摘要:

The problem considered in this paper is the design of a feedback control law such that the closed loop system meets desired performance specifications. Particularly, we are dealing with the exact model matching problem for systems with two dimensions, using periodic state and output feedback, assuming that the states and the output are accessible to measurements, and that noise is not present. The method leads to necessary conditions for the solution of the problem. To illustrate the procedure, two step-by-step examples are presented.

DOI:10.1049/ip-d.1993.0031

出版商:IEE    

年代:1993

数据来源: IET

摘要:

The problems of controller windup and directional change in controls, in controllers for multiinput multioutput processes with input saturation, is considered. To avoid the windup problem, a generalisation is proposed for the conditioning technique based antiwindup compensator, by introducing a filtered setpoint. This provides a parameterisation to deal with situations where the original conditioning technique was not suitable. To reduce the effect of directional change in controls due to the multiple saturation, further modifications to the conditioning technique are proposed. An interesting outcome is that the generalised antiwindup compensator due to Åström and Wittenmark is interpreted in terms of the conditioning technique; moreover, these interpretations are used to introduce modifications to their scheme in order to deal with the problem of directional change in controls.

DOI:10.1049/ip-d.1993.0032

出版商:IEE    

年代:1993

数据来源: IET

摘要:

Quadratic programming provides an obvious means of handling constraints within the context of generalised predictive control (GPC). However, the resulting algorithm may be computationally demanding, is not robust with respect to infeasibility, constraint redundancy and degeneracy, and has no attendant general stability properties. An alternative optimisation procedure is proposed and used in conjunction with stable GPC to overcome all these difficulties.

DOI:10.1049/ip-d.1993.0033

出版商:IEE    

年代:1993

数据来源: IET

摘要:

Decentralised control of an interconnected power system is attempted using high gain feedback methodology. Two cases are presented treating the interactions as unknown in the first case and as known in the second case. The effect of interactions is nullified by using a high gain factor in the first case whereas a bound on the high gain factor is computed to nullify the effect of known interactions in the second case. The results are illustrated on a two area power system [1].

DOI:10.1049/ip-d.1993.0034

出版商:IEE    

年代:1993

数据来源: IET

摘要:

The robust stability of a class of uncertain systems involving internal delays while being regulated by a sliding mode controller (SMC) is studied. The method for designing a SMC is proposed for the generation of a sliding motion in the system. The robustness property and asymptotic stability of the system are discussed and conditions for the design of the switching hyperplane are given. Further generalisation results, which lead to a simple design and implementation, are made for the case when the system is in companion form. A method is proposed for the elimination of limit cycles in systems being regulated by a relay SMC while allowing the generation of sliding motion and thus ensuring the closed-loop asymptotic stability.

DOI:10.1049/ip-d.1993.0035

出版商:IEE    

年代:1993

数据来源: IET

摘要:

Generalised predictive control with end-point state weighting is an extension of generalised predictive control (GPC) by including a weighting of the state vector at the end-point of the receding time frame. A zero weight reduces the algorithm to GPC, whereas an infinite weight gives constrained receding horizon predictive control. Guaranteed stability properties are derived based on the use of nonzero weighting. These stability results hold for any horizon greater than or equal to one. Some illustrative simulations are given.

DOI:10.1049/ip-d.1993.0036

出版商:IEE    

年代:1993

数据来源: IET

摘要:

It is shown that the characteristic equation (CE) of annth-order, ‘single-pumping’, continuous-time periodic system is annth-order polynomial equation in thez-plane, whose coefficients (for zero-mean, symmetric pumping of magnitudeK) are power series inK2. For cisoidal cases, the expressions for theK2,K4andK6terms have been obtained. Further, for non-cisoidal systems, theK2term has also been obtained. Such CEs allow one, for the first time in literature, to study analytically the behaviour of periodic systems for any pumping frequency and even for large values ofK. TheKbehaviour of several frequency-normalised, cisoidal systems has been studied to illustrate this point. This study further reveals that, (i) particularly for high-frequency systems, theK2terms of the power series are alone capable of describing the system behaviour over a wide domain, and (ii) as the value ofKis increased, the roots, in general, move in an oscillatory fashion.

DOI:10.1049/ip-d.1993.0037

出版商:IEE    

年代:1993

数据来源: IET