A Critique of Fuzzy Logic in Control

The idea to incorporate the ‘experience’ of a human process operator in the design of a controller using fuzzy logic is discussed. Fuzzy control is typically introduced by pointing out that humans are able to control highly complex and non-linear problems. We argue heuristically, that this is not generally true, and furthermore limited only to special circumstances. The paper also briefly surveys concepts of fuzzy-set-theory.

‘The basic idea behind this approach was to incorporate the ‘experience’ of a human process operator in the design of the controller. From a set of linguistic rules which describe the operator's control strategy a control algorithm is constructed where the words are defined as fuzzy sets. The main advantages of this approach seem to be the possibility of implementing “rule of thumb” experience, intuition, heuristics, and the fact that it does not need a model of the process.’ Kickert and Mamdani, 1978¹