JPH0369640B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) This invention aims to improve the balance of the press and the pressure applied to the compressed object when compressing an object such as a resin plate using a hydraulic press or the like. The present invention relates to a press control device.

(Conventional technology and its problems) When molding an item using a hydraulic press, etc., the upper mold must be kept in equilibrium after it touches the object to be compressed, such as a resin plate, until the molding is completed. It is important to control the pressure applied to the object to be compressed to be constant in order to manufacture products with uniform reproducibility.

However, with conventional presses that rely on mechanical rigidity, it has been impossible to maintain highly accurate balance within, for example, 0.05 mm, and to keep the actual pressure applied to the compressed object constant.

Therefore, in order to improve the above-mentioned drawbacks,
There is one disclosed in Japanese Patent Application Laid-open No. 60-30323.
This is done by accurately supporting the slide (to which the upper mold is attached) in a balanced manner using a balance support device installed in the bed of the press, and by detecting the support force of the balance support device and comparing it with the standard setting force. When the force is greater than the standard setting force, the descending speed of the slide is slowed down, and when the supporting force is less than the standard setting force, the descending speed of the slide is controlled to be faster, and the slide is controlled to follow without leaving the balance support device. This is a molding method, and the purpose is to maintain the balance of the slide (that is, the upper mold) mentioned above and to keep the pressure applied to the object to be compressed constant.

However, although one of the objectives is to balance the slide in terms of height, it is controlled based on the speed difference of each balance support device, so there are problems with accuracy due to delays in control and the like. Furthermore, since the speed of each balance support device is lowered in synchronization with each other, for example, as shown in Fig. 8 a and b, when the compressed object 1 is biased (Fig. a), the viscosity of the compressed object 1 is lowered. There was a problem in that the balance of the slide shifted depending on the condition of the object to be compressed, such as in the case of different cases (Figure b). In FIG. 8, 2 is an upper mold, 3 is a lower mold, 4 is a slide, and 5 is a pressure cylinder.

In addition, the speed of the pressurizing cylinder is controlled for the other purpose of keeping the pressure applied to the compressed object constant. 2
There will be two control loops in one operating means. In other words, due to the existence of the two control loops, there is a problem in that the effects of the time difference between the two control loops result in a result that undermines the objectives of both loops.

(Objective of the Invention) The purpose of the present invention is to solve the above-mentioned problems of the prior art, to keep the slide accurately balanced in any situation or state of the object to be compressed, and to maintain a constant pressure applied to the object to be compressed. It is an object of the present invention to provide a press control device that can be controlled so as to maintain

(Means for Achieving the Object) In order to achieve the above object, the press control device according to the present invention has the following features: a plurality of control cylinders disposed on the bed to support the slide; a first pressure sensor provided in the pressure cylinder to detect the pressurizing force of the pressure cylinder; and a first pressure sensor provided in each of the control cylinders. a position sensor that detects the height of the control cylinder; a second pressure sensor that is installed in each of the control cylinders and detects the pressure applied to the control cylinder; and a second pressure sensor that detects the pressure applied to the control cylinder; a first comparison means for comparing the heights of the cylinders; a first operation amount determining means for determining the operation amount of each control cylinder based on the comparison result by the first comparison means;
a first control means for controlling each of the control cylinders according to the operation amount by the first operation amount determination means; and a pressurizing force of the pressurizing cylinder obtained from the first pressure sensor and the second pressure. an actual pressurizing force measuring means for measuring the actual pressurizing force based on the difference between the sum of pressures applied to each of the control cylinders obtained by the sensor; and comparing the actual pressurizing force obtained by the actual pressurizing force measuring means and a preset target actual pressurizing force. a second comparison means for determining the operation amount of each of the control cylinders based on a comparison result by the second comparison means; and an operation by the second operation amount determination means. and second control means for controlling the control cylinder according to the amount.

(Embodiment) A Overall configuration and operation of the embodiment Figures 1a and 1b show an embodiment of the press control device according to the present invention, in which a is an explanatory diagram of the three-dimensional configuration of the press device, and b is a cross-sectional configuration of the press device. It is an explanatory diagram.

As shown in the figure, the press device includes an object to be compressed 1
In order to mold the upper mold 2 and lower mold 3,
They are provided at the bottom. A slide 4 is bonded to the upper part of the upper mold 2, and the upper mold 2 can be operated by moving the slide 4 up and down. Further, a pressurizing cylinder 5 is attached to the upper part of the slide 4, and the compressed object 1 is pressed by applying power to the slide 4 by the piston movement of the pressurizing cylinder 5.
Further, the pressurizing cylinder 5 is equipped with a pressure sensor 21, and the pressure sensor 21 detects the pressure of the pressurizing cylinder 5.

On the other hand, the lower mold 3 is fixed on the bed 6. On the bed 6, in addition to the lower mold 3, control cylinders 7 are arranged at the four corners. The control cylinder 7 supports the slide 4 at its upper part. Each control cylinder 7 is equipped with a high speed valve 12 and a servo valve 13. The high speed valve 12 opens and closes at high speed so that the height of the control cylinder 7 can be adjusted in a short time, and the servo valve 13 operates to gradually adjust the pressure applied to the control cylinder. These valves open and close according to signals from the control device 11.

Each control cylinder 7 also has a position sensor 8.
and a pressure sensor 9, and a position sensor 8.
detects the height of each control cylinder 7 (that is, the height of the slide 4 at each corner), and the pressure sensor 9 detects the pressure applied to each control cylinder 7.
The detected height is caused by the pressure of the pressure cylinder 5, and the pressure is caused by the pressure of the pressure cylinder 5.
It changes from time to time due to the reaction force of the object 1 to be compressed.

Each position sensor 8, each pressure sensor 9, and each pressure sensor 21 are connected to an A/D converter 10, and the A/D converter 10 controls each cylinder by detection by the position sensor 8 and pressure sensors 9, 21. 7, the pressure applied to each control cylinder 7, and the pressurizing force of the pressurizing cylinder 5 as input signals, which are digitized. Also, A/
The D converter 10 is connected to the control device 11 and outputs the above-mentioned digital signals of height and pressure to the control device 11.

The control device 11 includes each of the control cylinders 7 described above.
Control is performed by using digital signals of the height and pressure of the pressurizing cylinder 5 as parameters, and sending signals to the high-speed valve 12 and the servo valve 13 according to a control method described later. The high-speed valve 12 opens and closes at high speed and controls the height of each control cylinder 7 to match the height of the slide 4.
maintain equilibrium. At the same time, the servo valve 13 performs pressure control by gradually adjusting the pressure of each control cylinder 7 to the target pressure, and keeps the pressure applied to the compressed object 1 constant. Such control is repeated until pressing of the object 1 to be compressed is completed.

B First embodiment using first control device (B-) Configuration and operation Figure 2 shows the position sensor 8 and pressure sensors 9 and 2.
The height of each control cylinder 7 obtained from 1,
2 is a block diagram showing in detail the configuration of a first control device 11 for performing the above-described control using the pressure applied to each control cylinder 7 and the pressure of the pressure cylinder 5 as parameters. FIG.

In the figure, the height of each control cylinder 7 is
h ₁ to _{h 4} , the pressure applied to each control cylinder 7
_P1 to _P4 , and the pressure of the pressurizing cylinder 5 is _Pn .

In the height control of the control device 11 using the parameters h ₁ to _{h 4} , first the minimum height determining unit 14
, the minimum value h _nio is detected from h ₁ to _{h 4} .
In order to match the height of each control cylinder to this h _nio , the heights of h ₁ to _{h 4} are subtracted by h _nio in the subtraction unit 15, thereby reducing the operation amount δ ₁ to _{δ 4} of each control cylinder 7. obtain. These manipulated variables δ ₁ to _{δ 4} are determined by the proportionality constant R _l in the control law section 16.
The height of each control cylinder 7 is made to match at high speed by multiplying the value by converting it into a control amount and sending a control signal to each high-speed valve 12 to perform height control.

