Controller for die cushion mechanism

A controller for a die cushion mechanism that generates force on a slide of a pressing machine using a servo motor as a driving source, the controller comprising:

• a spring element that is displaced according to a force between the die cushion mechanism and the slide;
• a force instructor that instructs force to be generated between the die cushion mechanism and the slide;
• a force detector that detects force generated between the die cushion mechanism and the slide;
• and
• a speed instruction generator that generates a speed instruction of the servo motor, based on a force instruction value instructed by the force instructor and a force detection value detected by the force detector, wherein
• the speed instruction generator generates the speed instruction, by adding a product of an integration value of a force difference and a second force gain to a product of the force difference and a first force gain, the force difference being determined from a difference between the force instruction value and the force detection value, and
• the speed instruction generator changes either one of or both the first force gain and the second force gain, based on a spring constant corresponding value of the spring element determined from a force indicator that works between the slide and the die cushion.

A controller for a die cushion mechanism that generates force on a slide of a pressing machine using a servo motor as a driving source, the controller comprising:

• a spring element that is displaced according to a force between the die cushion mechanism and the slide;
• a force instructor that instructs force to be generated between the die cushion mechanism and the slide;
• a force detector that detects force generated between the die cushion mechanism and the slide;
• a speed instruction generator that generates a speed instruction of the servo motor, based on a force instruction value instructed by the force instructor and a force detection value detected by the force detector;
• a speed detector that detects a speed of the servo motor;
• and
• a current instruction generator that generates a current instruction of the servo motor, based on a speed instruction value instructed by the speed instruction generator and a speed detection value detected by the speed detector, wherein
• the current instruction generator generates the current instruction by multiplying a speed gain to a speed difference determined from a difference between the speed instruction value and the speed detection value, and
• the speed instruction generator changes the speed gain, based on a spring constant corresponding value of the spring element determined from a force indicator that works between the slide and the die cushion.

A controller for a die cushion mechanism that generates force on a slide of a pressing machine using a servo motor as a driving source, the controller comprising:

• a spring element that is displaced according to a force between the die cushion mechanism and the slide;
• a force instructor that instructs force to be generated between the die cushion mechanism and the slide;
• a force detector that detects force generated between the die cushion mechanism and the slide;
• a speed instruction generator that generates a speed instruction of the servo motor, based on a force instruction value instructed by the force instructor and a force detection value detected by the force detector;
• a speed detector that detects a speed of the servo motor;
• and
• a current instruction generator that generates a current instruction of the servo motor, based on a speed instruction value instructed by the speed instruction generator and a speed detection value detected by the speed detector, wherein
• the current instruction generator generates the current instruction by adding a product of an integration value of a speed difference and a second speed gain to a product of the speed difference and a first speed gain, the speed difference being determined from a difference between the speed instruction value and the speed detection value, and
• the speed instruction generator changes either one of or both the first speed gain and the second speed gain, based on a spring constant corresponding value of the spring element determined from a force indicator that works between the slide and the die cushion.