László Keviczky

Paper: Self-tuning adaptive control of cement raw material blending

A new, modified self-tuning (ST) minimum variance (MV) regulator algorithm developed for multiple input multiple output (MIMO) systems is presented with required average for finite time (RAFT). This control strategy has been developed for the self-tuning optimal control of cement raw material blending. After a brief survey of the technological background the algorithm of MIMO-ST-MV-RAFT control strategy is derived. A self-tuning blending control system is described with real-time experimental results illustrating the efficiency of the new multivariable regulator.

Robust detection filter design in the presence of time-varying system perturbations

This paper discusses the problem of designing detection filters for a class of linear time-varying systems. The basic contribution of the paper is that by, applying a time-invariant equivalent representation of the original time-varying system, it is possible to construct a detection filter such that the solution of the design problem can be solved using algebraic methods and geometric concepts similar to the case of time invariant situations.

An H/sub /spl infin// filtering approach to robust detection of failures in dynamical systems

Using results on H/sub /spl infin// output estimation theory this paper deals with the problem of designing robust detection filters in a continuous time setting for detecting failures in uncertain dynamical systems where methods for decoupling of the fault effects from system perturbations are not available. Through the appropriate choice of the filter gain a tradeoff is made between the effect of worst-case disturbance and L/sub 2/ norm of the filter error.<<ETX>>

Paper: Adaptive load-frequency control of the hungarian power system

The paper deals with the modelling of the power stations and the interconnected power systems for the design of the load-frequency controller of the Hungarian power system. It presents an adaptive regulator which uses the a priori known information and satisfies the multi-objective character of the control. The elaborated control strategy performs the following objectives: •-It eliminates the effect of the area load fluctuations to the tie-line power. •-It guarantees the scheduled value of the exported/imported energy. •-It reduces the commands sent to power stations. •-It satisfies the requirement with minimum cost. The paper shows the real-time experiments with the implemented adaptive regulator which is presently applied for the load-frequency control of the Hungarian power system.

Combined Identification and Control: Another Way

Abstract A new generic optimal controller structure and regulator design method are introduced, avoiding the solution of polynomial equations. The model sensitivity properties of some combined identification and control schemes are investigated. It is shown that the new structure is superior to the others. An applicable strategy for iterative control refinement based on the generic scheme is presented and illustrated by simulation examples. The adaptive version of the control refinement strategy is also demonstrated.

H∞ Detection Filter Design for Linear Systems: Comparison of Two Approaches

Abstract This paper discusses the robust detection filter design problem when geometric methods for decoupling the failure modes from modelling uncertainties and exogeneous deterministic disturbances are not available. Fundamental solutions of the H∞ detection filter problem are reviewed. Two basic design methods related to two basic worst-case modelling approaches which require the solution of one or two Riccati equations, respectively, are compared to each other. Despite different posing of the problems both alternatives may guarantee robustness against modelling uncertainties and external disturbances with respect to a particular failure mode thus improving filter sensitivity to faults.

Direct Methods for Self-Tuning PID Regulators

Abstract Two algorithms are presented for self-tuning PID regulators. The first method is based on the explicit identification of a second order process model with time delay and an explicit formula ensuring prescribed overshoot of the process output. The second method applies an implicit identification technique which directly estimates the PID regulator parameters using a special form of stochastic approximation algorithms. Simulation results and comparison are also given.

Optimality of two-degree of freedom controllers in H 2 - and H ∞ -norm space, their robustness and minimal sensitivity

Abstract A special generic structure of two-degree of freedom controllers and a connected closed-loop system parametrization with optimal regulator design methods are discussed. The optimality is expressed by two simple serial compensators based on the concept of the nearest inverse and can be performed in H 2 - and H ∞ -norm space. It is shown how these optimal filters are computed. The optimal sensitivity properties of this scheme are also analysed.

A New Structure to Design Optimal Control Systems

Abstract A new structure is introduced to design optimal pole placement controllers avoiding the explicit solution of polynomial equations.

Identification and adaptive control of a glass furnace

The paper presents the modelling and control of a glass furnace. A portable process computer laboratory was applied. The computer was provided by a process control program and control tasks. Based on normal operating records experiments were designed and a model with three inputs and outputs of the furnace was elaborated. By means of identified models the glass level was successfully controlled by a self-tuning regulator.