Automatic conveying device and automatic conveying method

Abstract

To eliminate torsion of wiring without lowering work efficiency when conveying a truck in a form of being connected to an automatic conveying vehicle through a connecting shaft.SOLUTION: An automatic conveying device 10 includes: at least one automatic conveying vehicle 11, 12; a truck 13 connected to the automatic conveying vehicles 11, 12; connecting shafts 14, 15 that extend in a vertical direction and connect the automatic conveying vehicles 11, 12 and the truck 13; and control sections 16, 17 that can control the automatic conveying vehicles 11, 12. The automatic conveying vehicles 11, 12 are configured to be able to turn around the connecting shafts 14, 15 with respect to the truck 13. Each of the connecting shafts 14, 15 is provided with an elastic member 28 to receive vertical load from the truck 13 side and compression amount adjustment means 29 capable of adjusting a compression amount in the vertical direction of the elastic member 28. The compression amount of the elastic member 28 is adjusted so that the automatic conveying vehicles 11, 12 can turn around the connecting shafts 14, 15 while maintaining a stop state of the truck 13 when the automatic conveying vehicles 11, 12 stop traveling.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an automatic transfer device and an automatic transfer method. [Background technology]

[0002] 2. Description of the Related Art In production sites such as factories, automatic guided vehicles (AGVs, also called unmanned guided vehicles) are used to transport parts, intermediate products, or finished products in order to improve productivity by saving labor.

[0003] Furthermore, when carrying out the above-mentioned automatic transport, there are known methods in which a cart loaded with parts is towed by one automatic transport vehicle (see Patent Document 1), and methods in which the object to be transported is transported by two automatic transport vehicles (see Patent Document 2).

[0004] In this type of automatic transport device, a battery, a control device, etc. are provided on the side of the carriage, and these batteries and control devices are electrically connected to the drive unit (motor, etc.) of the automatic transport vehicle via a harness. Therefore, for example, if the automatic transport vehicle is made to repeatedly turn in an attempt to change the direction (attitude) of the carriage, the harness may become twisted and, in some cases, may break.

[0005] Here, Patent Document 3 proposes a method of determining whether or not the harness has been twisted by a predetermined amount or more based on the angular difference between the AGV body and the drive unit, and if it is determined that the harness has been twisted by a predetermined amount or more, providing a line segment on the AGV's route that can move back and forth, and causing the AGV to move back and forth on that line segment, thereby eliminating the twist. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4877520 [Patent Document 2] Patent No. 6151159 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-199370 Summary of the Invention [Problem to be solved by the invention]

[0007] However, with the above-mentioned method, the automated guided vehicle needs to move back and forth along a specific line segment set on the route to remove the twist in the wiring. This movement is far removed from the original movement of transporting the load on the cart to the specified position, and is therefore a wasteful movement. Furthermore, this wasteful movement leads to a decrease in work efficiency.

[0008] The above-mentioned problem is not limited to a transport system in which two automated guided vehicles are connected, but can also occur when a transport system in which one or three or more automated guided vehicles are connected is used.

[0009] In view of the above circumstances, the technical problem to be solved in this specification is to be able to eliminate twists in the wiring without reducing work efficiency when transporting a cart connected to an automatic guided vehicle via a connecting shaft. [Means for solving the problem]

[0010] The above-mentioned problems are solved by an automatic guided vehicle according to the present invention. That is, this automatic guided vehicle includes at least one automatic guided vehicle capable of traveling on a predetermined route, a carriage connected to the automatic guided vehicle, a connecting shaft extending vertically and connecting the automatic guided vehicle to the carriage, and a control unit capable of controlling the automatic guided vehicle, with wiring extending from the automatic guided vehicle to the carriage, the automatic guided vehicle being configured to be rotatable relative to the carriage about the connecting shaft, the connecting shaft being provided with an elastic member that receives a vertical load from the carriage and a compression amount adjustment means that is provided with an adjustment means for adjusting the amount of vertical compression of the elastic member, and the amount of compression of the elastic member is adjusted so that the automatic guided vehicle can rotate about the connecting shaft while maintaining the carriage stopped when the automatic guided vehicle is stopped.

[0011] As described above, by providing an elastic member on the connecting shaft connecting the automated guided vehicle and the carriage, which receives a vertical load from the carriage, the load that the automated guided vehicle receives from the carriage can be reduced. Therefore, when the automated guided vehicle stops traveling, the compression amount of the elastic member can be adjusted to an extent that the automated guided vehicle can rotate about the connecting shaft while maintaining the carriage in a stopped state. For example, when the automated guided vehicle stops traveling (traveling) and an operation is performed to unload (transport) an item on the carriage, the automated guided vehicle alone can rotate about the connecting shaft. Therefore, for example, if a predetermined twist occurs in the wiring between the automated guided vehicle and the carriage while the automated guided vehicle is traveling along a predetermined route, the twist can be eliminated by rotating the automated guided vehicle in a direction that is expected to eliminate the twist while the operation is being performed along the route.

[0012] In addition, the automatic transport device according to the present invention may further include a phase acquisition unit capable of acquiring the phase of the automatic transport vehicle around the connecting axis relative to the carriage, and the control unit may control the rotation of the automatic transport vehicle around the connecting axis based on the phase value acquired by the phase acquisition unit when the automatic transport vehicle stops traveling.

[0013] By providing a phase acquisition unit in this way, it is possible to know the change in phase during transportation (travel). Since twists in the wiring occur due to a series of predetermined turning operations while the automated guided vehicle is traveling, such as operations that deviate from the predetermined route, if the change in phase during travel can be accurately known, the amount of twist in the wiring can be accurately evaluated. If the amount of twist can be accurately evaluated, it becomes possible to completely eliminate the twist by turning the automated guided vehicle on the spot in a direction that will eliminate the twist by the amount of twist.

[0014] Furthermore, in the automatic conveying device according to the present invention, when the above-mentioned phase acquisition unit is provided, the control unit may control the amount of rotation of the automatic conveying vehicle so that, when the phase is set to zero when there is no twist in the wiring, the phase becomes zero when the automatic conveying vehicle stops moving.

[0015] In this way, by setting the phase to zero when there is no twist in the wiring, the phase value acquired by the phase acquisition unit can be regarded as the amount of twist (torsion angle) of the wiring. This allows the amount of twist in the wiring to be evaluated more accurately, so by giving the automated guided vehicle a turning motion in the opposite direction with the same magnitude as the evaluated amount of twist, it becomes possible to completely and reliably eliminate twists in the wiring.

[0016] The automatic guided transport device according to the present invention may also be an automatic guided transport device in which one automatic guided vehicle is connected to each of the front and rear sides of a carriage via a connecting shaft, and these two automatic guided vehicles can transport an object on the carriage through cooperation of each other. In this case, the control unit may control the two automatic guided vehicles to turn about the connecting shaft in the same direction and at the same time when viewed from above.

[0017] In this way, even when two automated guided vehicles are coupled to the front and rear of a carriage and can transport loads on the carriages through their cooperation, by providing elastic members on the connecting shafts connecting each automated guided vehicle to the carriage and adjusting the compression amount of these elastic members to an appropriate size, the two automated guided vehicles can be rotated around their respective connecting shafts while the carriages are kept stationary. Furthermore, considering that twists in the wiring between both automated guided vehicles and the carriages may occur in the same direction as the transport operation continues, by rotating the two automated guided vehicles in the same direction, the twists in the wiring on both sides can be eliminated with a single rotation. Furthermore, by performing the rotation operations of both automated guided vehicles at the same time, the forces acting on the carriages during the rotation operations can be offset, making it possible to more reliably eliminate twists in the wiring while keeping the carriages stationary.

[0018] The above-mentioned problems are also solved by an automatic transport method using the automatic transport device according to the present invention. That is, this automatic transport method is an automatic transport method in which at least one automatic transport vehicle, the carriage of which is connected via a connecting shaft extending in the vertical direction, is made to travel along a predetermined route, thereby making it possible to transport an object mounted on the carriage, the connecting shaft being provided with an elastic member that receives a vertical load from the carriage, and a compression amount adjustment means that is capable of adjusting the amount of vertical compression of the elastic member, and when the automatic transport vehicle stops traveling, the compression amount adjustment means adjusts the amount of compression of the elastic member, thereby rotating the automatic transport vehicle about the connecting shaft while maintaining the carriage in a stopped state, thereby eliminating twists that have occurred in wiring spanning from the automatic transport vehicle to the carriage.

[0019] Thus, with the automatic transport method according to the present invention, by providing an elastic member on the connecting shaft connecting the automatic transport vehicle and the carriage, which receives a vertical load from the carriage, it is possible to reduce the load that the automatic transport vehicle receives from the carriage. As a result, when the automatic transport vehicle stops traveling, the compression amount of the elastic member can be adjusted to an extent that the automatic transport vehicle can rotate about the connecting shaft while maintaining the carriage in a stopped state. For example, while the load on the carriage is being unloaded, if a predetermined twist occurs in the wiring between the automatic transport vehicle and the carriage while the automatic transport vehicle is transporting along a predetermined route, the twist in the wiring can be eliminated by rotating the automatic transport vehicle in a direction that is expected to eliminate the twist. [Effects of the Invention]

[0020] As described above, according to the automatic conveying device and automatic conveying method of the present invention, when conveying a cart connected to an automatic conveying vehicle via a connecting shaft, it is possible to eliminate twists in the wiring without reducing work efficiency. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a plan view of an automatic conveying device according to an embodiment of the present invention. [Figure 2]FIG. 2 is a cross-sectional view of a main part of the automatic conveying device shown in FIG. [Figure 3] 2 is a plan view showing an example of a transfer path and an arrangement of each process on the transfer path according to an example of an automatic transfer method using the automatic transfer device shown in FIG. 1. FIG. [Figure 4] 4 is a graph conceptually showing a history of fluctuations in the amount of twist of the wire when the wire travels around the transfer path shown in FIG. 3. [Figure 5] 4 is an enlarged plan view of a main part for explaining the operation of each automated guided vehicle in the direction changing process shown in FIG. 3. FIG. [Figure 6] 4 is an enlarged plan view of a main part for explaining the operation of each automated guided vehicle in the unloading process shown in FIG. 3. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An automatic conveying device according to an embodiment of the present invention and an automatic conveying method using this conveying device will be described below with reference to the accompanying drawings.

[0023] 1 shows a plan view of an automatic guided vehicle 10 according to one embodiment of the present invention. This automatic guided vehicle 10 mainly comprises two automatic guided vehicles 11 and 12, a carriage 13 to which the two automatic guided vehicles 11 and 12 are connected, connecting shafts 14 and 15 that connect each of the automatic guided vehicles 11 and 12 to the carriage 13, and control units 16 and 17 that control each of the automatic guided vehicles 11 and 12.

[0024] The carriage 13 has a rectangular shape in plan view as shown in the figure, and is capable of carrying an object to be transported, such as an automobile body (not shown). The carriage 13 has a plurality of free wheels 18 and is configured to be rotatable about a vertical axis. This allows the carriage 13 to move in all directions in a planar direction in accordance with both automatic guided vehicles 11 and 12.

[0025] In this embodiment, the carriage 13 is provided with protrusions 19 and 20 at one end and the other end in the front-rear direction (here meaning the direction along the traveling direction of the automated guided vehicles 11 and 12), and these protrusions 19 and 20 are connected to the front and rear automated guided vehicles 11 and 12 via connecting shafts 14 and 15, respectively. The structure around the connecting shafts 14 and 15 will be described later.

[0026] Each of the automated guided vehicles 11 and 12 has a structure capable of automatically traveling along a predetermined path L (see FIG. 3 described later). For example, the automated guided vehicles 11 and 12 have a pair of wheels 21 and 22 and a pair of drive sources 23 and 24 that apply rotational driving force to each of the wheels 21 and 22. In this case, the automated guided vehicles 11 and 12 can travel straight by rotating the wheels 21 and 22 in the same direction at the same rotation speed. Alternatively, by rotating the wheels 21 and 22 in the same direction but at different rotation speeds, the automated guided vehicles 11 and 12 can travel (forward or backward) while turning toward the wheel with the lower rotation speed of each pair of wheels 21 and 21 (22 and 22). As described above, each of the automated guided vehicles 11 and 12 travels, and these two automated guided vehicles 11 and 12 travel in cooperation with each other, thereby transporting the carriage 13 and the load on the carriage 13. In this embodiment, a connecting shaft 14 (15) is disposed between each pair of wheels 21 and 21 (22 and 22). Therefore, as will be described later, by rotating the wheels 21 and 22 in opposite directions at the same rotation speed, the automated guided vehicles 11 and 12 can turn around the connecting shafts 14 and 15 relative to the carriage 13.

[0027] Next, the structure around the connecting shaft 14 that connects the one automated guided vehicle 11 and the carriage 13 will be described in detail.

[0028] 2 shows a cross-sectional structure of the connecting shaft 14 between one automated guided vehicle 11 and the carriage 13 and its surroundings. As shown in this figure, the connecting shaft 14 is fixed to either one of the automated guided vehicle 11 or the carriage 13, and is supported by the other so as to be rotatable around the connecting shaft 14. In this embodiment, the lower end 14a of the connecting shaft 14 is fitted and fixed to a support 26 installed on a base plate 25 of one automated guided vehicle 11.

[0029] Furthermore, a sliding bearing 27 that can be fitted onto the upper end 14b of the connecting shaft 14 is attached to the tip of the protrusion 19 located on the front side of the cart 13. Therefore, by fitting the sliding bearing 27 onto the connecting shaft 14 that is fitted and fixed to the support body 26, the cart 13 is able to rotate around the connecting shaft 14 relative to the automated guided vehicle 11. Note that even when the cart 13 and the automated guided vehicles 11 and 12 rotate to a position where they overlap in a plan view (for example, the cart 13 and the automated guided vehicle 12 in FIG. 1), one is designed to be higher (lower) overall than the other so that they do not interfere with each other. In this embodiment, each of the automated guided vehicles 11 and 12 is designed to be lower overall than the cart 13.

[0030] The connecting shaft 14 is provided at its axially intermediate position with a large-diameter portion 14c having a larger outer diameter than the upper end portion 14b, which is fitted to the plain bearing 27. An elastic member 28 is disposed between the large-diameter portion 14c and the plain bearing 27, covering the outer periphery of the connecting shaft 14. The upper side of the elastic member 28 abuts against the plain bearing 27 in the axial direction, and the lower side of the elastic member 28 abuts against the large-diameter portion 14c in the axial direction. The elastic member 28 is provided with a compression amount adjustment mechanism 29 that can adjust the amount of axial compression of the elastic member 28. In this embodiment, the compression amount adjustment mechanism 29 is composed of a flange of the plain bearing 27 and a push screw 30 that can push the plain bearing 27 downward by tightening it axially between the flange and the protrusion 19 that abuts against the flange in the axial direction. Therefore, the compression amount of the elastic member 28 can be adjusted by adjusting the amount of downward compression of the plain bearing 27 using the compression amount adjustment mechanism 29 configured as described above. As the elastic member 28, a known mechanical element such as a compression spring can be used.

[0031] Here, the compression amount of elastic member 28 is adjusted so that when automated guided vehicle 11 stops traveling, automated guided vehicle 11 can turn around connecting shaft 14 while cart 13 is maintained in a stopped state. More preferably, the compression amount of elastic member 28 is adjusted so that when automated guided vehicle 11 is traveling, cart 13 smoothly follows automated guided vehicle 11 while turning around connecting shaft 14, and when automated guided vehicle 11 stops traveling, automated guided vehicle 11 can turn around connecting shaft 14 relative to cart 13 while maintaining the stopped state of cart 13.

[0032] Although not shown in the figure, the connecting shaft 15 and its surroundings that connects the other automatic guided vehicle 12 and the cart 13 on the rear side of the cart 13 are also provided with a structure similar to that of the connecting shaft 14, i.e., an elastic member and a means for adjusting the compression amount thereof, and when the automatic guided vehicle 12 stops moving, the compression amount of the elastic member is adjusted so that the automatic guided vehicle 12 can rotate around the connecting shaft 15 while maintaining the cart 13 in a stopped state.

