JP5196566B2 - Bending method and apparatus by robot - Google Patents

Description

The present invention relates to a bending method by a robot and an apparatus therefor in an automatic machining system in which a bending machine having a punch and a die and a robot are combined.

Conventionally, as shown in FIG. 9, in an automatic machining system in which a bending machine (for example, press brake) having a punch P and a die D is combined with a robot, when a workpiece W after bending is taken out by a robot, a target angle is obtained. The gripper G of the robot is positioned at a position (for example, 90 °) and the work W is gripped.

However, the workpiece W is considered to be springback, and is at an angular position of, for example, 88 ° smaller than the target angle.

Therefore, the workpiece W and the gripper G are at different angular positions, and when the gripper G grips the workpiece W in this state, the workpiece W is folded back as shown in the figure.

As a result, if the processing is continued, the bending process is performed with the waist folded, so that a defective product is generated, and the gripper G is overloaded and may be damaged.

In order to solve this problem, as disclosed in, for example, Japanese Patent No. 3115947, a means has been developed in which a gripper of a robot grips a workpiece and performs circular interpolation during bending.
Japanese Patent No. 3115947

  The means disclosed in the above-mentioned Japanese Patent No. 3115947 actually requires a gripper arc follow-up speed synchronized with the work jumping speed in order to grip and follow the work.

In this case, if the workpiece and the gripper are even out of sync, the workpiece may be broken as described above.

Therefore, as disclosed in Japanese Patent No. 3115947, a half-clamped system is used to follow the workpiece jumping with the gripper opened.

That is, conventionally, since there is a difference between the target angle (90 °) of the robot gripper and the bending angle (88 °) before the workpiece is spring-backed, hip folding occurs when the gripper grips the workpiece.

And as the work has a larger amount of springback, the above described hip breakage tends to increase (FIG. 9).

If the said subject is explained in full detail, it will come to show in FIGS. Here, FIG. 10 shows a case where the workpiece W is a thin plate (for example, 1 mm), and FIG. 11 shows a case where the workpiece W is a thick plate (for example, 6 mm).

First, when the workpiece W is a thin plate (FIG. 10), at the end of processing, while the gripper G (FIG. 10A) is opened, the workpiece W is positioned at a target angle of 90 °. As described above, W is bent at 88 ° by considering the spring back.

Therefore, in this state, if the gripper G (FIG. 10 (B)) is closed and grips the workpiece W, the workpiece W is in contact with the portion W1 gripped by the gripper G and the V groove of the die D as shown in the figure. The direction is different from the portion W2 on the D1 side, and the thin workpiece W is bent, and the workpiece W is bent as described above.

In other words, among the workpiece W bent at 88 °, the right portion is caught by the upper edge of the V groove D1 of the die D as shown in the figure, and the waist of the workpiece W is bent. If the processing is continued as it is, defective products are generated.

Next, when the workpiece W is a thick plate (FIG. 11), similarly, at the end of machining, the workpiece W is positioned at a target angle of 90 ° with the gripper G (FIG. 11A) open. On the other hand, the workpiece W is similarly bent to 88 ° by considering the spring back.

However, even if the gripper G (FIG. 11B) closes and grips the workpiece W in this state, the workpiece W does not bend as shown in the figure. A load is applied.

In other words, since the workpiece W bent at 88 ° does not bend as shown in the figure, the gripper G is overloaded, the entire gripper G is distorted, and may eventually be damaged. .

Thus, conventionally, when the workpiece W is gripped by the gripper G at an angular position of 90 ° while the workpiece W is being pressed (the bending angle of the workpiece W is 88 ° at this time), the angular difference between the two (2 In the case of a thin plate, the workpiece W is folded back (FIG. 10 (B)), and in the case of a thick plate, the gripper G is overloaded (FIG. 11 (°)). B)).

And as a means for solving this subject, there are a first means (FIGS. 12 to 13) and a second means (FIGS. 14 to 15). The bending angle of the workpiece W is 88 °), and means for gripping the workpiece W with the gripper G at an angular position of 88 °. The latter is after the unloading of the workpiece W (the load received by the workpiece W at this time is zero). , A means for gripping the workpiece W with the gripper G at an angular position of 88 °.

Hereinafter, the first means (FIGS. 12 to 13) and the second means (FIGS. 14 to 15) will be described separately for the case where the workpiece W is a thin plate and the case of a thick plate.

(1) About the first means (FIGS. 12 to 13).
(1) -A When the workpiece W is a thin plate (FIG. 12).
When the workpiece W is a thin plate, at the end of machining, the workpiece W is positioned at an angular position of 88 ° with the gripper G (FIG. 12A) open. By doing so, it is bent to 88 °.

Accordingly, in this state, if the gripper G (FIG. 12B) is closed and the workpiece W is gripped, the workpiece W is the same as the orientation of the gripper G as shown in the figure. The work W does not break.

However, when the punch P (FIG. 12 (C)) is raised and the load of the workpiece W becomes zero, the workpiece W returns to the target angle of 90 ° by the spring back, so the portion gripped by the gripper G The direction of W3 and the part W4 on the die D side are different from each other, and the thin workpiece W is bent and the workpiece W is bent.

In other words, since the workpiece W returned to 90 ° (FIG. 12C) is gripped by the gripper G positioned at an angular position of 88 °, as shown in the drawing, the workpiece W which is a thin plate is bent back. If it is generated and processing continues, defective products will be generated.

(1) -B When the workpiece W is a thick plate (FIG. 13).
Similarly, when the workpiece W is a thick plate, the workpiece W is similarly positioned at the position of 88 ° with the gripper G (FIG. 13A) opened at the end of processing. By considering the spring back, it is bent at 88 °.

Accordingly, in this state, if the gripper G (FIG. 13B) is closed and the workpiece W is gripped, the workpiece W is the same as the orientation of the gripper G as shown in the figure. However, the gripper G is not overloaded.

However, when the punch P (FIG. 13C) is raised and the load of the workpiece W becomes zero, the workpiece W returns to the target angle of 90 ° by the spring back, and the workpiece W is a thick plate. Therefore, the gripper G is overloaded.

In other words, the workpiece W returned to 90 ° (FIG. 13C) is a thick plate and does not bend as shown in the figure. On the contrary, the gripper G is overloaded, and the entire gripper G It may become distorted and eventually be damaged.

As described above, the first means (FIGS. 12 to 13) is configured so that the workpiece W is being pressurized (at this time, the workpiece W of the workpiece W) regardless of whether the workpiece W is a thin plate (FIG. 12) or a thick plate (FIG. 13). If the bending angle is 88 ° (FIGS. 12B and 13B), even if the workpiece W is gripped by the gripper G at an angular position of 88 °, the orientation of the workpiece W and the gripper G Are the same, so there is no inconvenience, but at the time of unloading (at this time the load received by the workpiece W is zero), the workpiece W returns to the target angle of 90 ° (FIG. 12 (C), FIG. 13 ( C)), the difference in angle between the two (2 ° = 90 ° −88 °) causes the workpiece W to bend in the case of a thin plate, and the gripper G is overloaded in the case of a thick plate.

Therefore, the first means (FIGS. 12 to 13) is not appropriate as a means for solving the problem.

(2) About the second means (FIGS. 14 to 15).
(2) -A When the workpiece W is a thin plate (FIG. 14).
When the workpiece W is a thin plate, the workpiece W is similarly positioned at an angular position of 88 ° with the gripper G (FIG. 14A) open at the end of machining, while the workpiece W is also considered for spring back. By doing so, it is bent to 88 °.

However, when the punch P (FIG. 14B) is lifted and unloaded, the load of the workpiece W becomes zero, and the workpiece W returns to the target angle of 90 ° by the spring back. When gripping the workpiece W returned to 90 ° with the gripper G positioned at the position (FIG. 14C), the direction of the portion W5 gripped by the gripper G and the portion W6 on the die D side are different. The thin workpiece W is bent and the workpiece W is bent.

In other words, since the workpiece W returned to 90 ° (FIG. 14C) is gripped by the gripper G positioned at an angular position of 88 °, as shown in FIG. If it is generated and processing continues, defective products will be generated.

(2) -B When the workpiece W is a thick plate (FIG. 15).
Similarly, when the workpiece W is a thick plate, the workpiece W is similarly positioned at the position of 88 ° with the gripper G (FIG. 15A) open at the end of machining. By considering the spring back, it is bent at 88 °.

However, similarly, when the punch P (FIG. 15B) is lifted and unloaded, the load of the workpiece W becomes zero, and the workpiece W returns to the target angle of 90 ° by the spring back, and the workpiece W Since W is a thick plate and does not bend even when gripped by the gripper G positioned at 88 ° (FIG. 15C), the gripper G is overloaded.

In other words, the workpiece W returned to 90 ° (FIG. 15C) is a thick plate and does not bend as shown in the figure. On the contrary, the gripper G is overloaded, and the entire gripper G It may become distorted and eventually be damaged.

As described above, the second means (FIGS. 14 to 15) is configured so that after the workpiece W is unloaded (at this time, the workpiece W is either a thin plate (FIG. 14) or a thick plate (FIG. 15)). Since the load received is zero), it returns to the target angle of 90 ° (FIGS. 14C and 15C). Even if the workpiece W is gripped by the gripper G at an angular position of 88 °, The direction of the gripper G is different, and the workpiece W is folded back in the case of a thin plate, and the gripper G is overloaded in the case of a thick plate by an angle difference between them (2 ° = 90 ° -88 °). become.

Therefore, the said 2nd means (FIGS. 14-15) is not suitable as a means for solving a problem like the said 1st means (FIGS. 12-13).

It is an object of the present invention to eliminate a positioning error between a robot gripper and a workpiece, thereby eliminating the occurrence of a defective product due to the hip folding of the workpiece and preventing the robot gripper from being damaged due to an overload. A method and apparatus are provided.

In order to solve the above-mentioned problems, the present invention provides, as described in claim 1,
In a method of bending a workpiece W gripped by a gripper 14 of a robot 13 by activating a ram composed of an upper table 20 or a lower table 21 and cooperation of a punch P and a die D,
(1) After the ram 20 is activated and the punch P comes into contact with the workpiece W gripped by the robot gripper 14, the workpiece W is released from the robot gripper 14,
(2) The robot gripper 14 is made to follow the jumping motion of the workpiece W, and when the robot gripper 14 reaches the target angular position, the robot gripper 14 stops there and waits.
(3) After that, the ram 20 reaches the limit position and stops, and after the bending process in the process is completed, the ram 20 starts in the reverse direction, and the load of the workpiece W becomes zero, and at the same time the target angular position is reached. A bending method by a robot, wherein the waiting robot gripper 14 grips the workpiece W;
And, as described in claim 3, the present invention provides
In the bending apparatus by the robot used directly for carrying out the bending method by the robot according to claim 1,
During the bending process, the robot gripper 14 is made to follow the workpiece jumping operation with the workpiece W released, and is kept at the target angle position (90 °) (FIG. 5B). After the bending process is finished, the load becomes zero. A robot bending machine having a robot controller 1 (FIG. 1) having the robot W held by the robot gripper 14 waiting at the target angular position (90 °) (FIG. 6B). Take measures.

  According to the configuration of the present invention described above, if the robot gripper 14 is kept waiting at a target angular position of 90 ° in advance (FIGS. 4A to 4C), for example, the upper table 20 which is a ram. When the upper table 20 reaches the lower limit position and stops and the bending process of the process is completed (FIG. 4B), the bending angle at that time is, for example, 88 ° in anticipation of the spring back. Then, when the upper table 20 is lifted, the load of the workpiece W becomes zero, and the bending angle of the workpiece W becomes 90 ° at that moment. Therefore, the robot gripper 14 and the workpiece that have been waiting in advance at the target angle position (90 °). W is positioned at the same angular position, and there is no positioning error between them (FIG. 4 (C)). Therefore, the conventional work W (FIGS. 9 to 11) is free from hip breakage. Te, defective products are eliminated, damage to the robot gripper is prevented.

The above operation is performed by the robot controller 1 (FIG. 1) that constitutes the bending apparatus by the robot according to the present invention, and the robot controller 1 performs the spring back (work W (FIG. 5B)) during bending. Until the robot gripper 14 is bent to 88 ° (the limit angle)), the workpiece gripper 14 follows the workpiece jumping motion with the workpiece W released, and waits at the target angle position (90 °). (Since the workpiece W (FIG. 6B) is unloaded and the load becomes zero, the workpiece W returns to 90 ° (target angle) based on the spring back). 90 °), the workpiece gripper 14 is held in the same direction, so that the orientation of the workpiece W and the robot gripper 14 is the same, there is no difference in the angle between them, and the workpiece W is a thin plate. Will not bend and will not bend, and if the workpiece W is a thick plate, the robot gripper 14 will not be overloaded.

  As described above, according to the present invention, by eliminating the positioning error between the robot gripper and the workpiece, it is possible to eliminate the occurrence of defective products due to the workpiece being folded back and to prevent damage due to overload on the robot gripper. There is an effect of providing a bending method and apparatus by a robot.

Hereinafter, the present invention will be described with reference to the accompanying drawings by embodiments.
FIG. 1 is an overall view of the present invention, and a bending system using a robot shown in FIG. 1 inputs, for example, CAD information, which is product information J, from an NC device 10 of a bending device 11, and performs bending order, molds P, D. In addition to calculating the die layout and the like and calculating the trajectory of the work following operation of the robot 13 for each process (bending order) (step 101 to step 103 in FIG. 7), actual bending is performed (FIG. 7). Step 104, FIG. 8).

  The bending apparatus 11 (FIG. 1) in this case includes a press brake, and as is well known, has a punch P mounted on the upper table 20 and a die D mounted on the lower table 21. ing.

  A back gauge is disposed behind the lower table 21, and the back gauge abutment 23 is attached to a slider 24. The slider 24 is slidably coupled to a stretch 25 extending in the left-right direction (the direction perpendicular to the paper surface). doing.

  In addition, side plates (not shown) are installed on both sides of the press brake, and each side plate is provided with a ram drive source including a hydraulic cylinder 7 and the like. In the descending press brake, the upper table 20 is lowered. Thus, in the lift press brake, the workpiece W is bent by the punch P and the die D described above when the lower table 21 is lifted.

  A robot 13 is installed in front of the lower table 21.

  The robot 13 has a gripper 14 at the tip of an arm 19, and the gripper 14 is composed of an upper gripper 14A that can move up and down and a fixed lower gripper 14B as shown in FIG. The workpiece W is gripped.

  With this configuration, when the robot 13 receives a control signal S1 from a robot controller 1 (FIG. 1), which will be described later, for example, after positioning the work W gripped by the gripper 14 (FIG. 3 (A)), the robot 13 When P reaches the pinching point, various operations such as raising the upper gripper 14A to release the workpiece W (FIG. 3B) are performed.

  That is, the robot 13 (FIG. 1) is a bending robot, and receives a workpiece as a material from a loading / unloading robot (not shown) installed on the side of the bending robot 13 and inserts it into the machine body. When processed, the product is delivered to the carry-in / out robot.

On the other hand, a pressure sensor 2 is installed in the hydraulic cylinder 7, and it is possible to detect whether or not the load of the workpiece W is zero using the pressure sensor 2 (step 104J in FIG. 8).

That is, when the upper table 20 as a ram descends and reaches a predetermined stroke and stops once (steps 104E to 104G in FIG. 8), the workpiece W is bent to 88 ° in view of the spring back (see FIG. 4 (B)), the workpiece W receives a predetermined load from the machine body side, and the machine body side receives a reaction force from the workpiece W, and the pressure sensor 2 exhibits a predetermined value.

However, if the ram 20 is then raised (FIG. 4 (C)), the load received by the workpiece W decreases, eventually the load becomes zero, and the reaction force received by the machine body from the workpiece W also becomes zero. Can be detected when the pressure sensor 2 becomes zero (YES in step 104J in FIG. 8).

The fact that the load received by the workpiece W has become zero means that the bending angle of the workpiece W has been changed from 88 ° (FIG. 4B) to 90 ° (FIG. 4C) due to the springback. It became an angle.

Therefore, at this time, the robot gripper 14 that has stopped at the target angular position in advance and is waiting there (FIG. 4C) and the workpiece W are positioned at the same angular position. The positioning error is eliminated.

For this reason, according to the present invention, by eliminating the positioning error between the robot gripper and the workpiece, it is possible to eliminate the occurrence of defective products due to the hip folding of the workpiece and to prevent damage due to overload on the robot gripper. There is an effect of providing a bending method by.

Further, in the bending apparatus 11 (FIG. 1), a stroke sensor 3 is installed so that the stroke of the ram 20 is detected (step 104F in FIG. 8).

Further, the bending device 11 (FIG. 1) is provided with a hydraulic pump 4 for supplying hydraulic oil to the hydraulic cylinder 7 and is controlled via a servo amplifier 6 and a servo motor 5 by a bending control unit 10G described later. The

The press brake having the above-described configuration (FIG. 1) includes an NC device 10 that controls the press brake and the robot 13 described above through the robot controller 1.

The NC device 10 includes a CPU 10A, an input / output unit 10B, a storage unit 10C, a machining information calculation unit 10D, a sensor control unit 10E, a back gauge control unit 10F, and a bending process control unit 10G.

  The CPU 10A performs overall control of the entire apparatus shown in FIG. 1, such as the machining information calculation unit 10D, the sensor control unit 10E, and the back gauge control unit 10F.

  The input / output unit 10B is, for example, an operation panel (not shown) provided on the upper table 20, and by inputting product information J including CAD information, the processing information calculation unit 10D causes the workpiece W to be processed to be processed. Bending order (process), molds used for each bending order, and the like are calculated (step 101 to step 103 in FIG. 7).

The input / output unit 10B (FIG. 1) exchanges a bidirectional signal S2 with the robot controller 1, so that the CPU 10A always keeps the state of the robot 13 described above (for example, FIGS. 3 to 4). It can be monitored.

The storage unit 10C stores CAD information input via the input / output unit 10B, and stores a machining program according to the present invention (for example, corresponding to FIGS. 7 to 8).

  The machining information calculation unit 10D (FIG. 1), based on the CAD information (step 101 in FIG. 7) input via the input / output unit 10B, as described above, the bending order, the mold, the mold layout (Step 102 in FIG. 7) and information necessary for bending the workpiece W, such as calculating the trajectory of the workpiece following operation of the robot 13 (step 103 in FIG. 7) for each process (bending order). To do.

  In this case, the trajectory F (following trajectory F) of the workpiece following operation of the robot 13 (FIG. 3C) is calculated based on the workpiece posture state diagram (process diagram).

  That is, the machining information calculation unit 10D (FIG. 1) uses the CAD information to determine the workpiece posture state including the posture at the time of positioning of the workpiece W (FIG. 3A) and the posture at the time of jumping up (FIG. 3C). A diagram is created, and the following trajectory F of the robot 13 is calculated based on the created workpiece posture state diagram.

  The sensor control unit 10E (FIG. 1) controls the pressure sensor 2 and the stroke sensor 3 described above, and notifies the CPU 10A of values exhibited by each sensor.

As a result, when the value of the pressure sensor 2 is zero, the CPU 10A assumes that the load of the workpiece W is zero (YES in step 104J in FIG. 8), and causes the robot gripper 14 that has been waiting in advance to the target angular position. The workpiece W is gripped (step 104K in FIG. 8, FIG. 4C).

In addition, after the ram 20 is lowered (step 104E in FIG. 8), the CPU 10A expects a springback when the value of the stroke sensor 3 reaches a predetermined stroke value (YES in step 104F in FIG. 8). Assuming that the workpiece W has been bent to 88 ° (FIG. 4B), the hydraulic cylinder 7 is controlled via the bending control unit 10G (FIG. 1) to stop the ram 20 (step 104G in FIG. 8). ).

The back gauge control unit 10F (FIG. 1) positions the above-described back gauge abutment 23 at a predetermined position in advance, and the bending process control unit 10G rotates the hydraulic pump 4 via the servo amplifier 6 and the servo motor 5. By controlling the direction of the hydraulic oil supplied to the hydraulic cylinder 7, the upper table 20 (FIG. 2) is moved up and down and the workpiece gripped by the robot gripper 14 by the cooperation of the punch P and the die D B is bent.

The operation of the present invention having the above configuration will be described below with reference to FIGS.

(1) The operation until the locus of the workpiece following operation of the robot 13 is calculated.
In step 101 of FIG. 7, CAD information is input. In step 102, bending order, mold, mold layout, and the like are calculated. In step 103, the robot 13 performs the work following operation for each process (bending order). Calculate the trajectory.

  That is, when the CPU 10A detects that CAD information has been input via the input / output unit 10B (FIG. 1), it controls the machining information calculation unit 10D to control the bending order, mold, mold layout, and D Information necessary for bending the workpiece W, such as values and L values, is calculated, and the following trajectory F of the robot 13 (FIG. 3C) is calculated for each process.

(2) Bending operation.
In step 104 of FIG. 7, a bending operation is performed, the details of which are shown in FIG.

(2) -A Operation until it is determined whether or not the punch P has reached the pinching point.
First, the work W is carried in by the robot 13 (step 104A in FIG. 8), the work W is positioned (step 104B in FIG. 8), the ram 20 is lowered (step 104C in FIG. 8), and the punch P is pinched. It is determined whether or not the point has been reached (step 104D in FIG. 8).

