Title: Analytical tuning method for cascade control system via multi-scale control scheme

Authors: Jobrun Nandong

Addresses: Department of Chemical Engineering/CSRI, Curtin University Sarawak, 98009 Miri, Malaysia

Abstract: Cascade control strategy has been widely used in process industry owing to its superior disturbance rejection performance over that of the standard single-loop control. Designing the cascade control system is a challenging task, especially for an unstable time-delay process. In this paper, based on the multi-scale control scheme, a new analytical tuning method is presented. The method is applicable to stable and unstable processes where it can be implemented through a fixed or variable tuning approach. In the variable tuning approach, one adjustable tuning parameter is sufficient to obtain desired cascade control performance with the aid of a set of analytical tuning formulae providing direct relationship between the controller parameters and model parameters. Meanwhile, the fixed tuning approach uses a set of empirically developed rules to determine the controller parameters. Numerical studies demonstrate the effectiveness of the proposed method compared with several established cascade control designs reported in the literature.

Keywords: cascade control; robust tuning; PID control; time-delay; unstable processes; multi-scale control; process industry; analytical tuning; controller design.

DOI: 10.1504/IJAAC.2016.076460

International Journal of Automation and Control, 2016 Vol.10 No.2, pp.167 - 192

Received: 11 Jun 2015
Accepted: 29 Jan 2016
Published online: 09 May 2016 *

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