Abstract: The free forging hydraulic press has the characteristics of high working pressure and frequent direction change, therefore the smooth and accuracy control of the part with large movement inertia is required and this kind of control is very difficult to carry out. By studying on the characteristics of the free forging hydraulic press, a predicted multi-mode fuzzy control technology is developed. Corresponding to the different moving area of the slide block, fuzzy velocity, fuzzy position and Bang-Bang control are utilized, resulting in high speed, smoothness and positioning accuracy. The influence of movement delay and inertia on the control performance and accuracy is reduced by using the prediction algorithm. By using this control system, the accuracy of ±1 mm for the moving slide block and forging speed of 120 times per minute are achieved. Furthermore, the influence of the movement delay of the press is reduced, the hydraulic impact and machine vibration are also controlled effectively.

Key words: Forging, Fuzzy control, Hydraulic press, Prediction algorithm