JP2002003159A - Grasping and Positioning Method of Thin Coil in Automated Crane - Google Patents

Abstract

(57) [Problem] To easily perform not only the height direction of a coil but also the radial position correction in a short cycle time. SOLUTION: This is a method of positioning a gripping position when a cylindrical coil 4 is gripped and transported by an automated crane. Four sets of photoelectric switches 5 each consisting of four on each side of the arm claw 3 of the gripping device 1, four on each side
~ 8 are installed. Grasping device 1 during transfer of coil 4
The arm claw 3 and the hole 4 of the coil 4 are determined by the combination of the change of the light transmission and the light blocking state of the four sets of photoelectric switches 5 to 8 before, during, and after the lowering of the coil.
Then, the relative positional relationship with the position a is determined, and the arm claw 3 is corrected so as to be located at the center of the hole 4a of the coil 4. [Effect] Even if the arm claw and the coil hole are displaced not only in the height direction but also in the radial direction, it can be easily corrected with a short cycle time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of positioning a gripping position when a thin coil (hereinafter simply referred to as "coil") is conveyed, for example, when an overhead traveling crane is automated.

[0002]

2. Description of the Related Art In recent years, cranes have been automated for the purpose of labor saving. One of the challenges in automating cranes is always knowing how to accurately locate the coil. If there is an error in the coil position information (transmission information from the host computer or measured value, etc.), the error and the stop position error of the crane (the stop position error is usually at least ± 50 m for an automated crane)
m, and when it is large, it may occur about ± 100 mm. ) Is added, the center position of the coil is shifted from the center position of the coil and the center position of the coil is grasped, and when trying to grasp the coil, the claws of the grasping device do not enter the hole of the coil and normally touch the end face of the coil. If it cannot be grasped (gripping failure) occurs. Even if the crane stops accurately at the target stop position, if there is an error in the coil position information that is higher than the permissible accuracy, a gripping failure occurs as described above. Therefore, accurately knowing the position of the coil is very important in automating the crane.

[0003] As a means for accurately grasping the position of the coil, although it differs depending on the place where the coil is placed or in the state where the coil is placed, if it is placed on a fixed skid on the ground, for example, By measuring the absolute coordinates of the skid, the position of the coil can be ascertained.
Even if the coil storage space is a two-stage stack, the center position of the upper coil can be calculated from the outer diameter of the coil.

On the other hand, when the coil is not placed on the fixed skid as described above but on a moving truck such as a trailer or a truck, the stop reference position of the trailer or the truck and the above-mentioned position are set. Although the position of the coil can be known based on the absolute coordinates on the bogie, the stop position of the trailer or truck is not necessarily stopped at the stop reference position due to individual differences such as the driving skills of the driver. However, the position of the coil is not necessarily at the position according to the information, since it is stopped at a different position each time.

In order to solve such a problem, Japanese Patent Application Laid-Open No. 9-145315 discloses a method of measuring the outer diameter, width, and maximum height of a coil on a truck by image recognition by laser irradiation, and then measuring the center of the coil itself. A method is disclosed in which a position (X, Y, Z coordinates) is obtained by calculation to correct a stop error of a trailer or a truck, and this is used as a command value of a target stop position to control an automatic crane.

In Japanese Patent Application Laid-Open No. Hei 3-35816, two photoelectric switches are provided on the upper and lower portions of the claws of the arm of the gripper, and changes in the state of light shielding and light transmission of the photoelectric switch due to the coil end surface when the coil is lowered. A method of recognizing the position of the coil by measuring the outer diameter, the inner diameter, and the center position of the inner diameter of the coil is disclosed.

Further, in Japanese Patent Application Laid-Open No. 4-121391, even if there is an obstacle such as paper in the coil hole, the distance between the light emitter and the light receiver of the photoelectric switch provided above and below the claws of the arm of the gripper is set to 70 mm. A method has been disclosed which enables detection of a coil hole by allowing the coil hole to be extended to 100 m.

[0008]

SUMMARY OF THE INVENTION Incidentally, Japanese Patent Application Laid-Open No.
In the method disclosed in Japanese Patent No. 145315, the outer diameter, width, and maximum height of the coil are measured based on image recognition by laser irradiation. In addition, positioning in the traveling direction is performed, but about 30 seconds are required for the positioning, resulting in an increase in cycle time. When the number of coils to be transported is large, the efficiency is greatly reduced. Even if the position of the coil can be accurately determined, if a stop error in the coil radial direction that exceeds the allowable value that can be gripped at the time of positioning the coil of the automatic crane in the radial direction occurs, the claw portion of the gripping device is moved to the hole of the coil. , The gripping failure occurs by hitting the end face of the coil.

In the method disclosed in Japanese Patent Laid-Open No. 3-35816, the crane is positioned only in the vertical direction (height direction) of the coil. If the packing paper hangs on the hole of the coil being packed or if the packing paper closes the hole of the coil, a large error will occur in the calculation result. In addition, as a preliminary operation of the gripping device for calculation, it is necessary to lower the photoelectric switch for detecting the hole of the coil to the bottom of the coil, and then to position it at the center position of the coil obtained by calculation. Cycle time is increased due to increased useless movement, and a highly efficient automatic crane cannot be realized.

Further, the method disclosed in Japanese Patent Laid-Open No. 4-121391 does not have a function of correcting the position of the gripping device when the gripping device is displaced in the radial direction of the coil, similarly to Japanese Patent Application Laid-Open No. 3-35816. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems in the conventional method of gripping and positioning a coil in an automated crane, and has a short cycle not only in the height direction of the coil but also in the radial direction. It is an object of the present invention to provide a coil gripping and positioning method that can be easily performed in a short time.

[0012]

In order to achieve the above-mentioned object, a method for gripping and positioning a coil in an automated crane according to the present invention comprises a total of eight coils, four on each side, up and down and left and right of an arm claw portion of a gripper. Four sets of photoelectric switches are installed, and a set of light-transmitting and light-shielding states of the four sets of photoelectric switches in a stopped state before, during, or after the lowering of the gripping device during the transfer of the coil. The relative positional relationship between the arm claw and the coil hole is determined by matching, and the arm claw is corrected so as to be located at the center of the coil hole. By doing so, not only the height direction but also the radial position of the coil can be easily corrected with a short cycle time.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of gripping and positioning a coil in an automated crane according to the present invention is a method of positioning a gripping position when a coil wound in a cylindrical shape is gripped and transported by an automated crane. Four sets of photoelectric switches are installed on the upper and lower sides of the arm claw, four on each side, a total of eight, and before and after the lowering of the gripping device during the transfer of the coil, during the lowering, and in a stopped state after the lowering. The relative positional relationship between the arm claw and the hole of the coil is determined based on a combination of the light transmission and the change of the light blocking state of the set of photoelectric switches, and the arm claw is corrected so as to be located at the center of the hole of the coil. .

The method of gripping and positioning a coil in an automated crane according to the present invention is a method of gripping four sets of eight photoelectric switches, one on each side of the arm claw portion of the gripping device, four on each side, when transporting the coil. The relative positional relationship between the arm pawl and the coil hole is determined based on a combination of light transmission in the stopped state before, during, or after the lowering of the device, and the changing state of the light blocking state. The correction is made while observing the change of the light transmission and light blocking state of these eight sets of photoelectric switches so that they are located at the center of the hole, so that the arm claw and the hole of the coil are not only in the height direction but also in the radial direction Even if it is shifted, it can be easily corrected with a short cycle time.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for gripping and positioning a coil in an automated crane according to the present invention will be described below with reference to the embodiments shown in FIGS. FIG. 1 is a schematic view of a gripping device of an automated crane to which a method of gripping and positioning a coil in an automated crane according to the present invention is applied, (a) is a front view showing a corrected state of a gripping position, and (b) is a front view of (a). View AA,
FIGS. 2A to 2I are views showing the positional relationship between the coil end face and the grip position of the photoelectric switch before correction.

In FIG. 1, reference numeral 1 denotes a gripping device for an automated crane to which a method for gripping and positioning a coil in an automated crane according to the present invention is applied. It is inserted into the hole 4a of the coil 4, and the coil 4 is gripped and transported to a predetermined position.

Reference numerals 5a to 8a denote projectors, and reference numerals 5b to 8b denote light receivers which are paired with the aforementioned projectors 5a to 8a.
When the light emitted from a to 8a reaches the light receivers 5b to 8b, it is determined that there is no obstacle between them. In the automated crane gripping device to which the method for gripping and positioning the coil in the automated crane according to the present invention is applied, a total of eight photoelectric switches 5 to 8 including the light emitters 5a to 8a and the light receivers 5b to 8b are connected to an arm. It is set up, down, left and right of the nail 3 part. The upper, lower, left, and right installation positions of the photoelectric switches 5 to 8 are such that all the photoelectric switches 5 to 8 are located near the inner peripheral side of the hole 4 a of the coil 4 as shown in FIG. Position.

The method of gripping and positioning the coil in the automated crane according to the present invention is performed by the four sets of photoelectric switches 5 to 8 before, during and after the lowering of the gripping device 1 when the coil 4 is gripped. The relative positional relationship between the arm claw 3 and the hole 4a of the coil 4 is determined based on the combination of the change state of the light and the light blocking state.
The hole 4a is corrected so as to be located at the center of the hole 4a.

Hereinafter, various combinations of the light transmission of the four sets of photoelectric switches 5 to 8 and the change of the light blocking state before, during and after the lowering of the gripping device 1 when the coil 4 is gripped. And the respective correction methods will be described.

[FIGS. 1 (b) and 2 (a)] Grasping device 1
Before the winding down, all the photoelectric switches 5 to 8 are transmitting light, and during the lowering from this light transmitting state, after all the photoelectric switches 5 to 8 are in the light shielding state once and detect the end face of the coil 4 In the stopped state after the lowering, all the photoelectric switches 5 to 8 are again in the light-transmitting state and the coil 4
1B and FIG. 2A in which the hole 4a is detected, it is determined that the center of the gripping position of the gripper 1 is substantially at the center of the coil 4. Therefore, in such a case, it is unnecessary to correct the position of the gripping device 1 at the center of the coil 4.

[FIG. 2B] All photoelectric switches 5 to 8
Before the lowering of the gripping device 1 through which the light is passing, before the lowering, all the photoelectric switches 5 to 8 are temporarily in a light-shielding state to detect the end face of the coil 4, and in the stopped state after the lowering, FIG. 2 shows that only the photoelectric switches 6 and 8 on the right side of the drawing are in the light-transmitting state again while the photoelectric switches 5 and 7 on the left side remain in the light shielding state, and the hole 4 a of the coil 4 is detected.
In (b), the photoelectric switches 5 and 7 regard the state that the end face of the coil 4 is detected, and determine that the center of the gripping device 1 is shifted to the left side of the drawing with respect to the center of the coil 4. Therefore, in such a case, the grasping device 1 is moved to the right side of FIG. 2B until the photoelectric switches 5 and 7 together with the photoelectric switches 6 and 8 enter the light-transmitting state again and detect the hole 4 a of the coil 4. Move to

[FIG. 2 (c)] Up to the first half of the lowering, the state is the same as that of FIG. 2 (b). In the stopped state after the lowering, the photoelectric switches 5, 7, and 8 on the left side and the lower right side of the drawing remain in the light blocking state, and only the photoelectric switch 6 on the upper right side of the drawing enters the light transmitting state again, and the coil 4 is turned off. In FIG. 2C in which the hole 4a is detected, the photoelectric switches 5, 7, and 8 are deemed to have detected the end face of the coil 4, and the center of the gripping device 1 is shifted to the lower left side of the paper with respect to the center of the coil 4. Judge that Therefore, in such a case, the photoelectric switch 5 is used together with the photoelectric switch 6.
The gripping device 1 is moved to the upper right side in the drawing of FIG. 2B until the light transmission state of the coils 7 and 8 is detected again and the hole 4a of the coil 4 is detected.

