Nikolai Vatanski

Control Reconfiguration in Networked Control System

Abstract In the research on the networked control systems (NCS) the performance of the control system is assumed to be affected by network induced parameters such as delays, jitters, packet losses, link failures. In this paper a reconfiguration of the network control is presented. The upper bound delay of the transmission time of a packet is monitored with the network calculus based algorithm. A modification of the network parameters due to a failure is reflected by an increase of the upper bound value. Two reconfiguration procedures are proposed which aim at compensating the effect of the failure on the QoS.

CONTROL LOOP PERFORMANCE MEASURES IN THE EVALUATION OF PROCESS ECONOMICS

Abstract The number of control loops used in industry is growing continuously and there are problems in keeping them working at a satisfactory level. One reason for the poor performance is the lack of maintenance of control loops. Economical benefits can result from the better maintenance of control loops. In this paper the economic aspects of control loop performance measures are discussed. A strategy is proposed to evaluate the economics of control performance using control loop performance measures. In addition, a case study on an industrial process is also described. It is anticipated that the framework introduced in this paper may prove useful in presenting control quality in a common language understood by operators, engineers and management.

USE OF UPPER BOUND DELAY ESTIMATE IN STABILITY ANALYSIS AND ROBUST CONTROL COMPENSATION IN NETWORKED CONTROL SYSTEMS

Abstract Recent interest in networked control systems (NCS) has instigated research in various areas of both communication networks and control. The analysis of NCS has often been performed either from the network, or the control point of view and not many papers exist were the analysis of both is done in the same context. Here an overall analysis is presented. In the paper the procedure of obtaining the upper bound delay value in the switched Ethernet network is proposed and the obtained delay estimate is used in stability analysis of the feedback loop and in the control compensation. The upper bound delay algorithm is based on the network calculus theory, the stability analysis uses the small gain theorem, and control compensating strategy is based on Smith predictor, where however the upper bound delay is utilised in obtaining the delay estimate.

Support vector machines for detection of analyzer faults- a case study

Abstract The aim of the work presented in this paper is to assess the ability of support vector machines (SVM) for detecting measurement faults. Two different support vector machine approaches for detecting faults are tested and compared to neural networks. The first method is based on a SVM regression model together with an analysis of the residuals whereas the second method is based on a SVM classifier. The methods were applied to a rigorous first principles based dynamic simulator of a dearomatization process.

The Economical Aspects of Control Loop Performance Measures in the Remote Maintenance Center Concept

Abstract The number of control loops used in industry is growing continuously and there are problems in keeping them well tuned. In addition to maintenance, there is also always a need to improve the performance. Since the number of personnel is being reduced, companies are using, to an ever-increasing extent, a range of remote expert services for control loop performance evaluation. In this paper a set of performance indices appropriate to process monitoring and assessment is presented, and the economical aspects of these indices are evaluated. The economical evaluation has been mainly carried out from the remote center point of view. Finally, two case studies from industry are described.