P. Sarma et R. Rengaswamy, Multivariable gain-scheduled fuzzy logic control of a fluidized catalytic cracker unit, COMPUT CH E, 24(2-7), 2000, pp. 1083-1089
The fluidized catalytic cracker unit (FCCU) process provides an involved, c
oupled and nonlinear multivariable control problem. A systematically constr
ucted chain of gain-scheduled fuzzy logic controllers (GS-FLCs) is used wit
h some generalisable modifications. A single fixed 'full' fuzzy rule-base i
s sufficient to sustain performance for each control channel. The key FLC m
odification is the use of a sigmoidal gain-schedule (SGS) that is the signi
ficantly parameter-reduced equivalent of a flexible fuzzy input/output vari
able. The SGS simultaneously has a crisp and intuitive gain-like format, an
d together these permit relatively simple heuristic tuning for the GS-FLC.
This nonlinear GS-FLC structure permits the use of a very simple static lin
ear decoupler (SLD). The general multivariable GS-FLC/SLD construct demonst
rates very good controller performance, covering servo/regulatory and robus
tness tests. (C) 2000 Elsevier Science Ltd. All rights reserved.