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Showing papers in "Automatica in 1973"


Journal ArticleDOI
TL;DR: In this paper, the problem of controlling a system with constant but unknown parameters is considered and an algorithm obtained by combining a least squares estimator with a minimum variance regulator computed from the estimated model is analyzed.

1,404 citations


Journal ArticleDOI
TL;DR: In this paper, a computer-aided procedure whereby a succession of single-loop designs, using Nyquist loci, yields a multivariable design which is stable and attenuates disturbances is described.

182 citations


Journal ArticleDOI
TL;DR: A survey of the field of data smoothing for linear and nonlinear, dynamic systems is presented in this paper, starting with the work of Kepler and Gauss, proceeding through that of Kolmogorov and Wiener, and concluding with studies of numerous researchers during the past 10-12 years.

160 citations


Journal ArticleDOI
TL;DR: The Characteristic Locus Method as discussed by the authors combines the essence of these two approaches by exploiting the properties of linear vector spaces defined over base fields of functions of a complex variable, and then emerges a general vector feedback theory in which the classical Bode-Nyquist technique is a special case.

153 citations


Journal ArticleDOI
TL;DR: In this paper, Kalman filtering results are applied to yield alternative computationally stable fixed-lag smoothing algorithms including reduced order and minimal order fixedlag smoothers, which clearly have advantages over the more familiar algorithms.

120 citations


Journal ArticleDOI
TL;DR: In this article, the controllability of a class of time invariant discrete bilinear systems is investigated by decomposing the system into a linear system and a multiplicative feedback.

109 citations


Journal ArticleDOI
TL;DR: In this article, an adaptive control algorithm for linear systems with unknown constant parameters and quadratic performance criterion has been obtained, where the control is nonlinear in the estimate of the state of the plant and is given as the weighted integral of the model conditional optimal controls with the a-posteriori probabilities as weights.

100 citations


Journal ArticleDOI
W. A. Wolovich1
TL;DR: In this paper, a new, relatively simple, constructive method is presented for obtaining state-space or normal form representations for linear, time invariant systems whose dynamics are expressed in a more general matrix differential operator form.

93 citations


Journal ArticleDOI
TL;DR: In this article, three different forms of Liapunov functions are used for describing the stability behavior of the aggregated system, but one form in particular, heretofore not used in this context, is found to be the most natural.

91 citations


Journal ArticleDOI
TL;DR: From both the computational and storage aspects, the approach offers an effective alternative for SVIC problems and extensions of the algorithm to more general control problems are suggested.

89 citations


Journal ArticleDOI
TL;DR: Criteria for the existance of observers for linear, time-invariant systems where some of the inputs are unmeasurable and statistically unknown are developed and an example is presented.

Journal ArticleDOI
TL;DR: In this paper, necessary and sufficient conditions are derived for a stable feedforward control system to exist for a multivariable linear time-invariant system so that: (1) any measurable disturbances occurring in the system are asymptotically rejected, and (2) the outputs of the system asymPTotically become equal to preassigned functions of a given class of outputs.

Journal ArticleDOI
TL;DR: The paper derives a result connecting frequency-domain and time-domain properties of different spectral factors of the one power spectrum matrix, interpreted from an algebraic point of view, and applied to the linear-quadratic optimal control and filtering problem.

Journal ArticleDOI
TL;DR: Three optimization schemes for estimating the unknown parameters in distributed parameter systems are discussed, including a steepest descent method, a search technique, and nonlinear filtering.

Journal ArticleDOI
TL;DR: Two methods of simulating continuous-data systems by sampled-data models are presented; one relies on the optimization of the sampled- data system with a quadratic performance index, and another relies on a point-by-point comparison method.

Journal ArticleDOI
TL;DR: A design procedure is presented wherein one works backwards step by step from the system output, designing each loop function L"i almost as if the remaining loops (L"i"+"j, j>0) are perfect.

Journal ArticleDOI
TL;DR: For linear multivariable control systems, the question of observing the state by means of sampling with arbitrary but fixed choice of the sampling instants is discussed in this paper, where the freedom due to this arbitrary choice is used to derive criteria for a choice of a sampling Instants which is as advantageous as possible as far as the propagation of measuring errors is concerned.

Journal ArticleDOI
TL;DR: The prediction schemes are used to obtain one-day-ahead forecasts of the Wabash River in the U.S.A. by using the daily riverflow data, paying particular attention to the choice of the order of the stochastic difference equation.

Journal ArticleDOI
TL;DR: In this article, the authors summarize results for linear multivariable systems that are analogous to those single input single output systems which are ''type l'', i.e. that contain l integrators.

Journal ArticleDOI
TL;DR: In this paper, a solution is given to yield reset control action in multivariable control systems, where the controller consists of a state reconstructor and feedback from estimated process and environmental states, and if a special choice for the ''feedforward'' matrix operating on the estimated environmental states is made, integral, or reset, control action results.

Journal ArticleDOI
TL;DR: In this article, a systematic design procedure for determining realistic feedforward feedback control systems for large multivariable linear constant systems is outlined, and a numerical example of a boiler system and a distillation column is included and a comparison of the simulated response of the controlled systems obtained by the proposed method is made with the corresponding conventional control systems.

Journal ArticleDOI
TL;DR: The literature abounds with papers on feedforward control of distillation columns as discussed by the authors, however, few of these papers discuss successful commercial applications, which has created a credibility gap between the control engineer and universities on one hand; and the engineers responsible for operating the columns on the other.

Journal ArticleDOI
TL;DR: The proposed algorithm has a truncation error of 0(h"5) where h is the step-size, is numerically stable for any h provided the original system is stable and the Lipschitz constant is small enough, and will give exact steady-state solutions for constant input systems for anyh.

Journal ArticleDOI
TL;DR: In this paper, the authors describe a flowmeter that consists of a bistable fluid amplifier which is made to oscillate by interconnecting the two control ports, and the operation of the flowmeter is explained with particular emphasis on the dimensionless characterization of periodic flows as derived from the Navier-Stokes Equations.

Journal ArticleDOI
TL;DR: In this paper, a new computational approach for optimization of linear time-delay (differential-difference) systems with quadratic indices is presented, which utilizes parameter imbedding, and transforms the advanced-delayed type two point boundary value form of necessary conditions to a sequence of conventional non-delay linear boundary value problems.

Journal ArticleDOI
TL;DR: In this article, the authors introduced the concept of predictable directions along which the solution goes to zero rather than a nonzero constant, and showed how to convert constant directions to predictable directions and how the concept may be extended to time-variant systems.

Journal ArticleDOI
TL;DR: A method is introduced for the linear balance calculation and distribution of measurement errors in complex systems with the inclusion of process dynamics by deducing a matrix difference equation that is a dynamic equivalent of the steady state balance equations.

Journal ArticleDOI
TL;DR: In this paper, the authors describe a systematic analysis which has been carried out on a commercial ammonia synthesis plant and a new concept-the ''stability margin''-which is an extension of the ideas of Van Heerden [8] is found to lead to a fuller appreciation of the properties of the models.

Journal ArticleDOI
TL;DR: In this article, the discrete optimal control problem with multiple inequality constraints on functions of the state and/or control variables is presented, where the time interval may be split up into segments over which the number of dominant constraints does not exceed the total number of control variables.

Journal ArticleDOI
TL;DR: In this paper, a method is proposed for the identification of distributed parameter systems using non-linear programming to minimize the integral of the weighted error squared over an observation interval, and an exponential form for the weighting function is used.