摘要:

The paper studied the problem of the adaptive tracking of a reference signal by the output of any deterministic discrete SISO linear system with unknown parameters. An adaptive control scheme, based on the LQ control solution, is proposed. The stability of the resulting adaptively controlled system and conditions for a good tracking are studied. Several simulations illustrate the proposal.

ISSN:0020-7179    

DOI:10.1080/00207178208922599

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The local behaviour of root loci around zeros and poles is investigated. This is done by relating the Newton diagrams which arise in the local analysis to the McMillan structure of the open-loop system, by means of what we shall call the McMillan polygon. This geometric construct serves to clarify the precise relationship between the McMillan structure, the principal structure, and the branching patterns of the root loci. In addition, several rules are obtained which are useful in the construction of the root loci of multivariable control systems.

ISSN:0020-7179    

DOI:10.1080/00207178208922600

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The deterministic mathematical model for two competing biological species is described by the Lotka-Volterra non-linear differential equations. These have been derived with the assumption of two linear functions to represent the diminutions in the Malthusian net growth rates resulting from the effects of self-inhibition and competition. Firstly, a generalized model assuming non-linear forms for these functions is proposed here, and is shown to lead to differential equations of the same form as the original L-V equations. In a previous paper presenting a competition model with time-varying rates, a certain integrable class of the appropriate non-autonomous differential equations was also reduced to the autonomous L-V equations. As these latter are thus seen to arise in cases other than the original case for which they have been derived, we give here six more exact solutions (six were previously given by the author). Secondly, we generalize the original L-V equations in another direction by considering immigration and emigration of one or both species at constant rates. For these equations we have obtained over fifty exact solutions, six of which are here given.

ISSN:0020-7179    

DOI:10.1080/00207178208922601

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A Langevin differential equation which has a damping term and a control force both varying periodically at the same frequency, the equation being forced by an arbitrary function of time, is considered in this paper. The solution of the equation is reduced to that of a second-order linear differential equation in either the real or the complex domain ; no approximation is involved in this reduction, for it is exact. In particular, for the autonomous equation the exact solution shows that no limit cycles exist, contrary to the approximate results obtained by Ottoy for the equation whoso damping term fluctuates at twice the frequency of the control force. Next, a Langevin equation which is forced by a periodically fluctuating function of time (having arbitrary amplitude and frequency) is solved exactly when some of the parameters are interrelated in four distinct ways.

ISSN:0020-7179    

DOI:10.1080/00207178208922602

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A new interpretation and solution of the linear multivariate steady-state tracking and disturbance rejection problem is presented. On condition of reference and disturbance input variables with constant final values the proposed method prepares the ground for the calculation of a constant feedback control law, which meets the steady-state requirements exactly, although doing without the conventional prefilter or integral feedback respectively. Nevertheless the practical design reduces to the standard problem of stabilizing a precontrolled system by fictitious constant output feedback. The method is illustrated by the examples of a fourth-order nuclear rocket engine and a twelfth-order chemical absorption column.

ISSN:0020-7179    

DOI:10.1080/00207178208922603

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

This paper introduces a linear time invariant system analysis tool, the singular value sensitivity function, which can be used in conjunction with singular value analyses to provide more complete estimates of system feedback properties. An important feature of this tool is the ability to analyse the effect of simultaneous variations in several system parameters.

ISSN:0020-7179    

DOI:10.1080/00207178208922604

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Several approaches to estimating the parameters of a continuous-time model of a multivariable system from samples of input and output observations arc discussed. These include indirect methods where a discrete-time model is first obtained from the input-output data and then transformed into a continuous-time model, as well as direct methods where the continuous-time model is obtained straight from the samples of the observations. An example is used to compare the methods.

ISSN:0020-7179    

DOI:10.1080/00207178208922605

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

An arrangement of the differential-algebraic equations of feedback control systems is proposed to reduce the number of calculations required to obtain the time response repeatedly in the method of inequalities. The arrangement is chosen so as to preserve the sparsity of the system matrices and to use the fact that only the controller is changed at each repetition. It is shown that great economy in computation is possible by the use of this arrangement.

ISSN:0020-7179    

DOI:10.1080/00207178208922606

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

In this paper, a computer-aided method for reducing the order of a digital control system is developed. This is done by minimizing a weighted mean square error between the frequency responses of the reduced and the original systems. The method is demonstrated by a numerical example and the results are compared with those of the continued fractions method developed by Shin and Wu and the optimization method of model reduction developed by Luus.

ISSN:0020-7179    

DOI:10.1080/00207178208922607

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Optimal control of norm-invariant systems is discussed in relation to two constraints : (i) control constrained to a hypersphere ; and (ii) control constrained to a hyper-rectangle. In the case of the first (smooth) constraint set, it is well known that, for certain optimal control problems, the solutions have a particularly simple structure ; a generalization of the time-optimal regulator is given. In the case of the second (non-smooth) constraint set, it is shown that, for a particular optimal control problem, the solution is again of simple form and may be synthesized via switching hyperplanes, as illustrated in two examples of (a) controlled Euler equations and (b) a controlled harmonic oscillator.

ISSN:0020-7179    

DOI:10.1080/00207178208922608

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor