JPH07323944A - Unmanned transfer vehicle - Google Patents

Abstract

PURPOSE:To carry out the transfer work in an unmanned form and improve the traveling stability, even if the placing position of a cylindrical transferred substance disperses, by suspending the traveling of a car body at the point where the lengthwise center in the axis line direction of the cylindrical transferred substance nearly coincides with the center in the longitudinal direction of a lifter device, on the basis of the data detected by a sensor. CONSTITUTION:An unmanned transfer vehicle 1 stops, allowing the lengthwise center in the axis line direction of a steel plate coil 7 installed on a transfer board to nearly coincide with the center in the lengthwise direction of the load receiving board of a lifter device 8 and carries out transfer work. Accordingly, a lifter device 8 is prevented from being applied with an eccentric load, and in transfer, traveling is performed allowing the lengthwise center in the axis line direction of the steel plate coil 7 or the position of the total center of gravity to coincide with the center in the longitudinal direction of the placing boards 9 and 9. Accordingly, each traveling wheel device 3 is prevented from being applied with the eccentric load, and the load for each traveling wheel device 3 is arranged, and the imbalance of the steering load is reduced, and the traveling stability is improved, and the application of the excessive load on the driving motor, etc., of each traveling wheel device 3 and the eccentric abrasion of a tire can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automated guided vehicle for transporting a cylindrical transported object such as a steel plate coil or a papermaking coil in a production line such as an iron mill, a paper mill, a stockyard or the like.

[0002]

2. Description of the Related Art Conventionally, in a steel mill, a paper mill or the like, a cylindrical conveyed product such as a steel plate coil or a papermaking coil is often placed so that its axis is in a horizontal state. In the case of carrying a certain route on the premises for the next process or shipping as a product, it was laid on a dedicated rail car or a traveling road. It is generally transferred together with a pallet to an automated guided vehicle equipped with a sensor for detecting a derivative, and when it is carried out from a factory, it is generally transferred together with the pallet to a loading platform such as a truck.

[0003]

However, the transfer work using a crane, a ram truck, or the like is often dangerous because the weight of the transported object is large. In addition, since the transported object is transferred together with the pallet, the transported weight is increased and a large-sized transport vehicle is required. Furthermore, a large number of pallets must be prepared, and empty pallets must be transported separately.

Therefore, according to the present invention, an unmanned guided vehicle performs a transfer operation for temporarily placing a cylindrical transferred object on a transfer table without using a pallet and transferring the cylindrical transferred object to another transfer table. Although a transfer system was adopted, in this case, the cylindrical transfer object is often placed on the transfer table by a crane or the like by manual operation, so that the mounting position of the cylindrical transfer object varies widely. . However, since an automated guided vehicle generally stops at a specified position according to a stop sign on a traveling road, the mounting position of a cylindrical transported article often does not match the stopped position of the automated guided vehicle. When the work is performed, an unbalanced load acts on the automatic guided vehicle, which affects the running stability of the automatic guided vehicle.Therefore, even if there is a variation in the mounting position of the cylindrical transported object, the transfer work can be performed unattended. Moreover, it is an object of the present invention to provide an automatic guided vehicle having excellent traveling stability.

[0005]

In order to achieve the above-mentioned object, the present invention, in a first aspect of the present invention, provides a cylindrical transfer object placed on a transfer table formed in a gate shape, with the cylindrical object. A lifter device, which is arranged in the longitudinal direction of the central portion of the vehicle body, for supporting and lifting in the axial direction of the bag-like conveyed object, and a pair of mounting tables provided separately on the left and right of the lifter device, A sensor for detecting the axial length of the cylindrical conveyed object when entering the lower part of the transfer table, and the axial length center of the cylindrical conveyed object and the lifter based on the data detected by the sensor. A control device for stopping the traveling of the vehicle body at a point where the center of the device in the longitudinal direction substantially coincides,
According to the second aspect of the invention, in order to support and lift a plurality of cylindrical conveyed objects placed on a transfer table formed in a gate shape in the axial direction of the cylindrical conveyed objects, A lifter device that is arranged in the longitudinal direction and is capable of moving up and down, a pair of mounting tables that are spaced apart from each other on the left and right sides of the lifter device, and an axial length of the cylindrical object when entering the lower part of the transfer table. A sensor for detecting the height, the data detected by the sensor, and the data such as the number of the previously input cylindrical conveyed objects, the weight of the cylindrical conveyed objects, the type of the cylindrical conveyed objects, the arrangement order, and the like, A control device for stopping the traveling of the vehicle body at a point where the total center of gravity of the cylindrical conveyed product and the center of the lifter device in the longitudinal direction substantially coincide with each other, and in the third invention, the gate is provided. A plurality of cylindrical conveyed objects placed on a transfer table formed in a mold are A lifter device, which is arranged in the longitudinal direction of the central portion of the vehicle body, for supporting and lifting in the axial direction of the bag-like conveyed object, and a pair of mounting tables provided separately on the left and right of the lifter device, A sensor for detecting the axial length of the cylindrical conveyed object when entering the lower part of the transfer table, data detected by the sensor, the number of the cylindrical conveyed objects inputted in advance, and the weight of the cylindrical conveyed object. When the total center of gravity of the cylindrical conveyed object and the center of the lifter device in the longitudinal direction are made to substantially coincide with each other by calculating data such as the type and arrangement order of the cylindrical conveyed objects, the cylindrical conveyed object When any one of the end portions of the lifter device is located outside the end portion of the lifter device, the traveling of the vehicle body is performed at a point where the center of the axial length of the cylindrical conveyed product and the center of the lifter device in the longitudinal direction substantially coincide with each other. Characterized by having a control device for stopping That.

According to a fourth aspect of the present invention, in the control device according to each aspect of the invention, the sensor conveys the cylindrical article on the transfer table while the cylindrical article is mounted on the mounting table. If it is detected that the transfer table has been moved, the entrance to the lower part of the transfer table is stopped.

[0007]

[Operation] According to the above configuration, in the first aspect of the present invention, when the single or plural cylindrical objects placed on the transfer table have the same length and the same weight, the transfer object is formed in a gate shape. It travels to the lower part of the loading table, enters, and stops while making the axial length center of the cylindrical conveyed object placed on the transfer table substantially coincide with the longitudinal center of the lifter device, and lifts the lifter device. Lift the cylindrical object on the transfer table, run from the bottom of the transfer table and stop
The lifter device descends and the cylindrical object is mounted on the mounting table, travels again, and is conveyed, and once it reaches the destination, it stops once again, and the lifter device rises to lift the cylindrical object on the mounting table. And moves to the lower part of the transfer table, stops at a predetermined position, and lowers the lifter device to mount the cylindrical conveyed object on the transfer table.

According to the second aspect of the present invention, when the axial lengths of the plurality of cylindrical articles and the intervals at which they are placed on the transfer table are different from each other, the total center of gravity of the cylindrical articles is determined. The lifter device is stopped by substantially aligning it with the center of the longitudinal direction,
Raise the lifter device to pick up the cylindrical object on the transfer table, run from the bottom of the transfer table and stop for a while, then lower the lifter device to mount the cylindrical object on the mounting table and run again. Transport it, and once it reaches the destination, stop it again, raise the lifter device, lift the cylindrical object on the mounting table and enter the lower part of the transfer table, stop at a predetermined position and lower the lifter device. And place the cylindrical article on the transfer table.

According to a third aspect of the invention, the axial lengths of the plurality of cylindrical articles and the intervals at which they are placed on the transfer table are different, and the total center of gravity of the cylindrical articles and the lifter are different. When the ends of any one of the cylindrical conveyed objects are located outside the end portions of the lifter device when the longitudinal center of the apparatus is substantially aligned, the overall length of the cylindrical conveyed object in the axial direction is determined. The lifter device is lifted to pick up the cylindrical object on the transfer table, run from the lower part of the transfer table and temporarily stopped, and the lifter device is stopped. Down to mount the cylindrical object on the mounting table, travel again to carry it, and once it reaches the destination, stop it again,
The lifter device is moved up to pick up the cylindrical transported object on the mounting table to enter the lower portion of the transfer table, and stopped at a predetermined position to lower the lifter device to mount the cylindrical transported object on the transfer table.

According to a fourth aspect of the present invention, in the control device according to each aspect of the invention, the sensor is mounted on the transfer table while the sensor is mounted on the transfer table while the cylindrical object is mounted on the mounting table. When it is detected that the transfer table is located, the entry to the lower part of the transfer table is stopped. Therefore, the sensor also serves as a sensor for detecting the presence or absence and the length of the cylindrical transported object on the transfer table.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an automatic guided vehicle for carrying a steel sheet coil which is a cylindrical object will be described below with reference to the drawings.

