Based on the similarity between prevalent fuzzy logic controllers (FLC
) and the conventional robust controller, i.e., the variable structure
controller, control theoretic analysis of a fuzzy control system is p
resented in the sense of Lyapunov, As well as the robustness of the fu
zzy control system against uncertainties of a controlled process, this
analysis gives an account of the relationship between control perform
ance and the design parameters of the FLC, which has been obscure in t
he theory of fuzzy control.