JPH02218578A - Transfer device for work - Google Patents

Abstract

PURPOSE:To easily correct the direction of a work in a constant direction by providing a means for detecting the work shape by the detecting means provided on the way of the transfer passage by which the work is transferred and correcting the direction of the work so that the work direction becomes a constant direction based on this detected signal. CONSTITUTION:In passing the transfer passage where the work 2 subjected to chucking by a robot hand 17 is transferred, a signal corresponding to the feature of the work shape is obtained from a detecting member 1B. Then, based on this detection signal a robot hand 17 having chucked the work is turned by a correction means 21C, the direction of the work 2 is corrected in a constant direction and the work 2 is placed at a specific transfer place.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a workpiece transfer device, and particularly to a device for correcting the orientation of a workpiece in a constant direction when a workpiece with a complicated shape is transferred to the next process by a robot. The present invention relates to the configured work transfer device.

Conventional technology For example, in a workpiece transfer device that transfers a workpiece placed on a box-shaped pallet to a conveyor for the next process by the operation of an industrial robot, the robot hand chucks the workpiece and takes it out from the pallet. , the workpiece is placed on the conveyor in a fixed direction. In particular, 'l! of the shape produced by casting! In the process of feeding rough workpieces to machine tools using a conveyor, the direction in which the workpieces are placed on the pallet may not be constant. In this case, the orientation of the workpieces chucked by the robot hand is corrected to a constant direction. There is a need. If the workpiece has a shape that can be gripped from the outside, the image processing device recognizes the workpiece placement direction, rotates the robot hand to match the workpiece placement direction, and then chucks the workpiece. Therefore, by rotating the robot hand at a predetermined angle during the process of transferring the work, the rework can be directed in a fixed direction.

However, as a method for recognizing the workpiece placement direction,
A common method is to perform this based on data obtained by imaging with a carrier camera of an image processing device. The direction in which the workpiece is placed is identified. However, in the case of a workpiece whose outer periphery cannot be grasped as described above, it has been considered to chuck the workpiece by inserting a chuck claw of a robot hand into a hole drilled in the workpiece, for example.

In this case, when recognizing the workpiece placement direction, the image processing device detects the center points of two holes drilled in the workpiece, and calculates the difference between the center line connecting these two points and the J1 quasi-angle. The workpiece placement direction will be recognized by calculation.

Problems to be Solved by the Invention However, in the case of the above-described method of identifying the workpiece placement direction from holes drilled in the workpiece, a wide-angle lens is generally used because the m-image camera conveys an image on the plane of the entire pallet. Since each workpiece is imaged relatively small, it is difficult to find holes, which are characteristic of the workpiece.

As a method to solve the above problem, in addition to the image carrying camera that carries the entire pallet and detects the workpiece position, it is possible to detect only the workpieces to be chucked by the robot hand.
It is also conceivable to provide a separate II image camera. In this method, for example, when the shape of the workpiece is complex and there are height differences, problems arise in that it is difficult to focus and recognize two holes drilled in the workpiece as feature points.

Therefore, an object of the present invention is to provide a work transfer device that solves the above problems.

Means for Solving the Problems The present invention provides the above-mentioned workpiece transfer device with a detection means for detecting the shape of the workpiece by passing the workpiece in the middle of the transfer path where the workpiece is transferred by the operation of the robot. A workpiece direction correction means is provided for correcting the direction of the workpiece by rotating the robot hand based on the obtained signal so that the direction of the workpiece in the next stroke is in a fixed direction.

When the workpiece chucked by the robot hand passes through the transfer path, the detection member receives a signal corresponding to the characteristics of the workpiece shape, and the robot hand that has chucked the workpiece is detected based on this detection signal. The workpiece is rotated to correct the orientation of the workpiece in a certain direction and place the workpiece at a predetermined transfer location.

Embodiment FIGS. 1 and 2 show an embodiment of the work transfer device according to the present invention.

In both figures, the work transfer device 1 is approximately an industrial robot 1A.
, a workpiece direction detection device (detection means) 1B that detects the direction of the workpiece 2 taken out by the industrial robot 1A, and a control device 21 that controls the operation of the industrial robot 1A.

The industrial robot 1A is connected between a conveyor 4 to which a box-shaped pallet 3 on which a workpiece 2 is placed is supplied, and a conveyor 5 for the next process to supply the workpiece 2 to a machine tool (not shown). The workpieces 2 on the pallet 3 are taken out one by one and transferred to the conveyor 5. The industrial robot 1 has a cylindrical coordinate system [1 pot, a base 7 fixed to the floor 6;
A turning table 8 is provided so as to be rotatable in the direction of the arrow claw at the top.
and a pair of guide members 9a standing up on the turning table 8.
, 9b, and an arm 11 that is extendable and retractable.

A ball screw mechanism (not shown) is provided in the arm body 10 to be screwed into a male screw 12 on the rotation table 8, and an actuator 14 supported by a column 13 drives the male screw 12 to rotate. It goes up and down by doing this. Further, the arm body 10 is provided with an actuator 15 that drives the arm 11 in the direction of arrow C.

A robot hand 17 extending upward and downward via a single-shaped bracket 16 is provided at the tip of the arm 11, and an actuator 18 that rotationally drives the robot hand 17 about a vertical axis as a rotating wheel. There is. The robot hand 17 is shaped to extend upward and downward so that it can also chuck the work 2 placed on the bottom 3a of the pallet 3.

A chuck 19 having chuck claws 19a that engages with the workpiece 2 is provided at the lower end of the robot hand 17. An R-image camera 20 connected to the image processing device F20A is installed above the pallet 3 to take an image of the pallet 2 placed on the pallet 3.

Reference numeral 21 denotes a 113tIIl device, which is supplied with data on the position of the work carried by the image carrying camera 20 from the image processing device, and based on this data, operates each operating part of the industrial robot 1 to move the work 2 in the pallet 3. is transferred to conveyor 5.

Control device H21C, CPU21A, and workpiece placement position H+
, H2*Ha, etc., and the detection signal from the workpiece direction detection device 1B, the workpiece is oriented so that the workpiece placement direction is a constant direction when the workpiece 2 is placed on the conveyor 5. It has a work direction correction means 2IC for correcting.

As shown in FIG. 2, a workpiece direction detection device is installed at the end of the entrance side of the conveyor 5, that is, in the middle of the transfer path where the workpiece 2 is transferred.
1B is provided. As shown in FIGS. 3(A) and 3(B), this workpiece direction detection device 1B is mounted on a bracket 33.
A pair of sensors 34 and 35 are provided. Light emitting elements 34A and 35A are provided at a predetermined interval on the upper part 33a of the bracket 33, and light receiving elements 348 and 358 are provided on the lower part 33t of the bracket 33.

It is provided at a position opposite to 35A. Therefore, the first
The sensor 34 is composed of a light emitting element 34A and a light receiving element 34B, and the second sensor 35 is composed of a light emitting element 35A and a light receiving element 3.
Consists of 5B.

The workpiece 2 is then moved to the robot hand 17 as described later.
In the process of being chucked by the chuck claw 19a and transferred to the conveyor 5, it passes between the light emitting elements 34A, 35A and the light receiving elements 34B, 358.

Since the workpiece 2 is chucked by the chuck claw 19a engaging with the large-diameter through hole 2c, the O-bot hand 17 is rotated by the actuator 18 for driving the wrist, and the part protruding from the chucking part, That is, the portion having the small diameter through hole 2d passes between the light emitting elements 34A, 35A and the light receiving elements 348, 358.

At that time, the light receiving elements 348, 358 are the light emitting elements 34A, 35.
When it receives light from A, it turns on and outputs a signal according to the shape of the workpiece that has passed through it. Specifically, as shown in FIG.
The shape of the workpiece will be detected. A waveform diagram of the output signal at that time is shown in FIG.

Here, the shape of the workpiece 2 will be explained. Figure 6 (A
), (B), the workpiece 2 is formed in the shape of a bowl with an opening at the bottom, the side surface 2a is inclined, and the upper part 2b has a large diameter first through hole 2C and a small diameter first through hole 2C. 2 through hole 2d
and is drilled.

Therefore, a space 2e is formed inside the workpiece 2, and the workpiece 2 is placed with the peripheral edge 2f as the bottom surface.

That is, the workpiece 2 is placed in the pallet 3 as shown in FIG. 7(A).
As shown in (B), they are placed on the bottom plate 22 in irregular orientations and stacked in multiple stages (three stages in this embodiment). At that time, the workpiece 2 has a through hole 2c.

The upper part 2b having 2d is placed so as to face L.

Therefore, when the robot hand 17 chucks the workpiece 2, since the peripheral side surface 2a of the workpiece 2 is inclined, the robot hand 17 does not grip the outer circumference of the workpiece 2, but chucks the workpiece 2 by drilling into the upper part 2b. The chuck claw 19a is engaged with the first through hole 2c.

In FIG. 7, the heights H+, H2, and Hs of the upper part 2b of each stacked workpiece 2 are set in the memory 21B in the control device 21, and the industrial robot 1
Transfer in order from

Here, the configuration of the tip portion of the robot hand 17 will be explained with reference to FIG. In FIG. 5, the chuck 19 is configured to simultaneously displace three chuck claws 19a in the m1 opening direction when a piston (not shown) of an actuator 23 moves up or down by supply of compressed air. still,
Since the mechanism for transmitting the piston displacement to the chuck claw 19a is well known, its explanation will be omitted here.

As shown in FIG. 9, the chuck claws 19a are provided on the lower end surface 19b of the chuck 19 at intervals of 120 degrees, and when the piston of the actuator 23 moves downward, they are displaced in the direction of arrow X + force, and when the piston moves upward, they are displaced in the direction of arrow X2. Displaced to.

Note that the same operation of the chuck claw 19a is performed by detecting a detected member (made of metal) provided on the piston rod 23a that is integrated with the piston.
23b is a proximity sensor (for example, a high frequency oscillation type proximity sensor)
It is detected by moving downward to a position close to 24. Then, the piston of the actuator 23 is stopped by cutting off the supply of compressed air in response to the detection signal from the proximity sensor 24, and the chuck claw 19a is held at the position where it engages with the workpiece 2.

Guide members 25 guide the insertion operation of the chuck claws 19a, and are arranged on the lower end surface 19b of the chuck 19 alternately with the chuck claws 19a.

Further, the guide member 25 protrudes downward from the chuck claw 19a, and its outer surface 25a is inclined so that it can be easily inserted into the through hole 2C. It has a contact portion 25b.

Furthermore, a marker 2 is placed on the inside 125c of the negative guide member 25.
is placed in the opposite direction, or the chuck jaw 19
A detection mechanism 26 is provided to detect when a comes close to another member. This detection mechanism 26 includes a bracket 27 attached to an inner wall 25c of a guide member 25, a rod 28a inserted into a through hole 27a of the bracket 27, a contact portion 28b provided at the lower end of the rod 28a, and a rod 28a inserted into a through hole 27a of the bracket 27.
It consists of a detected portion 28C provided at the upper end of the sensor 8a, and a proximity sensor 30 (high frequency oscillation type proximity sensor) supported by a support member 29 extending from the bracket 27. rod 2
8a, the contact portion 28b, and the detected portion 28G, the detection member 28 is normally in a position moved downward in the direction of arrow Y1 by the pressing force of the spring 31 and its own weight. The proximity sensor 30 detects that the detecting member 28 is moving downward due to the proximity of the detected member 28c, that is, that there is no obstacle.

Further, the detected member 28c also functions as a stopper to prevent the detection member 28 from falling.

Therefore, when the robot hand 17 comes close to another member such as an obstacle while descending, the detection member 28 comes into contact with the contact portion 28b and moves relatively upward in the direction of the arrow Y2. As a result, the detected portion 28C is separated from the proximity sensor 30, so the proximity sensor 30 cannot be switched to the OFF state.

A workpiece detection member 32 detects the position of the upper part 2b of the workpiece 2 and outputs a detection signal when the chuck claw 19a passes through the through hole 2C of the workpiece 2. That is, when the contact portion 32a of the workpiece detection sensor 32 comes into contact with the upper part 2b of the workpiece 2, the zero point 32b relatively enters into the cylinder 32c. A piston 32e energized by a coil spring 32d is provided at the upper end of the rod 32b.
A magnet (not shown) is embedded therein.

The piston 32e approaches the magnetic sensor 32f when the chuck claw 19a passes through the through hole 2C. As a result, the magnetic sensor +) 32f detects that the workpiece 2 is present and also detects that the chuck claw 19a has descended to a position where it can be chucked.

Next, the robot hand 17 having the above configuration and the industrial robot 1 in which the robot hand 17 is attached to the arm 11
The operation of A will be explained.

First, the pallet 3 is imaged by the imaging camera 20 of the image processing device 2OA, and the center position of the large diameter through hole 2C of each workpiece 2 placed on the pallet 3 is read as the X and Y coordinates. Next, an operation command signal is transferred to each of the seven actuators of the industrial robot 1 based on the X and Y coordinate data. As a result, as shown in FIGS. 1 and 2, each operating part of the industrial robot 1A operates and the robot hand 1
7 is moved above the through hole 2C of the workpiece 2. continue,
In the industrial robot 1A, the arm body 10 descends and the chuck claw 19a of the robot hand 17 is inserted into the through hole 2 of the workpiece 2.
Insert into C.

As shown in FIG. 10, when the workpiece 2 is detected by the workpiece detection member 32, the seven cutter 23 of the chuck 19
is supplied with compressed air as a driving source, thereby driving the chuck jaws 19a in the arrow x1 direction (opening direction). In this way, the chucked workpiece 2 is taken out from the pallet 3 by the operation of the industrial robot 1A regardless of its orientation, and as the rotation base 8 rotates, the workpiece 2
It rotates counterclockwise in the figure and is transferred onto the conveyor 5.

The arm 11 of the industrial robot 1A temporarily stops at the position shown by the two-dot chain line during the process from the chucking position shown by the solid line to the workpiece placement position shown by the one-dot chain line. At this time, the workpiece 2 is the wrist drive actuator 1 as described above.
The robot hand 17 is rotated in the horizontal direction by the driving force of the robot hand 17, and passes through the workpiece direction detection device 1B.

Here, the operation of detecting the chucking direction of the workpiece 2 by the workpiece direction detection device 1B and correcting the workpiece direction so that the orientation of the workpiece 2 is constant will be described.

111m 1 unit! ! The CPU 21A of 21 executes the processes shown in FIGS. 11 to 14 depending on the type of signal output from the workpiece direction detection device 11B.

In FIG. 11, the chucked workpiece 2 is detected by a sensor (Sl) of workpiece direction [111B].

When both outputs from 34 and 35 are on (step $1), the workpiece 2 is rotated in the + direction (cutting direction) in FIG. 4 together with the robot hand 17 (step 82). Incidentally, when both sensors 34 and 35 are on, they face the θ voltage or −0I position (see FIG. 4).

Next, as the workpiece 2 rotates clockwise, the sensor (S+) 34 turns off and the sensor (Sl) 35 turns on (step S3), that is, the sensors 34 and 35 face each other at the θ2 position. The workpiece 2 is further rotated clockwise (step S4). Next, sensor (S blind) 34.
(82) Confirm that both 35 are turned off (step S5). Since this position is the position of θ3, in step S5 the sensor (S+) is 34° (82) 35
Even after both are turned off, the workpiece 2 is rotated clockwise (step 86). When the small diameter through hole 2d of the workpiece 2 reaches a position facing the sensor 34, the sensor (S
+) 34 is turned on, the sensor (82) 35 remains off (step S7), and at that point the rotation of the workpiece 2, that is, the rotation of the robot hand 17 is stopped (step S38).

In the next step S9, the correction amount up to θ0+θ4 is set. Next, the workpiece 2 is placed on the workpiece by an angle obtained by adding the above correction amount + 64 to θ to the angle with the workpiece direction when it is placed on the workpiece direction detection position (the position indicated by the dashed line in Fig. 2). The robot hand 17 is rotated while being transferred to the installed position (step 510). As a result, robot hand 1
While correcting the orientation of the workpiece 2 chucked in the workpiece 7 in a certain direction (as shown in FIG. 2), the workpiece 2 is transferred onto the conveyor 5, and at the same time, the chuck claw 19a is displaced in the opening direction to move the workpiece 2 to the next step. (Step 5)
11).

Incidentally, in step S1 above, the sensors 34 and 35 are -
Even if the workpiece 2 is at the position 01, if the workpiece 2 is rotated clockwise by about 300 degrees, it will reach the position θ1, so that the same processing as above is executed.

In FIG. 12, when the output of the sensor (S+) 34 of the work direction detection device 33 is off and the output of the sensor (82) 35 is on for the chucked work 2, the sensor 34 is removed (step 521). .35 is at the θ2 or -θ2 position of the work 2, and the work 2 is rotated in the middle direction (direction) in FIG. 4 (step 522).

Then, as the workpiece 2 rotates clockwise, the sensor 34 is turned on, and it is confirmed that the sensor 35 is also turned on (step 523).

In this step 823, when both sensors 34 and 35 are turned on, they are at the -θ1 position, so the rotation of the robot hand 17 is stopped (step 524).
The workpiece 2 is rotated in the - direction (counterclockwise in FIG. 4) opposite to the above (step 525).

In the next step 826, sensor 34 is off, sensor 3
5 is turned on (-θ2 position), and further rotates the workpiece 2 counterclockwise (step 52).
7). Next, in step 328, it is checked whether the sensors 34 and 35 are both turned off (position -03),
Furthermore, workpiece 2 is rotated counterclockwise (step 5
29).

As described above, when the workpiece 2 rotates counterclockwise and the sensor 34 is turned on and the sensor 35 is turned off, it is determined that the workpiece 2 is at the -θ4 position (step 530), and the rotation of the workpiece 2 is stopped ( Step 531).

Then, the correction layer -θ4 is set (Step 532), and the orientation of the workpiece 2 is corrected by θ-04 (Step 5).
33). Next, the process moves to step 11 in FIG. 11, and the workpiece 2 is placed on the conveyor 5.

In step 823, when the workpiece 2 is at the position θ1, even if the workpiece 2 is rotated clockwise, the sensors 34, 3
5 will not turn on. In this case, the process moves to step 34 and the workpiece 2 is roughly rotated clockwise. after that,
After confirming that both sensors 34 and 35 have reached the off position (position θ3) (step 835), the workpiece 2 is further rotated clockwise (step 836), and the sensor 34 is turned on and the sensor 35 is turned on. It is confirmed that the position remains off, that is, that the position θ4 has been reached (step 537).

When the sensor 34 is turned on and the sensor 35 is turned off in this step 837, the rotation of the workpiece 2 is stopped (step 838), and then the correction image θ4 is set (step 839).
The orientation of the workpiece 2 is corrected by an angle of θ+84 (step 540), and the process moves to step 811 as described above.

Next, in FIG. 13, the chucked work 2
On the other hand, when both the sensors 34 and 35 are off (step 341), the sensors 34 and 35 detect θ3 of the workpiece 2.
or -θ3 position, and the workpiece 2 is rotated clockwise in FIG. 4 (step 542). Then, as the workpiece 2 rotates in the i-needle direction, the sensor 34 turns on and the sensor 35 turns on (step 543). Since the workpiece 2 is at a position of one θ2, the process moves to step 344 and the workpiece 2 is rotated counterclockwise. Rotate.

Incidentally, the processing from steps 844 to 850 is the same as the processing from steps 827 to 833 shown in FIG. 12, so the explanation thereof will be omitted. Further, the step 850 is moved to step 311 in FIG. 11, where the orientation of the work 2 is corrected as described above and the work 2 is placed on the conveyor 5.

In step 843, if the sensor 34 is off and the sensor 35 is not on, the sensors 34 and 35 are at the +θ3 position of the workpiece 2, so the process moves to step 851 and the workpiece 2 is further rotated clockwise. Note that the processing from steps 351 to 855 is the same as the processing from steps 836 to 840 shown in FIG. 12, so a description thereof will be omitted.

Next, in FIG. 14, when the sensor 34 is on and the sensor 35 is off for the chucked work 2 (step 861), the sensors 34 and 35 detect the θ of the work 2.
4 or -θ4 position.

In this case, the workpiece 2 is rotated clockwise (step 562), and it is confirmed that both sensors 34 and 35 are detected as off (position -03) (step 563).

Since the processing from step 863 to step 868 is the same as the processing from step 828 to 833 shown in FIG. 12, the explanation thereof will be omitted here.

In this way, the industrial robot 1A
Regardless of the orientation of the workpiece 2, the chuck claw 19a of the robot hand 17 engages with the through hole 2c of the workpiece 2 to chuck it, so the orientation of the workpiece 2 during chucking is not constant and differs each time it is chucked. . However, the work transfer device of the present invention! 11, when the workpiece 2 passes through the workpiece direction detection device 1B, the direction of the workpiece 2 can be reliably corrected in a fixed direction based on the signals obtained from the sensors 34 and 35, so even if the workpiece has a complicated shape, , can be supplied to the conveyor 5 in a fixed orientation.

In the above description, an optical sensor consisting of a light-emitting element and a light-receiving element is used as the sensor 34, 35, but the detection means is not limited to this, and other reflective optical sensors, magnetic sensors, etc. may also be used. Of course. Further, in the above embodiments, the workpiece shape is described as a bowl-like shape having two holes, but the workpiece shape is not limited to this, and may be any other complicated shape with unevenness.

Effects of the Invention As described above, the workpiece transfer device according to the present invention detects the shape of the workpiece by the detection means provided in the middle of the transfer path along which the workpiece is transferred, and determines that the orientation of the workpiece is in a fixed direction based on this detection signal. In order to correct the orientation of the workpiece so that
After chucking a workpiece placed in an irregular orientation on a pallet regardless of its orientation, the orientation of the workpiece can be easily adjusted based on the shape of the workpiece just before being placed on the conveyor.
, the orientation of the workpiece can be corrected. Therefore, even without using the II image camera for detecting the shape of the workpiece, the rotation angle of the robot hand after chucking the workpiece can be easily adjusted to keep the orientation of the workpiece in a constant direction based on the detection signal obtained from the detection means. It has the advantage of being able to correct

[Brief explanation of the drawing]

1 and 2 are a front view and a plan view, respectively, of an embodiment of the workpiece transfer device according to the present invention, and FIGS. 3A and 3B are a front view and a side view, respectively, of the workpiece direction detection device. Fig. 4 is a plan view showing the position for detecting the workpiece shape, Fig. 5 is a waveform diagram of the signal output from the sensor, and Figs. 6 (A) and (B) are plan views for explaining the workpiece shape, respectively. , longitudinal section, seventh
Figures (A) and <8) are a plan view and a vertical cross-sectional view of the pallet on which the workpieces are placed, respectively. Figure 8 is a vertical cross-sectional view for explaining the chuck part of the robot hand, and Figure 9 is a vertical cross-sectional view of the robot hand. The bottom view, Figure 10 is a millimeter view for explaining the operation when chucking a workpiece, and Figures 11 to 14 are each executed when correcting the workpiece position according to the direction of the chucked workpiece. 3 is a flowchart for explaining the processing performed. 1A...Industrial robot, 1B...Work direction detection device, 2...Work, 3...Pallet, 4, 5...
・Conveyor, 8... Rotating table, 10... Arm body, 11... Arm, 17... Robot hand,
19...Chuck, 19a...Chuck claw, 20.
...*m camera, 2OA... image processing device, 21...
-Control device, 21A... CPU, 21C... Work direction correction means, 22... Scatter plate, 24... Proximity sensor, 25... Guide member, 26... Detection tIAa, 2
8... Detection member, 30... Proximity sensor, 32...
Work detection member, 34.35...sensor. Patent applicant: Tokico Engineering Co., Ltd. Figure 2, Figure 5, Figure 6, Figure 3 (A) (B), Figure 4, Figure 7 (B), Figure 8, Figure 11, Figure 9, Figure 10, Figure 12. Figure 13 Figure 14

Claims (1)

[Scope of Claims] A workpiece transfer device that chucks a workpiece with a robot hand provided at the tip of an arm of a robot, and transfers the workpiece to a predetermined position by the movement of the robot, wherein the workpiece is transferred by the movement of the robot. A detection means for detecting the shape of the workpiece by passing the workpiece is provided in the middle of the transfer path, and the robot hand is rotated based on the signal obtained from the detection means to determine the orientation of the workpiece in the next step. A workpiece transfer device characterized by comprising a workpiece direction correction means for correcting the orientation of the workpiece so that the fixed direction becomes the fixed direction.