摘要:

The paper investigates the chaotic behaviour of nonlinear feedback systems. A heuristic model of this phenomenon is proposed and applied. Conditions for the existence and the location of chaotic motions are derived in terms of simple relations among the parameters of the system. Two examples show the application of the method and its approximation is discussed.

DOI:10.1049/ip-d.1991.0042

出版商:IEE    

年代:1991

数据来源: IET

摘要:

The paper presents a new direct model reference adaptive control algorithm for a class of large scale interconnected systems. It is assumed that the system is subjected to bounded disturbances and is characterised by unknown constant parameters which take values within a known bounded range. Conditions are determined under which the adaptive control law guarantees boundedness of the controller parameters and ensures asymptotic stability of the tracking error between the system and the model to a bounded residual set. Application of the algorithm to the problem of damping the electromechanical oscillations in multimachine power systems is also considered. A specific numerical example of a three-machine nine-bus system is presented to illustrate the results.

DOI:10.1049/ip-d.1991.0043

出版商:IEE    

年代:1991

数据来源: IET

摘要:

A systematic and conceptually simple algorithm is presented for the determination of the transfer function for two-dimensional generalised or singular systems. The method uses the discrete Fourier transform (DFT) and can easily be applied. The simplicity and efficiency of the algorithm are illustrated by two examples.

DOI:10.1049/ip-d.1991.0044

出版商:IEE    

年代:1991

数据来源: IET

摘要:

Using as an example a simple position control with narrow accuracy requirements, the paper makes a comparison of a number of design methods. It demonstrates that, by considering the phase-plane, simple piecewise-linear controllers can be designed to achieve excellent performance in competition with more sophisticated methods. Nonlinear suboptimal controllers are considered; it is shown that ‘pessimistic’ design can give substantial immunity to deflecting forces. The assertions are supported by simulations, and the performance is compared with that of time-optimal control.

DOI:10.1049/ip-d.1991.0045

出版商:IEE    

年代:1991

数据来源: IET

摘要:

The paper describes the use of the blackboard architecture for the traffic control of group automatic operation of elevators in a multistorey building. The performance of the elevator system is measured by two indicators: System Response Time and System Service Time. A blackboard system was implemented in Prolog and the opportunistic type of problem-solving offered by the blackboard architecture succeeded in obtaining a solution. Simulation results illustrating the operation of the blackboard system are presented.

DOI:10.1049/ip-d.1991.0046

出版商:IEE    

年代:1991

数据来源: IET

摘要:

Constrained receding-horizon predictive control (CRHPC) is intended for demanding control applications where conventional predictive control designs can fail. The idea behind CRHPC is to optimise a quadratic function over a ‘costing horizon’ subject to the condition that the output matches the reference value over a further constraint range. Theorems show that the method stabilises general linear plants (e.g. unstable, nonminimum-phase, dead-time). Simulation studies demonstrate good behaviour with even nearly unobservable systems (where generalised predictive control is ineffective) and that control-costing is a particularly effective tuning parameter.

DOI:10.1049/ip-d.1991.0047

出版商:IEE    

年代:1991

数据来源: IET

摘要:

The paper is concerned with transputer implementations of three forms of the Kalman filter algorithm. Two approaches to a concurrent realisation are considered, involving heuristic partitioning of the conventional sequential algorithm and proposing a new strategy for mapping the systolic array descriptions onto parallel processors. Real-time implementation results on transputer networks are presented and the relative performances evaluated in terms of speed, parallel processing efficiency and numerical accuracy for a test system. This attempts not only to quantify the performances of parallel Kalman filters but also to address the more general issues involved in mapping algorithms onto architectures.

DOI:10.1049/ip-d.1991.0048

出版商:IEE    

年代:1991

数据来源: IET

摘要:

The concept of extended linearisation for nonlinear control design yields control systems for which the linearisations have eigenvalues independent of the operating point. The computations of the procedure is complicated. There are systems where the parameterisation of the operating points by the input cannot be directly applied. A novel method of parameterisation of the operating point which overcomes these disadvantages is proposed. Its effectiveness is proved by application to the stabilisation of a synchronous generator, which is a problem of great importance in power systems control. The results are compared with conventional control using a linear pole-placing controller. The robustness of the proposed nonlinear control is also considered.

DOI:10.1049/ip-d.1991.0049

出版商:IEE    

年代:1991

数据来源: IET

摘要:

A state-space self-tuning LQG regulator is obtained. The algorithm differs from other state-space approaches since the controller and estimator are found by polynomial equations rather than matrix manipulation. The approach arises naturally from the Wiener theory of control, rather than the steady-state Kalman theory of other work. An example is given of the control of an open-loop, unstable and nonminimum phase system.

DOI:10.1049/ip-d.1991.0050

出版商:IEE    

年代:1991

数据来源: IET

摘要:

The development of an expert system in the domain of computer-aided control systems design is presented. An expert system has been developed and incorporated into an existing control systems design package called SROOT. The combined software is used to design linear single variable systems using the root locus techniques. The expert system provides software-based design expertise involving control theory, visual aspects of graphical outputs and engineering heuristics. Two new components for the expert system are introduced. These are the two types of facts used and a firing order unit. The former enables rules to be written in a generally-applicable format. The latter provides a systematic way of applying expertise. An overall design heuristic which supports the design of lead/lag compensators for the systems considered is introduced. A design example is given to exhibit the capability of the expert system.

DOI:10.1049/ip-d.1991.0051

出版商:IEE    

年代:1991

数据来源: IET