Abstract: A fuzzy coordination control method was proposed based on pump selfpriming ability decline inflection point. Pump switch was designed on the base of the minimum speed of the variable hydraulic pump. According to the actual characteristics of the system, Stype function was got by the choice of the transformation of normal function. To determine the role of the different error domain controller strength, error universe point discrete way was used to deal with the choice of the membership function. Due to the uncertainty of the system parameters and load parameters, fuzzy control method was used to overcome the difficulty in establishment of the model, better dynamic characteristics was obtained. Simulation and experiments show that this method can solve the problems of lowspeed characteristics.

Key words: injection moldding machine, fuzzy control, servo motor, variable pump, fuzzy coordination control