[FIG. 2D] All photoelectric switches 5 to 8
Before the lowering of the gripping device 1 through which the light passes, the photoelectric switches 5 and 7 on the left side of the paper continue to maintain the light transmitting state through the middle of the lowering and continue until the stop state after the lowering. The photoelectric switches 6 and 8 of FIG. 1 are in a light-shielding state once during the lowering to detect the end face of the coil 4, and in a stopped state after the lowering, are in a light-transmitting state again and detect the hole 4 a of the coil 4. In (d), the photoelectric switches 5 and 7 have not detected the coil 4 itself. On the other hand, assuming that the photoelectric switches 6 and 8 have detected the hole 4a of the coil 4 as described above, the center of the gripping device 1 is further shifted to the left side of the drawing from the state of FIG. Judge that Therefore, in such a case, the grasping device 1 is moved until the photoelectric switches 5 and 7 together with the photoelectric switches 6 and 8 once enter a light-transmitting state through a light-shielding state and detect the hole 4a of the coil 4 in FIG.
(D) is moved to the right side of the drawing.

[FIG. 2 (e)] All photoelectric switches 5 to 8
Before the lowering of the gripping device 1 through which the light passes, the photoelectric switches 5 and 7 on the left side of the paper continue to maintain the light transmitting state through the middle of the lowering and continue until the stop state after the lowering. The photoelectric switches 6 and 8 of FIG. 2 are in a light-shielding state during the lowering, detect the end face of the coil 4, and then continue the light-shielding state until the stop state after the lowering.
In (e), the photoelectric switches 5 and 7 have never detected the coil 4 itself. On the other hand, photoelectric switch 6,
8 is regarded as a state in which the end face of the coil 4 is detected, and it is determined that the center of the gripping device 1 is further deviated from the state of FIG. Therefore,
In such a case, the photoelectric switches 5 and 7 go through the light-blocking state and then go into the light-passing state again, and the photoelectric switches 6 and 8 go into the light-passing state again and both the holes 4a of the coil 4
The gripping device 1 is moved to the right side of the paper of FIG.

[FIG. 2 (f)] All photoelectric switches 5 to 8
Before the lowering of the gripping device 1 through which the light is passing, before the lowering, all the photoelectric switches 5 to 8 are temporarily in a light-shielding state to detect the end face of the coil 4, and in the stopped state after the lowering, FIG. 2 shows that the photoelectric switches 6 and 8 on the right side remain in the light-shielded state, and only the photoelectric switches 5 and 7 on the left side of the drawing are in the light-transmitting state again to detect the hole 4 a of the coil 4.
In (f), the photoelectric switches 6 and 8 regard the state that the end face of the coil 4 has been detected, and determine that the center of the gripping device 1 is shifted to the right side of the paper with respect to the center of the coil 4. Therefore, in such a case, the grasping device 1 is moved to the left side of FIG. 2F until the photoelectric switches 6 and 8 together with the photoelectric switches 5 and 7 enter the light-transmitting state again and detect the hole 4 a of the coil 4. Move to

[FIG. 2 (g)] The state shown in FIG. 2 (f) is the same as that shown in FIG. 2 (f) up to the first half of the lowering. In the stop state after the lowering, the photoelectric switches 6, 7, and 8 on the right side and the lower left side of the drawing remain in the light shielding state, and only the photoelectric switch 5 on the upper left side of the drawing enters the light transmitting state again, and the hole 4a of the coil 4 becomes open. In FIG. 2 (g) in which is detected, the photoelectric switches 6, 7, 8 are regarded as detecting the end face of the coil 4, and the center of the gripping device 1 is positioned with respect to the center of the coil 4 in FIG. Judge that it is shifted to the lower right side. Therefore, in such a case, the grasping device 1 is moved to the upper left of FIG. 2 (g) until the photoelectric switches 6, 7, and 8 together with the photoelectric switch 5 enter the light-transmitting state again and detect the hole 4a of the coil 4. Move to the side.

[FIG. 2 (h)] All photoelectric switches 5 to 8
Before the lowering of the gripping device 1 through which the light passes, the photoelectric switches 6 and 8 on the right side of the paper continue to maintain the light transmitting state through the middle of the lowering and continue until the stop state after the lowering, and on the other hand, the left side of the paper The photoelectric switches 5 and 7 of FIG. 1 are in a light-shielding state during the lowering to detect the end face of the coil 4, and in a stopped state after the lowering, are in a light-transmitting state again to detect the hole 4 a of the coil 4. In 2 (h), the photoelectric switches 6 and 8 have never detected the coil 4 itself. On the other hand, assuming that the photoelectric switches 5 and 7 have detected the hole 4a of the coil 4 as described above, the center of the gripping device 1 is further shifted to the right side of the drawing from the state of FIG. Judge that Therefore, in such a case, the grasping device 1 is moved until the photoelectric switches 6 and 8 together with the photoelectric switches 5 and 7 are once again in the light-transmitting state through the light blocking state and the hole 4a of the coil 4 is detected.
(H) Move to the left side of the drawing.

[FIG. 2 (i)] All photoelectric switches 5 to 8
Before the lowering of the gripping device 1 through which the light passes, the photoelectric switches 6 and 8 on the right side of the paper continue to maintain the light transmitting state through the middle of the lowering and continue until the stop state after the lowering, and on the other hand, the left side of the paper FIG. 2 shows that the photoelectric switches 5 and 7 are in a light-shielding state during the lowering and detect the end surface of the coil 4, and then continue the light-shielding state until the stop state after the lowering.
In (i), the photoelectric switches 6 and 8 have never detected the coil 4 itself. On the other hand, photoelectric switch 5,
7 determines that the end face of the coil 4 has been detected, and determines that the center of the gripping device 1 is further deviated from the center of the coil 4 to the right side of the drawing from the state of FIG. Therefore,
In such a case, the photoelectric switches 6 and 8 are once again in the light-transmitting state after passing through the light-shielding state, and the photoelectric switches 5 and 7 are again in the light-transmitting state and are both in the hole 4a of the coil 4.
The gripping device 1 is moved to the left side in FIG.

The method of gripping and positioning the coil in the automated crane according to the present invention is not limited to the embodiment shown in FIG. The relative positional relationship between the arm claw 3 and the hole 4a of the coil 4 is determined by a combination of the light transmission of the four sets of photoelectric switches 5 to 8 and the change of the light-shielding state after the lowering. According to the relative positional relationship between the claw 3 and the hole 4a of the coil 4, the arm claw 3 may be appropriately corrected so as to be located at the center of the hole 4a of the coil 4.

[0030]

As described above, in the method for gripping and positioning a coil in an automated crane according to the present invention, four sets of photoelectric switches are provided, eight on each side, four on each side installed on the upper, lower, left and right sides of the arm claws of the gripper. The relative positional relationship between the arm claw and the hole of the coil is determined by the combination of the light transmission in the stopped state before, during, and after the lowering of the gripper during the transfer of the coil, and the changing state of the light blocking state. It is determined and corrected while observing the change of the light transmission and light blocking state of these eight sets of photoelectric switches so that the arm claw is positioned at the center of the hole of the coil. Even if it is shifted not only in the height direction but also in the radial direction,
It can be easily corrected with a short cycle time.

[Brief description of the drawings]

FIG. 1 is a schematic view of a gripping device of an automated crane to which a method for gripping and positioning a coil in an automated crane according to the present invention is applied, (a) is a front view showing a corrected state of a gripping position, and (b) is (a). FIG.

FIGS. 2A to 2I are views showing a positional relationship between a coil end face and a grip position of a photoelectric switch before correction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Grasp device 2 Arm 3 Arm claw 4 Coil 4a Hole 5-8 Photoelectric switch

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3F004 AE05 BA08 EA09 3F059 AA01 AA04 BA08 BC09 CA06 DA02 DA05 DA08 DC08 DD12 DE03 FA03 FB01 FB26 FC02 FC04 FC13 FC14 3F204 AA02 BA05 CA01 DA03 DB05 DC07

Claims (1)

[Claims] 1. A method of positioning a gripping position when a thin-plate coil wound in a cylindrical shape is gripped and transported by an automated crane. Four sets of photoelectric switches are installed, and before and after the lowering of the gripping device during the transfer of the thin-plate coil, the lowering of the gripping device is stopped.
The relative positional relationship between the arm pawl and the thin-plate coil hole is determined based on the combination of the light-transmitting and light-blocking state changes of the set of photoelectric switches, and correction is made so that the arm pawl is positioned at the center of the thin-plate coil hole. A method for gripping and positioning a thin plate coil in an automated crane, characterized by the following.