JPH0133252B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for controlling the position of a gripper in an automatic plate-shaped object bending device, and more specifically, to a method for controlling the position of a gripper in an automatic plate-shaped object bending device, and more specifically, to a method for controlling the position of a gripper in a plate-shaped object automatic bending device. The present invention relates to a method for controlling the position of a gripper so as to

[Prior Art] Previously, press brake type bending machines and the like have been used to bend plate-shaped bodies such as iron plates, but all of these machines were controlled manually. Therefore, work efficiency is very low.
It also required many workers.

Therefore, the present applicant has previously proposed an automatic folding device that is equipped with a robot that cooperates with a press brake type folding machine and can thereby automatically bend a plate-shaped body. Such a proposed automatic folding device is disclosed in, for example, Japanese Patent Application Laid-Open No. 54-1993, published on October 9, 1979.
No. 130463, JP-A-55-48425, published on April 7, 1980,
This is disclosed in Japanese Patent Application Laid-open No. 55-54215, published on April 21, and Japanese Patent Application Laid-Open No. 139121, published on October 30, 1980.
In particular, Japanese Patent Laid-Open No. 55-139121 discloses specific control of robots.

In all of these conventional automatic folding devices, when positioning a workpiece or a plate-like body with respect to a folding machine, the plate-like body is gripped and positioned by a gripper. However, as the upper mold is lowered, the ends of the plate-shaped body spring up from the horizontal position, so that it is impossible to perform the bending operation while holding the plate-shaped body with the grippers.

Therefore, conventionally, the plate-shaped body is positioned and gripped with grippers until the upper mold comes into contact with the plate-shaped body, and then the grippers are released and the upper mold is further lowered to bend the plate-shaped body. Then, after bending, grip the plate-shaped body at an appropriate position again with grippers,
Raise the upper mold. The gripper then positions it for further bending or releases it once the bending is complete.

[Problems to be Solved by the Invention] In the conventional method as described above, it was necessary to release the gripper from gripping the plate-shaped body or to change the grip to another position. However, depending on the type of plate-shaped object, plastic deformation or bending may occur during the bending process, and as a result, the position where the gripper grips the object again becomes unclear and deviates from the initially gripped position. . This will result in a product with an incorrectly bent shape, so it is preferable not to release or change grippers midway through the process.

This invention was made to solve the above-mentioned problems, and an object of the present invention is to enable bending work to be performed while holding a plate-shaped body with a gripper.

[Means for Solving the Problems] A gripper position control method in an automatic plate-shaped object folding device according to the present invention detects the height (h) of an upper die relative to a lower die when bending a plate-shaped body. Then, from this detected height, calculate the springing angle (θ) of the plate-shaped object during the bending operation, calculate the following position of the gripper from the calculated springing angle, and then calculate the following position of the gripper based on this calculated following position. The position of the gripper displacement mechanism is controlled, thereby causing the position of the gripper to follow the upward movement of the plate-shaped body.

[Function] In the present invention, the following position of the gripper with respect to the bounce of the plate-like object is calculated every moment during the bending operation of the plate-like object, and the position of the gripper displacement mechanism is controlled based on the calculated follow-up position. This allows the position of the gripper to follow the springing up of the plate-like object, thereby making it possible to perform the bending operation while gripping the plate-like object with the gripper.

[Embodiment] FIG. 1 is a partially cutaway side view showing the mechanical configuration of a press brake type folding machine used in an embodiment of the present invention. Figure 2 shows the line in Figure 1 -
FIG. Here, with reference to FIGS. 1 and 2, the configuration of a press brake type folding machine used in an embodiment of the present invention will be described. The press brake type folding machine 1 has columns 3a and 3b at both ends in the width direction, and a bed 5 connects these columns 3a and 3b. On this bed 5, a lower mold 7a is placed.
However, it is installed with the mold groove facing upward. An upper mold 7 having a cutting edge facing the mold groove of this lower mold 7a
b is attached to the ram 9. This ram 9
The lifting and lowering thereof is controlled by a control device (not shown). Note that a plurality of lower molds 7a and upper molds 7b are installed, each having a different mold groove or cutting edge shape, and are configured so that any lower mold and upper mold can be selected as needed. It's okay.

An engagement convex portion 5a extending in the width direction of the bed 5 is formed on the front end surface (left side surface in FIG. 1) of the pre-brake type folding machine 1. An engagement recess formed in the robot sliding table 11 engages with the engagement protrusion 5a. Therefore, the robot slide table 11 is
It is movable relative to the folding machine 1 in its width direction (in the direction of arrow 13 in FIG. 2). That is, a rack 6 extending in the width direction of the bending machine 1 is formed on the front end surface of the bed 5, and a pinion 8 that meshes with the rack 6 is provided on the robot sliding table 11, and this pinion 8 is connected to a hydraulic motor 10. ing. Therefore, by rotationally driving the hydraulic motor 10, the pinion 8 can be rotated, and the robot slide table 11 can be slid along the bed 5 in the direction of the arrow 13. A guide 15 is horizontally supported at the upper end of the robot sliding table 11, and this guide 15 extends beyond the bed 5 of the folding machine 1 to the rear of the folding machine 1. Guide 15 includes:
An arm holder or sliding body 17 is supported so as to be slidable in the front-rear direction of the folding machine 1, that is, in the direction of arrow 19 in FIG. The sliding body 17 has a shaft 2
1 supports one end of the arm 23. Therefore, this arm 23 is rotatable about the shaft 21 in the direction indicated by the arrow 25 in FIG. A gripper 27 is provided at the other end of the arm 23.
This gripper 27 is rotated by a hydraulic motor 29. The sliding movement of the sliding body or arm holder 17 is controlled by a hydraulic motor 31, and the rotation of the arm 23 is controlled by a hydraulic motor 33.