[0033] Furthermore, each automated guided vehicle 11, 12 is provided with phase measurement units 31, 32 as phase acquisition units capable of measuring the phase of each automated guided vehicle 11, 12 relative to the bogie 13 around connecting shafts 14, 15. In this embodiment, the phase of each automated guided vehicle 11, 12 relative to the bogie 13 around connecting shafts 14, 15 can be measured by detecting the circumferential positions of phase measurement plates 33, 34 attached to the side of the bogie 13. In this case, for example, if there is no twist in the wiring from each automated guided vehicle 11, 12 to the bogie 13, reference values ​​are set so that the phases θ1, θ2 of each automated guided vehicle 11, 12 traveling on a straight path L relative to the bogie 13 about connecting shafts 14, 15 are zero. In this embodiment, an example is given in which the phase measurement units 31, 32 are provided on the side of the automatic guided vehicles 11, 12, and the object to be measured (phase measurement plates 33, 34) is provided on the side of the carriage 13, but it is of course also possible to provide the phase measurement units 31, 32 on the side of the carriage 13, and the phase measurement plates 33, 34 on the side of the automatic guided vehicles 11, 12.

[0034] Each control unit 16, 17 is capable of controlling various operations, including the travel of the corresponding automated guided vehicles 11, 12. First, the control mode during travel will be described. Each automated guided vehicle 11, 12 is provided with a path detection unit (not shown) capable of detecting path L, and is configured to be able to control the movement of each automated guided vehicle 11, 12 so that each automated guided vehicle 11, 12 is positioned on path L (without deviating from path L) based on position information regarding path L detected by this path detection unit. Specifically, each control unit 16 (17) is configured to be able to control the rotation speed and the difference in rotation speed of each pair of wheels 21, 21 (22, 22) so as to satisfy the above-mentioned conditions.

[0035] Furthermore, under predetermined conditions, each control unit 16, 17 controls the movement of the front automated guided vehicle 11(12) so that the front automated guided vehicle 11(12) is always positioned on the path L, and can also control the movement of the rear automated guided vehicle 12(11) so that the rear automated guided vehicle 12(11) moves toward a position off the path L. In this case, the specific control mode is, in principle, arbitrary. For example, it is possible to control the speed and phase θ2 of the rear automated guided vehicle 12 based on the phase θ1 of the front automated guided vehicle 11. Because the distance between the connecting shafts 14, 15 is constant, the relative position of the rear automated guided vehicle 12(11) that has deviated from the path L can be calculated based on the phases θ1, θ2 of the respective automated guided vehicles 11, 12, and thereby control the position of the rear automated guided vehicle 12(11).

[0036] Next, an example of an automatic transfer method using the automatic transfer device 10 configured as described above, particularly an automatic transfer method including an operation for eliminating twists in the wiring, will be described together with the effects of the present invention.

[0037] In the automatic conveying method according to this embodiment, as shown in Fig. 3, two automatic guided vehicles 11, 12 travel in cooperation on a route L forming a predetermined closed loop, and an object on a carriage 13 connected between the two automatic guided vehicles 11, 12 is automatically conveyed along the route L. In this case, the route L is provided with a step of loading the object (loading step S1), a step of turning over the carriage 13 with the object loaded thereon (left-right turning step S2), and a step of unloading the object (unloading step S3), and predetermined operations are performed in each of the steps S1 to S3. For example, in the left-right turning step S2, the posture of the carriage 13 is turned over left-right, and so left and right doors are attached to the automobile body on one side (e.g., the outside) of the route L.

[0038] During the above-described automatic transport, the phases θ1 and θ2 of the automatic transport vehicles 11 and 12 relative to the carriage 13 are continuously measured by the phase measuring units 31 and 32 provided on the automatic transport vehicles 11 and 12, respectively.

[0039] First, each control unit 16, 17 controls the travel of the corresponding two automated guided vehicles 11, 12 so that the two automated guided vehicles 11, 12 travel in a state where they are connected to each other via the carriage 13 on the path L (empty-car travel path L2) from the unloading process S3 to the loading process S1. Then, when the leading automated guided vehicle 11 (12) reaches a predetermined position P2 on the path L within the loading process S1, the travel of each automated guided vehicle 11, 12 is stopped, and the carriage 13 is stopped at a predetermined position within the loading process S1. When the carriage 13 stops, a predetermined load (for example, an automobile body) is loaded, and each automated guided vehicle 11, 12 resumes traveling along the path L.

[0040] During the above-described traveling, the phases θ1, θ2 of each automated guided vehicle 11, 12 temporarily change, for example, in a curved section of route L; in other words, the wiring from each automated guided vehicle 11, 12 to the carriage 13 becomes temporarily twisted; however, once both automated guided vehicles 11, 12 pass through the curved section, they return to their original state (see the fluctuation history from position P1 to position P2 in Figure 4).

[0041] Then, when the front automated guided vehicle 11 (12) reaches a predetermined position P3 on the path L (loading transport path L1) in the left-right reversal process S2, the front and rear automated guided vehicles 11, 12 are made to perform different operations to swap the positions of the front and rear automated guided vehicles 11, 12, thereby reversing the orientation of the carriage 13 left-right. Specifically, as shown in FIG. 5(a), first, from a state in which the front and rear automated guided vehicles 11, 12 are both positioned on the path L (L1), the rear automated guided vehicle 12 is moved while turning in a direction deviating from the path L to one of the left and right sides. At this time, for example, as described above, the speed and phase θ2 of the rear automated guided vehicle 12 are controlled based on the phase θ1 of the front automated guided vehicle 11 relative to the carriage 13, thereby moving the rear automated guided vehicle 12 while maintaining a constant distance between the connecting shafts 14, 15. Here, the rear automated guided vehicle 12 is moved to a position parallel to the front automated guided vehicle 11 (the position shown by the two-dot chain line in Figure 5(a)). The rear automated guided vehicle 12 is also moved so that its posture after the movement is the same as its posture before the movement. As a result, the rear automated guided vehicle 12 is rotated 90 degrees (1 / 2 x π) clockwise relative to the carriage 13. This operation also changes the posture of the carriage 13 to a state where it is rotated 90 degrees clockwise with the connecting shaft 14 as the reference. As a result of the above operation, the wiring extending from each of the automated guided vehicles 11, 12 to the carriage 13 is twisted by the increase in each phase θ1, θ2.

[0042] After that, the rear automated guided vehicle 12 is moved to a position on the path L that is forward of the front automated guided vehicle 11 (see FIG. 5(b)). At this time, the automated guided vehicle 12 is also moved so that the posture of the automated guided vehicle 12 is the same before and after the movement. As a result, the rear automated guided vehicle 12 is rotated another 90 degrees clockwise relative to the carriage 13. This operation also changes the posture of the carriage 13 so that it is rotated another 90 degrees clockwise with the connecting shaft 14 as the reference. In this way, the orientation of the carriage 13 is reversed left and right. Furthermore, the above operation causes the wiring from each of the automated guided vehicles 11 and 12 to the carriage 13 to be further twisted by the increase in each phase θ1, θ2. Therefore, it is estimated that the amount of twist in the wiring has reached 180 degrees (π) at this stage (see the fluctuation history from position P3 onwards in FIG. 4).

[0043] The twist in the wiring described above remains unresolved as the carriage 13 travels along the path L. Therefore, for example, if the carriage 13 goes around the path L once and then performs a left-right reversal operation again in the left-right reversal step S2, the twist in the wiring described above accumulates (see the fluctuation history from the second position P3 onward in FIG. 4). In this illustrated example, the amount of twist in the wiring reaches (or is presumed to reach) 360 degrees after the carriage 13 goes around the path L twice and performs the left-right reversal step S2 twice.

[0044] When the amount of twist in the wiring reaches a certain level in this way, the twist in the wiring is undone in the unloading process S3. Specifically, when the values ​​of the phases θ1 and θ2 measured by the phase measuring units 31 and 32 reach 360 degrees (2×π), when the front automated guided vehicle 11 (which has been reversed left and right twice and has returned to its original front-to-back position) reaches a predetermined position P1 on the path L in the unloading process S3, both automated guided vehicles 11 and 12 stop traveling, and the cart 13 is stopped at a predetermined position in the unloading process S3. When the cart 13 stops, the predetermined load (for example, an automobile body with parts such as doors attached) is carried out.

[0045] Furthermore, while the load is being removed from the carriage 13 as described above, any twists that have occurred in the wiring from each of the automated guided vehicles 11, 12 to the carriage 13 are eliminated. Specifically, the left and right wheels 21, 21 (22, 22) of each automated guided vehicle 11 (12) that is stopped are rotated in opposite directions, so that each automated guided vehicle 11, 12 is rotated around the connecting shafts 14, 15 relative to the carriage 13 in a direction that will eliminate the twists (counterclockwise in FIG. 6). At this time, the amount of rotation of each automated guided vehicle 11, 12 is controlled so that the values ​​of the phases θ1, θ2 measured by the phase measuring units 31, 32 become zero. As a result, any twists that have occurred in the wiring are eliminated during the unloading operation (see the fluctuation history from the third position P1 onwards in FIG. 4).

[0046] Furthermore, in the automated guided vehicle 10 according to this embodiment, the connecting shafts 14, 15 connecting the automated guided vehicles 11, 12 and the carriage 13 are provided with elastic members 28 that receive a vertical load from the carriage 13, thereby reducing the load that the automated guided vehicles 11, 12 receive from the carriage 13. Therefore, during the above-described unloading step S3 (when the automated guided vehicles 11, 12 are stopped), the compression amount of the elastic members 28 is adjusted to an extent that the automated guided vehicles 11, 12 can rotate about the connecting shafts 14, 15 while the carriage 13 is kept stopped, thereby allowing only the automated guided vehicles 11, 12 to rotate about the connecting shafts 14, 15 while unloading. Therefore, by rotating each automated guided vehicle 11, 12 in the above-described direction when twists have accumulated in the wiring between the automated guided vehicles 11, 12 and the carriage 13 as described above, it becomes possible to perform the unloading operation and the operation to untwist the wiring in parallel without moving the carriage 13.

[0047] Furthermore, by rotating the two automated guided vehicles 11 and 12 in the same direction (counterclockwise in FIG. 6) during the twist elimination operation described above, the twists in the wiring on both sides can be eliminated with a single turning operation. Furthermore, by performing the turning operations of both automated guided vehicles 11 and 12 described above at the same timing, the forces acting on carriage 13 during the turning operations can be offset, making it possible to more reliably eliminate the twists in the wiring while maintaining carriage 13 in a stopped state.

[0048] The above describes one embodiment of the present invention, but the automatic conveying device according to the present invention and the automatic conveying method using this conveying device can also have configurations other than those described above, as long as they do not deviate from the spirit of the invention.

[0049] For example, in the above embodiment, when the values ​​of the phases θ1 and θ2 measured by the phase measuring units 31 and 32 reach a predetermined value (e.g., 360 degrees), the twist elimination operation as described above is performed in the unloading process S3. However, other conditions may be used as triggers to control the twist elimination operation. For example, when the automated guided vehicles 11 and 12 travel around the closed-loop route L as shown in Fig. 3, taking into account the amount of twist in the wiring that is expected to occur per revolution, when the automated guided vehicles 11 and 12 have traveled the number of revolutions that are expected to cause the amount of twist to reach an integral multiple of 360 degrees for the first time and have detected, by tag detection or the like, that they have reached the predetermined position P1 in the unloading process S3, the detection signal may be used as a trigger to perform the twist elimination operation described above.

[0050] Furthermore, in the above embodiment, the two automated guided vehicles 11, 12 are rotated around the connecting shafts 14, 15 at the same time in a predetermined direction (a direction in which the twist is eliminated), but of course this is not limited to this. For example, the timing of the rotation operation to eliminate the twist described above may be made different for one automated guided vehicle 11 and the other automated guided vehicle 12 based on various conditions related to the unloading operation, such as the position of the center of gravity of the loaded object. The same applies to the speed (rotation speed) at that time; one automated guided vehicle 11 and the other automated guided vehicle 12 may be rotated at the same speed, or may be set to an appropriate speed based on various conditions.

