摘要:

Based on a centralized formulation for stochastic steady-state optimizing control problems, a hierarchical formulation for such problems is proposed and analysed. A hierarchical joint system identification and set-point optimization approach is devised and implemented, with two different iterative strategies for on-line stochastic optimizing control of large-scale steady-state industrial processes. The optimality and convergence of the approach are examined. Joint dynamic and steady-state simulation studies are provided, showing that the approach is very efficient and reliable

ISSN:0020-7179    

DOI:10.1080/00207179108953608

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

In this paper we examine the ability of H∞-control theory to perform actually linear control of distributed parameter systems in non-trivial cases. The process to be controlled is originally an alumina furnace, which is modelled by trivializing combustion phenomena as a rather special heat exchanger. This process has an intrinsic non-minimum phase, due to its particular geometry. It is modelled as a non-linear partial differential system, which is linearized and controlled using H∞-techniques. Algorithms are developed to accomplish this task, in particular to factorize the (transcendental) transfer function into its inner and outer parts. Simulation and comparisons with classical controllers are performed

ISSN:0020-7179    

DOI:10.1080/00207179108953609

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

This paper presents two simple but effective algorithms for selecting the weighting matrices needed in designing linear quadratic optimal control for systems with linear uncertainties. By utilizing the Lyapunov stability criterion, it is shown that the optimal state feedback control law designed for the nominal system can stabilize the uncertain system, provided the uncertainties satisfy the so-called matching conditions and are within a given bounding set. The methods are tested for three examples, and the results show that the current methods have wider application ranges than some approaches treating similar problems in the literature. Furthermore, this paper considers the case in which matching conditions are not exactly satisfied. A measure of mismatch is adopted from the literature, and a threshold on the mismatch is found to guarantee that the optimal controller designed for the system without the mismatching uncertainties is effective when the mismatching part is added. Finally, a method for adjusting the weighting matrix of the state variables in the cost function is suggested to facilitate the computation of the threshold value

ISSN:0020-7179    

DOI:10.1080/00207179108953610

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A new approach to predictive controller design for bilinear systems has been developed based upon discrete pulse orthogonal functions, and some important analytical properties of the general predictive control system have been obtained. The authors prove that any control system based internal model, linear or non-linear, exhibits an interesting ‘dual relationship’ between the regulatory behaviour and the servo behaviour. It is this dual relationship that brings the excellent robustness and high ability to correct unmeasured disturbances and model mismatch. In the new design procedure, it is not necessary to calculate the non-linear optimization problem because all calculation is between the algebraic equations. The final control action becomes the solution of a least-squares problem which contains the adjustable parameters; therefore the tuning is also much simpler. Two examples illustrate that the method is effective

ISSN:0020-7179    

DOI:10.1080/00207179108953611

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A rigorous gain scheduling approach is developed to design non-linear state-feedback controllers for sampled continuous-time non-linear systems. All the information needed in the design can be obtained from measurements of the continuous-time plant about selected equilibrium points. The performance of the resulting controllers is explored using two examples

ISSN:0020-7179    

DOI:10.1080/00207179108953612

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A new method for model reduction of linear discrete systems is proposed. It is based on the weighted impulse response gramians proposed here for discrete systems. These gramians are extensions of the ones proposed for linear continuous systems (Agathoklis and Sreeram 1988 a, 1990) and contain information on the input-output behaviour of the system. The reduced-order models are obtained by retaining the states corresponding to the dominant eigenvalues of these gramians and are stable if the original system is stable. The method is illustrated by a numerical example and is compared with well-known model reduction techniques

ISSN:0020-7179    

DOI:10.1080/00207179108953613

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Plant bypass has been suggested as a solution to the problems that arise when adaptive systems are used to control non-minimum phase plants, or plants with unmodelled dynamics. It is shown that plant bypass is normally not feasible. It is demonstrated that realizable adaptive systems using plant bypass are combined fixed parameter and adaptive feedback systems. The fixed parameter feedback provides adaptive gain feedback (AGF). An adaptive control law is modified using AGF, and the characteristics of this modified adaptive scheme are investigated

ISSN:0020-7179    

DOI:10.1080/00207179108953614

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The robustness properties of sliding mode behaviour are considered in terms of the choice of non-linear control structure. The performance of two classes of variable structure controllers in the presence of unmatched uncertainty is discussed. Criteria for suitable choice of a non-linear control structure are presented, and the concept of a performance sliding mode is introduced. A numerical example is given to illustrate the phenomenon described

ISSN:0020-7179    

DOI:10.1080/00207179108953615

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

It is proved that a certain sample auto- and cross-correlation Hankel matrix can be used to develop an effective state-space model identification procedure. By incorporating data correlation with a state-space model identification method, identification bias, which is inherent in using the singular value decomposition of a noise-corrupted Hankel data matrix, can be significantly reduced. The proposed new identification procedure is different from other state-space identification methods which use correlation or covariance matrices, since the input excitation signals are not limited to a white gaussian noise or to an impulse. These inputs can be any time functions provided the persistent excitation condition is satisfied

ISSN:0020-7179    

DOI:10.1080/00207179108953616

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A technique of indirect adaptive control based on certainty equivalence for input output linearization of non-linear systems is proven convergent. It does not surfer from the overparameterization drawbacks of the direct adaptive control techniques on the same plant. This paper also contains a semi-indirect adaptive controller which has several attractive features of both the direct and indirect schemes

ISSN:0020-7179    

DOI:10.1080/00207179108953617

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor