JP4874590B2 - Control device and control method for die cushion mechanism - Google Patents

Description

  The present invention relates to a control device and a control method for a die cushion mechanism.

  In a press machine that performs press working such as bending, drawing, and punching, a second die is used with respect to a movable support member (generally referred to as a slide) that supports the first die used for press working during the working operation. It is known to equip a die cushion mechanism as an accessory device that applies a required force (pressure) from the side of a supporting member (generally called a bolster) to be supported. The die cushion mechanism normally closes the mold after directly or indirectly colliding the movable element (generally referred to as a cushion pad) held at a predetermined pressure with the slide (or the first mold) moving in the mold closing direction. The cushion pad is configured to move with the slide while applying force (pressure) to the slide until it reaches the mold opening through (molding). During this time, for example, by pinching the peripheral region of the processed portion of the workpiece material between the cushion pad and the slide, generation of wrinkles of the workpiece material can be prevented.

  In order to improve the accuracy of press working using the die cushion mechanism, it is required that the instructed force (pressure) is stably applied to the slide while the cushion pad moves together with the slide. However, many conventional die cushion mechanisms are driven by an hydraulic / pneumatic device, and the force (pressure) on the slide can be varied according to the command value in response to sudden pressure fluctuations due to external causes such as slide collisions. It was generally difficult to control automatically. Therefore, in recent years, a die cushion mechanism using a servomotor as a drive source has been developed to enable force control with excellent responsiveness (see, for example, Patent Document 1).

  The die cushion mechanism described in Patent Document 1 has a configuration in which a cushion pad installed below a slide of a press machine is moved up and down by a servo motor in response to the lifting and lowering operation of the slide. While the slide is lowered, the servo motor operates by position control based on the position command value of the cushion pad to position the cushion pad at a predetermined standby position before the slide applies a collision force to the cushion pad. After the slide applies a collision force to the cushion pad, the servo motor operates by force control based on a predetermined force command value corresponding to the position of the cushion pad, and moves the cushion pad together with the slide. Adjust the force (pressure) applied to the slide from the cushion pad. The collision and pressure are detected by detecting a load applied to the output shaft of the servo motor via the cushion pad.

  On the other hand, in particular for large press machines, in order to reduce equipment costs and installation floor space, instead of using a single large die cushion mechanism, combine multiple relatively small die cushion mechanisms. The configuration used is known. Conventionally, this type of dual die cushion mechanism is generally configured to drive a plurality of cushion pads arranged in parallel in synchronization by an hydraulic / pneumatic device. Therefore, the conventional press machine equipped with the double die cushion mechanism has a problem inferior in control response of each die cushion mechanism as described above.

Japanese Patent Laid-Open No. 10-202327

  A configuration using a servo motor as a drive source as described in Patent Document 1 can be applied to the above-described double die cushion mechanism. In this case, it is possible to adopt a configuration in which the operation of a plurality of cushion pads arranged in parallel is controlled by a plurality of servo motors individually prepared for one slide of the press machine. However, in the configuration in which such a plurality of servo motors are individually controlled according to the conventional method, due to the shape of the press machine and the structure of the opening / closing mechanism, the plurality of die cushion mechanisms have a uniform force on the slide. It may be difficult to generate (pressure). If there are variations in the force of the plurality of die cushion mechanisms, there is a concern that the cushion pads may mediate sliding and adversely affect each other's operation. In particular, when the generated force is large, there is a concern that the mutual interference of such cushion pad movements may increase, resulting in low-frequency vibrations. In order to avoid these disadvantages, it is effective to lower the gain of the force (pressure) control loop in the control system of the individual die cushion mechanism. However, when it is necessary to improve the response of the force control as described above, it is not preferable to reduce the gain of the force control loop.

  An object of the present invention is a control device that controls the operation of a plurality of die cushion mechanisms that generate a force for each slide of a press machine by using a servo motor as a drive source, and has been described above when performing force control. An object of the present invention is to provide a control device capable of solving various problems and generating a required force in each die cushion mechanism with high responsiveness and high accuracy.

  Another object of the present invention is a control method for controlling the operation of a plurality of die cushion mechanisms that generate a force for each slide of a press machine using a servo motor as a driving source. An object of the present invention is to provide a control method capable of solving the above-described problems and generating a required force in each die cushion mechanism with high responsiveness and high accuracy.

In order to achieve the above object, the invention described in claim 1 is a control device that controls the operation of a plurality of die cushion mechanisms that generate a force for each slide of a press machine using a servo motor as a drive source. A force command unit that commands the force generated by the two die cushion mechanisms, two force detection units that individually detect the force generated by the two die cushion mechanisms, and a force commanded by the force command unit Based on the command value and the two force detection values detected by the two force detection units, two speed command units for individually outputting speed command values to the respective servo motors of the two die cushion mechanisms, Two speed detection units that individually detect the operating speed of each servo motor of the die cushion mechanism, two speed command values commanded by the two speed command units, and two speed detection values detected by the two speed detection units Based on the degree detection value, two torque command units that individually output torque command values to the respective servo motors of the two die cushion mechanisms and two force detection values detected by the two force detection units are the same Torque for correcting the two torque command values output by the two torque command units so that the difference between the two force detection values obtained by the force difference calculation unit and the force difference calculation unit for obtaining the difference in time is converged to zero A correction unit, wherein the torque correction unit calculates a correction torque that converges the difference between the two force detection values to zero, and corrects each of the two torque command values using the correction torque. A control device is provided.

The invention according to claim 2, in the control apparatus according to claim 1, the torque correction unit includes a proportional differentials multiplied by the first gain to the hidden two force detection value, of the two force detection value Provided is a control device that uses a sum of an integral range obtained by multiplying an integral value of a range and a second gain as a correction torque.

According to a third aspect of the present invention, there is provided a control device for controlling the operation of a plurality of die cushion mechanisms that generate a force for each slide of a press machine using a servo motor as a drive source. A force command unit that commands the force to be generated, two force detection units that individually detect the forces generated by the two die cushion mechanisms, a force command value commanded by the force command unit, and two force detection units Based on the two detected force values, two speed command units that individually output speed command values to the servo motors of the two die cushion mechanisms and servo motors of the two die cushion mechanisms Based on two speed detection units that individually detect the operation speed, two speed command values commanded by the two speed command units, and two speed detection values detected by the two speed detection units. Two torque command units that individually output torque command values to each servo motor of the cushion mechanism, and a speed difference calculation unit that calculates a difference at the same time between two speed detection values detected by the two speed detection units. And a torque correction unit for correcting two torque command values output by the two torque command units so as to converge the difference between the two speed detection values obtained by the speed range calculation unit to zero, The control unit calculates a correction torque for converging the difference between the two detected speed values to zero, and corrects each of the two torque command values using the correction torque.

Invention according to claim 4, in the control apparatus according to claim 3, the torque correction unit includes a proportional differentials multiplied by the first gain to the hidden two speed detected value, of the two speed detection value Provided is a control device that uses a sum of an integral range obtained by multiplying an integral value of a range and a second gain as a correction torque.

The invention according to claim 5 is a control method for controlling the operation of a plurality of die cushion mechanisms that generate a force for each slide of a press machine by using a servo motor as a drive source. The force command value relating to the force to be generated is obtained, two force detection values relating to the forces generated by the two die cushion mechanisms are obtained, and the two die cushions are based on the force command value and the two force detection values. Obtain two speed command values for each servo motor of the mechanism, obtain two speed detection values for the operating speed of each servo motor of the two die cushion mechanisms, find two speed command values and two speed detection values Based on the above, obtain two torque command values for each servo motor of the two die cushion mechanisms, and find the difference between the two force detection values at the same time It calculates a correction torque for converging the hidden two force detection value to zero, by using the correction torque, to provide a control method and correcting each of the two torque command value.

The invention according to claim 6 is a control method for controlling the operation of a plurality of die cushion mechanisms that generate a force for each slide of a press machine using a servo motor as a drive source. The force command value relating to the force to be generated is obtained, two force detection values relating to the forces generated by the two die cushion mechanisms are obtained, and the two die cushions are based on the force command value and the two force detection values. Obtain two speed command values for each servo motor of the mechanism, obtain two speed detection values for the operating speed of each servo motor of the two die cushion mechanisms, find two speed command values and two speed detection values Based on the above, the two torque command values for the servo motors of the two die cushion mechanisms are obtained, and the difference between the two speed detection values at the same time is obtained. , And calculates the correction torque for converging the hidden two speed detection value to zero, by using the correction torque, to provide a control method and correcting each of the two torque command value.

According to the first aspect of the present invention, due to the shape of the press machine and the structure of the opening / closing mechanism, the two servomotors are simply controlled individually and the uniform force is applied to the two die cushion mechanisms. Even when it is difficult to generate (pressure), by controlling each servo motor using the torque command value corrected by the torque correction unit, it is actually generated in each die cushion mechanism. It is possible to converge the difference between the detected force values of the force to zero, that is, to generate a uniform force in the two die cushion mechanisms. As a result, even when the force generated by each die cushion mechanism is relatively large, the mutual interference of the operation of the die cushion mechanism and the accompanying low-frequency vibrations can be achieved without reducing the gain of each force (pressure) control loop. Occurrence can be prevented in advance, so that the required force can be generated in each die cushion mechanism with high response and high accuracy.

Further , the torque command value can be stably corrected with the correction torque.

According to the second aspect of the invention, the accuracy of the correction torque is improved.

According to the third aspect of the invention, due to the shape of the press machine and the structure of the opening / closing mechanism, the two servomotors are simply controlled individually and the uniform force is applied to the two die cushion mechanisms. Even when it is difficult to generate (pressure), by controlling each servo motor using the torque command value corrected by the torque correction unit, each die cushion mechanism can actually apply force. The difference in the speed detection value of the generated servo motor can be converged to zero, and as a result, a uniform force can be generated in the two die cushion mechanisms. As a result, even when the force generated by each die cushion mechanism is relatively large, the mutual interference of the operation of the die cushion mechanism and the accompanying low-frequency vibrations can be achieved without reducing the gain of each force (pressure) control loop. Occurrence can be prevented in advance, so that the required force can be generated in each die cushion mechanism with high response and high accuracy.

Further , the torque command value can be stably corrected with the correction torque.

According to the invention of claim 4 , the accuracy of the correction torque is improved.

According to the invention described in claim 5 , the same effect as that of the invention described in claim 1 can be obtained.

According to the invention described in claim 6 , the same effect as that of the invention described in claim 3 can be obtained.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Corresponding components are denoted by common reference symbols throughout the drawings.
Referring to the drawings, FIG. 1 is a functional block diagram showing a basic configuration of a control device 10 according to a first aspect of the present invention, and FIG. 2 is a press machine equipped with a plurality of die cushion mechanisms 12 including the control device 10. FIG.

  As shown in FIGS. 1 and 2, the control device 10 according to the first aspect of the present invention includes a plurality of die cushion mechanisms 12 that generate a force with a servo motor 16 as a driving source for each slide 14 of a press machine. It controls the operation. 1 shows two die cushion mechanisms 12 and FIG. 2 shows three die cushion mechanisms 12. However, the present invention is also applicable to a press machine having four or more die cushion mechanisms 12. It goes without saying that the control device 10 can be applied.

Controller 10 includes a force commanding section 18 for commanding a force F to cause the two die cushion mechanism 12, the two force detecting section for detecting a force F of two die cushion mechanism 12 occurs individually 20 and the force command value CF commanded by the force command unit 18 and the two force detection values DF detected by the two force detection units 20, the two die cushion mechanisms 12 are respectively applied to the servo motors 16. two speed commander 22 for outputting a speed command value CS separately, the two speed detecting section 24 for detecting the operating speed S of the respective servo motors 16 of the two die cushion mechanism 12 separately, 2 Based on the two speed command values CS commanded by the two speed command units 22 and the two speed detection values DS detected by the two speed detection units 24, the respective servo motors 16 of the two die cushion mechanisms 12 are used. To Toru Two torque command section 26 for outputting a command value CT separately, the two force detecting section 20 has two force detection value DF detected, a force hidden arithmetic unit 28 for obtaining the hidden RF in the same time, as the force hidden calculating section 28 is converged to zero hidden RF two force detection value DF obtained, the torque correction unit 30 in which two of the torque command unit 26 corrects the two torque command value CT for outputting And is configured.

Individual die cushion mechanism 12 incorporated into the press machine, a cushion pad 32 that moves in response to operation of the slide 1 4, comprising respectively a servo motor 16 for driving the cushion pad 32, the control of the control unit 10 operating the servo motor 16 under, causing correlative pressure (i.e., force F) between the individual cushion pad 32 and the slide 1 4. Slide 1 4, supports the first mold used for press working (not shown), to a second mold which is supported on the unillustrated bolster (not shown), at a speed V required for the press work Move in the direction of approaching or leaving. The cushion pad 32 of each die cushion mechanism 12 is disposed in association with the second mold, and is connected to the output shaft of the servo motor 16 via the ball screw device 34. Slide 1 4 (or the first mold), while moving the mold closing direction, it impinges directly or indirectly to the cushion pad 32 waiting at a predetermined position. And usually, until the mold is opened through the mold closed (molding), the individual cushion pad 32 moves together with the slide 1 4 while applying a predetermined force (pressure) F to the slide 1 4.

The force detector 20 can have a known force (pressure) sensor, and the speed detector 24 can have a known encoder. In the case of using a speed feedback of the slide 1 4 In the force control of each die cushion mechanism 12 may be equipped with a known linear scale as a slide speed detector 36.

Thus, in the control device 10 according to the present invention, the two force detection values DF detected by each of the two die cushion mechanisms 12 are obtained by the functions of the force difference calculation unit 28 and the torque correction unit 30. The two torque command values CT commanded to the servomotors 16 of the individual die cushion mechanisms 12 are corrected so that the range RF at the same time converges to zero. Therefore, due to the structure of the press machine type of shape and the opening and closing mechanism, the simple individual control to method two servo motors 16 to cause uniform force (pressure) on the two die cushion mechanism 12 Even when it is difficult to control the individual servomotors 16 using the corrected torque command value CT, the force detection value DF of the force F actually generated in each die cushion mechanism 12 is controlled. Can be converged to zero, that is, a uniform force F can be generated in the two die cushion mechanisms 12. As a result, according to the control device 10, even when the force F generated in each die cushion mechanism 12 is relatively large, the operation of the cushion pad 32 is performed without reducing the gain of each force (pressure) control loop. Thus, it is possible to prevent the occurrence of the mutual interference and the accompanying low frequency vibration, so that the required force F can be generated in each die cushion mechanism 12 with high responsiveness and high accuracy.

If the configuration of the control device 10 described above is described as a control method, this control method includes a step of obtaining a force command value CF regarding the force F generated in the two die cushion mechanisms 12, and the two die cushion mechanisms 12 Based on the step of obtaining two force detection values DF relating to the force F generated in each, the force command value CF and the two force detection values DF, the two die cushion mechanisms 12 to the respective servo motors 16 A step of obtaining two speed command values CS, a step of obtaining two speed detection values DS related to the operating speed S of the servo motors 16 of the two die cushion mechanisms 12, and two speed command values CS and based on the two velocity detection value DS, obtaining two torque command value CT to the respective servo motors 16 of the two die cushion mechanism 12 stearyl Step of correcting the flop, determining a hidden RF in the same time the two force detection value DF, the hidden RF two force detection value DF to converge to zero, the two torque command value CT And have. By executing such a control method, the above-described special effects are exhibited.

  FIG. 3 shows the control device 40 according to the first embodiment of the present invention. The control device 40 has the basic configuration of the control device 10 described above, and corresponding constituent elements are denoted by common reference numerals and description thereof is omitted.

The control device 40 shown in FIG. 3, the torque correction unit 30, a hidden RF two force detection value DF of the force hidden arithmetic unit 28 calculated, to calculate the correction torque TA to converge to zero, the two A process of adding the calculated correction torque TA to each of the two torque command values CT output from the torque command unit 26 is performed. Thereby, the operation of the two servo motors 16 is individually controlled in accordance with the corrected torque command (CT + TA). Here, the force difference calculation unit 28 and the torque correction unit 30 may be regarded as the vibration suppression controller 42 in consideration of their functions.

In the control system of each die cushion mechanism 12 in the control device 40, the corrected torque command (C _T + T _A ) is converted into a current command via the current command block 44 as shown in the figure, and the servo motor 16 is input. Further, in order to slide 14 (FIG. 2) performs the position control prior to impinging on the cushion pad 32, and the speed command value C _S from the speed command section 22 of the force control loop, the speed command from the position control block 46 Are switched appropriately in the switching device 48.

  FIG. 4 is a functional block diagram showing a basic configuration of the control device 50 according to the second aspect of the present invention, and FIG. 5 is a schematic configuration of a press machine equipped with a plurality of die cushion mechanisms 12 including the control device 50. FIG. The control device 50 according to the second aspect is the control device 10 according to the first aspect described above except that the data used for correcting the torque command value at the final stage of the force control for each die cushion mechanism 12 is different. And substantially the same configuration.

As shown in FIGS. 4 and 5, the control device 50 according to the second aspect of the present invention includes a force command unit 52 that commands the force F generated in the two die cushion mechanisms 12, and two die cushion mechanisms. 12, two force detection units 54 that individually detect the force F generated by the force 12, a force command value CF commanded by the force command unit 52, and two force detection values DF detected by the two force detection units 54 the basis, the two die cushion mechanism each of the two speed command portion 56 a speed command value CS outputted individually to the servo motor 16 of the 12, of the respective servo motors 16 of the two die cushion mechanism 12 Two speed detectors 58 that individually detect the operating speed S, two speed command values CS commanded by the two speed commanders 56, and two speed detections detected by the two speed detectors 58 based on the value DS, two Daiku' ® Each of down mechanism 12 and the two torque command section 60 for outputting separately a torque command value CT to the servo motor 16, the two speed detection value DS two speed detector 58 detects the same Two torque command units 60 output so that the difference RS between the two speed detection values DS obtained by the speed difference calculation unit 62 and the speed difference calculation unit 62 for obtaining the difference RS at the time converges to zero 2 And a torque correction unit 64 that corrects one torque command value CT.

  The press machine (FIG. 5) equipped with the control device 50 described above has substantially the same configuration as the press machine shown in FIG. 2 except for the configuration of the control device 50. Accordingly, corresponding constituent elements are denoted by common reference numerals and description thereof is omitted.

The control apparatus 50 having the above structure, the function of speed hidden calculating unit 62 and the torque correction unit 64, the two speed detection value DS detected by each of the two die cushion mechanism 12, hidden in the same time The two torque command values CT commanded to the servo motors 16 of the individual die cushion mechanisms 12 are corrected so that RS converges to zero. Therefore, due to the structure of the press machine type of shape and the opening and closing mechanism, the simple individual control to method two servo motors 16 to cause uniform force (pressure) on the two die cushion mechanism 12 Even in a case where it is difficult to control the servomotors 16 using the corrected torque command value CT, the servomotors 16 that actually generate the force F in the respective die cushion mechanisms 12 are controlled. The range RS of the speed detection values DS can be converged to zero, and as a result, a uniform force F can be generated in the two die cushion mechanisms 12. As described above, according to the control device 10, even when the force F generated in each die cushion mechanism 12 is relatively large, the cushion pad 32 can be controlled without reducing the gain of each force (pressure) control loop. It is possible to prevent the mutual interference of the operation and the generation of the low frequency vibration accompanying the operation. Therefore, the required force F can be generated in each die cushion mechanism 12 with high responsiveness and high accuracy.

If the configuration of the control device 50 described above is described as a control method, this control method includes a step of obtaining a force command value CF relating to the force F generated in the two die cushion mechanisms 12, and the two die cushion mechanisms 12 Based on the step of obtaining two force detection values DF relating to the force F generated in each, the force command value CF and the two force detection values DF, the two die cushion mechanisms 12 to the respective servo motors 16 A step of obtaining two speed command values CS, a step of obtaining two speed detection values DS related to the operating speed S of the servo motors 16 of the two die cushion mechanisms 12, and two speed command values CS and based on the two velocity detection value DS, obtaining two torque command value CT to the respective servo motors 16 of the two die cushion mechanism 12 stearyl And flop, determining a hidden RS at the same time the two velocity detection value DS, so as to converge the hidden RS to zero at the same time the two velocity detection value DS, two torque command value CT Correcting. By executing such a control method, the above-described special effects are exhibited.

  FIG. 6 shows a control device 70 according to a second embodiment of the present invention. The control device 70 has the basic configuration of the control device 50 described above, and corresponding components are denoted by common reference numerals and description thereof is omitted.

The control device 70 shown in FIG. 6, the torque correction unit 64, a hidden RS two speed detection value DS speed hidden calculating unit 62 is calculated, to calculate the correction torque TB for converging to zero, the two A process of adding the calculated correction torque TB to each of the two torque command values CT output from the torque command unit 60 is performed. Thereby, the operations of the two servo motors 16 are individually controlled in accordance with the corrected torque command (CT + TB). Here, the speed difference calculation unit 62 and the torque correction unit 64 can be regarded as the vibration suppression controller 72 in consideration of their functions.

In the control system of each die cushion mechanism 12 in the control device 70, as shown in the figure, the corrected torque command (C _T + T _B ) is converted into a current command via the current command block 74, and the servo motor 16 is input. Further, in order to slide 14 (FIG. 5) performs the position control prior to impinging on the cushion pad 32, and the speed command value C _S from the speed command section 56 of the force control loop, the speed command from the position control block 76 Are appropriately switched in the switching device 78.

In the control devices 10 and 40 according to the present invention described above, the torque correction unit 30 obtains the correction torque TA by multiplying the difference RF between the two force detection values DF obtained by the force difference calculation unit 28 by a gain. Can do. Alternatively, as illustrated in FIG. 7A, the torque correction unit 30 may include a proportional difference RFP obtained by multiplying the difference RF between the two force detection values DF obtained by the force difference calculation unit 28 by the first gain 80, 2 The sum of the integral value RFI obtained by multiplying the integral value of the difference RF of the two force detection values DF by the second gain 82 may be used as the correction torque TA. By using the integral element in this way, the accuracy of the correction torque TA is improved.

Similarly, in the control devices 50 and 70 according to the present invention described above, the torque correction unit 64 multiplies the difference RS between the two speed detection values DS obtained by the speed difference calculation unit 62 by a gain, thereby correcting the correction torque TB. Can be requested. Alternatively, as illustrated in FIG. 7B, the torque correction unit 64 includes a proportional difference RSP obtained by multiplying the difference RS between the two speed detection values DS obtained by the speed difference calculation unit 62 by the first gain 84, 2 A sum of the integral value RSI obtained by multiplying the integral value of the difference RS of the two speed detection values DS by the second gain 86 may be used as the correction torque TB. By using the integral element in this way, the accuracy of the correction torque TB is improved.

It is a functional block diagram which shows the basic composition of the control apparatus of the die cushion mechanism which concerns on the 1st aspect of this invention. It is a figure which shows typically the structure of the press machine carrying the some die cushion mechanism provided with the control apparatus of FIG. It is a block diagram of the control system of the control apparatus by the 1st Embodiment of this invention. It is a functional block diagram which shows the basic composition of the control apparatus of the die cushion mechanism which concerns on the 2nd aspect of this invention. It is a figure which shows typically the structure of the press machine carrying the some die cushion mechanism provided with the control apparatus of FIG. It is a block diagram of the control system of the control apparatus by the 2nd Embodiment of this invention. (A) The block diagram which shows a part of control system by the modification of a 1st aspect, (b) The block diagram which shows a part of control system by the modification of a 2nd aspect.

Explanation of symbols

10, 40, 50, 70 Control device 12 Die cushion mechanism 14 Slide 16 Servo motor 18, 52 Force command unit 20, 54 Force detection unit 22, 56 Speed command unit 24, 58 Speed detection unit 26, 60 Torque command unit 28 Force Range calculation unit 30, 64 Torque correction unit 32 Cushion pad 62 Speed range calculation unit 80, 84 First gain 82, 86 Second gain

Claims (6)

A control device for controlling the operation of a plurality of die cushion mechanisms that generate a force for each slide of a press machine using a servo motor as a drive source,
A force command unit that commands the force generated in the two die cushion mechanisms;
Two force detectors for individually detecting the forces generated by the two die cushion mechanisms;
Based on the force command value commanded by the force command unit and the two force detection values detected by the two force detection units, the speed command values to the servo motors of the two die cushion mechanisms are individually output. Two speed command units to
Two speed detectors for individually detecting the operating speeds of the servo motors of the two die cushion mechanisms;
Torque commands to the servo motors of the two die cushion mechanisms based on the two speed command values commanded by the two speed command units and the two speed detection values detected by the two speed detection units. Two torque command units that individually output values,
A force difference calculation unit for obtaining a difference between the two force detection values detected by the two force detection units at the same time;
A torque correction unit for correcting the two torque command values output by the two torque command units so as to converge the range of the two force detection values obtained by the force range calculation unit to zero;
Comprising
The torque correction unit calculates a correction torque for converging the difference between the two force detection values to zero, and corrects each of the two torque command values using the correction torque;
A control device characterized by.   The torque correction unit is a sum of a proportional difference obtained by multiplying the difference between the two force detection values by a first gain and an integral difference obtained by multiplying an integral value of the difference between the two force detection values by a second gain. The control device according to claim 1, wherein the control torque is the correction torque. A control device for controlling the operation of a plurality of die cushion mechanisms that generate a force for each slide of a press machine using a servo motor as a drive source,
A force command unit that commands the force generated in the two die cushion mechanisms;
Two force detectors for individually detecting the forces generated by the two die cushion mechanisms;
Based on the force command value commanded by the force command unit and the two force detection values detected by the two force detection units, the speed command values to the servo motors of the two die cushion mechanisms are individually output. Two speed command units to
Two speed detectors for individually detecting the operating speeds of the servo motors of the two die cushion mechanisms;
Torque commands to the servo motors of the two die cushion mechanisms based on the two speed command values commanded by the two speed command units and the two speed detection values detected by the two speed detection units. Two torque command units that individually output values,
A speed difference calculation unit for obtaining a difference between the two speed detection values detected by the two speed detection units at the same time;
A torque correction unit that corrects the two torque command values output by the two torque command units so as to converge the range of the two speed detection values obtained by the speed range calculation unit to zero;
Comprising
The torque correction unit calculates a correction torque for converging the difference between the two speed detection values to zero, and corrects each of the two torque command values using the correction torque;
A control device characterized by.   The torque correction unit is a sum of a proportional difference obtained by multiplying the difference between the two speed detection values by a first gain and an integral difference obtained by multiplying an integral value of the difference between the two speed detection values by a second gain. The control device according to claim 3, wherein the control torque is the correction torque. A control method for controlling the operation of a plurality of die cushion mechanisms that generate a force for each slide of a press machine using a servo motor as a drive source,
Obtaining a force command value relating to the force generated in the two die cushion mechanisms;
Obtain two force detection values related to the force generated by each of the two die cushion mechanisms,
Based on the force command value and the two force detection values, two speed command values for the servo motors of the two die cushion mechanisms are obtained,
Obtain two speed detection values related to the operating speed of the servo motor of each of the two die cushion mechanisms;
Based on the two speed command values and the two speed detection values, two torque command values for the servo motors of the two die cushion mechanisms are obtained,
The difference between the two force detection values at the same time is obtained,
Calculating a correction torque for converging the range of the two force detection values to zero, and correcting each of the two torque command values using the correction torque;
A control method characterized by the above. A control method for controlling the operation of a plurality of die cushion mechanisms that generate a force for each slide of a press machine using a servo motor as a drive source,
Obtaining a force command value relating to the force generated in the two die cushion mechanisms;
Obtain two force detection values related to the force generated by each of the two die cushion mechanisms,
Based on the force command value and the two force detection values, two speed command values for the servo motors of the two die cushion mechanisms are obtained,
Obtain two speed detection values related to the operating speed of the servo motor of each of the two die cushion mechanisms;
Based on the two speed command values and the two speed detection values, two torque command values for the servo motors of the two die cushion mechanisms are obtained,
The difference between the two speed detection values at the same time is obtained,
Calculating a correction torque for converging the difference between the two speed detection values to zero, and correcting each of the two torque command values using the correction torque;
A control method characterized by the above.

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