The automated guided vehicle 1 has four traveling wheel devices 3 on the lower portion of the vehicle body 2, and a traveling sensor 4 provided on the lower central portion of the vehicle body 2 detects a dielectric 5 laid on the traveling path to automatically drive the vehicle. Since it is driven, it is configured with 4-wheel independent drive / 4-wheel independent steering, so it is possible to run forward and backward, laterally to the left and right, spin turn, and oblique in all directions. Then, the steel plate coil 7 placed on the transfer table 6 is loaded onto the upper part of the vehicle body 2 and conveyed.

For this reason, a lifter device 8 is provided on the upper part of the vehicle body 2 so as to be movable up and down in the longitudinal direction of the central portion, and a pair of mounting tables 9 are provided on the left and right sides of the lifter device 8 so as to be separated from each other.
9 are provided.

The transfer table 6 is mounted on the upper portions of both side walls 6a, 6a.
Each of the cargo receiving portions 6 is inclined and descends symmetrically toward the center line.
b, 6b is provided in a gate type, and both load receiving portions 6b, 6b
A central gap 6c is formed between them. Further, on the load receiving portions 6b, 6b, the placement center position 6d and the placement allowable range displays 6e, 6e are marked with a paint color or the like, and in principle,
The steel plate coil 7 is placed inside the placement allowable range displays 6e, 6e.

The lifter device 8 is provided with a load receiving base 8a provided in the longitudinal direction of the vehicle body and two cylinders 8b, 8 provided in front of and behind the vehicle body 2 below the load receiving base 8a.
The load receiving base 8a can be retracted from the recess 10 between the mounting bases 9 by the expansion and contraction of the cylinders 8b and 8c, and the upper surface of the load receiving base 8a descends from both sides toward the center line of the vehicle body. It has a V-shaped cross section, and also has a mounting table 9,
The reference numerals 9 respectively form inclined load receiving surfaces that descend toward the vehicle body center line on the vehicle body center side.

The loading tray 8a is provided with a cylinder 8 when the automated guided vehicle 1 enters the lower portion of the loading platform 6 on which the steel plate coil 7 is placed.
b and 8c are extended to rise from the central gap 6c of the transfer table 6, and the steel plate coil 7 mounted on the transfer table 6 is supported and lifted in the axial direction. Separate.

The automated guided vehicle 1 in which the steel plate coil 7 is lifted by the lifter device 8 runs from the lower part of the transfer table 6 and is temporarily stopped.
When the steel plate coil 7 is lowered and the steel plate coil 7 is mounted on the mounting tables 9 and 9, the steel plate coil 7 is automatically conveyed to convey the steel plate coil 7 and once the transfer table 6 at the destination is reached, the steel plate coil 7 is once again stopped and The steel plate coil 7 is lifted to lift the steel plate coil 7 on the mounting table 9 to enter the lower part of the transfer table 6, and is stopped at a predetermined position to lower the load receiving table 8a to mount the steel plate coil 7 on the transfer table 6. To do.

At the time of this transfer operation, the automatic guided vehicle 1 is based on the data previously input from the central control system 11.
The inductor 5 laid on the running path is detected by the running sensor 4 and automatically runs along the inductor 5, and the desired steel plate coil 7
The vehicle enters the lower part of the transfer table 6 on which is mounted and temporarily stops at a predetermined position according to the stop display laid on the traveling path.

However, as described above, even if the loading center position 6d and the loading allowable range indications 6e, 6e are marked on the load receiving portions 6b, 6b of the transfer table 6 with a paint color or the like, the steel plate Since the coil 7 is placed on the transfer table 6 by a manual operation of a crane or the like, the placement position thereof often varies and is not constant.

Therefore, the longitudinal center of the load receiving base 8a of the lifter device 8 of the automatic guided vehicle 1 temporarily stopped at the predetermined position does not substantially coincide with the axial center of the steel plate coil 7 on the transfer table 6. Sometimes.

When the load receiving base 8a is raised in this state, an eccentric load acts on the cylinders 8b and 8c. Although some unbalanced load can be tolerated by synchronizing the hydraulic pressures of the cylinders 8b and 8c, in principle, unbalanced load is generated in the cylinders 8b and 8c.
c is not preferable to itself and its hydraulic circuit.

Also, when the steel plate coil 7 is mounted on the mounting tables 9, 9 from the load receiving table 8a and conveyed, the mounting tables 9, 9 serving as the center of the axial length of the steel plate coil 7 and the center of the vehicle body 2 are provided.
If the center of the longitudinal direction does not substantially match, an eccentric load acts on each traveling wheel device 3, which affects traveling stability.

Therefore, the automated guided vehicle 1 is mounted on the mounting tables 9, 9
Coil detection sensors 12 are provided near the front and rear surfaces of the vehicle body 2 in the recess 10 therebetween. This coil detection sensor 12
While the automated guided vehicle 1 is entering the lower part of the transfer table 6,
The axial length between the one end and the other end of the steel plate coil 7 is detected, and this data is sent to the control device 13 mounted on the vehicle body 2. If the direction in which the automated guided vehicle 1 enters the lower part of the transfer table 6 is always constant, the coil detection sensor 12 may be provided only near one of the front and rear surfaces of the vehicle body 2.

Based on the sent data, the controller 13 permits the steel plate coil 7 to be placed if the length of the steel plate coil 7 placed on the transfer table 6 in the axial direction is larger than the length of the load receiving table 8a. When the steel plate coil 7 is placed across the range indications 6e, 6e, and the steel plate coil 7 is placed outside the placement allowable range indications 6e, 6e, an alarm indicating that the installation is impossible is issued.

Based on the sent data, the controller 13 places the steel plate coil 7 in the placement allowable range displays 6e, 6e, and the length of the steel plate coil 7 in the axial direction is greater than the length of the load receiving base 8a. When the length is short, the center of the axial length of the steel plate coil 7 is calculated, a command is issued to each traveling wheel device 3, and the automated guided vehicle 1 temporarily stopped at a predetermined position is moved forward or backward, as shown in FIG. As described above, the steel plate coil 7 is stopped at a position substantially coincident with the axial center of the load coil 8a of the lifter device 8 and the longitudinal center thereof.

When the steel plate coil 7 placed on the transfer table 6 is a single body, the longitudinal center of the load receiving table 8a of the lifter device 8 and the axial length center of the steel plate coil 7 are substantially aligned in this way. Then, since the steel plate coil 7 is supported by the load receiving table 8a, the above-mentioned transfer work can be performed without giving an unbalanced load to the cylinders 8b and 8c.

If a plurality of steel plate coils 7 mounted on the transfer table 6 have the same length and the same weight of steel plate coils 7 are mounted at equal intervals, the length of each steel plate coil 7 in the axial direction is increased. And the interval between each steel plate coil 7 is detected by the coil detection sensor 12 and data of the axial length of the entire steel plate coil 7 is sent to the control device 13, and the control device 13 causes the overall length of the steel plate coil 7 in the axial direction. A command is issued to each traveling wheel device 3 so that the center and the longitudinal center of the load receiving base 8a of the lifter device 8 substantially coincide with each other, and the automated guided vehicle 1 is stopped to perform the transfer work.

Next, when the axial lengths of the plurality of steel plate coils 7 mounted on the transfer table 6 and the intervals between the steel plate coils 7 are different, the central control system 11
From the information about the number of steel plate coils 7, the weight of each steel plate coil 7, the diameter of each steel plate coil 7 as a type, the material, the plate thickness, etc.
Data such as the arrangement order of the steel sheet coils 7 is input to the control device 13.

The control device 13 calculates the data inputted in advance, the axial length of each steel plate coil 7 detected by the coil detection sensor 12 and the data of the interval between each steel plate coil 7, and each traveling wheel device 3 To move the unmanned guided vehicle 1 temporarily stopped at a predetermined position forward or backward, and as shown in FIG. 7, the total center of gravity position of each steel plate coil 7 and the longitudinal direction of the load receiving platform 8a of the lifter device 8. The automated guided vehicle 1 is stopped at a position substantially coincident with the center to perform the transfer work.

Further, as shown in FIG. 8, when the position of the total center of gravity of each steel plate coil 7 and the center of the load carrier 8a of the lifter device 8 in the longitudinal direction are substantially aligned and stopped, the position of the total center of gravity is determined. When the end portion of the steel plate coil 7 is located outside the end portion of the load receiving base 8a of the lifter device 8 while being largely deviated from the center of the steel plate coil 7 based on the data of the entire axial length of the steel plate coil 7, The control device 13 issues a command to each traveling wheel device 3 to further advance or retreat the unmanned guided vehicle 1 so that the center of the entire length of the steel plate coil 7 in the axial direction and the center of the lifter device 8 in the longitudinal direction of the load receiving base 8a. The automated guided vehicle 1 is stopped at a position substantially coincident with.

In this case, an eccentric load acts on the cylinders 8b and 8c that move up and down the load receiving table 8a, but when the eccentric load is within the allowable range, the transfer operation is performed. However, when the unbalanced load exceeds the allowable range, or even when the entire axial center of the steel plate coil 7 and the longitudinal center of the load receiving base 8a of the lifter device 8 are made to substantially coincide with each other, the end portion of the steel plate coil 7 is lifted. When it is located outside the end of the load receiving platform 8a of the device 8, an alarm is issued without performing the transfer work.

In the control device 13, the automatic guided vehicle 1 is moved to the transfer table 6 with the steel plate coils 7 mounted on the mounting tables 9 and 9.
When the coil detecting sensor 12 detects that the steel plate coil 7 is placed on the transfer table 6 when the coil detection sensor 12 has entered the lower part, the entry to the lower part of the transfer table 6 is stopped.

As described above, the automatic guided vehicle 1 has the transfer table 6
Since the center of the axial length or the total center of gravity of the steel sheet coil 7 placed on the top and the longitudinal center of the load receiving base 8a of the lifter device 8 are substantially aligned with each other, the transfer work is performed, so that the lifter device 8 has an unbalanced load. Does not act, and during transportation, the center of the longitudinal direction of the mounting tables 9 and 9 is made to coincide with the center of the axial length of the steel plate coil 7 or the position of the total center of gravity, so that the unbalanced load is applied to each traveling wheel device 3. Does not work, the wheel weights for the traveling wheel devices 3 are averaged, and the unbalance of the steering load is reduced, so that the traveling stability is improved and the drive motor, steering motor, etc. of each traveling wheel device 3 are overloaded. Also, uneven wear of the tire is reduced, and the durability of each traveling wheel device 3 is improved.

Further, when the unmanned guided vehicle 1 in the loaded state enters the lower part of the transfer table 6 loaded, the coil detection sensor 12 detects the steel plate coil 7 on the transfer table 6 and stops the entry. Therefore, the coil detection sensor 12 functions as the presence detection, and avoids the collision between the steel sheet coils 7.

Further, since the coil detection sensor 12 can detect the presence or absence of the steel plate coil 7 on the transfer table 6 and the coil length, it is possible to detect the presence of each of the transfer tables 6 installed in a large number of production lines, stockyards, etc. It is no longer necessary to provide a sensor or coil length detection sensor and electrical wiring associated with them,
The economic effect of cost reduction is great.

[0036]

As described above, the unmanned guided vehicle of the present invention supports the cylindrical conveyed object placed on the transfer table formed in a gate shape in the axial direction of the cylindrical conveyed object. In order to lift it up and down, a lifter device which is arranged in the longitudinal direction of the central part of the vehicle body and can move up and down, a pair of mounting tables provided separately on the left and right sides of the lifter device, and enters the lower part of the transfer table. At this time, a sensor for detecting the axial length of the cylindrical conveyed object, and based on the data detected by the sensor, the axial length center or total center of gravity of the cylindrical conveyed object and the longitudinal direction of the lifter device. It is equipped with a control device that stops the traveling of the car body at a point substantially coincident with the center, travels to the lower part of the transfer table, enters, and is the center of the axial length of the cylindrical conveyed object placed on the transfer table. Alternatively, stop by making the total center of gravity position almost coincide with the center of the lifter device in the longitudinal direction and stop the lifter. Raise the device to pick up the cylindrical object on the transfer table, run from the lower part of the transfer table and stop, then lower the lifter device to mount the cylindrical object on the table and run again. Transport it, and once it reaches the destination, stop it again,
Because the lifter device is lifted to lift the cylindrical object on the mounting table to enter the lower part of the transfer table, and stopped at a predetermined position to lower the lifter device to place the cylindrical object on the transfer table. Unbalanced load does not act on the lifter device, and during transportation, the center of the axial length of the cylindrical object or the total center of gravity position is aligned with the longitudinal center of the mounting table transferred from the lifter device. Therefore, an unbalanced load does not act on each traveling wheel device, the wheel weight for each traveling wheel device is averaged, and the unbalance of the steering load is reduced, so that the traveling stability is improved and the driving of each traveling wheel device is improved. The overload on the motor, steering motor, etc. and uneven wear of the tire are reduced, and the durability of each traveling wheel device is improved.

