US Patent 7905126 Die cushion controller of press machine

A die-cushion controlling device includes a position-command-signal outputting section for outputting a position command signal of a die-cushion pad; a position detecting section for detecting a position of the die-cushion pad; a position comparing section for outputting a position deviation signal corresponding to a deviation between a target position value based on the position command signal and a position detection value based on a position detection signal; a position controlling section for outputting a position-speed command signal based on the position deviation signal; a speed controlling section for outputting a motor-current command signal based on the position-speed command signal; a servo amplifier for generating a current corresponding to the motor-current command signal; and an escape-position-command-signal outputting section for outputting a position command signal for commanding the die-cushion pad to escape from a bottom dead center position based on a press signal outputted when a slide has reached a bottom dead center.