Press machine controller

A press machine controller for controlling a press machine having first and second servo motors to drive a slide via first and second reduction mechanisms, respectively, adapted to be changed in reduction ratio in accordance with a position of the slide, comprising:

• a first command generator for generating at least one of a position command, a speed command and a torque command for the first servo motor;
• a second command generator for generating at least one of a position command, a speed command and a torque command for the second servo motor;
• a vibration command generator for generating a vibration command, which is enough to change a situation in which static friction works to a situation in which a dynamic friction works, based on a parameter preset for the press machine controller;
• a slide position detector for detecting the position of the slide;
• a first vibration command adding portion for adding the vibration command to any one of the position command, the speed command and the torque command for the first servo motor in a case where the slide position detected by the slide position detector is in a predetermined range;
• and
• a second vibration command adding portion for adding the vibration command to any one of the position command, the speed command and the torque command for the second servo motor in a case where the stopped slide position detected by the slide position detector is in the predetermined range including a bottom dead center of the slide;
• wherein the vibration command added by the first vibration command adding portion is in phase with the vibration command added by the second vibration command adding portion and wherein the torque, required for restarting the press machine after the slide stops at the bottom dead center thereof or in the vicinity of the bottom dead center, becomes small.

A press machine controller for controlling a press machine having a servo motor to drive a slide via a reduction mechanism adapted to be changed in reduction ratio in accordance with a position of the slide, comprising:

• a command generator for generating at least one of a position command, a speed command and a torque command for the servo motor;
• a vibration command generator for generating a vibration command, which is enough to change a situation in which a dynamic friction works, based on a parameter preset for the press machine controller;
• a slide position detector for detecting the position of the slide;
• a vibration adding signal detector for detecting an input of a vibration adding signal permitting an addition of the vibration command when the slide, the position thereof is detected by the slide position detector, stops at the bottom dead center of the slide or in the vicinity of the bottom dead center;
• and
• a vibration command adding portion for adding the vibration command to any one of the position command, the speed command and the torque command for the servo motor in the case where the vibration adding signal is input and wherein the torque, required for restarting the press machine after the slide stops at the bottom dead center thereof or in the vicinity of the bottom dead center, becomes small.

A press machine controller for controlling a press machine having first and second servo motors for driving a slide via first and second reduction mechanisms, respectively, adapted to be changed in reduction ratio in accordance with a position of the slide, comprising:

• a first command generator for generating at least one of a position command, a speed command and a torque command for the first servo motor;
• a second command generator for generating at least one of a position command, a speed command and a torque command for the second servo motor;
• a vibration command generator for generating a vibration command, which is enough to change a situation in which static friction works to a situation in which a dynamic friction works, based on a parameter preset for the press machine controller;
• a slide position detector for detecting the position of the slide;
• a vibration adding signal detector for detecting an input of a vibration adding signal permitting an addition of the vibration command when the slide, the position thereof is detected by the slide position detector, stops at the bottom dead center of the slide or in the vicinity of the bottom dead center;
• a first vibration command adding portion for adding the vibration command to any one of the position command, the speed command and the torque command for the first servo motor in a case where the vibration adding signal is input;
• and
• a second vibration command adding portion for adding the vibration command to any one of the position command, the speed command and the torque command for the second servo motor in a case where the vibration adding signal is input;
• wherein the vibration command added by the first vibration command adding portion is in phase with the vibration command added by the second vibration command adding portion and wherein the torque, required for restarting the press machine after the slide stops at the bottom dead center thereof or in the vicinity of the bottom dead center, becomes small.