On the other hand, in the pressure control of the first control device 11 using parameters P ₁ to P ₄ , first P ₁
The sum of pressures P of ~ _P4 is determined by the addition unit 17,
In each control _{cylinder target pressure setting unit 18, P′=P n −P s ( Target} pressure _sum ) Set each control cylinder target pressure P ₁ ′ to _{P 4} ′ so that the deviation δP becomes zero when δP=P−P′. Most simply, the deviation δP may be equally distributed among the four control cylinders 7 to determine P ₁ ′ to P ₄ ′. Note that the target actual pressing force _Ps is set in advance according to the material of the object 1 to be compressed.

Each of the above control cylinder target pressures P ₁ ′ to P ₄ ′ and
By calculating the difference between P ₁ to _{P 4} in the subtraction unit 19,
Obtain the manipulated variables ε ₁ to _{ε 4} . These manipulated variables ε ₁ to _{ε 4}
is multiplied by a proportionality constant K _p in the control law section 20 to convert it into a control amount, and by sending a control signal to each servo valve 13, the pressure applied to each control cylinder 7 is gradually changed to the control cylinder target pressure P ₁ '~
The pressure is controlled to be equal to P ₄ ′. As a result, the pressure applied to the object to be compressed can be kept constant at the target actual pressing force _Ps .

Among the above two controls, the height control is given priority and is controlled at high speed using the high speed valve 12, while the pressure control is controlled gradually using the servo valve 13. Therefore, the controls do not interfere with each other, and can be realized in one control loop of controlling the control cylinder 7.

(B-) Implementation using a microcomputer The functions of the first control device 11 described above can also be implemented using a microcomputer. FIG. 3 is a flowchart showing the processing procedure of the first control device 11 at that time. First, in step S31, the height h ₁ to h ₄ of each control cylinder, the pressure P ₁ to _{P 4} applied to each control cylinder, and the pressure P _n of the pressurizing cylinder are measured by the A/D converter 10 from each sensor. Enter via

Next, in step S32, the minimum value _hnio is detected by comparing each of _h1 to _h4 .
After that, in step S33, h ₁ is set to match the height of each control cylinder to this h _nio .
By subtracting the height of ~ _h4 by _hnio , the manipulated variables _δ1 to _δ4 of each control cylinder 7 are obtained. Furthermore, the manipulated variables δ ₁ to _{δ 4} are multiplied by a proportionality constant R _l , converted to a controlled value, and a control signal is sent to each high-speed valve 12 to operate the height of each control cylinder 7 at high speed and match the heights. .

Then, in step S34, the pressure sum P of P ₁ to _{P 4} is added to calculate the target actual pressure _{P s} to be applied to the object 1 to be compressed. A comparison is made as follows.

P′=P _n −P _s (target pressure sum) δP=P−P′ Each control cylinder target pressure P ₁ ′ to _{P 4} ′ is set so that this deviation δP becomes zero. Next, in step S35, the target pressures P ₁ ′ to _{P 4} ′ and P ₁
By finding the difference between ~ _P4 , the manipulated variables _ε1 ~ _ε4 are obtained. Furthermore, these manipulated variables ε ₁ to _{ε 4} are multiplied by a proportionality constant K _p , converted to a controlled variable, and a control signal is sent to each servo valve 13 to gradually reduce the pressure applied to each control cylinder 7. Pressure manipulation is performed to equalize the target pressures P ₁ ′ to _{P 4} ′. Then, in step S36, the steps continue until completion of pressing is confirmed.
By repeating S31 to S35, the actual pressing force applied to the object to be compressed can be kept constant at the target actual pressing force _Ps .

As mentioned above, by realizing height and pressure control in one control loop,
We were able to clarify the control system and reduce external influences. Furthermore, by introducing a computer, it became possible to make subtle adjustments according to the surrounding conditions and the condition of the material to be compressed. In addition, height control does not involve controlling the speed of each control cylinder as in the past, but by directly controlling the height of each control cylinder, improving responsiveness and accuracy.

Further, since no modification is made to the pressurizing cylinder 5, an improvement in accuracy can be expected by attaching this first control device to a conventional press with poor accuracy.

C Second embodiment using second control device (C-) Configuration and operation Figure 4 shows the position sensor 8 and pressure sensors 9 and 2.
The height of each control cylinder 7 obtained from 1,
2 is a block diagram showing in detail the configuration of a second control device 11 for performing the above-described control using the pressure applied to each control cylinder 7 and the pressure of the pressure cylinder 5 as parameters. FIG.

In the figure, the height of each control cylinder 7 is
h ₁ to _{h 4} , the pressure applied to each control cylinder 7
_P1 to _P4 , and the pressure of the pressurizing cylinder 5 is _Pn .

In the height control of the control device 11 using the parameters h ₁ to _{h 4} , first, the height comparison unit 14 arranges h ₁ to _{h 4} in ascending order. Hereinafter, based on the parameters l ₁ to _{l 4} arranged in ascending order, the pressure distribution ratios θ ₁ to θ ₄ of each control cylinder 7 are determined in the pressure distribution ratio determination unit 21, which will be described in detail later.

Further, in the target pressure sum setting section 22, from the pressurizing cylinder pressure P _n and the target actual pressurizing force P _s to be applied to the compressed object 1, the target pressure sum P is determined as P'=P _n - _{P s} (target pressure sum). ′ is set. Note that the target actual pressing force _Ps is set in advance according to the material of the object 1 to be compressed.

The pressure distribution ratio determination unit 21
The pressure distribution _ratios θ _{1 to θ 4} obtained by
Get _U4 . These manipulated variables U ₁ to _{U 4} are multiplied by a proportionality constant R _l in the control law section 16, converted into control variables, and sent control signals to each high-speed valve 12 to increase the height of each control cylinder 7 at high speed. Perform height control to match.

On the other hand, in the pressure control of the second control device 11 using parameters P ₁ to P ₄ , first P ₁
The sum of pressures P of ~ _P4 is determined by the addition unit 17,
In each control _{cylinder target pressure setting section 18, P′=P n −P s ( target} pressure _sum ) Set each control cylinder target pressure P ₁ ′ to _{P 4} ′ so that the deviation δP becomes zero when δP=P−P′. Most simply, the deviation δP may be equally distributed among the four control cylinders 7 to determine P ₁ ′ to P ₄ ′. In addition, in order to avoid interference with height control as much as possible, the pressure distribution ratio determination unit 21
A method of distributing the pressure according to the pressure distribution ratios θ ₁ to _{θ 4} obtained from the equation can also be considered.

Furthermore, a bias amount setting section 2, which will be described in detail later,
3, due to the difference between the pressure cylinder pressure P _n and the pressure sum P, the measured actual pressure P _r (P _r = P _n −
P) is determined, and the bias amount β (the amount for fine-tuning the control) is changed in accordance with the comparison between the measured actual pressing force P _r and the target actual pressing force P _s . This bias amount β is added to each target pressure by the adder 25.
In addition to P ₁ ′ to _{P 4} ′, the difference between the value and P ₁ to _{P 4} is determined by the subtraction unit 19, and the target manipulated variable is calculated.
Get Q ₁ ~ Q ₄ .

These manipulated variables Q ₁ to _{Q 4} are multiplied by a proportionality constant Kp in the control law section 20 and converted into control amounts, and the pressure applied to each control cylinder 7 is gradually controlled by sending a control signal to each servo valve 13. The pressure is controlled to be equal to the cylinder target pressure P ₁ ′ to P ₄ ′. As a result, the actual pressing force applied to the object to be compressed can be kept constant at the target actual pressing force _Ps .

As with the first control device, the above two controls give priority to height control and are controlled at high speed using the high speed valve 12, while pressure control is controlled gradually using the servo valve 13. The following methods are used. Therefore, mutual interference between the controls is relatively rare and can be realized in one control loop of controlling the control cylinder 7.

Also, the bias amount β is set by the bias amount setting section 2.
By calculating and changing the pressure from time to time in step 3, it became possible to match the target pressures P ₁ ′ to P ₄ ′ with high accuracy.

(C-) Pressure distribution ratio determination method by pressure distribution ratio determination unit The pressure distribution ratios θ ₁ to _{θ 4} are determined in the pressure distribution ratio determination unit 22 as follows. First, in this case, as initial values, the pressure distribution ratios θ ₁ to _{θ 4} are each 1/
Set it to 4. Here, each correction parameter μ ₁ to _{μ 4} is determined based on the deviation of the heights h ₁ to _{h 4} as will be described in detail later. Therefore, θ _i = θ _i + μ _i (i=1...4) ...(1) By executing equation (1), the pressure distribution ratio θ ₁
~θ ₄ is found.

FIG. 5 is a flowchart showing an example of the flow of determining correction parameters. Here, as described above, l ₁ to _{l 4} are obtained by sorting h ₁ to _{h 4} in order of height. Also, x is a predetermined basic correction value, y is a deviation reference value,
This is a parameter that considers that if the difference in height is greater than the deviation reference value y, there is a difference in the heights of the two (there is a size relationship).

As shown in the figure, the cases can be divided into 17 cases, C1 to C17, depending on the heights l ₁ to _{l 4} . Below, we will give examples of the correction parameters μ ₁ to _{μ 4.}
Explain the decision flow.

Example 1 When l ₁ = l ₂ > l ₃ > l ₄ , YES in step S1, NO in the next step S2, and furthermore, in step S5, the difference between l ₂ and l ₃ is larger than the deviation reference value y, so
YES, similarly YES at step S6,
Therefore, the correction parameters α ₁ to _{α 4} for case C3 are determined. Here, h ₁ = l ₂ , h ₂ = l ₃ , h ₃ = l ₄ ,
If h ₄ = l ₁ , μ ₁ = α ₂ = −x, μ ₂ = α ₃
= (1/2)x, μ ₃ = α ₄ = (3/2) x, μ ₄ = α ₁ = −
x, and according to equation (1), θ ₁ = θ ₁ −x θ ₂ = θ ₂ + (1/2) x θ ₃ = θ ₃ + (3/2) x θ ₄ = θ ₄ − x and the pressure It determines the distribution rate. In this way, the relatively high control cylinder 7 (height h ₁ ,
The height is adjusted by lowering the pressure distribution ratio of the lower control cylinder 7 ( _height h ₂ , h ₃ ) and increasing the pressure distribution ratio of the lower control cylinder 7 (height h 2 , h 3 ).

Example 2 When l ₁ > l ₂ ≒ l ₃ , l ₃ ≒ l ₄ , l ₂ > l ₄ NO at step S1, no at step S8
YES, in the next step S9, l ₂ and l ₃ are
There is almost no difference (the difference between the two is smaller than y), so NO. In step S11, there is also almost no difference between l ₃ and l ₄ , so NO. However,
In the next step S12, the difference between l ₂ and l ₄ is
Since this cannot be ignored (the difference between the two is greater than y), the answer is YES and case C10 is determined.
The following procedure is similar to Example 1 described above.

As shown in Examples 1 and 2, the correction parameters μ ₁ to _{μ 4} are determined based on various deviations of the heights l ₁ to l ₄ .

(C-) How to set the bias amount using the bias amount setting section (C--1) Necessity of setting the bias amount during press processing For control in a large span where the target actual pressurizing force P _s is 10 to 1500 (tw/m ² ) It is known from experience that in order to servo control a cylinder, accuracy is improved by adding an appropriate bias amount according to the target actual pressurizing force _Ps to the operation amount for the servo command. However, even if an appropriate bias amount is set in advance at the start-up of the machine, pressure accuracy may not be obtained as expected during press processing due to ambient conditions (oil temperature, ambient temperature, etc.). Therefore, it is necessary to reset the bias amount β even during press working.

(C--2) Bias amount setting method In the bias amount setting section 23, the bias amount β is set as follows. First, by comparing the measured actual pressing force P _r and the target actual pressing force P _s , if P _r < P _s , it is assumed that the bias amount β set in advance according to the target actual pressing force P _s is large, and the bias is adjusted. By using the value γ (>0) and setting β=β−γ, the bias amount β is reset to a lower value. On the other hand, if P _r >P _s , it is assumed that the preset bias amount β is small, and the bias amount β is reset to a higher value by setting β=β+γ. Further, if P _r =P _s , the bias amount β is determined to be accurate and is not changed.

(C‐‐3) Effect of bias amount setting As shown above, at any time during press processing,
By changing the bias amount β while comparing the measured actual pressurization P _r with the target actual pressurization P _s , it has become possible to control the error to within 5.5% under any usage conditions.

(C-) Implementation using a microcomputer The functions of the second control device 11 described above can also be implemented using a microcomputer. Figure 6 shows the control device 11 at that time.
This is a flowchart showing the processing procedure. First, in step S41, the height h ₁ to h ₄ of each control cylinder, the pressure P ₁ to _{P 4} applied to each control cylinder, and the pressure P _n of the pressurizing cylinder are measured by the A/D converter 10 from each sensor. Enter via

Next, in step S42, h ₁ to _{h 4} are compared and sorted into l ₁ to _{l 4} in ascending order. After that, based on the parameters l ₁ to l ₄ arranged in descending order in step S43,
The pressure distribution ratio θ ₁ to _{θ 4} of each control cylinder 7 is determined by the pressure distribution ratio determination method described in (C-).
Determine. Next, in step S44, P' = P _n - P _s (target pressure sum) is calculated from the pressurizing cylinder pressure P _n and the target actual pressure P _s to be applied to the compressed object 1, and this target pressure sum P' is The manipulated variables δ _{1 to δ 4 are obtained by integrating the pressure distribution ratios θ 1 to θ 4} obtained in step S43 and further calculating the difference between the integrated values and P ₁ to P ₄ . Furthermore, this manipulated variable δ ₁ ~
By multiplying δ ₄ by a proportional constant R _l , converting it into a control amount, and sending a control signal to each high-speed valve 12, the height of each control cylinder 7 is operated at high speed and the heights are made to match.

Then, in step S45, the pressure sum P of P ₁ to _{P 4} is added to obtain the pressure sum P, the pressurizing cylinder pressurizing force P _n , and the preset target pressure P _s to be applied to the compressed object 1 as shown below. Make a comparison like this.

P′=P _n −P _s (target pressure sum) δP=P−P′ so that this deviation δP becomes zero,
Set each control cylinder target pressure P ₁ ′ to P ₄ ′.

Furthermore, in step S46, the measured actual pressing force P _r (P _r = P _n - P) is obtained from the difference between the pressurizing cylinder pressing force P _n and the pressure sum P, and the difference between the measured actual pressing force _Pr and the target actual pressing force P _s is calculated. Based on the comparison,
The bias amount β is determined by the bias amount determination method described in (C-). And the steps
In S47, this bias amount β is set to each target pressure.
In addition to P ₁ ′ to _{P 4} ′, the difference between that value and P ₁ to P ₄ is defined as target manipulated variables Q ₁ to _{Q 4} . Furthermore, these target manipulated variables Q ₁ to _{Q 4} are multiplied by a proportionality constant K _p , converted to a control amount, and a control signal is sent to each servo valve 13 to gradually control the pressure applied to each control cylinder 7. Pressure manipulation is performed to equalize the cylinder target pressures P ₁ ′ to P ₄ ′. Then, in step S48, the steps continue until completion of pressing is confirmed.
By repeating S41 to S47, the balance of the slide 4 can be maintained and the actual pressure P _r applied to the object to be compressed can be kept constant at the target actual pressing force P _s .

As described above, similar to the first control device, by realizing height and pressure control in one control loop, it was possible to clarify the control system and reduce external influences. Furthermore, by introducing a computer, it became possible to make subtle adjustments according to the surrounding conditions and the condition of the material to be compressed. In addition, height control does not control the speed of each control cylinder as in the past.
By directly controlling the height of each control cylinder, responsiveness and accuracy can be improved.