The gripper will now be described in detail with reference to FIGS. 3 and 4. The fixed claws 27a and the movable claws 27b constituting the gripper 27 are housed in a box 37 fixed to the shaft 35 of the hydraulic motor 29. The box 37 is provided with an opening 37a, and the two claws 27 are inserted through the opening 37a.
The tips of a and 27b project outward. A guide 39 is provided within the box 37, and a slider 41 is supported on the guide 39 so as to be slidable in its length direction. The slider 41 is an actuator 43 whose one end is fixed to the front inner wall of the box 37.
A fixed claw 27a is connected to the slider 41.
is fixed. A shaft 45 that rotatably supports the movable claw 27b is attached to the upper end surface of the fixed claw 27a. One end of the actuator 47 is connected to the lower end of the fixed claw 27a, and the other end of the actuator 47 is connected to the rear end of the movable claw 27b. By operating the actuator 43, the fixed claws 27a and 27b, that is, the gripper 27 can be moved in and out of the opening 37a of the box 37 in the direction of the arrow 49.
Further, by operating the actuator 47, the movable claw 27b can be rotated in the direction of the arrow 51, and therefore the opening angle with respect to the fixed claw 27 can be controlled.

Returning to FIGS. 1 and 2 again, in front of the press brake type folding machine 1 is a carry-in conveyor 5.
3 and a standby conveyor 55 are provided. The carry-in conveyor 53 carries the plate-shaped object to the standby conveyor 55. The standby conveyor 55 is supported by a pantograph 57, which is bent and extended by an actuator 59. A stopper 61 is provided at one end of the standby conveyor 55 for abutting and positioning the plate-shaped body there. Supporters 63 are provided on both sides of the upper end of the standby conveyor 55 to support the portion of the plate-shaped body held on the conveyor 55 that protrudes from the top of the conveyor 55. This supporter 63 is normally located at the position shown by the solid line in FIGS. 1 and 5, but if necessary, it can be opened by the actuator 65 to the position shown by the two-dot chain line in FIGS. 2 and 5. It will be done.

In the example shown in FIGS. 1 and 2, a delivery conveyor 67 and a delivery conveyor 69 are further provided behind the press brake type folding machine 1.
Like the standby conveyor 55, the delivery conveyor 67 is supported by a pantograph 73 that is bent and extended by an actuator 71.

Here, an outline of a series of folding operations performed by this automatic folding device will be explained with reference to FIGS. 6 to 10. First, the plate-like object or workpiece 100 is transported by the carrying-in conveyor 53.
is carried onto the standby conveyor 55, and further, by conveying the workpiece 100 by the conveyor 55,
The workpiece 100 is brought into contact with the stopper 61. Therefore, the war piece or plate-shaped body 100 is positioned and held on the standby conveyor 55. Activating the actuator 59 (Fig. 1),
Extend the pantograph 57. In response, the standby conveyor 55 rises as shown by the two-dot chain line in FIG. Then, the hydraulic motor 33 (FIG. 2) is activated, and the gripper provided at the tip of the arm 23 moves upward to the workpiece 100 on the standby conveyor 55, as shown by the two-dot chain line in FIG.
Rotate it so that you can grasp it. The hydraulic motor 31 is controlled as necessary to move the arm holder or sliding body 17 on the guide 15 and control the position of the gripper 27 with respect to the workpiece or plate-shaped body 100. This state is shown in FIG. Thereafter, the actuator 43 (FIG. 3) is actuated and the actuator 47 is actuated to cause the gripper 27 to grip the workpiece 100 at a predetermined position (FIG. 8).

In this state, as shown in FIG. 9, the workpiece 100 is folded into the lower die 7a and the upper die 7
Position with respect to b. That is, the hydraulic motor 33 (FIG. 2) is operated and the arm 23 is positioned so that the workpiece 100 is placed on the lower mold 7a and is horizontal. At the same time, the hydraulic motor 31 is controlled to move the arm holder 17. At this time, the rotation of the gripper 27 may be controlled by operating the hydraulic motor 29 (FIG. 3), if necessary. In this way, the workpiece 100 is formed into the lower die 7a and the upper die 7.
b.

Thereafter, the ram 9 of the bending machine 1 is lowered, and the workpiece 100 is folded by the upper die 7b and the lower die 7a as shown in FIG. At this time, the workpiece 100 springs up in the direction shown by the arrow 75 in FIG. 10 in response to the lowering of the upper die 7b.
A feature of the present invention is that the gripper 27 follows the upward movement of the plate-shaped body 100 during the bending operation, thereby allowing the gripper 27 to perform the bending operation while gripping the workpiece 100. . A series of bending operations as described above are all controlled by a microprocessor or microcomputer.

FIG. 11 is a schematic block diagram showing an example of an electric circuit in an automatic plate-shaped object folding device used in the present invention. CPU81 passes through bus 83
It is connected to RAM85 and ROM87. RAM
85 stores data necessary for calculation or control in the CPU 81, and ROM
87 is used to program calculations or control procedures for the CPU 81, and also stores necessary fixed information such as information regarding the bending machine 1 and the workpiece. A console 89 is connected to the bus 83. This console 89 is used for the press brake type folding machine 1 and the conveyors 55 and 6.
7 etc. or to perform teaching operations for automatic bending.
Includes a keyboard 91. This keyboard 91 includes alphanumeric keys and various function keys. Information or data input through the keyboard 91 is stored in the RAM 85 through the bus 83 and is also provided to the CPU 81.
The console 89 includes a display 93, on which data input from the keyboard 91 and other necessary information from the CPU 81 are displayed as necessary. Note that a cassette deck 95 may be housed in the console 89 so that, for example, magnetic tape can be used as an external memory. A series of information for various bending operations is stored on the magnetic tape, and the necessary data is read from it by the cassette deck 95, or the necessary data is transferred to the magnetic tape by the cassette deck 95.
Write by.

The bus 83 connected to the CPU 81 further includes:
A press brake type bending machine 1 is connected, and the elevation of its upper die 7a, that is, the ram 9, is controlled. This folding machine 1 is provided with an encoder 1a for outputting information (height data h described later) according to the elevation of the ram 9, and the information from the encoder 1a is transmitted to the CPU 81 and RAM 8 through a bus 83.
given to 5. The bus 83 further includes a hydraulic motor 10 and actuators 43, 47, 5.
9, 65 and 71 are respectively connected through appropriate interfaces. Therefore, these devices 10, 43, 47, 59, 65 and 71
is also controlled by the CPU 81.

Respective positioning devices 97, 99 including hydraulic motors 29, 31 and 33 included in the robot
and 101 are also coupled to bus 83. The positioning devices 97, 99 and 101 are each
The angles β, α and position xj, which will be described later, are controlled.

Here, information to be taught using the console 89 will be explained using FIG. 12 as an example. In the example shown in FIG. 12, , , and are respectively folded. Therefore, the coordinate position information of each of these points is taught using the XY coordinate system. At the same time, the positional information of the points at both ends of the workpiece 100 is also taught because of the necessity for positioning. If there are multiple bending points, the bending order must be taught at the same time. In the example of FIG. 12, the folding order would be the folding points, , and so on.
From the console 89, further workpiece 1
Workpiece 10 such as plate thickness t, plate width, and plate material (for example, iron, aluminum, etc.)
Information or data related to 0 is also input. The plate thickness t is especially necessary for control in the embodiments described later. Furthermore, if mold replacement is required, first input the type of mold needed and the order in which it will be used. Then, during the bending operation, an appropriate mold is automatically selected.

FIG. 13 is a diagram showing a model of the folding process that forms the theoretical basis of this invention. The tip of the upper mold 7b is formed as a circular arc having a radius (ru). The lower mold 7a has a side portion forming a mold groove, and the top portion of the side portion that contacts the workpiece 100 is formed into an arc shape having a radius (rd). Let the distance from the center of curvature of this top part to the center of the mold groove be (w). The thickness of the workpiece 100 existing between the lower mold 7a and the upper mold 7b is t, and the workpiece 10
0 is bent into an arc shape having a predetermined radius of curvature (R) as the upper die 7b descends. The distance or height between the center of curvature at the tip of the upper mold 7b and the center of curvature at the top of the lower mold 7a is defined as (h). Information regarding this height (h) is obtained from the encoder 1a shown in FIG. As the upper mold 7b is lowered, that is, as the height (h) becomes smaller, the workpiece 100 jumps up from the horizontal state, and the angle at which it jumps up is defined as (θ).

Assuming a model like this, the following equation (1) is obtained, and by transforming equation (1), equation (2) is obtained.

(R+h-ru) ² +w ² = (R+t+rd) ² ...(1) R ² +2R(h-ru)+(h-ru) ² +w ² =R ² +2R(t+rd)+(t+rd) ² ∴R= 1/2・(h-ru) ² −(t+rd) ² +w ² /t
+ru+rd−u...(2) On the other hand, from equations (3), (4), and (2), as shown in equation (5), the jump angle (θ) of the workpiece 100 is determined by the height of the upper die 7b. It is expressed as a function of h.

(R + t + rd) sin θ = w ... (3) (R + t + rd) cos θ = (R + h - ru) ... (4) θ = tan ^-1 {w / (R + h - ru)} = tan ^-1 w /
{1/2・(h−ru) ² −(t+rd) ² +w ² /t+ru+rd
−h}+h−ur……(5) In a preferred embodiment of the present invention, focusing on the correlation between the bounce angle (θ) and the height (h) of the upper mold, the bounce angle (θ) is This is used to control the gripper 27 to follow it. For this purpose, the above formula (5) and the necessary data (ru, t, rd
etc.) are stored as a table in the ROM 85 (FIG. 11), for example.

Here, with reference to FIG. 14, position data (xi, yi) for follow-up control of the gripper 27 is determined. In FIG. 14, the distance between the center of curvature of the top of the lower die 7a and the center of rotation of the gripper 27 is defined as (l). As shown in FIG. 14, when the workpiece 100 is bent by an upward angle (θ), point A moves to A'. From this Figure 14,
The position (xi, yi) of the rotation center of the gripper 27 is (6)
It is given by Eq.

xi={w−(rd+t/2)sinθ}+lcosθ yi={−rd+(rd+t/2)cosθ}+lsinθ……(6) By substituting equation (5) into equation (6), this position (xi ,
yi) is the height (h) of the upper mold 7b (first
It is clear that it can be expressed as a function of Figure 2).

In this invention, the position of the center of rotation of the gripper 27 is sequentially calculated according to the change in the height of the upper mold 7b, and the necessary angle and position of the control axis are calculated based on the calculated position information. , hydraulic motors such as 29, 31 and 33, thereby allowing the gripper to perform the bending operation while holding the workpiece.

FIG. 15 is a model showing how the position (xi, yi) of the center of rotation of the gripper of the press brake type folding machine shown in FIGS. 1 and 2 is expressed. In FIG. 15, the length of the arm, that is, the center of rotation of the arm 23 (FIG. 1), that is, the distance from the shaft 21 to the center of rotation of the gripper 27 is (L). Then, in order to move the center of the gripper 27 to the position (xi, yi), the arm holder 17
It is necessary to move the arm holder or sliding body 17 along the guide 15 (FIG. 1), and the position of this arm holder or sliding body 17 is assumed to be (xj). The distance between the rotation center of the arm 23 in the Y-axis direction and the origin is (yo).

From FIG. 15, it can be seen that the following equation (7) holds true, and therefore the position (xj) of the arm holder 17 in the X-axis direction is expressed by equation (8).

(xj−xi) ² + (yi−yo) ² = L ² …(7) (xi=±√ ² −(−) ² +xi …(8) From the above equation (8), the Although there are two positions (xj) in the axial direction, one of them is selected here depending on the direction of inclination of the arm 23 with respect to the Y-axis direction.

In addition, in order to sequentially control the rotation center of the gripper 27 to a predetermined position (xi, yi), it is necessary to not only control the position (xj) of the arm holder 17, but also to control the position (xj) of the arm holder 17.
The angle of arm 23 (α) and the angle of gripper 27 relative to the arm (θ) must be controlled.

From Figure 15, these angles (α) and (β)
can be obtained from the following equations (9) and (10).

tanα＝(yi−yo)／(xj−xi) ∴α＝tan ⁻¹ (yi−yo)／(xj−xi) ……(9) θ＝tan ⁻¹ yi／xi ∴β＝θ−α ＝ (tan ^-1 yi/xi) - α ...(10) From equations (8), (9) and (10) above, the position (xi, yi) of the center of rotation of the gripper 27 follows the bounce of the workpiece. It can be seen that in order to control the position by controlling the position (xj) of the arm holder 17, the angle (α) of the arm 23, and the angle (β) of the gripper body with respect to the arm. These (xj), (α) and (β) are shown in Figures 1 and 2.
The press brake type folding machine shown in the figure is controlled by hydraulic motors 31, 33 and 29, respectively.

Figures 16A and 16B represent Figures 1 and 2.
12 is a flowchart for explaining the operation of the automatic plate-shaped object folding device shown in FIGS.
Hereinafter, with reference to FIGS. 16A and 16B, the operation of the automatic plate-shaped object bending device and the gripper position control method according to an embodiment of the present invention will be described. In the first step S101, the CPU 81 (FIG. 11) uses the robot to position the workpiece relative to the bending machine (press brake). The state is shown in FIG. Specifically, the CPU 81 controls the hydraulic motors 10, 29, 31, and 33,
Based on the taught bending point information, the workpiece is positioned between the lower die 7a and the upper die 7b. Subsequently, in step S103, the CPU 81 sets flags and counter contents k provided in appropriate areas of the RAM 85. The flag is set according to the symbol (10) or (-) in equation (8). For example, step
When the arm 23 is positioned in S101, this flag is set to "1" or "0" depending on whether the arm 23 is clockwise or counterclockwise with respect to the vertical direction (the position shown in FIG. 1). Also,
The counter k represents the sequential points at which the upper die 7b is to be positioned, and the upper die 7b is sequentially positioned at each positioning point and finally lowered to a position corresponding to the required bending angle, etc. Ru. Initially, set k=1.

In the following step S105, the CPU 81 controls the bus 8 so as to lower the upper mold 7b to the position Yk corresponding to the value of k set by the counter.
A command is given to the press brake type folding machine 1 through 3. In response, the press brake 1 lowers the ram 9 (FIG. 1), thus lowering the upper die 7b.
descends. At this time, in step S107,
Information corresponding to the height (h) of the upper die 7b (FIG. 13) is taken in from the encoder 1a (FIG. 11).
Then, based on this height (h), it is determined whether the range is applicable to the model explained in FIG. 14. Specifically, this is determined based on whether h≦ru+t+rd. The fact that (h) is larger than (ru+t+rd) means that the upper die 7b has not yet come into contact with the workpiece 100, and the above model cannot be applied, so the step continues.
Jump to S127. If (h) is within the applicable range, in the next step S111, the CPU 8
1 is the gripper 2 to be followed by the equation (6) above.
7. Calculate the position (xi, yi) of the center of rotation. At this time, the jump angle (θ) is used, but the information (ru) necessary for equation (5) to calculate this (θ),
(rd), (t) and (w) are each pre-programmed into ROM 87 by console 89. Further, (h) is obtained from the encoder 1a, and (l) is already known when positioning the workpiece in step S101. In the following step S113, the CPU 81 checks whether the flag is set to "1". This is to select the symbol (+) or (-) in equation (8).

If the flag is set to ``1'', in the following steps S15 and S117, the symbol (+)
and calculate (xj) and (α) using equations (8) and (9), respectively. Flag is "0"
If set to , steps S119 and
In S121, the symbol (-) is selected and (xj) and (α) are calculated using equations (8) and (9), respectively. Regardless of whether the flag is "1" or "0", after calculating (xj) and (α), in the following step S123, (β) is calculated using equation (10). And the next step
In S125, the position of arm holder 17 is (xj)
A command is given to the drive circuit of the positioning device 99 to move the arm 23 to an angle (α), a command is given to the drive circuit of the positioning device 101 to rotate the arm 23 to an angle (α), and the angle of the gripper body is changed to (β). A command is given to the drive circuit of the positioning device 97 to rotate it. In this way, by causing the gripper 27 to follow the point at which the workpiece 100 is gripped as the upper die 7b descends, the workpiece can be bent while the gripper 27 grips the workpiece. I can do it.

After that, the CPU 81, in step S127,
It is determined whether the upper die 7b has reached the target position Yk. This can be determined by looking at information from a servo system (not shown) included in the folding machine 1. If the Yk position has not been reached, the process returns to step S107. In the next step S129, the CPU
At step 81, it is determined whether the upper die 7b has reached the final target position Y or not. This can be determined by checking whether the content k of the counter provided in the RAM 85 is the number required for one bending operation.

If the upper mold 7b has not yet reached the final target position Y, in step S131, the CPU 81
Increment counter k in RAM85. Then, the process returns to step S105.

If the upper mold 7b has reached the final target position Y, in the following step S133, the CPU 81
A command is given to the servo system of the press brake 1 to stop the lowering of the ram 9, that is, the upper die 7b. When detecting that the upper die 7b has stopped in step S135, the CPU 81 executes the following steps S137, S139,
S141 and S143 are executed to return the upper mold 7b to its initial position, that is, the home position. In this way, follow-up control of the center of rotation of the gripper 27 in the press brake type folding machine shown in FIGS. 1 and 2 is achieved.

Next, other embodiments of the invention will be described.

FIG. 17 is a partially cutaway side view of a main part of a press brake type folding machine used in another embodiment of the present invention, and particularly corresponds to FIG. 1. This press brake type bending machine has a guide 15 that supports another vertical guide 16 movably in the direction of arrow 103, and the vertical guide 16 has a moving body 28 provided with a gripper 27 in the direction of arrow 103.
It is supported in the direction of movement. In addition, mobile body 2
The gripper 27 attached to 8 is rotatable in the direction of arrow 107. The positioning of the vertical guide 16 with respect to the guide 15 is controlled by a hydraulic motor 31, the positioning of the moving body 28 or gripper 27 with respect to the guide 16 is controlled by a hydraulic motor 33', and the rotation of the gripper 27 is controlled by the previous implementation. Like the press brake folding machine in the example, it is controlled by a hydraulic motor 29 (FIG. 3). That is, in this folding machine of FIG. 17,
Positioning devices 97, 99 and 1 shown in FIG.
Hydraulic motors 29, 31 and 3 at 01 respectively
3' will be included.

FIG. 18 is a model representing the embodiment of FIG. 17, and in this embodiment, the position of the guide 16 relative to the guide 15 is determined by the rotation center position (xi, yi) of the gripper 27 and the springing angle (θ). (xj) and the position of the gripper 27 relative to the guide 16 (yj)
and the rotation angle (β) of the gripper 27 are determined by the following equations (11), (12), and (13), respectively.

xj=xi...(11) yj=yi...(12) β=90−θ...(13) Note that (xi), (yi), and (θ) are the same as in the folding machine in the previous example. is obtained from equations (6) and (5).

FIG. 19 is a flowchart for explaining control operations corresponding to the press brake type folding machine shown in FIGS. 17 and 18. Hereinafter, with reference to FIG. 19, the operation of the folding machine and a gripper position control method according to another embodiment of the present invention will be described. first step
In S201, the CPU 81 (FIG. 11) controls the hydraulic motors 29 (FIG. 3), 31, and 33' to position the workpiece (plate) relative to the press brake by the robot. next step
At S203, the counter k of the RAM 85 is set to 1. In step S205, CPU81
is a servo system included in the bending machine 1 (not shown)
A command is given to lower the ram 9, that is, the upper die 7b. Steps S207, S209 and
S211 corresponds to steps S107 and S109 in FIG. 16A.
and same as S111. In this embodiment, the vertical guide 16 remains vertical and cannot be rotated, so there is no need to use a flag. Therefore, (xi) and (yi) obtained in step S211 become (xj) and (yj) as they are. Also, the following steps
In S213, the CPU 81 calculates (β) according to equation (13).
seek. In step S215, the CPU 81
A command is given to the drive circuit of the positioning device 99 to move the vertical guide 16 to (xj), and the moving body 2
A command is given to the drive circuit of the positioning device 101 to vertically move the gripper 8 to (yj), and a command is given to the drive circuit of the positioning device 97 to rotate the gripper angle to (β).

Thus, in other embodiments of the invention:
The position of the gripper 27 can be made to follow the jump of the workpiece that occurs in response to the lowering of the upper die 7b. Therefore, the workpiece 100 can be bent while being gripped by the grippers 27.

Note that step S217 in FIG.
S219, S221, S223, S225, S227, S229, S231 and S233 are respectively steps S127, S129, S131, S133, S135, S137 shown in FIG.
Corresponds to S139, S141 and S143.

Next, still another embodiment of the invention will be described.

FIG. 20 shows the main parts of a press brake type folding machine used in still another embodiment of the present invention, in a partially cutaway side view. In this press brake type folding machine, a guide 15' is supported at a predetermined position above the bed 5 of the folding machine 1 by a shaft 14 so as to be rotatable in the direction of arrow 109. Note that this shaft 14 is provided on the robot sliding body 11. A direct movable body 28' is supported by the guide 15' so as to be movable in the direction of arrow 111. The gripper 27 attached to the movable body 28' is rotatable in the direction of arrow 113.
In such an embodiment, the rotation of the guide 15' is controlled by a hydraulic motor 33'', and the rotation of the guide 15' is controlled by a hydraulic motor 33''
5' is controlled by a hydraulic motor 31', and rotation of the gripper 27 is controlled by a hydraulic motor 29 (FIG. 3).
Therefore, in the case of this folding machine, the positioning devices 97, 99 and 101 shown in FIG.
Hydraulic motors 29, 31' and 33'' will be included, respectively.

FIG. 21 is a model of the press brake type folding machine shown in FIG. In FIG. 21, the gripper 27 is
Let the distance to the center of rotation be (L), and guide 1
The position of the center of rotation of the guide 15' in the Y-axis direction relative to the origin is (yo), the angle of the guide 15' is (α),
The angle of the gripper 27 with respect to the moving body 28' is (β)
Then, (α), (L), and (β) are given by equations (14), (15), and (16), respectively.

tanα＝(yi−yo)／xi ∴α＝tan ^-1 (yi−yo)／xi ……(14) cosα＝xi／L ∴L＝xi／cosα ……(15) β＝θ−α …… (16) FIGS. 22A and 22B are flowcharts for explaining the operation of the press brake type folding machine shown in FIGS. 20 and 21. In the flowchart shown in FIGS. 22A and 22B, in steps S313, S315, and S317,
16A, except that (α), (L) and (β) are respectively determined and the drive circuit is controlled according to the determined (α), (L) and (β) in step S319. This is almost the same as the flowchart shown in FIG. 16B, and further explanation will be omitted here.

Next, still another embodiment (fourth embodiment) of the present invention will be described.

FIG. 23 is a perspective view showing the main parts of a press brake type folding machine used in a fourth embodiment of the present invention. In FIG. 23, the press brake type folding machine 1 has a lower mold 7 installed therein.
a, only the upper die 7b and the ram 9 are shown. In front of this folding machine 1, there is a folding machine 1
Similar to the previous folding machine, a pair of loading-side robot mechanisms are arranged at both widthwise ends of the folding machine. In Figure 23,
Although illustration of the unloading robot placed at the rear of the folding machine 1 is omitted, it should be pointed out in advance that it has almost the same configuration as the loading robot. A guide 215 is disposed in front of the folding machine 1 and extends in the front-rear direction of the folding machine 1, that is, in the direction of the arrow 115. This guide 215 includes the movable body 21
8 is supported so as to be movable in the direction of arrow 115. A gripper 227 is attached to this movable body 218, and a supporter 263 that can support a plate-like object or a workpiece thereon.
is installed. The position of this supporter 263 is controlled by an actuator 265. The actuator 265 is also connected to the moving body 218
Of course, it is attached so that it can be moved integrally with it. The moving body 218 is controlled to move in the direction of arrow 115 by a hydraulic motor 231 . That is, a pinion (not shown) is connected to the hydraulic motor 231. This pinion meshes with a rack (not shown) (provided along guide 215). Therefore, as the hydraulic motor 231 rotates, the movable body 218 moves in the X-axis direction on the guide 215 by a rack and pinion (not shown). Further, when the actuator 265 is extended, the supporter 263 is brought into the state shown in the figure, and therefore the plate-like body 100 can be supported on the supporter 263. If actuator 265 is retracted, supporter 263 is returned to its home position. A supporter 264 having the same configuration as the supporter 263 is also provided near the rear end of the guide 215 . This supporter 264 is fixed in the X direction. The supporter 264 is connected to the actuator 2 provided between the supporter 264 and the guide 215.
66 controls its state or position.
A stopper 261 is provided at the rear end of the guide 215. This stopper 261 is connected to a shaft (not shown).
is mounted so as to be rotatable in the direction of arrow 116. The rotation of the stopper 261 is controlled by an actuator 262 provided between the stopper 261 and the guide 215. This actuator 262 is not controlled by a servo system.

A guide 205 is provided in front of the folding machine 1 and parallel to the width direction of the folding machine 1, and a rack 206 is arranged parallel to the guide 205. A pinion 210 is engaged with this rack 206, and this pinion 210 is connected to the hydraulic motor 21.
Connected to the 0 axis. This hydraulic motor 210 is
It is fixed to the support column 211. Therefore, this pinion 210 moves along the rack 206 in the direction of the arrow 11.
This support column 211 responds to displacement in nine directions.
is controlled to move in the direction of arrow 119, that is, in the Y-axis direction. Further, an elevating body 212 is supported by the support column 211 so as to be movable up and down in the direction of arrow 121 (Z-axis direction). This elevating body 212 is controlled to rise and fall relative to the support column 211 by a hydraulic motor 214 attached to the lower part of the bed 5 of the folding machine 1, for example, via a known transmission mechanism (not shown).

The elevating body 212 has a shaft 221 at its upper end.
supports the guide 215 so as to be rotatable in the direction of arrow 117. This guide 215 and the elevating body 2
Two actuators 233 and 234 are connected between the actuator 2 and the guide 215, so that the rotation of the guide 215 in the direction of the arrow 117
33 and 234. The actuators 233 and 234 here are controlled by a hydraulic circuit as shown in FIG.

FIG. 27 is a diagram showing an example of a hydraulic circuit for rotating the guide 215. A pipe line 133 extending from the oil tank 131 is connected to four-port two-position switching valves 137 and 139 via a hydraulic pump 135. Conduits 141 and 143 are connected to switching valves 137 and 139, respectively. Conduit 13
A pipe line including a relief valve 144 is connected between 3 and 143. The 4-port 2-position switching valves 137 and 139 are connected to cylinders 233a and 234a, respectively, and the respective cylinders 23
Pistons 233b and 234b are provided within 3a and 234a. These pistons 233
The diameters of b and 234b are made the same. however,
The strokes of pistons 233b and 234b are different.

Such a hydraulic circuit allows the actuators 233 and 234 to assume a total of four states or positions, for example 0°, 30°, 45° and
The guide 215 can be rotated through a specific angle, such as 60 degrees. Note that the relief valve 144 is
The setting is such that a force that pushes up the workpiece is applied to the workpiece.

Note that the gripper 2 attached to the moving body 218
27 is a third motor controlled by a hydraulic motor 29;
It may have the same configuration as shown in FIG. 4 and FIG. Therefore, the gripper 227
(FIG. 3), it can be rotated in the direction of arrow 123.

Further ahead of the robot is a trolley (not shown).
A plate-shaped body or workpiece 100 is laminated thereon. A single-sheet picking means 125 is provided above the stacked plate-like bodies. The single-piece picking means 125 is mounted, for example, with a vacuum pad 125a facing downward, and the workpieces 100 are sucked by the vacuum pad 125a and taken out one by one. Although not shown, this one-sheet picking means 12
5 can be raised and lowered in the direction of arrow 127 and can be moved in the direction of arrow 129. Therefore, 1
The sheet picking means 125 moves in the direction of arrow 129 while holding the plate-like object 100 on the vacuum pad 125a, and places the workpiece 100 on supports 263 and 264 provided on the robot.

Next, with reference to FIGS. 24 to 26, the outline of the folding operation of the press brake type folding machine shown in FIG. 23 will be explained.

Supporters 263 and 26 as described above
When the plate-like object or workpiece 100 is placed on 4, the one-sheet picking means 125 is returned to its original position,
Subsequently, the guide 215 is rotated about the fulcrum 221 to be in the state shown in FIG. 24. Therefore, one end of the workpiece 100 placed on the supports 263 and 264 is placed on the stopper 26.
1.

Next, as shown in FIG. 25, the guide 215
is returned to the horizontal state, and the movable body 218 is moved by the motor 231. At the same time, actuators 43 and 47 (FIG. 3) are controlled to grip workpiece 100 by gripper 23. Controlling the positions of the moving body 218 and the elevating body 212,
The workpiece 100 is positioned relative to the lower die 7a and the upper die 7b. In this state, the stopper 261 is in a lowered state (home position) by the actuator 262.

Thereafter, the ram 9 of the folding machine 1 is lowered, and the wafer mold 7b is lowered accordingly. A bending load is applied to the positioned workpiece 100 by the upper mold 7b and the lower mold 7a, so that the workpiece 100 jumps up from the horizontal state (26th
figure). Then, the center of rotation of the gripper 27 is sequentially positioned so as to follow this upward movement of the workpiece 100.

28A and 28B are views showing a model of the press brake type folding machine shown in FIG. 23. FIG. 28B is an enlarged version of FIG. 28A. Let (θ) be the angle at which the workpiece 100 gripped by the gripper 27 jumps up in response to the bending load applied by the upper die 7a. The distance between the rotation center of the gripper 227 and the rotation center 221 of the guide 215 is (Ro)
The distance when the workpiece 100 is raised is (Rx). The distance between the bending point and the rotation center 221 of the guide 215 is (lo)
Let the positions of the rotation center 221 of the guide 215 in the Y-axis direction be (yo) and (yj). (yo) indicates the case where the workpiece 100, that is, the guide 215 is in a horizontal state, and (yj) indicates the case where the workpiece 100 is in a horizontal state.
0 indicates the position when folded. In FIG. 28B, (yl) indicates the distance in the Y-axis direction of the workpiece 100 at a position corresponding to the center of rotation of the guide 215, and (yk) indicates the difference between (yj) and (yl). (rx) indicates the distance from the bending point to the rotation center 221 of the guide 215, and (rx')
is related to the flip-up angle (θ) and represents the amount of longitudinal displacement of the guide 215 caused by the distance yo between the guide 215 and the workpiece 100.

From FIGS. 28A and 28B, it can be seen that the following equations (17), (18), and (19) hold true in the folding machine of FIG. 23, respectively.

rx＝lo／cosθ rx′＝yotanθ yk＝yo／cosθ l＝lotanθ Rx＋rx−rx′＝Ro＋lo ……(17) ∴Rx＝Ro＋lo−rx＋rx′ ……(18) yj＝yl−yk＋yo ……(19) Organize (17), (18) and (19) and guide 215
Letting the position of the rotation center 221 in the Y-axis direction be (yj) and the position of the moving body 218 in the x-axis direction be (Rx), they are given by equations (20) and (21), respectively.

yi=lotanθ−(yo/cosθ)+yo……(20) Rx=Ro+lo−(lo/cosθ)+yotanθ……(21) As is clear from equation (5) above, (θ) is
It is a function of the height (h) of the upper die 7b. Therefore, by determining the jump angle (θ) based on the upper part of this height (h), the control element (yj)
and (Rx) can be found.

In this folding machine, the bus 83 shown in FIG.
actuators, that is, switching valves 137 and 139 (second
A circuit for driving (Figure 7) is connected,
Instructions are given to that circuit from the CPU 81.
Further, a hydraulic motor 214 for controlling the position (yj) of the elevating body 212 and a hydraulic motor 231 for controlling the position (Rx) of the movable body 218 are included in the positioning devices 99 and 97 (FIG. 11), respectively. shall be taken as a thing.

29A and 29B are flowcharts for explaining the operation of the press brake type folding machine shown in FIG. 23. In the operation shown in FIGS. 29A and 29B, the second
Steps S411, S413 and S415 shown in Figure 9A
, (θ), (yj) and (Rx), respectively
16A and 1 except that the follow-up control is performed in step S417.
It is almost the same as Figure 6B. Therefore, only these steps S411 to S417 will be explained here.

