By Topic

Automatic Control, IEEE Transactions on

Issue 5 • Date May 1984

Filter Results

Displaying Results 1 - 25 of 26
  • [Front cover and table of contents]

    Publication Year: 1984 , Page(s): 0
    Save to Project icon | Request Permissions | PDF file iconPDF (176 KB)  
    Freely Available from IEEE
  • [Back cover]

    Publication Year: 1984 , Page(s): 0
    Save to Project icon | Request Permissions | PDF file iconPDF (131 KB)  
    Freely Available from IEEE
  • Convergence properties of LMS adaptive estimators with unbounded dependent inputs

    Publication Year: 1984 , Page(s): 477 - 479
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (368 KB)  

    This note presents limit theorems for the behavior of adaptive estimators using the LMS algorithm when the driving or input sequence is a member of a broad class of random processes which are not necessarily almost surely bounded and are dependent over time. Convergence in distribution of the estimates is established in the stationary case while general nonstationary tracking is characterized in the nonstationary case. These results follow from the exponential convergence of the homogeneous algorithm which in turn follows from a strong limit theorem for infinite products of ergodic and mixing sequences of matrices. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A globally stable APCS in the presence of bounded noises and disturbances

    Publication Year: 1984 , Page(s): 461 - 464
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    This paper presents a globally stable adaptive predictive control system (APCS) for discrete linear processes with pure time delays in the presence of bounded measurement and process noise plus unmeasured disturbances. The main contribution is the proof of stability in the context of discrete adaptive control schemes. This proof is based on the minimization of the a posteriori estimation error and the convergence of the estimated parameters. View full abstract»

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

    Publication Year: 1984 , Page(s): 455 - 457
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB)  

    We study the problem of simultaneous stabilization of a given set of nonlinear plants by one nonlinear, not necessarily stable compensator. We obtain a necessary and sufficient condition under which there is a single compensator which stabilizes a given set of n nonlinear plants. This note emphasizes the importance of the following problem: when is a nonlinear unstable plant stabilizable by an incrementally stable compensator. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On controllability and observability of time delay systems

    Publication Year: 1984 , Page(s): 432 - 439
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (760 KB)  

    This paper deals with controllability and observability properties of time delay systems in the state space R^{n} \times L^{p} . In particular, we prove the equivalence of spectral controllability and approximate null-controllability. Moreover, it is shown that the necessary, condition for approximate F- controllability-obtained recently by Manitius-is also sufficient, and a verifiable and matrix type criterion for F -controllability is derived for systems with commensurate delays. Finally, we introduce the dual observability notion of approximate controllability and prove that the control system Σ is exactly null-controllable if and only if the transposed delay system ΣTis continuously finally observable. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A new criterion of controllability

    Publication Year: 1984 , Page(s): 444 - 446
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    A new criterion of controllability based on matrix symmetrization is proposed. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Computation of differential equation particular solutions with application to sigma plots

    Publication Year: 1984 , Page(s): 457 - 459
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    This paper shows that the problem of determining the particular solution to a linear differential equation with constant coefficients can be recast as a model-following problem. The model-following problem can be solved using feedforward control theory. The computation of the frequency response of a plant is formulated as a special type of differential equation particular solution. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • d-step lattice-ladder predictor in terms of one-step lattice-ladder predictors

    Publication Year: 1984 , Page(s): 464 - 465
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (208 KB)  

    In this note, it is shown that a d -step lattice-ladder predictor may be expressed in terms of one-step lattice-ladder predictors. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Linear approximation of transfer function with a pole of fractional power

    Publication Year: 1984 , Page(s): 441 - 444
    Cited by:  Papers (40)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB)  

    Two methods for the linear approximation of a transfer function with a pole of fractional power are presented. Analog circuit models are developed, and their frequency response curves and step response curves are compared. It was found that the Padé method gives a better approximation than Wang and Hsia's method within the frequency limit as specified. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The graph metric for unstable plants and robustness estimates for feedback stability

    Publication Year: 1984 , Page(s): 403 - 418
    Cited by:  Papers (88)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1640 KB)  

    In this paper, a "graph metric" is defined that provides a measure of the distance between unstable multivariable plants. The graph metric induces a "graph topology" on unstable plants, which is the weakest possible topology in which feedback stability is robust. Using the graph metric, it is possible to derive estimates for the robustness of feedback stability without assuming that the perturbed and unperturbed plants have the same number of RHP poles. If the perturbed and unperturbed systems have the same RHP poles, then it is possible to obtain necessary and sufficient conditions for robustness with respect to a given class of perturbations. As an application of these results, the design of stabilizing controllers for unstable singularly perturbed systems is studied. Finally, the relationship of the graph metric to the "gap metric" introduced by Zames and El-Sakkary is studied in detail. In particular, it is shown that the robustness results of Zames and El-Sakkary do not enable one to conclude the causality, of the perturbed system, whereas the present results do. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The all-pass property of optimal open-loop tracking systems

    Publication Year: 1984 , Page(s): 465 - 467
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    The structure of the optimal open-loop linear model-following system is investigated. It is shown that if the given plant is asymptotically stable but has zeros in the right half-plane, the stable optimal system contains an all-pass network whose transference possesses unity, singular values on the imaginary axis. In the special case of optimal tracking, it is shown that the resulting optimal transfer function matrix of the system is equal to the all-pass transfer function matrix which is normalized to be the identity matrix at the zero frequency. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Bifurcations in the frequency response of nonlinear feedback control systems

    Publication Year: 1984 , Page(s): 450 - 452
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    The bifurcation theory is applied to bifurcations and accompanying jump phenomena which appear in the frequency response of nonlinear feedback control systems. It is also shown by a numerical example that such complicated structures exist in the frequency response of a simple nonlinear feedback control system. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • General approach to linear optimal estimator of finite number of parameters

    Publication Year: 1984 , Page(s): 470 - 472
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    A system is considered whose output depends linearly on the pair: finite parameter vector and control. The control and the output belong to some Hilbert spaces. We formulate two problems. The first is in what way one can obtain the parameter vector, under known control and suitable output generated by this control. This problem is called the estimator problem. The second is how to obtain an estimator optimal with respect to disturbed measurements of output and control. We show an application of our results to state observation in dynamic systems. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Error feedback and internal models on differentiable manifolds

    Publication Year: 1984 , Page(s): 397 - 403
    Cited by:  Papers (29)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (584 KB)  

    Structural aspects are studied of nonlinear control systems in a setting of differentiable manifolds. As a generalization of the setup commonly used in linear multivariable control, the regulator problem is defined as that of controlling a fixed plant to track (or reject) reference (or disturbance) signals generated by a fixed dynamic model called the exosystem. It is shown that, if the controller is error-driven, if perfect tracking is achieved in the limit t \rightarrow \infty , and if a suitable observability condition is present, then the controller necessarily incorporates a copy (internal model) of the exosystem dynamics. This result represents a counterpart in the nonlinear differentiable setting to various results already known for linear systems and for abstract automata. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The influence of finite word length on digital optimal control

    Publication Year: 1984 , Page(s): 385 - 391
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (688 KB)  

    This paper is concerned with the performance of linear discrete-time systems, controlled by a finite word length computer with floating-point arithmetic, and of which the state is directly measurable with an A/D converter of the same word length. The effect of using finite word length is twofold. First, roundings are made after addition or multiplication of two rounded numbers. Second, the control parameters are represented in the controller's memory, by rounded numbers. The first effect can be accounted for by considering the control parameters stochastic. The second effect is deterministic. After a description of the stochastlcs of the roundoff errors has been derived, the influence of both effects on the optimality and stability of digital control systems in the steady state in relation to a quadratic cost function is considered. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Functional reproducibility in nonlinear systems using dynamic compensation

    Publication Year: 1984 , Page(s): 446 - 450
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (472 KB)  

    A new sufficient condition for the existence of a control to generate a given real analytic function as the output of multivariable nonlinear systems with dynamic compensation is derived. Furthermore, a prefilter (right-inverse system) is constructed to generate the required control. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Linear compensator design for bounded input-bounded output stability of nonlinear systems

    Publication Year: 1984 , Page(s): 452 - 455
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB)  

    A method of determining a cascade compensator in a nonlinear feedback system to provide BIBO stability is discussed. The procedure is based on the Popov locus. Two examples are included to illustrate the method. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On consistent estimation of the characteristic coefficient and the poles of multivariate linear systems

    Publication Year: 1984 , Page(s): 479 - 480
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (160 KB)  

    The estimation of the characteristic coefficients and the poles of linear systems is considered. It is shown that estimates obtained from the sample correlation function of possibly nonstationary multivariable observations are consistent. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On the structure of state-space models for discrete-time stochastic vector processes

    Publication Year: 1984 , Page(s): 418 - 432
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1696 KB)  

    From a conceptual point of view, structural properties of linear stochastic systems are best understood in a geometric formulation which factors out the effects of the choice of coordinates. In this paper we study the structure of discrete-time linear systems with stationary inputs in the geometric framework of splitting subspaces set up in the work by Lindquist and Picci. In addition to modifying some of the realization results of this work to the discrete-time setting, we consider some problems which are unique to the discrete-time setting. These include the relations between models with and without noise in the observation channel, and certain degeneracies which do not occur in the continuous-time case. One type of degeneracy is related to the singularity of the state transition matrix, another to the rank of the observation noise and invariant directions of the matrix Riccati equation of Kalman filtering. We determine to what extent these degeneracies are properties of the output process. The geometric framework also accommodates infinite-dimensional state spaces, and therefore the analysis is not limited to finite-dimensional systems. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Recursive algorithms for Bayes smoothing with uncertain observations

    Publication Year: 1984 , Page(s): 459 - 461
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB)  

    Recursive algorithms for the Bayes solution of fixed-interval, fixed-point, and fixed-lag smoothing under uncertain observations are presented. The Bayes smoothing algorithms are obtained for a Markovian system model with Markov uncertainty, a model more general than the one used in linear smoothing algorithms. The Bayes fixed-interval smoothing algorithm is applied to a Gauss-Markov example. The simulation results for this example indicate that the MSE performance of the Bayes smoother is significantly better than that of the linear smoother. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Root locus near isolated pole-zero dipoles and a counterintuitive case of digital control compensation

    Publication Year: 1984 , Page(s): 439 - 441
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (280 KB)  

    A convenient characterization is given for root loci associated with open-loop pole-zero dipoles. A particular dipole-locus effect is shown to influence the design of a digital PID controller for an oscillatory plant; the design is a counterintuitive one in which zeros of the compensator are placed outside the unit circle in the neighborhood of the plant poles. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Quadratic open-loop optimal control of economic systems

    Publication Year: 1984 , Page(s): 392 - 396
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (664 KB)  

    This paper exploits the formal analogy between least-squares estimation and quadratic open-loop control to impose a variety, of restrictions, to gain insight into problems of numeric instability, and to propose indexes of policy effectiveness and the importance of instrument costs to the solution. In addition, it provides an open-loop stochastic control solution with computational advantages in certain situations. Although the emphasis is on control problems in economics, the results are believed to be of general interest. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Proper rational matrix diophantine equations and the exact model matching problem

    Publication Year: 1984 , Page(s): 475 - 477
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (360 KB)  

    Relying on the theory behind the Smith-MacMillan form of a rational matrix at s = \infty , a necessary and sufficient condition is derived from the solvability of matrix Diophantine equations of the form A(s)X(s)+B(s)Y(s) = M(s) , where A(s), B(s) , and M(s) are given proper rational matrices and X(s) and Y(s) are unknown proper rational matrices. It is shown that the above result can be used in order to resolve in a new illuminating way the exact model matching problem (EMMP). If a solution to EMMP exists, then the family of all solutions is parametrized. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A skew-symmetric formulation of the algebraic Riccati equation problem

    Publication Year: 1984 , Page(s): 467 - 470
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (400 KB)  

    By introducing a set of matrix transformations a new canonical representation in the field of real skew-symmetric matrices is obtained for the algebraic Riccati equation. As a consequence of this reformulation closed-form analytical solutions are derived in R^{2 \times 2} or when some special commutativity conditions are fulfilled in the transformed space. The formulation extends the results of [6] to a wider class of Riccati equations. 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