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Automatic Control, IEEE Transactions on

Issue 8 • Date Aug. 1992

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Displaying Results 1 - 25 of 36
  • Comments on "On the stability of uncertain polynomials with dependent coefficients by L.R. Pujara

    Publication Year: 1992
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    It is pointed out that the two main results in the above-titled paper (ibid, vol.35, pp.756-759, Jun 90) are closely related to a previously published result.<> View full abstract»

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  • Comments on "Robust pole placement direct adaptive control" by F. Giri et al

    Publication Year: 1992 , Page(s): 1273 - 1274
    Cited by:  Papers (1)
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    An improved proof is presented for the main result of the paper of Giri et al. (ibid., vol.34, no.3, p.356-9, Mar. 1989).<> View full abstract»

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  • Comments on "Stabilizability and detectability of discrete-time time-varying systems" by J.C. Engwerda [with reply]

    Publication Year: 1992 , Page(s): 1274 - 1275
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    In the original paper (ibid., vol.35, p.425-9, Apr. 1990), Engwerda analysed discrete-time and time-varying systems by resorting to systems that have time-varying order. Some comments are made on this issue. Moreover, Engwerda presented a counterexample which was claimed to contradict a result of B.D.O. Anderson and J.B. Moore (1981). The commenters show that such a counterexample does not actually entail any contradiction. In reply, Engwerda shows that there is an error in the work of Anderson and Moore that explains why his counterexample does not work.<> View full abstract»

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  • Complete instability of a box of polynomials

    Publication Year: 1992 , Page(s): 1230 - 1233
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (316 KB)  

    The authors study the converse of V.L. Kharitonov's polynomial problem (1978) by asking whether the complete instability of a box of polynomials can be determined from extreme sets. They show that it is not enough to check the (n-4)-dimensional boundary, but prove that the complete instability of the (n-1)-dimensional boundary is sufficient View full abstract»

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  • Robust H control for linear systems with norm-bounded time-varying uncertainty

    Publication Year: 1992 , Page(s): 1188 - 1191
    Cited by:  Papers (107)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (324 KB)  

    Robust H control design for linear systems with uncertainty in both the state and input matrices is treated. A state feedback control design which stabilizes the plant and guarantees an H-norm bound constraint on disturbance attenuation for all admissible uncertainties is presented. The robust H control problem is solved via the notion of quadratic stabilization with an H-norm bound. Necessary and sufficient conditions for quadratic stabilization with an H-norm bound are derived. The results can be regarded as extensions of existing results on H control and robust stabilization of uncertain linear systems View full abstract»

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  • Stability in feedback systems with tapered and other special input spaces

    Publication Year: 1992 , Page(s): 1256 - 1260
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (412 KB)  

    The effect of weighted input and output spaces on the stability of feedback systems is examined. For a weighted space, the recent past of a signal is emphasized and the remote past is deemphasized. Tapered spaces are a subclass of weighted spaces. Results concerning weighted spaces used on linear systems are given. The circle conditions are recovered for feedback systems with exponentially tapered spaces View full abstract»

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  • Construction of the maximal Schmidt pair for the 4-block H-optimal control problem

    Publication Year: 1992 , Page(s): 1250 - 1252
    Cited by:  Papers (3)
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    The maximal Schmidt pair for the 4-block H-optimal control problem is defined and constructed. The pair characterizes the case of highest gain in energy in the frequency domain, and is independent of any optimal solution View full abstract»

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  • Nonlinear feedback regulator design for the Cuk converter

    Publication Year: 1992 , Page(s): 1173 - 1180
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (676 KB)  

    The method of extended linearization is used for designing stabilizing nonlinear proportional-integral (PI) feedback controllers which regulate to a constant set-point value either the average output inductor current, the average input inductor current, or the average transfer capacitor voltage of a pulse width modulation (PWM) controlled Cuk converter. The design is carried out on the basis of the frequency-domain Ziegler-Nichols method, applied to a family of transfer function models of the linearized average PWM controlled circuit, parametrized by constant operating equilibrium points View full abstract»

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  • Singular value properties of LQ regulators

    Publication Year: 1992 , Page(s): 1210 - 1211
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (156 KB)  

    The closed-loop singular values of an LQ regulator transfer function are proved to be no greater than the singular values of the open-loop transfer function and, in the case of output-weighted cost function, to be no greater than the output-weighting parameter View full abstract»

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  • H control and quadratic stabilization of systems with parameter uncertainty via output feedback

