JPH029594A - Method and device for gripping object - Google Patents

Abstract

PURPOSE:To accomplish sure grasp of an object by installing a grasping hand and an object sensing device at the wrist flange of a robot with a certain distance between each other, thereby using the joint of an arm effectively and sensing the position of the object accurately and quickly without allowing the grasping hand to block the view field. CONSTITUTION:A grasping hand 1 for object and a sensing device 2 for sensing this object are installed at the wrist flange 31 of a multi-joint type robot 3 with a certain distance kept between each other. This wrist flange 31 is moved to generate alignment of roll-shaped object 5 with the sensing device 2, and thereby the position of object 5 is detected. Then the wrist flange 31 is moved to move the grasping hand 1 to the position of the detected object 5, which is thus grasped by the hand 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an article gripping method and apparatus, and particularly to an article gripping method and an apparatus for holding articles, and in particular, for holding holes in a core of a rolled article placed on a pallet. It can be suitably used for.

(Prior Art) As a conventional technique related to a method of gripping an article and a device thereof, there is known a technique described in Japanese Patent Application Laid-Open No. 58-149192.

To explain the conventional technology described in the above-mentioned publication, Japanese Patent Application Laid-Open No. 149192/1983 discloses that a first target position is moved by moving an arm, and an imaging means installed on the arm is used to locate the first target position. Image near °4 (imported to LJl,
Detect the characteristic image indicating the second target position from the captured image, and calculate the deviation between the second number and the number of votes. A positioning method for a robot arm is described in which the arm is moved from a first target position to a second target position based on the calculated deviation.

(Problems to be Solved by the Invention) However, the above-mentioned conventional technology has the following problems.

That is, as described in Japanese Patent Application Laid-Open No. 58-1491925, h
The robot arm positioning method used in the present invention calculates the opening between the first and second target positions while rotating the grasping arm to the retracted position so that the field of view of the imaging means is not obstructed. The arm is moved from the first target position to the second target position based on the calculated deviation, and after positioning the arm, the gripper is rotated to the gripping position. The mounted imaging means can only perform one movement less than the gripping arm, and the gripping arm cannot effectively utilize the arm's one arm function.

The object of the present invention is to solve the above problems and make the joints of the arm effective? It is an object of the present invention to provide a method and a device that can be used to accurately and quickly detect the position of an article without obstructing the field of view during gripping, and can reliably grip the article.

(Means for solving departmental problems) In the present invention, a gripper for gripping an article and a detection device for detecting the article are separated by a certain alternating layer, and the f:
6 is fixedly installed on the flange portion, and after detecting the position of the article by moving the wrist flange portion and aligning the article and the detection device, moves and assists the wrist flange portion. moving the gripper to the detected position of the article;
A method for gripping an article, characterized in that the article is gripped by the gripper, and the gripper for gripping the article and the detection device for detecting the article are at a constant distance l! ll fixedly installed on the wrist flange of the robot at a distance from each other, and - the above detection devices are arranged on the same circumference at approximately constant intervals.
The above object has been achieved by providing an article gripping device characterized by comprising a @ detector.

Note that it is preferable that the article is a roll-shaped article having circular holes.

Also, a detection device! If any one detector of t is inside the hole
! The detection device is moved approximately spirally until the position II is detected, and any one of the detectors at l@ is inside the hole:!
! 'I ''' f After detecting the device, depending on the detector detecting the position inside the hole; until all the detectors detect the position of ! The detection device may be moved in two predetermined directions to align the hole and the detection device.

(Example) Hereinafter, embodiments will be described based on the drawings.

First f, the article gripping device of this embodiment will be explained.

FIG. 2 is a plan view showing the roll-shaped article gripping device of this embodiment, and FIG. 3 is a front view thereof (a part of the roll-shaped article? The illustration is omitted). In these drawings, ( l) is a gripping hand for gripping the roll-shaped article (5);
) is a detection device for detecting the center of the hole in the roll-shaped article (5), and (3) is an articulated robot, which has a gripping hand (1) and a detection device (2) on its f-neck flange portion +311.
and are fixedly installed with a certain alternating layer between them. Also, (4
) is a roll-shaped article (5)? This is a turntable for rotating the installed pallet (6).

