摘要:

An extended method for the design of discrete-time multivariable adaptive control is presented. Unlike most adaptive control algorithms, future control inputs are, in this method, predetermined by using the long-term predictor. With this concept, applications of discrete-time multivariable adaptive controls, which have been applied to only a limited class of practical problems owing to the unboundedness of the control inputs, can be extended to some types of non-minimum phase process. In addition, it is shown that a more generalized control objective, such as minimizing a sum of quadratic errors plus a penalty on control action, can be easily adopted in the design of adaptive controllers by using the concept of a long-term predictor.

ISSN:0020-7179    

DOI:10.1080/00207178308933090

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The problem of dynamic reliability of multiplex control systems under Markovian structural perturbations is reformulated, analysed, and resolved in the context of stochastic stability and Liapunov's direct method. The failures of controllers are identified as states of a Markov process, and stability conditions are provided for a reliable performance of the multiplex control system alternating between operating (stable) and failure (unstable) structural configurations.

ISSN:0020-7179    

DOI:10.1080/00207178308933091

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

An important problem in the structure theory of linear systems is the construction of a canonical form for strongly controllable systems (i.e. surjective systems without finite zeros). The problem has been solved in principle (Morse 1973, Kronecker 1890), but without a, clear identification of the system-theoretic meaning of the construction steps. This paper proposes the concept of a ‘ train basis ’ in order to give this interpretation. The second main idea of the paper is the ‘ system associated with a sub-space ’, through which concept it is possible to translate problems concerning ‘A, B’-invariance etc. of subspaces in terms of input-output systems. In this way, we make contact with results of Willems (1980) on almost.invariance.

ISSN:0020-7179    

DOI:10.1080/00207178308933092

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The asymptotic behaviour of linear quadratic control as the control weights tend to zero may be described by means of the solution (H matrix) of a factorization equation (Harvey and Stein 1978). In this paper, a duality principle relating the above problem to the stochastic state estimation with noise-free outputs is used to provide a complete calculation of H under weak restrictions. A simple example is presented to illustrate the procedure.

ISSN:0020-7179    

DOI:10.1080/00207178308933093

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Using averaging methods of the theory of differential equations, the effects of the injection of high frequency signals, known as dithers, in non-linear systems is studied. The behaviour of the dithered system is compared with that of a smoothed one, whose non-linearity is the convolution of the dither distribution function and the original non-linearity. It is proved that if over a given time interval the smoothed system has a bounded solution, then so does the dithered system, provided that the dither frequency is high enough, and the output of the two systems can be made as close as desired. Moreover, if the trajectories of the smoothed system are asymptotically attracted to a compact set, for example a stable orbit or singular point, then the trajectories of the dithered system can be made to remain close to this set. In particular, a satisfactory explanation of quenching of limit cycldes is botained in this way. The analysis takes account of certain disturbances which might arise due to the injection of external signals. As an application of the theory, it is shown that with suitable dithers, and to within any degree of approximation, odd symmetric non. linearities which saturate can be made to behave like pure linear gains in many control systems. Finally, a comparison is made of these results with those of Zames and Schneydor (1976) in this area and the theory is illustrated by some examples.

ISSN:0020-7179    

DOI:10.1080/00207178308933094

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

This paper considers a minimal order state observer for a quadratic system. The given observer is an extension of one for a bilinear system. Sufficient conditions are given for the existence of the state observer and design procedure is presented.

ISSN:0020-7179    

DOI:10.1080/00207178308933095

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The theory of realization of linear input-output maps is applied to the study of root loci of distributed systems with bounded defining operators.

ISSN:0020-7179    

DOI:10.1080/00207178308933096

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Sufficient conditions for affine time-delay systems with state-space constraints are derived, and it is shown that the results are applicable to a control problem involving a novel type of functional constraint. The discrete-time version of sufficiency is also obtained. Numerical examples are given to compare the functional control constraints with the conventional pointwise control constraint.

ISSN:0020-7179    

DOI:10.1080/00207178308933097

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The generalized partitioning estimation method, which is well known in tho literature (for example, Lainiotis 1976), is applied to solve the bias correction filtering, predicting and amoothing problems for a linear continuous.time system with undisturbable bias subsystem. With tho aid of an initial dependent-type partitioning approach, it is shown that the Friedland (1969) elemental results con be readily extended to the more general case where the bias and the original states are mutually dependent at the initial time, and that two-stage bias correction predictors and smoothers can also be developed. Finally, the dual set of Chandrasekhar algorithms, which alleviates the computation burden for a bias correction fixed-interval smoother evolving forwards in time, is presented.

ISSN:0020-7179    

DOI:10.1080/00207178308933098

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A pH-process model for a chemical waste-water treatment plant is constructed by applying basic physico-chemical laws. The unknown composition of the wastewater is modelled by a composition of hypothetical chemical species which best describe the titration curves of real liquid samples. The dissociation parameters of the coagulant, aluminium sulphate, is also determined by using appropriate titration curves. The overall pH-model comprises a linear state model of concentrations and an implicit output model describing the physico-chemical equilibrium conditions. The estimation of the hypothetical concentrations is performed by a Kalman-type filtering algorithm obtained with the aid of a certain transformation. Using a non-linear transformation of the estimates, a deviation signal is generated and fed into the PI-controller. A feedforward control loop was connected to the algorithm and results of two simplifications of the algorithm are presented. After tuning by simulation, these algorithm variations we tested on-line in a chemical waste-water treatment plant. Comparisons of the control results are also made with the results of the permanently installed adaptive pH-controller.

ISSN:0020-7179    

DOI:10.1080/00207178308933099

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor