Research And Development Of The Control System In The New Servo Hydraulic Press

Hydraulic press is one of the most widely used equipments in forming process, it canbe used in metal forming, bending, stretching, cutting, powder molding, extrusion etc. Anew servo hydraulic press studied in this paper, which an ac servo motor is used, changesthe output flow of the quantitative pump by adjusting the revolving speed of the motor, andthen the precise control of the moving beam is realized. The new servo hydraulic press canovercome the shortage of common hydraulic press, such as high energy consumption, highnoise, complex hydraulic system, and high cost, it has many advantages, such as energyconservation, low noise, wide range of speed regulation, high processing accuracy, highflexible control, simple hydraulic system, convenience in maintenance, high degree ofautomation, and lower cost. This paper’s main research works are as follows:(1) Through consulting a large number of domestic and foreign relevant literature andinformation, try to completely know about the present research situation and developmenttrend of hydraulic press, direct driving pump control servo system, intelligent controlmethod. A study on overall control scheme, hydraulic control system and electrical controlsystem of the new servo hydraulic press is done, some important components of the systemare selected and presented, the working process of the new servo hydraulic press isanalyzed, and the relative control procedures are written.(2) The mathematical model of the electro-hydraulic position control system in thenew servo hydraulic press is established, in which the link of hydraulic cylinder controlledby pump is derived in detail, and then analyze the important characteristics of the controlsystem.(3) Through PID control and MATLAB simulation of the new servo hydraulic press,optimal control parameters are obtained. Because of the signal delay, nonlinear change ofhydraulic system and the influence of the changes of load condition, position precision ofmoving beam can’t be guaranteed using the conventional PID control, then fuzzy PIDcontrol is adopted in position control system of the new servo hydraulic press, andsimulation analysis is implemented with Simulink control toolbox and fuzzy logic controltoolbox of MATLAB software.