JP5229611B2 - Automatic traveling crane and its traveling position detection device - Google Patents

Description

  The present invention relates to a traveling position detection technique of an automatic traveling crane for accurately grasping a traveling position of a crane that automatically travels on a long distance traveling rail, and more particularly to an overhead traveling crane and a traveling position detection device thereof. It is.

  In the steel factory, a long intermediate yard with a total length exceeding 500 m is provided, and the coils from the pickling line and rolling line are temporarily stored in the yard and then sent to the next process. Although the coil is transported in such an intermediate yard by an overhead traveling crane, a single crane cannot cover such a wide range, so multiple cranes automatically travel simultaneously on the same traveling rail. I am letting. In order to automatically control these cranes so as not to collide with each other and to obtain the maximum working efficiency, it is necessary to always detect the traveling position of each crane with high accuracy.

  Conventionally, a laser rangefinder has been widely used to detect the traveling position of an automatic traveling crane, as disclosed in Patent Document 1. In Patent Document 1, a reflecting mirror is fixed to the wall surface of the end of the traveling rail, the laser beam emitted from the laser beam oscillator mounted on the crane is reflected, and the light is received and reflected by the laser receiver mounted on the crane. The position from the mirror can be accurately grasped.

  However, in the method of Patent Document 1, when three cranes are installed on a common traveling rail, the laser beam emitted from the central crane is blocked by other cranes. There is a drawback that the position of the central crane cannot be detected. Considering the formation of openings that allow laser beams to pass through the cranes on both sides, the light-transmitting area has traverse facilities, so it is difficult to move under the club, and the gap between the upper part of the crane and the ceiling is the first candidate. However, if the total length of the yard exceeds 500m, the size of the reflector will be as large as 2m x 2m considering the diffusion of the laser beam, so it will be difficult to secure a sufficient margin above the crane. It is not practical as equipment.

  The cranes on both sides detect the position by the method of Patent Document 1, while the laser beam emitted from the center crane is reflected by the reflectors provided on the side walls of the cranes on both sides, A method is also conceivable in which the relative position is detected and the position of the center crane is obtained by calculation. However, in this case, the positions of the cranes on both sides must be transmitted to the central crane, and there are cases where transmission and calculation require several tens of msec. There's a problem. Especially in crane automation when there are many obstacles in the yard, there is a safety problem, which is not practical.

  In addition, the inductive radio system and the IC tag system were also examined, but none of these could be used because the position resolution exceeded 10 mm and the responsiveness was poor.

Furthermore, in Patent Document 2, the coil position and the carriage position when the coil is automatically conveyed in the yard by the overhead crane are used in combination with optical means using a reflector and electromagnetic means using magnetism. A method of detecting is disclosed. However, this is not a method for detecting the traveling position of the overhead crane, but is not suitable for use in a method for accurately detecting the traveling position of an automatic traveling crane having a long traveling distance.
JP-A-11-344335 Japanese Patent Publication No. 61-31036

  In the case where the present invention solves the above-mentioned conventional problems and three or more cranes are arranged on a long running rail and there is not enough room to use a laser rangefinder above the crane. Another object of the present invention is to provide an automatic traveling crane capable of detecting the traveling position of each crane accurately and quickly, and a traveling position detecting device thereof.

  In a large yard with a total length of 500 m, the building itself where the traveling rail is installed expands or contracts due to a temperature difference between day and night or a temperature difference depending on the season. Accordingly, another object of the present invention is to provide an automatic traveling crane and a traveling position detection device thereof that do not cause a detection trouble due to expansion and contraction of the building.

The present invention made in order to solve the above problems is a traveling position detection device for an automatic traveling crane in which a plurality of cranes are arranged on the same traveling rail provided on a ceiling portion of a building to automatically travel each crane. , On the side of the transverse beam that supports the traveling rail of the crane, a large number of magnetic rods encoded magnetically are arranged in series over the entire length of the traveling section, and on the crane body that travels on the traveling rail, When one of the detection heads spans between the columns of the building, the other detection head does not span between the columns of the building. As described above, the vehicle is mounted with its position shifted in the traveling direction.

  As in claim 2, the magnetic rod is preferably one in which a plurality of magnets are embedded in a rod having a certain size, and as in claim 3, the detection heads are arranged at a predetermined pitch. It is preferable to have a large number of hall sensors.

