JP2023080483A - pickup device - Google Patents

Abstract

To provide a pickup device that can reduce damage of a cable caused by motion of a robot, without designing the robot newly.SOLUTION: The pickup device comprises: a robot having a robot hand part; a cable connected to the robot from the outside of the robot; a first fixed part fixed to the cable, outside the robot; a second fixed part fixed to the cable, at a position farther away from the robot hand part than the first fixed part; and a tension applying mechanism that applies tension to a first cable portion through the first fixed part, where a second cable portion is maintained in a loosened state.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pickup device.

Due to the labor shortage in factories and the like, there is an increasing demand for pick-up devices that use robots to pick up parts. Moreover, in recent years, in order to realize automatic assembly of a wide variety of parts, robots are required to perform a wide range of operations and are complex.

A robot used in the pick-up device has a robot hand for picking and placing parts. Also, the robot is connected to a cable for driving a motor for a robot hand, for example. The cables should be laid out so that the movement of the robot does not damage the cables or adversely affect the movement of the robot due to the existence of the cables. Patent Literature 1 describes a technology related to an articulated welding robot in which a cable is laid inside a robot arm.

JP 2018-122405 A

However, with the technique described in Patent Document 1, it is necessary to design a new robot in order to change the structure of the robot arm in accordance with the cable layout, which increases costs.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pick-up device capable of reducing damage to the cable caused by the operation of the robot without newly designing the robot.

A pick-up device according to the present invention includes a robot having a robot hand, a cable connected to the robot from the outside of the robot, a first fixing part fixed to the cable outside the robot, and a robot hand attached to the robot rather than the first fixing part. a second fixing part fixed to the cable at a position separated from the hand part; and a tension applying mechanism applying tension to the first cable part between the robot hand part and the first fixing part via the first fixing part. , wherein the second cable portion between the first and second securing portions is maintained in a slack condition.

According to the present invention, it is possible to reduce damage to the cable caused by the operation of the robot without newly designing the robot.

1 is a schematic side view showing the configuration of a pickup device according to a first embodiment of the present invention; FIG. 1 is a schematic front view showing the configuration of a pickup device according to a first embodiment of the present invention; FIG. It is a perspective view which shows the structural example of a robot hand part. It is a figure which shows the structural example of a cable. It is the figure which expanded the 1st fixing|fixed part. It is a figure which shows the structural example of a 1st cable cover fixing tool. It is the figure which expanded the 2nd fixing|fixed part. 3 is a block diagram showing the configuration of a robot control system in the pick-up device; FIG. 4 is a flowchart showing a procedure of robot control processing; FIG. 5 is a schematic diagram showing the configuration of a pickup device according to a second embodiment of the present invention;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present specification and drawings, constituent elements having substantially the same function or configuration are denoted by the same reference numerals, and overlapping descriptions are omitted.

<First embodiment>
FIG. 1 is a schematic side view showing the configuration of the pickup device according to the first embodiment of the invention, and FIG. 2 is a schematic front view showing the configuration of the pickup device according to the first embodiment of the invention.
As shown in FIGS. 1 and 2, the pickup device 10 includes a robot 12, a cable 14, a first fixing portion 16, a second fixing portion 18, and a tensioning mechanism 20. As shown in FIG.

The robot 12 is configured by a multi-axis robot. In this embodiment, as an example, the robot 12 is a six-axis robot. The robot 12 is a so-called robot arm having a waist portion 21 , a lower arm portion 22 , an upper arm portion 24 and a wrist portion 26 . A robot hand section 28 is attached to a wrist section 26 positioned at the tip of the robot arm. The robot hand section 28 is arranged downward. The robot hand unit 28 has a function of picking and placing parts (not shown). The robot hand unit 28 moves within a robot motion range 15 defined by a three-dimensional space (XYZ space). The robot operating range 15 is the range in which the robot hand section 28 moves to pick and place parts. The robot operating range 15 is determined by the working conditions of the robot 12, such as the size and shape of the part, the position for picking the part, and the position for placing the part. In addition, the motion range of the wrist portion 26 is set to ±180 degrees, and the joint coordinate transformation is performed from the orthogonal coordinates from the motion start position to the motion completion position by the inverse equation of motion, so that the robot is within the above motion range. A moving route of the hand part 28 is determined.

FIG. 3 is a perspective view showing a configuration example of a robot hand unit.
As shown in FIG. 3, the robot hand section 28 has a pair of grippers 30, a camera 32, a lighting device 34, a robot hand motor, and various sensors (not shown). Various sensors include, for example, displacement sensors, grip force sensors, proximity sensors, and the like.

A pair of grippers 30 function as two fingers in the robot hand section 28 . The pair of grippers 30 are provided so as to be movable toward or away from each other, that is, open and close. The pair of grippers 30 are opened and closed according to the drive of the robot hand motor. The pair of grippers 30 has a function of gripping a part for picking the part and releasing the grip of the part for placing the part. Camera 32 is a camera for recognizing an object. Objects recognized by the camera 32 include parts to be picked and placed. The lighting device 34 is a device that irradiates the imaging area of the camera 32 with light. The lighting device 34 is configured by, for example, an LED lighting device using an LED (light emitting diode) as a light source.

In the following description, the mounting surface 12a of the robot 12 is defined as a horizontal reference plane, and orthogonal two axial directions parallel to this horizontal reference plane are defined as the X direction and the Y direction. A direction orthogonal to the X direction and the Y direction is defined as the Z direction. The X and Y directions are parallel to the horizontal direction, and the Z direction is parallel to the vertical direction.

A cable 14 is connected to the robot 12 from outside the robot 12 as shown in FIGS. By connecting the cable 14 to the robot 12 in this manner, the need for a new robot design to run the cable inside the robot arm is eliminated. Therefore, existing robots including general-purpose robots can be used as the robot 12 .

The cable 14 is connected to the robot 12 from the opposite side of the robot hand section 28 . In this embodiment, since the robot hand portion 28 is arranged facing downward, the cable 14 is connected to the robot 12 from the opposite side of the robot hand portion 28, that is, from above. One end 14 a of the cable 14 is connected to the robot hand section 28 from above the robot 12 . By connecting the cable 14 to the robot 12 in this way, the cable 14 is less likely to interfere with the upper arm portion 24 and the robot hand portion 28 of the robot 12 during operation of the robot 12 .

In addition, the robot hand unit 28 is not limited to being arranged downward, and may be arranged upward. In that case, the cable 14 would be connected to the robot 12 from below.

The cable 14 has three cable wirings 36 and a cable cover 38 enclosing these cable wirings 36, as shown in FIG. One end of the cable wiring 36 is electrically connected to the robot hand motor, the camera 32, the lighting device 34, etc., which are electronic devices mounted on the robot hand unit 28, and the other end of the cable wiring 36 is connected to a power supply (not shown), It is electrically connected to a driving board, an image processing board, and the like. The number of cable wirings 36 is determined according to the number of electronic devices mounted on the robot hand unit 28 and the like. Therefore, the number of cable wirings 36 is not limited to three, and may be two or less, or may be four or more. The cable cover 38 has a function of bundling a plurality of cable wirings 36 and a function of protecting the cable wirings 36 . The cable cover 38 is made of resin such as polyamide, nylon 6, polypropylene, or the like. Moreover, the cable cover 38 is preferably made of a corrugated tube having moderate flexibility.

As a method for determining the size of the cable cover 38, the cable space factor is determined based on the inner diameter of the cable cover 38 and the total cross-sectional area of each cable wiring 36, and the value of the cable space factor is set to a reference value or less. There is a way to decide Moreover, in order to prevent the connector portion from entering inside the cable cover 38, it is preferable to fix each cable wiring 36 to the cable cover 38 at both ends of the cable cover 38. FIG. Each cable wiring 36 is preferably highly flexible. Moreover, it is preferable to determine the fixed position of the cable cover 38 in consideration of the bending radius of the cable wiring 36 . Cable covers 38 need not be all-in-one. For example, one cable cover 38 may be used from the robot hand portion 28 to the second fixed portion 18, and a different cable cover may be used from the second fixed portion 18 forward. In addition, if the portion from the second fixing portion 18 onward is configured with a cable cover having a half-split structure, replacement of the cable wiring 36 and the like is facilitated.

Note that the cable 14 may not have the cable cover 38 . In this case, the cable 14 is in a so-called bundle state in which a predetermined number of cable wirings 36 are bundled together.

Returning to FIGS. 1 and 2 again, the first fixed part 16 is fixed to the cable 14 outside the robot 12 and the second fixed part 18 is also fixed to the cable 14 outside the robot 12 . Both the first fixed part 16 and the second fixed part 18 are arranged outside the robot motion range 15 . Both the first fixing portion 16 and the second fixing portion 18 are fixed to the cable cover 38 . The cable length from the robot hand portion 28 to the first fixing portion 16 is shorter than the cable length from the robot hand portion 28 to the second fixing portion 18 . That is, the second fixing portion 18 is fixed to the cable 14 at a position farther from the robot hand portion 28 than the first fixing portion 16 is. In this specification, the cable 14 portion between the robot hand portion 28 and the first fixed portion 16 is defined as the first cable portion 41, and the cable 14 portion between the first fixed portion 16 and the second fixed portion 18 is defined as the first cable portion 41. A section is defined as a second cable section 42 .

The tension applying mechanism 20 is a mechanism that applies tension to the first cable portion 41 via the first fixing portion 16 . The tension applying mechanism 20 is arranged outside the robot motion range 15 . The first cable portion 41 is maintained under tension by the tensioning mechanism 20 during operation of the robot 12 . In contrast, the second cable portion 42 remains slack during operation of the robot 12 . The slack amount of the second cable portion 42 is set so that the second cable portion 42 is arranged outside the robot motion range 15 even when the second cable portion 42 is most slack during motion of the robot 12 . That is, the second cable portion 42 is always slack and positioned outside the robot motion range 15 during motion of the robot 12 .

The length of the cable from the robot hand portion 28 to the first fixing portion 16, that is, the length of the first cable portion 41, is determined at the position where the robot hand portion 28 is farthest from the body portion 20a of the tension applying mechanism 20 within the robot operation range 15. and the closest position, the tension applying mechanism 20 can apply tension to the first cable portion 41. That is, the first cable portion 41 is always kept under tension during operation of the robot 12 .

The tensioning mechanism 20 is composed of, for example, a spring balancer. A spring balancer is a device that applies tension using the tension of a spring. The tension applying mechanism 20 includes a body portion 20a that accommodates a rotating drum and a spring (not shown), and an extendable wire 20b. The wire 20b is wound around a rotating drum within the body portion 20a. The spring imparts torque to the rotating drum for winding the wire 20b. Note that the tension applying mechanism 20 is not limited to a spring balancer.

The tension applying mechanism 20 is attached to the safety fence 45 . The safety fence 45 is installed at a suitable distance from the robot motion range 15 so that the worker does not come into contact with the robot 12 while the robot 12 is in motion. The safety fence 45 is configured by appropriately combining a vertical frame 45a installed vertically and a horizontal frame 45b installed horizontally. A hook (not shown) is attached to the upper portion of the main body 20a of the tension applying mechanism 20, and the main body 20a of the tension applying mechanism 20 is suspended from the horizontal frame 45b using this hook. Here, the position of the tension applying mechanism 20 (body portion 20 a ) in the horizontal direction is in the vicinity of the central position of the robot motion range 15 . In other words, the body portion 20 a of the tension applying mechanism 20 is arranged near the center position of the robot motion range 15 . As a result, variations (fluctuations) in the tension applied to the first cable portion 41 by the tension applying mechanism 20 can be minimized.

On the other hand, the tip of the wire 20b pulled out from the main body 20a of the tension applying mechanism 20 is connected to the first fixing portion 16. As shown in FIG. The wire 20b applies tension to the first cable portion 41 in a direction to pull the first fixing portion 16 toward the main body portion 20a. The strength of the tension applied to the first cable portion 41 by the tension applying mechanism 20 is appropriately set according to the weight and flexibility of the cable 14 within a range in which an excessive load is not applied to the cable 14 . The tension applying mechanism 20 applies substantially constant tension to the first cable portion 41 based on the operating principle of the spring balancer, regardless of the amount of expansion or contraction of the wire 20b. Therefore, while the robot 12 is operating, the direction and the amount of expansion/contraction of the wire 20b change according to the displacement of the robot hand portion 28, but the tension applied to the first cable portion 41 by the tension applying mechanism 20 is substantially constant. maintained at

FIG. 5 is an enlarged view of the first fixing portion.
As shown in FIG. 5 , the first fixing portion 16 is configured by a first cable cover fixture 51 . The first cable cover fixture 51, as shown in FIG. 6, has a gripping member 51a and a pressing member 51b. The gripping member 51 a is a member that grips the cable cover 38 . The pressing member 51 b is a member that presses the cable cover 38 . The pressing member 51b is detachably attached to the gripping member 51a. When fixing the first cable cover fixture 51 to the cable cover 38, first, the cable cover 38 is fitted into the gripping member 51a, and then the pressing member 51b is attached to the gripping member 51a. Thereby, the first cable cover fixture 51 is fixed to the cable cover 38 .

On the other hand, the first fixing portion 16 and the tension applying mechanism 20 are connected by a joint portion 55 as shown in FIG. The joint portion 55 includes a pair of joint members 55a and 55b, a connecting shaft portion 55c that rotatably connects the pair of joint members 55a and 55b, a connecting stud 55d detachably attached to one joint member 55a, and a connection stud 55e detachably attached to the other joint member 55b. In contrast, the first cable cover fixture 51 has a bracket 51c. The bracket 51c is fixed to the gripping member 51a by screwing or the like. Further, the bracket 51c is provided with a connecting hole 51d.

When the first fixing portion 16 and the tension applying mechanism 20 are connected by the joint portion 55, the connection stud 55d removed from the joint member 55a is inserted into the hole 51d of the bracket 51c and attached to the joint member 55a. Thereby, the joint member 55a is connected to the first cable cover fixture 51 . On the other hand, as for the tension applying mechanism 20, the tip of the wire 20b is attached to the connecting stud 55e. Since a hook or carabiner (not shown) is attached to the tip of the wire 20b, the hook or carabiner is hooked on the connecting stud 55e. By rotatably connecting the first fixing portion 16 and the tension applying mechanism 20 by the joint portion 55 in this manner, twisting of the wire 20b is suppressed during operation of the robot 12, and the tension applying mechanism 20 (main body portion 20a) is prevented from twisting. ) can be reduced.

FIG. 7 is an enlarged view of the second fixing portion.
As shown in FIG. 7 , the second fixing portion 18 is configured by a second cable cover fixture 52 . The second cable cover fixture 52 is fixed to the vertical frame 45a of the safety fence 45 by screws or the like. The second cable cover fixture 52 fixes the cable cover 38 while gripping the cable cover 38 . The second cable cover fixture 52 may have the same structure as the first cable cover fixture 51 (FIG. 6). Further, as shown in FIG. 3, when the portion for fixing one end 14a of the cable 14 to the robot hand portion 28 is the third fixing portion 19, the third fixing portion 19 is secured by the third cable cover fixture 53. may be configured. The third cable cover fixture 53 may have the same structure as the first cable cover fixture 51 .

FIG. 8 is a block diagram showing the configuration of the robot control system in the pick-up device.
In FIG. 8 , a control unit 60 is a robot controller that controls the motion of the robot 12 . The control unit 60 is electrically connected to six motors 61, 62, 63, 64, 65, 66. Six motors 61 to 66 are drive sources for operating the robot 12, which is a six-axis robot. The control unit 60 supplies motor currents to the motors 61, 62, 63, 64, 65, 66, respectively. Also, the control unit 60 monitors the motor current supplied to each motor 61, 62, 63, 64, 65, 66. FIG. In addition, the control unit 60 limits the rotation angles of the wrist unit 26 and the robot hand unit 28 to within a predetermined range so as not to apply an excessive load to the cable 14 (especially the first cable portion 41) during operation of the robot 12. do.

FIG. 9 is a flowchart showing the procedure of robot control processing.
First, the control unit 60 causes the robot 12 to perform a pick-and-place operation by supplying motor currents to the motors 61, 62, 63, 64, 65, and 66 (step S1).

Next, the controller 60 monitors motor currents supplied to the motors 61, 62, 63, 64, 65 and 66 (step S2). The motor current corresponds to the load applied to the tensioning mechanism 20 during operation of the robot 12 . The reason is as follows. If, for example, the tensioning mechanism 20 is damaged during operation of the robot 12 and the wire 20b is locked, the wire 20b is strongly stretched and the load applied to the tensioning mechanism 20 is increased. Also, when the wire 20b is stretched strongly, the load applied to the robot 12 also increases, so the motor current supplied to each motor 61, 62, 63, 64, 65, 66 increases. Therefore, the magnitude of the load applied to the tension applying mechanism 20 can be detected from the motor current. Note that the load applied to the tensioning mechanism 20 may be detected by parameters other than the motor current.

Next, the control unit 60 determines whether any of the motor currents supplied to the motors 61, 62, 63, 64, 65, and 66 has exceeded a predetermined threshold value. (step S3). The case where the motor current value exceeds the threshold value corresponds to the case where a load equal to or greater than a predetermined value is applied to the tensioning mechanism 20 during operation of the robot 12 . The threshold should be set to a value that does not apply an excessive load to the cable 14 . Also, the threshold value may be set for each motor according to the specifications of each motor 61 , 62 , 63 , 64 , 65 , 66 .

If the motor currents supplied to the motors 61, 62, 63, 64, 65, and 66 are all less than the threshold value (No in step S3), the controller 60 proceeds to step S4.

Next, in step S4, the control section 60 determines whether or not the pick-and-place of all parts has been completed. Then, if the pick-and-place of all parts has not been completed (No in step S4), the control unit 60 returns to step S1 and allows the robot 12 to continue the pick-and-place operation. Further, when the pick-and-place of all parts is completed (Yes in step S4), the control unit 60 ends the series of processes at that point.

Further, if the value of any one of the motor currents supplied to the motors 61, 62, 63, 64, 65, and 66 is equal to or greater than the threshold value (Yes in step S3), the control unit 60 case), the operation of the robot 12 is immediately stopped (step S5), and the series of processes is finished. At this time, the control unit 60 may perform processing for notifying the operator that the operation of the robot 12 has been stopped (emergency stop) because a load of a predetermined value or more has been applied to the tension applying mechanism 20. Examples of the notification process include a process of emitting an alarm sound, a process of lighting or blinking a warning light, and a process of transmitting alarm information to the mobile terminal of the worker.

Thus, by stopping the operation of the robot 12 when the motor current value exceeds the threshold during operation of the robot 12, an excessive load is applied to the cable 14 due to breakage of the tension applying mechanism 20 or the like. can be prevented from occurring.

As explained above, in the first embodiment of the present invention, the cable 14 is connected to the robot 12 from the outside of the robot 12 . Therefore, it is not necessary to newly design the robot 12 according to the layout of the cable 14 . That is, the robot 12 may be an existing robot including general-purpose robots. In addition, in the first embodiment of the present invention, tension is applied to the first cable portion 41 near the robot hand portion 28 by the tension applying mechanism 20 via the first fixing portion 16, and tension is applied to the first cable portion 41 far from the robot hand portion 28. 2 The cable portion 42 is given some slack. As a result, the cable 14 is less likely to interfere with the robot 12 and surrounding articles during operation of the robot 12, and excessive force is less likely to be applied to the cable 14. - 特許庁Therefore, damage to the cable 14 caused by the operation of the robot 12 can be reduced. Therefore, according to the first embodiment of the present invention, the robot 12 can be used for a long period of time while suppressing damage to the cable 14, and the low-cost and highly versatile pickup device 10 can be realized.

Moreover, in the first embodiment of the present invention, both the first fixing portion 16 and the second fixing portion 18 are arranged outside the robot motion range 15 . Thereby, it is possible to prevent the robot hand portion 28 from interfering with the first fixing portion 16 and the second fixing portion 18 during operation of the robot 12 .

Also, in the first embodiment of the present invention, the second cable portion 42 is arranged outside the robot motion range 15 . Thereby, it is possible to prevent the robot hand portion 28 from interfering with the second cable portion 42 during operation of the robot 12 .

