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Automatic Control, IEEE Transactions on

Issue 6 • Date Jun 1992

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Displaying Results 1 - 25 of 33
  • A loop-shaping design procedure using H synthesis

    Publication Year: 1992 , Page(s): 759 - 769
    Cited by:  Papers (192)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (904 KB)  

    A design procedure is introduced which incorporates loop shaping methods to obtain performance/robust stability tradeoffs, and a particular H optimization problem to guarantee closed-loop stability and a level of robust stability at all frequencies. Theoretical justification of this technique is given, and the effect of loop shaping on closed-loop behavior is examined. The procedure is illustrated in a controller design for a flexible space platform View full abstract»

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  • Some generalized notions of observability

    Publication Year: 1992 , Page(s): 856 - 860
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    Generalized state-space systems are a more natural way of describing dynamical behavior than standard state-space systems. Such systems exhibit a much richer observability structure than standard state-space systems. Three notions of observability are defined for generalized state-space systems. In contrast to previous work, regularity is not assumed. Geometric characterization of each type of observability and matrix rank tests for each type of observability are derived View full abstract»

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  • L2-gain analysis of nonlinear systems and nonlinear state-feedback H control

    Publication Year: 1992 , Page(s): 770 - 784
    Cited by:  Papers (365)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1108 KB)  

    Previously obtained results on L2-gain analysis of smooth nonlinear systems are unified and extended using an approach based on Hamilton-Jacobi equations and inequalities, and their relation to invariant manifolds of an associated Hamiltonian vector field. On the basis of these results a nonlinear analog is obtained of the simplest part of a state-space approach to linear H control, namely the state feedback H optimal control problem. Furthermore, the relation with H control of the linearized system is dealt with View full abstract»

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  • When are the complex and the real stability radii equal?

    Publication Year: 1992 , Page(s): 880 - 883
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    Characterization of those real stable matrices for which the unstructured complex and real stability radii are equal is presented. Special cases of this equality are discussed. As application of this result, it is shown that, for 2×2 matrices with nonreal eigenvalues, neither the case of equality nor the case of strict inequality is generic View full abstract»

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  • Extreme point results for robust stabilization of interval plants with first-order compensators

    Publication Year: 1992 , Page(s): 707 - 714
    Cited by:  Papers (34)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (460 KB)  

    It has been shown previously that a first-order compensator robustly stabilizes an internal plant family if and only if it stabilizes all of the extreme plants. These extreme plants are obtained by considering all possible combinations for the extreme values of the numerator and denominator coefficients. In this work, the authors prove a stronger result, namely, that it is necessary and sufficient to stabilize only sixteen of the extreme plants. These sixteen plants are generated using the Kharitonov polynomials associated with the numerator and denominator. Furthermore, when additional information about the compensator is specified (sign of the gain and signs and relative magnitudes of the pole and zero), then, in some cases, it is necessary and sufficient to stabilize eight critical plants, while, in other cases, it is necessary and sufficient to stabilize twelve critical plants View full abstract»

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  • Geometric theory for the singular Roesser model

    Publication Year: 1992 , Page(s): 801 - 806
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (548 KB)  

    (A,E,B)-invariant and (E,A ,B)-invariant subspaces for the two-dimensional singular Roesser model are investigated. These subspaces are related to the existence of the solutions when the boundary conditions are in these subspaces. Also, the existence of a solution sequence in certain subspaces derived from the invariant subspaces is shown. The boundary conditions that appear in the solution when some semistates in the solution are restricted to zero are also investigated View full abstract»

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  • Design of observers for linear systems with unknown inputs

    Publication Year: 1992 , Page(s): 871 - 875
    Cited by:  Papers (125)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB)  

    With a straightforward treatment, a design of reduced-order observers is presented for linear systems with unknown inputs. The observers are derived with a physical meaning. Some explanations are given within the framework of descriptor system observer design principles. The conditions for the existence of the observers are presented. Some illustrative examples are included View full abstract»

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  • Game theory approach to optimal linear state estimation and its relation to the minimum H-norm estimation

    Publication Year: 1992 , Page(s): 828 - 831
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (356 KB)  

    A possible game theory approach to optimal state estimation is presented. It is found that in a certain differential game, the minimizer's policy is identical to the one obtained by optimal estimation in the minimum H-norm sense. This interpretation of H-optimal state estimation provides better insight into the mechanism of H-optimal filtering, especially in the case where the exogenous signals are not energy bounded View full abstract»

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  • On obtaining a realization of a polynomial matrix description of a system

    Publication Year: 1992 , Page(s): 852 - 855
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (380 KB)  

    The computation of a state-space realization of a linear dynamical system. starting from a polynomial matrix description of it, is addressed. Simple procedures are given for obtaining its dynamic matrix (possibly in some canonical or block-companion form) through unimodular transformations, starting from a square diagonal polynomial matrix, obtained as an intermediate step of the overall realization algorithm View full abstract»

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  • An H approach to feedback design with two objective functions

    Publication Year: 1992 , Page(s): 820 - 824
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB)  

    The problem of tightly bounding and shaping the frequency responses of two objective functions Ti(s)( i=1,2) associated with a closed-loop system is considered. It is proposed that an effective way of doing this is to minimize (or bound) the function max {||T1(s)|| , ||T2(s)||} subject to internal stability of the closed-loop system. The problem is formulated as an H control problem, and an iterative solution is given View full abstract»

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  • Identification with nonparametric uncertainty

    Publication Year: 1992 , Page(s): 715 - 728
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1200 KB)  

    An identification technique that is robust to nonparametric uncertainty (i.e. model mismatch) is presented. The identifier produces either a parameter set estimate or a frequency response set estimate. The estimates result from the inclusion of a model of the nonparametric uncertainty in the plant model. The frequency response set estimate is shown to always contain the frequency response of the plant as long as certain modeling conditions are met. This type of identifier would be useful in applications such as control where a property such as stability or performance level must be achieved in the face of low-order modeling and its associated nonparametric uncertainty View full abstract»

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  • A new version of the Chang transformation

    Publication Year: 1992 , Page(s): 800 - 801
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (160 KB)  

    A new decoupling transformation is proposed for singularly perturbed linear systems. This transformation has the advantage over the previous one in that, in order to find such a transformation, only one algorithm is required, and the computation can be done in parallel, because the transformation matrices are obtained from two independent equations that are identical in form View full abstract»

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  • A variable structure control with simple adaptation laws for upper bounds on the norm of the uncertainties

    Publication Year: 1992 , Page(s): 860 - 865
    Cited by:  Papers (62)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB)  

    In deterministic design of feedback controllers for uncertain dynamical systems, upper bounds on the norm of the uncertainties are an important clue to guarantee the stability of the closed-loop system. Sometimes, however these upper bounds may not be easily obtained because of the complexity of structure of the uncertainties. Simple adaptation laws for upper bounds on the norm of the uncertainties are proposed, and these adaptive upper bounds are used to design a variable-structure control system that guarantees the asymptotic stability of uncertain dynamical systems View full abstract»

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  • The symmetric Rouche's form for robustness

    Publication Year: 1992 , Page(s): 810 - 812
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (296 KB)  

    The objective of this work is to bring to control literature the strengthened and symmetric version of the classical Rouche's form. The author discusses the need for Rouche's form as a tool for the analysis of linear time-invariant control systems. A robustness criterion is given, and its corresponding geometrical interpretation is obtained. A simplified implementation of the symmetric form is obtained, and its relation to passivity is highlighted. An application to time delay systems is given View full abstract»

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  • A simple method for deriving J-spectral factors

    Publication Year: 1992 , Page(s): 891 - 895
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (400 KB)  

    A simple method is presented for deriving the J-spectral factor of a transfer function matrix explicitly in terms of the parameters of this matrix. This method provides closed-form expressions for the J-spectral factor and its inverse which only require a solution of a single linear Sylvester equation. This method can be easily applied in the solution of the H-optimal regulation problem, and it provides useful geometric insight into the structure of the optimal regulator return difference matrix View full abstract»

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  • A simple observer for nonlinear systems applications to bioreactors

    Publication Year: 1992 , Page(s): 875 - 880
    Cited by:  Papers (366)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB)  

    An observer for nonlinear systems is constructed under rather general technical assumptions (the fact that some functions are globally Lipschitz). This observer works either for autonomous systems or for nonlinear systems that are observable for any input. A tentative application to biological systems is described View full abstract»

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  • Adaptive nonlinear regulation: estimation from the Lyapunov equation

    Publication Year: 1992 , Page(s): 729 - 740
    Cited by:  Papers (240)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (876 KB)  

    A stabilizing adaptive controller for a nonlinear system depending affinely on some unknown parameters is presented. It is assumed that this system is feedback stabilizable. A key feature of the method is the use of the Lyapunov equation to design the adaptive law. A result on local stability, two different conditions for global stability, and a local result where the initial conditions of the state of the system only are restricted are given View full abstract»

