摘要:

Lie algebras and the Cartan decomposition are used to study the stability of ‘pseudo-linear’ systems of differential equations.

ISSN:0020-7179    

DOI:10.1080/00207179408921467

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

In this paper, a general interpolation formula is presented that yields the real rational solutions when the complex points are interpolated. The proposed interpolation formula includes the algorithms of Nevanlinna and Pick and of Dorato and Li as special cases. The results of this paper are based on the positive real interpolation theories developed by Youla and Saito.

ISSN:0020-7179    

DOI:10.1080/00207179408921468

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

AH∞self-tuning controller which is based on the generalizedH∞cost-function is described that includes robust design features. TheGH∞control law is simple to compute and is suitable for multivariable self-tuning control applications. The simplifications achieved in the controller structure which are necessary for use in self-tuning, depend upon the assumptions made on system and cost-weighting models. The cost-function weights are assumed to ensure a system matrix can be factorized into a particular form. The control law is coupled to an extended least squares identification algorithm. TheGH∞control law may be designed to be insensitive to unmodelled dynamics and the self-tuning action provides adaption to parametric uncertainty.

ISSN:0020-7179    

DOI:10.1080/00207179408921469

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Although previous papers have focused primarily on the functional mapping between an approximate reasoning algorithm and the neural network approach, here we are concerned mainly with structural mapping between those two paradigms. Our objective is to deal with three different but correlated issues, rule-base acquisition, computational representation, and reasoning, under a unified framework of CPN-based neural networks. In particular, we introduce a simple and systematic scheme capable of self-organizing and self-learning the required control knowledge in a real-time manner for a multivariable process. The starting point of the approach is to map structurally a simplified fuzzy control algorithm (SFCA) developed by the authors into a counterpropagation network (CPN) in such a way that the control knowledge is explicitly represented in the form of connection weights of the nets. Then, by extending original training algorithms at both the Kohonen and Grossberg layers into highly self-organized and completely unsupervised versions, the control rule-base, initially empty, is gradually self-constructed to satisfy the prespecified performance requirements. Finally, the approximate reasoning is carried out by replacing a winner-take-all competitive scheme with a soft matching cooperative strategy. The approach is very generic in the sense that, in principle, an arbitrary dimensional control rule-base can be constructed automatically to satisfy arbitrary desired but physically achievable performance requirements. The learning process involved is extremely fast owing to the simple network topology and the efficient learning algorithms. A problem of multivariable control of blood pressure has been studied as a demonstration example. Extensive simulations have been performed, aimed at investigating adapting, learning, and reasoning capabilities of the system with respect to a variety of situations in the sense of defined performance measures.

ISSN:0020-7179    

DOI:10.1080/00207179408921470

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The principle of matching is a concept of design that requires the objects of the design (the system and its environment) be matched. The main objective of a match is to ensure that the set of possible inputsP, which the environment imposes on the system, is a subset of the set of tolerable inputsT(those which are judged to produce an acceptable response from the system). In a recent paper, practical conditions for a match were presented when the set of possible inputsPis characterized by restrictions both on the input and the rate of change of the input, and the set of tolerable inputsTis characterized by bounds on the absolute supremum of the response of the system. In this paper, the use of one of these practical conditions is illustrated in the design of a vehicle speed control system, which is an improvement on a system designed in an earlier paper. Included here is an explanation as to why the practical conditions used in the earlier design cannot be used in this work, whereas the more recent conditions can be used.

ISSN:0020-7179    

DOI:10.1080/00207179408921471

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The authors present new filtering algorithms for uncertain-stochastic dynamic systems, which are optimal in the sense of a minimax-stochastic criterion. These algorithms allow us to estimate the state vector of dynamic systems given incompletea prioriinformation about the system characteristics and using observations of the state and input signals. The filtering algorithm is used to construct an optimal two-filter smoothing algorithm for pure uncertain dynamic systems. These algorithms are numerically tested. Results are compared with the results of Kalman filtering and smoothing in the case of complete information about the input signal characteristics.

ISSN:0020-7179    

DOI:10.1080/00207179408921472

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The existing exact model matching (EMM) makes it possible for a plant output to exactly follow the reference model output, if no disturbance is applied to the plant, i.e. EMM has perfect tracking performance. EMM does not however, suppress the disturbance effect positively, and hence, the specification on regulating performance will not be satisfied on certain occasions. Disturbances, as described by any deterministic or stochastic formula, are not considered here; the only assumption is that they are bounded and vary slowly with time. In this paper, a new method to synthesize a disturbance predictor, as well as an EMM design method to suppress the disturbance effect using the prediction, is developed. The same control system is also effective to suppress the plant perturbation such as parameter variation, nonlinearity and unmodelled dynamics.

ISSN:0020-7179    

DOI:10.1080/00207179408921473

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

In this paper we analyse the stability robustness of linear continuous-time and discrete-time systems with structured time-varying uncertainties. The system to be controlled is described by the usual state-space formulation but includes time-varying uncertainties. The first new robust stability sufficient condition we have derived in this paper may become the necessary and sufficient condition of system stability in some situations. The second new condition is always less conservative than the sufficient condition recently proposed by Sobelet al., (1989). The third new condition, using the similarity transformation, provides the possibility of getting even less conservative results. In deriving these new conditions we also present some new lemmas which are valuable in related research. The results are extended to linear discrete-time systems and some illustrative examples are given.

ISSN:0020-7179    

DOI:10.1080/00207179408921474

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

H∞-problems with state feedback are considered for time-varying discrete systems. First quadratic games related to H∞-problems are studied. A necessary and sufficient condition for the existence of a stabilizing controller, such that the norm of the operator from the disturbance to the output is less than a prescribed number, is given in terms of a Riccati equation.

ISSN:0020-7179    

DOI:10.1080/00207179408921475

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor