Nonlinear control on steel pipes stacking electro-hydraulic servo system with four cylinders

According to synchronization motion control with four cylinders in steel pipe packing process, nonlinear model of the system was presented. Then a nonlinear cascade controller was put forward. The provided approach integrated synchronization spatial alternation, quantitative feedback theory(QFT) and control allocation theory(CAT) to coordinate the redundant actuator control in external loop; moreover, the desired load pressure for every cylinder was confirmed. In inner loop, nonlinear disturbance observer theory(NDOB) was employed to track the desired load pressure. Simulation and application shows that the provided approach with high speed response, can implement the four-cylinder synchronization motion control in steel pipe packing system.