Further, when the unmanned guided vehicle in the loaded state enters the lower part of the transfer table on which the vehicle is loaded, the sensor detects the cylindrical object on the transfer table and stops the entry. It fulfills the function of load detection and avoids collision between cylindrical objects.

Further, since the presence / absence and length of the cylindrical conveyed object on the transfer table can be detected by the sensor, the load detection sensor and the coil length are respectively set on the transfer tables installed in a large number of production lines, stockyards and the like. Since it is not necessary to provide a detection sensor and electrical wiring associated with these, the economic effect of cost reduction is great.

[Brief description of drawings]

FIG. 1 is a perspective view of an automated guided vehicle showing an embodiment of the present invention.

FIG. 2 is a schematic diagram of a control device.

FIG. 3 is a perspective view of a transfer table.

FIG. 4 is a side view of an automated guided vehicle and a transfer table.

FIG. 5 is a front view of an automated guided vehicle and a transfer table.

FIG. 6 is a schematic view showing a transfer state of an automatic guided vehicle.

FIG. 7 is a schematic view showing a transfer state of an automatic guided vehicle.

FIG. 8 is a schematic diagram showing a transfer state of an automated guided vehicle.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Automated guided vehicle, 2 ... Car body, 3 ... Running wheel device, 4 ... Running sensor, 5 ... Derivative, 6 ... Transfer stand, 7 ... Steel plate coil,
8 ... Lifter device, 8a ... Receiving platform of the lifter device 8, 8b,
8c ... Cylinder of the lifter device 8, 9 ... Mounting table, 10 ... Recess between the mounting tables 9 and 11, 11 ... Central control system, 12 ...
Coil detection sensor, 13 ... Control device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuro Morita 1-1, Sanbonmatsucho, Atsuta-ku, Nagoya, Aichi Japan Vehicle Manufacturing Co., Ltd.

Claims (4)

[Claims] 1. A longitudinal direction of a central portion of a vehicle body for supporting and lifting a cylindrical conveyed object placed on a transfer table formed in a gate shape in an axial direction of the cylindrical conveyed object. A lifter device that can be moved up and down, a pair of mounting tables that are spaced apart from each other on the right and left sides of the lifter device, and detects the axial length of the cylindrical conveyed object when entering the lower part of the transfer table. Sensor to
A control device for stopping the traveling of the vehicle body at a point where the axial center of the cylindrical object and the longitudinal center of the lifter device substantially match based on the data detected by the sensor; Characteristic automated guided vehicle. 2. A longitudinal center portion of a vehicle body for supporting and lifting a plurality of cylindrical articles carried on a transfer table formed in a gate shape in the axial direction of the articles. A lifter device that is vertically movable, a pair of mounting tables that are spaced apart from each other on the left and right of the lifter device, and an axial length of the cylindrical article when entering the lower part of the transfer table. A sensor for detecting the data, the data detected by the sensor, and the data such as the number of the cylindrical conveyed objects, the weight of the cylindrical conveyed objects, the type of the cylindrical conveyed objects and the arrangement order which are input in advance, and An automatic guided vehicle, comprising: a controller for stopping the traveling of the vehicle body at a point where the position of the total center of gravity of the cylindrical conveyed object and the longitudinal center of the lifter device substantially coincide with each other. 3. A longitudinal direction of a central portion of a vehicle body for supporting and lifting a plurality of cylindrical conveyed objects placed on a transfer table formed in a gate shape in an axial direction of the cylindrical conveyed objects. A lifter device that is vertically movable, a pair of mounting tables that are spaced apart from each other on the left and right of the lifter device, and an axial length of the cylindrical article when entering the lower part of the transfer table. A sensor for detecting the data, the data detected by the sensor, and the data such as the number of the cylindrical conveyed objects, the weight of the cylindrical conveyed objects, the type of the cylindrical conveyed objects and the arrangement order which are input in advance, and When the total center of gravity of the cylindrical conveyed product and the longitudinal center of the lifter device are substantially aligned with each other, when one end of the cylindrical conveyed product is located outside the end of the lifter device, An axial length center of the cylindrical conveyed object and a longitudinal center of the lifter device. An unmanned guided vehicle, comprising: a controller for stopping the traveling of the vehicle body at a point substantially coincident with. 4. When the control device detects that the cylindrical transferred object is placed on the transfer table in a state where the cylindrical transferred object is mounted on the mounting table. The automatic guided vehicle according to any one of claims 1 to 3, wherein entry to the lower part of the transfer table is stopped.