The FLS application of fuzzy logic

This paper will survey the application of fuzzy logic by F.L. Smidth & Co. A/S (FLS) for control of rotary cement kilns. The presentation is given in retrospect, starting in 1974 when FLS heard about fuzzy logic for the first time. The most important milestones in our work with high-level process control are presented, with special emphasis on the role of fuzzy logic. The present status of the FLS Fuzzy II system is outlined and the development trend for high-level process control systems as expected by FLS Automation is discussed.