JP6872910B2 - Cloth piece gripping device and cloth piece gripping method - Google Patents

Description

The present invention relates to a cloth piece gripping device for gripping cloth such as hand towels and towels, and a cloth piece gripping method.

In the so-called linen supply industry, we supply towels, sheets, and other cloth pieces to hotels, restaurants, medical facilities, and so on. Many pieces of cloth collected from the business partner are washed, dried, and re-supplied to the business partner in a folded state for each piece of cloth. This piece of cloth is a hand towel, towel, sheet, or the like having various sizes, and is often in a rectangular shape such as a square or a rectangle.

A device for automation has been introduced in a series of work processes in which a large number of cloth pieces are washed, dried, and folded. However, automation does not cover the entire process with a single device, but is often divided into a washing device, a drying device, a folding device, and the like in terms of cost and compactness.

Further, between each of the above steps, an operator who delivers the cloth piece from the device for each process to the device for the next process often intervenes. In particular, because of the process of folding each piece of cloth, it may be necessary to unfold each piece of cloth in a rolled or overlapped state and align it in a certain direction.

Therefore, the applicant has developed a device that automatically detects the edge of the suspended cloth piece (see, for example, Patent Document 1). By using this device, the edge portion of the cloth piece can be detected, and the cloth piece can be spread by grasping the edge portion.

Japanese Unexamined Patent Publication No. 2014-45801

However, when trying to grip the two detected edges, if the two gripping devices are too close to each other, they may interfere with each other and collide with each other.

An object of the present invention is to provide a cloth piece gripping device and a cloth piece gripping method capable of gripping a cloth piece by confirming whether or not they interfere with each other when gripping two corners (edges) of the cloth piece.

The cloth piece gripping device according to the present invention includes a three-dimensional measuring device that measures the three-dimensional shape of a suspended cloth piece.
Based on the measured three-dimensional shape of the cloth piece, a gripping determination unit that recognizes two adjacent corners of the cloth piece and determines whether the two corners can be gripped.
A pair of gripping hands that grip the two corners of the cloth piece, respectively.
To be equipped.

The cloth piece gripping method according to the present invention includes a step of acquiring a three-dimensional shape of the cloth piece and
The step of recognizing the two corners of the cloth piece,
A step of determining whether the two corners of the cloth piece can be gripped substantially at the same time,
A step of gripping the two corners of the cloth piece with a pair of gripping hands,
including.

According to the cloth piece gripping device and the cloth piece gripping method according to the present invention, when gripping the two corners of the cloth piece, it is possible to check whether they interfere with each other and grip the cloth piece.

It is a block diagram which shows the structure of the cloth piece gripping apparatus which concerns on Embodiment 1. FIG. It is a schematic perspective view which shows the schematic structure of the example of the cloth piece gripping apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the physical structure and the functional structure of the gripping determination part of the cloth piece gripping apparatus which concerns on Embodiment 1. FIG. It is a flowchart of the cloth piece grasping method which concerns on Embodiment 1. FIG. It is a flowchart which shows the detail of the acquisition step of the three-dimensional shape of the cloth piece of FIG. It is a flowchart which shows the detail of the recognition step of the two corners of the cloth piece of FIG.

The cloth piece gripping device according to the first aspect includes a three-dimensional measuring device that measures the three-dimensional shape of the suspended cloth piece.
Based on the measured three-dimensional shape of the cloth piece, a gripping determination unit that recognizes two adjacent corners of the cloth piece and determines whether the two corners can be gripped.
A pair of gripping hands that grip the two corners of the cloth piece, respectively.
To be equipped.

The cloth piece gripping device according to the second aspect is the three-dimensional measuring device in the first aspect.
A three-dimensional camera that shoots from vertically below the piece of cloth,
A three-dimensional shape calculation unit that acquires the three-dimensional shape of the cloth piece based on the image taken by the three-dimensional camera, and
May be provided.

In the cloth piece gripping device according to the third aspect, in the first or second aspect, the gripping determination unit is
A corner recognition unit that recognizes two adjacent corners of the cloth piece based on the three-dimensional shape of the cloth piece, and a corner recognition unit.
A gripping possibility determination unit for determining whether the two corners can be gripped substantially at the same time,
May be provided.

In the cloth piece gripping device according to the fourth aspect, in the third aspect, the corner recognition unit detects the lowest point vertically below the measured three-dimensional shape of the cloth piece, and at the same time, the lowest point is detected. Both ends of the line extending in both directions from the lower point may be recognized as corners.

In the cloth piece gripping device according to the fifth aspect, in the third or fourth aspect, when the gripping possibility determination unit grips the two corners substantially simultaneously with the pair of gripping hands. In addition, it may be calculated whether or not the pair of gripping hands physically interfere with each other, and it may be determined whether or not the two corners can be gripped substantially at the same time.

The cloth piece gripping device according to the sixth aspect is a position in which the pair of gripping hands can grip the two corners recognized by the gripping determination unit in any one of the first to fifth aspects. Each may be movable.

The cloth piece gripping device according to the seventh aspect may further include a cloth piece hanging portion for suspending the cloth piece in any one of the first to sixth aspects.

The cloth piece gripping device according to the eighth aspect may further include a sub camera for detecting the suspended cloth piece in any one of the first to sixth aspects.

The cloth piece gripping method according to the ninth aspect includes a step of acquiring a three-dimensional shape of the cloth piece and
The step of recognizing the two corners of the cloth piece,
A step of determining whether the two corners of the cloth piece can be gripped substantially at the same time,
A step of gripping the two corners of the cloth piece with a pair of gripping hands,
including.

In the cloth piece gripping method according to the tenth aspect, in the ninth aspect, the step of acquiring the three-dimensional shape of the cloth piece is
The step of obtaining an image by taking a picture with a camera from vertically below the piece of cloth,
A step of acquiring the three-dimensional shape of the cloth piece based on the captured image, and
May include.

In the cloth piece gripping method according to the eleventh aspect, in the ninth or tenth aspect, the step of recognizing the two corners of the cloth piece is
A step of detecting the lowest point vertically below the three-dimensional shape of the cloth piece, and
A step of recognizing both ends of a line extending in both directions from the lowest point as corners,
May include.

In the cloth piece gripping method according to the twelfth aspect, in any one of the ninth to eleventh aspects, the step of determining whether the two corners of the cloth piece can be gripped substantially at the same time is the step of determining the two corners. Depending on whether the distance between the portions is equal to or greater than a predetermined value, it may be determined whether the two corner portions can be gripped substantially at the same time.

Hereinafter, the cloth piece gripping device and the cloth piece gripping method according to the embodiment will be described with reference to the accompanying drawings. In the drawings, substantially the same members are designated by the same reference numerals.

(Embodiment 1)
<Cloth piece gripping device>
FIG. 1 is a block diagram showing a configuration of the cloth piece gripping device 20 according to the first embodiment. FIG. 2 is a schematic perspective view showing a schematic configuration of an example of the cloth piece gripping device 20 according to the first embodiment.
The cloth piece gripping device 20 includes a three-dimensional measuring device 11, a gripping determination unit 14, and a pair of gripping hands 18a and 18b. The three-dimensional shape of the cloth piece 22 suspended by the three-dimensional measuring device 11 is measured. Based on the measured three-dimensional shape of the cloth piece 22, the gripping determination unit 14 recognizes the two adjacent corners 26a and 26b of the cloth piece 22 and determines whether the two corners 26a and 26b can be gripped. To do. The pair of gripping hands 18a and 18b grip the two corners 26a and 26b of the cloth piece 22, respectively. Further, a cloth piece hanging portion 17 for suspending the cloth piece 22 may be provided. Alternatively, a sub camera 19 that detects the cloth piece 22 suspended from the cloth piece hanging portion 17 may be provided. Further, a control unit 10 that controls the whole may be provided.

As described above, the cloth piece gripping device 20 recognizes the two adjacent corners 26a and 26b of the cloth piece 22 based on the measured three-dimensional shape of the cloth piece 22, and the two corners 26a. , 26b is provided with a gripping determination unit 14 for determining whether or not 26b can be gripped. Therefore, when gripping the two corners 26a and 26b of the cloth piece 22, it is possible to check whether the cloth pieces 22 interfere with each other and grip the cloth piece 22.

Each component constituting the cloth piece gripping device 20 will be described below.

<Cloth piece>
The cloth piece 22 to be gripped here is not particularly limited, but is, for example, a cloth piece having a rectangular shape such as a hand towel, a face towel, a washcloth, a bath towel, a towel, sheets, a pillow cover, and a table cloth. Good.

<Cloth piece hanging part>
The cloth piece 22 is suspended by the cloth piece hanging portion 17. The cloth piece hanging portion 17 may be held in a state where at least a part of the cloth piece 22 is hung down. For example, a conveyor for transporting the cloth piece 22 or a part of the cloth piece 22 is gripped and hung. It may be a robot hand, a hanging tool for hooking the cloth piece 22, a hook, or the like. When the cloth piece hanging portion 17 is a conveyor, the cloth piece 22 is conveyed on the conveyor 17 as shown in FIG. When the vertically lower side 23 of the cloth piece 22 hangs down from the conveyor 17 and protrudes, the cloth piece 22 can be detected by the sub camera 19 described later. When the cloth piece 22 is detected from the cloth piece hanging portion 17, the conveyor 17 is stopped.
If the two corners of the cloth piece 22 cannot be recognized, or if the distance between the two corners 26a and 26b is less than a predetermined value, the cloth piece 22 is discharged because it cannot be gripped (S09). For example, the conveyor 17 may be operated to drop the cloth piece 22 from the conveyor 17. In this case as well, the cloth piece 22 may be collected and conveyed again on the conveyor 17 to be gripped again.

<Three-dimensional measuring device>
The three-dimensional measuring device 11 acquires the three-dimensional shape of the cloth piece 22 based on the three-dimensional camera 12 that captures the vertically lower side 23 of the cloth piece 22 and the image taken by the three-dimensional camera 12. A calculation unit 13 is provided. The method of acquiring the three-dimensional shape by the three-dimensional shape calculation unit 13 can be used as long as it is a generally used technique. For example, a method of shooting with a stereo camera, a light cutting method of irradiating line light, a phase shift method of acquiring a three-dimensional shape from a plurality of images projected with a lattice pattern whose phase is slightly shifted, and ToF (Time). The of Flight) method or other method of scanning with a laser displacement meter may be used.
In order to grip the two corners 26a and 26b of the vertically lower side 23 of the cloth piece 22, the three-dimensional shape including the corners 26a and 26b of the cloth piece 22 is measured. Since the cloth pieces 22 may be hung in a folded state, the more oblique the shooting direction is with respect to the vertically downward direction, the more likely it is that occlusion of the corners will occur. Therefore, in order to reliably measure the two corners 26a and 26b, it is preferable to photograph the cloth piece 22 from vertically below.

<Gripping judgment unit>
FIG. 3 is a block diagram showing a physical configuration and a functional configuration of the grip determination unit 14 of the cloth piece gripping device 20 according to the first embodiment.
As a physical configuration of the grip determination unit 14, as shown in the block diagram of FIG. 3, physical components of a normal personal computer, for example, a CPU 1, a memory 2, a storage unit 3, a display unit 4, and an input unit It suffices to have 5, interface 6, and the like.

Further, as a functional configuration of the grip determination unit 14, a corner portion recognition unit 15 and a gripability determination unit 16 are provided.
The corner recognition unit 15 recognizes two adjacent corners 26a and 26b of the cloth piece 22 based on the measured three-dimensional shape of the cloth piece 22. Specifically, the lowest point 24 vertically below the three-dimensional shape of the cloth piece 22 is detected, and both ends of the line 23 extending in both directions from the lowest point 24 are recognized as corners 26a and 26b, respectively. .. When the line 23 extends vertically upward from the lowest point 24, or when the angle formed by the line 23 extending in both directions from the lowest point 24 is approximately right angle, the lowest point 24 itself is a corner portion. May be considered. In this case, it suffices that at least one of both ends of the line 23 extending in both directions from the lowest point 24 other than the lowest point 24 can be recognized as a corner portion. If the two corners of the cloth piece 22 cannot be recognized, it is determined that the corners that can be gripped cannot be confirmed, the cloth piece 22 is discharged, and the next cloth piece is hung.

