摘要:

The authors propose a controller design method for linear multivariable systems with periodic inputs. The periodic inputs may have different periods in different input channels. The plant is assumed to be minimum phase but may be unstable. In addition to achieving closed-loop stability and input-output decoupling, the design is to satisfy prespecified bounds on relative steady-state tracking error and sensitivity function. The paper shows that, for minimum phase plants, it is possible to achieve arbitrarily small sensitivity over large bandwidth and arbitrarily small (integral square) tracking error for piecewise continuous periodic inputs in each channel. The paper proposes a design algorithm and gives an illustrative example.

DOI:10.1049/ip-d.1992.0001

出版商:IEE    

年代:1992

数据来源: IET

摘要:

A method for approximating irrational transfer functions by rational transfer functions based on the Lagrange interpolation formula is presented. The mathematical procedures required are conceptually and computationally simple. The procedure is applied to two cases, one where it is desired to approximate an irrational controller, and the other where it is desired to approximate the plant. In the latter case, it is shown that the procedure will produce a third order rational approximation with lower error than a previously reported third order approximation.

DOI:10.1049/ip-d.1992.0002

出版商:IEE    

年代:1992

数据来源: IET

摘要:

The paper introduces a new adaptive multivariable control algorithm that is able to manage processes that may present saturations on the control signals. This is the case when the calculated control signals go beyond boundaries. In many situations, the system under control may turn unstable if these limits are not considered. The first part of the paper describes the model of the process. The model consists of a variable number of inputs, because a control signal reaching saturation can no longer be considered as a free input. Next, the new control law is presented. It is based on a pole assignment strategy able to treat processes with a different number of inputs and outputs. The problem of minimising output errors when saturated inputs are present is also considered. An algorithm to recover, when possible, the control signals that are lost due to saturation is proposed. Finally, an example showing the algorithm behaviour is presented.

DOI:10.1049/ip-d.1992.0003

出版商:IEE    

年代:1992

数据来源: IET

摘要:

The modelling and control of systems with uncertain parameters which can be represented by random variables are considered. The model structure is chosen so that high-frequency lag terms may be introduced whose parameters have zero expected value. Similarly uncertain zeros may be considered. An LQG controller is obtained which stabilises the nominal plant model and also provides a degree of robustness to the uncertain poles or zeros. The LQG cost function to be minimised includes an expectation over the parameters, as well as on the stochastic signals. The design procedure introduced enables the cost function weighting terms to be parameterised in terms of the variances of the unknown parameters and a design scalar.

DOI:10.1049/ip-d.1992.0004

出版商:IEE    

年代:1992

数据来源: IET

摘要:

An approach to obtain the optimal gains for a discrete PID controller is presented. The optimal gains are obtained by minimising the variance of the output variable under feedback. The problem is formulated similarly to the Kalman filter problem and the gains are obtained from the solution of a Riccati equation. The discussion is restricted to single input single output systems.

DOI:10.1049/ip-d.1992.0005

出版商:IEE    

年代:1992

数据来源: IET

摘要:

In the paper, an intelligent advisory system for achieving diagonal dominance in the design of multivariable systems is presented. The underlying design algorithms are the Perron-Frobenius eigenstructure and pseudodiagonalisation techniques. The adviser acts as an intelligent frontend to an existing CAD suite, MVDES, which performs the actual numerical calculations and generates associated graphical plots.

DOI:10.1049/ip-d.1992.0006

出版商:IEE    

年代:1992

数据来源: IET

摘要:

Measurement error reconciliation is well known in the literature. Unfortunately, the common basic assumption of almost all the existing methods is the steady state of the process concerned. A formulation for dynamic balancing is proposed which uses the same principles as those used for static balancing. To reduce the size of the problem, a recursive algorithm is formulated.

DOI:10.1049/ip-d.1992.0007

出版商:IEE    

年代:1992

数据来源: IET

摘要:

The paper deals with the robust design of an MIMO feedback control system. It is divided into two parts. The first part presents a necessary and sufficient condition for the robustness of a unit feedback system. The uncertainty model considered in this analysis is nontrivial, and the present approach is applicable to nearly decoupled systems as well as nondecoupled systems. The second part of the paper presents an effective technique for the design of a robust, nearly decoupled MIMO system using the result of Part I. The design technique to be presented in Part II can be applied to a nonminimum phase plant.

DOI:10.1049/ip-d.1992.0008

出版商:IEE    

年代:1992

数据来源: IET

摘要:

The high costs associated with many fermentation processes in an increasingly competitive industry make the optimisation of bioreactor performance very desirable. Attempts to improve performance have primarily been focused on the development of online adaptive methods. Although these techniques can provide the optimum solution, each had limitations in practical implementation. The paper addresses these problems and considers their effects on the optimisation of bioreactor performance. An online time series model is sought in order to evaluate the steady-state performance of the bioreactor. A simple algorithm is developed around this theme and is analysed to show convergence to the optimum solution. Nonlinear simulation results, using the Monod equations for yeast fermentations, are presented. For this processes, two approaches using an online identified linear model or nonlinear model, are shown to give optimum results.

DOI:10.1049/ip-d.1992.0009

出版商:IEE    

年代:1992

数据来源: IET

摘要:

In the paper a regulator, called the mean regulator, is presented for stochastic discrete systems. The mean regulator minimises the supremum of the mean of the absolute value of the system outputs for all disturbances in a space RD and all time. A performance index and a random disturbance space are proposed. The analysis, which is restricted to discrete-time single-input single-output stochastic systems, yields the mean regulator and considers its stability. The simulations illustrate the operation of the mean regulator.

DOI:10.1049/ip-d.1992.0010

出版商:IEE    

年代:1992

数据来源: IET