摘要:

Previous work of the authors on the use of overlapping parametrizations of finite-difference equations in the identification of multivariable systems is continued. By considering numerical and accuracy issues, a two-stage, IV-based, joint parametrization-selection and parameter-estimation scheme is proposed. The parametrization selection seeks to ensure that the estimation problems are numerically well conditioned, whereas the second stage ensures statistical efficiency in certain circumstances.

ISSN:0020-7179    

DOI:10.1080/00207178708933905

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A growing trend in the computer-aided design of classical control systems is to formulate the design problem so that it is soluble by numerical (mathematical programming) methods. This paper derives criteria for assessing the suitability of such formulations, proposes new formulations and discusses the implications of the new formulations for the development of control theory.

ISSN:0020-7179    

DOI:10.1080/00207178708933906

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This paper investigates the relationship between stabilizability and certain notions of controllability for a class of uncertain linear systems containing time-varying unknown-but-bounded uncertain parameters. The paper introduces a notion of controllability invariance. Roughly speaking, an uncertain system is controllability invariant if it is controllable (in the usual sense) for each fixed value of the uncertain parameters. The paper describes a class of uncertain systems for which controllability invariance implies stabilizability.

ISSN:0020-7179    

DOI:10.1080/00207178708933907

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The application of a minimum variance self-tuning approach to the load frequency control of a multi-area power system is presented in this paper. It is shown that for slow sampling rates the basic minimum variance control can function, but as the sampling rate is increased in order to cover the required bandwidth, the controller fails. Explanations are given for these characteristics and it is shown how these difficulties can be removed by employing a generalized minimum variance controller.

ISSN:0020-7179    

DOI:10.1080/00207178708933908

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This paper presents a new method of hierarchical control for large-scale time-varying systems via block pulse transformation. The resulting solutions are piecewise constant with minimal mean-square error. The proposed method is simple and computationally advantageous. A numerical example is given to compare the solutions obtained by the hierarchically recursive method with those obtained by the globally recursive method.

ISSN:0020-7179    

DOI:10.1080/00207178708933909

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A non-linear system Σ has a right fraction representation if it can be represented as Σ = PQ−1, where P and Q are stable systems, and it has a left fraction representation if it can be represented as Σ = G−1T, where G and T are stable systems. We develop here a theory of right and of left fraction representations for discrete-time non-linear systems with bounded input sequences. We indicate the connection between fraction representations and the stabilization problem for non-linear systems.

ISSN:0020-7179    

DOI:10.1080/00207178708933910

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This note presents an alternative formulation to the use of unity rank output feedback for a multi-input and multi-output dynamic system whose output includes an additional input term. This sort of dynamic system is seen in servomechanisms and in singularly perturbed systems. The proposed method does not require any generalized inverses.

ISSN:0020-7179    

DOI:10.1080/00207178708933911

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A method is outlined for designing Smith predictor controllers that provide robust performance despite real parameter uncertainties in the process model. Insight into the design process is gained by viewing the Smith predictor from the perspective of internal model control. Performance requirements are written in terms of a frequency-domain weight restricting the magnitude of the closed-loop sensitivity function. A general method for approximating multiple parameter uncertainties by a single multiplicative uncertainty is developed—an exact bound is derived for the magnitude of multiplicative uncertainty used to approximate simultaneous uncertainties in process gain, time-constant, and time-delay. Three different tuning methods are demonstrated; each is applied to a wide range of parameter uncertainties in a first-order with time-delay model. The first tuning method locates loop transfer-function uncertainty regions to test for robust performance—real parameter uncertainties are considered exactly. The second tuning method approximates real parameter uncertainties by multiplicative uncertainty and uses structured singular value analysis to guarantee robust performance. The third is a ‘quick design’ method that considers the unit magnitude crossing of the multiplicative uncertainty. Finally, the Smith predictor controller is compared with the structured-singular-value-optimal controller.

ISSN:0020-7179    

DOI:10.1080/00207178708933912

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The problem of model reduction in the context of control system design is investigated. Starting from closed-loop objectives (H2,H∞, and μ), equivalent weighted open-loop plant and controller reduction problems are developed. The control-relevant weight function incorporates explicitly all the important characteristics of the control problem, such as the setpoint/disturbance spectrum and the designer requirements for the sensitivity/complementary sensitivity functions, Furthermore, these control-relevant reduction problems are complemented with validation procedures that indicate rigorously the effects of the reduction problem on the desired performance objectives. A simple algorithm that uses standard regression routines is presented to solve these problems.

ISSN:0020-7179    

DOI:10.1080/00207178708933913

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The property is studied of stabilizing a polynomial control system to a subspace of its state space using a continuous feedback law. A sufficient condition for the output stabilizability problem is also included.

ISSN:0020-7179    

DOI:10.1080/00207178708933914

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor