JP2022174410A - Carrier system - Google Patents

Abstract

To provide a carrier system capable of setting each stopping position installed in front of an intersection at an equal distance from the intersection in all guide lines.SOLUTION: A carrier system includes: a guide line 10 with an intersection 15; an unmanned carrier 20 that travels while being guided on the guide line 10; an RFID tag 30 as a signal transmitter arranged at the cross section 15; and a receiver 40 installed on the unmanned carrier 20 and serving as a signal receiver receiving a signal transmitted from the RFID tag. The signal transmitted from the RFID tag 30 has an equal transmission distance from the intersection 15 on all the guide lines 10 extending at least from the intersection 15.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a transport system for transporting articles by an automatic guided vehicle that travels on a guide line having intersections.

2. Description of the Related Art Conventionally, in a factory or the like that manufactures a large number of parts, there are cases where parts are transported by a plurality of unmanned guided vehicles that run on a guide line made of running magnetic tape or the like laid on the floor. For example, in Patent Document 1, when a plurality of automatic guided vehicles travel on a travel route laid so as to patrol a plurality of zones having an intersection, entry control of the automatic guided vehicle entering the intersection is performed. describes that control is performed to alleviate traffic congestion and avoid concentration of automated guided vehicles in a specific zone.

JP 2010-79407 A

In a guide line having an intersection, there is a case where a signal is transmitted by radio from a transmitter installed at the intersection, and the signal is received by an unmanned guided vehicle to temporarily stop before the intersection. In this case, there is a demand to set the stop position set before the intersection at an equal distance from the intersection on all the guidance lines extending from the intersection.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a transport system that can set stop positions before an intersection at equal distances from the intersection on all guidance lines.

A transport system according to the present invention includes a guide line having an intersection, an automatic guided vehicle that travels while being guided by the guide line, a signal transmission device that is arranged at the intersection, and a signal that is mounted on the automatic guided vehicle. and a signal receiving device that receives a signal transmitted from the transmitting device, wherein the signal transmitted from the signal transmitting device has a transmission distance from the intersection on at least all of the guide lines extending from the intersection. equidistant.

ADVANTAGE OF THE INVENTION According to this invention, the conveyance system which can set the stop position installed before an intersection in equal distance from an intersection in all the guidance lines can be provided.

1 is a schematic diagram of a transport system according to an embodiment; FIG. 4 is a plan view schematically showing the vicinity of an intersection of guide lines in the transport system according to the embodiment; FIG. 3 is a block diagram showing the configuration of an RFID tag included in the transport system according to the embodiment; FIG. FIG. 2 is a plan view schematically showing a state in which an automatic guided vehicle stops before an intersection in the transport system according to the embodiment; It is a top view showing other examples of the mounting position of the receiver to the automatic guided vehicle according to the embodiment. FIG. 10 is a plan view showing still another example of the mounting position of the receiver on the automatic guided vehicle according to the embodiment; FIG. 10 is a diagram showing a modified example of the shape of the RFID tag in the transport system according to the embodiment;

Embodiments of the present invention will be described below.
FIG. 1 is a plan view schematically showing a transport system 1 according to an embodiment. The transport system 1 includes a guide line 10, a plurality of automated guided vehicles 20, RFID tags 30 installed on the guided line 10, receivers 40 mounted on the automated guided vehicles 20, and a management unit 50. . The RFID tag 30 is an example of a signal transmitting device. Receiver 40 is an example of a signal receiving device.

The guide line 10 of the embodiment is laid on the floor of, for example, a factory that manufactures a large number of parts and assemblies. The guide line 10 is a travel route along which a plurality of automatic guided vehicles 20 travel. The guide line 10 is constructed, for example, by laying a running magnetic tape on the floor along a required running route. The guide line 10 of the embodiment is laid in a substantially figure 8 shape so as to circulate through a plurality of areas, that is, a first area 51, a second area 52, a third area 53 and a fourth area 54. It has an intersection 15 . In each of the first area 51, the second area 52, the third area 53, and the fourth area 54, work corresponding to the process, such as processing of parts, assembly, and packing, is performed. Note that the number of areas is set as required, and is not limited to four. Further, the shape of the guide line 10 in plan view is a shape according to need, and is not limited to the shape of the embodiment.

The guide line 10 has a linear first line portion 11 and a linear second line portion 12 that intersect each other. The first line portion 11 and the second line portion 12 are orthogonal to each other at the intersection 15 . As shown in FIG. 3, the first line portion 11 includes two straight portions 11A and 11B with the intersection 15 therebetween, and the second line portion 12 includes two straight lines with the intersection 15 therebetween. It includes a portion 12A and a straight portion 12B. That is, four straight portions 11A, 11B, 12A, and 12B extend from the intersection 15, respectively.

Each of the plurality of automatic guided vehicles 20 is self-propelled along the guide line 10 by being guided by the guide line 10 . In the embodiment, the automatic guided vehicle 20 travels along the guide line 10 in a one-way direction in the direction of the arrow in FIG. In addition, the traveling direction of the automatic guided vehicle 20 is not limited to the direction of the embodiment, and the direction opposite to the embodiment, or the traveling direction is not limited to one direction, and is controlled to travel in both directions as necessary. In some cases.

Although not specifically illustrated, the unmanned guided vehicle 20 includes, for example, a vehicle body having a loading platform on which a plurality of parts can be mounted, wheels attached to the vehicle body, a magnetic detection sensor for detecting a running magnetic tape of the guide line 10, a magnetic A travel control unit or the like is provided for performing travel control in response to a detection signal or the like from a detection sensor. Traveling of each automatic guided vehicle 20 is controlled based on a control signal wirelessly transmitted from the management unit 50 .

The RFID tag 30 is embedded in the center of the intersection 15 on the floor. For example, as shown in FIG. 3, the RFID tag 30 includes an RFID element 31 made of an IC chip and an antenna 32 for communication. Note that the configuration of the RFID tag 30 is not limited to this. The RFID tag element 31 stores identification information for specifying the intersection 15 , such as the position of the intersection 15 and the number of the intersection 15 . A signal indicating information stored in the RFID element 31 is transmitted from the antenna 32 as information of the RFID tag 30 . Antenna 32 of the embodiment is an omnidirectional antenna. As shown in FIG. 3, the RFID tag 30 of the embodiment is formed in a circular plate shape. The circular plate-shaped RFID tag 30 is arranged at the intersection 15 so that its surface direction is substantially parallel to the floor surface on which the guide line 10 extends and its center is aligned with the center of the intersection 15 . Note that the RFID tag does not have to be embedded in the floor surface, and may be attached to the floor surface within a range that does not interfere with the passage of the dustless transport vehicle 20 .

The RFID tag 30 may be of either a passive type driven by radio waves received from the outside or an active type driven by a built-in battery, but the passive type is preferable from the viewpoint of long-term operation. Incidentally, in the case of the passive type, the RFID element 31 is unnecessary.

A signal transmitted from the RFID tag 30 is isotropically transmitted from the intersection 15 in all directions on the floor surface. Since the antenna 32 of the embodiment is omnidirectional, the signal transmitted from the RFID tag 30 is isotropically transmitted in all directions. A circular dashed line indicated by reference numeral 33 in FIG. The outermost edge of this transmission range 33 exhibits a circular shape at least on the horizontal plane from the center of the intersection 15 . In other words, the signal transmitted from the RFID tag 30 has the same transmission distance from the intersection 15 at each of the four straight portions 11A, 11B, 12A, and 12B extending from the intersection 15 . The term equidistant used here includes a range within which a similar state can be expected without being bound by a strict value or meaning. For example, differences on the order of ±10 mm are included in the present invention. Note that the shape of the outermost edge of the transmission range 33 may be distorted such that the portion corresponding to the guide line 10 is recessed toward the center side due to the influence of the magnetism of the guide line 10 .

The transmission distance of the signal transmitted from the RFID tag 30 is set according to, for example, the size of the automatic guided vehicle 20, and is set to within 150 mm, for example, but is not limited to this.

The receiver 40 is mounted on the automatic guided vehicle 20 . The receiver 40 of the embodiment is arranged at the center of the front end of the automatic guided vehicle 20 in the traveling direction. The receiver 40 has an antenna for communicating with the management unit 50, although not specifically illustrated. A signal transmitted from the RFID tag 30 is received via the receiver 40 and transmitted to the management section 50 via another antenna. The receiver 40 is mounted on all the automatic guided vehicles 20, but the mounting position of the receiver 40 is set in front of the intersection 15 so that the stop position of the automatic guided vehicle 20 is equidistant from the intersection 15. It is mounted at a common position in all automatic guided vehicles 20 .

