JP2011073100A - Picking method and hand device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely pick an object in a box body by a hand in any shape and in any attitude. <P>SOLUTION: This picking method is provided for picking the object T in the box body B having the four corners by the hand. The hand includes four gripping claws 12a-12d extending in the substantially same direction and relatively moving in the plane direction substantially orthogonal to the same direction. First of all, the gripping claws 12a-12d of the hand are respectively made to enter the box body B via an opening, and are respectively arranged in the corners C1-C4. Afterwards, the object T is gripped by the four gripping claws 12a-12d by contacting with the object T by relatively moving the respective gripping claws 12a-12d in the plane direction so as to mutually approach. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a picking method and a hand device for picking an object with a hand having a plurality of gripping claws.

  Conventionally, for example, at a manufacturing site, picking of an object (target, for example, a component) (hand holding and moving the object) by a hand having a plurality of gripping claws has been performed.

  As such a hand, there exists a hand described in patent document 1, for example. This hand is configured so that a plurality of connecting rods having the same shape having a through hole for supporting the crankshaft can be picked simultaneously. Specifically, the hand has a support bar that is inserted through the through holes of the plurality of connecting rods, and two gripping claws that hold the connecting rod that is positioned in the forefront (support bar tip side). Since the connecting rod located in the forefront is gripped by the gripping claws, the other connecting rods are prevented from falling off from the support bar.

Japanese Utility Model Publication No.2-2234

  By the way, in practice, the hand described in Patent Document 1 is not only a hand that picks only one type of object so that only the connecting rod is picked, but also a highly versatile hand that can grip a plurality of types of objects having different shapes. Is used. Such a highly versatile hand includes three gripping claws. The three gripping claws grip the target waiting in a preferable posture (posture that does not fall out between the three gripping claws after gripping), so that the target is reliably picked.

  However, even with a hand having three gripping claws, reliable picking of the target may be difficult.

  When the object is accommodated in the box for protection, even if the object is waiting in a preferred posture, depending on the shape of the object, the object may be too close to the inner surface of the box and the gripping claw of the hand May interfere with the box.

  As a countermeasure, it is conceivable to make the box sufficiently large. However, in this case, the object in the box becomes free, and the object cannot be sufficiently protected by the box. In addition, since the object is in a free state, the object is not always waiting in a preferable posture.

  Therefore, an object of the present invention is to reliably pick the target out of the box with a hand regardless of the shape or posture of the target accommodated in the box.

In order to solve the above-mentioned problem, the invention according to claim 1 of the present application is
A picking method for picking an object arranged in a box having four corners by a hand through an opening of the box,
A first step in which each of the four gripping claws extending in substantially the same direction provided in the hand is inserted into the box through the opening and arranged at each corner;
After the first step, each of the four gripping claws of the hand is moved relative to the plane direction substantially orthogonal to the same direction so as to approach each other, and is brought into contact with the object by the four gripping claws. And a second step of gripping the object.

The invention according to claim 2
The picking method according to claim 1,
The first step includes
A third step of allowing only the tips of the four gripping claws of the hand to enter the box;
After the third step, by continuously increasing the distances of the four gripping claws of the hand, the tips of the gripping claws are first brought into contact with the wall surfaces between the corners, and then the tips of the gripping claws are placed between the corners. A fourth step of moving along the wall surface and arranging at each corner;
After the fourth step, the method includes a fifth step of moving the entire hand toward the box.

Furthermore, the invention described in claim 3
The picking method according to claim 2,
The hand is configured to support the four gripping claws integrally so as to be freely movable in the plane direction and freely rotatable around a rotation center line extending in the same direction. Features.

In addition, the invention according to claim 4
The picking method according to any one of claims 1 to 3,
At least one gripping claw of the hand is provided with a protrusion.

In addition, the invention according to claim 5
The picking method according to any one of claims 1 to 4,
A plurality of objects are housed in the same direction and stacked in the same direction,
In the second step, the plurality of objects stacked in the same direction are simultaneously gripped by four gripping claws.

In addition, the invention according to claim 6
The picking method according to any one of claims 1 to 4,
A plurality of objects are housed side by side in the plane direction in the box,
In the second step, a plurality of objects arranged in the planar direction are simultaneously held by four holding claws.

In addition, the invention described in claim 7
The picking method according to any one of claims 1 to 4,
A sixth step of placing the object gripped in the second step on an object accommodated in another box;
After the sixth step, a seventh step of arranging each of the four gripping claws of the hand at each corner;
After the seventh step, each of the four gripping claws of the hand moves relative to each other in the plane direction so as to approach each other to come into contact with the plurality of objects, thereby making the plurality of objects by the four gripping nails. And an eighth step of simultaneously gripping.

In addition, the invention according to claim 8
The picking method according to any one of claims 1 to 4,
A ninth step of arranging the target gripped in the second step side by side in the plane direction on a target accommodated in another box;
After the ninth step, a tenth step of arranging each of the four gripping claws of the hand at each corner;
After the tenth step, each of the four gripping claws of the hand moves relative to each other in the plane direction so as to approach each other to come into contact with the plurality of objects, thereby making the plurality of objects by the four gripping nails. And an eleventh step of simultaneously gripping

In addition, the invention according to claim 9
A hand device for picking an object arranged in a box having four corners through an opening of the box,
Four grip claws extending in substantially the same direction;
Claw moving means for relatively moving each of the four gripping claws in the same direction and a plane direction substantially orthogonal to the same direction;
Control means for controlling the claw moving means,
The control means controls the claw moving means to cause each of the four gripping claws to enter the box through the opening and to be arranged at each corner; and
After the first operation, the four gripping claws of the hand are moved relative to each other in the plane direction so as to approach each other and are brought into contact with the target, thereby holding the target with the four gripping claws. The second operation is performed.

  According to the present invention, the four gripping claws that extend in substantially the same direction and move relatively in a plane direction substantially orthogonal to the same direction are arranged at each of the four corners of the box, and then Move closer to touch the object. Thereby, the four gripping claws of the hand can reliably grip the object without interfering with the box.

  In addition, the object in the box is gripped in the form of a foam closure by the four gripping claws regardless of the posture. That is, the object is gripped by the four gripping claws in a direction from the four corners of the box in the direction toward the object, making it impossible to move in the plane direction. As a result, the object is reliably grasped by the four grasping claws.

  As a result, the object is reliably picked out of the box by a hand having four gripping claws.

It is the figure which showed schematically the structure of the hand which concerns on one Embodiment of this invention. It is a figure which shows schematically the drive mechanism of the hand shown in FIG. It is a figure which shows the box which concerns on the picking method of this invention, and the object of picking. It is a figure for demonstrating the picking method which concerns on this invention. It is the figure which showed schematically the structure of the improved form of the hand shown in FIG. It is a figure for demonstrating the positioning method to four corners of four holding claws. It is a figure for demonstrating the positioning method to the four corners of another four holding claws. It is a figure for demonstrating the method of picking a several object simultaneously. It is a figure for demonstrating another method of picking a several object simultaneously. It is a figure which shows the holding nail of the hand of another embodiment.

  FIG. 1 schematically shows a hand according to an embodiment of the present invention. The hand indicated by reference numeral 10 in FIG. 1 is provided at the tip of a robot (not shown) that can move the hand to an arbitrary position and take an arbitrary posture (one of the components). As included in the robot).

  The hand 10 includes four gripping claws 12a to 12d that grip a target. The grip claws 12a to 12d are rod-shaped and extend in substantially the same direction (Z-axis direction in the drawing). Further, the outer circumferences of the gripping claws 12a to 12d are covered with, for example, a rubber material or knurled so as to prevent slipping (in order to generate a large frictional force with a picking target). Note that the gripping claws 12a to 12d may have any shape as long as they are rod-shaped. However, since the gripping claws 12a to 12d enter the gap between the box and the target as described later, it is preferable that the gripping claws 12a to 12d be thin and rigid.

  Further, the four grip claws 12a to 12d are configured to be relatively movable in a plane direction (X-axis direction and Y-axis direction) substantially orthogonal to the Z-axis direction.

  Specifically, each of the gripping claws 12a and 12b is supported by the movable support portion 14a so that one end thereof can move in the Y-axis direction. Further, the gripping claws 12c and 12d are supported by a movable support portion 14b so that one end of each of the gripping claws 12c and 12d can move in the Y-axis direction.

  One end of each of the two movable support portions 14a and 14b is supported by the base portion 16 so as to be movable in the X-axis direction.

  Since the gripping claws 12a to 12d can move in the Y-axis direction and the movable support portions 14a and 14b can move in the X-axis direction, the four gripping claws 12a to 12d can be moved between them. An existing object can be gripped in the XY plane direction.

  FIG. 2 schematically shows an example of a mechanism for driving the four gripping claws 12a to 12d and the two movable support portions 14a and 14b.

  One end of the gripping claws 12a, 12b is fixed to nuts 22a, 22b which are screwed with a ball screw 20a extending in the Y-axis direction in the movable support portion 14a. One end of the ball screw 20a is drivingly connected to the servo motor 24a. When the ball screw 20a is rotated by the servo motor 24a, the distance between the gripping claws 12a and 12b is changed.

  Similarly, the gripping claws 12c and 12d are fixed at one end to nuts 22c and 22d screwed with a ball screw 20b extending in the Y-axis direction in the movable support portion 14b. One end of the ball screw 20b is drivingly connected to the servo motor 24b. When the ball screw 20b is rotated by the servo motor 24b, the distance between the gripping claws 12c and 12d is changed.

  One end of each of the movable support portions 14 a and 14 b is fixed to nuts 22 e and 22 f that are screwed with a ball screw 20 c extending in the X-axis direction in the base portion 16. One end of the ball screw 20c is drivingly connected to the servo motor 24c. When the ball screw 20c is rotated by the servo motor 24c, the distance between the movable support portions 14a and 14b is changed.

  By controlling the three servo motors 24a to 24c, the four grip claws 12a to 12d can be moved in the XY plane direction, and the grip force of the four grip claws 12a to 12d can be adjusted. Further, it is possible to detect the positional relationship between the four gripping claws 12a to 12d based on the rotation angles of the three servo motors 24a to 24c (that is, to control the positions of the four gripping claws 12a to 12d). be able to).

  The means for moving the four gripping claws 12a to 12d in the Y-axis direction and the means for moving the two movable support portions 14a and 14b in the X-axis direction are other than the ball screws 20a to 20c and the servo motors 24a to 24c. There may be. However, like the ball screws 20a to 20c and the servo motors 24a to 24c, it is possible to control the gripping force with respect to an object existing between the four gripping claws 12a to 12d, and to control the positions of the gripping claws 12a to 12d. Means are preferred.

  From here, the method of picking the object accommodated in the box using the above-described hand 10 will be described.

  FIG. 3 shows a target (target) T for picking in a state of being accommodated in the box B.

  In addition, the “box” referred to in this specification means a rectangular bottom wall BW on which the target T is placed, and surrounds the target T vertically from each side of the bottom wall BW. It consists of four side walls SW1 to SW4 that form corners (corners) C1 to C4, and includes openings through which the four gripping claws 12a to 12d of the hand 10 enter.

  In addition, the “target” in the present specification is a shape that can be accommodated in the box B and does not occupy the four corners C1 to C4 when accommodated. Therefore, an object having a shape that enters the box B without a gap does not correspond to the “target” in this specification.

  When the hand 10 shown in FIG. 1 picks the target T in the box B, first, the four gripping claws 12a to 12d are moved to the four corners C1 to C4 of the box B as shown in FIG. To position (align). At this time, the gripping claws 12a to 12d are substantially parallel to the side walls SW1 to SW4.

  The positioning of the four gripping claws 12a to 12d to the corners C1 to C4 is shown in FIG. 2, for example, with the robot to which the hand 10 is attached based on the position and posture of the box B detected by the camera. It is executed by controlling the three servo motors 24a to 24c (the robot and the servo motors 24a to 24c serve as the claw moving means of the four gripping claws 12a to 12d described in the claims. ing).

  Further, for example, if the shape, position, and orientation of the box B are always constant, that is, if the positions (coordinates) of the corners C1 to C4 are determined, the robot and the three servo motors 24a to 24c. And the four gripping claws 12a to 12d may be aligned with the four corners C1 to C4 of the box B.

  When the positioning of the four gripping claws 12a to 12d to the four corners C1 to C4 of the box B is completed, the servo motors 24a to 24c are controlled so that the gripping claws 12a to 12d approach each other. Move in the Y plane direction. Then, as shown in FIG. 4B, the four grip claws 12a to 12d are brought into contact with the target T. Thereby, the target T is gripped by the four gripping claws 12a to 12d.

  When the shape and material of the target T and the posture of the target T in the box B are known, that is, when the distance from each of the four corners C1 to C4 to the target T is known, the four gripping claws 12a ˜12d is moved to a position immediately before contacting the target T by controlling the servo motors 24a to 24c. Thereafter, the four gripping claws 12a to 12d are moved until they contact the target T while controlling the servo motors 24a to 24c to a constant torque. The contact of the four gripping claws 12a to 12d with the target T can be understood by changing the torque of the servo motors 24a to 24c.

  On the other hand, when the target T is unknown, that is, when the distance from each of the four corners C1 to C4 to the target T is unknown, the four gripping claws 12a to 12d are set to the servo motors 24a to 24c with a constant torque. It moves until it contacts the object T while controlling.

If the distance from each of the four corners C1 to C4 to the target T is known and there is no problem even if the four gripping claws 12a to 12d collide with the target T at high speed, the four gripping claws 12a to 12d may be moved to a position where they are surely in contact with the target T by controlling the servo motors 24a to 24c (based on a change in torque, the gripping claws 12a to 12d and the target T Do not perform verification).

  As shown in FIG. 4B, when all the four grip claws 12a to 12d come into contact with each other, the object T is brought into a form closure state.

  In this case, “form closure” means that an object placed on a plane is brought into contact with another object at four contact points except the point of contact with the plane, thereby restricting any movement and moving or posture. A state that cannot be changed at all.

  Specifically, the target T is gripped by the four gripping claws 12a to 12d in approximately directions from the four corners C1 to C4 of the box B toward the target T, so that FIG. The movement in the XY plane direction shown (moving direction of the four gripping claws) is made impossible. Thereby, the target T is reliably gripped by the four gripping claws 12a to 12d.

  When the gripping of the target T in the form closure state by the four gripping claws 12a to 12d is completed, the hand 10 is separated from the box B. As a result, the target T is picked out of the box B by the hand 10.

  According to the present embodiment, the four gripping claws 12a to 12d of the hand 10 move so as to approach each other after being arranged (aligned) at the four corners C1 to C4 of the box B, respectively. To contact the target T. Thereby, the four grip claws 12a to 12d of the hand 10 can reliably grip the target T without interfering with the box B.

  In addition, the target T in the box B is gripped in the form of a foam closure by the four gripping claws 12a to 12d regardless of the posture. That is, the object T is moved in the XY plane direction by being gripped by the four gripping claws 12a to 12d in the direction from the four corners C1 to C4 of the box B toward the target T. Is gripped while being disabled. Thereby, the target T is reliably gripped by the four gripping claws 12a to 12d.

  As a result, the target T is reliably picked out of the box B by the hand 10 including the four gripping claws 12a to 12d.

  Although the present invention has been described with reference to the above-described embodiment, the present invention is not limited to this.

  For example, the four gripping claws 12a to 12d of the hand 10 shown in FIG. 1 are integrated into a plane direction (X-axis direction and Y-axis) that is substantially orthogonal to the direction in which the gripping claws 12a to 12d extend (substantially Z-axis direction). The rotation center line CL may be freely rotatable about the rotation center line CL extending in the Z-axis direction.

  In this case, for example, as shown in FIG. 5, the hand 10 includes a rotation mechanism 50 that supports the base portion 16 so as to be freely rotatable around a rotation center line CL extending in the Z-axis direction, and the rotation mechanism 50 as a Y-axis. The linear guide 52 supports the linear guide 52 so as to freely reciprocate in the direction, and the linear guide 54 supports the linear guide 52 so as to freely reciprocate in the X-axis direction.

  The advantage by this is that it becomes easy to align the four holding claws 12a to 12d of the hand 10 with the four corners C1 to C4 of the box B.

  This will be specifically described with reference to FIG.

  First, as shown in FIG. 6A, the four gripping claws 12 a to 12 d of the hand 10 are aligned with the approximate center of the box B. At this time, the entire gripping claws 12a to 12d are not allowed to enter the box B, but only the tip is allowed to enter. That is, the tip is aligned above the object T accommodated in the box B. If there is no problem, the positioning of the tips of the gripping claws 12a to 12d may not be substantially in the center of the box B.

  When the alignment of the tips of the four gripping claws 12a to 12d of the hand 10 to the substantially central position of the box B is completed, each of the four gripping claws 12a to 12d is moved away from the other gripping claws ( For example, the three servo motors 24a to 24c shown in FIG. 2 are controlled so that the distance between the gripping claws is increased). Then, as shown in FIG. 6B, the tips of the four grip claws 12a to 12d are brought into contact with the four side walls SW1 to SW4 of the box B.

  Even after the tips of the four gripping claws 12a to 12d come into contact with the four side walls SW1 to SW4 of the box B, if the distance between the gripping claws is further increased, each of the four gripping claws 12a to 12d A front-end | tip moves toward corners C1-C4 along side wall SW1-SW4 which is contacting. For example, as shown in FIG. 6B, the tip of the gripping claw 12a moves toward the corner C1 along the side wall SW1. That is, the tips of the four gripping claws 12a to 12d are guided toward the corners C1 to C4 by the side walls SW1 to SW4. Finally, as shown in FIG. 6C, the tips of the four grip claws 12a to 12d are arranged at the four corners C1 to C4 of the box B. When the arrangement is completed, the enlargement of the distance between the holding claws is finished and the alignment is completed.

  The completion of the arrangement (positioning) of the tips of the gripping claws 12a to 12d at the four corners C1 to C4 can be understood from, for example, the change in torque of the servo motors 24a to 24c shown in FIG. When entering the corner, the tip cannot move from the corner, and the torque of the servo motors 24a to 24c increases).

  As shown in FIG. 5, this is possible because the hand 10 can freely move the four gripping claws 12a to 12d integrally in the X-axis direction and the Y-axis direction, and Z This is because the rotation center line CL extending in the axial direction is supported so as to be freely rotatable. That is, as shown in FIGS. 6A, 6B, and 6C in order, the four gripping claws 12a to 12d move so that the distance between the gripping claws increases, This is because the posture of the entire 10 can be changed.

  Thereby, for example, it is not necessary to check the posture of the box B with a camera and then control the distance between the four gripping claws 12a to 12d in accordance with the four corners C1 to C4 of the box B. That is, the positioning of the four gripping claws 12a to 12d to the four corners C1 to C4 of the box B can be easily performed.

  Note that the rotation mechanism 50, the linear guide 52, and the linear guide 54 shown in FIG. 5 have four corners C1 to C4 of the four gripping claws 12a to 12d as shown in FIGS. 6 (A) to 6 (C). It is assumed that the box B does not move or must not move during the alignment. As shown in FIGS. 7A to 7C, if the box B may move during alignment without changing the posture of the hand 10, the rotating mechanism 50 and the linear guide shown in FIG. 52 and the linear guide 54 are not necessary.

  In addition, in order to make the tips of the four gripping claws 12a to 12d easily move toward the corners C1 to C4 along the side walls SW1 to SW4 of the box B, the tips of the four gripping claws 12a to 12d are You may comprise the roller rotated centering | focusing on the rotation center line extended in a Z-axis direction.

  In addition, as shown in FIG. 2, in the case of the above-described embodiment, the four grip claws 12a to 12d are driven by the three drive sources (servo motors 24a to 24c), but the present invention is not limited to this. Absent.

  For example, each gripping claw may be driven by one drive source. In this case, each of the four gripping claws can be driven independently. For example, when the rigidity of the target is partially different, each gripping claw is moved at a different speed corresponding to the rigidity of the contacting part. Can be contacted. Further, for example, four grip claws may be driven by one drive source. In this case, the four grip claws need only be controlled by one drive source.

  In addition, as shown in FIGS. 3 and 4, in the case of the above-described embodiment, the hand 10 including the four gripping claws 12a to 12d picks up one target T, but the present invention is not limited to this. More than one is possible.

  For example, as shown in FIG. 8, even when two objects T1 and T2 are arranged side by side on the bottom wall BW of the box B, the two objects T1 and T2 are separated by the four gripping claws 12a to 12d. Can be picked at the same time.

  Specifically, it is a premise that the objects T1 and T2 are accommodated in the box B so as to be able to contact at least two points P1 and P2. Thereby, the target T1 can be brought into a form closure state by the contact points P1, P2 between the two gripping claws 12a, 12c and the target T2. On the other hand, similarly, the target T2 can be brought into a form closure state by the contact points P1 and P2 between the two gripping claws 12b and 12d and the target T1. As a result, the two objects T1 and T2 can be picked simultaneously by the four gripping claws 12a to 12d.

  Also, for example, as shown in FIG. 9, even when two objects T3 and T4 are stacked and accommodated in the box B, the two objects T3 and T4 are picked simultaneously by the four gripping claws 12a to 12d. can do.

  Specifically, it is a premise that the target T4 positioned on the bottom wall BW side can be gripped in a foam closure state by the four gripping claws 12a to 12d. That is, it is assumed that the target T3 on the target T4 does not interfere with the gripping of the target T4 in the form closure state.

  As shown in FIGS. 8 and 9, since a plurality of objects can be picked simultaneously, the plurality of objects can be moved to one target location in a short time.

  For example, it is assumed that the first object is accommodated in the first box and the second object is accommodated in the second box. In this case, first, the first object is picked from the first box by the hand, and the picked first object is put into the second box in which the second object is accommodated. Thereby, as shown in FIGS. 8 and 9, two objects are accommodated in one box. And the 1st and 2nd object accommodated in the 2nd box with the hand is picked simultaneously.

  This is when the first object is moved from the first box to the target location by the hand, and then the second object is moved from the second box to the target location by the hand. Of course, the movement time of the hand is naturally shortened. Thereby, for example, it is possible to shorten an assembly time for assembling a product by collecting a plurality of parts from a plurality of places into one place.

  In addition, at least one of the gripping claws 12a to 12d of the hand 10 may be provided with a protrusion that can reliably prevent the target T from falling from between the four gripping claws 12a to 12d.

  For example, the gripping claw 100 illustrated in FIG. 10A includes a plurality of spherical protrusions 102. Since the protrusions 102 partially support the target T from below, it is possible to prevent the target T from falling between the four gripping claws 100 more reliably. However, if the protrusion 102 is too large, it may not be possible to enter the four corners C1 to C4 of the box B depending on the shape of the target T.

  As a countermeasure, the protruding portion may protrude toward the center of the box after the gripping claws enter the box. That is, you may comprise a protrusion part so that advancement / retraction is possible toward a box center from a holding nail | claw.

  For example, as a protrusion that can be advanced and retracted, a grasping claw 200 shown in FIG. The balloon 202 is configured to be inflated when the gripping claws 200 have entered the box.

  As another example, the gripping claw 300 shown in FIG. 10C is configured such that the tip 302 bends in one direction. The tip 302 is configured to bend toward the center of the box when the gripping claw 300 has entered the box.

  In addition to the shape shown in FIG. 10, a plurality of protrusions formed on the gripping claws can be considered, but when the gripping claws are arranged at the corners of the box, they are at least partially directed toward the center of the box. A shape that protrudes toward the target is preferable. When the protruding portion has a shape that protrudes toward the side wall of the box, the protruding portion may interfere with the box when the gripping claw enters the corner.

  Finally, when supplemented and confirmed, the present invention shows that the object picked up by a hand having a plurality of gripping claws is shaped so as not to occupy a plurality of corners of the box when housed. This is based on the fact that there are many cases (in the case of an object accommodated in the box with almost no gap, it is taken out of the box by a method other than gripping).

B Box C1 to C4 Corner T Target 12a to 12d Holding claw

Claims (9)

A picking method for picking an object arranged in a box having four corners by a hand through an opening of the box,
A first step in which each of the four gripping claws extending in substantially the same direction provided in the hand is inserted into the box through the opening and arranged at each corner;
After the first step, each of the four gripping claws of the hand is moved relative to the plane direction substantially orthogonal to the same direction so as to approach each other, and is brought into contact with the object by the four gripping claws. And a second step of gripping an object. The picking method according to claim 1,
The first step includes
A third step of allowing only the tips of the four gripping claws of the hand to enter the box;
After the third step, by continuously increasing the distances of the four gripping claws of the hand, the tips of the gripping claws are first brought into contact with the wall surfaces between the corners, and then the tips of the gripping claws are placed between the corners. A fourth step of moving along the wall surface and arranging at each corner;
A picking method comprising: a fifth step of moving the entire hand toward the box after the fourth step. The picking method according to claim 2,
The hand is configured to support the four gripping claws integrally so as to be freely movable in the plane direction and freely rotatable around a rotation center line extending in the same direction. Characteristic picking method. The picking method according to any one of claims 1 to 3,
The picking method, wherein at least one gripping claw of the hand includes a protrusion. The picking method according to any one of claims 1 to 4,
A plurality of objects are housed in the same direction and stacked in the same direction,
In the second step, the plurality of objects stacked in the same direction are simultaneously gripped by four gripping claws. The picking method according to any one of claims 1 to 4,
A plurality of objects are housed side by side in the plane direction in the box,
In the second step, a plurality of objects arranged in the plane direction are simultaneously gripped by four gripping claws. The picking method according to any one of claims 1 to 4,
A sixth step of placing the object gripped in the second step on an object accommodated in another box;
After the sixth step, a seventh step of arranging each of the four gripping claws of the hand at each corner;
After the seventh step, each of the four gripping claws of the hand moves relative to each other in the plane direction so as to approach each other to come into contact with the plurality of objects, thereby making the plurality of objects by the four gripping nails. A picking method comprising: an eighth step of simultaneously gripping The picking method according to any one of claims 1 to 4,
A ninth step of arranging the target gripped in the second step side by side in the plane direction on a target accommodated in another box;
After the ninth step, a tenth step of arranging each of the four gripping claws of the hand at each corner;
After the tenth step, each of the four gripping claws of the hand moves relative to each other in the plane direction so as to approach each other to come into contact with the plurality of objects, thereby making the plurality of objects by the four gripping nails. A picking method comprising: an eleventh step of simultaneously gripping A hand device for picking an object arranged in a box having four corners through an opening of the box,
Four grip claws extending in substantially the same direction;
Claw moving means for relatively moving each of the four gripping claws in the same direction and a plane direction substantially orthogonal to the same direction;
Control means for controlling the claw moving means,
The control means controls the claw moving means to cause each of the four gripping claws to enter the box through the opening and to be arranged at each corner; and
After the first operation, the four gripping claws of the hand are moved relative to each other in the plane direction so as to approach each other and are brought into contact with the target, thereby holding the target with the four gripping claws. 2. A hand device that performs the operation of 2.

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