摘要:

Davison's robust, multivariable, feedback-feedforward controller (DAVISON, E.J.:IEEE Trans., 1976, AC-21, pp. 35–47) is applied to the control of a pilot-scale binary distillation column, as a master loop in a cascaded configuration. The inner or slave loop consists of the original plant with multiloop proportional control. This cascaded configuration is shown to have a number of advantages for practical implementation. The performance of the controller is evaluated by experimental application to a computer-controlled distillation column. The robust controller gives improved control performance compared to that achieved using conventional multiloop proportional plus integral plus derivative (PID) control.

DOI:10.1049/ip-d.1983.0037

出版商:IEE    

年代:1983

数据来源: IET

摘要:

The paper presents a new servo-system design technique called the model-following method. The most remarkable feature of this technique is that the transmission property and the sensitivity can be specified separately from each other and arbitrarily.

DOI:10.1049/ip-d.1983.0038

出版商:IEE    

年代:1983

数据来源: IET

摘要:

Regulation against offsets such as those induced by load disturbances is a principal requirement in process control, and is commonly achieved by the integral term in the classical PID algorithm. It is important, therefore, that self-tuning controllers attain the same objective along with their useful adaptive property. In an important class of self-tuners based on predictive control theory two problems arise: the well known ‘λ offset’ originating from the weighting placed on control activity and the hitherto little recognised ‘prediction offset’ which stems from possible bias in the prediction of the auxiliary output variable. This bias stems from the estimation of the predictor model in positional form. Variousad hocsolutions have been proposed in the literature, such as inserting a forward-path integrator; the weaknesses in these ideas are explored in the paper. A novelk-incremental predictor is derived which solves the offset problem whilst retaining the other attributes of the self-tuning controller such as its model following performance. A by-product of the predictor is that the estimation becomes better conditioned numerically as it works on zero mean data. Moreover, the design is robust in the sense that the freezing of estimation does not detract from its offset elimination property.

DOI:10.1049/ip-d.1983.0039

出版商:IEE    

年代:1983

数据来源: IET

摘要:

An important class of dual-delay feedback systems of open-loop transfer functionG(s)=kexp (–Xs)/{1 –exp ( –Ws)} is shown to be unstable if ratioX/Win noninteger. By means ofz-transform techniques, it is shown that, by using a feedback transducer that senses over a substantial distance either side of its central axis, closed-loop stability may be restored. Such transducers, here termed ‘wide-beam sensors’, include transmission, backscatter and natural radiation types, as well as electromechanical conveyor-belt weighers etc. The paper demonstrates that designing transducers for very narrow beams may not be desirable from the overall system viewpoint.

DOI:10.1049/ip-d.1983.0040

出版商:IEE    

年代:1983

数据来源: IET

摘要:

The paper considers a general state-space model of three-dimensional (3-D) systems, i.e. dynamic systems varying with respect to three independent variables. Two problems are studied and solved. The first problem is that of determining and computing the system transfer function matrix by using directly the state transition matrix of the given state-space model along with the system characteristic polynomial. This problem is solved through an extension of the well-known Fadeeva-Leverier algorithm to the 3-D case, and a transfer function computation formula is derived which can be implemented in an iterative way. The second problem is that of factorising the transfer function of single-input single-output systems via state-variable feedback. This problem is solvable under certain conditions only if the numerator of the open-loop transfer function is by itself factorisable in three 1-D polynomials. Otherwise the factorisation is restricted to the denominator of the closed-loop transfer function. The factorisation algorithm derived provides the state-feedback gain vector through the solution of a set of algebraic equations. Two nontrivial examples are worked out, and an interpretation of the 3-D model of the paper for the case of an elliptic distributed-parameter system in 3-dimensional spatial domain is given.

DOI:10.1049/ip-d.1983.0041

出版商:IEE    

年代:1983

数据来源: IET

摘要:

In this paper, a new approach is developed for the detection of malfunctioning sensors for large-scale linear interconnected dynamical systems. The main idea used is to do an overlapping decomposition in order to design multiple decentralised observers. Differences between the same state as estimated by the different observers can be used to isolate the malfunctioning sensors. A sixth-order ladder network example is used to illustrate the approach.

DOI:10.1049/ip-d.1983.0042

出版商:IEE    

年代:1983

数据来源: IET

摘要:

The operational matrix for performing integration of block-pulse functions is extended to inverse multidimensional Laplace transforms. The inversion algorithm only consists of two simple algebraic operations: multidimensional bilinear transformation and long division of multivariable polynomials. The method is very suitable for computer programming.

DOI:10.1049/ip-d.1983.0043

出版商:IEE    

年代:1983

数据来源: IET

摘要:

The paper describes the development of an adaptive regulator which is suitable for low-cost consumer control applications where single-chip microcomputer implementation is necessary. The regulator, which is derived by simplification of the well known generalised minimum-variance self-tuning controller, uses a variable forgetting-factor stochastic approximation variant of the recursive least-squares parameter estimator. Results obtained by digital simulation are used to compare the performance of the adaptive regulator to that of the full UD-filter implementation of the self-tuning controller and to that of a limited precision integer arithmetic version of the simplified self tuner. Practical results are also presented to illustrate the behaviour of the regulator when implemented on a commercially available single-chip microcomputer and controlling a real system.

DOI:10.1049/ip-d.1983.0044

出版商:IEE    

年代:1983

数据来源: IET

摘要:

A method is proposed for the design of constant-gain feedback control laws which reduce trajectory sensitivity to small system parameter variations and ensure the prescribed degree of stability for discrete-time systems. The selected performance index is of standard linear regulator type; modified to include a quadratic sensitivity term and weighting function (α)2kwith α > 1, which ensures that the closed-loop poles will lie inside the circle of radius 1/α in the complex plane. An example of a two-area load frequency control system is presented to illustrate the application of the design procedure.

DOI:10.1049/ip-d.1983.0045

出版商:IEE    

年代:1983

数据来源: IET

摘要:

The paper shows how a certain self-tuning algorithm can be interpreted as a self-tuning PI controller, and this algorithm has been successfully tested on a full-scale pH neutralisation process. Extended trials showed that although this process could be well controlled by a fixed parameter PI controller, the self-tuning algorithm could easily find suitable fixed parameter values for the controller, whereas human operators found the tuning difficult, if not impossible.

DOI:10.1049/ip-d.1983.0046

出版商:IEE    

年代:1983

数据来源: IET