That is, the CPU 10A (FIG. 1) instructs the robot controller 1 via the input / output unit 10B when detecting that the machining information calculation unit 10D has calculated the following trajectory F of the robot 13 in step 103 of FIG. By controlling the robot 13, the gripper 14 (FIG. 3A) grips the workpiece W, inserts the workpiece W from between the punch P and the die D, and loads it into the press brake. The ram 20 (FIG. 2) is lowered via the bending control unit 10G (FIG. 1), and the punch P (FIG. 3 (B)) reaches the pinching point. In other words, it is determined whether or not the punch P is in contact with the workpiece W on the die D.

(2) -B The operation until the robot gripper 14 stands by at the target angular position (90 °) after the punch P reaches the pinching point.
After the punch P reaches the pinching point, the gripper 14 of the robot 13 performs an operation unique to the present invention.

When the punch P reaches the pinching point (YES in step 104D in FIG. 8), the robot gripper 14 releases the workpiece W (step 104L in FIG. 8), and then follows the jumping operation of the workpiece W (step 104M in FIG. 8). ) When the angle of the robot gripper 14 reaches, for example, 90 ° which is the target angle position (YES in Step 104N in FIG. 8), the robot gripper 14 is stopped at the 90 ° position and waits there ( Step 104P in FIG.

That is, when the CPU 10A (FIG. 1) detects that the punch P has reached the pinching point via the sensor control unit 10E (FIG. 3B), the CPU 10A moves the upper gripper 14A via the robot controller 1 (FIG. 1). (FIG. 3 (B)) After slightly raising and releasing the workpiece W in the half clamp state, the robot gripper 14 is made to follow the jumping-up operation of the workpiece W (FIG. 3 (C)), which is the target angular position 90. When it reaches ° (FIG. 4A), it stops and waits.

(2) -C The operation until the work gripper 14 is gripped after the robot gripper 14 waits at the target angular position (90 °).
After the robot gripper 14 reaches the target angular position (FIG. 4A), the workpiece W immediately after the springback bent at 90 ° is gripped (FIG. 4B → FIGS. 4C and 8). Step 104K).

In this case, when the operation after the punch P reaches the pinching point (FIG. 3B) is focused on the ram 20, the operation is as follows.

That is, even after the pinching point, the ram 20 continues to descend (FIG. 3C), and even after the workpiece W is bent to the target angle of 90 ° (FIG. 4A), it further descends (FIG. 4). 4 (B)),
When the workpiece P is bent to 88 ° by the punch P reaching the D value and the ram 20 reaching a predetermined stroke, the ram 20 stops.

Thereafter, the ram 20 is lifted (FIG. 4C), the load of the workpiece W becomes zero, and the workpiece W having a bending angle of 88 ° to 90 ° that is considered to have caused the spring back is defined as the target. The robot gripper 14 that has been waiting at the angular position grips it.

The operation flow of the ram 20 after the punch P reaches the pinching point is described in steps 104E to 104H in FIG.

In this way, the bending method by the robot according to the present invention is performed, and when all the processing is completed (YES in step 105 in FIG. 7), the operation is completed (END).

As described above (claim 3), the robot bending apparatus according to the present invention, which is directly used for carrying out the bending method by the robot according to the present invention, is specifically the robot controller 1 (FIG. 1). Yes, during the bending process (FIG. 5B), the robot controller 1 causes the robot gripper 14 to follow the workpiece jumping operation with the workpiece W released and waits at the target angular position (90 °) for bending. After completion of the machining (FIG. 6B), the workpiece W with zero load is gripped by the robot gripper 14 that is placed on standby at the target angular position (90 °).

According to the robot controller 1 of the present invention, the workpiece W that has been unloaded and the load has become zero and the bending angle has returned to the target angle of 90 ° (FIG. 6B) is set to the target angle position (90 °). Since the workpiece gripper 14 is held by the robot gripper 14, the orientation of the workpiece W and the robot gripper 14 is the same, there is no difference in the angle between them, and when the workpiece W is a thin plate, it will not bend and waist will not be bent. When the workpiece W is a thick plate, the robot gripper 14 is not overloaded.

The robot controller 1 (FIG. 1) is connected to an NC device 10, which has a machining information calculation unit 10D, a bending control unit 10G, and a sensor control unit 10E. It cooperates with these processing information calculation units 10D and the like.

For example, the machining information calculation unit 10D (FIG. 1) calculates a process (bending order), a mold, and a mold layout (step 102 in FIG. 7), and a track F (Following action F () of the robot for each process. 3 (C)) is calculated (step 103 in FIG. 7), and these pieces of information are stored in the storage unit 10C described above.

