The Fuzzy Adaptive Step-distance Control For The Walking Heating Furnace Based On PLC

Walking heating furnace is a kind of important heating equipment in steel industry. The operation status of this equipment will affect the production safety, the efficiency and cost of the iron and steel industry. The heating furnace is used to heat the steel bars to meet the requirement of the rolling mill, and get ready for steel bars to be rolled. Because of various reasons, the step distance would change a little, errors would be accumulated, and steel bars would sometimes fail to fall onto the output roller. This would cause an accident. The whole production line will stop due to the accident. It raised the cost of the products and reduced the productivity of the steel company. The competitiveness of the steel company was also seriously affected.Walking heating furnace is a very complex process control system with properties of nonlinear, multivariable, strong coupling and so on. Due to these properties, it is very difficult to establish a precise model for it. Therefore, the conventional control methods can not control step-distance accurately for the walking beam. So it is necessary to employ a more suitable new control strategy.This thesis was based on the research on a walking heating furnace of an iron and steel plant. The in-depth study of the production process was carried out. The reasons for the instability of step-distance were analysed. In order to increase the adaptive adjustment capacity of the system, Siemens S7-400 PLC was employed as the controller, and the fuzzy adaptive control strategy for the walking heating furnace step-distance was designed. A laser range sensor was added to the equipment. The fuzzy adaptive control for the walking heating furnace step-distance was realized. Now steel bars can always fall onto the output roller accurately. Production accidents were avoided, production cost was reduced, and the productivity and competitivity of the company were raised. Simulation was carried out with MATLAB/Simulink for this step distance adaptive fuzzy control system. Satisfying results were achieved.