Patent ID: 6333615
Filing Date: 2001-12-25
Classification: G05B

Abstract:
A synchronization control device for a servo motor comprising:a main spindle and an auxiliary spindle each having a chuck that holds both ends of a workpiece and being coupled to or decoupled from each other through said workpiece;a main servo motor and an auxiliary servo motor which rotationally drive said main spindle and said auxiliary spindle, respectively;a main spindle position detector and an auxiliary spindle position detector which are fitted to said main spindle and said auxiliary spindle, respectively, and output a position feedback signal;a main servo motor speed detector and an auxiliary servo motor speed detector which are fitted to said main servo motor and said auxiliary servo motor, respectively, and output a speed feedback signal;a main servo amplifier and an auxiliary servo amplifier which drive said main servo motor and said auxiliary servo motor, respectively; anda numerical control unit which outputs a speed command and a position command to said main servo amplifier and said auxiliary servo amplifier,wherein each of said main servo amplifier and said auxiliary servo amplifier includes:a position control section which outputs a position droop and the speed command responsive to the position droop on the basis of inputs of the position feedback signal from said position detector and the position command from said numerical control unit;a speed control section which outputs a current command on the basis of the speed command from said position control section and the speed feedback signal from said speed detector; anda current control section which controls a supply current to the motor on the basis of the current command from said speed control section and the current feedback signal which flows in the motor,wherein said auxiliary servo amplifier further includes a position correction section which obtains position correction data based on a difference in position droop between the main spindle position droop and the auxiliary spindle position droop and based on the speed feedback signal from the speed detector of said auxiliary servo motor when said main servo motor and said auxiliary servo motor rotate in a state where said main spindle and said auxiliary spindle are decoupled from each other, andwherein the position control section of said auxiliary servo amplifier adds the position correction data from said position correction section to the position droop and outputs the speed command responsive to the position droop obtained by addition when said main spindle and said auxiliary spindle are coupled to each other through said workpiece, and said main servo motor and said auxiliary servo motor rotate in synchronization with each other.