The receiver 40 may be mounted at the center of the automatic guided vehicle 20 as shown in FIG. 5A, or may be arranged at one end and the other end of the automatic guided vehicle 20 in the running direction as shown in FIG. 5B. may have been When two receivers 40 are provided as shown in FIG. 5B, for example, an operation method is adopted in which the receiver 40 on the front side in the direction of travel is put into an operating state.

The running states of all the automatic guided vehicles 20 are transmitted from the receivers 40 of the respective automatic guided vehicles 20 to the management unit 50 . A control signal is transmitted from the management unit 50 to the receiver 40 of each automatic guided vehicle 20 based on the signal transmitted from the receiver 40 . Based on the control signal received by the receiver 40, each automatic guided vehicle 20 is subjected to feedback control of its running state such as running, stopping, running speed, and the like.

According to the transport system 1 of the embodiment having the above configuration, based on the control signal transmitted from the management unit 50, the plurality of automatic guided vehicles 20 equipped with a plurality of parts and assemblies move along the guide line 10. run. The plurality of automatic guided vehicles 20 patrol the first area 51, the second area 52, the third area 53, and the fourth area 54, perform predetermined processes in these areas, and advance to the next process. Parts, assemblies, and the like are placed on the transport vehicle 20 .

As shown in FIG. 4, when the automatic guided vehicle 20 approaches the intersection 15, the receiver 40 of the automatic guided vehicle 20 enters the transmission range 33 of the RFID tag 30 placed at the intersection 15. 40 receives the signal emitted by RFID tag 30 . A signal indicating that the RFID tag 30 has entered the transmission range 33 is transmitted from the receiver 40 to the management unit 50. Upon receiving the signal, the management unit 50 transmits a stop signal to the receiver 40, and the automatic guided vehicle 20 reaches the intersection. 15 is temporarily stopped at a predetermined distance. Instead of the management unit 50, the traveling control unit provided in the automatic guided vehicle 20 may directly stop the vehicle. Based on the received information of the RFID tag 30, the management unit 50 grasps the traveling position of the automatic guided vehicle 20 on the guide line 10 as operation control information. The temporarily stopped unmanned guided vehicle 20 resumes traveling and passes through the intersection 15 after a required stop time.

FIG. 4 shows a case where two automatic guided vehicles 20 enter the intersection 15 from the first line portion 11 and the second line portion 12 respectively. At this time, after both of the two automatic guided vehicles 20 temporarily stop, one of the automatic guided vehicles 20 goes straight and enters the intersection 15 based on the instruction of the management unit 50, and the other automatic guided vehicle 20 stops. state may be maintained. Alternatively, the management unit 50 may control such that one of the two automatic guided vehicles 20 stops and the other does not stop and goes straight to enter the intersection 15 .

In the embodiment, when riding the guide line 10, passing through the intersection 15 from the straight portion 11A of the first line portion 11, and turning to the straight portion 12B of the second line portion, the automatic guided vehicle 20 starts from the straight portion 11A. After entering the intersection 15, the vehicle turns right above the intersection 15, turns to the straight section 12B, and goes straight. The automatic guided vehicle 20 grasps the position of the intersection 15 based on the signal of the RFID tag 30 installed at the intersection 15 . Here, since the signal transmitted from the RFID tag 30 installed at the intersection 15 is transmitted isotropically in all directions from the intersection 15, the unmanned guided vehicle 20 enters from the straight section 11A. In either case of entering from the straight portion 12A, the vehicle can move directly above the intersection 15 by moving an equal distance after sensing the signal. In other words, since the signal is transmitted isotropically in all directions from the intersection 15, if the unmanned guided vehicle 20 is set to move the same distance after detecting the signal, it can be sent from any route. can stop just above the intersection 15.

For example, if the RFID tag 30 placed at the intersection 15 has a shape such as a rectangular shape or a strip shape and has a longitudinal direction and a lateral direction, the signal reachable distance from the center of the RFID tag 30 is usually along the longitudinal direction. The reaching distance in the direction along the lateral direction is shorter than the reaching distance in the direction. Therefore, when the automatic guided vehicle 20 is set to move a predetermined distance after detecting a signal, the automatic guided vehicle 20 entering the intersection 15 from the longitudinal direction and the automatic guided vehicle 20 entering the intersection 15 from the lateral direction It becomes difficult for the car 20 to stop right above the intersection 15, and after turning, it may not be possible to smoothly go straight to the straight section 11A or the straight section 12B, and there is a possibility that the car 20 may deviate from the guide line 10. There is also In addition, one side and the other side of the intersecting guide line 10 have different stop positions because the reception positions from the intersection 15 are different. On the other hand, in the embodiment, the signal transmitted from the RFID tag 30 installed at the intersection 15 is isotropically transmitted in all directions from the intersection 15, and the automatic guided vehicle 20 turns just above the intersection 15. After turning, it can be smoothly guided to the guidance line. In particular, when the shape of the RFID tag 30 is circular as in the embodiment, and the configuration is such that radio waves are transmitted in all directions from the center, signals are easily transmitted isotropically in all directions, which is preferable.

Note that the shape of the RFID tag 30 may be a square RFID tag 30 as shown in FIG. 6 instead of a circular shape. If the RFID tag 30 has a square shape, even if the center of the RFID tag 30 is aligned with the center of the intersection 15, the distance from the intersection 15 to the stop position can be made equal as in the case of the circular shape.

As described above, in all of the straight line portions 11A and 12A of the first line portion 11 and the straight portion 11B and the straight portion 12B of the second line portion 12 extending from the intersection 15, the stop positions are set at the same distance from the intersection 15. is not transmitted isotropically in all directions from the intersection 15, but at least the transmission distances on the straight line portions 11A, 12A, 11B and 12B are equal. .

The transport system 1 according to the embodiment described above has the following effects.

(1) The transportation system 1 according to the embodiment includes a guide line 10 having an intersection 15, an unmanned guided vehicle 20 guided along the guide line 10, and an RFID tag 30 as a signal transmission device arranged at the intersection 15. and a receiver 40 as a signal receiving device that is mounted on the automatic guided vehicle 20 and receives a signal transmitted from the RFID tag 30, and the signal transmitted from the RFID tag 30 is transmitted from at least all of the intersections 15. The transmission distance from the intersection 15 on the guidance line 10 is equidistant.

As a result, the stop positions installed before the intersection 15 can be set at equal distances from the intersection 15 on all the guide lines 10 .

(2) In the transport system according to the embodiment, the RFID tag 30 isotropically transmits signals in all directions from the intersection 15 .

As a result, even if the installation direction of the RFID tag 30 centered on the intersection 15, that is, the angle is changed, the signal transmission distance on the guide line 10 does not change, so the RFID tag 30 can be installed regardless of the direction. can be done.

(3) In the transport system according to the embodiment, the transmission distance of the signal transmitted from the RFID tag 30 is within 150 mm.

As a result, it is possible to secure a sufficient distance from the intersection 15 to the stop position. For example, when the width dimension of the automatic guided vehicle 20 is about 300 mm or less, collision between the automatic guided vehicles 20 approaching the intersection 15 is avoided. can do.

(4) In the transport system according to the embodiment, the RFID tag 30 preferably has a circular shape at least in the plane in which the guide line 10 extends.

This makes it easy to isotropically transmit the signal transmitted from the RFID tag 30 in all directions.

Although the embodiments have been described above, the present invention is not limited to the embodiments, and includes modifications, improvements, etc. within the scope of achieving the object of the present invention.

For example, the guidance line 10 may have multiple intersections 15 and the RFID tags 30 may be installed at all of the multiple intersections 15 .
The signal transmission device to be installed at the intersection 15 is not limited to the RFID tag 30, but may be any device that transmits a signal that can detect the position of the intersection 15 in the direction of the guide line 10. FIG.

1 transport system 10 guidance line 15 intersection 20 unmanned guided vehicle 30 RFID tag (signal transmitting device)
40 receiver (signal receiving device)

Claims (4)

a guidance line having an intersection;
an unmanned guided vehicle that travels while being guided by the guide line;
a signal transmission device arranged at the intersection;
A transport system comprising a signal receiving device mounted on the automatic guided vehicle and receiving a signal transmitted from the signal transmitting device,
The transportation system according to claim 1, wherein the signal transmitted from the signal transmitting device is at least equal distances from the intersection on all of the guide lines extending from the intersection. 2. The transportation system according to claim 1, wherein said signal transmission device isotropically transmits signals in all directions from said intersection. 3. The transport system according to claim 1, wherein the transmission distance of the signal transmitted from said signal transmission device is within 150 mm. The transport system according to any one of claims 1 to 3, wherein the signal transmission device has a circular shape at least in a plane in which the guide line extends.

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