摘要:

The paper presents multistage decomposition of a high-gain feedback system as applied to a multimachine power system. Multitime scale decomposition is carried out by performing two time scale decomposition repetitively, in several stages. The decomposition leads to one slow system and several fast systems of different time scales. From the separate slow and fast system controllers, a composite stabilising controller is constructed by backward recursion and is implemented on the multimachine power system.

DOI:10.1049/ip-d.1993.0038

出版商:IEE    

年代:1993

数据来源: IET

摘要:

A simple and noniterative procedure for the computation of the exact value of the infimum in the singularH∞-optimisation problem is presented, as a continuation of our earlier work. Our problem formulation is general and we do not place any restrictions in the finite and infinite zero structures of the system, and the direct feed-through terms between the control input and the controlled output variables, and between the disturbance input and the measurement output variables. Our method is applicable to a class of singularH∞-optimisation problems for which the transfer functions from the control input to the controlled output and from the disturbance input to the measurement output satisfy certain geometric conditions. In particular, the paper extends the result of earlier work by allowing these two transfer functions to have invariant zeros on thejω-axis.

DOI:10.1049/ip-d.1993.0039

出版商:IEE    

年代:1993

数据来源: IET

摘要:

The paper deals with the distributed parameter systems described by coupled partial differential equations with singular matrix coefficients. Initial-boundary-value problems are considered in the light of both singular 1d systems theory and the Fourier approach to distributed parameter systems. The method presented in this paper gives the possibility of determining acceptable initial-boundary conditions. An illustrative example is given.

DOI:10.1049/ip-d.1993.0040

出版商:IEE    

年代:1993

数据来源: IET

摘要:

A recursive algorithm for designing an optimal modal controller is presented for the case of discrete MIMO systems. A basic method is developed, followed by an aggregative procedure which gives a computational simplicity. The state weighting matrix in the quadratic performance criterion and the feedback gain matrix are calculated without solving the algebraic matrix Riccati equation. At the same time the eigenspectrum of the closed-loop system is placed at some predefined location. The case of assigning real and distinct poles is developed entirely and is illustrated with a numerical example.

DOI:10.1049/ip-d.1993.0041

出版商:IEE    

年代:1993

数据来源: IET

摘要:

The paper is concerned with the application of reinforcement learning techniques to the stochastic control problem, and in particular presents a method based on learning automata for designing controllers for the control of unknown complex dynamic systems. The work is focused on the design of a learning automaton using subsets of control actions to reduce the number of actions during a learning procedure. The subsets of actions can be expanded or contracted according to action probabilities which are reset from time to time so as to achieve a global selection over the action set. Two reinforcement schemes have been investigated alongside the variable subsets of control actions. A reference performance index and an approach to quantification and normalisation of the performance index are proposed in association with the two schemes to evaluate environment responases during the learning procedure. The method has been used to achieve learning control for an unknown nonlinear turbo-generator system.

DOI:10.1049/ip-d.1993.0042

出版商:IEE    

年代:1993

数据来源: IET

摘要:

The work compares four recently proposed on-line methods of identification and controller tuning when the extreme points of the closed-loop response are either accurately known or subject to error. It is shown that Chen's and Lee's methods are relatively robust, with Chen's method giving slightly better estimates of process ultimate data. The method of Jutan and Rodriguez gives acceptable results and Yuwana and Seborg's method is the least acceptable. The work underscores the need to use high feedback gain during identification when experimental data are poor.

DOI:10.1049/ip-d.1993.0043

出版商:IEE    

年代:1993

数据来源: IET

摘要:

A PID autotuning algorithm based on relay feedback has the capability of exploring different points of the process frequency response before performing the actual tuning procedure. In addition, the algorithm minimises the amount ofa prioriinformation required on the process; in fact, the user is only asked to specify the minimum phase margin required for the closed-loop system. Some experimental results, obtained by laboratory simulation, are also presented.

DOI:10.1049/ip-d.1993.0044

出版商:IEE    

年代:1993

数据来源: IET

摘要:

One way to obtain a neighbouring feedback law for a time-delayed optimal control problem is to first transform it into a ‘standard’ optimisation problem. That is one without terms having a time-delayed argument. To this end, I use a Padé approximation to determine a differential relation fory(t), an augmented state that representsx(t−τ). The time-delayed optimisation problem can then be rewritten in terms of an augmented state vector consisting of both the physical statex(t) and the delayed statey(t). Once reformulated, one may use to advantage existing well-developed techniques such as the backward sweep method to obtain the neighbouring feedback law. Results obtained from two examples show good agreement between the exact results and those predicted by the feedback law for small variations in both the initial condition and a system parameter.

DOI:10.1049/ip-d.1993.0045

出版商:IEE    

年代:1993

数据来源: IET

摘要:

A new algorithm for model reduction of SISO linear continuous systems is proposed. It is based on the weighted impulse response Gramians. The reduction algorithm yields a family of stable reduced order models for different weighting factors in the weighted impulse response Gramian. The model corresponding to the weight of zero, matches the impulse response norm of the original system and its derivatives exactly. The method is illustrated by a numerical example and is compared with well known model reduction techniques.

DOI:10.1049/ip-d.1993.0046

出版商:IEE    

年代:1993

数据来源: IET

摘要:

The linear-quadratic-Gaussian (LQG) embedding approach for solving theH∞control problem is much simplified by the introduction of a special Youla parameterisation and auxiliary LQG problem. The approach has the advantage over previous solutions that most of the analysis concerns an auxiliary LQG problem. The influence of the weighting function which changes the controller from a usual LQG design to anH∞-norm minimisation device is transparent in this new problem formalism. The cost functions minimised in bothH2andH∞problems include cross-product terms for greater generality. The conditions under which a simplified design procedure may be used are established and related to the solution of a 1-block Nehari problem.

DOI:10.1049/ip-d.1993.0047

出版商:IEE    

年代:1993

数据来源: IET