JP7759831B2 - Cargo handling vehicle, stowage control method, and stowage control program - Google Patents

Description

The present invention relates to a cargo handling vehicle, a stowage control method, and a stowage control program.

2. Description of the Related Art In recent years, unmanned (automatic) operation vehicles such as unmanned forklifts have become widespread as cargo handling vehicles for performing cargo handling operations.
The unmanned cargo handling vehicle described in Patent Document 1 uses a side shift mechanism that moves the forks in the vehicle width direction to fine-tune the loading position of the cargo after accessing (approaching) the loading destination.

Japanese Patent Application Laid-Open No. 2021-165897

However, with the technology described in Patent Document 1, there is a risk that the load on the fork may come into contact with loads already loaded when accessing the loading destination. Reliably avoiding such situations requires highly accurate positioning (position guidance).

The present invention was made in consideration of the above circumstances, and aims to ease the required accuracy for guiding the position of cargo handling vehicles.

The present invention provides
A drivable vehicle body,
a fork provided on the vehicle body and capable of holding a load;
a side shift device that can move the fork in the vehicle width direction;
a control means;
A cargo handling vehicle that sequentially loads a plurality of loads onto a loading section along a predetermined loading direction,
The control means
a first means for moving the forks holding the load downstream in the stowage direction by the side shift device;
a second means for moving the vehicle body toward the loading section while the forks are moved by the first means until the load on the forks is positioned on the loading section;
a third means for moving the forks holding the load to the upstream side in the stowage direction by the side shift device;
a fourth means for unloading the load onto the loading section;
Including,
the first means moves the forks using the side shift device while the vehicle body is facing the storage section,
The second means moves the vehicle body forward to approach the storage section .

The present invention also provides
A loading control method for a cargo handling vehicle including a travellable vehicle body, forks provided on the vehicle body and capable of holding loads, and a side shift device capable of moving the forks in a vehicle width direction, the method sequentially loading a plurality of loads onto a loading section along a predetermined loading direction,
The control means
a first step of moving the forks holding the load downstream in the stowage direction by the side shift device;
a second step of moving the vehicle body toward the loading section while keeping the forks moved in the first step until the load on the forks is positioned on the loading section;
a third step of moving the forks holding the load to the upstream side in the stowage direction by the side shift device;
a fourth step of unloading the load onto the placement portion;
Execute.

The present invention also provides
A loading control program for a cargo handling vehicle that includes a travellable vehicle body, forks that are provided on the vehicle body and can hold loads, and a side shift device that can move the forks in a vehicle width direction, and that sequentially loads a plurality of loads onto a loading section along a predetermined loading direction,
Computer,
a first means for moving the forks holding the load downstream in the stowage direction by the side shift device;
a second means for moving the vehicle body toward the loading section while keeping the forks moved by the first means until the load on the forks is positioned on the loading section;
a third means for moving the forks holding the load to the upstream side in the stowage direction by the side shift device;
a fourth means for unloading the load onto the loading section;
Function as.

This invention makes it possible to relax the required accuracy for guiding the position of cargo handling vehicles.

1 is a diagram showing a cargo handling system according to an embodiment; 1 is a block diagram showing a schematic control configuration of a cargo handling system according to an embodiment. 10 is a flowchart showing the flow of a stowage process according to the embodiment. FIG. 10 is a diagram for explaining a stowage process according to the embodiment. FIG. 10 is a diagram for explaining a stowage process according to the embodiment.

Embodiments of the present invention will be described in detail below with reference to the drawings.

[Loading system configuration]
FIG. 1 is a diagram showing a cargo handling system 1 according to this embodiment.
As shown in this figure, the cargo handling system 1 is a system that performs cargo handling work, for example, by sequentially loading multiple cargoes L from a warehouse onto the loading platform 41 of a truck 40 using an automated guided forklift (hereinafter referred to as "AGF") 20.
The AGF 20 travels along a predetermined guide route GR and sequentially loads multiple loads L onto the loading platform 41 along a loading direction X from the front to the rear of the truck 40. That is, the AGF 20 first accesses (approaches) the frontmost part of the loading platform 41 along the guide route GR1 and loads load L1, then picks up the next load L2, and then accesses a slightly rearward part of the loading platform 41 along the guide route GR2 and loads load L2 adjacent to load L1. By repeating this process, multiple loads L are sequentially loaded onto the loading platform 41 along the loading direction X.

FIG. 2 is a block diagram showing a schematic control configuration of the cargo handling system 1.
As shown in this figure, the cargo handling system 1 includes an AGF 20 and a control server 30 that controls the operation of the AGF 20 .

The AGF 20 is a cargo handling vehicle capable of transporting, lifting, and delivering cargo, and in this embodiment is an unmanned forklift that can travel on roads without using rails, etc. The AGF 20 is an example of a cargo handling vehicle according to the present invention, and is configured to be capable of automatic operation (unmanned operation) based on control commands from the control server 30.
Specifically, the AGF 20 includes a drive unit 21 , a cargo handling device 22 , a side shift device 23 , a communication unit 24 , a position measurement device 25 , a memory unit 26 , and a control unit 27 .

