DSP‐Based adaptive fuzzy velocity/pressure control of injection molding machines

The design and implementation of a low‐cost DSP‐based fully digital velocity/pressure (V/P) controller for hydraulic injection molding machines is proposed. This system includes an analog potentiometer to sense position signal and a fixed‐point 16‐bit DSP with built‐in 10‐bit ADCs. An in‐parallel interlaced sample‐and‐hold structure is proposed to improve the accuracy of computing low velocities due to noise contamination and using low‐resolution ADCs. PI control is employed in V/P control loops to provide compatibility with commercial cards. An adaptive fuzzy control is adopted to overcome the pressure drop at the V/P transfer point. Finally, simulated and experimental results validate the proposed algorithms.