Research On Control Of Billet Stepping System In The Heating Furnace

Walking beam furnace is the most widely used and the fastest growing type of furnace in all kinds of heating furnace. Steel billets are supported by the fixed beams. The moving beams, which are installed in the bottom, lift steel billets step by step from the billet charging side to the out side by doing the rectangular movement. The moving beams is quite big and very heavy, in some large heating furnace, full load steel billets often amount to hundreds of tons. It has been a prominent engineering problem to control the walking beam in smooth and fast movement at various stages of operation cycle.In the process of steel billets production, the stop and start up of the device can cause enormous waste of resources, researchers can hardly get walking beam system to do experiments in industrial site. Thus, the advanced control strategies can not be verified timely and effectively. By analyzing the structure characteristics and the operation mechanism, the mathematical model of the walking beam system is established in the paper. Through the research and analysis on the circuit, the analog circuit model is designed. According to the experimental results, the analog circuit model can simulate the operation of walking beam system well, this lays the foundation for the realization of walking beam system in the laboratory.The velocity of the walking beam should ensure the production rhythm and guarantee the gently handle of the billet to avoid the damage of the walking beam. By analyzing the principle of the walking beam system and mathematic model, a fuzzy and feedforward control system is designed in this paper. The transfer function of feedforward channel of walking beams can not be set up accurately. However to the feedforward control, the inaccuracy of feedforward channel will make the steel billet load can not be offset, so the velocity of the walking beam can hardly been controlled well. Therefore, the fuzzy-feedforward controller is introduced, the fuzzy rule is designed according to the running condition, using the fuzzy rule, which have certain adaptive ability, to replace the feedforward channel model. Meanwhile, the system is simulated by Simulink Toolbox of Matlab, by comparing with traditional open-loop control and closed-loop control, the simulation results show that the fuzzy-feedforward PID control strategy can realize the accurate tracking of the speed and the accurate control of the displacement.