To explain in detail each part of the water device, the gripping hand f1) holds a roll-shaped article (5) having a circular hole.
As shown in FIGS. 4 to 7, three claws (11) that open and close in parallel to each other in the radial direction
). When gripping the roll-shaped article (5), insert the claw (
After inserting the l) almost perpendicularly with the l) closed, the nail
1) This can be done by opening. In addition, hole part 1'511
The clearance between the inner diameter of the hole (511) and the outer diameter of the claw (11) of the gripping hand (1) is usually small.
If you do not align the center of the nail (11) with the hole
l) cannot be inserted.

Further, the detection device 1 F2) includes a hole portion (51) to be detected.
The detector is equipped with four detectors (21) arranged at substantially constant intervals around a circumference E having a diameter smaller than the inner diameter of the detector. That is, as shown in Figures 8 to 13, detectors (21
) is provided. Note that the diameter of the above circle is slightly smaller than the diameter of the hole (51) to be detected (for example, the diameter of the hole (51)
If the inner diameter of 1) is 48 to 51 mm, the diameter of the circle in which the detector (21) is placed is 45 mm, and the inner diameter of hole i5+1 is 7 mm.
Detected in case of 3 to 76 fl! The diameter of the circle in which IIJ C2++ is placed is preferably 70mm). Also, detection!
/! (As 211, a laser light reflection type photoswitch is suitable.

Also, as shown in Fig. 1, the articulated robot (3) has a bracket (,!) on its wrist flange (31).
) through gripping...nd (1) and detection device! +2) are fixedly installed at a certain distance. Note that since the eccentric direction of the gripping hand (1) and the detection device (2) is determined by the angle of the wrist flange (31), the detection device (2) detects the hole (51) of the roll-shaped article (5). By detecting this and moving the gripping hand (1) by the predetermined distance in the eccentric direction, the gripping hand (1) can be moved to the position of the hole 6 of the roll-shaped article (5). The gripping device for a roll-shaped article shown in FIG. 21a) ,...
It is equipped with two sets of detection devices (2) consisting of (21b)...

Further, the roll-shaped article (5) is a web of paper, nonwoven fabric, etc. wound around a core (paper tube).

Next, an embodiment of the article gripping method of this embodiment will be described based on an embodiment in which it is used in the above-mentioned roll-shaped article gripping device z.

In one embodiment of the article gripping method of the present invention, the above-mentioned 4 (any one detector hammer along the detector of il) is
The detection device (2) is moved in a substantially spiral shape by moving the handle flange (31) until it detects the position inside the hole C51) of the roll-shaped article (5). After detecting the position inside the detector (211 is the hole width), the position inside the hole 61) is detected until all the detectors (two plates) detect the position inside the hole width). According to the detection being detected: 5211, the detected value [(2) is moved by a predetermined amount in a predetermined direction, and the center of the detection device 2+21 and the center of the hole 61) are moved. By aligning the holes! 511, the angle of the wrist flange (31) and the eccentricity between the gripping hand i11 and the detector [(2+)
By moving the flange part (31), the gripping hand (1) is moved to the position of the hole part 61), and the gripping hand (1) is moved to the position of the hole part 61).
Gripping hand (1)? There is no way to hold it more than this.

As shown in FIGS. 2 and 3, roll-shaped articles (5) stacked in multiple stages at four locations on a pallet (6) are placed on a turntable (4), and a gripping command for the roll-shaped articles (5) is issued. If so, the search for holes <511 in the roll-shaped article (5) begins.

First, in order to confirm the presence or absence of the roll-shaped article (5), the standard placement position (
The detection device (2) is moved to a point that is more than the maximum placement error from point AO) (see Figure 15), and at that position V, 4I! Is the detection "rj of 9 (one or more detections 75 r21 out of 211) reflected light from the roll-shaped article (5)?"
It is checked whether it is detected (or not). If at least one detector (21) is turned on, the presence of the rolled article (5) is confirmed. Incidentally, if all the detections are "a" (211 does not detect reflected light and is off), the meridian of the roll-shaped article (5) is confirmed, so an abnormality command is issued and the system waits.

When the presence of the roll-shaped article (5) is confirmed, the detection device (
2) is moved to the floating placement position (+Fan AO) of the hole (51) of the roll-shaped article (5). At this time, if the roll-shaped article (5) is placed without error, all four detections 7m+21) are turned off, and the alignment is completed. If the roll-shaped article (5) is placed with an error, at least one of the four detections D (21) is turned on. Note that the roll-shaped article (5) is placed with a slight error, and at least one detected m
If +211 is in the OFF state, alignment will be performed as described later.

