# US 7,461,530 B2 · Die cushion mechanism, and apparatus and method for controlling the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,461,530 B2 - Document ID: US7461530B2 - Status: Granted - Kind: B2 - Application number: 11/265,078 - Filed: 2005-11-03 - Published: 2006-05-04 - Granted: 2008-12-09 - Earliest claimed: 2004-11-04 - Assignees: Fanuc Corporation - Inventors: Yasusuke Iwashita; Tadashi Okita; Hiroyuki Kawamura; Satoshi Ikai - Web page: https://patentgrep.com/patent/US7461530B2 ## CPC - G05B 19/19: characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path - B21D 24/02: Die-cushions - G05B 2219/41139: Compensate dynamic deflection of slide, calculated with position, speed, torque deflection values - G05B 2219/42087: Speed and force loop - G05B 2219/45131: Turret punch press - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) - B21D: WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL (working or processing of wire B21F) ## Abstract A control apparatus for controlling a die cushion mechanism including a servo-motor as a drive source and producing a force adapted to be applied to a slide in a press machine. The control apparatus includes a force commanding section for commanding a force to be produced by the die cushion mechanism; a force detecting section for detecting the force produced by the die cushion mechanism; a motor-speed detecting section for detecting an operating speed of the servo-motor; a slide-speed detecting section for detecting a moving speed of the slide; and a force controlling section for executing a force control on the servo-motor, based on a force command value commanded by the force commanding section, a force detected value detected by the force detecting section, a motor-speed detected value detected by the motor-speed detecting section and a slide-speed detected value detected by the slide-speed detecting section. ## Claims ### Claim 1 A control apparatus for controlling a die cushion mechanism including a servo-motor as a drive source and producing a force adapted to be applied to a slide in a press machine, comprising: a force commanding section for commanding a force to be produced by said die cushion mechanism; a force detecting section for detecting said force produced by said die cushion mechanism; a motor-speed detecting section for detecting an operating speed of said servo-motor; a slide-speed detecting section for detecting a moving speed of said slide; and a force controlling section for executing a force control on said servo-motor, based on a force command value commanded by said force commanding section, a force detected value detected by said force detecting section, a motor-speed detected value detected by said motor-speed detecting section and a slide-speed detected value detected by said slide-speed detecting section. ### Claim 2 (depends on 1) A control apparatus as set forth in claim 1, wherein said force controlling section includes a speed calculating section for calculating, from said force command value and said force detected value, a speed command value to be commanded to said servo-motor, and a speed controlling section for correcting said speed command value calculated by said speed calculating section by using said slide-speed detected value, and controlling said operating speed of said servo-motor based on said speed command value as corrected and said motor-speed detected value. ### Claim 3 (depends on 2) A control apparatus as set forth in claim 2, wherein said speed controlling section corrects said speed command value calculated by said speed calculating section by adding said slide-speed detected value to said speed command value. ### Claim 4 (depends on 1) A control apparatus as set forth in claim 1, wherein said force commanding section includes a time-constant setting section for setting a rise time constant of said force command value; and wherein said force controlling section includes a time-constant adjusting section for adjusting said rise time constant set by said time-constant setting section, based on said slide-speed detected value detected by said slide-speed detecting section, and executes said force control based on said force command value including said rise time constant as adjusted. ### Claim 5 (depends on 4) A control apparatus as set forth in claim 4, wherein said force controlling section includes a speed controlling section for executing a preliminary acceleration control for starting said servo-motor before said die cushion mechanism produces said force and during a period when said slide moves; and wherein said time-constant setting section adjusts said rise time constant, during a period when said speed controlling section executes said preliminary acceleration control, based on said motor-speed detected value detected by said motor-speed detecting section and said slide-speed detected value detected by said slide speed detecting section. ### Claim 6 (depends on 4) A control apparatus as set forth in claim 4, wherein said time-constant adjusting section adjusts said rise time constant based on a difference between said motor-speed detected value and said slide-speed detected value. ### Claim 7 (depends on 6) A control apparatus as set forth in claim 6, wherein said time-constant adjusting section adjusts said rise time constant in such a manner that, as said difference between said motor-speed detected value and said slide-speed detected value becomes large, said rise time constant decreases. ### Claim 8 (depends on 1) A control apparatus as set forth in claim 1, wherein said force controlling section includes a speed controlling section for executing a preliminary acceleration control for starting said servo-motor before said die cushion mechanism produces said force and during a period when said slide moves; wherein said control apparatus further comprises a speed commanding section for commanding a preliminary-speed command value used for said preliminary acceleration control to said speed controlling section; and wherein said speed controlling section adjusts said preliminary-speed command value commanded by said speed commanding section, based on said slide-speed detected value detected by said slide-speed detecting section. ### Claim 9 (depends on 8) A control apparatus as set forth in claim 8, wherein said speed controlling section adjusts said preliminary-speed command value in such a manner that said preliminary-speed command value is proportional to said slide-speed detected value. ### Claim 10 (depends on 1) A die cushion mechanism incorporated into a press machine, comprising: a cushion pad movable in correspondence with a motion of a slide; a servo-motor for driving said cushion pad; a control apparatus for controlling said servo-motor and producing an correlative pressure between said cushion pad and said slide; wherein said control apparatus comprises a control apparatus as described in claim 1. ### Claim 11 A control method for controlling a die cushion mechanism including a servo-motor as a drive source and producing a force adapted to be applied to a slide in a press machine, comprising: determining a force command value regarding a force to be produced by said die cushion mechanism; determining a force detected value regarding a force actually produced by said die cushion mechanism; determining an operating-speed detected value regarding an operating speed of said servo-motor; determining a moving-speed detected value regarding a moving speed of said slide; and executing a force control on said servo-motor, based on said force command value, said force detected value, said operating-speed detected value and said moving-speed detected value. ### Claim 12 (depends on 11) A control method as set forth in claim 11, wherein the step of executing a force control includes calculating, from said force command value and said force detected value, a speed command value to be commanded to said servo-motor, correcting said speed command value by using said moving-speed detected value, and controlling said operating speed of said servo-motor based on said speed command value as corrected and said operating-speed detected value. ### Claim 13 (depends on 12) A control method as set forth in claim 12, wherein said speed command value as calculated is corrected by adding said moving-speed detected value to said speed command value. ### Claim 14 (depends on 11) A control method as set forth in claim 11, wherein the step of executing a force control includes setting a rise time constant of said force command value, and adjusting said rise time constant based on said moving-speed detected value, so as to execute said force control based on said force command value including said rise time constant as adjusted. ### Claim 15 (depends on 14) A control method as set forth in claim 14, wherein a preliminary acceleration control for starting said servo-motor before said die cushion mechanism produces said force and during a period when said slide moves is executed; and wherein said rise time constant is adjusted, during said preliminary acceleration control, based on said operating-speed detected value and said moving-speed detected value. ### Claim 16 (depends on 14) A control method as set forth in claim 14, wherein said rise time constant is adjusted based on a difference between said operating-speed detected value and said moving-speed detected value. ### Claim 17 (depends on 16) A control method as set forth in claim 16, wherein said rise time constant is adjusted in such a manner that, as said difference between said operating-speed detected value and said moving-speed detected value becomes large, said rise time constant decreases. ### Claim 18 (depends on 11) A control method as set forth in claim 11, further comprising executing a preliminary acceleration control for starting said servo-motor before said die cushion mechanism produces said force and during a period when said slide moves, and adjusting a preliminary-speed command value used for said preliminary acceleration control, during said preliminary acceleration control, based on said moving-speed detected value. ### Claim 19 (depends on 18) A control method as set forth in claim 18, wherein said preliminary-speed command value is adjusted in such a manner that said preliminary-speed command value is proportional to said moving-speed detected value.