Unmanned carrier vehicle travelling system and unmanned carrier vehicle travelling method

Abstract

When an unmanned carrier vehicle (30) approaches any one of RFID tags (11) to (18), a control unit (65) of the unmanned carrier vehicle (30): determines an arrangement position, a normal-time operation command, and an abnormal-time operation command of the approached RFID tag read by an RFID reader (34); determines whether or not the arrangement position of said approached RFID tag is next to the arrangement position of another RFID tag that has been previously approached; and if the arrangement position of said approached RFID tag is next to the arrangement position of the other RFID tag, executes the normal-time operation command read from said approached RFID tag, and if the arrangement position is not next to the arrangement position of the other RFID tag, executes the abnormal-time operation command read from said approached RFID tag.

Description

Automatic guided vehicle driving system and automatic guided vehicle driving method

[0001] The present invention relates to an automated guided vehicle travel system and an automated guided vehicle travel method that allow an automated guided vehicle to travel along a travel line laid on a road surface, and in particular to a technology for controlling an automated guided vehicle when an abnormality occurs in the vehicle's travel along the travel line.

[0002] In an automated guided vehicle travel system, multiple RFID (Radio Frequency Identifier) ​​tags are sequentially placed along a travel line, and as an automated guided vehicle travels along the travel line and approaches each RFID tag in turn, the RFID reader of the automated guided vehicle reads an operation command from the RFID tag that it has approached, and the read operation command is executed by the automated guided vehicle. The operation command may be to travel, turn right or left, stop, perform a task, etc.

[0003] Furthermore, the automated guided vehicle described in Patent Document 1 is equipped with a marker detection sensor that detects magnetic markers and an RFID reader that reads information from RFID tags. The marker detection sensor detects and counts up magnetic markers attached to the floor surface, and the travel of the automated guided vehicle is controlled by commands corresponding to a predetermined count-up number. When the RFID reader reads information from the RFID tag, the travel of the automated guided vehicle is controlled by commands corresponding to the information, and the count-up number is reset. This resets the count-up number of the magnetic marker after reading the information from the RFID tag, making it easier to design a travel program.

[0004] Japanese Patent Application Laid-Open No. 2016-115207

[0005] As described above, as an automated guided vehicle travels along a travel line and approaches each RFID tag in turn, the RFID reader of the automated guided vehicle reads an operation command from the RFID tag it approaches, and the read operation command is executed by the automated guided vehicle. If the RFID reader skips reading an operation command from one RFID tag, the skipped operation command will not be executed by the automated guided vehicle, resulting in an operation error of the automated guided vehicle. Furthermore, when multiple automated guided vehicles are traveling along a travel line, an operation error in one automated guided vehicle will affect the operation of the other automated guided vehicles that follow.

[0006] Furthermore, in Patent Document 1, a magnetic marker is detected and counted up, and the travel of the automated guided vehicle is controlled by a command corresponding to a predetermined count-up number, and when an RFID reader reads the information from the RFID tag, not only is the travel of the automated guided vehicle controlled by a command corresponding to the information, but the count-up number is also reset, but there is no technical description of how to deal with operational errors in the automated guided vehicle such as those described above.

[0007] The present invention has been made in consideration of the above circumstances, and aims to make an automatic guided vehicle execute an operation command in the event of an abnormality when the RFID reader of the automatic guided vehicle misses reading an RFID tag.

[0008] An automated guided vehicle travel system according to one aspect of the present invention includes a travel line laid on a road surface, an automated guided vehicle that travels along the travel line, and a plurality of RFID tags that are sequentially arranged along the travel line and store an arrangement position along the travel line, an operation command for the automated guided vehicle in normal operation, and an operation command for the automated guided vehicle in abnormal operation, respectively. The automated guided vehicle is provided with an RFID reader that reads the RFID tag as the automated guided vehicle travels along the travel line and sequentially approaches each of the RFID tags, and the automated guided vehicle is provided with an RFID reader that reads the RFID tag as it approaches each of the RFID tags. and a control unit that, when approaching any of the RFID tags, determines the arrangement position of the approaching RFID tag read by the RFID reader, determines whether the arrangement position of the approaching RFID tag is the arrangement position next to the arrangement position of another RFID tag that was previously approached, and, if it is determined that it is the next arrangement position, executes the normal operation command read from the approaching RFID tag by the RFID reader, and, if it is determined that it is not the next arrangement position, executes the abnormal operation command read from the approaching RFID tag by the RFID reader.

[0009] An automated guided vehicle travel method according to one aspect of the present invention includes the steps of: each time an automated guided vehicle traveling along a travel line laid on a road surface approaches a plurality of RFID tags arranged in sequence along the travel line, reading from the approaching RFID tag by an RFID reader provided on the automated guided vehicle the arrangement position of the RFID tag along the travel line, a normal operation command, and an abnormal operation command for the automated guided vehicle; and when the automated guided vehicle approaches any of the RFID tags, determining the arrangement position of the approaching RFID tag read by the RFID reader, determining whether the arrangement position of the approaching RFID tag is the next arrangement position of another RFID tag that the automated guided vehicle approached previously, and if it is determined that the arrangement position is the next arrangement position, executing the normal operation command read from the approaching RFID tag by the RFID reader, and if it is determined that the arrangement position is not the next arrangement position, executing the abnormal operation command read from the approaching RFID tag by the RFID reader.

[0010] FIG. 1 is a schematic diagram showing an automated guided vehicle travel system according to one embodiment of the present invention. FIG. 2 is an enlarged plan view showing a travel line and an automated guided vehicle in the automated guided vehicle travel system of this embodiment. FIG. 3 is a perspective view showing an automated guided vehicle. (A) is a diagram showing the rotation of each drive wheel when the automated guided vehicle is moved forward, (B) is a diagram showing the rotation of each drive wheel when the automated guided vehicle is moved backward, (C) is a diagram showing the rotation of each drive wheel when the automated guided vehicle is turned right, and (D) is a diagram showing the rotation of each drive wheel when the automated guided vehicle is turned left. (A) and (B) are perspective views showing the operation when a storage case is sandwiched between the arms of the automated guided vehicle and received. (A) and (B) are perspective views showing the operation when a storage case is sandwiched between the arms of the automated guided vehicle and sent out. FIG. 1 is a block diagram showing the control system of the automated guided vehicle. FIG. 2 is a diagram showing the arrangement position, normal operation commands, and abnormal operation commands pre-stored in each RFID tag. 10 is a flowchart showing a control procedure for an automated guided vehicle based on the arrangement position stored in each RFID tag, an operation command in normal operation, and an operation command in abnormal operation.

[0011] An automated guided vehicle travel system and an automated guided vehicle travel method according to an embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a schematic diagram showing an automated guided vehicle travel system according to an embodiment of the present invention. The automated guided vehicle travel system Sy shown in Fig. 1 includes an oval travel line 10 laid on a road surface, a plurality of RFID tags 11-18 arranged along the travel line 10, and a plurality of automated guided vehicles 30 traveling along the travel line 10.

[0012] The unmanned transport vehicle 30 stops once at a standby position HP, travels from the standby position HP along the travel line 10 to a goods receiving position LP, stops and performs goods receiving work, travels from the goods receiving position LP along the travel line 10 to a goods sending position UP, stops and performs goods sending work, travels from the goods sending position UP along the travel line 10 to a charging position CP, stops and charges the power supply of the unmanned transport vehicle 30, and travels from the charging position CP along the travel line 10 to the standby position HP and returns.

[0013] 2 is an enlarged plan view showing the travel line 10, the RFID tags 11 to 18, the automated guided vehicle 30, etc. As shown in FIG. 2, the travel line 10 is a strip of uniform width and is, for example, black or gray. The color or density of the travel line 10 is darker than the color of the road surface.

[0014] The automated guided vehicle 30 is equipped with a line sensor 33 and an RFID reader 34. The line sensor 33 is provided at the center of the leading end of the automated guided vehicle 30, and detects the traveling line 10 over a range sufficiently wider than the width of the traveling line 10. Under the control of a control unit 65 (described later), the automated guided vehicle 30 steers in accordance with the position of the traveling line 10 detected by the line sensor 33, and travels along the traveling line 10. The control unit 65 controls the traveling of the automated guided vehicle 30 along the traveling line 10 using a known method, based on the contents of the traveling line 10 read by the line sensor 33.

[0015] The RFID reader 34 is provided near one end of the leading edge of the automated guided vehicle 30, and as the automated guided vehicle 30 travels along the travel line 10, it performs a reading operation on the RFID tag that it approaches and reads an operation command from the RFID tag that it approaches. Under the control of the control unit 65, the automated guided vehicle 30 travels, stops, and performs work in accordance with the read operation command.

[0016] Fig. 3 is an enlarged perspective view showing the automatic guided vehicle 30. As shown in Fig. 3, the automatic guided vehicle 30 is configured with a running section 36 provided on the lower side of the vehicle body and a working section 37 provided on the upper side of the vehicle body.

[0017] 2 and 3, casters 31 are provided at the four corners of the bottom of the running part 36, and four drive wheels 32 (corresponding to the steering running part in the claims) are provided on the inside of the bottom of the automatic guided vehicle 30, spaced apart from one another in a direction perpendicular to the running direction of the automatic guided vehicle 30, with the axes of the drive wheels 32 aligned in a straight line. Each drive wheel 32 is rotated by its own running drive motor, causing the automatic guided vehicle 30 to run, and each caster 31 to rotate in response.

[0018] When each drive wheel 32 is in contact with the floor surface, the travel drive motor of each drive wheel 32 is controlled to adjust the rotation speed of the drive wheel 32 and switch the rotation direction of the drive wheel 32, causing the unmanned guided vehicle 30 to travel, and the steering control of the unmanned guided vehicle 30 is performed to change the direction of travel of the unmanned guided vehicle 30, causing each caster 31 to rotate in response and change its direction.

[0019] As shown in FIG. 4A, when the automated guided vehicle 30 moves forward, the four drive wheels 32 are rotated at the same rotational speed in the direction in which the automated guided vehicle 30 moves forward (hereinafter referred to as the forward direction).

[0020] When the automated guided vehicle 30 is moved backward as shown in FIG. 4B, the four drive wheels 32 are rotated at the same rotational speed in the direction in which the automated guided vehicle 30 moves backward (hereinafter referred to as the reverse direction).

[0021] 4(C), when the direction of the automated guided vehicle 30 is changed to the right, the two left drive wheels 32 are rotated forward, and the two right drive wheels 32 are rotated forward at a slower rotational speed than the left drive wheels 32 or are stopped. In this case, the rotational speed of the left outer drive wheel 32 may be set to the fastest, the rotational speed of the left inner drive wheel 32 may be set to the second fastest, the rotational speed of the right inner drive wheel 32 may be set to the third fastest, and the rotational speed of the right outer drive wheel 32 may be set to the slowest or be stopped. By appropriately setting the rotational speeds of the four drive wheels 32, the turning radius of the automated guided vehicle 30 can be changed.

