Title: Influence of cross-point level of membership functions in fuzzy two-term control

Authors: B.M. Mohan, Arpita Sinha

Addresses: Department of Electrical Engineering, Indian Institute of Technology, Kharagpur 721302, India. ' Department of Electrical Engineering, Indian Institute of Technology, Kharagpur 721302, India

Abstract: In this paper, influence of cross-point level of membership functions in fuzzy two-term (PI or PD) control is studied. Important outcomes of this study are: (i) whenever membership functions are considered with cross-point level less than 0.5, control output generated by two-term controller is piecewise continuous and (ii) controller performance is inferior as long as cross-point level is less than 0.5. The first outcome of the study is proved analytically and the second outcome is discussed with intuitive reasoning and demonstrated numerically with examples as it is difficult to prove analytically.

Keywords: fuzzy numbers; fuzzy control; controller modelling; cross-point level; membership functions; fuzzy logic; controller performance.

DOI: 10.1504/IJAAC.2007.014015

International Journal of Automation and Control, 2007 Vol.1 No.2/3, pp.133 - 144

Published online: 11 Jun 2007 *

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