System-Decomposition-Based Multilevel Control for Hydraulic Press Machine

In this paper, a novel system-decomposition-based multilevel control method is proposed to control the complex hydraulic press machine system. The key idea in this proposed method is to decompose the system complexity into a group of simple subsystems, and the control task is shared by a group of simple subcontrollers. First, the complex nonlinear system is decomposed into a group of simple subsystems according to the process knowledge, upon which every subsystem is easily controlled by a simple subcontroller. Then, a sequence control strategy is developed to help these subcontrollers to handle the coupling between subsystems. Finally, the proposed method is applied to control a practical hydraulic press machine and compared with the traditional proportional-integral-derivative control.