Patent ID: 8393264

Claim:
A press machine comprising: a cushion shaft connected to a lower die; a press shaft connected to an upper die and configured to press a workpiece between the upper die and the lower die in cooperation with the cushion shaft; a motor configured to drive the upper die; and a motor control device configured to control the motor and comprising: a disturbance observer configured to calculate an estimated disturbance value with respect to the motor based on a torque command and a motor velocity of the motor; and an intrusion detector configured to detect, based on the estimated disturbance value, a state of a foreign object between the press shaft and the cushion shaft, wherein the motor control device is configured to determine an integrated value of an absolute value of the estimated disturbance value, and wherein the motor control device is configured to determine that the foreign object is caught when the integrated value exceeds a set value defined in advance.