[0022] 4(D), when the direction of the automated guided vehicle 30 is changed to the left, the two right drive wheels 32 are rotated forward, and the two left drive wheels 32 are rotated forward at a slower rotational speed than the right drive wheels 32 or are stopped. In this case, the rotational speed of the right outer drive wheel 32 may be set to the fastest, the right inner drive wheel 32 to the second fastest, the left inner drive wheel 32 to the third fastest, and the left outer drive wheel 32 to the slowest or be stopped. By appropriately setting the rotational speeds of the four drive wheels 32, the turning radius of the automated guided vehicle 30 can be changed.

[0023] In this way, by controlling the rotation speed and rotation direction of each of the four drive wheels 32, the automated guided vehicle 30 can be made to move forward, backward, turn right, or turn left. The four casters 31 also change direction depending on the traveling direction of the automated guided vehicle 30, thereby stably supporting the automated guided vehicle 30 so that it can move freely. This makes it possible to stably change the direction of the automated guided vehicle 30 while it is traveling, despite the simple configuration.

[0024] Although four drive wheels 32 are provided here, a configuration with only two drive wheels 32 may also be provided. In a configuration with only two drive wheels 32, when the automated guided vehicle 30 is moved forward, the two drive wheels 32 are rotated at the same rotational speed in the direction in which the automated guided vehicle 30 moves forward (hereinafter referred to as the forward direction). When the automated guided vehicle 30 is moved backward, the two drive wheels 32 are rotated at the same rotational speed in the direction in which the automated guided vehicle 30 moves backward (hereinafter referred to as the reverse direction). When the direction of the automated guided vehicle 30 is changed to the right, one drive wheel 32 on the left side is rotated in the forward direction, and one drive wheel 32 on the right side is rotated in the forward direction at a rotational speed slower than that of the left drive wheel 32 or is stopped. When the direction of the unmanned transport vehicle 30 is changed to the left, one drive wheel 32 on the right side is rotated in the forward direction, and one drive wheel 32 on the left side is rotated in the forward direction at a rotation speed slower than that of each drive wheel 32 on the right side or is stopped.

[0025] As shown in FIG. 3 , the working unit 37 has a pair of support walls 41 that are opposed to each other and protrude from the work unit 37, and a respective arm 42 is provided on the outer side of each support wall 41. Each arm 42 is a hollow housing-like structure and is supported so as to be slidable along the respective support wall 41. The distance between the arms 42 is set to be slightly longer than the width of the case CS to be transported by the automatic guided vehicle 30, so that the case CS can be inserted and sandwiched between the arms 42. A respective rack gear (not shown) is provided on the lower end of each arm 42, and a respective pinion gear (not shown) is engaged with the respective rack gear. The pinion gears are rotated back and forth by the respective arm drive motors (shown in FIG. 7 ), causing each arm 42 to slide.

[0026] Each arm 42 has a slit 42A formed on the inside of its tip end, with a first claw 51 protruding through the slit 42A into the space between the arms 42, and a slit 42B formed on the inside of its rear end, with a second claw 52 protruding through the slit 42B into the space between the arms 42. The first claw 51 is connected to and supported by a shaft (not shown) parallel to the arm 42 on the inside of the arm 42, and this shaft is rotated back and forth by a claw drive motor 63 (shown in FIG. 7), causing the first claw 51 to protrude and retract through the slit 42A. Similarly, the second claw 52 is connected to and supported by a shaft parallel to the arm 42 on the inside of the arm 42, and this shaft is rotated back and forth by a claw drive motor 64 (shown in FIG. 7), causing the second claw 52 to protrude and retract through the slit 42B.

[0027] Here, the AGV 30 travels from the waiting position HP shown in FIG. 1 along the travel line 10 to the load receiving position LP and stops there. In this state, as shown in FIG. 5A, the arms 42 of the working unit 37 of the AGV 30 are extended, and a case CS placed on a loading platform (not shown) at the load receiving position LP is inserted and sandwiched between the arms 42, and the first claws 51 on the inside of the tip of each arm 42 are extended. Then, as shown in FIG. 5B, the arms 42 are retracted, and the first claws 51 hook onto the case CS, transferring the case CS from the loading platform to the working unit 37 of the AGV 30, and the first claws 51 are retracted. As a result, the working unit 37 of the AGV 30 receives the case CS from the loading platform at the load receiving position LP.

[0028] 1 along the travel line 10 and stops at the load-transfer position UP. In this state, the second claws 52 on the inside of the rear end of each arm 42 are extended as shown in FIG. 6A, and as shown in FIG. 6B, each arm 42 is extended toward the load platform (not shown) at the load-transfer position UP, each second claw 52 hooks onto the case CS, and the case CS is transferred from the working unit 37 of the automatic guided vehicle 30 to the load platform at the load-transfer position UP, and each second claw 52 is retracted. As a result, the working unit 37 of the automatic guided vehicle 30 sends the case CS onto the load platform at the load-transfer position UP.

[0029] Fig. 7 is a block diagram showing a control system of the automated guided vehicle 30. As shown in Fig. 7, the automated guided vehicle 30 includes travel drive motors 61 for rotationally driving the drive wheels 32 of the travel unit 36, arm drive motors 62 for horizontally moving the arms 42 of the working unit 37, claw drive motors 63 and 64 for projecting or retracting the first claws 51 and the second claws 52 from the slits 42A and 42B on the inside of both ends of each arm 42 into or from the spaces between the arms 42, the line sensor 33, the RFID reader 34, and a control unit 65.

[0030] The control unit 65 includes a processor, a RAM (Random Access Memory), a ROM (Read Only Memory), and a dedicated hardware circuit. The processor is, for example, a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), or an MPU (Micro Processing Unit). The control unit 65 executes a control program stored in the ROM to comprehensively control the automated guided vehicle 30.

