摘要:

The weighted residual concept of ordinary differential equation solutions is extended to the two problems of continuous linear system identification and model reduction. Although continuous system dynamics are classically described in terms of the system ordinary differential equation, an equivalent integral equation description exists and it is this latter equation which is used as the basis of the various identification and model reduction techniques. Several individual approaches within the broad class of weighted residual approaches are detailed and a number of numerical examples are presented to illustrate the application of such schemes.

ISSN:0020-7721    

DOI:10.1080/00207728908910150

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A digital controller for the regulation of glucose in the metabolic system was achieved through an open-loop scheme in which the continuous measurement of the actual glucose concentration is not required, assuming the model is sufficiently accurate and the controller is robust. The analysis of individual human subjects has shown great differences in their responses to glucose infusion. Consequently there were also distinct differences in the optimized controller parameters. In principle, such differences lead to significant differences in the closed-loop dynamics. A fourth-order digital model was obtained from the state differential equations which represent the system metabolism. The sample time was chosen sufficiently large to suit such a slow system. The zeros of the controller were selected to match the undesired complex poles of the metabolic system and the controller gain was determined using the root locus portrait. A set of well-behaved performances together with their corresponding internal states were obtained with variable overshoot. The controller was shown to be robust and the results obtained suggest the application of the developed open-loop scheme for glucoregulation in vivo.

ISSN:0020-7721    

DOI:10.1080/00207728908910151

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The concept of solving the linear programming problem with non-deterministic constraints is presented in this paper. It is assumed that the right-hand sides of the constraints are fuzzy numbers, and the problem is solved for their mean values. Furthermore, a fuzzy solution of the problem is specified for the optimal basis of the linear programming problem with mean values. A solution feasibility measure is introduced. When the measure is too small, another feasible solution of the problem for the mean values is chosen, which is non-optimal and which corrects the feasibility of the fuzzy problem with simultaneous deterioration of the goal function value.

ISSN:0020-7721    

DOI:10.1080/00207728908910152

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Three non-symmetrical positive-definite functions that generate non-symmetrical domains of Rnare proposed as candidate Lyapunov functions for discrete-time free linear systems. Three sufficient conditions are given in R2nfor these functions to become Lyapunov functions. The generated non-symmetrical domains are the stability domains for the class of dynamical discrete-time free linear systems that satisfy such conditions.

ISSN:0020-7721    

DOI:10.1080/00207728908910153

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Various model forms for the on-line identification of multi-input multi-output (MIMO) stochastic dynamic systems are reviewed. These models are the transfer function matrix, input-output difference equation, state-space representation, and decomposition form. The number of parameters to be identified and the structural parameters required to characterize each model are tested and compared. Results show that the decomposition form is very powerful for solving structure and parameter estimation problems of MIMO systems.

ISSN:0020-7721    

DOI:10.1080/00207728908910154

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The robustness of a pole-zero placement adaptive control algorithm in the presence of unmodelled dynamics and bounded external disturbances is studied. The algorithm is designed based on the reduced-order plant, which is assumed to be stable, but it does not necessarily have minimum phase. The overall plant is assumed to be stable, but it may have non-minimum phase. By using a normalizing signal and a projection in the adaptive law, a condition for stability is derived. The extra a priori information required is that bounds on the unknown plant parameters are known.

ISSN:0020-7721    

DOI:10.1080/00207728908910155

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Recursive estimators for utilizing new information to update or revise estimates of the parameters of an economic model are derived. The forthcoming information includes new data anda prioriprobabilistic information about changes, if any, occurring in the parameters of the estimated economic model over time. Such recursive methods are likely to prove useful to economists in a number of ways, such as the following: first, they can be used to develop tests for variation in structural coefficients over time; second, they enable tracking the parameters of time-varying economic systems; third, they admit the possibility of proceeding with the gathering of observed data until a specified accuracy of the parameters is achieved; and finally, they can play an important role in adaptive learning, forecasting and control. This paper examines recursive estimation in the context of both multiple equation as well as simultaneous equation models.

ISSN:0020-7721    

DOI:10.1080/00207728908910156

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The problem of obtaining a reduced-order model is considered for an interconnected high-order system which is composed of several subsystems. For such systems, retaining the internal structure of the original system in a reduced-order model is quite important from an engineering point of view. Of course the most desirable solution to the problem would be to derive an algorithm for constructing a reduced-order model under a single criterion, but unfortunately such an approach has not been found yet. Instead, we proceed to approximate each subsystem by reduced-order models and combine the results. In this case the following questions arise. (a) Does the reduced-order model obtained as above preserve the stability property under the assumption that the original system is stable? If not always, under what conditions? (b) How does the reduced-order model approximate the input-output characteristics of the original system? The present work answers these questions and the validity of the proposed method is pointed out via a numerical simulation.

ISSN:0020-7721    

DOI:10.1080/00207728908910157

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Within the context of non-linear variable-structure controlled systems, a general geometric characterization is introduced for the global existence of sliding motions on compact manifolds. As a necessary condition for the existence of global sliding motions, sign conditions are derived for the volume integrals of the divergence of the available feedback controlled vector fields. The ideal sliding dynamics are characterized in terms of a volume preserving flow or, equivalently, by a total zero-divergence smoothly controlled vector field. Several illustrative examples are given throughout the article.

ISSN:0020-7721    

DOI:10.1080/00207728908910158

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A numerical calculation technique for computing bifurcation values of interconnected dynamical systems is presented. The technique is based on continuation methods in which the bifurcation value of interconnected dynamical systems can be calculated from the bifurcation value of a subsystem using a set of coupled differential equations. As an example, the value of the Hopf bifurcation of an interconnected dynamical system is calculated.

ISSN:0020-7721    

DOI:10.1080/00207728908910159

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor