Ram Position Control in Plastic Injection molding Machines with Higher-Order iterative Learning

In plastic injection molding, the ram position plays an important role in production quality. This paper introduces a new method, which is a combination of the current cycle feedback control (a PI controller) and a feed-forward higher-order iterative learning control (ILC), to control the ram position in injection molding. The PI controller is used to stabilize the system, and the feed-forward higher-order ILC control is used to compensate for nonlinear/unknown dynamics and disturbances, thereby gaining the precision tracking to ram position. The simulation results indicate that the new method outperforms the conventional PI controller. In addition, it outperforms the conventional ILC in the convergence performance.

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