The automation of complex industrial batch processes is a difficult problem
due to the extremely nonlinear and variable system behavior or the conflic
ting goals within the different process phases. The introduction of a singl
e multiple-input multiple-output controller is not useful because of the ra
ther high design effort and the low transparency of its complex structure.
A more suitable hierarchical fuzzy-logic (FL) based supervisory control con
cept is proposed in this paper. It permits the decomposition of the complex
control problem into a series of smaller and simpler ones. In the upper le
vel of the hierarchy the FL-based supervisory controller classifies the act
ual process phase in terms of the available process sensor signals and acti
vates dynamically the appropriate situation specific low-level controllers.
This paper presents the generic concept of the FL supervisory controller t
hat comprises both a FL process diagnosis and a control mode selection as w
ell as experiences with the industrial application.