摘要:

A novel extension of the Nyquist array methods to accommodate for system uncertainties is presented. The concept of robust diagonal dominance is introduced ; necessary and sufficient conditions for robust stability are developed and the issue of robust performance is addressed. Two examples are given to demonstrate the power of the method for analysis and design of robust feedback control systems.

ISSN:0020-7179    

DOI:10.1080/00207178408933296

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

Consider the single-input non-linear systemx=f(x, u). It has been shown that, under mild conditions, there exist transformationsz=T[x),v=S(x, u) such that, in the z-space, the linear tangent model is independent of the operating point. A constructive procedure to obtain the above transformations is described. This new method is computationally attractive and effective in many practical cases.

ISSN:0020-7179    

DOI:10.1080/00207178408933297

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

This paper discusses the problem of improving the behaviour in adaptive control schemes during the adaptation transient. The key idea of the method consists of the use of adaptive sampling taking the tracking (or regulation) error between the reference model and the controlled system outputs as the signal to be adapted. The adaptation algorithms used are of the same type as those commonly used for the usual case of constant sampling. Several simulated examples corroborate the practical aspects of the method.

ISSN:0020-7179    

DOI:10.1080/00207178408933298

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The problem of finding the stability range of a scalar gain (or parameter) is a simple one for multivariable feedback systems. We propose an algebraic procedure for the relative stability range using the so-called ’ critical constraint ’. This method is simpler than the frequency domain approach and compared favourably with a recently proposed approach.

ISSN:0020-7179    

DOI:10.1080/00207178408933299

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The strucxpects of the rationxr spacesxc,xfwherexcis the columxof the transfer function matrix G(s) andxf, is the space associated with right matrix fracxcriptions of G(s), are investigated. Forxfgcanonixqb;s] Grassmgesentaxg(xc) andg(xf) arxd, and are shownxmplete basis free invariants forxcandxfrespectively. The almost zeros (AZ) and almost decoupling zeros (ADZ) of G(s)gdefinexlocal minima of a normgn defixg(xc) andg(xf) respectively. The computation, and certain aspects of the distribution in the complex plane of AZs and ADZs are examined. The role of AZs and ADZs in the determinantal zero and pole assignment problems respectively is examined next. Two important families of systems are defined : the strongly zero non-assignable (SZNA) and the strongly pole non-assignable (SPNA) systems. For SZNA and SPNA systems minimal radius discs Deme[z,Reme(z)] and Demf[zb centred at an AZ and ADZ respectively are defined. It is shown that Deme[Reme(z)] contains at least one zero of all systems derived from G(s) under squaring down and Demf[z,Remf(z)] contains at least one pole of all systems derived from G(s) under constant output feedback. A criterion for determining upper bounds forReme(z) andRemf(z)is given. These results show that AZs act as ‘ nearly fixed ’ zeros under squaring down, and that ADZs act as ‘ nearly fixed ’ closed-loop poles under constant output feedback. Systems which under constant post and feedback compensation have their zeros and poles, respectively, ‘ trapped ’ in the right-half complex plane are examined and a criterion for testing such properties is given. This work reveals the AZs and ADZs as ‘ strong ’ invariants characterizing families of systems derived from G(s) and not just the particular minimal system defined by G(s).

ISSN:0020-7179    

DOI:10.1080/00207178408933300

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

We study the multiple time-scale structure of linear systems of the form

ISSN:0020-7179    

DOI:10.1080/00207178408933301

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

This paper considers the influence of the statistics of a scalar continuous-time system with white stochastic parameters on the statistics, the correlation and the stabilizability of the corresponding scalar equivalent discrete-time system. By means of numerical examples some insight into the behaviour of the equivalent discrete-time system is given. Furthermore these examples illustrate the crucial influence of the correlation between the state- and control-dependent noise of the continuous-time system on the stabilizability of the equivalent discrete-time system.

ISSN:0020-7179    

DOI:10.1080/00207178408933302

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

In this paper necessary and sufficient conditions are given for the existence of a dead-beat observer for a linear periodic discrete-time system subject to immeasurable periodic disturbances. The conditions express, in terms of the disturbed system, the reconstructibility of the augmented system obtained by connecting the former with the disturbance generator. A synthesis procedure of the observer is also provided.

ISSN:0020-7179    

DOI:10.1080/00207178408933303

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

The measured convergence rates of several algorithms belonging to the class of 1 gradient methods in function space ’ are compared. The steepest descent, conjugate gradient and quasi-Newton algorithms, and the effect of different types of linear search routine and initial guess parameters on their convergence rates, are considered. It is concluded that conjugate gradient methods do offer significant advantages, even for non-linear system models and bounded controls.

ISSN:0020-7179    

DOI:10.1080/00207178408933304

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor

摘要:

A new method is proposed for the determination of the output sensitivity function. This method is based on the idea of using orthogonal functions and has the distinct advantage that it reduces the problem of determining the output sensitivity function to that of solving linear algebraic equations. The approach is straightforward and appears to be computationally simpler than known techniques.

ISSN:0020-7179    

DOI:10.1080/00207178408933305

出版商:Taylor & Francis Group    

年代:1984

数据来源: Taylor