摘要:

It is known that the describing function method can fail to predict limit cycles which do in fact exist. We wish to draw attention to a different mode of failure, where the method predicts limit cycles which do not exist. A surprising feature of the example we give is that the linear part of the system has excellent low-pass properties, unlike the linear parts used in examples of the other failure mode.

ISSN:0020-7179    

DOI:10.1080/00207177708928526

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

This paper introduces the connection matrix as a generalization of the transmittance matrix approach used in signal flow-graph analysis. The connection matrix is shown to be a simple and computationally efficient way to describe composite systems formed from an interconnection of single-variable and multi-variable subsystems. The approach allows system descriptions in state-space form, transfer-function form, and system-matrix form, and allows the transmissions between arbitrarily nominated sets of inputs and outputs to be readily determined.

ISSN:0020-7179    

DOI:10.1080/00207177708928527

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

A practical design procedure of an unknown input observer for a class of multi-input/output systems is presented, the fixed poles of this observer are shown to be given by the zeros of the McMillan form.

ISSN:0020-7179    

DOI:10.1080/00207177708928528

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

A new concept, undisturbability, is formally defined and related to the concepts of uncontrollability and structural controllability. Necessary and sufficient conditions for a system to have undisturbable state or output variables are expressed in terms of the structure of the coefficient matrices in the state-space model and the structure of the eigenvector matrix. These results and an eigenvector/eigenvalue assignment algorithm (Srinathkumar and Rhoten 1975, Shahet al. 1975) provide the basis of a design procedure for synthesizing multivariable controllers which achieve disturbance localization.

ISSN:0020-7179    

DOI:10.1080/00207177708928529

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

A method is presented for designing constant multivariable feedback controllers that make selected closed-loop eigenvaluesinvarianttounknownperturbations ofarbitrarymagnitude in system parameters. The sufficient conditions for eigenvalue invariance are expressed in terms of the structure of the closed-loop system matrices, and a numerical example is included to show how eigenvalue/eigenvector assignment techniques can be used to produce the desired eigenvector structure and thereby, eigenvalue invariance.

ISSN:0020-7179    

DOI:10.1080/00207177708928530

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The problem of estimating unknown parameters of a discrete-time noisy dynamical system is solved by minimizing the overage of norms of an ‘ innovation ’ sequence. It is shown that the estimates obtained are consistent under a certain sufficient condition. This condition is given in explicit verifiable form.

ISSN:0020-7179    

DOI:10.1080/00207177708928531

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The stability of the periodic solutions of a particular non-linear differential equation of third order is discussed in terms of the asymptotic stability of the corresponding variational equation and, thereby, in terms of the characteristic exponents of this equation. A method, due to Cesari, is used to evaluate the characteristic exponents and thus the boundaries of asymptotic stability. Taking the solution to have, in the first approximation, an amplitudeFand frequency ω, it is shown that one of the asymptotic stability boundaries corresponds to the locus of vertical tangents of the frequency response curves in the ω,Fplane. This result is similar in character to, and a modest generalization of, the well-known stability criterion associated with Duffing's equation.

ISSN:0020-7179    

DOI:10.1080/00207177708928532

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

High frequency signal injection (dither) has found applications in control and stabilization, adaptive systems, identification and quantization. A discussion of typical uses is given and analyses are presented using the concept of equivalent non-linearity.

ISSN:0020-7179    

DOI:10.1080/00207177708928533

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The peculiar identification problems which arise in the study of feedback systems often require the use of an external reference signal. This paper discusses the properties of non-parametric and parametric closed-loop identification schemes which rely upon such a signal. For the non-parametric case the statistical properties of an unbiased frequency-response estimator are developed and compared with the conventional estimator. The use of reference signals in parametric estimation is discussed in a way which enables the correct structure of a feedback system to be unambiguously determined.

ISSN:0020-7179    

DOI:10.1080/00207177708928534

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

In this paper the optimal approximation of a high-order system, subject to polynomial inputs, is investigated.

ISSN:0020-7179    

DOI:10.1080/00207177708928535

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor