JP2013173196A - Position correcting method of robot handling arm - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position correcting method of a robot handling arm easy in teaching.SOLUTION: A position correcting method of a robot handling arm 7a comprises: a first step for detecting a work W sent by a conveyor 1 by a sensor 2; a second step for stopping the work W in the vicinity of a target position P1; a third step for photographing the work W by a CCD camera 4 fixed to the upper part of the target position P1 on the basis of a detection signal detected in the first step; a fourth step for processing image data of a photographed image by an image processing part and calculating a stop position of the work W; and a fifth step for attracting and holding the work W in a position in which the handling arm 7a is corrected on the basis of calculated stop position data. The stop position data are calculated from position coordinates of edges of at least two points of the work W with respect to an arbitrary camera original point.

Description

  The present invention relates to a position correcting method for a handling arm of a robot, and more particularly to a position correcting method for a handling arm of a robot that is easy to teach the robot and is excellent in transfer efficiency.

In press working, a robot is generally used, and workpieces are sequentially and continuously conveyed by the robot.
Here, a teaching operation is performed on the robot before the main processing, and based on this, the robot carries the workpiece at the target position.

  By the way, for example, when the workpiece is arranged at a position shifted from the target position, the robot sucks and holds the workpiece at the shifted position and transports it as it is. That is, the pickup accuracy is deteriorated. As a result, the quality of the press-processed product may be deteriorated, or in some cases, the die of the press device may be damaged.

On the other hand, a method for positioning a workpiece at an accurate target position has been studied. For example, a configuration in which a workpiece is positioned by a plurality of centering devices positioned immediately downstream of the carry-out conveyor, and the workpiece positioned by the plurality of centering devices is picked up by a plurality of loading robots and loaded on a pallet for each of a plurality of press cycles. A workpiece loading device is known (see Patent Document 1 or 2).
As described above, the positioning of the workpiece can be accurately performed by using the centering device.

  However, when the workpiece is positioned using the centering device, the centering device is brought into contact with the side surface of the workpiece, so that the workpiece is damaged. In particular, when the workpiece is thin and relatively soft, the workpiece is easily damaged. In other words, in this case, even if a workpiece at an accurate position is conveyed by the robot, the quality is poor as a result.

  In such a situation, when teaching the target position set on the workpiece with respect to the robot, the target mark provided on the basis of the target position is imaged by the imaging unit, and the captured target mark and imaging unit are captured. A recognition step for recognizing the relative positional deviation between the robot hand and the target position from the reference position of the imaging range, and controlling the robot joint drive so as to reduce the recognized positional deviation. There is known a position correction method including a first position correction step for correcting (see, for example, Patent Document 3).

JP 2003-205331 A JP 2003-205332 A JP 2010-188432 A

However, teaching and control in the position correction method described in Patent Document 3 requires that the operator teach the robot the target position during work of the robot hand, particularly during the work of the robot and camera. It is necessary to match the target positions. In addition, the operator needs to manually drive the joints of the robot. All of these operations are extremely difficult, and have the disadvantage that skill is required for the operations.
Moreover, since teaching and control take time and the robot apparatus is stopped for a long time, there is a disadvantage that the conveyance efficiency is deteriorated.

  The present invention has been made in view of the above circumstances, and provides a position correction method for a handling arm of a robot that is easy to teach, can suck and hold a workpiece at a position corrected, and has excellent transport efficiency. With the goal.

  The inventors of the present invention have intensively studied to solve the above-mentioned problems. As a result, the work is stopped in the vicinity of the target position, the CCD camera is fixed above the target position, and the work photographed by the CCD camera is used. An accurate position of the workpiece is calculated from the image, and based on the stop position data, it is found that the above problem can be solved by correcting the position where the handling arm sucks and holds the workpiece, and the present invention is completed. It came to.

  The present invention is (1) a position correcting method for a handling arm of a robot when attracting and holding a work, and includes a first step of detecting a work sent by a conveyor by a sensor, and stopping the work in the vicinity of a target position. Based on the detection signal detected in the second step, the third step of photographing the workpiece with a CCD camera fixed above the target position, and image data of the photographed image in the image processing unit The fourth step of processing and calculating the stop position of the workpiece, and the fifth step of attracting and holding the workpiece at the position where the handling arm is corrected based on the calculated stop position data. A robot handling arm calculated from the position coordinates of at least two edge portions of the workpiece with respect to an arbitrary camera origin It resides in the position correction method.

  The present invention resides in (2) the position correcting method of the handling arm of the robot according to (1), wherein the handling arm is horizontally movable and rotatable.

  According to the present invention, (3) a magnet is provided in the moving direction of the conveyor, and the magnet stops the workpiece near the target position by a magnetic force based on the detection signal. It exists in the position correction method of the handling arm of a robot.

  This invention exists in the position correction method of the handling arm of the robot as described in any one of said (1)-(3) whose edge part is a corner | angular part of a workpiece | work.

  The present invention includes (5) a setting step for arbitrarily setting a target position before the first step, and a teaching step for teaching the operation to the handling arm so as to attract and hold the workpiece at the target position. (1) It exists in the position correction method of the handling arm of the robot as described in any one of (4).

In the robot arm handling position correction method according to the present invention, the work is stopped in the vicinity of the target position, the work is photographed by the CCD camera, the work position deviation is calculated, and the handling is performed based on the stop position data. By correcting the position where the arm sucks and holds the workpiece, the workpiece can be sucked and held at the corrected position (hereinafter also referred to as “correction position”).
Thereby, the picking-up accuracy of a workpiece | work is excellent, generation | occurrence | production of the quality defect of a press work product is prevented, and conveyance efficiency improves.

At this time, in the method for correcting the position of the handling arm of the robot according to the present invention, since the sensor is used, the work can be photographed with the CCD camera at the timing.
In addition, since the position deviation of the workpiece is calculated from the position coordinates of at least two edge portions (preferably corner portions) of the photographed workpiece with respect to an arbitrary camera origin, the measurement error becomes extremely small and the accuracy is high. Stop position data is obtained.

  In the robot handling arm position correcting method according to the present invention, when a magnet is provided in the moving direction of the conveyor, the work is surely stopped near the target position where the CCD camera is fixed upward by the magnetic force of the magnet. Can be made.

  In the method for correcting the position of the handling arm of the robot according to the present invention, the CCD camera is fixed and the workpiece is stopped in the vicinity of the target position using the sensor. There is no need to match the position. That is, teaching is made very easy because it is only necessary to teach the target position at the time of working of the handling arm to the robot. The target position can be arbitrarily determined.

  In the method for correcting the position of the handling arm of the robot according to the present invention, when the handling arm is horizontally movable and rotatable, the movement to the correction position is smooth, and the workpiece can be reliably sucked and held at the correction position. It becomes possible.

FIG. 1 is a schematic diagram showing a transport apparatus in which the method for correcting the position of the handling arm of the robot according to the present embodiment is used. FIG. 2 is a flowchart for explaining a position correction method for the handling arm of the robot according to the present embodiment. FIG. 3 is a flowchart for explaining control in the position correcting method for the handling arm of the robot according to the present embodiment. FIG. 4 is a schematic diagram for explaining a method of calculating stop position data of a work stop position from image data in the position correcting method of the handling arm of the robot according to the present embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

FIG. 1 is a schematic diagram showing a transport apparatus in which the method for correcting the position of the handling arm of the robot according to the present embodiment is used.
As shown in FIG. 1, a transfer device 10 that uses a method for correcting the position of a handling arm of a robot is provided in a conveyor 1, a sensor 2 that detects a workpiece W sent by the conveyor 1, and a moving direction of the conveyor 1. A magnet 3 for stopping the workpiece W, a CCD camera 4 fixed above the magnet 3, a robot 7 for attracting and holding the workpiece W stopped by the magnet 3 by a handling arm 7a, and a conveyed workpiece W The stack 5 is mounted.

According to the said conveying apparatus 10, the handling arm 7a can adsorb | suck hold | maintain and convey the workpiece | work sent by the conveyor 1. FIG.
For example, a stack 5 in which a plurality of sheets are stacked with high accuracy can be obtained by using the transfer device 10 after a shearing process for cutting a single work or a cleaning process for cleaning each work.

Next, a method for correcting the position of the handling arm 7a when the workpiece W is attracted and held using the transfer device 10 will be described.
FIG. 2 is a flowchart for explaining a position correction method for the handling arm of the robot according to the present embodiment.
As shown in FIGS. 1 and 2, in the robot arm handling position correction method according to the present embodiment, a setting step SA for arbitrarily setting a target position P1 and a work W being sucked and held at the target position P1. Teaching step SB for teaching the operation to the handling arm 7a, a first step S1 for detecting the workpiece W sent by the conveyor 1 with the sensor 2, a second step S2 for stopping the workpiece W in the vicinity of the target position P1, Based on the detection signal detected in the first step S1, a third step S3 for photographing the workpiece W by the CCD camera 4 fixed upward at a certain distance from the target position P1, and image data of the photographed image are obtained. Based on the fourth step S4, which is processed by the image processing unit and calculates the stop position of the workpiece W, and the calculated stop position data A fifth step S5 for sucking and holding the workpiece W at a position handling arm 7a is corrected consists.

Hereinafter, each step will be described in more detail.
(Setting step)
The setting step SA is a step for arbitrarily setting the target position P1 on the conveyor 1.

The target position P1 is a target position for stopping the workpiece W on the conveyor 1, and is a target position for the robot 7 to take out the workpiece W.
In the position correction method for the handling arm 7a of the robot, the sensor 2, the magnet 3, the CCD camera 4, and the robot 7 described later are positioned with reference to the target position P1.

(Teaching step)
The teaching step SB is a step of teaching the handling arm 7a to attract and hold the workpiece W at the target position P1. That is, it is a step of moving the handling arm 7a of the robot 7 toward the target position P1 and storing the position. Incidentally, when the handling arm 7a is operated in this state, the handling arm 7a sucks and holds the workpiece stopped at the target position P1, and transports it.

  Here, as described above, the target position P1 is arbitrarily determined. For this reason, for example, the position where the handling arm 7a sucks and holds the workpiece W on the conveyor 1 may be set as the target position P1. In this way, if the position where the handling arm 7a holds the workpiece W by suction is set as the target position P1, the teaching of the operation of the handling arm 7a becomes extremely easy.

(First step)
The first step S <b> 1 is a step in which the sensor 2 detects a workpiece W that is sent at an arbitrary speed by the conveyor 1.
Here, the sensor 2 is not particularly limited, and for example, a proximity sensor, a photoelectric sensor, or the like is appropriately used.

FIG. 3 is a flowchart for explaining control in the position correcting method for the handling arm of the robot according to the present embodiment.
As shown in FIG. 3, in the method for correcting the position of the handling arm of the robot according to the present embodiment, when the sensor 2 detects the workpiece W, the detection signal is transmitted to the sequencer 20.

(Second step)
The second step S2 is a step for stopping the workpiece W in the vicinity of the target position P1. In the method for correcting the position of the handling arm of the robot according to the present embodiment, the magnet 3 provided in the moving direction of the conveyor 1 is used as means for stopping the workpiece W.

  In the second step S2, the work W is sent by the conveyor 1, and the work W is stopped at the position of the magnet 3 provided on the work W by the magnetizing force of the magnet. At this time, the stop position where the workpiece W is stopped may be a position shifted from the target position P1. The ON / OFF of the magnet 3 corresponds to the ON / OFF of the conveyor.

(Third step)
The third step S3 is a step of photographing the workpiece W stopped at the stop position by the CCD camera 4 fixed above the target position P1, based on the detection signal detected by the sensor 2.

  In the third step S <b> 3, when receiving the detection signal from the sensor 2, the sequencer 20 transmits a command signal for causing the CCD camera 4 to photograph the workpiece W. Note that the timing at which the sequencer 20 transmits the command signal after receiving the detection signal from the sensor 2 can be freely set by the user. Thereby, according to the length of the conveyor 1, the speed of the workpiece | work W sent by the conveyor 1, etc., the workpiece | work W can be image | photographed with timing.

  When the CCD camera 4 receives a command signal at a predetermined timing, the CCD camera 4 captures the workpiece W. At this time, the entire area of the workpiece W may not be included in the area where the CCD camera 4 can shoot (hereinafter referred to as “shooting area”). That is, as will be described later, at least a part of the work W may be in the imaging region. Thereby, the freedom degree of the stop position of the workpiece | work W spreads.

  In the position correction method for the handling arm 7a of the robot according to the present embodiment, the work W is stopped at the stop position near the target position P1 using the sensor 2, and at least a part of the work W (for example, the work W Since it is sufficient if the edge of W is in the imaging region, teaching to match the target at the time of shooting by the CCD camera 4 with the target position P1 becomes unnecessary.

(4th step)
The fourth step S4 is a step of processing the image data of the photographed image by the image processing unit 21 of the computer and calculating the stop position data of the work stop position W.

  The stop position data is calculated from position coordinates of at least two edge portions of the workpiece W in the image data with respect to an arbitrary camera origin in a predetermined vision pattern. Although the edge can be arbitrarily determined, the edge is preferably a corner of the workpiece W. In this case, since the measurement error becomes extremely small, more accurate stop position data can be obtained.

Here, a method of calculating stop position data by a computer using the work W1 at the target position P1 and the work W2 stopped at the stop position P2 will be described.
FIG. 4 is a schematic diagram for explaining a method of calculating stop position data of a work stop position from image data in the position correcting method of the handling arm of the robot according to the present embodiment.
As shown in FIG. 4, the work W2 stopped at the stop position P2 is a position where the work W1 at the target position P1 is tilted to be a virtual work W3, and the virtual work W3 is slid in parallel.

First, arbitrary robot coordinates calculated from the target position at the time of the operation of the robot handling arm are registered in the computer as the camera origin.
When the coordinates of the camera origin are (0, 0), the inclination θ of the work W2 at the stop position P2 is calculated with respect to the work W1 at the target position P1.
The inclination θ is defined by the coordinates (0, 0) of the lower left corner K1 and the coordinates (x1, y1) of the lower right corner K2 of the workpiece W1 at the target position P1, and the coordinates (0, 0) of the lower left corner K1 of the virtual workpiece W3. 0) and the coordinates (x2, y2) of the lower right corner K2.
Then, the positions are the coordinates (xa, ya) and the coordinates (x3, y3) of the lower left corner K1 and the coordinates (0, 0) of the lower left corner K1 of the virtual workpiece W3 (0). , 0) and the coordinates (x2, y2) of the lower right corner K2.
As a result, stop position data in the x-axis direction, the y-axis direction, and the inclination θ is obtained. Although the coordinates of the camera origin are (0, 0), they may be at different positions. In this case, the coordinate value of the camera origin may be simply added or subtracted from all values.

(5th step)
The fifth step S5 is a step in which the robot control panel 27 receives the calculated stop position data, and holds and holds the work W at the position where the handling arm 7a is corrected based on the stop position data.

  In the position correction method for the handling arm 7a of the robot according to the present embodiment, the handling arm 7a is horizontally movable and rotatable. Accordingly, the handling arm 7a can be horizontally moved and rotated in accordance with the stop position data of the x-axis direction, the y-axis direction, and the inclination θ described above, and the movement to the correction position becomes smooth. In addition, the work W can be reliably sucked and held at the correction position.

  In this way, the workpiece W held by suction is conveyed by the robot 7 and can be made into a stack 5 in which, for example, a plurality of sheets are stacked with high accuracy. Note that the position correction method for the handling arm 7a of the robot according to the present embodiment is continuously performed for each workpiece W.

  According to the position correction method for the handling arm 7a of the robot according to the present embodiment, the above-described operations are repeated, so that the workpiece pick-up accuracy is improved, the quality of the pressed product is prevented from being generated, and the transfer efficiency Will also improve.

  As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to embodiment mentioned above.

  In the position correction method for the handling arm 7a of the robot according to the present embodiment, the shape of the workpiece W is shown as a rectangular shape in FIG. 4, but is not limited thereto.

  In the method for correcting the position of the handling arm 7a of the robot according to the present embodiment, the magnet 3 provided in the moving direction of the conveyor 1 is used as means for stopping the workpiece W. However, the present invention is not limited to this. It may be air adsorption or the like.

  In the position correction method for the handling arm 7a of the robot according to the present embodiment, the handling arm 7a is horizontally movable and rotatable, but the present invention is not limited to this.

  In the position correction method for the handling arm 7a of the robot according to the present embodiment, the stop position data is calculated from the position coordinates of at least two corners of the workpiece W. However, if the position coordinates can be set, It is not limited to the department. For example, the edge part which is not a corner | angular part, the hole-shaped part in a workpiece | work, etc. may be sufficient.

In the method for correcting the position of the handling arm of the robot according to the present embodiment, in the second step S2, the workpiece W is stopped near the target position P1 regardless of the detection signal from the sensor 2, but the sensor 2 The workpiece W may be stopped in the vicinity of the target position P1 via the sequencer 20 based on the detection signal from.
In this case, the workpiece W can be stopped in the vicinity of the target position P1 at a timing in accordance with the length of the conveyor 1, the speed of the workpiece W sent by the conveyor 1, and the like.

  The robot handling arm position correcting method of the present invention is used in the field of press working. In particular, it is suitable when it is desired to transport the workpiece W with high pickup accuracy. According to the position correcting method of the handling arm of the robot of the present invention, teaching is easy, the workpiece can be sucked and held at the position corrected position, and the conveyance efficiency is excellent.

DESCRIPTION OF SYMBOLS 1 ... Conveyor 2 ... Sensor 3 ... Magnet 4 ... CCD camera 5 ... Stack 7 ... Robot 7a ... Handling arm 10 ... Conveying device 20 ... Sequencer 21. ..Image processor 27 ... Robot control panel K1 ... Lower left corner K2 ... Lower right corner P1 ... Target position P2 ... Stop position S1 ... First step S2 ... First 2 steps S3 ... 3rd step S4 ... 4th step S5 ... 5th step SA ... Setting step SB ... Teaching step W, W1, W2, W3 ... Workpiece

Claims (5)

A method for correcting the position of a handling arm of a robot when attracting and holding a workpiece,
A first step of detecting a workpiece sent by a conveyor with a sensor;
A second step of stopping the workpiece in the vicinity of the target position;
A third step of photographing the workpiece with a CCD camera fixed above the target position based on the detection signal detected in the first step;
A fourth step of processing the image data of the photographed image by the image processing unit and calculating a work stop position;
And a fifth step of attracting and holding the workpiece at a position where the handling arm is corrected based on the calculated stop position data,
A method for correcting a position of a handling arm of a robot, wherein the stop position data is calculated from position coordinates of at least two edge portions of the workpiece with respect to an arbitrary camera origin.   2. The method of correcting a position of a handling arm of a robot according to claim 1, wherein the handling arm is horizontally movable and rotatable.   The position of the handling arm of the robot according to claim 1 or 2, wherein a magnet is provided in a moving direction of the conveyor, and the magnet stops the workpiece near a target position by a magnetic force based on the detection signal. Correction method.   The position correcting method for the handling arm of the robot according to claim 1, wherein the edge is a corner of the workpiece. Before the first step,
A setting step for arbitrarily setting the target position;
Teaching step of teaching the handling arm to attract and hold the workpiece at the target position;
The position correction method of the handling arm of the robot of any one of Claims 1-4 provided with these.

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