  According to a fourth aspect of the present invention, the magnetic rod is preferably supported so as to be adjustable in height with respect to the cross beam. Furthermore, as described in claim 5, two or more detection heads are mounted with their positions shifted in the traveling direction so that one detection head can back up the other detection head when a detection abnormality occurs due to a gap between the magnetic rods. It is preferable that In the invention of claim 6, when it is determined that the data of one detection head is abnormal in detection, it is confirmed whether the data of the other detection head is normal, and the traveling direction between the two detection heads is It is preferable to correct the data by a distance corresponding to the directional position shift and switch the detection head data as the current position data.

  The automatic traveling crane of the present invention described in claim 7 is characterized in that the traveling position detection device for an automatic traveling crane according to any one of claims 1 to 6 is used as a traveling position detection device for each crane. To do.

  According to the first aspect of the present invention, the magnetic flux from a number of magnetic rods arranged in series over the entire length of the crane traveling section on the side of the transverse beam supporting the traveling rail is sensed by the detection head mounted on the crane body. To detect the absolute position. Since this position detection does not use a light beam, the traveling position of each crane can be detected without being affected by the adjacent crane as in the conventional case using a laser distance meter. In addition, according to the present invention, since a reflector as in the case of using a laser distance meter is not required, a sufficient margin around the crane is not required, and the traveling position of each crane can be detected with high accuracy.

  Moreover, since two or more detection heads are mounted with their positions shifted in the traveling direction, even if a detection trouble occurs in one of the detection heads due to the expansion and contraction of the building, the detection of the other detection head The head can be backed up immediately, and stable detection is always possible.

  If a magnetic rod in which a plurality of magnets are embedded in a rod of a certain size as in claim 2 and a detection head having a hall sensor as in claim 3 is used, The travel position can be detected with an accuracy of 0.1 mm by utilizing the fact that the voltage generated in the Hall sensor changes when the position relative to the magnet changes.

  The transverse beam supporting the magnetic rod and the traveling rail may cause a slight undulation deformation in the vertical direction over a long period of time, and the traveling rail itself may also be worn. If the height of the magnetic rod can be adjusted with respect to the transverse beam as in 4, the deviation in the height direction between the detection head and the magnetic rod can be easily corrected, and the detection accuracy is not lowered. Furthermore, as shown in claims 5 and 6, if one of the detection heads detects a detection abnormality due to a gap between the magnetic rods, the other detection head can be backed up, thereby avoiding a detection abnormality in a joint of the building. can do.

Preferred embodiments of the present invention are shown below.
FIG. 1 is a conceptual plan view of the entire yard 1 having a total length exceeding 500 m. Three cranes 3 are mounted on a pair of traveling rails 2 and 2 provided on the ceiling of the building. . These cranes 3 are automatic traveling overhead cranes. The yard 1 is connected to a plurality of lines from the coil loading line 4 from the previous process and the coil unloading line 5 to the next process, and the three cranes 3 are unloaded from the coil loading line 4, The temporary placement of the coil, the loading to the coil carry-out line 5 and the like are performed individually. The three cranes 3 are controlled by a control device (not shown) and perform these operations while automatically traveling. The traveling position detection device of the present invention described below is common to each crane 3.

  FIG. 2 is a front view of the crane 3, 10 is a crane girder that is a crane body, 11 is a club that can run on the crane girder 10, and 12 is a hoisting device provided in the club 11. Wheels 13 are provided at saddle portions at both ends of the crane girder 10, and traveling on the traveling rail 2 supported by the cross beam 14 of the building is the same as in a conventional overhead traveling crane.

  In the present invention, the magnetic rod 20 is arranged in series over the entire length of the traveling section on the side of the cross beam 14, and the detection head 30 mounted on the crane body detects the magnetic flux generated by the magnetic rod 20 to detect the position of the crane 3. The method to do is adopted.

  A magnetic rod 20 used in the present invention has a plurality of magnets embedded in a rod having the same length L. In this embodiment, as shown in FIG. The one in which the magnets 21, 22, 23 are embedded is used. FIG. 3 shows two magnetic rods 20. The distance between the magnet 21 and the magnet 22 is P1, the distance between the magnet 22 and the magnet 23 is P2, and the distance between the magnet 23 and the magnet 21 of the next magnetic rod 20 is P3. The same is true for the rod 20, and the distance of P2 + P3 is the same for any magnetic rod 20. However, the values of P2 and P3 themselves are slightly changed. For example, six types of magnetic rods 20 are manufactured as shown in Table 1 below. These six types of magnetic rods 20 are arranged in series in a specific order.

