摘要:

A curve-fitting or prediction problem for two-dimensional or cyclic processes is defined and solved using spectral techniques. The assumed statistical model is structurally similar to the Karhunen-Loève expansion, and the technique can be implemented using the singular-value decomposition. Two examples using published data illustrate the feasibility of the method and the peculiarities associated with the problem.

DOI:10.1049/ip-d.1982.0035

出版商:IEE    

年代:1982

数据来源: IET

摘要:

The paper describes applications of control theory methods to macroeconomic policy formulation. The use of modelling concepts and techniques arising from control theory are discussed. Applications of control methods to macroeconomic models are described both for linear and for large nonlinear models. In the case of linear models, a minimal state-space representation is obtaine, a quadratic performance index adopted, and, assuming a Gaussian distribution of disturbances, the policy design problem is formulated in terms of a classical optimal control (LQG) framework. For large nonlinear models, and earlier approach involving the control of such systems using small linearised models is discussed initially. Subsequently, a direct approach, using a nonlinear optimisation algorithm, for computing optimal policies is discussd. The derivation of parametrised feedback laws and robust controls in such an optimisation setting is also described.

DOI:10.1049/ip-d.1982.0036

出版商:IEE    

年代:1982

数据来源: IET

摘要:

The paper presents a three-level hierarchical approach for solving the joint problem of system identification and optimisation. It is then applied to a batch penicillin fermentation process using a microprocessor. Detailed information about the microprocessor system utilised is given.

DOI:10.1049/ip-d.1982.0037

出版商:IEE    

年代:1982

数据来源: IET

摘要:

The optimal stochastic regulator is derived for systems which can be decomposed into subsystems with measurable state varibles and subsystems in which only noisy output measurements are available. The solution involves direct state feedback from the former subsystems and feedback via a set of Kalman filters for the latter subsystems. The total order of the Kalman filters equals that of the unmeasurable subsystems. The use of direct state feedback rather than state-estimate feedback is very desirable: the system becomes more robust, nonlinearities have less effect and, since Kalman filter are not needed for these subsystems, modelling errors are reduced. Having decomposed a large system, it is natural to ask whether subsystems can be started and controlled independently before the complete feedback control is applied. Conditions are determined where a sequential start-up procedure for the optimal system is possible. Simplifications to the structure of the controllers for servomechanisms are also considered.

DOI:10.1049/ip-d.1982.0038

出版商:IEE    

年代:1982

数据来源: IET

摘要:

The paper explores the possibility of performance improvement by the use of added delay elements. The counterintuitive phenomenon of ‘improvement by mismatch’ has been noted by several authors in the context of predictor control. This phenomenon is illustrated using a second-order example, and, in the light of this, it is demonstrated how it also may be improved by the use of delay elements. A third-order example of delay-free system improvement is described. A technique for producing good first-order estimates of design parameters is presented

DOI:10.1049/ip-d.1982.0039

出版商:IEE    

年代:1982

数据来源: IET

摘要:

A method of reducing stationary vibrations in revolving systems by using a vibration-damper system with a two-phase servomotor is proposed. The additional vibration source adopted here eliminates the vibration within one sampling period by using a sampled-data control system which makes use of the finite-settling-time method. The system is demonstrated by applying the additional vibration source to eliminate the second-harmonic vibration produced by the two-phase servomotor of a speed-control system. Tests on the system indicate that the vibration on the shaft can be reduced to zero.

DOI:10.1049/ip-d.1982.0040

出版商:IEE    

年代:1982

数据来源: IET

摘要:

An algorithm is developed to perform a relative stability test for time-invariant systems using the generalised sign matrix. The method is then extended to sampled-data control systems through bilinear transformation. The algorithm is efficient and can be easily programmed.

DOI:10.1049/ip-d.1982.0041

出版商:IEE    

年代:1982

数据来源: IET

摘要:

The problem considered in the paper refers to the general area of developing design and computational algorithms for analysing low-sensitivity time-invariant multivariable two-dimensional systems using output feedback. It is seen that the matrix-minimum principle can be used to study two-dimensional digital systems with incomplete state information for the implementation of a low-sensitivity feedback law. The results show that an observer can be used in addition to the output vector to estimate the state of the system, which in turn is used for implementing the feedback law.

DOI:10.1049/ip-d.1982.0042

出版商:IEE    

年代:1982

数据来源: IET

摘要:

A two-channel linear system ∑ is given, defined by its transfer matrixG(s), for which a (right) matrix fraction description in the formG(s)=R(s) P−1 (S)is also provided. Local output feedbacks of the formui= −Kiyiare considered, and their effect on the system ∑ is studied via the so-called D-controllability problem. This problem is solved using the above definition of ∑, and a simple criterion for its solvability is presented involving suitable submatrices ofR(S)andP(S). Finally, some results concerning the decentralised stabilisability problem, and the connection to decentralised fixed modes, are also given.

DOI:10.1049/ip-d.1982.0043

出版商:IEE    

年代:1982

数据来源: IET

摘要:

A two-channel system defined by its transfer functionG(S)is considered, and its controllability with the one of its input channels is examined after the introduction of a local output feedback with respect to the other channel (termed D-controllability). A criterion is given for D-controllability in terms of a (right) matrix fraction descriptionG(S)=R(S)P−1(S)of its transfer matrixG(S).

DOI:10.1049/ip-d.1982.0044

出版商:IEE    

年代:1982

数据来源: IET