In S411, the bounce angle (θ) of the workpiece is determined based on equation (5). And the steps
In S413, the position (yj) of the rotation center 221 of the guide 215 in the Y-axis direction is determined based on the determined (θ) and other data. Then, in step S415, the position (Rx) of the moving object 218 is determined. In step S417, first, depending on the angle to be bent (this has been taught in advance), one of the sets of actuators 233 and 234 shown in FIG. 27 is selected, and the corresponding four-port switching valve 137 or 13 is selected.
Give instructions to 9. Then, the guide 215 is tilted or rotated, for example, at 0°, 30°, 45°, or 60°. Subsequently, the CPU 81 gives a command to the drive circuit of the positioning device 97 in order to move the position of the elevating body 212 in the Y-axis direction to (yj). At the same time, a command is given to the drive circuit of the positioning device 99 to move the moving body 218 to (Rx).

In each of the embodiments described above, the workpiece is gripped by the gripper means during each of the series of bending operations, that is, during the positioning and bending operations of the workpiece. However, the invention may be such that the workpiece can be gripped by the gripper means at least during the bending operation. Therefore, for example, when a turntable is installed below the middle between the left and right guides 215 to perform bending operations in different bending line directions, the workpiece is bent along the bending line in a certain direction, and then the gripper means is released to hold the workpiece. The device may be placed on a turntable and rotated to grip and position the workpiece by gripper means in the appropriate position in the direction of another folding line and then fold it. The point is that the gripper means only needs to keep gripping the workpiece during the bending operation, ie, while the bending load is applied to the workpiece by the upper die.

[Effects of the Invention] As described above, the workpiece or plate jumps up depending on the height of the upper die of the bending machine. According to the present invention, the position of the gripper means can be made to follow such a jump. For positional control, the gripper means allows the workpiece to be gripped and bent during the bending motion. Therefore, there is no need to change the workpiece by gripper means, and control is simple. Moreover,
Since the workpiece remains gripped by the gripper means during the bending operation, the workpiece can be bent with great precision.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view showing a press brake type folding machine used in one embodiment of the present invention. FIG. 2 is a plan view taken along the line - in FIG. 1. 3 and 4 are diagrams showing details of the gripper means, with FIG. 3 showing a partially cutaway front view thereof, and FIG. 4 showing a partially cutaway plan view thereof. FIG. 5 is a diagram illustrating the operation of the supporter provided on the standby conveyor. 6, 7, and 8 are diagrams for explaining the operation of the gripper means gripping a workpiece in the folding machine shown in FIG. 1. FIG. 9 shows the positioning of the workpiece. FIG. 10 shows the bending operation. 11th
The figure is a block diagram showing an example of an electric circuit in an automatic sheet folding device used in the present invention. FIG. 12 is a diagram showing an example of a workpiece to be bent. FIG. 13 is a model showing the relationship between the upper die, the lower die, and the workpiece during the bending operation. FIG. 14 is a model for calculating the position to be controlled of the gripper means. 1st
FIG. 5 is a model for obtaining data necessary for controlling the folding machine shown in FIG. 1. 16A and 16B are flowcharts for explaining the operation of the folding machine shown in FIG. 1. FIG. 17 is a partially cutaway side view showing the main part of a press brake type folding machine used in another embodiment of the present invention. FIG. 18 is a model for obtaining data necessary for controlling the folding machine shown in FIG. 17. FIG. 19 is a flowchart for explaining the operation of the folding machine shown in FIG. 17. FIG. 20 is a partially cutaway side view showing a main part of a press brake type folding machine used in still another embodiment of the present invention. FIG. 21 is a model for obtaining data necessary for controlling the folding machine shown in FIG. 20. 22A and 22B are flowcharts for explaining the operation of the folding machine shown in FIG. 20. FIG. 23 is a perspective view showing the main parts of a press brake type folding machine used in still another embodiment of the present invention. Figure 24 to 2
6 is a diagram sequentially showing a series of folding operations in the folding machine shown in FIG. 23. 27th
The figure shows an example of a hydraulic circuit of an actuator for rotating the guide. Figures 28A and 28
Figure B is a model for obtaining data necessary for control in the folding machine shown in Figure 23. 29th
Figures A and 29B are flowcharts for explaining the operation of the folding machine shown in Figure 23. In the figure, 1 is a press brake type bending machine, 7a is a lower mold, 7b is an upper mold, 27 is a gripper,
29, 31, 33, 31', 33', 33'', 21
0 indicates a hydraulic motor.

Claims (1)

[Scope of Claims] 1. A bending machine having a lower die and an upper die for folding a plate-shaped body, a gripper disposed at least in front of the folding machine to grip the plate-shaped body, and a gripper arranged at least in front of the folding machine to grip the plate-shaped body; In an automatic plate-shaped object folding device equipped with a gripper displacement mechanism for moving the folding machine in a vertical plane in the front-rear direction and around a horizontal axis perpendicular to the vertical plane, the gripper is The method includes detecting the height (h) of the upper mold relative to the lower mold, calculating the spring-up angle (θ) of the plate-shaped body during the bending operation from the detected height, and calculating the calculated height (h) of the plate-shaped body during the bending operation. The gripper displacement mechanism is position-controlled based on the calculated following position, and the position of the gripper is thereby caused to follow the springing up of the plate-shaped body. characterized by having done
A gripper position control method in an automatic sheet bending device.