  Such a magnetic rod 20 is arrange | positioned at the side of the horizontal beam 14, as shown in FIG. As shown in an enlarged view in FIG. 4, it is preferable that the support 24 of the magnetic rod 20 can be adjusted in height with respect to the support base 25 provided on the side of the cross beam 14.

  On the other hand, the detection head 30 detects the position by sensing the magnetic flux generated by the magnet of the magnetic rod 20 with a Hall sensor. The Hall sensor uses the fact that when a perpendicular magnetic flux is applied to a semiconductor called a Hall element when a bias current is applied, an electromotive force proportional to the magnetic flux is generated between the output terminals by the Lorentz force. It is a sensor to detect. In the present invention, a detection head 30 in which such Hall sensors are arranged on a straight line at a constant pitch is used. In the example of Table 1, since the total length of the magnetic rod 20 is 1907 mm, the detection head 30 in which 192 Hall sensors are arranged at a pitch of 10 mm is used.

  As shown in FIG. 4, the detection head 30 has a side arm 31 protruding from the crane body and is attached to the upper surface thereof. In order to maintain the detection accuracy of the magnetic flux by the Hall sensor, the distance between the detection head 30 and the magnetic rod 20 needs to be within a certain range, and can be detected if the traveling rail 2 is worn or swelled. When it is out of the range, the height of the support 24 of the magnetic rod 20 is adjusted, and the distance between the detection head 30 and the magnetic rod 20 is adjusted within the detectable range. The interval guaranteed by the sensor manufacturer is 15 to 35 mm.

  FIG. 5 is a schematic diagram showing the output voltage of each Hall sensor of one detection head 30, and the output of the Hall sensor immediately before the magnets 21, 22, 23 of the magnetic rod 20 shows a peak value. As described above, since the values of P1 and P2 vary depending on the type (number) of the magnetic rod 20, it is possible to reliably detect which position of which magnetic rod 20 the detection head 30 is in. The detection accuracy in this method is 0.1 mm.

  However, in practice, it is difficult to accurately determine the distance between the end faces of the adjacent magnetic rods 20 and 20, and it is inevitable that the value of P3 in FIG. 3 varies. Sensor manufacturers have configured the detection circuit so that variations up to ± 2mm can be absorbed, but when applied to large buildings exceeding 500m, more variations will occur and detection anomalies may occur. It turns out that there is sex. That is, the cross beam 14 supporting the magnetic rod 20 is fixed to the upper part of the pillar of the building, but the building itself expands and contracts greatly due to a temperature difference between day and night and a temperature difference depending on the season. Due to the expansion and contraction of the building itself, the horizontal beam 14 also expands and contracts, so that the variation in the distance between the end surfaces of the magnetic rods 20 and 20 becomes 3 mm or more, and a detection abnormality may occur. If such a detection abnormality occurs, the control device cannot grasp the current position of the crane 3, and in the worst case, an accident such as a collision between the cranes 3 is caused. is there. If such a situation occurs frequently, the crane operation rate cannot be increased and it is not practical.

  Therefore, in the present invention, as shown in FIG. 6, when a plurality of detection heads 30, 30 are mounted with their positions shifted in the traveling direction of the crane and one of the detection heads 30 has a detection abnormality caused by the joint of the building, The other detection head 30 can be backed up. In this embodiment, the two detection heads 30 are installed in the crane body, and the controller that processes the output of the detection head 30 and sends it to the crane control device is also duplicated, so that position detection can be accurately performed even if a detection abnormality occurs. I did it.

  How much it is appropriate to shift the two detection heads 30 will be specifically described below. First, a range in which the detection abnormality NG may occur is shown in FIG. As shown in FIGS. 7C and 7D, not only the magnetic rod 20 installed between the building columns but also the case where the P3 side magnetic rod 20 shown in FIG. 3 extends between the building columns. , Detection abnormality may occur. For this reason, when one of the two detection heads 30 and 30 is in a position where the detection abnormality NG may occur, the other must be in the normal range.

  Even if the detection head 30 is out of the range where the detection abnormality NG may occur, it takes 200 to 300 ms to reset the communication line and return to normal, during which the distance traveled by the crane is several hundred mm. To reach. Therefore, the other detection head 30 must be in the normal range while the other detection head 30 travels several hundred mm after moving out of the range where the detection abnormality NG may occur. For this reason, the two detection heads 30 and 30 are separated from each other only (range in which detection abnormality NG may occur + distance traveled while resetting the communication line and returning to normal).

  In the example of FIG. 6, even if the detection head 30 on the left side becomes a detection abnormality due to an abnormal point between the magnetic rods 20, 20, the detection head 30 on the right side performs backup and continues position detection. For this purpose, each detection head 30 always performs position detection, and usually position control is performed based on the output of one of the detection heads 30, but at the same time as the detection abnormality occurs, the other detection head 30 is detected. Switching may be performed so as to perform position control based on the output.

This switching logic is based on the following steps, for example.
(1) It is determined whether the data of the detection head currently employed is normal. Judgment criteria include whether the data does not exceed the upper limit value, is not a negative value, or whether the difference from the previous value during one scan exceeds a predetermined value.
(2) If it is normal, it remains as it is, but when it is determined to be abnormal, it is switched after determining whether the data of the detection head on the opposite side is normal.
(3) At this time, the data is corrected by the distance corresponding to the positional deviation between the two detection heads described above to obtain the current position data.

  By using the above-described traveling position detection device for an automatic traveling crane according to the present invention, the traveling positions of a plurality of cranes that automatically travel on a traveling rail having a total length exceeding 500 m are always detected with an accuracy of 0.1 mm. It became possible to grasp accurately and quickly. Unlike the conventional laser rangefinder, the device of the present invention does not require a space for reflecting the laser beam around the crane, and can be applied to the expansion and contraction of the building and the wear of the running rail. It is an excellent device. The present invention makes it possible for the first time to automatically control a long-distance traveling crane exceeding 500 m, which has been impossible in the past. In the above embodiment, three cranes are shown, but it goes without saying that even if there are four or more cranes, they can be similarly controlled.

It is a conceptual top view of the whole yard where the crane was installed. It is a front view of a crane. It is explanatory drawing of a magnetic rod. It is explanatory drawing of the attachment state of a magnetic rod and a detection head. It is a schematic diagram which shows the output voltage of each Hall sensor of one detection head. It is explanatory drawing of the relationship between two detection heads and a magnetic rod. It is explanatory drawing which shows the relationship between a magnetic rod position and the range where detection abnormality NG may generate | occur | produce.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Yard 2 Traveling rail 3 Crane 4 Coil carrying-in line 5 Coil carrying-out line 10 Crane girder 11 Club 12 Hoisting device 13 Wheel 14 Cross beam 20 Magnetic rod 21 Magnet 22 Magnet 23 Magnet 24 Support tool 25 Support stand 30 Detection head 31 Horizontal arm

Claims (7)

In a traveling position detection device for an automatic traveling crane, in which a plurality of cranes are arranged on the same traveling rail provided on the ceiling portion of the building and each crane is automatically traveled, on the side of the lateral beam that supports the traveling rail of the crane. In addition, a number of magnetic rods whose positions are magnetically encoded are arranged in series over the entire length of the traveling section, and the absolute position is detected by sensing the magnetic flux generated by the magnetic rod on the crane body traveling on the traveling rail. Multiple detection heads to be detected are mounted so that when one detection head spans between the columns of the building, the other detection head is shifted in the running direction so as not to cross between the columns of the building A traveling position detection device for an automatic traveling crane.   2. The traveling position detecting device for an automatic traveling crane according to claim 1, wherein the magnetic rod has a plurality of magnets embedded in a rod having a certain size.   2. The traveling position detection device for an automatic traveling crane according to claim 1, wherein the detection head includes a plurality of hall sensors arranged at a predetermined pitch.   2. The traveling position detection device for an automatic traveling crane according to claim 1, wherein the magnetic rod is supported so as to be adjustable in height with respect to the transverse beam.   Two detection heads are mounted with their positions shifted in the traveling direction so that one detection head can back up the other detection head when a detection abnormality occurs due to a gap between the magnetic rods. The traveling position detection device for an automatic traveling crane according to claim 1.   If the data of one detection head is determined to be abnormal, check whether the data of the other detection head is normal and check that the distance between the two detection heads corresponds to the direction displacement in the traveling direction. The traveling position detection device for an automatic traveling crane according to claim 5, wherein the detected head data is switched as the current position data.   An automatic traveling crane using the traveling position detection device for an automatic traveling crane according to any one of claims 1 to 6 as a traveling position detection device for each crane.

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