[0031] For example, the control unit 65 detects the position of the traveling line 10 based on the detection output of the line sensor 33, and in accordance with the detected position of the traveling line 10, controls the driving of the traveling drive motor 61 of each driving wheel 32 separately, adjusts the rotation speed of the driving wheel 32, adjusts the direction of travel of the unmanned guided vehicle 30, and causes the unmanned guided vehicle 30 to travel along the traveling line 10.

[0032] Furthermore, each time the automated guided vehicle 30 approaches one of the RFID tags 11 to 18, the RFID reader 34 reads an operation command from the RFID tag that has approached it. The control unit 65 causes the automated guided vehicle 30 to travel or stop in accordance with the read operation command. As a result, the automated guided vehicle 30 travels or stops along the travel line 10 in the following order: standby position HP → load receiving position LP → load sending position UP → charging position CP → standby position HP, as shown in FIG.

[0033] Furthermore, the control unit 65 drives and controls each arm drive motor 62 in response to an operation command read by the RFID reader 34 from an approaching RFID tag to reciprocate each arm 42, and drives and controls each claw drive motor 63, 64 to protrude or retract each claw 51, 52 from the respective slits 42A, 42B formed on the inside of both ends of each arm 42. As a result, as shown in Figures 5(A) and (B), the working unit 37 of the automatic guided vehicle 30 receives the case CS from the loading platform at the load receiving position LP, and as shown in Figures 6(A) and (B), the working unit 37 of the automatic guided vehicle 30 sends out the case CS to the loading platform at the load sending position UP.

[0034] Here, as described above, each time the automated guided vehicle 30 travels along the travel line 10 and approaches each of the RFID tags 11 to 18 in sequence, the RFID reader 34 of the automated guided vehicle 30 reads an operation command from the approached RFID tag, and the read operation command is executed by the automated guided vehicle 30. In this case, if the RFID reader 34 skips reading an operation command from one or more RFID tags, the skipped operation command is not executed by the automated guided vehicle 30, resulting in an operation error of the automated guided vehicle 30. For example, if the automated guided vehicle 30 temporarily travels significantly deviated from the travel line 10, the RFID reader 34 may skip reading an operation command from one or more RFID tags.

[0035] Furthermore, when multiple unmanned guided vehicles 30 are traveling simultaneously along the travel line 10, an operational error in one unmanned guided vehicle 30 may affect the operation of another following unmanned guided vehicle 30, which may in turn affect the operation of still other following unmanned guided vehicles 30.

[0036] Therefore, in the automated guided vehicle travel system Sy of this embodiment, an arrangement position along the travel line 10, a normal operation command for the automated guided vehicle 30, and an abnormal operation command are stored for each RFID tag 11 to 18. In Fig. 1, the arrangement positions of the RFID tags 11 to 18 along the travel line 10 are indicated by P1 to P8, with arrangement position P1 indicating the first arrangement order, arrangement position P2 indicating the second arrangement order, and similarly, arrangement positions P3, P4, ..., P8 indicating the third, fourth, ..., eighth arrangement order.

[0037] FIG. 8 is a diagram ZH showing the array positions P1 to P8, normal operation commands, and abnormal operation commands pre-stored in each RFID tag 11 to 18. As shown in diagram ZH, normal operation commands and abnormal operation commands are set for each array position P1 to P8. For array position P1, the normal operation command is set to "start traveling from standby position HP," and the abnormal operation command is set to "turn right 90 degrees, travel straight for two seconds, stop." For array position P2, the normal operation command is set to "stop, work at loading position LP, resume traveling," and the abnormal operation command is set to "turn right 90 degrees, travel straight for two seconds, stop." For array position P3, the normal operation command is set to "turn right," and the abnormal operation command is set to "turn left 90 degrees, travel straight for two seconds, stop." At arrangement position P4, the normal operation command is set to "end turn," and the abnormal operation command is set to "turn left 90 degrees, drive straight for 2 seconds, stop." At arrangement position P5, the normal operation command is set to "stop, work at unloading position UP, resume driving," and the abnormal operation command is set to "turn right 90 degrees, drive straight for 2 seconds, stop." At arrangement position P6, the normal operation command is set to "stop, charge, resume driving," and the abnormal operation command is set to "turn right 90 degrees, drive straight for 2 seconds, stop." At arrangement position P7, the normal operation command is set to "turn right," and the abnormal operation command is set to "turn left 90 degrees, drive straight for 2 seconds, stop." At arrangement position P8, the normal operation command is set to "end turn," and the abnormal operation command is set to "turn left 90 degrees, drive straight for 2 seconds, stop."

[0038] When the unmanned guided vehicle 30 approaches any of the RFID tags 11 to 18, the control unit 65 of the unmanned guided vehicle 30 determines the arrangement position of the approaching RFID tag read by the RFID reader 34, determines whether the arrangement position of the approaching RFID tag is the arrangement position next to the arrangement position of another RFID tag that was previously approached, and if it determines that it is the next arrangement position, executes the normal operation command read by the RFID reader 34 from the approaching RFID tag, and if it determines that it is not the next arrangement position, executes the abnormal operation command read by the RFID reader 34 from the approaching RFID tag.

[0039] When the automated guided vehicle 30 is traveling along the travel line 10, the RFID reader 34 reads each RFID tag in the arrangement order of the RFID tags. Therefore, the control unit 65 of the automated guided vehicle 30 determines that the arrangement position read from an RFID tag that has approached by the RFID reader 34 is the arrangement position next to the arrangement position of another RFID tag that approached previously, and executes the normal operation command read from the approaching RFID tag.

[0040] Furthermore, if the AGV 30 temporarily deviates significantly from the travel line 10, the RFID reader 34 will skip over one or more RFID tags without reading them. Then, when the deviation of the AGV 30 from the travel line 10 is corrected and the AGV 30 approaches an RFID tag, the RFID reader 34 reads the alignment position, normal operation command, and abnormal operation command from the RFID tag. Therefore, the control unit 65 of the AGV 30 determines that the alignment position read from the RFID tag it approached is not the next alignment position of another RFID tag it approached previously, and executes the abnormal operation command read from the RFID tag it approached, causing the AGV 30 to make a 90-degree right or left turn, travel straight for two seconds, stop, and then remove the AGV 30 from the travel line 10. This allows the following AGV 30 to continue traveling and operating normally.

[0041] Next, the control procedure of the automatic guided vehicle 30 based on the arrangement positions P1 to P8 stored in each RFID tag 11 to 18 as described above, the operation commands in normal times, and the operation commands in abnormal times will be described with reference to the flowchart shown in FIG.

[0042] First, the automatic guided vehicle 30 is assumed to be located at the standby position HP. The control unit 65 of the automatic guided vehicle 30 sets the arrangement position of another RFID tag that the automatic guided vehicle 30 previously approached as the initial position P0 (S101), and then controls the driving of the driving motors 61 of the driving wheels 32 of the traveling unit 36 ​​individually according to the position of the traveling line 10 detected by the line sensor 33, thereby causing the automatic guided vehicle 30 to travel along the traveling line 10 (S102).

[0043] As the automated guided vehicle 30 travels along the travel line 10, it approaches one of the RFID tags 11 to 18. The control unit 65 of the automated guided vehicle 30 waits for the RFID reader 34 to read from the approached RFID tag ("No" in S103), and when the reading operation is performed ("Yes" in S103), it determines and acquires the arrangement position of the approached RFID tag read by the RFID reader 34, the normal operation command, and the abnormal operation command (S104).

[0044] As described above, the automated guided vehicle 30 is positioned at the standby position HP, so it travels along the travel line 10 and approaches the RFID tag 11 at the arrangement position P1. The control unit 65 of the automated guided vehicle 30 determines and acquires the arrangement position P1, the normal operation command, and the abnormal operation command read from the RFID tag 11 by the RFID reader 34 (S104). The arrangement position P1 is predetermined as the initial arrangement position from which the automated guided vehicle starts traveling.

[0045] When the control unit 65 of the unmanned guided vehicle 30 determines that the arrangement position of the RFID tag 11 determined in S104 is arrangement position P1 (S105 "Yes"), it determines whether the arrangement position of another RFID tag that approached last time is the initial position P0 (S106).

[0046] When the control unit 65 of the unmanned guided vehicle 30 determines that the arrangement position of another RFID tag that approached last time is the initial position P0 (S106 "Yes"), the normal operation command determined in S104, that is, the normal operation command read from the RFID tag 11 at arrangement position P1, is "start traveling from standby position HP", and therefore, according to the position of the traveling line 10 detected by the line sensor 33, the control unit 65 controls the driving of the traveling drive motor 61 of the driving wheel 32 for each driving wheel 32 of the traveling unit 36, to temporarily stop the unmanned guided vehicle 30 at the standby position HP, and causes the unmanned guided vehicle 30 to travel from the standby position HP (S107).

[0047] The control unit 65 of the automatic guided vehicle 30 sets the arrangement position P1 determined in S105 as the arrangement position previously approached (S108), and waits for the RFID reader 34 to read from the next approached RFID tag (S103 "No").

[0048] Here, it is assumed that the automated guided vehicle 30 approaches the RFID tag 12 at the next arrangement position P2 while traveling along the travel line 10. When the RFID reader 34 performs a reading operation from the next-approaching RFID tag 12 ("Yes" in S103), the control unit 65 of the automated guided vehicle 30 determines and acquires the arrangement position P2 of the RFID tag 12 read by the RFID reader 34, the normal operation command, and the abnormal operation command (S104).

[0049] At this time, the control unit 65 of the unmanned guided vehicle 30 determines that the arrangement position P2 of the next approaching RFID tag 12 is not arrangement position P1 (S105 "No"), and determines whether the arrangement position P2 of the next approaching RFID tag 12 is the arrangement position next to the arrangement position P1 of the previous approach that was set in S108 (S109).

[0050] In this case, the control unit 65 determines that the array position P2 of the next-approaching RFID tag 12 is the array position next to the array position P1 of the previous-approaching RFID tag 12 ("Yes" in S109). Since the normal operation command determined in S104, that is, the normal operation command read from the RFID tag 12 at array position P2, is "stop, work at load receiving position LP, resume traveling," the control unit 65 controls the driving of the driving motors 61 of the driving wheels 32 of the traveling unit 36 ​​to stop the automated guided vehicle 30, and controls the driving of the arm driving motors 62 and the claw driving motors 63, 64 of the working unit 37 to receive the case CS from the platform at the load receiving position LP onto the working unit 37, and resumes traveling of the automated guided vehicle 30 along the traveling line 10 (S110).

[0051] The control unit 65 of the automatic guided vehicle 30 sets the arrangement position P2 determined in S104 as the arrangement position previously approached (S111), and waits for the RFID reader 34 to read from the next approaching RFID tag (S103 "No").

[0052] Next, it is assumed that the automated guided vehicle 30 travels along the travel line 10 and approaches the RFID tag 13 at the next arrangement position P3. When the RFID reader 34 performs a reading operation from the next-approaching RFID tag 13 ("Yes" in S103), the control unit 65 of the automated guided vehicle 30 determines and acquires the arrangement position P3 of the RFID tag 13 read by the RFID reader 34, the normal operation command, and the abnormal operation command (S104).

