Walking Beam Speed Control Based On Load Feedforward And Fuzzy Control

Walking beam furnace is the key equipment of billet rolling. Compared with pusher reheating furnace, the walking beam furnace has many advantages, so it is widely used in lots of steel rolling enterprises at home and abroad. In the billets heating process, moving beams are driven by the hydraulic control system, make the billets moving forward step by step. The hydraulic control system realizes it by adopting the strategy that asymmetric electro-hydraulic proportional valve controls asymmetrical hydraulic cylinder structure. Walking beam system is composed of fixed beams and moving beams, and it is the key equipment in walking beam furnace. Velocity of moving beams must make ensure the production cycle and the accuracy of every step, and in the same time, moving beams must hold billets up or down lightly in order to avoid billets hitting the moving beams and the fixed beams.The weight of moving beams and more than 100 billets reaches hundreds of tons. Therefore, the inertia of walking beam transport system is huge. When moving beams start or move to the height of the fixed beams, step-like load mutation causes the velocity and displacement of large amplitude drop, and accompanied by a strong shake.Currently, in the actual production process, it is difficult to accurately control the speed and displacement of the walking beams, often due to the stepping error of the moving beams, the walking beams can not sent billets to cantilever rollers and interrupt production in the final step.Based on the analysis of the working principle and the mathematical model of the walking beam transport system, A load disturbance observer is constructed to solve the problem that the load cannot be measured in engineering, and achieves feedforward control of the load disturbance. Fuzzy self-tuning PID speed control is constructed to solve the characteristics that walking beam transport system has nonlinear, large inertia, model uncertainty and so on. Simulation results show that based on the feedforward of load disturbance, the fuzzy self-tuning PID control to transport speed system is effective.