JPH0487788A - Robot hand - Google Patents

Abstract

PURPOSE:To clamp-pull up a workpiece by a hand of single kind, even when the workpiece is placed in unequal size, position, angle and surface conditions, by cutting off a sucker, not closely attached to the workpiece, of a plurality of the sucker from a vacuum pump, and automatically select-actuating only the sucker closely attached to the workpiece. CONSTITUTION:At work time for sucking a workpiece, a sucker 43 of sucking the workpiece W and that of not sucking the workpiece W are discriminated by a suction discriminating means. An opening/closing valve 20 in an air circuit 18, connected to the sucker 43 of not sucking the workpiece W, is closed. Accordingly, a vacuum pump sucks air not from the sucker 43 of not sucking the workpiece W but from only the sucker 43 of sucking the workpiece W. Consequently, a degree of vacuum in the inside of the sucker 43 of sucking the workpiece W can be generated in a value sufficient for sucking the workpiece.

Description

Detailed Description of the Invention A.Objective of the InventionJ.Field of Industrial Application] The present invention provides a system in which suction cups are respectively connected to a plurality of air circuits connected to a vacuum pump, and the plurality of suction cups are sucked by the vacuum pump. The present invention relates to a negative pressure suction cup type robot hand that presses against a workpiece to attract the workpiece.

[Prior Art] In order to load and unload workpieces such as bags or boxes of cement, powdered milk, sugar and salt onto pallets, various types of suction cup robot hands are used instead of manual work. The above-mentioned suction cup type robot hand can be used to improve the accuracy of workpieces when the shapes and sizes of the workpieces are different. Even if the workpiece is not aligned in direction, posture, etc., or if the workpiece surface is uneven, it must be configured so that it can reliably adsorb the workpiece and prevent the workpiece from falling during transportation. There is. For this reason, various suction cup type robot hands have been developed.

For example, Japanese Patent Application Laid-Open No. 61-214989 discloses that by associating the address assigned to each of a large number of suction elements with the shape of the workpiece, and causing only the suction elements in contact with the workpiece surface to perform suction operation, one type of hand It can reliably pick up workpieces of various sizes.

An apparatus for operating is disclosed. In addition, Unexamined Japanese Patent Publication No. 1-16
Publication No. 388 discloses a hand having at least two fingers each having a flexible tip and an I-shaped suction part, and a hand that controls the fingers so that each suction part hits a target object at an appropriate position and angle. A device is disclosed that is equipped with a controller for controlling objects of various shapes. Furthermore, JP-A-60-180796 discloses a device that uses a combination of a suction cup and a claw to securely grip a bag such as cement without damaging it and convey it to a predetermined location reliably and quickly. There is.

[Problems to be Solved by the Invention] However, the conventional devices disclosed in the above publications have the following problems.

In other words, the invention described in JP-A-61-21'4989 requires inputting the shape of the workpiece in advance, so it is not suitable for gripping workpieces with irregular sizes and surface shapes, and is not effective. The device for dynamically transporting and operating the suction cup is complicated.6 In particular, the part that detects the position and shape of the workpiece is large-scale. Also, the #
The invention described in TF Patent Publication No. 1-16388 improves the performance of each finger, but if there is even one suction cup that does not touch the workpiece, it is difficult to obtain the required suction pressure with one vacuum pump. Not possible, and furthermore, the above-mentioned JP-A-60
In the invention described in Japanese Patent No. 180796, it is difficult to grasp bag workpieces lined up without gaps, and there is also a high risk of damage to the bags by nails.

In view of the above-mentioned problems, the present invention provides an object to easily and reliably grip a workpiece with irregular size, position, angle, surface condition, etc., without performing complicated preliminary work, and without damaging the workpiece. The purpose of the present invention is to provide a robot hand that can perform the following functions and is also cost-effective.

B1 Configuration of the Invention [Means for Solving the Problems] In order to solve the above problems, the robot hand of the first invention of the present application has a suction cup connected to each of a plurality of air circuits connected to a vacuum pump, and A negative pressure suction cup type robot hand in which a plurality of suction cups sucked by a pump are pressed against the workpiece to suction the workpiece, and each of the air circuits is provided with an on-off valve, and the workpiece suction work by each of the suction cups is provided. At the same time, a suction identification means is provided to distinguish between a suction cup to which a workpiece is suctioned and a suction cup to which a workpiece is not suctioned, and a means for closing an on-off valve of the air circuit connected to a suction cup to which a workpiece is not suctioned is provided. It is characterized by

Further, the robot hand of the second invention of the present application is characterized in that the robot hand according to the first invention is
In the robot hand of the invention, the suction identification means includes:
It is characterized in that it is configured by an air volume sensor disposed in each of the air circuits.

[Operation] According to the robot hands of the first and second inventions of the present application described above, during the workpiece suction operation, the suction cup to which the workpiece is suctioned and the suction cup to which the workpiece is not suctioned are distinguished.

Then, the on-off valve of the air circuit connected to the suction cup on which the workpiece is not attracted is closed. Therefore, the vacuum pump suctions air only from the suction cup to which the workpiece is suctioned, without suctioning air from the suction cup to which the workpiece is not suctioned. Because of this, the degree of vacuum inside the suction cup to which the workpiece is attracted can be set to a value sufficient for suction. Therefore, even if some of the suction cups do not attract the workpiece, such as when the positions of multiple suction cups and the workpiece are slightly misaligned, or when the shape of the workpiece is small compared to the area where multiple suction cups are arranged, etc. The workpiece can be gripped easily, reliably, and without damage by the plurality of suction cups that attract the workpiece.

Further, in the robot hand of the second invention described above, during the workpiece suction operation, the means for identifying the suction cup on which a workpiece is suctioned and the suction cup on which a workpiece is not suctioned is constituted by an air volume sensor disposed in each of the air circuits. ing. By the way, during workpiece suction work, the air volume in the air circuit connected to the suction cup that has the workpiece suctioned is O, whereas in the air circuit connected to the suction cup that does not have the workpiece suctioned, air is rapidly sucked from that suction cup. It has a large air volume.

Therefore, during the work suction operation, the air volume sensor can easily distinguish between suction cups that are suctioning a work and suction cups that are not suctioning a work.

[Example] Next, an example of the robot hand of the present invention will be described with reference to the drawings.

1 to 4 are configuration explanatory diagrams of an embodiment of the robot hand of the present invention.

In FIG. 1, a fixed table 2 is supported at the upper end of a support stand 1 installed on the floor. A rotary table 3 is rotatably supported on the upper surface of the house table 2.

This rotary table 3 has a cylindrical inner surface (not shown) and a ring-shaped rack provided along the cylindrical inner surface, and this rack is rotated by a drive motor (not shown) supported by the fixed table 2. It meshes with a driven pinion (not shown). When the binion is rotationally driven by the drive motor, the rotary table 3 is configured to be rotationally driven around a vertical axis on the fixed table 2.

A base end portion of a first arm 4 is rotatably supported on a rotary table 3, and a longitudinal intermediate portion of the first arm 4 and the rotary table 3 are connected by an air cylinder 5 for raising and lowering the first arm. connected. A base end portion of a second arm 6 is rotatably connected to a distal end portion of the first arm 4 . There is a second arm between this second arm 6 and the first arm 4.
An arm operating air cylinder 7 is provided, and the angle of the second arm 6 with respect to the first arm 4 is adjusted by expanding and contracting the second arm operating air cylinder 7.

The upper end of a suspension block 8 is swingably connected to the tip of the second arm 6. A connecting block 9 is provided at the lower end of the suspension block 8. A connecting plate 9a is fixed to the upper surface of this connecting block 9, and the lower surface of the connecting block 9 is connected to an upper support member 10 of a robot hand H, which will be described next.

The upper support member 10 includes an upper support plate 11, and two guide columns 12, 12 are erected at the center of the upper support plate 11. These two guide columns 12.12 pass through flanges at the upper and lower ends of the air cylinder 13, and their upper ends are connected to the connection block 9.

The upper support plate 11 also includes a guide member 15 on the outside of the two guide columns 12, 12 in FIG.
．． 15 is supported, and guide holes 16, 16 are provided on the outside of this guide member 15.15. The upper support member 10 is constructed from the components indicated by the numerals 11 to 16.

The upper support plate 11 also includes an air circuit support frame 17.17 on the outside of the guide hole 16.16 in FIG.
is supported. Each air circuit support frame 17 supports three air circuits 18. ing. In this embodiment, a gas flow switch (manufactured by Tokyo Keiso Co., Ltd., TD-1000) is used as the air volume sensor 19, and a solenoid valve (manufactured by Sintered Metal Co., Ltd., VP
542R-ITO3B-F) was used. Further, each on-off valve 20 is connected to a communication duct 2 via a connecting pipe 21.
Connected to 2.

The air inside the communication duct 22 is connected to the connecting plate 1.
The vacuum pump 24 installed on the floor (in this embodiment, a 40 N V 5 M manufactured by Zansoku Manufacturing Co., Ltd. was used as the vacuum pump 24) sucks the air through a communication path 23 supported by the ing.

Further, the lower end of the piston rod 13a of the air cylinder 13 supported by the upper support member 10 is connected to the lower support member 3.
0 connection bracket 31. This connection bracket 31 is connected to the center of the lower support plate 33. As shown in FIGS. 1 and 3, lower ends of guide rods 34.34 are connected to the left and right outer sides of the connection bracket 31 to the lower support plate 33, and guide rods 35.35 are connected to the outer sides of these. The bottom ends are connected. The upper end portions of the two guide rods 3434 are slidably fitted into the guide member 15.15, and the upper end portions of the two guide rods 35.35 are the guide members of the upper support member 10. It is slidably fitted into hole 16.16. Further, as can be seen from FIG. 13, the lower support plate 33 has a total of six sliding bearings 36.
is supported. The lower support member 30 is constituted by the components indicated by the numerals 31 to 36.

As shown in FIG. 1.4, a suction cup support rod 37 is slidably supported on the sliding bearing 36. The suction cup support rod 37 has a flat part 37a for preventing rotation formed by cutting a part of the cylindrical side surface, and corresponding to this flat part 37a, the sliding bearing 36 also has a flat part (
(not shown) is provided. This prevents the nitrogen absorption support rod 37 from rotating around its axis. A suction cup support rod 37 is provided at the upper end of the nitrogen suction support port/l door 37.
A bubble plate 38 is fixed to prevent the lower part from falling. In addition, the nitrogen absorbing support rod 3
The lower end of 7 is connected to an air box 39. A compression spring 40 for buffering is disposed between the upper ends of the three air boxes and the lower end of the sliding bearing 36, and the air box 39 is constantly pressed downward by the compression spring 40.

As shown in FIG. 4, spherical bearings 41 are disposed within the three air boxes, and the air circulation pipe 42 is rotatably supported by the spherical bearings 4. A suction cup 43 is connected to the lower end of the air circulation pipe 42, and the suction cup 43 and the air circulation pipe 42 are rotatable by the spherical bearing 41. In this embodiment, the suction cup 43 has a contact portion made of rubber, an outer diameter of 80t+i,
A oscillating band with a buffer having an inner diameter of 50 mm+ (manufactured by Sintered Metal Co., Ltd., IN○-3769-63-8ON) was used.

The inside of the suction cup 43 is communicated with the inside of the air box 39 through an air distribution pipe 42.The inside of this air box 39 is then connected to the air circuit 18 through a connecting pipe 44, as shown in FIG. . Further, a proximity sensor 45 (in this embodiment, the proximity sensor 45 is disposed at the center of each sliding bearing 36 and is located at the lower end of the two fS
5, photoelectric switch, E3S-DS manufactured by Omron Corporation
30E41 is used)), and the distance between this proximity sensor 45 and the lower surface of the nitrogen absorber 43 is usually about 15 cm. When the suction cup 43 is pressed against the workpiece W, the lower support member 30, the proximity sensor 45, etc. approach the workpiece W while compressing the compression spring 40. The proximity sensor 45 is configured to operate when the workpiece W approaches a position of about 10c+a.

FIG. 5 is a detailed explanatory diagram of the air circuit 18.

In FIG. 5, each of the six suction cups 43 is connected to the air circuit 18 via an air distribution pipe 42, an air box 39, and a connecting pipe 44, respectively.

The air volume detection signal from the air volume sensor 19 of the air circuit I8 is output to a controller 46 (in this embodiment, 82HOB manufactured by Kairitsu Giken Co., Ltd. is used as the controller 46).
opens and closes! It is configured to be controlled by IJ. The controller 46 also receives an input signal from an input device 47 for inputting a 1 work mode selection command signal and work data,
Detection signals from various sensors 48 for detecting the rotational position of the rotary table 3, the expansion/contraction state of the air cylinder 13, etc., and the workpiece detection signal from the proximity sensor 45 are input. The controller 46 is connected to the input device 4
According to input signals from 7 and the position sensor 48, programs stored in a built-in memory, etc., drive signals for the air cylinder drive device 49, rotary table drive device 50, arm actuator 51, etc. are output. Then, the air cylinder 13 is driven by the air cylinder drive device 49, and the rotary table drive device 50
The rotary table 3 is driven by. Further, the arm actuating device 51 causes the first
The arm raising/lowering air cylinder and the second arm operating air cylinder 7 are activated.

Next, the operation of the embodiment of the present invention having the above-described configuration will be explained.

When performing a work that is stored in advance in the memory of the controller 46, if the work mode selection command signal is inputted to the controller 46 from the input device 47, the controller 46 selects a command from the built-in memory according to the selection command signal. Read the program and start the predetermined work. However, when performing a work stored in the memory of the controller 46, if specific work data necessary for performing the work is required, the specific work data is inputted from the input device N47. In this case, the work data includes, for example, the minimum number of suction cups required to pull up the work W. The minimum number of suction cups required to pull up the workpiece W is a number determined from the load of the workpiece W and the ability of the suction force of the suction cup 43.

Now, as the work W, the contracted size is 60 cm and the width is about 40 CI.
In step 11, use 25 kg packed lactose with unevenness of about 10 cm or more in width and about 3 cm in depth on one surface, and start lifting when 4 or more of the 6 suction cups 43 are effectively adsorbed to the workpiece W. Set it so that

Two seconds after the start of suction, the suction cup 43 connected to the air circuit 18 whose air volume detected by the air volume sensor 19 is 300 cubic cm/sec or more is determined to be insufficiently suctioned, and the opening/closing valve 2
0 and is set to be shut off from the air pump 24.

When the work is started after inputting necessary work data from the input device 47, the controller 46 drives the arm actuating device 51 according to the selected work mode, and activates the first arm raising/lowering air cylinder 5 and the first arm raising/lowering air cylinder 5. The two-arm actuating air cylinders 7 are activated to set them in the appropriate extended and retracted state. Then, the air cylinder drive device 49 is operated to drive the piston rod 13 of the air cylinder 13.
Pull a up to the uppermost position. This piston rod 1
In the state where 3a is pulled up, the piston rod 13&
The suction cup 43 supported by the lower support member 30 at the lower end is at an appropriate distance above the upper surface of the workpiece W (see FIG. 1)! (level). Note that, at this time, the suction cup 43 and the workpiece W are still horizontally misaligned, so the suction cup 43 is not directly above the workpiece W.

In this state, the controller 46 operates the rotary table driving device! 50 to operate the rotary table 3 and move the robot hand H to a position directly above the workpiece W. At this time, the suction cup 43 is located directly above the workpiece W, and is located above the upper surface of the workpiece W by an appropriate distance.

Next, the air cylinder drive device 49 is driven to operate the air cylinder 13 and move the piston rod 13a downward. Then, along with the movement of the piston rod 13a, the lower support member 30, the proximity sensor 45, the six suction cups 43, etc. also move downward. Then, the suction cup 43 comes into contact with the upper surface of the workpiece W. At this time, since the proximity sensor 45 is approximately 15 cm away from the work W, it does not operate yet (does not detect the work W). In this state, the suction cup 43 is prevented from moving downward on the upper surface of the workpiece W, but the lower support member 30 moves further downward. At this time, the suction cup 43 moves upward relative to the lower support member 30. That is, since the air circulation pipe 42, air box 39, suction cup support rod 37, stopper plate 38, etc. connected to the suction cup 43 are prevented from moving downward by the upper surface of the workpiece W, the lower support member 30 and proximity sensor 4
5 and the like further move downward by a predetermined distance while compressing the compression spring 40. When the proximity sensor 45 approaches the work W to a position of about 10 cm, the proximity sensor 45 is activated. In response to the input signal from the proximity sensor 45, the controller 46 stops the air cylinder 13.

At this time, the lower support member 30 and the proximity sensor 45
The downward movement of etc. is stopped. The stopping position of the lower support member 30 is set by the proximity sensor 45 as described above.
Instead of using the sliding bearing 36, the movement amount of the stopper plate 38, the suction cup support rod 37, etc. can also be used.

In this way, when the suction cup 43 is in contact with the upper surface of the workpiece W, the air inside the suction cup 43 is sucked by the vacuum pump 24 driven by the drive motor M (see FIG. 5), so that the workpiece W is attracted to the suction cup 43. At this time, work W rank! If the suction cups 43 shift and bend, one of the six suction cups 43 may not be in contact with the upper surface of the workpiece W. In such a case, the detected air volume of the detection signal from the two air volume sensors 19 does not decrease even after a predetermined time has elapsed after the air cylinder 13 stopped (that is, even after a predetermined time elapsed after the suction cup 43 adsorbed the workpiece W). Therefore, the controller 45 counts the number of air volume sensors 19 whose detected air volume signal does not decrease after a predetermined period of time has elapsed. If the counted number is 3 or more, the number of suction cups 43 that attract the workpiece W is 3 or less, and therefore, in this embodiment, the robot hand H stops working. Then, an alarm lamp (not shown) is lit or an alarm buzzer is sounded to notify the occurrence of an abnormal situation. Further, if the counted number is 2 or less, the number of suction cups that suck the workpiece W is 4.
Because of the above, the air circuit 1 in which the detected air volume signal does not decrease
After closing the on-off valve 20 of No. 8, the work is continued. In this way, by cutting off the suction cups 43 that are not suctioning the workpiece W from the vacuum pump 24, the air in the other suction cups 43 that are suctioning the workpiece W can be reliably sucked, and the suction force can be used to perform the work. continue.

[Test Example] Using the robot hand H and the workpiece W, when the workpiece W is placed approximately horizontally and all six suction cups 43 are in correct contact with the workpiece W (see Fig. 1), the workpiece W is When all six suction cups 43 were made to have an inclination of 100 degrees and all six suction cups 43 contacted the workpiece W correctly (see Fig. 6), the position of the workpiece W was arbitrarily shifted and one suction cup 43 did not contact the workpiece W correctly. (see Figure 7), and when the two suction cups 43 did not properly contact the workpiece (not shown), etc. As a result of repeated pulling tests over 100 times, there was no failure in all cases. I was able to do this.

Although the embodiments and test examples of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes can be made within the scope of the gist of the present invention as described in the claims. It is possible to do this.

For example, the robot hand of the present invention can be used by being connected to the tip of an arm of various shapes or suspended from the bottom end of a rope, and the number of suction cups can be arbitrarily selected. It is. Instead of making the lower support member movable with respect to the upper support member, it is also possible to integrally connect the upper support member and the lower support member so that they cannot move relative to each other. Furthermore, it is also possible to arrange a sensor for detecting a workpiece at a position adjacent to the suction cup, and to control the downward movement of the suction cup based on a detection signal from the sensor.

2. Effects of the Invention] The above-mentioned present invention has the following effects 6. (1) Among the plurality of suction cups, the suction cups that are not in close contact with the workpiece are shut off from the vacuum pump, and only the suction cups that are in close contact with the workpiece are automatically shut off. Since it is selected and activated, even workpieces with irregular sizes, positions, angles, and surface conditions can be grasped and pulled up with a single hand.

(2) Among the multiple suction cups, any suction cup that is not in close contact with the workpiece is shut off by the vacuum pump, so there is no wasted suction energy.Therefore, the adsorption force of the suction cup does not decrease, so if the workpiece falls while it is being pulled up. It is superior in terms of occupational safety and work efficiency.

[Brief explanation of drawings]

Figure 1 shows a device using an embodiment of the robot hand of the present invention! 2 is a side view of an embodiment of the robot hand, FIG. 3 is a sectional view taken along line 33 in FIG. 1, FIG. 4 is an explanatory diagram of the main parts of the embodiment, and FIG. 1 is an explanatory diagram of the control system of the apparatus shown in FIG. 1, and FIGS. 6 and 7 are explanatory diagrams of the operation of the same embodiment. Explanation of symbols H...Robot hand, W...Work, 18...Air circuit, 19...Air volume sensor, 20, Open/close valve, 24...
・Vacuum pump, 43...Sucker, patent applicant Morinaga Milk Industry Co., Ltd.

Claims (2)

[Claims] (1) A negative pressure suction cup type robot hand in which a suction cup is connected to each of a plurality of air circuits connected to a vacuum pump, and the plurality of suction cups sucked in by the vacuum pump are pressed against the workpiece to adsorb the workpiece. Each of the air circuits is provided with an on-off valve, and a suction identification means is provided for identifying a suction cup to which a work is being suctioned and a suction cup to which a work is not being suctioned during work suction by each of the suction cups. A robot hand provided with means for closing an on-off valve of the air circuit connected to a suction cup that is not attracted. (2) The robot hand according to claim 1, wherein the suction identification means is constituted by an air volume sensor disposed in each of the air circuits.