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  • Robust control with respect to coprime factors of infinite-dimensional positive real systems

    Publication Year: 1992 , Page(s): 868 - 871
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (352 KB)  

    It is shown that infinite-dimensional positive real systems can be robustly stabilized with respect to coprime factor perturbations with a robustness margin of at least 1/√2. This result is applied to dissipative colocated systems which arise in PDE models of flexible structures View full abstract»

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  • Computation of the stability margin of two-dimensional discrete systems

    Publication Year: 1992 , Page(s): 824 - 827
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (260 KB)  

    Two methods of computing the stability margin of two-dimensional discrete systems are presented. The first method uses the Schur-Cohn stability criterion, and the second method is based on results concerning the 1-D Lyapunov equation with complex coefficients. Several examples illustrate the applicability of the two methods View full abstract»

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  • The area enclosed by the (oriented) Nyquist diagram and the Hilbert-Schmidt-Hankel norm of a linear system

    Publication Year: 1992 , Page(s): 835 - 839
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (380 KB)  

    It is shown that the Hilbert-Schmidt-Hankel norm (HSH-norm) of a transfer function of a stable system is equal, up to a constant factor, to the square root of the area enclosed by the oriented Nyquist diagram of the transfer function (multiplicities included). A generalization is presented for the case of systems which have no poles on the stability boundary, but otherwise have no restrictions on the pole locations View full abstract»

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  • Optimal control of admission to a multiserver queue with two arrival streams

    Publication Year: 1992 , Page(s): 785 - 797
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (916 KB)  

    The problem of finding an optimal admission policy to an M/M/c queue with one controlled and one uncontrolled arrival stream is addressed There are two streams of customers that are generated according to independent Poisson processes with constant arrival rates. The service time probability distribution is exponential and does not depend on the class of the customers. Upon arrival a class 1 customer may be admitted or rejected, while incoming class 2 customers are always admitted. A state-dependent reward is earned each time a new class 1 customer enters the system. When the discount factor is small, there exists a stationary admission policy of a threshold type that maximizes the expected total discounted reward over an infinite horizon. A similar result is also obtained when considering the long-run average reward criterion. The proof relies on a new device that consists of a partial construction of the solution of the dynamic programming equation. Applications arising from teletraffic analysis are proposed View full abstract»

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  • Vector norms as Lyapunov functions for linear systems

    Publication Year: 1992 , Page(s): 839 - 842
    Cited by:  Papers (37)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (332 KB)  

    A unified theory of quadratic and piecewise-linear Lyapunov functions for continuous and discrete-time linear systems is presented. The key to this work is the description of these Lyapunov functions by vector norms. The main results are sufficient and necessary conditions for a vector norm to be a Lyapunov function as well as a method (based on these conditions) of constructing such Lyapunov functions View full abstract»

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  • Robust stability of Lure systems with multiple nonlinearities

    Publication Year: 1992 , Page(s): 883 - 886
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (324 KB)  

    The stability of a perturbed Lure system is studied through the Popov-Lyapunov approach. The multivariable Popov criterion is used to guarantee the stability of the nominal system, and then the stability of the perturbed system is investigated by using the Lyapunov function developed for the nominal system. A robustness measure which gives some bounds on allowable perturbations for the system is derived, evading the use of norm forms. A feature of the proposed measure is that the observation of the range for individual parameter deviation is feasible View full abstract»

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  • Stability margin calculation for systems with structured time-delay uncertainties

    Publication Year: 1992 , Page(s): 865 - 868
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    A method of calculating a stability margin of systems with uncertain time-delay elements is presented. This method utilizes the bilinear transformation of time-delay elements to obtain a multilinear function in order to compute the stability margin by applying the mapping theory proposed for the robust stability test View full abstract»

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  • Identifying linear reduced-order models for systems with arbitrary initial conditions using Prony signal analysis

    Publication Year: 1992 , Page(s): 831 - 835
    Cited by:  Papers (31)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    A method of identifying reduced-order linear models for systems operating in the neighborhood of an equilibrium point is presented. The method is based on Prony signal analysis, which has recently received considerable attention in the study of power system electromechanical oscillations. Prior to the application of the input test signal, the system can be in a transient state. The system input test signal is piecewise continuous and allows several Prony analyses to be performed during a transient, with each analysis conducted between input discontinuities. Results of these Prony analyses can be combined in various ways to obtain system eigenvalues, transfer-function residues, and initial condition residues. Two examples are given to illustrate the use of the method 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