摘要:

The paper is devoted to the study of robust strict positive realness design of interval systems, i.e. considering the question of designing a single controller which both robustly stabilizes an interval denominator system by unity feedback and makes the closed-loop transfer function robustly strictly positive real. By establishing a new computationally checkable criterion for the strict positive realness of a rational function, the extreme point result for a class of interval denominator systems is obtained, which significantly simplies the controller design procedure.

ISSN:0020-7721    

DOI:10.1080/00207729408949295

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Model reference adaptive identifiers (MRAI) are designed with the assumption that the reference model M¯ is strict positive real (SPR). The properties of MRAI with gradient algorithms have been well studied. In this paper we analyse the MRAI with least-square (LS) algorithms. It is found that a sufficient condition for the system stability is that M¯ − ½ is SPR. A generic averaging technique is developed for the adaptive systems with periodic inputs. Then averaged systems of MRAI with the LS algorithm are formed. Simulation studies illustrate the properties of MRAI and verify the validity of the averaging approximation.

ISSN:0020-7721    

DOI:10.1080/00207729408949296

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Cross-couplings are present in all the generators belonging to interconnected power systems. As is well known, the presence of these couplings is one of the major sources of voltage variations and rotor oscillations in the generators belonging to the system. To solve this problem a geometric graph-theoretic approach is proposed by which a state feedback decoupling controller is derived. The proposed controller can also assure a desired location to all the critical eigenvalues of the decoupled closed-loop system, so that the improvement of the dynamic performance of each generator is guaranteed. The capability and usefulness of the proposed technique are illustrated by considering a 14-generator 34-busbar test system.

ISSN:0020-7721    

DOI:10.1080/00207729408949297

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A novel approach to decentralized state estimation in a large-scale interconnected system is proposed. The method assumes a known model for the local subsystem only, and therefore is suitable when the other subsystem models and the interaction matrices are partially or totally unknown. An innovation representation suitable for decentralized subsystem state estimation is derived. The state estimation problem is then solved through the parametric identification of the innovation representation. The identification algorithm is based upon a pseudo-linear regression (PLR) principle that attempts minimization of the innovation variances.

ISSN:0020-7721    

DOI:10.1080/00207729408949298

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Thermoluminescence dating has attracted the attention of geology and archaeology researchers as a new method. This method requires a heating device to raise the temperature of the specimens at an exact rate. This paper describes the design method of a control system that can achieve this goal. This control system lends to be unstable because of the existence of the parameter perturbation and dead time. In this paper, the perturbation and dead time are treated as perturbations of a nominal plant regarded as a first-order lag time system. Improvement of tracking characteristics in the low-frequency domain and robust stability in the high-frequency domain of the control system are achieved by using the solution of the mixed-sensitivity problem that is a kind of H∞control theory. Experiments verify the effectiveness of this method.

ISSN:0020-7721    

DOI:10.1080/00207729408949299

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A new approach to find an accurate and realistic estimate of the completion time of PERT type network projects is presented. The project completion times calculated by the new method are compared with those of the standard textbook PERT method against bench mark values supplied by a simulation program. Beta distribution with four parameters is assumed for each activity. The four moments of the paths are calculated and Schmeiser-Deutsch distribution is fitted to each path. The project completion time is computed as the maximum of n stochastic variables represented by each path length. The project completion times found by this new technique are more accurate and much closer to the simulated values than those of PERT values. The significance is more prominent in cases where there are multiple paths with near equal lengths. The results may have practical applications in project management and overcome the perennial problem of ‘late projects’.

ISSN:0020-7721    

DOI:10.1080/00207729408949300

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A systematic theory is given for the output-sliding control (OSC)of linear time-invariant systems with concentrated parameters. It is shown that the output tracking error can be guaranteed to converge to zero with an exponential rate. The closed-loop eigenvalues in the sliding mode can be effectively assigned by the use of OSC. System robustness is achieved with respect to a larger class of disturbances and parameter variations than that by the use of conventional state-sliding control (SSC). Supporting techniques are given for the implementation of the theory. An illustrative example is studied to show the superiority of OSC over SSC.

ISSN:0020-7721    

DOI:10.1080/00207729408949301

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A new method for the approximation of bilinear systems is proposed. The reduction scheme applies to both stable and unstable bilinear systems. The technique uses generalized input normal representations to retain the dominant part of the original system. The algorithm is evaluated on a synchronous induction generator and is shown to lead to acceptable reduced approximations of the original system. A frequency weighting is also introduced in the reduction scheme to further improve the approximation.

ISSN:0020-7721    

DOI:10.1080/00207729408949302

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This paper presents a queueing model for a single-stage manufacturing system. The arrival process at the facility is the superposition of the unco-ordinated arrival processes of various items and is represented by a compound Poisson process. It is shown that the expected waiting time of an average unit depends on the expected batch size and the batch size variability, whereas the expected batch completion time depends only on the expected batch size. The optimal processessing rate is also derived as a function of the appropriate cost factors. A lot sizing model is developed which provides the optimal batch size as a function of inventory-related costs. Finally, it is demonstrated through simulation that the Poisson arrival approximation is less severe when the item mix is composed of a large number of items.

ISSN:0020-7721    

DOI:10.1080/00207729408949303

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Formulae are given for the characterization of second-order system transients obtained from measurements on the dynamical system's response to a step function input. The derived formulae are used to derive second-order models of high-order plants.

ISSN:0020-7721    

DOI:10.1080/00207729408949304

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor