JP7467951B2 - Workpiece suction device - Google Patents

Description

The present invention relates to a workpiece suction device.

As disclosed in Patent Document 1, in a conventional production line, a suction device having multiple suction pads is attached to a hand at the tip of a robot arm, and the hand is used to pick up and remove a workpiece placed in a specified location, and then to move the workpiece to a different location for transport purposes. In this case, the suction pad is made of an elastically deformable resin material or the like, and is designed to attract the workpiece by generating negative pressure on the suction surface. In the above configuration, the opening and closing control of the air valves for controlling the supply and suction of air corresponding to each of the multiple suction pads is generally performed by a single system.

JP 2013-107174 A

In the process where the above-mentioned transport operation is performed, it is expected that the shapes of the workpieces to be transported will be diverse. With the above-mentioned conventional configuration, it may be difficult to accurately pick up multiple types of workpieces with different shapes using the same hand. This is because, with the above-mentioned configuration, when picking up a workpiece with a shape that can only be picked up by some of the multiple suction pads, air leaks from the other suction pads, reducing the degree of vacuum of the suction pad that is being sucked, and weakening the suction force.

The present invention was made in consideration of the above circumstances, and its purpose is to provide a workpiece suction device that can reliably suction multiple types of workpieces that are different in shape.

The workpiece suction device according to claim 1 is attached to the hand of a robot arm that performs a transport operation for transporting a workpiece, and includes a plurality of suction mechanisms for suctioning and holding the workpiece, and an suction control unit that controls the operation of the plurality of suction mechanisms. In this case, the suction control unit divides the plurality of suction mechanisms into a plurality of systems, and controls the operation of the plurality of suction mechanisms independently for each of the plurality of systems. Then, when the transport operation is performed, the suction control unit switches the system that performs the suction operation by the suction mechanisms according to the shape of the workpiece to be transported.

According to the above configuration, if the workpiece to be transported is, for example, a relatively large workpiece that cannot be adsorbed without using all of the suction mechanisms, the workpiece can be reliably adsorbed by executing the suction operation using the suction mechanisms of all systems. In this case, since there are no suction mechanisms that do not contribute to the adsorption of the workpiece, air leakage does not occur as in the conventional configuration. Also, according to the above configuration, if the workpiece to be transported is, for example, a relatively small workpiece that can only be adsorbed by some of the suction mechanisms, the workpiece can be adsorbed by executing the suction operation using the suction mechanisms of some systems that are used according to the shape of the workpiece.

In this case, the suction mechanisms of some of the systems that are used are independent from the other suction mechanisms that are not being used, so even if air leaks occur in the other suction mechanisms that are not being used, the vacuum level in the suction mechanism that is performing the suction operation will not decrease and the suction force will not weaken, and the workpiece can be reliably adsorbed. In this way, with the above configuration, the excellent effect of being able to reliably adsorb multiple types of workpieces that are different in shape can be obtained.

The workpiece suction device according to claim 1 further includes a state detection unit that detects whether there is a problem with the suction state of the workpiece by the suction mechanism. In this case, when the suction control unit detects a problem with the suction state of the workpiece during the transport operation by the state detection unit, in addition to the system that is currently performing the suction operation by the suction mechanism, the suction control unit causes a suction operation by a suction mechanism of a system other than the system. In this way, if a problem such as a breakdown occurs in one of the suction mechanisms of the system that initially performed the suction operation and the suction force weakens, the reduction in suction force can be compensated for by additionally performing a suction operation by the suction mechanism of the other system, and problems in the transport operation such as the dropping of the workpiece can be prevented.

In the workpiece suction device according to claim 2 , when a transport operation for transporting a plurality of workpieces is performed, the suction control unit causes a predetermined workpiece to be sucked and held by a suction mechanism of one of the plurality of systems, and then causes a workpiece other than the predetermined workpiece to be sucked and held by a suction mechanism of another system. In this way, since a plurality of workpieces can be sucked and held at once and then transported, the amount of movement of the robot arm can be kept small, and as a result, the effect of shortening the time required for the transport operation can be obtained.

FIG. 1 is a diagram illustrating a schematic configuration of a production system according to a first embodiment; FIG. 1 is an enlarged view of a hand attached to a robot arm according to a first embodiment; FIG. 2 is a diagram showing an arrangement of suction pads according to the first embodiment; FIG. 1 is a diagram illustrating a schematic configuration of a production system including a controller for a robot arm according to a first embodiment. FIG. 1 is a diagram for explaining a specific example of switching between a plurality of systems according to the first embodiment; 13 is a diagram showing an example of an arrangement of suction pads when the number of suction mechanisms according to the second embodiment is three. FIG. 13 is a diagram for explaining a specific example of switching between a plurality of systems according to the second embodiment; 13 is a diagram showing an example of the arrangement of suction pads when the number of suction mechanisms according to the second embodiment is six. 13 is a diagram showing an example of the arrangement of suction pads when the number of suction mechanisms according to the second embodiment is eight.

Hereinafter, a number of embodiments will be described with reference to the drawings. Note that the same reference numerals are used to designate substantially the same components in the respective embodiments, and the description thereof will be omitted.
First Embodiment
Hereinafter, the first embodiment will be described with reference to FIGS.

As shown in FIG. 1, in the production system 1 of this embodiment, a container 5 for putting in multiple types of workpieces, specifically three types of workpieces 2, 3, and 4, is transported by a conveyor 6, which is a belt conveyor device, and distributed to a production line in a factory. The production system 1 includes a process as shown in FIG. 1, that is, a process in which the workpieces 2, 3, and 4 arranged on a workbench 7 are picked up by a robot arm 8 and placed in an aligned state into the container 5 transported by the conveyor 6. The container 5 is, for example, a rectangular container such as a tray.

The conveyor 6 corresponds to a transport device, and is basically designed to operate continuously without stopping. The works 2, 3, and 4 are bags containing food such as oden and soup, and each has a different shape. Specifically, the work 2 is a bag smaller than the work 3, and the work 3 is a bag smaller than the work 4. In other words, the work 2 is the smallest bag, the work 4 is the largest bag, and the work 3 is a bag of intermediate size. Note that in FIG. 1 and FIG. 4 described later, only some of the works are labeled with reference numbers, and the reference numbers for the other works are omitted.

The robot arm 8 is configured as a horizontal articulated robot having, for example, a four-axis arm. The robot arm 8 performs the task of transporting the workpieces 2, 3, and 4, and is placed on a workbench 9. A hand 10 is attached to the tip of the robot arm 8. As shown in FIG. 2, five suction mechanisms 11a, 11b, 11c, 11d, and 11e are attached to the hand 10 for suctioning and holding the workpieces 2, 3, and 4. Note that when it is not necessary to distinguish between the suction mechanisms 11a to 11e, the alphabet at the end will be omitted and they will be referred to collectively.

As shown in FIG. 2, the suction mechanism 11 includes a suction pad 12 and an expandable section 13. The suction pad 12 is formed in an umbrella shape from an elastically deformable resin material or the like, and generates a negative pressure on its suction surface 14 to suck up the workpieces 2-4 by vacuum suction. The expandable section 13 is a bellows-shaped tube or the like, and is adapted to freely expand or contract or extend when the suction pad 12 sucks up the workpieces 2-4, thereby conforming to the shapes of the workpieces 2-4. With this configuration, when the suction mechanism 11 sucks up and holds the workpieces 2-4, the suction surface 14 reliably adheres to the surface shapes of the workpieces 2-4, preventing air leakage.

In the above configuration, the suction surface 14 of the suction pad 12 can be placed in a negative pressure state to suction and hold the workpieces 2 to 4, and the suction of the workpieces 2 to 4 can be released by placing the suction surface 14 of the suction pad 12 in an atmospheric pressure state. A well-known negative pressure generating device, such as an air valve such as an electromagnetic valve, a compressor, a vacuum pump, a tube, etc., can be used as a configuration for switching the suction surface 14 between a negative pressure state and an atmospheric pressure state. Note that the negative pressure generating device, including the tube connecting it to the suction mechanism 11, is not shown in Figures 1 and 2.

The robot arm 8 rotates the arm to position the tip above the worktable 7 on which the workpieces 2, 3, and 4 are placed, then lowers the hand 10 attached to the tip of the arm, and uses the suction mechanism 11 attached to the hand 10 to pick up and lift the workpieces 2, 3, and 4. The robot arm 8 then rotates the arm to position the tip above the container 5, then lowers the hand 10, releasing the workpieces 2, 3, and 4 from the hand 10 and placing them at a specified insertion position in the container 5. The workpieces 2, 3, and 4 are released from the hand 10 by releasing the suction state of the suction mechanism 11. The robot arm 8 repeatedly performs a series of operations for the workpieces 2, 3, and 4, that is, the operations of removing the workpieces 2, 3, and 4 placed on the worktable 7 and then inserting them into the container 5 being transported by the conveyor 6.

In this embodiment, the suction pads 12 are arranged as shown in Figure 3. Note that Figure 3 is a view of each suction pad 12 of the suction mechanism 11 as viewed from the suction surface 14 side, that is, a view of each suction pad 12 as viewed from below. In the following explanation and Figure 3, each suction pad 12 and each suction surface 14 of the suction mechanisms 11a to 11e are distinguished by being given the same alphabet as the alphabet given to the corresponding suction mechanism 11.

As shown in FIG. 3, suction pads 12a, 12b, 12c, and 12d are arranged so that the lines connecting their centers form a square. Therefore, the distance between the center of suction pad 12a and the center of suction pad 12b, the distance between the center of suction pad 12b and the center of suction pad 12c, the distance between the center of suction pad 12c and the center of suction pad 12d, and the distance between the center of suction pad 12d and the center of suction pad 12a are all the same. Suction pad 12e is arranged so that its center is at the point where the diagonal line connecting the center of suction pad 12a and the center of suction pad 12c intersects with the diagonal line connecting the center of suction pad 12b and the center of suction pad 12d.

The operation of the robot arm 8 and the suction mechanism 11 is controlled by a controller 20 shown in FIG. 4. It is also possible to adopt a configuration in which the operation of the robot arm 8 and the operation of the suction mechanism 11 are controlled by separate control devices. The controller 20 controls the robot arm 8 and the suction mechanism 11 by executing a computer program in a control means made up of a computer including a CPU, ROM, RAM, etc. (not shown).

Specifically, the controller 20 has a drive unit composed of an inverter circuit and the like, and drives each motor by, for example, feedback control based on the rotational position of the motor detected by an encoder provided corresponding to the motor that drives each axis of the robot arm 8. The controller 20 executes a preset operation program to control the robot arm 8 so that each axis of the robot arm 8 automatically performs a predetermined operation.

The controller 20 includes functional blocks such as an operation control unit 21, an adsorption control unit 22, and a state detection unit 23. Each of these functional blocks is realized by a CPU included in the controller 20 executing a computer program stored in a ROM or the like to execute processing corresponding to the computer program, that is, by software. Note that at least a portion of each functional block may be configured to be realized by hardware. In this embodiment, the adsorption control unit 22 and the state detection unit 23, together with the above-mentioned adsorption mechanism 11, constitute a workpiece adsorption device.

The operation control unit 21 controls the operation of the robot arm 8 so as to remove the workpieces 2, 3, 4 from the predetermined removal position and align and place the removed workpieces 2, 3, 4 at the predetermined input position set in advance on the container 5. In this case, the workpiece 2 is sequentially supplied by the feeder 24 to the predetermined removal position, specifically the position of the lower end of the feeder 24 in FIG. 4. The workpiece 3 is sequentially supplied by the feeder 25 to the predetermined removal position, specifically the position of the left end of the feeder 25 in FIG. 4. The workpiece 4 is sequentially supplied by the feeder 26 to the predetermined removal position, specifically the position of the left end of the feeder 26 in FIG. 4.

The suction control unit 22 controls the operation of the multiple suction mechanisms 11. In this case, the suction control unit 22 divides the multiple suction mechanisms 11 into multiple systems, and controls the operation of the multiple suction mechanisms 11, specifically the execution and release of the suction operation by the suction mechanisms 11, independently for each of the multiple systems. The division of the systems is set in advance by the operator through programming, etc., so as to be optimal for accurately suctioning each workpiece according to the shape of the workpiece to be transported.

Specifically, as shown in FIG. 3, the suction control unit 22 divides the opening and closing control of the air valves corresponding to the five suction mechanisms 11a to 11e into three systems S1, S2, and S3, and controls the operation of the suction mechanisms 11a to 11e independently for each system S1, S2, and S3. When the robot arm 8 performs a transport operation, the suction control unit 22 switches between systems S1 to S3 that cause the suction mechanism 11 to perform the suction operation depending on the shape of the workpiece 2, 3, or 4 to be transported.

A specific example of switching between systems S1 to S3 by the suction control unit 22 will be described with reference to FIG. 5. In FIG. 5, the rough outlines of the workpieces 2, 3, and 4 are simply shown by lines. The workpiece 2 has an outline that allows it to be attracted by one suction pad 12. Therefore, when the workpiece to be transported is the workpiece 2, the suction control unit 22 selects system S2 as the system that will carry out the suction operation by the suction mechanism 11, and the workpiece 2 is attracted and held by the suction operation of the suction pad 12 of the selected system S2.

The workpiece 3 has an outer shape that can be adsorbed by two or three suction pads 12. Therefore, when the workpiece 3 is to be transported, the suction control unit 22 selects system S1, systems S1 and S2, systems S2 and S3, or system S3 as the system that will perform the suction operation by the suction mechanism 11, and adsorbs and holds the workpiece 3 by the suction operation of the suction pads 12 of the selected system. In this case, the suction control unit 22 may select the same system each time, but it may also rotate the selected system at a predetermined cycle. In this way, it is possible to prevent some of the suction pads 12 from becoming too worn out and to extend the life of each suction pad 12.

The workpiece 4 has an outer shape that allows it to be adsorbed by four or five suction pads 12. Therefore, when the workpiece 4 is to be transported, the suction control unit 22 selects systems S1 and S3, or systems S1, S2 and S3, as the system that will perform the suction operation by the suction mechanism 11, and adsorbs and holds the workpiece 4 by the suction operation of the suction pads 12 of the selected system.

The state detection unit 23 detects whether there is a problem with the suction state of the workpieces 2, 3, and 4 by the suction mechanism 11, for example, based on the degree of vacuum in the air flow path. The state detection unit 23 can detect such suction state for each of the systems S1 to S3. The suction control unit 22 can execute the following first control and second control based on the result of such detection by the state detection unit 23.

In other words, when the state detection unit 23 detects that there is a problem with the suction state of the workpieces 2, 3, and 4 during the transport operation, the suction control unit 22 can execute a first control in which, in addition to the system in which the suction mechanism 11 is currently executing the suction operation, a suction mechanism 11 in a system other than the system in which the suction operation is currently being executed is executed. Specific examples of such a first control by the suction control unit 22 include the following.

For example, when the workpiece 4 is to be transported, the suction control unit 22 first sucks and holds the workpiece 4 by the suction pads 12 of the systems S1 and S3 using a suction operation. When the workpiece 4 is being held in this manner, if the state detection unit 23 detects that there is no problem with the suction state of the workpiece 4, the suction control unit 22 continues the suction operation by the suction pads 12 of the systems S1 and S3. On the other hand, when the workpiece 4 is being held in this manner, if the state detection unit 23 detects that there is a problem with the suction state of the workpiece 4, the suction control unit 22 executes a suction operation by the suction pads 12 of the system S2 in addition to the suction pads 12 of the systems S1 and S3, thereby maintaining the suction state of the workpiece 4.

For example, when the transport target is workpiece 3, suction control unit 22 first sucks and holds workpiece 3 by a suction operation using suction pad 12 of system S1 or S3. When workpiece 3 is held in this manner, if state detection unit 23 detects that there is no problem with the suction state of workpiece 3, suction control unit 22 continues the suction operation using suction pad 12 of system S1 or S3. On the other hand, when workpiece 3 is held in this manner, if state detection unit 23 detects that there is a problem with the suction state of workpiece 3, suction control unit 22 executes a suction operation using suction pad 12 of system S2 in addition to suction pad 12 of system S1 or S3, thereby maintaining the suction state of workpiece 3.

When the state detection unit 23 detects a problem with the suction state of the workpieces 2, 3, and 4 during the transport operation, the suction control unit 22 can execute a second control in which, instead of the system currently executing the suction operation by the suction mechanism 11, a suction operation is performed by a suction mechanism of a system other than the system. Specific examples of such second control by the suction control unit 22 include the following.

For example, when the transport target is workpiece 3, the suction control unit 22 first suctions and holds the workpiece 3 by a suction operation using the suction pads 12 of one of the systems S1 and S3. When the workpiece 3 is being held in this manner, if the state detection unit 23 detects that there is no problem with the suction state of the workpiece 3, the suction control unit 22 continues the suction operation using the suction pads 12 of one of the systems S1 and S3.

On the other hand, when the workpiece 3 is held in this manner, if the state detection unit 23 detects that there is a problem with the suction state of the workpiece 3, the suction control unit 22 replaces the suction pad 12 of one of the systems S1 and S3 with the suction pad 12 of the other system S1 and S3 to perform the suction operation, thereby maintaining the suction state of the workpiece 3. Note that when switching the system that performs the suction operation from system S1 to S3 or from system S3 to S1 in this manner, the operation control unit 21 needs to perform control such as shifting the position of the arm tip, that is, offsetting the position of the arm tip or rotating the arm tip 180 degrees, so that the suction pad 12 of the system after switching faces the workpiece 3 at an appropriate position.

The suction control unit 22 may be able to execute only one of the first control and the second control, or may be able to execute both the first control and the second control. When both the first control and the second control are executable, it is preferable to switch between the first control and the second control to be executed depending on the shape of the workpiece to be transported. Note that the first control and the second control can be executed only when at least one of the systems S1 to S3 is not performing the suction operation by the suction mechanism 11 and the inactive system can substitute for the system performing the suction operation.

When a transport operation is performed to transport multiple workpieces among workpieces 2, 3, and 4, the suction control unit 22 can suck and hold a specific workpiece using the suction mechanism 11 of one of systems S1 to S3, and then suck and hold a workpiece other than the specific work using the suction mechanism 11 of another system. Specific examples of control by the suction control unit 22 include the following. For example, when the workpieces to be transported are workpieces 2 and 3, the suction control unit 22 first sucks and holds workpiece 2 using the suction action of the suction pad 12 of system S2. Then, the suction control unit 22 sucks and holds workpiece 3 using the suction action of the suction pad 12 of system S1 or S3.

According to the present embodiment described above, the following effects can be obtained.
The suction control unit 22 divides the suction mechanisms 11a to 11e into three systems S1 to S3, and controls the operation of the suction mechanisms 11a to 11e independently for each of the three systems S1 to S3. When the transport operation is performed, the suction control unit 22 switches the system that performs the suction operation by the suction mechanism 11 according to the shape of the workpiece to be transported. According to the above configuration, when the workpiece to be transported is a relatively large workpiece 4 that cannot be sucked without using all the suction mechanisms 11, the workpiece 4 can be reliably sucked by performing the suction operation by the suction mechanisms of all the systems S1 to S3. In this case, since there is no suction mechanism 11 that does not contribute to the suction of the workpiece 4, air leakage does not occur as in the conventional configuration.

In addition, according to the above configuration, when the workpieces to be transported are relatively small workpieces 2 and 3 that can be sucked up only by a part of the suction mechanisms 11, the workpieces 2 and 3 can be sucked up by performing the suction operation by the suction mechanisms 11 of a part of the system used according to the shape of the workpieces 2 and 3. In this case, since the suction mechanisms 11 of the part of the system used are independent from the other suction mechanisms 11 that are not used, even if air leakage occurs in the suction mechanisms 11 of the other systems that are not used, the vacuum level in the suction mechanism 11 performing the suction operation does not decrease and the suction force does not weaken, and the workpieces 2 and 3 can be reliably sucked up. In this way, according to this embodiment, it is possible to obtain the excellent effect of reliably sucking up multiple types of workpieces with different shapes without increasing the size of the hand 10. Also, according to this embodiment, the air flow rate can be reduced to efficiently perform the transport operation.

In this embodiment, a state detection unit 23 is provided that detects whether there is a problem with the suction state of the workpieces 2 to 4 by the suction mechanism 11. In this case, when the state detection unit 23 detects that there is a problem with the suction state of the workpieces 2 to 4 during the transport operation, the suction control unit 22 can execute a first control to execute a suction operation by the suction mechanism 11 of a system other than the system that is currently executing the suction operation by the suction mechanism 11. According to this first control, if a problem such as a malfunction occurs in one of the suction mechanisms 11 of the system that initially executed the suction operation and the suction force weakens, the decrease in suction force is compensated for by additionally executing a suction operation by the suction mechanism 11 of the other system, and problems in the transport operation, such as the dropping of the workpieces 2 to 4, can be prevented.

In this case, when the state detection unit 23 detects that there is a problem with the suction state of the workpieces 2 to 4 during the transport operation, the suction control unit 22 can execute a second control to have the suction mechanism 11 of a system other than the system currently performing the suction operation by the suction mechanism 11 execute the suction operation. In this way, if a problem such as a malfunction occurs in one of the suction mechanisms 11 of the system that was initially performing the suction operation and the suction force weakens, the suction state of the workpieces 2 to 4 can be maintained by having the suction mechanism 11 of the other system execute the suction operation instead, and problems in the transport operation such as the dropping of the workpieces 2 to 4 can be prevented.

When a transport operation is performed to transport multiple workpieces 2 and 3, the suction control unit 22 first causes the suction mechanism 11 of one of the systems S2 among the systems S1 to S3 to suck and hold the workpiece 2, and then causes the suction mechanism 11 of the system S1 or S3 other than the system S2 to suck and hold the workpiece 3. In this way, multiple workpieces 2 and 3 can be sucked and held at once before being transported, so the amount of movement of the robot arm 8 is kept small, which results in an effect of shortening the time required for the transport operation.

In this embodiment, four suction pads 12a to 12d are arranged in a square shape, and one suction pad 12e is arranged at the center of the square. With this configuration, the load when suctioning the workpiece 4 can be evenly distributed to each suction pad 12 by performing the suction operation using all of the suction pads 12. In this case, the workpiece 4 is a bag containing multiple types of food such as oden, so it is heavy and soft, and there is a possibility that it will deform under its own weight. However, with the above configuration, it is possible to prevent deformation of the workpiece 4 when transporting it, and it can be reliably suctioned and transported.

Second Embodiment
The second embodiment will be described below with reference to FIGS.
The number of suction mechanisms, and therefore the number of suction pads, may be at least two. However, if there are only two suction pads, it may be difficult to accommodate the shape of the workpiece, so it is preferable that the number of suction pads is three or more.

[1] Example of the arrangement of suction pads when the number of suction mechanisms is three An example of the arrangement when the number of suction mechanisms and the number of suction pads are three can be, for example, the arrangement shown in Fig. 6. As shown in Fig. 6, the suction pads 32a, 32b, and 32c constituting the three suction mechanisms 31a, 31b, and 31c are arranged in a row so that the lines connecting their centers are linear. In this case, the distance between the center of the suction pad 32a and the center of the suction pad 32b and the distance between the center of the suction pad 32b and the center of the suction pad 32c are both the same. Note that when it is not necessary to distinguish between the suction mechanisms 31a to 31c and the suction pads 32a to 32c, the suffixes of the letters will be omitted and they will be referred to collectively.

In this case, the suction control unit 22 divides the opening and closing control of the air valves corresponding to the three suction mechanisms 31a to 31c into two systems S21 and S22, and controls the operation of the suction mechanisms 31a to 31c independently for each system S21 and S22. A specific example of switching between systems S21 and S22 by the suction control unit 22 will be described with reference to FIG. 7. Note that in FIG. 7, the rough outlines of the workpieces 33 and 34 are simply represented by lines.

The workpiece 33 has an outer shape that can be sucked by one suction pad 32. Therefore, when the transport target is the workpiece 33, the suction control unit 22 selects the system S21 as the system that will perform the suction operation by the suction mechanism 31, and sucks and holds the workpiece 33 by the suction operation by the suction pad 32 of the selected system S21. The workpiece 34 has an outer shape that can be sucked by three suction pads 32. Therefore, when the transport target is the workpiece 34, the suction control unit 22 selects the system S21 and the system S22 as the system that will perform the suction operation by the suction mechanism 31, and sucks and holds the workpiece 34 by the suction operation by the suction pad 32 of the selected systems S21 and S22.

[2] Example of Suction Pad Arrangement When the Number of Suction Mechanisms is Six An example of an arrangement when the number of suction mechanisms and suction pads is six is, for example, an arrangement as shown in Fig. 8. As shown in Fig. 8, suction pads 42a, 42b, 42c, 42d, 42e, and 42f constituting six suction mechanisms 41a, 41b, 41c, 41d, 41e, and 41f are arranged such that a line connecting their centers forms a rectangle.

In this case, the distance between the center of suction pad 42a and the center of suction pad 42b, the distance between the center of suction pad 42b and the center of suction pad 42c, the distance between the center of suction pad 42c and the center of suction pad 42d, the distance between the center of suction pad 42d and the center of suction pad 42e, the distance between the center of suction pad 42e and the center of suction pad 42f, and the distance between the center of suction pad 42f and the center of suction pad 42a are all the same. Note that when it is not necessary to distinguish between the suction mechanisms 41a to 41f and the suction pads 42a to 42f, the suffix letters will be omitted and they will be referred to collectively.

[3] Example of the arrangement of suction pads when the number of suction mechanisms is eight An example of the arrangement when the number of suction mechanisms and the number of suction pads are eight can be, for example, the arrangement shown in Fig. 9. As shown in Fig. 9, the suction pads 52a, 52b, 52e, and 52f constituting the four suction mechanisms 51a, 51b, 51e, and 51f are arranged so that the lines connecting their centers form a square. Therefore, the distance between the center of the suction pad 52a and the center of the suction pad 52b, the distance between the center of the suction pad 52b and the center of the suction pad 52e, the distance between the center of the suction pad 52e and the center of the suction pad 52f, and the distance between the center of the suction pad 52f and the center of the suction pad 52a are all the same.

The suction pads 52b, 52c, 52d, and 52e that make up the four suction mechanisms 51b, 51c, 51d, and 51e are arranged so that the lines connecting their centers form a square. Therefore, the distance between the center of suction pad 52b and the center of suction pad 52c, the distance between the center of suction pad 52c and the center of suction pad 52d, the distance between the center of suction pad 52d and the center of suction pad 52e, and the distance between the center of suction pad 52e and the center of suction pad 52b are all the same.

The suction pad 52g constituting the suction mechanism 51g is arranged so that its center is the point where a diagonal line connecting the center of the suction pad 52a and the center of the suction pad 52e intersects with a diagonal line connecting the center of the suction pad 52b and the center of the suction pad 52f. The suction pad 52h constituting the suction mechanism 51h is arranged so that its center is the point where a diagonal line connecting the center of the suction pad 52b and the center of the suction pad 52d intersects with a diagonal line connecting the center of the suction pad 52c and the center of the suction pad 52e.