<Second embodiment>
FIG. 10 is a schematic diagram showing the configuration of a pickup device according to the second embodiment of the present invention.
In the pickup device 10A according to the second embodiment, a robot 12 is provided so as to be movable in the horizontal direction H. As shown in FIG. Also, the tension applying mechanism 20 and the second fixing portion 18 are attached to the support member 70 . The support member 70 is movably attached to a guide rail 72 . The guide rail 72 is arranged above the robot 12 in a direction parallel to the horizontal direction H, which is the movement direction of the robot 12 . As in the first embodiment, the first fixing portion 16, the second fixing portion 18, the tension applying mechanism 20, and the second cable portion 42 are arranged outside the robot motion range 15. FIG.

In the pickup device 10A having the above configuration, the support member 70 moves along the guide rail 72 when the robot 12 moves in the horizontal direction H. As shown in FIG. Therefore, the tension applying mechanism 20 and the second fixing portion 18 attached to the support member 70 move in the horizontal direction H so as to follow the movement of the robot 12 . As a result, even when the robot 12 moves, the load applied to the cable 14 can be suppressed and damage to the cable 14 can be reduced.

<Modifications, etc.>
The technical scope of the present invention is not limited to the above-described embodiments, and various modifications and improvements can be made within the scope of achieving specific effects obtained by the constituent elements of the invention or the combination of the constituent elements. Also includes

For example, in the above embodiment, the case where the robot 12 is a 6-axis robot has been described as an example, but the present invention is not limited to this, and a robot other than a 6-axis robot may be used.

DESCRIPTION OF SYMBOLS 10... Pick-up apparatus 12... Robot 14... Cable 15... Robot motion range 16... First fixed part 18... Second fixed part 20... Tension applying mechanism 28... Robot hand part 32... Camera 34... Lighting device 36... Cable wiring 38... Cable cover 41 First cable portion 42 Second cable portion 51 First cable cover fixture 52 Second cable cover fixture 55 Joint section 60 Control section

Claims (14)

a robot having a robot hand;
a cable connected to the robot from outside the robot;
a first fixing part fixed to the cable outside the robot;
a second fixing portion fixed to the cable at a position farther from the robot hand than the first fixing portion;
a tension applying mechanism that applies tension to a first cable portion between the robot hand portion and the first fixing portion via the first fixing portion;
with
A pick-up device in which a second cable portion between the first fixing portion and the second fixing portion is maintained in a slack state. 2. The pick-up device according to claim 1, wherein each of said first fixed part and said second fixed part is arranged outside a robot motion range. 3. A pick-up device according to claim 1 or 2, wherein the second cable portion is arranged outside the robot operating range. The pickup device according to any one of claims 1 to 3, wherein the position of the tension applying mechanism in the horizontal direction is in the vicinity of the central position of the robot motion range. The pickup device according to any one of claims 1 to 4, further comprising a joint portion that rotatably connects the first fixing portion and the tension applying mechanism. The cable has a predetermined number of cable wirings and a cable cover that encloses the cable wirings,
The pickup device according to any one of claims 1 to 5, wherein each of said first fixing portion and said second fixing portion is fixed to said cable cover. 7. The cable cover according to claim 6, wherein a first cable cover fixing member forming the first fixing portion and a second cable cover fixing member forming the second fixing portion are fixed to the cable cover. pickup device. The pickup device according to any one of claims 1 to 7, wherein the cable is connected to the robot from a side opposite to the direction of the robot hand section. The pickup device according to any one of claims 1 to 8, wherein one end of the cable is connected to the robot hand section. The pickup apparatus according to any one of claims 1 to 9, further comprising a control section that stops the operation of the robot when a load equal to or greater than a predetermined value is applied to the tensioning mechanism during operation of the robot. The robot is movably provided,
The pickup device according to any one of claims 1 to 10, wherein the tension applying mechanism and the second fixing section are movable so as to follow the movement of the robot. The pickup device according to any one of claims 1 to 11, wherein the tension applying mechanism is configured by a spring balancer. The pickup device according to any one of claims 1 to 12, wherein the cable has cable wiring connected to an electronic device mounted on the robot hand section. 14. The pickup device according to claim 13, wherein the electronic device includes at least one of a robot hand motor, a camera, and a lighting device.

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