Plant Identification through Sinusoidal Response
TL;DR: In this article, a technique for identifying signals corresponding to the change in parameters of a linear third-order closed loop system has been described using sinusoids as a test signal.
Abstract: A technique for identifying signals corresponding to the change in parameters of a linear third-order closed loop system hag been described using sinusoids as a test signal. An application of this technique to an adaptive system has been indicated.
Citations
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TL;DR: A survey of the recent literature in the area of process identification and parameter estimation techniques applicable to lumped-parameter, deterministic, dynamical systems and a guide to particular applications which will assist the reader in selecting the best method for his specific problem.
Abstract: This paper represents a survey of the recent literature in the area of process identification and parameter estimation techniques applicable to lumped-parameter, deterministic, dynamical systems. Methods reviewed include statistical estimation techniques, direct and indirect methods based on optimal control theory, functional expansion, impulse response, frequency response and a number of other specific methods. Each method is presented in a consistent format which includes an outline of the general characteristics, calculational techniques, experimental techniques, reliability estimates and applications. The overall objective is to provide a basis for comparison of the methods and a guide to particular applications which will assist the reader in selecting the best method for his specific problem Comments and additions are solicited: see page 263.
65 citations
TL;DR: In this paper, an analogue computer sot-up which acts as a delayor is suggested for evaluation of the coefficients of the input and output of a linear differential equation of the system.
Abstract: The dynamic performance of many physical systems is adequately described by an ordinary linear differential equation of the form: where x(t) is the forcing function or the input to the system and y(t) is the response on the output of the system. If the coefficients a i , referred to as the parameters of the system, are known then the system is said to be completely known. In this investigation a method is suggested to evaluate these coefficients by performing measurements on the input and output of the system. The method suggested hero is the inverse of what is known as the method of undetermined coefficients. If the input is a polynomial in t then the steady state response of the system is also a polynomial in t. Knowing the coefficients of the input and output the system parameters a i can be evaluated. An analogue computer sot-up which acts as a delayor is suggested for evaluation of the coefficients of the input and output. The general scheme is given which can be used for continuous tracking of the s...
3 citations
TL;DR: The excitation of series, parallel, and pi mode analog models by deterministic stimuli is reviewed and a low-order model is shown to be perfectly adequate for dynamic performance checkout of a complex noisy nonlinear system.
Abstract: Analog models provide a cheap and effective method for identification and checkout of a wide range of physical systems via the transfer function concept. This paper reviews the excitation of series, parallel, and pi mode analog models by deterministic stimuli. Errors between the system and model responses may be displayed on a cathode-ray tube, or on an instrument measuring mean-error modulus. Novel methods of tuning the model coefficients by observing the error displays are described and evaluated experimentally. The checkout strategy is particularly suitable for use by technicians since reliable repeatable models are obtained independent of the level of operator understanding of the system under test. These models may then be used as input data for quality control of production items and for preventive maintenance schemes during the life of the system under test. A low-order model is shown to be perfectly adequate for dynamic performance checkout of a complex noisy nonlinear system. Intermediate access points then permit elemental modeling down to replaceable units. For adequate confidence in system dynamic performance, checkout tolerances placed on the model coefficients must be conditional and a suitable tolerance flow chart is included. Although presented on the basis of manual instrumentation, the methodology is suitable for automation and is applicable to self-adaptive systems in which system dynamics change slowly with time.
2 citations
Cites background from "Plant Identification through Sinuso..."
...Obviously more lowmoduli wouldbebetter, butthefrequencies chosen representa reasonable compromise andarethoseincorporated in theflowdiagram ofFig.7,whichshould becompared with thecomplicated routine required formodeling a simpler systemin[ 16 ]....
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References
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01 Jun 1963
TL;DR: Experimental results show that by properly filtering and measuring the response of the system to this optimized probing signal, the authors may detect and independently measure the simultaneous deviations in the system parameters.
Abstract: In this investigation a variant of the system identification problem has been solved using growing exponentials as the input signal to the system. The system contained two parameters whose values could be varied above and below nominal values. A probing signal basis composed of growing exponentials was matched to the space of patterns defined by small variations in the parameters of the system. The optimum probing signal within the signal space was then selected so as to minimize the covariance matrix of the errors in the measurement of these parameters as the optimizing criterion. Experimental results show that by properly filtering and measuring the response of the system to this optimized probing signal, we may detect and independently measure the simultaneous deviations in the system parameters.
31 citations
TL;DR: It is shown that increased speed of adaptive loop response is possible with high-frequency perturbation of model parameters, and the feasibility of adaptive control with random system input, and random parameter disturbances is shown.
Abstract: Theoretical and simulation studies of a parameter-perturbation self-adaptive system are discussed A number of system block diagrams are included, showing diverse applications of parameter-perturbation adaptive techniques A particular study has been made using error signals based on an ideal model, and the concept of high-frequency perturbation of the model has been introduced A linearized mathematical model of the adaptive loop for the system-adaptive scheme has been obtained using time-varying system analysis Experimental verification of the mathematical model has been obtained with an analog computer It is shown that increased speed of adaptive loop response is possible with high-frequency perturbation of model parameters Simulation studies have also shown the feasibility of adaptive control with random system input, and random parameter disturbances
26 citations
TL;DR: This paper describes a system for determining the parameters of a transfer function of the form: a constant divided by a polynomial in the Laplacian variable s .
Abstract: This paper describes a system for determining the parameters of a transfer function of the form: a constant divided by a polynomial in the Laplacian variable s . The system is described in detail for a polynomial of second order, but may be extended to polynomials of any order. The system may be realized in terms of ordinary analog computer components. It presents the information in a form which may be readily inserted into a controller for realization of a general type of adaptive control system.
15 citations