Robust stability of single input fuzzy system for control of industrial plants with time delay

Issue title: Theoretical advances of intelligent paradigms

Article type: Research Article

Authors: Yordanova, Snejana

Affiliations: Faculty of Automation, Technical University of Sofia, 1000 Sofia, 8 Kliment Ohridski blvd., Bulgaria. Tel.: +359 2 965 3313; Fax: +359 2 965 2447; E-mail: sty@tu-sofia.bg

Abstract: Most industrial plants are complex, nonlinear, time-varying with time delay, difficult to control. The single input fuzzy controllers (SI FCs) are promising in satisfying the high performance demands to the control systems of such plants and ensuring the fuzzy system stability, coping with system nonlinearity, plant model uncertainty and SI FC design. The aim of the present investigation is to derive robust stability requirements for an incremental PI-like SI FC closed loop system that serve the development of a SI FC design method for the control of industrial plants with time delay and model uncertainty. The main contributions are: 1) modification of the Popov stability approach to study the SI FC system stability and to derive design rules; 2) derivation of robust stability criterion for a SI FC system and on its basis development of a SI FC tuning algorithm. The results are applied for the stabilisation of the air temperature in a furnace using MATLAB™. The advantages of the designed SI FC system are assessed in comparison with ordinary PI control system via simulations. The SI FC system preserves stability for a great range of plant uncertainties. The tradeoff is longer settling time of the nominal system transient responses.

Keywords: Frequency domain, MATLAB, single input fuzzy controller design, system robust stability, temperature control, time delay

DOI: 10.3233/IFS-2009-0413

Journal: Journal of Intelligent & Fuzzy Systems, vol. 20, no. 1-2, pp. 29-43, 2009