of state space systems and fast system identification. When A has only real eigenvalues, one state advance requires 3n multiplications for the single input case View full abstract»

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  • Stabilization of discrete time linear systems by static output feedback

    Publication Year: 2001 , Page(s): 1954 - 1958
    Cited by:  Papers (22)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (121 KB) |  | HTML iconHTML  

    This note proposes a systematic approach for the static output feedback control design for discrete time linear systems. It is shown that if the open loop system satisfies some particular structural conditions, a static output feedback gain can be calculated easily, using a formula only involving the original system matrices. Among the conditions the system has to satisfy, the stronger relies on a minimum phase argument. Square and nonsquare systems are considered 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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Editor-in-Chief
P. J. Antsaklis
Dept. Electrical Engineering
University of Notre Dame