SynopsisIn the iron and steel making shops, some processes are so complex that it is difficult to formulate precise control models. In such cases, process control is made on the basis of the skilled operator's heuristic knowledge. However, utilization of skilled operator's heuristic knowledge is one of the major problems to control the process precisely. In the fuzzy set theory, skilled operator's knowledge is expressed as membership functions to control the process as well as skilled operators.The fuzzy set theory was applied to the on-line control of return fine hopper level at the sintering plant in Fukuyama Works, Nippon Kokan K.K. This was the first application of fuzzy control to the practical operation. The commercial operation has started in August 1986. As the result, the deviation of return fine hopper level decreased from 12 to 4 %/h and the amount of return fine decreased by about 2 kg/t-sinter.

No abstract

In the steel industry, up until now Factory Automation has meant the automation of a single process so as to reduce the cost of labor. However, in order t o make various products of high quality and t o raise t h e productivity and the yield of the products, FA has been developed into the CIM which means the total automation of t h e process optimum control and p r o d u c t i o n management. NKK has been pushing forward with automation based on t h e rapid progress of e l e c t r o n i c s and c o m p u t e r technology. As an example of the system, this paper presents an outline of the automation of No. 3 Cold Strip Mill constructed a t Fukuyama works in August, 1987.