    Publication Year: 1992 , Page(s): 1253 - 1256
    Cited by:  Papers (131)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (392 KB)  

    The article concerns linear systems which are subject to both time-varying norm-bounded parameter uncertainty and exogenous disturbance. It addresses the robust H control problem of designing a linear dynamic output feedback controller such that the closed-loop system is quadratically stable and achieves a prescribed level of disturbance attenuation for all admissible parameter uncertainties. It is shown that such a problem is equivalent to a scaled H control problem View full abstract»

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  • Observers for singular systems

    Publication Year: 1992 , Page(s): 1211 - 1215
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (380 KB)  

    The following three major aspects of the design of observers for linear time-invariant singular systems are resolved: the necessary and sufficient conditions for the problem to have a solution; the order of the minimal observer; and the properties of the closed-loop system (separation principle). An algorithm is presented for the construction of the minimal-order observer View full abstract»

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  • Comparison between H2 and H controllers

    Publication Year: 1992 , Page(s): 1261 - 1265
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (352 KB)  

    The H performances of a controller designed by H 2 methodology and a controller designed by H methodology are quantitatively compared. It is shown that the ratio of the H performance of the two is no greater than 2k for the one block problem, where k is the total number of right half plane transmission zeros for two subsystems namely the subsystem between the disturbance and the measurement and the subsystem between the control signal and the controlled output. It is also shown that there are systems which can give a ratio arbitrarily close to the upper bound. However, those systems are of a pathological type. Some possible generalizations to two- and four-block problems are discussed View full abstract»

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  • Stabilization of some distributed parameter systems

    Publication Year: 1992 , Page(s): 1184 - 1188
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (424 KB)  

    The question of stabilization of perturbed (or uncertain) infinite-dimensional systems is considered. One class of perturbations for which the system remains stabilizable by the same feedback law as for the nominal system is identified. Sufficient conditions are presented that generate strong stabilizability of the perturbed system given that the unperturbed system has similar properties. It is also shown that for deterministic as well as stochastic systems, exponential stability can be achieved by choice of a suitable feedback controller. The theoretical results are illustrated by some numerical examples View full abstract»

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  • Concurrency and state feedback in discrete-event systems

    Publication Year: 1992 , Page(s): 1180 - 1184
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (460 KB)  

    In parallel and/or distributed architectures, strict concurrency (simultaneity of events) may have critical implications for the validity of a proposed supervisory control law. The authors consider this problem in the Ramadge-Wonham framework of controlled automata. They derive a simpler description of the concept of weak interaction introduced in earlier work, together with new necessary and sufficient conditions for state-feedback control to remain valid in the presence of strict concurrency View full abstract»

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  • A new Lyapunov function for interconnected power systems

    Publication Year: 1992 , Page(s): 1192 - 1196
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (308 KB)  

    A Lyapunov function is constructed for a general n-machine power system with nonzero transfer conductance. The theory of dissipative dynamic systems and its modifications are used. The Lyapunov function construction procedure calls for checking positive definiteness of a sparse matrix. Results are reported only for the case of nonuniform damping, which is more complex than the uniformly damped system. The procedure is iterative and is guaranteed to converge for uniform damping but may fail to converge for a very lightly nonuniformly damped system with strong interconnections. The Lyapunov function is a quadratic term plus a weighted sum of integrals, a form not reported before. This is an extension of a previously reported quadratic Lyapunov function View full abstract»

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  • Design of a two-degree-of-freedom controller for motor drives

    Publication Year: 1992 , Page(s): 1215 - 1220
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (444 KB)  

    A two-degree-of-freedom controller for motor drives with a first-order model is proposed. The parameters of the controller are designed using a systematic procedure to match the prescribed motor drive specifications. Very good rotor speed dynamic responses of both the command tracking and load regulation characteristics can be achieved. A theoretic basis for the design procedure is derived in detail. Simulated and experimental results are given to demonstrate the effectiveness of the controller View full abstract»

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  • Robust stabilization in the gap metric: controller design for distributed plants

    Publication Year: 1992 , Page(s): 1133 - 1143
    Cited by:  Papers (31)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (872 KB)  

    The problem of robustness in the gap metric for infinite-dimensional systems is considered. The problem of computing the optimal controller and the optimal robustness radius for a class of systems whose normalized coprime factors have elements which are H functions with continuous boundary values is studied. The underlying Hankel and related operators, which are important in the gap optimization problem, are studied, and relations between their singular values and vectors are established. A computational approach to the optimal robustness problem is developed for single-input/single-output systems whose transfer function is an inner function in H times a rational function. The procedure is applied to a general first-order delay system and a closed-form formula is obtained for the optimal controller. The frequency response plots of the compensated system for various values of time delay are examined View full abstract»