The robot controller 1 refers to the information stored in the storage unit 10C (FIG. 1) when the robot gripper 14 (FIG. 5) follows the workpiece jumping operation (step 104M in FIG. 8).

That is, first, the position of the robot gripper 14 in the left-right direction (X-axis direction (direction perpendicular to the paper surface) in FIG. 1) is the mold layout of the process calculated by the machining information calculation unit 10D, in other words, the upper and lower tables 20 , 21 corresponds to the arrangement positions of the molds P, D.

Therefore, the robot controller 1 guides the robot gripper 14 to the position of the mold layout of the process, and stops there.

Next, the position of the robot gripper 14 in the front-rear direction and the vertical direction (the Y-axis direction and the Z-axis direction in FIG. 1) is the locus F (FIG. 3) of the robot's work following operation calculated by the machining information calculation unit 10D. (C)), in other words, corresponds to the following trajectory F.

Therefore, the robot controller 1 causes the robot gripper 14 to follow the workpiece jumping movement along the following locus F (FIG. 3C) of the process, and when the target angular position (90 °) is reached, Stop and wait (FIG. 5B).

On the other hand, the bending process control unit 10G (FIG. 1) drives and controls the ram 20 so that the workpiece W is bent by a target angle (90 °).

The sensor control unit 10E (FIG. 1) controls the drive of the pressure sensor 2 so that the pressure sensor 2 detects the load received by the work W, or the stroke sensor 3 detects the stroke of the ram 2. And drive control of the stroke sensor 3

Then, as described above (step 104M in FIG. 8), the robot controller 1 causes the robot gripper 14 to follow the workpiece jumping operation (FIG. 5). After the ram 20 is lowered (step 104C in FIG. 8), the sensor control unit 10E has detected that the pinching point of the punch P has been reached (YES in step 104D in FIG. 8).

That is, first, the bending control unit 10G controls the rotation of the hydraulic pump 4 via the servo amplifier 6 and the servo motor 5 (FIG. 1), and the direction of the hydraulic oil supplied to the hydraulic cylinder 7 that is a ram drive source. By controlling, the ram 20 is lowered (step 104C in FIG. 8).

Next, as the ram 20 descends, the punch P mounted on the ram 20 comes into contact with the workpiece W on the die D, and the stroke sensor 3 detects the stroke of the ram 20 at this time. By determining the value of the stroke sensor 3 via the sensor control unit 10E, it is determined that the punch P has reached the pinching point (YES in step 104D in FIG. 8).

Then, the robot controller 1 (FIG. 1) notifies that the punch P has reached the pinching point (YES in step 104D in FIG. 8) through the sensor control unit 10E and (FIG. 1) the input / output unit 10B. Thereafter (step 104L to step 104M in FIG. 8), as described above, the robot gripper 14 is caused to follow the workpiece jumping operation.

In addition, after the pinching point (YES in step 104D in FIG. 8), the robot controller 1 causes the robot gripper 14 to follow the workpiece jumping motion as described above, and when it reaches the target angular position (90 °), In the meantime, the bending control unit 10G and the sensor control unit 10E drive and control the ram 20 (FIG. 1), the pressure sensor 2, and the stroke sensor 3. Thus, the following operation is performed (104E to 104J in FIG. 8).

That is, the bending control unit 10G (FIG. 1) similarly continues to lower the ram 20 (104E in FIG. 8), and that the ram 20 has reached a predetermined stroke (YES in 104F in FIG. 8). Since the sensor control unit 10E (FIG. 1) knows by determining the value of the stroke sensor 3, the bending control unit 10G (FIG. 1) considers that the ram 20 has reached the limit position, and the ram 20 20 is stopped (step 104G in FIG. 8), and at this point, the workpiece W is bent (88 ° (limit angle)) in anticipation of springback.

Thereafter, the bending control unit 10G (FIG. 1) raises the ram 20 (step 104H in FIG. 8), so that the punch P is separated from the work W (FIG. 6A). Is unloaded and the load becomes zero, and this can be understood by the sensor control unit 10E (FIG. 1) discriminating the value of the pressure sensor 2 (step 104J in FIG. 8). The bending angle (FIG. 6A) returns to 90 ° (target angle) based on the springback.

The fact that the load received by the workpiece W (FIG. 6A) has become zero is notified to the robot controller 1 through the sensor control unit 10E for driving and controlling the pressure sensor 2 and the input / output unit 10B (FIG. 1). The

As a result, the robot controller 1 (FIG. 6B) is restarted, and the work gripper 14 having the load of zero is held by the robot gripper 14 that has been waiting at the target angular position (90 °) (104K in FIG. 8). ).

Therefore, as described above, according to the robot controller 1 of the present invention, the workpiece W that has been unloaded and the load has become zero and the bending angle has returned to the target angle of 90 ° (FIG. 6B), Since the robot gripper 14 held at the target angular position (90 °) holds the workpiece, the orientation of the workpiece W and the robot gripper 14 is the same, there is no angle difference between them, and the workpiece W is bent when it is a thin plate. When the workpiece W is a thick plate, the robot gripper 14 is not overloaded.

The present invention eliminates a positioning error between a robot gripper and a workpiece, thereby eliminating the generation of defective products due to workpiece folding, and preventing the robot gripper from being damaged due to overload, and a robot bending method. It is used in the apparatus, and is applicable to not only a descending press brake in which the upper table 20 descends but also an ascending press brake in which the lower table 21 rises during bending.

1 is an overall view of the present invention. It is a figure which shows the robot gripper 14 of this invention. FIG. 6 is an operation diagram (first half) according to the present invention. FIG. 6 is an operation diagram (second half) according to the present invention. FIG. 5 is a detailed explanatory diagram of FIG. 4 (at the time of pressurization). It is a detailed explanatory view (at the time of unloading) of FIG. It is a flowchart for demonstrating the whole operation | movement of this invention. It is a flowchart for demonstrating the operation | movement of the bending process by this invention. It is a subject explanatory drawing of a prior art. FIG. 10 is a detailed explanatory diagram of FIG. 9 (in the case of a thin plate). FIG. 10 is a detailed explanatory diagram of FIG. 9 (in the case of a thick plate). It is explanatory drawing (in the case of a thin plate) of the 1st means for solving a subject. It is explanatory drawing (in the case of a thick board) of the 1st means for solving a subject. It is explanatory drawing (in the case of a thin plate) of the 2nd means for solving a subject. It is explanatory drawing (in the case of a thick board) of the 2nd means for solving a subject.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Robot controller 2 Pressure sensor 3 Stroke sensor 4 Hydraulic pump 5 Servo motor 6 Servo amplifier 7 Hydraulic cylinder 10 NC apparatus 10A CPU
10B I / O unit 10C Storage unit 10D Processing information calculation unit 10E Sensor control unit 10F Back gauge control unit 10G Bending control unit 11 Bending device 13 Robot 14 Gripper 14A Upper gripper 14B Lower gripper 19 Arm 20 Upper table 21 Lower table 23 Projection This D die P punch W work

Claims (4)

In a method of starting a ram composed of an upper table or a lower table and bending a work gripped by a gripper of a robot by cooperation of a punch and a die,
(1) After the ram is activated and the punch comes into contact with the work gripped by the robot gripper, after the work is released from the robot gripper,
(2) The robot gripper is made to follow the movement of the workpiece, and when the robot gripper reaches the target angular position, it stops there and waits.
(3) After that, the ram reaches the limit position and stops, and after the bending process in the process is completed, the ram starts in the opposite direction, and the load of the workpiece becomes zero, and at the same time, the robot waiting at the target angular position A bending method by a robot, wherein a gripper grips a workpiece. The bending method by the robot according to claim 1, wherein in (3), the fact that the load of the workpiece has become zero is detected by a pressure sensor provided in a hydraulic cylinder that is a ram drive source. In the bending apparatus by the robot used directly for carrying out the bending method by the robot according to claim 1,
During bending, the robot gripper is made to follow the workpiece jumping motion with the workpiece released, and waits at the target angle position. After bending, the robot that has the load with zero load waited at the target angle position. A robot bending apparatus having a robot controller to be gripped by a gripper. The robot controller cooperates with the machining information calculation unit, the bending processing control unit, and the sensor control unit,
The machining information calculation unit calculates the trajectory of the robot's work following operation for each process based on the product information,
The bending control unit drives and controls the ram so that the workpiece is bent by the target angle.
4. The sensor control unit drives and controls the pressure sensor so that the pressure sensor detects a load received by the workpiece, or drives and controls the stroke sensor so that the stroke sensor detects a stroke of the ram. Bending device by robot.

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