By Topic

Automatic Control, IEEE Transactions on

Issue 6 • Date June 1984

Filter Results

Displaying Results 1 - 23 of 23
  • [Front cover and table of contents]

    Page(s): 0
    Save to Project icon | Request Permissions | PDF file iconPDF (169 KB)  
    Freely Available from IEEE
  • Editorial: A reviewer guide or the Transactions is as good as its reviewers

    Page(s): 481
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (146 KB)  

    Presents a guide for reviewers of Society's Transactions. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Reply to "On bootstrap estimation of system parameter and states"

    Page(s): 576
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (83 KB)  

    The author counters some objections raised by S. Ahmad (see ibid., vol. AC-28, pp. 805-806, 1983) to two earlier papers appearing respectively in Int. J. Syst. Sci., vol. 8, pp. 1365-1374 (1977) and IEEE Trans. Automatic Control, vol. AC-22, pp. 671-672 (1977). View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • [Back cover]

    Page(s): 0
    Save to Project icon | Request Permissions | PDF file iconPDF (132 KB)  
    Freely Available from IEEE
  • Minimax linear observers and regulators for stochastic systems with uncertain second-order statistics

    Page(s): 499 - 511
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1376 KB)  

    The problem of minimax design of linear observers and regulators for linear time-varying multivariable stochastic systems with uncertain models of their second-order statistics is treated in this paper. General classes of allowable covariance matrices and means of the process and observation noises and of the random initial condition are considered. A game formulation of the problem is adopted and it is shown that the optimal filter for the least favorable set of covariances is minimax robust for each of the filtering situations analyzed. Conditions satisfied by the saddle-point solutions are given, and their utility for finding the worst case covariances is illustrated by way of several examples of uncertainty classes of practical interest. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optimal control of two interacting service stations

    Page(s): 491 - 499
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (872 KB)  

    Optimal controls described by switching curves in the two-dimensional state space are shown to exist for the optimal control of a Markov network with two service stations and linear cost. The controls govern routing and service priorities. Finite horizon and long run average cost problems are considered and value iteration is a key tool. Nonconvex value functions are shown to exist for slightly more general networks. Nonconvex value functions are also shown to arise for a simple single station control problem in which the instantaneous cost is convex but not monotone. Nevertheless, optimality of threshold policies is established for the single station problem. The proof is based on a novel use of stochastic coupling and policy iteration. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Bilinear transformation by synthetic division

    Page(s): 575 - 576
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB)  

    A simple procedure for bilinear transformation by synthetic division is presented. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Quadratic-type Lyapunov functions for singularly perturbed systems

    Page(s): 542 - 550
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (840 KB)  

    Asymptotic and exponential stability of nonlinear singularly perturbed systems are investigated via Lyapunov stability techniques. A quadratic-type Lyapunov function for a singularly perturbed system is obtained as a weighted sum of quadratic-type Lyapunov functions of two lower order systems. Estimates of domain of attraction, of upper bound on perturbation parameter, and of degree of exponential stability are obtained. The method is illustrated by studying the stability of a synchronous generator connected to an infinite bus. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Near-optimum regulators for stochastic linear singularly perturbed systems

    Page(s): 531 - 541
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1080 KB)  

    This paper presents a new approach to the decomposition and approximation of linear-quadratic-Gaussian estimation and control problems for singularly perturbed systems. The Kalman filter is decomposed into separate slow-mode and fast-mode filters via the use of a decoupling transformation. A near-optimal control law is derived by approximating the coefficients of the optimal control law. The order of approximation of the optimal performance is0(mu^{N})whereNis the order of approximation of the coefficients. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A note on the complementary model of Weinert and Desai

    Page(s): 551 - 552
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (200 KB)  

    We use elementary concepts of linear least-squares estimation to obtain a direct derivation of the so-called complementary model of Weinert and Desai [1]. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Controllability of nonlinear systems consisting of a bilinear mode with distributed delays in control

    Page(s): 573 - 575
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (256 KB)  

    Sufficient conditions for global relative controllability, of nonlinear systems consisting of a bilinear mode with distributed delays in control are given. Results for bilinear systems with multiple delays and general nonlinear systems with distributed delays in control are stated. Proofs are based on Schauder's fixed point theorem. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Deviation variables in linear multivariable servomechanisms

    Page(s): 567 - 569
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB)  

    Deviation variables have been utilized to simplify the analysis and synthesis of observer-based multivariable servomechanisms. It has been shown that internal stability and output regulation are dictated by the asymptotic behavior of the deviation variables. Similar characterizations are unavailable in the compensator-based approach to servomechanism design. In this note, we introduce a set of deviation variables for the analysis and synthesis of compensator-based servomechanisms. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On the open-loop solution of linear stochastic optimal control problems

    Page(s): 562 - 564
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB)  

    We consider open-loop solutions of linear stochastic optimal control problems with constraints on control variables and probabilistic constraints on state variables. It is shown that this problem reduces to an equivalent linear deterministic optimal control problem with similar constraints and with a new criterion to minimize. Concavity or convexity is preserved. Hence, the machinery available for solving deterministic optimal control problems can be used to get an open-loop solution of the stochastic problem. The convex case is investigated and a bound on the difference between closed-loop and open-loop optimal costs is given. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Noncausal minimax linear state estimation for systems with uncertain second-order statistics

