Flash butt welding of large workpieces based on model-free adaptive control

The hydraulic system of flash welding machine and loading system has nonlinearity, force coupling arising from mechanical structure and time-varying parameters and demands huge upset force, respond with high-speed and two loading hydraulic cylinder move and load synchronously while the cylinders sharing the even load. It´s difficult to model mathematics accurately. So we designed the control scheme of model-free adaptive and the controller of model-free adaptive. By simulation, we succeeded in solving the problem that it is difficult to model mathematics accurately. Simulation result show that the error of dynamic pressure synchronization is little and that the error is stable. The control effect of upset force servo is good and the output of upset force servo is stable. The control scheme is feasible.