JPH01159188A - Method of controlling industrial robot - Google Patents

Abstract

PURPOSE: To position a workpiece with the use of a robot so that its two adjacent sides have a specific positional relationship to a predetermined portion of a machine tool with precision by positioning the workpiece while detecting the positions of these two sides that are detected by a plurality of sensors. CONSTITUTION: Depending on the positions of two adjacent sides of a plate W detected by sensors 19A, 19B and 95 arranged on the back and side gauges of a plate hemming machine, an arithmetic part 61 in a controller 21 calculates the distance, direction and route of movement, including turning movement, of a robot hand 45 about a specific point P on the plate W. On the basis of the distance, direction and route of movement, a control part 63 controls the movement of the robot hand 45 roughly on the specific point P on the plate W. A determination part 65 further determines whether one side edge S to be worked of the plate W fulfils a specific positional relationship in which it forms an angle 6 to a hemming line C of a die and also a specific depth (a) at the center point P in relation to the line C on the basis of the detected values by these sensors, and controls the arithmetic part 61 and control part 63 accordingly.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a method of controlling an industrial robot, and more specifically, the present invention relates to a method of controlling an industrial robot, and more particularly, the present invention relates to a method of controlling an industrial robot, and more particularly, the present invention relates to a method of controlling an industrial robot. While gripping the workpiece with a robot hand, at least three sensors capable of position detection are used to control movement so that the two adjacent sides have a specific positional relationship with respect to a predetermined part of the machine tool with high precision. Regarding the control method for placement.

(Prior art) When machining a workpiece using an industrial robot, for example, it may be necessary to position a particular side of a flat part of the workpiece in a particular positional relationship with a predetermined part of a machine tool. There are cases where

For example, there is a process in which a robot holds a four-sided sheet metal with notches at the four corners, and a bending device sequentially bends the four sides of the sheet metal at right angles in the same direction to form a box-shaped product. . At this time, there are cases where the edge of a particular side and the bending line are diagonal. In such a case, the edge must be arranged obliquely at a precise angle and depth with respect to the longitudinal direction of the mold of the folding device.

The robot picks up the sheet metal one by one from the loading location, and first, the robot picks up the recognized gripping points and grips on the sheet metal so that one side of the sheet metal is in a specific positional relationship with respect to the longitudinal direction of the mold of the bending device. It moves while calculating the amount of movement based on the positional relationship between the angle and the placement position on the bending device, and arranges it horizontally.

At this time, if the bending device is of a structure that presses a tapered metal fitting from above the sheet metal and pushes it up with a die from both sides below and bends the sheet metal, the sheet metal will be centered around the bending line during the bending. Both sides of it will lift up. This lick,
The robot must loosen its grip on the sheet metal and move upwards as its grip point rises.

Furthermore, the robot folds the sheet metal one by one, and when it is the turn to bend the edge on the side it is gripping, the robot grips the sheet metal again in order to grip a different side of the sheet metal.

However, when bending each side, the robot temporarily loosens its grip on the sheet metal as the sheet metal is lifted, and then grips it again at the end of the lifting. An error occurs between the actual gripping point and the recognized position inside the robot. Because of this error, when processing other parts of the sheet metal in the next process, such as bending, it becomes impossible to place the sheet metal in the correct position and orientation, resulting in a decrease in processing accuracy, etc. A problem arises.

In such cases, conventionally, the machine tool etc. is provided with a plurality of stopping members, such as a bottle or a stop gauge.
A method has been adopted in which a predetermined portion of the workpiece, which is loosely gripped by a robot hand, is pressed against this member to match the stop member. In this way, the purpose of arranging the straight structural part of the workpiece substantially parallel to a predetermined part of the machine tool was achieved, and the error with the recognized position inside the robot was eliminated.

(Problem to be solved by the invention) However, with this conventional method of aligning the position by pressing against the stop member, although it is possible to roughly align the position, it is impossible to obtain precise dimensions. It is. For example, if you want to keep the machining error within a few tens of microns,
It is clear that the above-mentioned pressing method cannot realize the sole.

In addition, when the workpiece is pressed against the stop member and the surfaces are aligned, the workpiece will move not only in the pressing direction but also in a direction perpendicular to this (left and right), so when the robot grips it again, Problems such as increased errors in this direction also occurred.

Furthermore, when a specific part of the workpiece is placed in a specific positional relationship, such as diagonally, with respect to a predetermined part of the machine tool, the gripping position can be confirmed by pressing it against the stop member as described above. It is impossible to expect to improve machining accuracy with this method. In addition, if the workpiece is only pressed against multiple stop members installed in one direction, if the edge of the workpiece is placed diagonally to the processing area, deviations in the left and right directions perpendicular to the pressing direction will be detected. Can not. Therefore, it is impossible to avoid the risk that the workpiece will shift in the left-right direction while remaining diagonal, resulting in the bending depth of the workpiece being out of order.

This invention was made in view of these conventional problems, and uses a robot to place a specific machining part of a workpiece in a specific positional relationship in the machining section of a machine tool with high precision, and also to eliminate errors caused by repeating the process. It is an object of the present invention to provide a method of controlling an industrial robot that can prevent the increase in the number of robots.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve such an object, in the method for controlling an industrial robot according to the present invention, a substantially planar robot having at least two adjacent sides In an industrial robot, the robot hand grips a workpiece having a part to be machined and arranges the part to be machined at a predetermined part of a machine tool so that the part to be machined is approximately horizontal. A sensor is provided to detect the position of two adjacent sides with respect to the machine tool, and depending on the positions of the two adjacent sides of the workpiece detected by the at least three sensors, the two sides are determined to be a predetermined part of the machine tool. The amount of movement, direction, and path of the robot hand, including rotation, with a specific point on the workpiece as the center of movement, in order to achieve a specific positional relationship with The sensor controls the movement of the robot hand approximately centered on a specific point on the workpiece according to the direction and path, and detects whether or not the two sides are in approximately specific positional relation to the predetermined part. Judging by the detected value of
The method is characterized in that the calculation and control are repeated until a substantially specific positional relationship is achieved.

(Function) With this method of controlling an industrial robot, the machine tool is controlled by sensors installed at at least three locations on the machine tool so that the position of two adjacent sides of the workpiece relative to the machine tool can be detected. It becomes possible to precisely arrange the workpiece while measuring whether two adjacent sides of the workpiece have a specific positional relationship with respect to a predetermined portion of the workpiece. That is, based on the positional information of two adjacent sides of the workpiece detected by at least three sensors relative to a predetermined part of the machine tool, the two adjacent sides have a specific positional relationship with respect to the predetermined part. The amount of movement, direction, and path of the robot hand, including rotation, with a specific point on the workpiece as the center of movement are calculated. The robot hand is then controlled to move according to the determined movement amount, direction, and route. Furthermore, by repeating the calculation and movement control while determining whether or not the two adjacent sides have a specific positional relationship with respect to the predetermined part based on the detection values from a plurality of sensors, the workpiece can be worked more accurately. This allows for more precise machining.

(Example) Hereinafter, an example in which the method for controlling an industrial robot according to the present invention is applied to an actual system will be described in detail based on the drawings.

1 and 2 are block diagrams of an embodiment in which the industrial robot control method of the present invention is applied to a bending robot of a bending system for bending sheet metal, and FIG. 1 is a perspective view of the system. FIG. 2 is a side view as well.

In FIG. 1, the sheet metal bending device 11fl is composed of, for example, a press brake.

A bending robot 3 is mounted on the front side of this sheet metal bending device 1. This bending robot 3 has five movable axes: X, Y, Z, A, and B.

A magazine section 5 containing sheet metal W is provided on the side of the cut sheet metal bending apparatus 1, and a conveyance device 7 for conveying the bent product P to the next process is arranged. Since the configurations of the magazine section 5 and the transport device 7 may be general configurations, a detailed explanation thereof will be omitted.

The sheet metal bending apparatus 1 includes an upper frame 9 and a lower frame 11, similar to a press brake on a boat, and an upper mold 13 is detachably attached to the upper frame 9.

Further, a lower mold 15 is attached to the lower frame 11.

As is well known, a sheet metal bending apparatus 1 having the above configuration is used.
In this method, the sheet metal W interposed between the upper mold 13 and the lower mold 15 is folded by raising and lowering one of the upper and lower frames 9.11 and engaging the upper mold 13 and the lower mold 15. It is used for bending.

Although detailed illustrations are omitted, in this embodiment, the lower frame 11 is configured to move up and down.

Further, the sheet metal bending apparatus 1 is provided with a back gauge 17 that is movable in the front and back direction and positions the sheet metal W in the front and back direction (left and right direction in FIG. 2; Y-axis direction).

At multiple locations on this back gauge 17, sheet metal W
Sensors 19A to 19B and a side sensor 95 for detecting contact between the two are attached. This sensor 19A or B
and 95 are linear transducers, such as direct-acting potentiometers, capable of measuring length and having a relatively long measuring stroke.

With such a configuration, the back gauge 17 and the side gauge 8 are positioned in advance by normal means.
9, the bending robot 3 is placed on two adjacent sides S of the sheet metal W.
When positioning the upper and lower edges of the sheet metal W by detecting whether or not the output of each sensor 19 at a plurality of locations matches a predetermined output value,
It is possible to know whether or not the bending line is parallel to the bending line (hereinafter referred to as bending axis C as necessary), and it is possible to accurately position the sheet metal W.

The output signal from the sensor 19 is input to a robot controller 21 mounted on the upper frame 9. This robot controller 21 is the bending robot 3
, the operation of each operating section in the sheet metal bending apparatus 1, and the operation of the back gauge 17. When the output signals from each sensor 19 are input, the operation of the bending robot 3 is controlled so that the output value of each sensor 19 becomes a desired output value. In this embodiment, the bending robot 3 is attached to a base plate 23 that is integrally attached to the lower frame 11 that can be moved up and down.

More specifically, the base plate 23 extends in the left-right direction (X-axis direction) along the longitudinal direction of the lower mold 15,
A first moving table 25 is supported on the front surface of the base plate 23 so as to be movable in the X-axis direction. This first culm moving table 25
is rotatably provided with a binion (not shown) meshed with a rack rod 27 in the X-axis direction provided on the base plate 23, and is also provided with a first servo motor 29 for rotationally controlling the binion. ing. Note that the power transmission mechanism for rotationally driving the binion by the two first servo motors may have a general configuration, so a detailed explanation thereof will be omitted. The first servo motor 29 is, for example, a stepping motor or the like, and is equipped with a position detection device such as an encoder.

With the above configuration, the first moving table 25 can be moved in the X-axis direction by operating the first servo motor 29, and the center position of the first moving table 25 in the X-axis direction with respect to the reference position can be detected. Can be done.

As is clear from FIGS. 1 and 2, the first movable table 25 is provided with a fan-shaped portion 31 whose upper side is enlarged in the front-rear direction (Y-axis direction), and the upper portion of this fan-shaped portion 31 An arcuate rack member 33 is provided in the housing. A second moving table 35 is supported on the rack member 33 and is movable along the rack member 33 in the Y-axis direction. The second movable table 35 is rotatably provided with a binion (not shown) meshed with the rack member 33, and is also equipped with a second servo motor 37 that rotationally drives the binion. The second servo motor 37, like the first servo motor 29, is equipped with a position detection device such as an encoder.

With the above configuration, by driving the second servo motor 37, the second moving table 35 is moved along the rack member 33 in an arc shape in the Y-axis direction. Y of the second moving table 35
The axial position is detected by a position detection device provided in the second servo motor 37.

As is clear from FIGS. 1 and 2, the second moving table 35 supports three lifting columns that are movable in the up and down Z-axis directions perpendicular to the moving direction of the second moving table 35. ing. A vertical rack is formed on this elevating column 39. A binion (not shown) meshed with this rack is rotatably supported by the second movable table 35, and a third servo motor 41 for rotationally driving this binion is mounted on the second movable table 35. The third servo motor 41, like the first servo motor 29, is equipped with a position detection device.

With the above configuration, the lifting column 39 is moved by the third servo motor 4
1, and the vertical movement position is detected by the position detection device.

An arm 43 extending in the Y-axis direction is appropriately fixed to the upper part of the lifting column 39. At the tip of this arm 43, there is a robot hand 4 that can grip one side edge of the sheet metal W.
5 is installed. More specifically, as shown in FIGS. 1 and 2, the robot hand 45 is provided so as to be rotatable in the vertical direction about an axis that is parallel to the X-axis and is orthogonal to the B-axis. It is provided so that it can freely rotate around the A axis.

A fourth servo motor 47 for vertically rotating the robot hand 45 around the A axis and a fifth servo motor 49 for vertically rotating the robot hand 45 around the B axis are attached to the arm 43. has been done. The fourth and fifth servo motors 47, 49 are equipped with a position detection device like the first servo motor 29 described above.

Note that the robot hand 4 is operated by the fourth servo motor 47.
5 around the A-axis, and a power transmission mechanism for rotating the 5th
The power transmission mechanism a for vertical rotation by the servo motor 49 can have various configurations, and since this configuration is not unique, a detailed explanation thereof will be omitted.

Furthermore, in FIG. 1, an auxiliary gripping device 87 that can temporarily grip the sheet metal W is attached to one side of the lower frame 11 or the base plate 23, and a side gauge 89 is attached via an appropriate bracket. It is installed.

The auxiliary gripping device 87 includes an upper jaw 91 and a lower jaw 93 for gripping the sheet metal W, and can grip the sheet metal W in the same manner as the robot hand 45 by vertically moving the upper jaw 91.

The side gauge 89 is used to detect the positional relationship between the bending robot 3 and one side edge of the sheet metal W held by the robot hand 45, and includes a side sensor 95. This side sensor 95, like the sensor 19 provided in the back gauge 17, is composed of a linear transducer such as a direct-acting potentiometer. The output value of this side sensor 95 is input to the robot controller 21.

Therefore, when one side edge of the sheet metal W held by the robot hand 45 comes into contact with the opening sensor 95 and the output value of this side sensor 95 is a predetermined output value, the bending robot 3 is moved in the X-axis direction. The position detected by the position detection device provided in the first servo motor 29 is detected by the robot controller 2.
It is detected by reading it into 1. By comparing the position detection value of the reference position when the sheet metal W is not gripped, the positional relationship in the X-axis direction between one side edge of the sheet metal W gripped by the robot hand 45 and the bending robot 3 is determined. You can know. Therefore, the sheet metal W can be accurately positioned in the X-axis direction with respect to the mold 13.15 using the side gauge device 89 as a reference.

FIG. 3 is an explanatory diagram of the main internal configuration of the robot controller 21 and the position correction operation of the sheet metal W of the bending robot 3 in the above-described one embodiment system.

When arranging the sheet metal W so that one end edge S and the adjacent side T of the linear structural part have a specific positional relationship with respect to the bending axis C, which is the bending line formed by the upper and lower molds 13 and 15, the back gauge Input the detected values of the contact position of the sheet metal W from the plurality of sensors 19A to 19B attached to the side gauge 17 and the side sensor 95 attached to the side gauge 89,
Multiple A/D converters to digital values 51 A to 5
1B and 53 are provided inside the robot controller 21.

And, these plural A/Ds 51A to 51B,
Detected values from the plurality of sensors 19A to 19B and the side sensor 95, which are converted into digital values by
There is an arithmetic unit 61 that calculates the movement amount, direction, and route of the robot hand 45, including rotation, with the movement center being .

In addition, the robot hand 45 calculated by the calculation unit 61
A specific point (
For example, there is a movement control unit 63 that controls the movement of the robot hand 45 approximately centered on point P). This movement control section 63
There are servo amplifiers 71 to 79 for each axis, which drive the servo motors 29, 37, 41, 47, and 49 for each axis of the bending robot 3 according to control by the servo amplifiers 71 to 79 for each axis.

Furthermore, the sheet metal W
The edge S to be processed has a specific positional relationship with respect to the bending axis C,
For example, a determination control unit that determines whether or not a positional relationship such as a certain depth a is satisfied at the center point P while forming a certain angle θ, and controls the calculation unit 61, movement control unit 63, etc. according to this determination. 65 are provided.

Further, there is a storage unit 67 that stores various information such as the shape of the sheet metal W to be processed, the part to be processed, and the currently recognized gripping point.

Next, the operation of this embodiment system will be explained.

4 and 5 show sheet metal bending processing device 1 for sheet metal W.
13 is a flowchart of positioning control when placing the mold between the upper and lower molds 13 and 15.

The robot hand 45 of the bending robot 3 starts an operation of gripping a sheet metal W, which is a workpiece to be processed, and placing one end edge S of the sheet metal W between the upper and lower molds 13 and 15 (step 101 in FIG. 4).

First, from the grip point information of the sheet metal W held in the storage unit 67 and the information such as the position and angle at which the sheet metal W should be placed, one end edge S of the sheet metal W is moved slightly in front of the approximate placement position. The edge T adjacent to the edge S is the side gauge 8
Move the sensor 19 so that it is slightly in front of the side sensor 95 attached to the
A to B and the side sensor 95 are brought into contact with each other (step 103).

Next, the position of the sheet metal W is corrected while detecting input values from at least two sensors 19A to 19B and the side sensor 95 (step 105).

Details of the position correction process for the sheet metal W are shown in FIG.

When the sheet metal position correction process starts (step 20 in Figure 5)
1) First, input the detection values from the plurality of sensors 19A to 19B and the side sensor 95 (step 20).
3>.

Then, the absolute value of the difference (error) between the positional information held in the storage unit 67 at which the sheet metal W should be placed and the input values from the plurality of sensors 19A to B and the side sensor 95 is determined (in the same step 205).

Next, the determination control unit 65 compares the absolute value of this error with the value of the tolerance range held in the storage unit 67 (step 7).
207).

As a result of this comparison, if the error is outside the allowable range (No in step 207), the calculation unit 61
In step 209, the movement amount, direction, and path of the robot hand 45, including rotation, are calculated with a specific point of the sheet metal W, for example, the midpoint P of one edge S of the sheet metal W, as the center of movement (step 209).
).

To explain in more detail, in FIG. 3, the sheet metal W is
For example, if the bending axis C is not at a predetermined angle and depth as shown by the two-dot chain line, the plurality of sensors 1
At least one of the sensors 9A to 9B and the side sensor 95 exceeds the allowable range value stored in the storage section 67. If the current degree of contact with the sensor 95 is extremely small and the difference between the input value from the sensor 95 and the standard position information held in the storage unit 67 is larger than the above-mentioned allowable range, the calculation unit 61 Grasping robot hand 4
5 in the X-axis direction is calculated.

Further, if the degree of contact with the sensor 19A is extremely small and the difference between the input value from the sensor 19A and the standard position information held in the storage unit 67 is larger than the above-mentioned allowable range, the calculation unit 61 The amount of movement of the robot hand 45 that grips the sheet metal W with a specific point P as the center of movement is calculated. That is, the amount of movement is calculated by adding up the rotation angle of the robot hand 45 that grips the sheet metal W with the point P as the center point, and the amount of forward movement of the robot hand 45 determined from the current values of both sensors 19A and 19B. Then, the amount of movement and direction of each axis of the bending robot 3 necessary to achieve this amount of movement are calculated. In the example shown by the two-dot chain line in Figure 3, the related axes are the A-axis (rotation), the X-axis (rightward movement), and the Y-axis (reciprocating movement). The movement path is also considered so that the sheet metal W and each part of the bending robot 3 do not come into contact with any part of the sheet metal bending device 1, etc. For this reason, the remaining axes of the bending robot 3; There may also be cases where movement in the Z axis is also required.

According to the movement amount, direction, and path calculated in this way, the movement control unit 63 operates the servo amplifiers 71 to 79 for each axis of the robot to be moved, and drives the servo motor for that axis (step 211 in FIG. 5). ).

In this way, when one movement of the robot hand 45 holding the sheet metal W is completed, the process returns to inputting the detected values of the sensors 19A to 19B and the side sensor 95 (step 2 of the same step).
03).

On the other hand, if the difference between the input value of Senna and its standard value is within the allowable range (Yes at step 207), this state is maintained one more time (for example, four times) in a row. (step 213),
This is to determine whether the detected values of the above-mentioned sensors 19A to B and the side sensor 95 are not temporary, but are stably detected, that is, whether or not a value within the allowable range is momentarily detected by chance. This is a process to ensure that the sheet metal W is not placed in the wrong place and realize accurate placement of the sheet metal W.

Of course, this processing is incidental and not essential to the control method according to the present invention.

If a value within the above tolerance range is detected, then 1
If the times are not consecutive (No in step 213), the process returns to inputting the detection values of the sensors 19A and 19B (step 2
03>.

If the above state is detected once in a row (Yes in step 213), this sheet metal position correction process ends (step 215).

Returning to FIG. 4, when the sheet metal position correction process is completed, the bending table, that is, the lower frame 1 of the sheet metal bending processing apparatus 1
Raise the lower mold 15, which is the lower mold attached to 1, and
A command to sandwich the sheet metal W between the upper mold 13 mounted on the upper frame 9 is issued from the determination control section 65 to the sheet metal bending apparatus 1 (step 107 in FIG. 4).

Then, it is determined whether the sheet metal W is perfectly sandwiched between the upper and lower molds 13 and 15 and the state immediately before bending of the sheet metal W actually starts, that is, whether or not the binch point has been reached. Step 109).

If the binching' point has not yet been reached (No in step 109), the sheet metal position correction process is performed again (step 111). This is done on the assumption that it will be pushed up and its position will shift. however,
In the sheet metal position correction processing at this time, the above-mentioned one-time check to see if it is within the continuous allowable range (step 213 in FIG. 5) is omitted.

After the sheet metal position correction processing has been carried out, check whether the pinching point has been reached again (step 1 in Figure 4).
Return to 09).

If the binching point is reached (Yes in step 109), the sheet metal positioning process ends (step 113).
, the bending process of the sheet metal W is started (step 115 of the same).
), at this time, the robot hand 45 loosens its grip on the sheet metal W in preparation for lifting the grip position of the sheet metal W due to bending.

In this way, the bending process of the sheet metal W of the workpiece to be processed is executed, and when the bending is completed, the robot hand 45
At this time, even if an error occurs between the recognized position held in the storage unit 67 of the gripping point of the sheet metal W by the robot hand 45 and the actual gripping point after regripping, the next processing At this time, the above-described position correction processing and the like are executed again, so the precision with respect to the machining position does not deteriorate.

In this way, when the robot hand 45 grips the sheet metal W and bends each side of the sheet metal W, first, one side edge of the sheet metal W is brought into contact with the side sensor 95 provided in the side gauge 89. At least, the positional relationship between one side edge of the sheet metal W and the bending robot 3 in the X-axis direction is detected.

The positioning in the X-axis direction is performed using the side gauge 89 as a reference, and the positioning of the sheet metal W in the Y-axis direction is performed by positioning the back gauge 17 in advance, and using a plurality of sensors 19 provided on the back gauge 17 to determine the position of the sheet metal W in the Y-axis direction. This is done by moving the bending robot 3 in the Y-axis direction and appropriately rotating the robot hand 45 around the A-axis so that the detection values of each sensor 19 become the desired detection values.

That is, the bending process is performed after the sheet metal W is accurately positioned in the X-axis direction and the Y-axis direction.

In this way, while holding the sheet metal W with the robot hand 45, it is possible to bend each side of the sheet metal W with high precision.

Then, the sheet metal W after the bending process is transferred to the position of the transport device 7 by the bending robot 3, and then,
The product P is transported to the next process by the transport device 7.

The application of the industrial robot control method of this invention is as follows:
The present invention is not limited to the configuration of the embodiment system described above, and can of course be implemented in various forms by making appropriate changes.

For example, the plurality of sensors that detect the position of a specific part of the workpiece are not limited to the potentiometers described above,
It is also possible to use a device that detects the position using a laser beam and a photosensor, a non-contact sensor such as a CCD camera, etc.

In addition, the arrangement method and number of sensors are as follows: one on the side,
Further, it is not limited to arranging two or three pieces in the same straight line in front, but it is possible to select an appropriate number and arrangement according to the shape of the workpiece and the processing method.

[Effects of the Invention] As described above in detail, the method for controlling an industrial robot according to the present invention enables the positioning of a workpiece to be processed while detecting the positions of two adjacent sides of the workpiece using a plurality of sensors. , it becomes possible for the robot to place the workpiece so that these two sides have a specific positional relationship with respect to a predetermined part of the machine tool with high precision. In addition, even if the workpiece is repeatedly gripped by the robot hand depending on the machining process, the position can be corrected using the sensor, so the gripping point is unlikely to be misaligned and can always be positioned accurately. become.

[Brief explanation of the drawing]

1 and 2 are configuration diagrams of a bending system according to an embodiment of the present invention, with FIG. 1 being a perspective view, and FIG.
The figure is a side view. Further, FIG. 3 is a diagram showing the gripping state of the workpiece and the internal configuration of the robot controller in the same embodiment, and FIGS. 4 and 5 are operation flowcharts in the same embodiment. 1... Sheet metal bending processing device 3... Bending robot 19. 19A, 19B... Sensor 45...
・Robot hand 51A, 51B, 53...A/D
61... Arithmetic unit 63... Movement control unit 65...
Judgment control unit 67...Storage unit 95...Side sensor agent Patent attorney Yasuo Miyoshi 2nd Figure 5

Claims (1)

[Claims] (1) In an industrial robot that uses a robot hand to grip a workpiece having a substantially planar workpiece having at least two adjacent sides and arranges the workpiece at a predetermined part of a machine tool so that the workpiece is approximately horizontal, Sensors for detecting the positions of two adjacent sides of the work with respect to the machine tool are provided at at least three locations on the machine tool, and the positions of the two adjacent sides of the work detected by the at least three sensors are Then, calculate the amount of movement, direction, and path of the robot hand, including rotation, with a specific point on the workpiece as the center of movement so that these two sides have a specific positional relationship with the predetermined part of the machine tool. , In accordance with the movement amount, direction, and path of the robot hand determined by this calculation, the movement of the robot hand approximately centered on a specific point on the workpiece is controlled, and the two sides are approximately specified relative to the predetermined portion. A method for controlling an industrial robot, characterized in that it is determined based on the detected value of the sensor whether or not a positional relationship has been reached, and the calculation and control are repeated until a substantially specific positional relationship is achieved.