    Page(s): 555 - 557
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB)  

    This note considers the problem of minimax state estimation of the states of a linear time-invariant system which is driven by and observed in the presence of noise processes with uncertain second-order statistics. When the process noise and observations are scalars, the problem is shown to be equivalent to a scalar minimax estimation problem. The existence of a minimax solution is thereby established, and the minimax filter is shown to be a linear transformation of the minimax filter for the scalar problem. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On the stabilization of nonlinear systems

    Page(s): 569 - 572
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (400 KB)  

    We extend the applicability of the globalQ-parametrization method of controller design to a large class of unstable nonlinear plants. The main result is a two-step compensation theorem analogous to that of Zames for unstable linear plants-ifP: L_{e2} rightarrow L_{e1}is a nonlinear (possibly unstable) plant and F0is any incrementally stable controller such thatP_{1}:=P(I - F_{0}(-P))^{-1}is incrementally stable, then the class of controllersFwhich yields an f.g. stable closed-loop system in the unity feedback configuration forPis globally parametrized by finite gain stable mapsQ: L_{e1} rightarrow L_{e2}withF = F_{0} + Q(I - P_{-1}Q)^{-1} View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Multilayer control system design applied to freeway traffic

    Page(s): 482 - 490
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (944 KB)  

    After a qualitative discussion of properties of on-line control schemes, such as closed-loop, open-loop and two-stage approach, for large-scale nonlinear plants, a multilayer structure is proposed for on-line control of nonlinear plants with measurable slow disturbances leading to good control performance even under occurrence of unexpected disturbances. The multilayer structure is applied to the freeway traffic control problem. Simulation results show the superiority of the resulting control actions compared to previous solutions. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On feedback free stochastic processes

    Page(s): 560 - 562
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    We consider the problem of modeling the interaction between stochastic processes using only second-order statistics. We represent the variables as Hilbert space valued stochastic processes and use the technique of resolution spaces. Thus, we are able to build the causality requirement directly into the problem. Our approach is constructive and applies equally well to stationary and nonstationary processes. The condition of causality is very useful in determining the structure of the system generating the observed variables. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Weiner and Kalman filters for systems with random parameters

    Page(s): 552 - 554
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (296 KB)  

    A linear stationary optimal filtering problem is considered in which the plant dynamics and noise covariances are incompletely known. Unknown plant parameters in the plant model, such as gains and time constants, are treated as random variables with specified means and variances. Generalized Wiener and Kalman-Bucy filters are derived on the basis of transfer-function matrix or state-space representations of the plant, respectively. An application of the generalized filter to the linear quadratic optimal control of plants with unknown disturbances is also described and a certainty equivalence principle is shown to apply. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A lower bound on the estimation performance for stochastic control systems

    Page(s): 557 - 559
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    A lower bound is derived on the mean-square-error in estimating the state of a nonlinear, stochastic, feedback-control system from nonlinear, non-Gaussian measurements. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Algebraic theory for robust stability of interconnected systems: Necessary and sufficient conditions

    Page(s): 511 - 519
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (832 KB)  

    We consider an interconnected system Somade of linear mulrivariable subsystems which are specified by matrix fractions with elements in a ring of stable scalar transfer functionsH. Given that thekth subsystem is perturbed fromG_{k} = N_{rk}D_{k}^{-1}totilde{G}_{k} = (N_{rk} + Delta N_{rk})(D_{k} + Delta D_{k})^{-1}and that the system SoisH-stable, we derive a computationally efficient necessary and sufficient condition for theH-stability, of the perturbed system. These fractional perturbations are more general than the conventional additive and multiplicative perturbations. The result is generalized to handle simultaneous perturbations of two or more subsystems. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Robust compensation for a robotic manipulator

    Page(s): 564 - 567
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB)  

    In a suboptimally controlled manipulator arm, friction torque variations cause trajectory deviations and performance deterioration. On the other hand, the on-line computation of nonlinear terms of the suboptimal controller is time consuming or requires large memory space when table lookup techniques are used. In order to obtain robustness against variations in open-loop dynamics and decrease the effect of nonlinear terms due to couplings in suboptimal control systems with quadratic performance indexes, in addition to state proportional feedback, it is necessary to introduce feedback associated with the derivatives of the state variables. This additional feedback may be implemented as minor compensating loops built around the individual joints with analog devices. As an example, torque compensation and acceleration compensation for the M.I.T. Scheinman arm are considered. They yield a simple linear controller with improved robustness. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A simple stochastic control problem with anticipation

    Page(s): 559 - 560
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (240 KB)  

    We consider in this note a particular case of the problem of stochastic optimal control when the state noise is a Brownian motion process(w_{z}), z in [0,1]and the value of (w1) is known a priori. An example of application is given in terms of spatial noises. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Controller reduction by component cost analysis

    Page(s): 520 - 530
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (960 KB)  

    Component cost analysis [1] is used to develop a method for controller reduction. The reduction of the controller is based upon the participation of the controller states in the value of a quadratic performance metric. The controller states which have the smallest contribution to the performance metric are truncated to produce the reduced controllers. An error index is defined to evaluate the reduced controller compared to the optimal LQG controller, and bounds on this index are derived. A numerical example is included to illustrate the procedure. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

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

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
P. J. Antsaklis
Dept. Electrical Engineering
University of Notre Dame