The gripping possibility determination unit 16 determines whether the two corner portions 26a and 26b can be gripped substantially at the same time. Specifically, when the pair of gripping hands 18a and 18b grip the two corners 26a and 26b substantially at the same time, whether or not the pair of gripping hands 18a and 18b physically interfere with each other. Is calculated. That is, it is determined whether or not the distance between the two corner portions 26a and 26b is equal to or greater than a predetermined value, and thereby it is determined whether or not the two corner portions 26a and 26b can be gripped substantially at the same time. This criterion will be described below. One gripping hand 18a, 18b occupies a certain range. Therefore, when the distance between the two corner portions 26a and 26b is closer than the predetermined range, the two gripping hands 18a and 18b collide when gripping the respective corner portions 26a and 26b at the same time. Specifically, when the distance between the two corner portions 26a and 26b is shorter than the distance between the two gripping portions when the two gripping hands 18a and 18b are brought into contact with each other, the two gripping hands 18a and 18b It will collide. Further, for safety, a certain interference region is set around the gripping hands 18a and 18b, and the distance between the two corner portions 26a and 26b is larger than the distance between the two gripping portions when the interference regions are brought into contact with each other. If it is short, it may be determined that the two gripping hands 18a and 18b interfere with each other. As described above, when the distance between the two corner portions 26a and 26b is equal to or greater than a predetermined distance, the two gripping hands 18a and 18b do not collide and can be gripped at the same time. On the other hand, when the distance between the two corner portions 26a and 26b is less than a predetermined value, the two gripping hands 18a and 18b are predicted to collide and cannot be gripped at the same time. Therefore, it is determined whether or not the two corner portions 26a and 26b can be gripped substantially at the same time depending on whether or not the distance is equal to or greater than a predetermined distance.
Here, "substantially simultaneously gripping" is not limited to the case of completely simultaneously gripping, but the time interval between gripping the first corner and gripping the second corner is within a predetermined range. Including short cases. In addition, the condition of "grabbing substantially at the same time" is that the balance of the cloth piece 22 changes when there is a time between gripping the first corner and gripping the second corner. This is because the position of the second corner may change and the grip may not be possible.

<First gripping hand, second gripping hand>
The two corners 26a and 26b of the cloth piece 22 are gripped by the first and second gripping hands 18a and 18b, respectively. The first and second gripping hands 18a and 18b can move the two corner portions 26a and 26b recognized by the gripping determination unit 14 to positions where they can be gripped, respectively. The first and second gripping hands 18a and 18b may be connected to the first and second robot arms 27a and 27b, respectively, as shown in FIG. 2, for example. The first and second robot arms 27a, 27b may have three or more joints (three axes) rotatably connected. As a result, the movement when the two corners 26a and 26b of the cloth piece 22 are gripped by the first and second gripping hands 18a and 18b can be smoothly performed. Further, after gripping the corners 26a and 26b, the cloth piece 22 can be lifted by the first and second gripping hands 18a and 18b, and the side including the corners 26a and 26b can be smoothly developed into a straight line. More preferably, the first and second robot arms 27a and 27b are 7-axis robots. As a result, the degree of freedom in the posture that each robot arm can take is increased, and the gripping hand can be moved more smoothly.
The gripping hands 18a and 18b may be in a form capable of gripping the cloth piece 22.

<Sub camera>
The sub-camera 19 detects the suspended piece of cloth 22. When the sub-camera 19 detects that the cloth piece 22 is suspended from the cloth piece hanging portion (conveyor) 17, the operation of gripping the cloth piece 22 is started. The sub camera 19 may be a two-dimensional camera as long as it can detect the cloth piece 22 and can be used as long as it can be used normally.

<Control unit>
A control unit 10 that controls the entire cloth piece gripping device 20 may be provided. The control unit 10 may exist independently of the other members, or may be shared with a part of the other members. For example, it may be included in the three-dimensional measuring device 11, the gripping determination unit 14, or the sub camera 19. Further, the control unit 10 may include physical components of a normal personal computer, for example, a CPU, a memory, a storage unit, a display unit, an input unit, an interface, and the like.

Among the above-mentioned constituent members, the functional constituent members such as the three-dimensional shape calculation unit 13, the grip determination unit 14, the corner recognition unit 15, the gripability determination unit 16, and the control unit 10 are all mechanical. It is not limited to the case where it is realized by the configuration, and at least a part thereof may be realized by a computer program.

<How to hold a piece of cloth>
FIG. 4 is a flowchart of the cloth piece gripping method according to the first embodiment. This method of gripping the cloth piece will be described below.
(1) The cloth piece 22 is suspended (S01). For example, as shown in FIG. 2, the cloth piece 22 may be conveyed by a conveyor 17 so that the side 23 of the cloth piece 22 is suspended vertically downward. The conveyor 17 is stopped when a part of the cloth piece 22 hangs down to a predetermined position. The confirmation of the cloth piece 22 can be performed by the sub camera 19. Not limited to the conveyor 17, a piece of cloth may be hung with a hook or the like.
(2) Acquire the three-dimensional shape of the cloth piece 22 (S02). Specifically, it is shown in the flowchart of FIG. FIG. 5 is a flowchart showing details of the acquisition step of the three-dimensional shape of the cloth piece 22 of FIG.
2-1) An image including the side 23 of the cloth piece 22 is obtained by taking a picture from vertically below the cloth piece 22 with the three-dimensional camera 12 (S11).
2-2) The three-dimensional shape of the cloth piece 22 is acquired based on the captured image (S12).
The method of acquiring the three-dimensional shape can be used as long as it is a normally used method. For example, a light cutting method that irradiates a line-shaped laser beam, a phase shift method that acquires a three-dimensional shape from multiple images projected with a lattice pattern that is slightly out of phase, and other laser displacement meters. A scanning method or the like may be used.

(3) Recognize the two corners 26a and 26b of the cloth piece 22 (S03). Specifically, it is shown in the flowchart of FIG. FIG. 6 is a flowchart showing details of the recognition step of the two corners of the cloth piece of FIG.
3-1) The lowest point 24 vertically below the three-dimensional shape of the cloth piece 22 is detected (S21).
3-2) Both ends of the line 23 extending in both directions from the lowest point 24 are recognized as corners 26a and 26b, respectively (S22).
The method of recognizing the two corners is not limited to the above method, and may be another method.
(4) It is determined whether the two corners can be recognized (S04). If the two corners can be recognized (YES), the process proceeds to the next step S05, and if the two corners cannot be recognized (NO), the cloth piece 22 is discharged (S09). After that, the process returns to step S01, and the next piece of cloth is suspended.

(5) It is determined whether the distance between the two corners 26a and 26b is equal to or greater than a predetermined value (S05). The distance between the two corners 26a and 26b can be calculated from the three-dimensional coordinates of the two corners 26a and 26b obtained in the corner recognition step S03. When the distance between the two corners 26a and 26b is equal to or greater than a predetermined distance (YES), the process proceeds to the next step S06. When the distance between the two corners 26a and 26b is less than a predetermined value (NO), it is predicted that the two gripping hands 18a and 18b will interfere with each other (S08), and the cloth piece 22 is discharged (S09). In this case, the discharged cloth piece 22 may be collected and retried as the next cloth piece. After that, the process returns to step S01, and the next piece of cloth is suspended.
(6) The two corners 26a and 26b of the cloth piece 22 are gripped by a pair of gripping hands 18a and 18b (S06).
(7) The gripping of the two corners 26a and 26b of the cloth piece 22 is completed (S07).
As described above, when gripping the two corners 26a and 26b of the cloth piece 22, it is possible to confirm whether they interfere with each other and grip the cloth piece 22.

The cloth piece gripping method may be at least partially realized by a computer program.

It should be noted that the present disclosure includes appropriately combining any of the various embodiments and / or examples described above, and the respective embodiments and / or embodiments. The effects of the examples can be achieved.

According to the cloth piece gripping device and the cloth piece gripping method according to the present invention, when gripping the two corners of the cloth piece, it is possible to check whether they interfere with each other and grip the cloth piece.

1 CPU
2 Memory 3 Storage unit 4 Display unit 5 Input unit 6 Interface 10 Control unit 11 Three-dimensional measuring device 12 Three-dimensional camera 13 Three-dimensional shape calculation unit 14 Gripping judgment unit 15 Corner recognition unit 16 Gripping possibility judgment unit 17 Cloth piece hanging Department (conveyor)
18a First gripping hand 18b Second gripping hand 19 Sub camera 20 Cloth piece gripping device 22 Towel (cloth piece)
23 Edge
24 Lowest points 26a, 26b Corners 27a First robot arm 27b Second robot arm

Claims (11)

A three-dimensional measuring device that measures the three-dimensional shape of a suspended piece of cloth,
Based on the measured three-dimensional shape of the cloth piece, the two adjacent corners of the cloth piece are recognized, and the two corners are gripped depending on whether the distance between the two corners is equal to or greater than a predetermined value. A gripping judgment unit that judges whether it can be done, and
A pair of gripping hands that grip the two corners of the cloth piece, respectively.
A cloth piece gripping device. The three-dimensional measuring device is
A three-dimensional camera that shoots from vertically below the piece of cloth,
A three-dimensional shape calculation unit that acquires the three-dimensional shape of the cloth piece based on the image taken by the three-dimensional camera, and
The cloth piece gripping device according to claim 1. The gripping determination unit
A corner recognition unit that recognizes two adjacent corners of the cloth piece based on the three-dimensional shape of the cloth piece, and a corner recognition unit.
A gripping possibility determination unit for determining whether the two corners can be gripped substantially at the same time,
The cloth piece gripping device according to claim 1 or 2. The corner recognition unit detects the lowest point vertically below the three-dimensional shape of the measured cloth piece, and recognizes both ends of the line extending in both directions from the lowest point as corners. , The cloth piece gripping device according to claim 3. The gripping possibility determination unit calculates whether or not the pair of gripping hands physically interfere with each other when the pair of gripping hands grip the two corners substantially at the same time. The cloth piece gripping device according to claim 3 or 4, wherein it is determined whether or not the two corners can be gripped substantially at the same time. The cloth piece gripping device according to any one of claims 1 to 5, wherein the pair of gripping hands can each move the two corners recognized by the gripping determination unit to a grippable position. The cloth piece gripping device according to any one of claims 1 to 6, further comprising a cloth piece hanging portion for suspending the cloth piece. The cloth piece gripping device according to any one of claims 1 to 7, further comprising a sub camera for detecting the suspended piece of cloth. Steps to get the three-dimensional shape of a piece of cloth,
The step of recognizing the two corners of the cloth piece,
A step of determining whether or not the two corners of the cloth piece can be gripped substantially at the same time depending on whether or not the distance between the two corners is equal to or greater than a predetermined value.
A step of grasping the two corners of the fabric piece by the pair of gripping hands,
A method for gripping a piece of cloth, including. The step of acquiring the three-dimensional shape of the cloth piece is
The step of obtaining an image by taking a picture with a camera from vertically below the piece of cloth,
A step of acquiring the three-dimensional shape of the cloth piece based on the captured image, and
9. The cloth piece gripping method according to claim 9. The step of recognizing the two corners of the piece of cloth is
A step of detecting the lowest point vertically below the three-dimensional shape of the cloth piece, and
A step of recognizing both ends of a line extending in both directions from the lowest point as corners,
The cloth piece gripping method according to claim 9 or 10.

Images