JPH02218582A - Robot hand - Google Patents

Abstract

PURPOSE:To surely prevent the breakdown of a chuck, robot hand and robot main body according to the chuck being collided with the bottom plate, etc., on which a work is placed by providing a detection means detecting other members immediately before a chuck claw abutting to the other member at the tip position from the chuck claw. CONSTITUTION:A detection means 26 detecting other members just before a chuck claw 19a abutting to a member is provided at the position of the tip from the chuck claw 19a. In chucking a work in this state, the detection member 28 in the detection means 26 detects other members at the time when the chuck claw 19a is approached to other members. A robot hand 17 is stopped according to this detection signal and the collision of the chuck claw 19a with other members is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a robot hand, and more particularly to a robot hand configured to prevent damage to chuck claws that engage a workpiece.

Conventional technology In the process of automatically supplying workpieces made of castings, etc., to machine tools, when a box-shaped pallet with an opening at the top is transported near the conveyor that supplies the workpieces to the machine tools, the robot operates the arm, and the 1-pot hand attached to the tip of the arm performs the work of chucking the workpieces on the pallet and transferring them to the conveyor. Inside the pallet, a large number of workpieces are stacked in multiple stages via floor plates, and the robot images the workpieces with an imaging camera from the top of the pallet and collects workpiece position data (X,
The robot hand is operated based on the data from the image starting device which outputs the Y data) to take out the workpiece from the pallet.

Problems to be Solved by the Invention For example, if the workpiece is shaped like an arm with an opening at the bottom and has a through hole at the top and cannot be grasped from the outer circumference, the robot hand will be able to insert the chuck claw at the lower end into the through hole. A device is used which is configured to open outwardly and engage the through hole. However, in the workpiece of the above shape, the through hole as the engaging part is provided at the top of the workpiece, so if the workpiece is placed upside down, there will be no space below the throughhole, and the chuck will not be able to fit. You will not be able to king. However, if the upper and lower sides of the workpiece have substantially the same shape, the image carrying camera of the image processing device cannot identify that the workpiece is placed in the opposite direction. Therefore, even if the workpiece is placed in the opposite direction, the robot hand will continue to operate normally.
The chuck claw is inserted into the through hole from the bottom opening of the workpiece. Therefore, with conventional robot hands, even if the workpiece is placed in the opposite direction, the chuck jaws pass through the through hole, and as a result, the chuck jaws collide with the bottom plate, etc. on which the workpiece is placed, and the chuck There was a problem that the claws and the robot hand itself could be damaged.

Therefore, an object of the present invention is to provide a mortar pot hand that solves the above problems.

Means for Solving the Problems The present invention provides a robot hand in which a chuck claw is provided at the tip and engages the chuck claw with an engaging portion formed on the upper part of a workpiece. A detecting means is provided for detecting the other member immediately before the member comes into contact with the other member.

When the chuck claw approaches another member when chucking the workpiece, the detection member detects the other member, thereby stopping the robot hand and preventing the chuck claw from colliding with the other member.

Embodiment FIGS. 1 and 2 show an industrial robot to which an embodiment of the robot hand according to the present invention is applied.

In both figures, an industrial robot 1 is installed between a conveyor 4 to which a box-shaped pallet 3 containing a workpiece 2 is supplied and a conveyor 5 to supply the workpiece 2 to a machine tool (f in the figure). , the works 2 from the pallet 3 are taken out one by one and transferred to the conveyor 5. The industrial robot 1 is a cylindrical coordinate type robot, which has a base 7 fixed to a floor 6, a rotating table 8 provided on the base 7 so as to be rotatable in six directions of arrows, and stands up on the rotating table 8. It has an arm body 10 that moves up and down in the direction of arrow B guided by a pair of guide members 9a and 9b, and an arm 11 that is extendably and retractably provided on the arm body 10.

A ball screw mechanism (not shown) is provided inside the arm body 10 and screws into the male screw 12 on the rotating table 8. It goes up and down by rotating. Further, the arm main body 10 is provided with a seven-cut unit 15 for sliding the arm 11 in the direction of arrow C.

A robot hand 17 extending upward and downward via an L-shaped bracket 16 and an actuator 18 for rotationally driving the robot hand 17 about a vertical axis are provided at the tip of the arm 11. There is. The robot hand 17 is shaped to extend upward and downward so that it can also blow the workpiece 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 2OA is installed above the pallet 3 so as to take all images of the work 2 placed on the pallet 3.

Reference numeral 21 denotes a control device that operates each operating section of the industrial robot 1 based on data on the position of the work carried by the image camera 20, and transfers the work 2 on the pallet 3 to the conveyor 5.

The υ control device 21 includes a CPL 121A and a memory 21B that stores data such as workpiece placement positions H+, H2, H3, etc.
and a robot hand drive means 21C that raises, lowers, or stops the robot hand 17 in response to detection signals from a detection mechanism 26 and a workpiece detection member 32, which will be described later.

Further, an alarm device 33 is connected to the control XI device 21, and as will be described later, when an abnormality occurs in the workpiece chucking process, the alarm device 33 issues an alarm to notify the operator of the abnormality.

Here, the shape of the workpiece 2 will be explained. Figure 3<A
), (8), 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 second through hole 2C. A through hole 2d is bored. Therefore, work 2 has an empty rIJ inside.
2e is formed and placed with the peripheral edge 2f as the bottom surface.

That is, as shown in FIGS. 4(A) and 4(B), the works 2 are placed on the mounting plate 22 and stacked in multiple stages (three stages in this embodiment). At this time, the workpiece 2 is placed so that the upper part 1!12b having the through holes 2G and 2d faces upward.

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. 4, the height positions H+, 82, and H3 of the upper part 2b of each stacked workpiece 2 are the memory 21 in the control device 21.
B, and the industrial robot 1 sequentially transfers the workpieces 2 starting from the topmost stage (height H3).

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 so that when a piston (not shown) of an actuator 23 moves up or down by supply of compressed air, three chuck claws 19a are simultaneously displaced in the locking and opening directions. 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. 6, the chuck claws 19a are provided at angles of 120 degrees on the lower surface 19b of the chuck 19, and are displaced in the direction of arrow ×1 when the piston of the actuator 23 moves downward, and when the piston moves upward. Displaced in the x2 direction.

Note that the opening operation of the buyak claw 19a is such that the piston rod 23a and the installed detected member (made of metal) 23b, which are integrated with the piston, move downward to a position close to the proximity sensor (for example, a high-frequency oscillation type proximity sensor) 24. Detected by Then, the piston of the actuator 23 is stopped by cutting off the supply of compressed air in response to a detection signal from the proximity sensor 24, and the chuck claw 19a is held at a position where it engages with the through hole 2C of the workpiece 2.

Guide members 25 guide the insertion operation of the chuck claws 19a, and are arranged on the lower 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 mark 2 is placed on the inside W25c of the negative guide member 25.
is placed in the opposite direction or the chuck claw 19a
A detection mechanism (detection means) 26 is provided for detecting the proximity of the member to another member.

This detection mechanism 26 is located below the chuck claw 19a and is provided with a bracket 27 attached to the inner wall 25C of the guide member 25, a rod 28a inserted into a through hole 27a of the bracket 27, and a lower end of the rod 28a. A contact portion 28b, a detected portion 28c provided at the upper end of the rod 28a, and a proximity sensor +J30 (high frequency oscillation type proximity sensor) supported by a support member 29 extending from the bracket 27. The detection member 28, which includes the rod 28a, the contact portion 28b, and the detected portion 28c, is normally in a position where it has moved downward in the direction of arrow Y1 due to the pressing force of the spring 31 and its own weight. The proximity sensor 30 detects that the detecting member 28 is moving due to the proximity of the detected member 28G, that is, detects that there is no obstacle. The detected portion 28c also functions as a stopper to prevent the detection member 28 from falling.

Therefore, when the a-bot 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 moves away from the proximity sensor 30, so the proximity sensor 30 is 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, the workpiece detection sensor 32 is supported by the bracket 19G on the side of the chuck 19, and when the contact portion 32a comes into contact with the upper part 2b of the workpiece 2, the rod 32b relatively enters into the cylinder 32C. A coil spring 32d is attached to the upper end of the rod 32b.
A piston 32e energized by the piston 32e is provided.
A magnet (not shown) is embedded in 8. 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 will be explained. When the industrial robot 1 operates, the CPU 21A of the control device 21 executes the processes shown in FIGS. 7(A) and 7(B).

First, a typical chat Vung command will be explained with reference to FIG. 7(A). Image carrier camera 2 of image processing device 2OA
0, the pallet 3 is imaged, and the center position of the through hole 2C of each workpiece 2 placed on the pallet 3 is read as the X, Y coordinates (step S1). Next, based on the X, Y coordinate data, The operation command signal is transferred to each of the seven actuators of the industrial robot 1 (step 82). As a result, as shown in FIGS. 1 and 2, the arm main body 10 is moved upward, the turning table 8 is rotated, and the arm 11 is also moved to move the robot hand 17 to any workpiece 2.
move it above. As shown in FIG. 4(B), the works 2 are stacked in three stages on the pallet 3, so an instruction is given to start from the top stage H3 (step 83).

Then, the height H3 is set and the robot body 10 is lowered (step 84).

As the robot body 10 moves, the robot hand 17
It is confirmed that the proximity sensor 30 of the detection mechanism 26 is turned on until the lower end of the pallet 3 falls to the height H3 of the pallet 3 (step 85). As described above, when the workpiece 2 is placed upside down, the detection mechanism 26 makes contact with the bottom plate 22, turning off the proximity sensor 30 and stopping the robot hand 17. This is provided to prevent the Zebuyak claw 19a from colliding with each other. However, the detection mechanism 26 is used not only when the workpiece 2 is placed upside down, but also when there is an obstacle on the way to the workpiece 2, or when the position of the robot hand 17 is greatly deviated from the through hole 2C of the workpiece 2. 28 is the obstacle or work 2
These can be detected by coming into contact with other members such as the upper part 2b.

As a result, chuck 19. robot hand 17 and r
It is possible to prevent the riding robot main body from being damaged.

When the robot 17 reaches the height H3 position while the proximity sensor 30 of the detection mechanism 26 remains on in step S5, the lowering of the arm body 10 is stopped (step 86).
. In this way, in the process of the robot hand 17 descending to the height H3 position, the workpiece 2
When the workpiece 2 is placed in the normal direction, the detection member 28 of the lowest detection mechanism 26 first enters the through hole 2C of the workpiece 2. Next, guide member 25. Chuck claw 19a
enters the through hole 2C.

In step S7, it is confirmed that the workpiece detection member 32 is turned on, and it is confirmed that the workpiece 2 is present. Step S
When the sensor 32f of the workpiece detection member 32 is turned on in step 7, the chuck claw 19a passes through the through hole 2C and is located in the space 2e of the workpiece 2, and the workpiece detection member 32 confirms the workpiece 2. Therefore, the driving force of the actuator 23 moves the chuck jaws 19a in the direction of the arrow x1 in FIG.
8).

Then, as shown in FIGS. 5 and 8, when the chuck claw 19a comes into contact with the through hole 2C of the workpiece 2 and reaches the position where it engages with the lower surface of the upper part 2b, the detected member 23b of the actuator 23 It is detected by the proximity sensor 24. Therefore, when the detection signal from the proximity sensor 24 is obtained, chucking by the chuck claws 19a is confirmed (step 89). In the next step S10, it is checked whether the workpiece detection member 32 remains in the ON state even after the chucking. If the workpiece detection member 32 is ON, the workpiece 2 is chucked together with the arm body 10. The robot hand 17 is raised (step 511).

When the arm body 10 rises to a height position where the workpiece 2 chucked by the chuck 19 exceeds the upper edge of the pallet a, the turning table 8 in FIG. 2 rotates about 90 degrees counterclockwise. At the same time, the arm 11 is extended and contracted so that the workpiece 2 is positioned above the conveyor 5. Next, the arm body 10 is lowered, the work 2 is placed on the conveyor 5, and the chuck 19 is closed to release the chucking (step 512). As a result, the workpiece 2 is transported by the conveyor 5 to a predetermined machine tool (not shown).
is supplied to

In this way, one workpiece 2 is transferred from the pallet 3 to the conveyor 5, one step of the workpiece transfer operation is completed, and the industrial robot 1 is moved to the work hall position shown in FIGS. 1 and 2. It is restored (step 513). Next step 81
4, it is determined whether or not there is a workpiece 2 on the top floor plate 22, and if the image processing device 2OA recognizes the workpiece 2, the process returns to before the above-mentioned step S1 and steps 81 to 81.
The processing up to 813 is repeated. However, step 81
If the workpiece 2 is not recognized in step 4, the process moves to the next step 815, and a robot (not shown) for taking out the bottom plate is made to take out the topmost bottom plate 22 from the pallet 3.

When the work of taking out the scattering board 22 is completed (step 816
), the data of the lowering height H of the robot hand 17 is updated from H3 to H2 (step 517). If the updated height H is 0, it is assumed that all the works 2 in the pallet 3 have been taken out, and the work of transferring the works 2 to the pallet 3 is completed (step 818). However, if H is not 0 in step 818, the process returns to before step S4 and the processes of steps 84 to 816 are repeated as described above. In this case, the height H2 is set in step S4, and the robot hand 17 is lowered to a position where it can chuck the workpiece 2 on the second stage.

Therefore, based on the image from the imaging camera 20, <X, Y
Each operating section operates according to the data to transfer each workpiece 2 to the second stage and further to the first stage.

In the stop-up S5, when the detection mechanism 26 is switched off when the robot hand 17 reaches a predetermined height position, the robot hand 17 is stopped as if there is some obstacle (step 519). Further, the robot hand 17 is raised (step 52
0) The alarm device 33 issues an alarm to notify the operator of the presence of an obstacle.

Note that when there are a plurality of workpieces 2, the industrial robot 1 sequentially transfers the workpieces 2 starting from the imaged workpiece. For example, the height of the upper part 2b of the workpiece 2 placed upside down is lower than that of the correctly placed workpiece 2, so when the pallet 2 is imaged by the imaging camera 20, a clear image of the correctly placed workpiece 2 is obtained. Therefore, the image of workpiece 2 placed in the opposite direction becomes somewhat unclear. Therefore, after the industrial robot 1 transfers the workpiece 2 placed in the correct orientation, it moves on to the operation of transferring the workpiece 2 in the opposite direction.

Here, the case where the workpiece 2 is placed upside down as shown in FIG. 9 will be explained.

As shown in FIGS. 4(A) and 4(B), the work 2 is placed on the bottom plate 22 in the pallet 3. In some cases, as shown in FIG. It may be placed in the opposite direction, with the peripheral edge portion 25 positioned above. However, from above pallet 3,
Even if the workpiece 2 is placed correctly or in the opposite direction, the image pickup camera 20 that performs Hlgl cannot determine which one it is because its shape when viewed from above is a path. .

Therefore, even if the workpiece 2 is in the opposite direction, the industrial robot 1
performs the normal operation and lowers the robot hand 17 to a predetermined chucking position as described above. However, as shown in FIG. 9, when the workpiece 2 is placed in the opposite direction, even if the lower end portion of the robot hand 17 descends to the height H3, the upper part 2b of the workpiece 2 remains at the bottom. Therefore, in step S7, the workpiece detection member 32
remains off.

In this case, the CPU 21A of the IJIIm device 21 executes the work device detection operation shown in FIG. 7(B).

That is, when the workpiece detection member 32 is off even though the robot hand 17 has descended to the predetermined height H3, the process moves to step 831 and the chuck 19 is operated at the same time, and then the workpiece detection member 32 is turned on. The robot hand 17 is located at a distance from the center of the through hole 2C of the workpiece 2.
Alternatively, if the workpieces 2 are tilted because the peripheral edges 2 of adjacent workpieces 2 overlap, the workpiece detection member 32
may not work. However, when the chuck claws 19a of the chuck 19 open, the workpiece 2 may be moved. Therefore, the workpiece detection member 32 may be turned on after the chucking operation.

Therefore, in step 832, the workpiece detection member 32
When turned on after chucking operation, step S
Returning to step 9, the processing of steps 89 to 313 is then executed as usual.

However, if the workpiece detection member 32 remains off even after the chucking operation, the process moves to step S33, where the chuck 19 is closed, and it is determined that there is no workpiece 2 (step 534). Therefore, the robot hand 17 has a height H
If the workpiece detection member 32 remains off even though the workpiece 2 has arrived at the robot hand 17, the robot hand 17 is raised without chucking the workpiece 2 (step 535).
.

Then, the number of missed shots is counted as +1 (step 836).

Note that the above operation may be caused by erroneously operating the robot hand 17 to a position where the workpiece 2 is not placed, so the number of missed vibrations is a preset number n times (in this embodiment, for example, the third time). It is checked whether the value has been reached (step 537). Moreover, if it is less than 0 times, the process returns to before step S1 and executes the processes of steps 81 to S13. However, in step 837, if there are n (3) missed vibrations, it is determined that the height setting is incorrect and that there is no workpiece 2 in the third stage (step 838), robot hand 1.
The data of the height H, which is the lowering position of No. 7, is changed from H3 to H2 (step 539).

Furthermore, in step 840, the X and Y data of the center position of the straight hole 2C of the workpiece 2 are read, and the robot hand 17
lower to the second stage height H2 (step $41)
. Then, Ml detects that the detection mechanism 26 has not been switched off.
(step 542).

When the workpiece 2 is placed in the opposite direction at a height H2 as shown in FIG. It will descend into the space 2e. Since the upper part 2b of the workpiece 2 is at the bottom, the workpiece detection member 32
remains off, and the chuck claw 19a and detection member 2
8 further descends toward the through hole 2C. The detection member 28 below the chuck claw 19a is located in the through hole 2C.
After the detection member 28 is inserted into the bottom plate 22, the detection member 28 comes into contact with the bottom plate 22.

As a result, the detection member 28 moves upward relatively, the detected member 28c moves away from the proximity sensor 30, and the detection mechanism 26 is switched to the OFF state. In the start-up S42, when the detection mechanism 26 is turned off as described above, the process moves to step 843 and the robot hand 17 is stopped. Therefore, it is possible to prevent the chuck claw 19a from colliding with the bottom plate 22,
Chuck jaw 198 and robot hand 17. Arm 11
etc. can be prevented from being damaged. Therefore, even if the workpiece 2 is placed in the opposite direction, the occurrence of the above-mentioned damage etc. is reliably avoided and the reliability of the industrial robot 1 is further improved.

In step 844, the robot hand 17 is raised from the height H2, and the alarm 33 issues an alarm to notify the operator that the workpiece 2 is facing in the opposite direction (step 545).

In this way, when chucking the workpiece 2, the workpiece detection member 32 does not turn on even if the robot hand 17 descends to a predetermined height as described above, and the number of missed swings without a workpiece is 0 (for example, 3 times). ), the detection mechanism 26 detects that the workpiece 2 is placed upside down, so there is no possibility of incorrectly determining that the workpiece 2, which is placed correctly, is upside down. , the work reciprocal detection operation can be performed more reliably, and the reliability of the blowing operation can be increased.

In the above description, the workpiece 2 having the shape shown in FIG. 3 was used, but other shapes may be considered as the workpiece shape. Furthermore, it goes without saying that the robot is not limited to a cylindrical coordinate robot.

Furthermore, in the above embodiment, the detection member 28 is
Although the displacement of the sensor is detected, it is of course possible to use other sensors such as a reed switch, a magnetic sensor, etc., or a contact type sensor such as a limit switch.

Effects of the Invention As described above, the robot hand according to the present invention is provided with a detection means for detecting other members at a position at the tip of the chuck jaw. Even if the workpiece is placed upside down, the robot can be stopped at the point where the chuck jaws collide, and the chuck collides with the bottom plate on which the workpiece is placed, causing damage to the chuck, the robot hand, and even the robot. It is possible to reliably prevent the main body from being damaged, and it is possible to further improve the reliability of the robot system. In addition, the detection means can detect obstacles other than workpieces even if they are placed inside the pallet, so even if an obstacle is placed inside the pallet while the robot hand is operating, it will not interfere with the obstruction. It has the advantage of being able to avoid collisions.

[Brief explanation of the drawing]

1 and 2 are a front view and a plan view of an industrial robot equipped with an embodiment of the robot hand according to the present invention, and FIGS. 3A and 3B are a plan view and a longitudinal section of a workpiece. Figure, 4th
Figures <A) and (B) are a plan view and a vertical sectional view showing the workpieces placed in the pallet, and Figure 5 is an enlarged view showing the main parts of the robot hand, ff! Figure 6 is a bottom view of the chuck of the robot hand viewed from below, Figures 7 (A) and (B) are flowcharts to explain the processing performed by the 1113111 device, and Figure 8 shows the workpiece placed in the correct orientation. A vertical cross-sectional view to explain the operation during chucking,
FIG. 9 is a longitudinal cross-sectional view for explaining the operation when attempting to chuck a workpiece placed in the opposite direction. DESCRIPTION OF SYMBOLS 1... Industrial robot, 2... Workpiece, 3... Pallet, 4.5... Conveyor, 8... Rotating table, 10... Arm body, 11 River arm, 17... Robot hand, 19... Chuck, 19a... Chuck claw, 20... l1lI11 camera, 21... Control device, 22... Bottom plate, 24... Proximity sensor, 25
...Guide member, 26...Detection mechanism, 28...Detection member, 30...Proximity sensor, 32...Workpiece detection member, 32a...Contact part, 32f...Magnetic sensor,
32e...piston. Figure 2 Conveyor Figure e Figure Figure l

Claims (1)

[Scope of Claims] A robot hand in which a chuck claw is provided at the tip and engages the chuck claw with an engaging portion formed on an upper part of the workpiece, wherein the chuck claw is disposed at a position further to the tip than the chuck claw. A robot hand characterized in that it is provided with a detection means for detecting another member immediately before it comes into contact with the other member.