摘要:

This article presents a differential geometric approach for the design of sliding modes in non-linear variable-structure feedback systems. Coordinate-free characterizations of local existence conditions for sliding regimes, and a geometric reformulation of some of its most salient features are presented. The approach uses basic notions from differential geometry involving vector fields, distributions and 1-forms. Both single- and multiple-input cases are treated with some illustrative examples.

ISSN:0020-7179    

DOI:10.1080/00207178808906256

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A new sufficient condition for robust stabilization of SISO discrete-time feedback systems with both non-linear (or linear) time-varying uncertainties and constrained actuators is derived. In this paper, neither the plant nor the controller has to be restricted to the stable or minimum-phase case. The necessary and sufficient condition for solvability of a stabilizer satisfying such a robust constraint is also introduced. The optimal H∞-norm theory is employed to achieve the maximum robustness to tolerate the uncertainties via constrained control. Finally, a design algorithm is proposed to specify adequate parameters in the compensator to satisfy the criterion of optimal robustness and an example with computer simulation is given to illustrate the results.

ISSN:0020-7179    

DOI:10.1080/00207178808906257

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A general formula, originally to find the scalar partial fraction expansion (PFE) of a (scalar) rational function and the matrix-PFE of a rational transfer matrix, is generalized to find the block-PFE of a right coprime matrix fraction description (MFD) with simple and/or repeated block poles. This formula expresses the block residues explicitly in terms of the coefficient matrices of the numerator and the denominator matrix polynomials, and the left solvents of the denominator matrix polynomial. It is therefore straightforward and easy to apply, as compared with the existing methods.

ISSN:0020-7179    

DOI:10.1080/00207178808906258

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A digital controller design technique must yield all controller parameters, including the sampling rate 1/T, as functions of (continuous-time) specifications. It will be shown that, under certain conditions, sampling is modelled by a continuous-time (1 -sT/2) in the loop transfer function.

ISSN:0020-7179    

DOI:10.1080/00207178808906259

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Using simple transformations of the block-diagram a criterion is derived for Instability (Zames 1964, 1966a, b) of conventional feedback systems with the non-linearity f(˙) satisfying an integral condition, namely,where β is a positive constant, It is shown that the criterion is more general than the Popov criterion (Popov 1962) in that a sector condition need not be satisfied and the non-linearity can lie in all the four quadrants. This is because the criterion fully exploits the characteristics of the open-loop transfer-function G(s). A more general case of the criterion with the non-linearity satisfying an integral plus a slope restriction is also presented.

ISSN:0020-7179    

DOI:10.1080/00207178808906260

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The problem of obtaining all stochastic realizations of a discrete-time non stalionary stochastic process defined on the set of integers is considered. The structure of the set of all covariances of the states of such realizations is studied. Special attention is paid to the minimum and maximum elements of this set. Finally, a non-Riccati-type algorithm—which does not require solution of a matrix Riccati equation—to generate (wide-sense) stochastic realizations is presented.

ISSN:0020-7179    

DOI:10.1080/00207178808906261

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

In recent years, many studies have been reported on methods of examining the problems of the robustness of multi-input and multi-output systems in the frequency domain using the singular value technique. However, since the conventional criteria have been derived as sufficient conditions for stability or sensitivity reduction, they are more than sufficient (or so-called conservative conditions) and therefore they have the disadvantage that they cannot be used for the evaluation of stability and/or sensitivity reduction. In this paper we propose new criteria for robust stability and sensitivity reduction with reduced conservatism which utilize equivalent systems with the same transfer function as that of the plant. In order to illustrate the effectiveness of these criteria, examples of the longitudinal and lateral motion of aircraft are analysed by both the conventional and the proposed methods, and the results are compared to show the advantage of the proposed method.

ISSN:0020-7179    

DOI:10.1080/00207178808906262

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A discrete-time, linear, time-invariant control system with a fixed time delay in the feedback loop is considered. We investigate the problem of feedback stabilization and present some general criteria. Simple necessary and sufficient conditions for stabilization, which take the form of algebraic inequalities involving the system parameters, are developed for time delays whose values do not exceed 2, as well as for one-dimensional systems with an arbitrary time delay.

ISSN:0020-7179    

DOI:10.1080/00207178808906263

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A new method for the design of stabilizing controllers for multivariable bilinear systems is presented. The design method is based on a Liapunov stability theorem and the solution of a Liapunov equation. The resulting non-linear control globally asymptotically stabilizes the closed-loop system and minimizes a generalized quadratic performance index. The effect of the weighting matrices on the closed-loop response is analysed. Simulation results demonstrate that the new design technique provides better control than linear feedback. Moreover, the linear feedback can destabilize the closed-loop system depending on the initial conditions, whereas the new control strategy results in global asymptotic stability.

ISSN:0020-7179    

DOI:10.1080/00207178808906264

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A new algorithm based on pole-assignment considerations for linear time-invariant m-input p-output systems by means of static output feedback is presented for the case in which the number of inputs m and the number of outputspare less than the order of the system n. This algorithm determines the output-feedback matrix required to assign max (p, m) - 1 poles, and simultaneously calculates the coefficients of the residual polynomial, the roots of which are the remaining unassigned poles. The root-locus method is used to find an appropriate feedback gain to provide acceptable locations for the unassigned poles. Some numerical examples are provided to illustrate this method.

ISSN:0020-7179    

DOI:10.1080/00207178808906265

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor