Patent ID: 7144238

Claim:
A servo motor control apparatus for electric injection molding machine, comprising: a motion control unit, for generating a speed command; a first drive amplifier connected to the motion control unit, for receiving the speed command of the motion control unit to drive a first servo motor, allowing the first drive amplifier, the motion control unit and the first servo motor to cooperatively form a first position control loop; and at least one second drive amplifier connected to the motion control unit, for receiving the speed command of the motion control unit to drive at least one second servo motor, allowing the second drive amplifier, the motion control unit and said second servo motor to cooperatively form a second position control loop; wherein the motion control unit comprises at least one synchronous controller for producing a speed feed forward compensation and a torque feed forward compensation obtained from a difference between a position error of the first position control loop and a position error of the second position control loop, allowing the synchronous controller to use the speed feed forward compensation and a torque feed forward compensation to adjust the second servo motor and to keep the second servo motor synchronous in rotation speed with the first servo motor.