Modeling and control simulation for force couple leveling system of hydraulic press

This paper studies force couple leveling system of heavy hydraulic press. A multi-input and multi-output nonlinear model is established on the basis of analyzing hydraulic structure and block kinematics. A cascade control structure is designed for the leveling system. In the outer loop, each corner follows the average displacement other two corners adjacent to it using PI method, and the desired pressure of inner loop is given. In the inner loop the cylinder pressure is controlled using parameter variable PD method. Modeling and control simulation in Matlab show that the designed control method has a good synchronization effect.