As described above, the present embodiment, which has a different number of suction mechanisms and suction pads from the first embodiment, can achieve the same effects as the first embodiment. Note that, because the distance between each pad is equal in each configuration of the present embodiment described above, the load when suctioning the workpiece can be distributed to each suction pad 32, 42, 52 by performing the suction operation using all suction pads 32, 42, 52, so deformation of the workpiece can be prevented and the transport operation can be performed reliably.

Other Embodiments
The present invention is not limited to the embodiments described above and illustrated in the drawings, and can be modified, combined, or expanded in any manner without departing from the spirit and scope of the present invention.
The numerical values and the like shown in the above embodiments are merely examples and are not intended to be limiting.

The division of the systems by the suction control unit 22 can be further subdivided, and ultimately, it is possible to independently manage the air valves for each suction mechanism, and even for each suction pad. This allows for greater freedom in switching between systems according to the shape of the workpiece, resulting in greater versatility. In other words, this makes it possible to achieve suction that is appropriate for each workpiece, even when there are many different types of workpieces to be transported.

For example, if the opening and closing control of the air valves corresponding to the suction mechanisms 11a to 11e in the first embodiment is divided into five systems for each of the suction mechanisms 11a to 11e, in addition to the works 2 to 4, it will be possible to pick up three types of workpieces with different lengths, such as a workpiece whose length depends on factors such as the distance between suction pads 12a and 12b, a workpiece whose length depends on factors such as the distance between suction pads 12a and 12e, and a workpiece whose length depends on factors such as the distance between suction pads 12a and 12c. However, in this case, the operation control unit 21 needs to control the arm tip to rotate so that each suction pad 12 faces the workpiece at an appropriate position according to the workpiece to be picked up.

In addition, by dividing the opening and closing control of the air valves corresponding to each of the suction mechanisms 11a to 11e in the first embodiment into five systems for each of the suction mechanisms 11a to 11e, and positioning the suction pad 12e at a position shifted a specified distance from the center of the square, it becomes possible to adsorb workpieces of even different lengths, resulting in even greater versatility.

The suction control unit 22 can also use a suction mechanism that does not contribute to the suction of the workpiece as follows. That is, when placing the adsorbed workpiece in the container 5, the suction control unit 22 can control the suction pad of the suction mechanism that does not contribute to the suction of the workpiece to blow air. In this way, objects present around the placement location of the workpiece can be removed to ensure space for placing the workpiece. Specifically, if the workpiece is an egg, the egg can be placed by blowing away cushioning material such as sawdust that is spread in the container with air.

The present invention is not limited to a workpiece suction device including a suction mechanism attached to the hand 10 of the robot arm 8 applied to the production system 1, but can be applied to all workpiece suction devices that suck up workpieces transported by a robot arm.

2, 3, 4, 33, 34...workpiece, 8...robot arm, 10...hand, 11, 31, 41, 51...suction mechanism, 22...suction control unit, 23...status detection unit.

Claims (2)

a plurality of suction mechanisms attached to a hand of a robot arm that performs a transport operation of transporting a workpiece and that suck and hold the workpiece;
an adsorption control unit for controlling operations of the plurality of adsorption mechanisms;
Equipped with
The adsorption control unit is
the plurality of suction mechanisms are divided into a plurality of systems, and the operations of the plurality of suction mechanisms are controlled independently for each of the plurality of systems;
When the transport operation is performed, the system for performing the suction operation by the suction mechanism is switched according to the shape of the workpiece to be transported ;
Further, a state detection unit is provided for detecting whether or not there is a problem with the state of suction of the workpiece by the suction mechanism,
The suction control unit is a work suction device that, when the status detection unit detects a problem with the suction status of the workpiece during the transport operation, causes, in addition to the system that is currently performing the suction operation using the suction mechanism at that time, to perform the suction operation using the suction mechanism of a system other than the system . The adsorption control unit is
2. The work suction device according to claim 1, wherein, when the transport operation of transporting a plurality of the workpieces is performed, a predetermined workpiece is adsorbed and held by the suction mechanism of one of the plurality of systems, and then a workpiece other than the predetermined workpiece is adsorbed and held by the suction mechanism of a system other than that system.

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