If all four detection Ws (211) are turned on, it means that the error in placing the p-ru-shaped article (5) is too large;
This is when all of the detectors (211) are not detecting the position inside the hole l51 of the roll-shaped article (5). In this case, as shown in the flowchart of FIG. 14, the center of the detection device (2) and the center of the hole (511) are aligned.

That is, when all four detectors ψl) are on, by moving the wrist flange (31), the points AO (XO, yo) and A11 (XO+
Detection device so that ΔX, YO) are connected with a straight line! ? (2) is moved, and if none of the four detection devices 5+21) turn off during the movement, the detection device (2) is further moved to point Al l, point A12 (XOYO+ΔY), point A12 (XOYO+ΔY), and point A13 (XO-ΔX, YO), point A14 (XO, Y
If the detection device (2) is moved to connect O-ΔY) with a circular arc, and none of the four detectors I21) turn off during the movement, A21 (XO+
2ΔX, YO), A22 (XO, YO+2'AY)
, A23 (XO-2ΔX, YO), A24 (XO
, YO-2ΔY)... and the arc expands in a substantially (concentric) spiral shape. If any one of the detectors (21) turns off during the movement of the detection device (2), the detection device (2)
stops the above-mentioned approximately spiral movement. That is, when the hole 60 of the roll-shaped article (5) is at the position 51α,
1 while the detection device (2) goes from point A31 to point A32.
The detection device i+211 is turned off, and the detection device I+211 is turned off.
(2+ stops the approximately spiral movement. Also, when the hole (51) of the roll-shaped article (5) is about 51β itt, the detection device 1 (2) moves from point A33 to point A34. One detector (21) is turned off at that time, and the detection device (2) stops moving in a substantially spiral shape.The above-mentioned substantially spiral movement path includes points A11, A12, and A12. A1
3, an arc connecting points A13, A14, and A21, an arc connecting points A21, A22, and A23, an arc connecting points A23, A24, and A31, a point A31,
Arc connecting point A32 and point A33, point A33, point A34,
It consists of a combination of arcs connecting point A41,... In addition, if the inner diameter of the hole button is 48 to 51 mm,
It is preferable that ΔX and ΔY be approximately +3Qm.

Detector size of any one of the four detectors (21) 1)
As illustrated in FIGS. 8 to 13, the detection device (
2) according to the table, move it by a small distance ΔX, Δy in either the X-axis direction or the Y-axis direction, or in both the X@force direction and the Y-axis direction (combined vector direction of the X-axis and Y-axis). (For example, in FIG. 8, the detection device (2) is
The detection device (2) is moved in the axial direction by 1 Δy), and depending on whether the four detector widths) are on or off after that movement, the detection device (2) is moved again according to the table, and thereafter the detection device (2) is moved in the same manner.・Repeat the detection, and as shown in Figure 13, 4
The process is repeated until all of the detectors Q1) are turned off, and the center of the detection device (2) and the center of the hole 61) are aligned. In addition, when the inner diameter of the hole T51) is 48 to 51 degrees, it is preferable that Δx1Δy- be 3-mn degrees, respectively.

Historically, the article gripping method of the present invention involves aligning the center of the detector rIl (21 and the center of the hole 61) as described above, thereby aligning the center of the hole (51) ( After detecting the position of the article, the flange part (31) is moved according to the angle of the wrist flange part 2 (31) and the eccentricity of the gripping/d (11) and the detection device (2). By doing this, you can grasp up to 1 loaf of the detected hole (5I).
Move the hand fl+ and grasp the hole (51).../do (
1) allows for gripping.

Grip (1) at the center position 1δ of the detected hole (51).
) will be described below.

The center position of the detected hole (51) is set as the robot center point (R
) is the orthogonal coordinate system on the earth (X, Y.

Z) is P, and the center position of the gripping hand 0) at that time is P2 in the same coordinate system, and the center point (F) of the wrist flange rule.
Let the position of P3 be in the same coordinate system.

The control point of the robot is the center point of the f-6 flange part 00 (F
), and at the time when the detection device (2) detects the center of the hole 60, the robot knows the position of that point (F) in the orthogonal coordinate system on the earth, and becomes P3. Also, at this time, the center position of the hole (51) is P, which coincides with the center position of the detection device (2).

Moreover, 167,972 copies (with point (F) or PJ as the origin)
The orthogonal coordinate system (FX, FY,
FZ), the center point (F) of the wrist flange part (31)
The relationship between the center position of the detection device (2) and the gripping hand (1) is FZ=A, FY=B, and is constant regardless of the position and orientation of the wrist flange (31). In order to move the gripping hand (1) to the center position of the hole detected by the robot, the center point (F) of the hand flange part (31) is moved to the wrist flange surface using the robot's control function 77. FY force direction FY = -B
If a command is given to move the gripping hand (1) by the center of the detected hole m (5!1?1 p1).

Although the embodiments of the article gripping method of the present invention have been described above, the present invention is not limited thereto.

In addition, although a laser light reflection type photoswitch was used as the detection D (211), the workpiece is metal and the detection device (
2) If the workpiece can be approached sufficiently, the detector (2I)
A proximity switch may also be used.

Also, instead of moving the detection device (2) approximately concentrically as shown in FIG. 15, as shown in FIG.
, YO) B12 (XO+Δx, yo+ΔY), B
13 (XOYO+ΔY), B14 (XO−ΔX,
YO+ΔY) B15(XO-ΔX, YO) B1
6 (XO-ΔX, YO-ΔY), B17 (XO, Y
O-ΔY), B18 (XO+2ΔX, Y-ΔY)...
The detector 1 (2) may be moved in a straight spiral shape, connecting the points .

In addition, when the inner diameter of the hole (51) is 48 to 51 mm, Δ
It is preferable to set X and ΔY to 30 m each (
ゝO It goes without saying that the article gripping method and device of this embodiment can also be applied to the case of gripping the outer circumference of a roll-shaped article by changing the shape of the gripping hand.

(Effects of the Invention) As described above, in the method of grasping an article according to the present invention, the grasping hand that grasps the article and the detection 1Lff that detects the article are placed at the flange portion of the hand G of the robot at a certain distance. Since it is fixedly installed, the joints of the articulated robot arm can be used effectively, and the gripping hand Z does not block the field of view of the detection device, so it is possible to accurately determine the location of the object. It can be detected quickly and gripped securely.

[Brief explanation of the drawing]

FIG. 1 is a bottom view showing the main parts of the article gripping device of this embodiment, FIG. 2 is a plan view showing the entire device, and FIG. 3 is a front view thereof (a part of the roll-shaped article is omitted). ), 4th
The figure is a partially cutaway front view showing the gripping throat 2, parts 5 to 7.
The figures are an S-8 view, a TT view, and a U-U view in FIG. , FIG. 14 is a flowchart thereof, FIG. 15 is an explanatory diagram showing the moving route of the detecting device, and FIG. 16 is an explanatory diagram showing another embodiment of the moving route of the detecting device. (1): Grip/end (2): Detector jd
(3): Articulated robot (-pot) (5) 2. Roll-shaped article (article) (211: Detector (311: Wrist flange portion 61) - Hole portion (hole) Patent Granted by Toujin Seibu'in Co., Ltd. Company (1 other person) Agent Ministry of Toshima Division 4 Figure 2 Figure 1 Figure 3 Figure 15 Y Vehicle weight SL: 4 Edo Hibiki (21) / j' All ON? S2:
jt-output device (2) k-mouth split curved width 1; strength ℃
S3: I @ I east or one unloading unit (21) or OFF? S4: Detection device (2) t3 output is generated at -Δ engineering direction in the tX-axis direction S5: f warehouse device (2) &X-axis or simply shield
Occurrence of Ogashiri υJ S7: Previous letter, 1 (2) iYTh
is the first time + Δψ frame tj Miho force generation S8 hardening device (
2) and the X-axis, Y-contention, and synthesis of the combination of the two;
F or diagram

Claims (1)

[Claims] 1) A gripping hand that grips an article and a detection device that detects the article are fixedly installed on the wrist flange of the robot at a certain distance apart, and move the wrist flange to detect the After detecting the position of the article by aligning the article with the detection device, the gripping hand is moved to the detected position of the article by moving the wrist flange portion, and the gripping hand is moved to the detected position of the article. A method of grasping an article, comprising grasping the article with the above-mentioned grasping hand. 2) A gripping hand that grips an article and a detection device that detects the article are fixedly installed on the wrist flange of the robot at a certain distance apart, and the detection devices are arranged on the same circumference at substantially constant intervals. An article gripping device comprising four detectors.