A fuzzy logic controller for the molten steel level control of strip casting processes

The strip casting process characterized to produce steel strips of thickness ranging 1-5 mm directly from molten metal has been drawing increasing interest because it skips over some of the conventional hot rolling processes. However, since there are a number of process parameters and their relationships are somewhat complex, realization of the process design and quality control is accordingly considered to be difficult. In this case, construction of a multi-dimensional fuzzy logic controller by conventional methods is extremely difficult and therefore needs much time and effort. To overcome this difficulty, a new design technique of a fuzzy logic controller is proposed, that greatly simplifies the design procedure by defining simplified design parameters associated with the controller. In the design procedure, the major design parameters of the controller are simplified by observing several aspects that appear in design procedures of the fuzzy membership function and the rule base. This design technique is applied to a strip casting process and a series of simulations is carried out for various design parameters. Based on these results it is found that the proposed design technique can drastically simplify the design procedure and that the designed fuzzy logic controller results in satisfactory process response.