Further, since no modification is made to the pressurizing cylinder 5, it is possible to expect an improvement in accuracy by attaching this control device to a conventional press with poor accuracy.

Furthermore, since control is performed in consideration of the pressure distribution ratio and the amount of bias, it is possible to perform height and pressure control with higher accuracy than in the first control device described in B.

D. Third embodiment using only height control Even if only the height control of the second embodiment using the second control device described in C is used, considerable effects can be expected to be obtained. FIG. 7 is a schematic explanatory diagram of a press control device according to a third embodiment. In the figure, the servo amplifier 26 corresponds to the subtraction section 15 and the control section 16 in FIG. 4, the servo valve 27 corresponds to the high-speed valve 12 in FIG. 1, and the other configurations and operations are A, Since it has already been described in C, the explanation will be omitted.

In this embodiment, since only height control is performed, the high-speed valve 12 is operated in order to avoid interference with pressure control.
There is no need to use an ON-OFF digital method. Therefore, the servo valve 27 can perform analog continuous control with high precision. Moreover, since the actual pressurizing force is taken into consideration by changing the pressure distribution ratios θ ₁ to _{θ 4} of each control cylinder 7, pressure control is also taken into consideration.

In addition, compared to the first and second embodiments, since the control target can be narrowed down to one (height), there is no need to consider interference between height control and pressure control, and the device configuration can be simplified ( In particular, there are advantages such as being able to control the control device 11).

E Supplement: In the first to third embodiments above, proportional control was used as the control law, but depending on the characteristics of the compressed object or the hydraulic system, differential control, integral control, feedforward control, etc. may also be performed. It is possible to do so. Further, in the first and second embodiments, the height control valve 12 and the pressure control valve 13 are
It is also possible to simplify the device by using both in one valve.

Further, in the third embodiment, a servo valve is used, but it goes without saying that high-speed control can be realized by using a high-speed valve instead.

(Effect of the invention) As explained above, according to this invention, 1
By controlling the height and pressure of each control cylinder with two control loops, the slide is kept in balance under any circumstances or conditions of the compressed object, and the pressure applied to the compressed object is always kept constant. be able to.

[Brief explanation of drawings]

FIGS. 1a and 1b are explanatory diagrams of the three-dimensional configuration of a press device showing the first and second embodiments of the present invention, respectively;
2 is a block diagram showing in detail the configuration of the first control device in FIG. 1, and FIG. 3 is a flowchart showing the processing procedure when a microcomputer is used as the first control device. , FIG. 4 is a block diagram showing in detail the configuration of the second control device in FIG. 1, FIG. FIG. 6 is a flowchart showing the processing procedure when a microcomputer is used as the second control device, FIG. 7 is a schematic explanatory diagram of the press control device showing a third embodiment of only height control, and FIG. The figure shows a state of a compressed object in which the slide (upper mold) is difficult to balance. DESCRIPTION OF SYMBOLS 1... Compressed object, 4... Slide, 5... Pressure cylinder, 6... Bed, 7... Control cylinder, 8... Position sensor, 9... Pressure sensor, 11
...Control device, 12...High speed valve, 13...Servo valve, 21...Pressure distribution ratio determining section, 23...
...Bias amount setting section.

Claims (1)