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  • Control of serial sampling systems

    Publication Year: 1992 , Page(s): 1202 - 1205
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    In industrial multivariable plants, it is often the case that the plant outputs are detected not simultaneously but serially. The problem of estimating the state vector of the plant based on the data obtained from such a detection scheme is considered, and a special type of observer (referred to as a serial-sampling type) which renews its internal state whenever new data are obtained is proposed. The constructability of a serial-sampling observer and the stability of the closed-loop system which includes such an observer are theoretically studied View full abstract»

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  • On the connection between estimability and observability

    Publication Year: 1992 , Page(s): 1225 - 1226
    Cited by:  Papers (1)
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    It is shown that when a linear dynamic system is stochastically autonomous (that is, when the system is not excited by a random signal), its estimability property as defined by Y. Baram and T. Kailath (ibid., vol.33, p.1116-21, Dec. 1988) reduces to the classical observability property View full abstract»

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  • Multiplicative-error bound for balanced stochastic truncation model reduction

    Publication Year: 1992 , Page(s): 1265 - 1267
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (240 KB)  

    The multiplicative error for the balanced stochastic truncation model reduction method is discussed and an H norm error bound is presented. The result, together with a previous result of the authors (Syst. Contr. Lett., vol.14, p.307-14, 1990), establishes that the same error bound applies to the relative error and the multiplicative error View full abstract»

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  • Characterization of zero locations of polytopes of real polynomials

    Publication Year: 1992 , Page(s): 1227 - 1230
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB)  

    Given a stability region of a polytope of polynomials, the edge theorem can be used to verify certain root-clustering properties of the polytope. The authors consider the inverse problem; starting with a polytope of real polynomials, they present a result that allows the construction of the smallest set of regions in the complex plane which characterizes its zero location View full abstract»

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  • Reliable decentralized stabilization of feedforward and feedback interconnected systems

    Publication Year: 1992 , Page(s): 1119 - 1132
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1088 KB)  

    The synthesis of decentralized controllers that are reliable in the presence of breakdowns in the interconnections is considered for plants obtained via feedforward and feedback type interconnection schemes. The main objective is to determine the precise conditions on the plant which assure such reliable synthesis. It is shown that the central property for reliable decentralized stabilization is always an appropriate parity interlacing property among the poles of the interconnection subplants and certain blocking zeros of the overall plant. The conditions under which the stabilization of a two-channel plant is affected by the stabilization of its diagonal subplants are also obtained. The results also find application in multiple controller reliable synthesis problems. The discussion is restricted to two-channel plants View full abstract»

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  • Improved bounds for linear discrete-time systems with structured perturbations

    Publication Year: 1992 , Page(s): 1170 - 1173
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (296 KB)  

    A time-domain analysis of the stability robustness of linear discrete-time systems subject to time-varying structured perturbations is considered. The Lyapunov stability theory is used to obtain bounds on the perturbation such that the systems remain stable. It is shown that these bounds are less conservative than the existing ones. This is illustrated via two numerical examples View full abstract»

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  • Some bounds of the solution of the algebraic Riccati equation

    Publication Year: 1992 , Page(s): 1209 - 1210
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB)  

    Bounds on extremal eigenvalues and lower and upper bounds of the trace for the solution of the algebraic Riccati equation are presented. Through two examples, it is shown that, in some special cases, the presented bounds can be better than the results recently published View full abstract»

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  • Decentralized adaptive controller design for large-scale systems with higher order interconnections

    Publication Year: 1992 , Page(s): 1106 - 1118
    Cited by:  Papers (96)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (876 KB)  

    Decentralized robust adaptive controller designs for large-scale interconnected systems are investigated. Motivated by real mechanical systems, the authors consider a general representation of interconnections when the strength of the interconnections is bounded by a pth-order polynomial in states. This is in contrast to other studies which have made simpler assumptions about the strength of the interconnections. The authors investigate several scenarios as the control computations become more distributed until the controllers are completely decentralized. The possible bound of the interconnections is assumed to be known for the decentralized semiadaptive controller. Without the knowledge of these bounds, two adaptive controllers are designed: a decentralized adaptive controller with partially centralized compensation and a fully adaptive decentralized controller 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