[0053] The control unit 65 of the unmanned guided vehicle 30 determines that the arrangement position P3 of the next approaching RFID tag 13 is not arrangement position P1 (S105 "No"), and determines whether the arrangement position P3 of the next approaching RFID tag 13 is the arrangement position next to the arrangement position P2 of the previous approaching RFID tag 13 set in S111 (S109).

[0054] The control unit 65 of the unmanned guided vehicle 30 determines that the array position P3 of the next-approaching RFID tag 13 is the next array position after the array position P2 of the previous-approach set in S111 (S109 "Yes"), and since the normal operation command determined in S104, that is, the normal operation command read from the RFID tag 13 at array position P3, is "turn right," the control unit 65 controls the driving of the travel drive motors 61 of each drive wheel 32 of the running unit 36 ​​to turn right along the travel line 10 of the unmanned guided vehicle 30 (S110).

[0055] The control unit 65 of the automatic guided vehicle 30 sets the arrangement position P3 determined in S104 as the arrangement position previously approached (S111), and waits for the RFID reader 34 to perform a reading operation from the next approached RFID tag (S103 "No").

[0056] Furthermore, it is assumed that the automated guided vehicle 30 travels along the travel line 10 and approaches the RFID tag 14 at the next arrangement position P4. When the control unit 65 of the automated guided vehicle 30 performs a reading operation from the next approaching RFID tag 14 using the RFID reader 34 ("Yes" in S103), it determines and acquires the arrangement position P4 of the RFID tag 14 read by the RFID reader 34, the normal operation command, and the abnormal operation command (S104).

[0057] The control unit 65 of the unmanned guided vehicle 30 determines that the arrangement position P4 of the next approaching RFID tag 14 is not arrangement position P1 (S105 "No"), and determines whether the arrangement position P4 of the next approaching RFID tag 14 is the arrangement position next to the arrangement position P3 of the previous approach that was set in S111 (S109).

[0058] The control unit 65 of the unmanned guided vehicle 30 determines that the array position P4 of the next-approaching RFID tag 14 is the next array position after the array position P3 of the previous approach that was set in S111 (S109 "Yes"), and since the normal operation command determined in S104, that is, the normal operation command read from the RFID tag 14 at array position P4, is "end turning," the control unit 65 controls the driving of the travel drive motors 61 of each drive wheel 32 of the running unit 36 ​​to end the turning of the unmanned guided vehicle 30 and cause the unmanned guided vehicle 30 to travel along the travel line 10 (S110).

[0059] The control unit 65 of the automatic guided vehicle 30 sets the arrangement position P4 determined in S104 as the arrangement position previously approached (S111), and waits for the RFID reader 34 to read from the next approaching RFID tag (S103 "No").

[0060] Thereafter, as long as the automatic guided vehicle 30 travels along the travel line 10, it approaches the RFID tags 15 to 18 at the respective arrangement positions P5 to P8 in the same manner. In this case, when the RFID reader 34 performs a reading operation from the next approaching RFID tag (S103 "Yes"), the control unit 65 of the unmanned guided vehicle 30 determines and acquires the arrangement position of the RFID tag read by the RFID reader 34, the normal operation command, and the abnormal operation command (S104), determines that the arrangement position of the next approaching RFID tag is not arrangement position P1 (S105 "No"), determines that the arrangement position of the next approaching RFID tag is the arrangement position next to the arrangement position of the previous approach set in S111 (S109 "Yes"), executes the normal operation command determined in S104 (S110), sets the arrangement position determined in S104 as the arrangement position of the previous approach (S111), and waits for the RFID reader 34 to perform a reading operation from the next approaching RFID tag (S103 "No").

[0061] Therefore, since the normal operation command read from the RFID tag 15 at arrangement position P5 is "stop, work at cargo transfer position UP, resume driving," the control unit 65 of the unmanned guided vehicle 30 drives and controls the driving drive motors 61 of each drive wheel 32 of the running unit 36 ​​to stop the unmanned guided vehicle 30, and drives and controls the arm drive motors 62 and claw drive motors 63, 64 of the working unit 37 to send the case CS from the working unit 37 to the loading platform at the cargo transfer position UP, and resumes driving along the driving line 10 of the unmanned guided vehicle 30.

[0062] Furthermore, since the normal operation command read from the RFID tag 16 at arrangement position P6 is "stop, charge, resume running," the control unit 65 of the automatic guided vehicle 30 stops the automatic guided vehicle 30, charges the power supply (not shown) of the automatic guided vehicle 30, and resumes running of the automatic guided vehicle 30 along the travel line 10. The power supply of the automatic guided vehicle 30 is charged by, for example, wireless charging using a known electromagnetic induction method.

[0063] In addition, since the normal operation command read from the RFID tag 16 at arrangement position P7 is "turn right," the control unit 65 of the unmanned guided vehicle 30 turns right along the travel line 10 of the unmanned guided vehicle 30.

[0064] Furthermore, since the normal operation command read from the RFID tag 16 at arrangement position P8 is "end turning," the control unit 65 of the automatic guided vehicle 30 ends the turning of the automatic guided vehicle 30 and causes the automatic guided vehicle 30 to travel along the travel line 10. Incidentally, arrangement position P8 is predetermined as the final arrangement position.

[0065] Thereafter, the automated guided vehicle 30 travels along the travel line 10 and returns to the standby position HP. When the RFID reader 34 performs a reading operation from the RFID tag 11 ("Yes" in S103), the control unit 65 of the automated guided vehicle 30 determines and acquires the arrangement position P1 of the RFID tag 11 read by the RFID reader 34, the normal operation command, and the abnormal operation command (S104).

[0066] The control unit 65 of the unmanned guided vehicle 30 determines that the arrangement position P1 of the RFID tag 11 is arrangement position P1 (S105 "Yes"), and since the arrangement position P8 approached last time has been set in S111, determines that the arrangement position P8 approached last time is not the initial position P0 (S106 "No"), and when it determines that the arrangement position approached last time is the final arrangement position P8 (S112 "Yes"), it controls the driving of the travel drive motor 61 of the drive wheel 32 to stop the unmanned guided vehicle 30 at the standby position HP (S113), and ends the control procedure shown in Figure 9.

[0067] On the other hand, when the unmanned transport vehicle 30 is traveling at a large deviation from the travel line 10, the RFID reader 34 skips the reading operation for the RFID tags at one or more arrangement positions, and when the deviation of the unmanned transport vehicle 30 from the travel line 10 becomes small and the unmanned transport vehicle 30 returns to a state where it approaches other RFID tags, the RFID reader 34 performs the reading operation for the other RFID tags.

[0068] In this case, when the RFID reader 34 performs a reading operation from another RFID tag (S103 "Yes"), the control unit 65 of the unmanned guided vehicle 30 determines and obtains the arrangement position of the other RFID tag read by the RFID reader 34, the operation command under normal circumstances, and the operation command under abnormal circumstances (S104).

[0069] For example, if the other tag is one of the RFID tags 12 to 17, the control unit 65 of the unmanned guided vehicle 30 determines that the arrangement position of the other RFID tag is not arrangement position P1 (S105 "No"), and then determines whether the arrangement positions P2 to P7 of the other RFID tags 12 to 17 are the arrangement positions next to the arrangement position that was previously approached and set in S111 (S109).

[0070] As described above, if the RFID reader 34 skips the read operation for the RFID tag at one or more arrangement positions and performs a read operation for another RFID tag, the arrangement positions P2 to P8 of the other RFID tags 12 to 18 are different from the arrangement positions next to the arrangement positions previously approached, which were set in S111. Therefore, the control unit 65 of the automated guided vehicle 30 determines that the arrangement positions of the other RFID tags are not the arrangement positions next to the arrangement positions previously approached, which were set in S111 ("No" in S109), executes the operation command for the abnormality determined in S104 (S114), and causes the automated guided vehicle 30 to depart from the travel line 10 (S115). After this, the control procedure shown in FIG. 9 ends.

[0071] For example, if the control unit 65 of the automatic guided vehicle 30 determines that the array position P2 of another RFID tag 12 is not the next array position of the previously approached array position set in S111 ("No" in S109), the abnormality operation command read from the RFID tag 12 at array position P2 is "turn right 90 degrees, travel straight for two seconds, and stop," so the control unit 65 controls the driving of the travel drive motors 61 of the drive wheels 32 of the traveling unit 36 ​​to turn right, travel straight for two seconds, and then stop (S114), and causes the automatic guided vehicle 30 to leave the traveling line 10 to the inside (S115). After this, the control procedure shown in FIG. 9 ends.

[0072] Furthermore, if the control unit 65 of the automatic guided vehicle 30 determines that the arrangement positions P3, P4 of the other RFID tags 13, 14 are not the arrangement positions next to the arrangement position set in S111 to which the automatic guided vehicle 30 previously approached (S109 "No"), since the abnormality operation command read from the RFID tags 13, 14 at arrangement positions P3, P4 is "turn 90 degrees left, travel straight for two seconds, stop," the control unit 65 controls the driving of the travel drive motors 61 of the drive wheels 32 of the traveling unit 36 ​​to make the automatic guided vehicle 30 turn left, travel straight for two seconds, and then stop (S114), and move the automatic guided vehicle 30 away from the traveling line 10 (S115). After this, the control procedure shown in FIG. 9 ends.

[0073] Furthermore, if the control unit 65 of the automatic guided vehicle 30 determines that the arrangement positions P5, P6 of the other RFID tags 15, 16 are not the arrangement positions next to the arrangement position set in S111 to which the automatic guided vehicle 30 previously approached ("No" in S109), the abnormality operation command read from the RFID tags 15, 16 is "turn right 90 degrees, travel straight for two seconds, and stop," so the control unit 65 controls the driving of the travel drive motors 61 of the drive wheels 32 of the traveling unit 36 ​​to make the automatic guided vehicle 30 turn right, travel straight for two seconds, and then stop (S114), and then move the automatic guided vehicle 30 away from the inside of the traveling line 10 (S115). After this, the control procedure shown in FIG. 9 ends.

[0074] Furthermore, if the control unit 65 of the automated guided vehicle 30 determines that the arrangement positions P7, P8 of the next-approaching RFID tags 17, 18 are not the arrangement positions next to the arrangement positions of the previously-approached RFID tags set in S111 ("No" in S109), the abnormality operation command read from the RFID tags 18 at arrangement positions P7, P8 is "turn 90 degrees left, travel straight for two seconds, and stop," so the control unit 65 controls the driving of the travel drive motors 61 of the drive wheels 32 of the traveling unit 36 ​​to make the automated guided vehicle 30 turn left, travel straight for two seconds, and then stop (S114), and then move the automated guided vehicle 30 away from the traveling line 10 (S115). After this, the control procedure shown in FIG. 9 ends.

[0075] Furthermore, when the automatic guided vehicle 30 returns to the standby position HP as described above, the RFID reader 34 performs a reading operation on the first RFID tag 11, and the arrangement position P8 is not set as the arrangement position previously approached in S111, the control unit 65 of the automatic guided vehicle 30 determines that the arrangement position P1 of the first RFID tag 11 is the arrangement position P1 (S105 "Yes"), determines that the arrangement position previously approached is not the initial position P0 (S106 "No"), and determines that the arrangement position previously approached is not the initial position P0. It is also determined that the AGV 30 is not at the parking position P8 ("No" in S112), and in this case, since the operation command for the abnormality determined in S104, i.e., the operation command for the abnormality read from the RFID tag 11 by the RFID reader 34, is "turn right 90 degrees, travel straight for two seconds, and stop," the driving of the travel drive motors 61 of the drive wheels 32 of the traveling unit 36 ​​is controlled to make the AGV 30 turn right, travel straight for two seconds, and then stop (S114), and the AGV 30 is caused to leave the traveling line 10 to the inside (S115). After this, the control procedure shown in FIG. 9 ends.

[0076] As described above, in the automated guided vehicle traveling system Sy of this embodiment, when the automated guided vehicle 30 approaches any of the RFID tags 11 to 18, the control unit 65 of the automated guided vehicle 30 determines the arrangement position of the approached RFID tag read by the RFID reader 34, determines whether the arrangement position of the approached RFID tag is the arrangement position next to the arrangement position of another RFID tag that was previously approached, and if it determines that it is the next arrangement position, executes the normal operation command read by the RFID reader 34 from the approached RFID tag, and if it determines that it is not the next arrangement position, executes the abnormal operation command read by the RFID reader 34 from the approached RFID tag, and makes the automated guided vehicle 30 make a 90-degree right turn or a 90-degree left turn, travels straight for two seconds, stops, and causes the automated guided vehicle 30 to leave the traveling line 10. Therefore, an unmanned transport vehicle 30 that is operating abnormally will not stop on the travel line 10 and hinder the travel of other unmanned transport vehicles 30, so that the other following unmanned transport vehicles 30 can continue to travel and work normally.

[0077] In the above embodiment, the unmanned guided vehicle 30 is caused to move forward, backward, turn right, and turn left by controlling the rotational speed and rotational direction of each of the multiple drive wheels 32. However, it is also possible to provide separate drive wheels and steering wheels, and to change the running speed of the unmanned guided vehicle 30 by controlling the rotational speed and rotational direction of the drive wheels, and to switch between forward and reverse movement, and to change the direction of the steering wheels to change the traveling direction of the unmanned guided vehicle 30.

[0078] In addition, the working section 37 of the unmanned transport vehicle 30 is provided with arms 42 that move the case CS in and out of the receiving position LP and the sending position UP, but instead of the arms 42, robot arms or the like may be provided at the receiving position LP and the sending position UP to move the case CS in and out of the working section 37.

[0079] Furthermore, the configuration and processing of the embodiment described above with reference to FIGS. 1 to 9 are merely one embodiment of the present invention, and the present invention is not limited to these configurations and processing.

Claims

1. A system comprising: a travel line laid on a road surface; an unmanned guided vehicle that travels along said travel line; and a plurality of RFID tags that are sequentially arranged along said travel line and that store an arrangement position along said travel line, an operation command for said unmanned guided vehicle under normal circumstances, and an operation command for said unmanned guided vehicle under abnormal circumstances, said unmanned guided vehicle having: an RFID reader that reads the RFID tag that it approaches each time it approaches each RFID tag as it travels along said travel line; a control unit that, when the unmanned guided vehicle approaches any of the RFID tags, determines the arrangement position of the approaching RFID tag read by the RFID reader, determines whether the arrangement position of the approaching RFID tag is the arrangement position next to the arrangement position of another RFID tag that was previously approached, and if it is determined that it is the next arrangement position, executes the normal operation command read from the approaching RFID tag by the RFID reader, and if it is determined that it is not the next arrangement position, executes the abnormal operation command read from the approaching RFID tag by the RFID reader.

2. The automated guided vehicle travel system according to claim 1, wherein the operation command in the event of an abnormality indicates travel to a position away from the travel line.

3. The automated guided vehicle travel system according to claim 2, wherein the automated guided vehicle is equipped with a steering and traveling unit that changes the direction of the automated guided vehicle and causes the automated guided vehicle to travel or stop, and the control unit controls the steering and traveling unit in response to an operation command in the event of an abnormality to change the direction of the automated guided vehicle and cause the automated guided vehicle to travel to a position away from the travel line and stop.

4. The automated guided vehicle traveling system of claim 1, wherein when the control unit determines that the arrangement position of the approaching RFID tag is the initial arrangement position at which the traveling started, if the arrangement position of the previously approaching RFID tag is not the predetermined initial position but the predetermined final arrangement position, the control unit controls the traveling drive motor of the automated guided vehicle to stop the automated guided vehicle at a predetermined standby position.

5. The automated guided vehicle travel system according to claim 1, wherein a plurality of automated guided vehicles are provided to travel along the travel line.

6. A method for running an unmanned guided vehicle, comprising the steps of: each time an unmanned guided vehicle running along a line laid on a road surface approaches a plurality of RFID tags arranged in sequence along the line of travel, reading from the approaching RFID tag by an RFID reader provided on the unmanned guided vehicle the arrangement position of the RFID tag along the line of travel, and normal operation commands and abnormal operation commands for the unmanned guided vehicle; and when the unmanned guided vehicle approaches any of the RFID tags, determining the arrangement position of the approaching RFID tag read by the RFID reader, determining whether the arrangement position of the approaching RFID tag is the arrangement position next to the arrangement position of another RFID tag that the unmanned guided vehicle approached last time, and if it is determined that the arrangement position is the next arrangement position, executing the normal operation command read from the approaching RFID tag by the RFID reader, and if it is determined that the arrangement position is not the next arrangement position, executing the abnormal operation command read from the approaching RFID tag by the RFID reader.

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