[Claims] 1. A device for controlling the balance of a slide pressed by a pressure cylinder of a press device and the actual pressure applied to an object to be compressed, comprising a plurality of slides arranged on a bed and supporting the slide. a control cylinder; a first pressure sensor installed in the pressure cylinder to detect the pressure of the pressure cylinder; and a position sensor installed in each control cylinder to detect the height of the control cylinder. , a second pressure sensor that is installed in each of the control cylinders and detects the pressure applied to the control cylinders; and a first comparison means that compares the heights of each of the control cylinders obtained by the position sensors. , Based on the comparison result by the first comparison means,
a first operation amount determining means for determining a first operation amount of each of the control cylinders so that the heights of each of the control cylinders are the same; a first control means for controlling a cylinder; and a sum of the pressurizing force of the pressurizing cylinder obtained from the first pressure sensor and the pressure applied to each of the control cylinders obtained from the second pressure sensor. an actual pressing force measuring means for measuring the actual pressing force based on a difference; a second comparing means for comparing the actual pressing force obtained by the actual pressing force measuring means with a preset target actual pressing force; and a comparison by the second comparing means. Based on the results,
a second operation amount determining means for determining a second operation amount of each of the control cylinders so that the pressure of each of the control cylinders reaches the target actual pressure; and a second control means for controlling the control cylinder. 2. A device for controlling the balance of the slide pressed by the pressure cylinder of the press device and the actual pressure applied to the object to be compressed, comprising a plurality of control cylinders disposed on the bed and supporting the slide; a first pressure sensor that is installed on a pressure cylinder and detects the pressing force of the pressure cylinder; a position sensor that is installed on each of the control cylinders and detects the height of the control cylinder; and a position sensor that is installed on each of the control cylinders and detects the height of the control cylinder a second pressure sensor for detecting the pressure applied to the control cylinder; a first comparison means for comparing the height of each control cylinder obtained by the position sensor; and a first comparison means for comparing the heights of the control cylinders obtained by the position sensor; The target pressure sum of each of the control cylinders is determined from the difference between the pressurizing force of the pressurizing cylinders obtained by the sensor and the preset target actual pressurizing force, and the relative The pressure distribution ratio of each of the control cylinders is determined so that the control cylinder located at a high position is set to a low value, and the control cylinder located at a low position is set to a high value, and the pressure distribution ratio is set to the target pressure sum. a first operation amount determining means that determines a first operation amount of each of the control cylinders by integrating; and a first control that controls each of the control cylinders to operate only the first operation amount. means, and an actual applying force for measuring the actual pressing force based on the difference between the pressing force of the pressurizing cylinder obtained from the first pressure sensor and the sum of pressures applied to each of the control cylinders obtained from the second pressure sensor. pressure measuring means; second comparison means for comparing the actual pressing force obtained by the actual pressing force measuring means and the target actual pressing force; and the pressurizing force of the pressurizing cylinder obtained by the first pressure sensor and the After determining the target pressure sum of each of the control cylinders from the difference between the target actual pressurizing forces, the pressure difference between this target pressure sum and the pressure sum applied to each of the control cylinders is determined, and this pressure difference and the pressure sum of each of the control cylinders are calculated. By adding a bias amount that increases if the actual pressing force is larger than the target actual pressing force and decreases if it is smaller than the target actual pressing force based on the second comparison result to the amount based on the individual pressure values, the second A press control device comprising: a second operation amount determining means for determining an operation amount; and a second control means for controlling each of the control cylinders so as to operate the control cylinders by the second operation amount. 3 A device for controlling the balance of a slide pressed by a pressure cylinder of a press device, comprising a plurality of control cylinders disposed on the bed to support the slide, and a plurality of control cylinders provided on the pressure cylinder to control the pressure. a pressure sensor that detects the pressure applied to the pressure cylinder; a position sensor installed in each of the control cylinders that detects the height of the control cylinder; and a position sensor that detects the height of each of the control cylinders as determined by the position sensor. a comparison means for comparing; a target pressure sum determining means for determining a target pressure sum of each of the control cylinders from a difference between the pressurizing force of the pressurizing cylinder obtained by the pressure sensor and a preset target actual pressurizing force; Based on the comparison result by the comparison means, the pressure distribution ratio of each control cylinder is determined so that the control cylinder located at a relatively high position is set to a low value, and the control cylinder located at a relatively low position is set to a high value; a manipulated variable determining means that determines the manipulated variable of each of the control cylinders by integrating this pressure distribution ratio to the target pressure sum of each of the control cylinders determined by the target pressure sum determining means; and a control means for controlling each of the control cylinders as desired.