Synchro-control on steel pipe stacking electro-hydraulic servo system with four cylinders

According to synchro-motion control of four cylinders electro-hydraulic servo system in steel pipe stacking process, the nonlinear model of the system with external loop and inner loop was presented; Then, for addressing the desired load pressure for every cylinder, a nonlinear cascade controller was put forward with synchronization spatial transformation, quantitative feedback theory(QFT) and control allocation theory(CAT) to address the redundant control in external loop; Lastly, in inner loop, nonlinear disturbance observer theory(NDOB) is employed to track the desired load pressure. Simulation and practical application show that the provided controller with well synchronization performance, can effectively the four-cylinder synchronization motion control in steel pipe stacking system.