[0051] Furthermore, with regard to the connection form between the carriage 13 and the connecting shafts 14, 15, the above embodiment illustrates a case in which protrusions 19, 20 are provided protruding from the carriage 13 on one side and the other side in the planar direction, and these protrusions 19, 20 and the automated guided vehicles 11, 12 are connected to each other by connecting shafts 14, 15 whose longitudinal direction is vertical, but of course other configurations are also possible. For example, although not shown, it is also possible to omit the protrusions 19, 20 of the carriage 13 and connect a frame that forms the periphery of the carriage 13 to parts of the automated guided vehicles 11, 12 that are positioned below this frame to each other by connecting shafts 14, 15.

[0052] In the above explanation, the present invention is applied to an automatic guided vehicle 10 in which two automatic guided vehicles 11, 12 are connected to each other via a carriage 13, but of course the present invention is not limited to this. For example, although not shown in the drawings, the present invention can also be applied to an automatic guided vehicle in which a carriage 13 is connected to one automatic guided vehicle via a connecting shaft, or an automatic guided vehicle in which a carriage 13 is connected to three or more automatic guided vehicles via connecting shafts. [Explanation of symbols]

[0053] 10 Automatic transport device 11,12 Automated guided vehicles 13 Cart 14,15 Connecting shaft 14a Lower end 14b Upper end 14c Large diameter section 16,17 Control section 18 Freewheel 19,20 Protrusion 21,22 wheels 23,24 Drive source 25 boards 26 Support 27 Bearings 28 Elastic member 29 Compression amount adjustment means 31,32 Phase measurement section 33,34 Phase measurement plate L route S1 installation process S2 Left / right reversal process S3 process θ1,θ2 phase

Claims

1. At least one automated guided vehicle capable of traveling along a predetermined route; a carriage coupled to the automated guided vehicle; a connecting shaft extending in a vertical direction and connecting the automated guided vehicle and the carriage; a control unit capable of controlling the automatic guided vehicle, and wiring extending from the automatic guided vehicle to the carriage; the automated guided vehicle is configured to be rotatable around the connecting shaft relative to the carriage, the connecting shaft is provided with an elastic member that receives a vertical load from the carriage side, and is also provided with a compression amount adjustment means that can adjust the amount of compression of the elastic member in the vertical direction; an automatic transport device in which the compression amount of the elastic member is adjusted so that the automatic transport vehicle can rotate around the connecting shaft while maintaining the carriage in a stopped state when the automatic transport vehicle stops traveling.

2. a phase acquisition unit capable of acquiring a phase of the automated guided vehicle relative to the carriage about the connecting shaft, The automatic guided vehicle according to claim 1 , wherein the control unit controls the rotation of the automatic guided vehicle about the connecting shaft based on the phase value acquired by the phase acquisition unit when the automatic guided vehicle stops traveling.

3. 3. The automatic transport device according to claim 2, wherein the control unit controls the amount of rotation of the automatic transport vehicle so that, when the phase is zero when there is no twist in the wiring, the phase becomes zero when the automatic transport vehicle stops traveling.

4. an automatic transport device in which one automatic transport vehicle is connected to each of the front and rear sides of the carriage via the connecting shaft, and an object mounted on the carriage can be transported by cooperation of the two automatic transport vehicles, 2. The automatic transport device according to claim 1, wherein the control unit controls the two automatic transport vehicles to turn about the connecting shaft in the same direction and at the same timing when viewed from above.

5. An automatic transport method for transporting an object mounted on at least one automatic transport vehicle, the automatic transport vehicle having a carriage connected to the carriage via a connecting shaft extending in a vertical direction, by traveling along a predetermined route, the method comprising: an elastic member that receives a vertical load from the carriage side is provided on the connecting shaft, and a compression amount adjustment means that can adjust the vertical compression amount of the elastic member is provided, When the automatic transport vehicle stops traveling, the compression amount adjustment means adjusts the compression amount of the elastic member, thereby maintaining the stopped state of the carriage and rotating the automatic transport vehicle around the connecting shaft, thereby eliminating twists in the wiring extending from the automatic transport vehicle to the carriage.

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