The drive unit 21 includes a travel motor and a steering motor (both not shown) which are various drive sources of the AGF 20. The travel motor drives the drive wheels among the wheels, and the steering motor rotates the steered wheels among the wheels (performs a steering operation).
The cargo handling device 22 is used to perform cargo handling operations excluding side shifting, and is provided at the front of the vehicle body of the AGF 20. The cargo handling device 22 includes a mast that can be tilted forward and backward in the vehicle body 20a, a pair of left and right forks 20b (see FIG. 1) that are attached to the mast so that they can be raised and lowered and that hold a load L, and a cargo handling motor that performs various operations such as raising and lowering the forks 20b and tilting them.

The side shift device 23 slides the pair of forks 20b in the vehicle width direction (left and right direction) relative to the vehicle body 20a. In other words, the AGF 20 is capable of moving the center C2 of the forks 20b (hereinafter referred to as the "fork center") left and right in the vehicle width direction using the side shift device 23 relative to the center C1 of the vehicle body 20a (hereinafter referred to as the "vehicle body center") (see Figure 4).

The communication unit 24 is a communication device capable of sending and receiving various types of information to and from the control server 30 .
The position measurement device 25 measures the position of the AGF 20 itself. Information about the self-position acquired by the position measurement device 25 is transmitted to, for example, the control server 30 and used for controlling the position of the AGF 20 itself. The specific configuration of the position measurement device 25 is not particularly limited, and for example, the position measurement device 25 may use a GNSS (Global Navigation Satellite System). Alternatively, the position measurement device 25 may use a sensor (such as an inertial measurement unit) that measures the traveling direction and a traveling distance sensor to sequentially integrate the traveling direction and distance over a very short period of time to measure the position, or may measure the position of the AGF 20 by detecting reflectors (markers) placed at various locations in the work area with an optical sensor and comparing the detected reflectors with preset reflector placement information.

The storage unit 26 is a memory configured, for example, by RAM (Random Access Memory) or ROM (Read Only Memory), and stores various programs and data, and also functions as a work area for the control unit 27. In this embodiment, the storage unit 26 pre-stores a stowage program 260 for executing a stowage process (see FIG. 3 ), which will be described later, and map information 261 of the work area, which includes information on the positions of required objects and information on the guide route GR.
The control unit 27 is configured by, for example, a CPU (Central Processing Unit) and controls the operation of each unit of the AGF 20. Specifically, the control unit 27 operates each unit based on operation commands from the control server 30, deploys programs stored in advance in the storage unit 26, and executes various processes in cooperation with the deployed programs.

The control server 30 centrally controls the cargo handling system 1 and is configured to be able to control the operation of at least one AGF 20. The control server 30 may be any server that can control the cargo handling system 1, and may be configured, for example, by a terminal device and a cloud server.
Specifically, the control server 30 includes an operation unit 31 , a display unit 32 , a communication unit 35 , a storage unit 36 , and a control unit 37 .

The operation unit 31 is an operation means through which an operator performs various operations to operate the control server 30, and includes, for example, pointing devices such as a mouse and a keyboard.
The display unit 32 is, for example, a liquid crystal display, an organic electroluminescence display, or another display, and displays various information based on a display signal input from the control unit 37. The display unit 32 may be a touch panel that also serves as at least a part of the operation unit 31. The display unit 32 may also include an audio output unit that is capable of outputting audio.

The communication unit 35 is a communication device capable of transmitting and receiving various types of information to and from the AGF 20 .
The storage unit 36 is a memory configured by, for example, a RAM (Random Access Memory) or a ROM (Read Only Memory), and stores various programs and data, and also functions as a work area for the control unit 37 .
The control unit 37 is configured by, for example, a CPU (Central Processing Unit) and controls the operation of each unit of the control server 30. Specifically, the control unit 37 deploys a program stored in advance in the storage unit 36 based on the operation content of the operation unit 31, and executes various processes in cooperation with the deployed program.

[Load handling system operation]
Next, the operation of the cargo handling system 1 when executing a stowage process in which the AGF 20 sequentially stacks a plurality of cargoes L onto the loading platform 41 of the truck 40 will be described.
FIG. 3 is a flowchart showing the flow of this stowage processing, and FIGS. 4 and 5 are diagrams for explaining the stowage processing.
The stowage process is a process executed when the AGF 20 sequentially stows a plurality of loads L onto the loading platform 41 of the truck 40. This stowage process is executed by the control unit 27 of the AGF 20 reading and developing the stowage program 260 from the memory unit 26 based on, for example, a work start command from the control server 30.
In the following, the direction along the front-to-back direction of the AGF 20 facing the loading platform 41 of the truck 40 will be referred to as the "depth direction," and the side of this depth direction closer to the AGF 20 will be referred to as the "front side" and the side farther away will be referred to as the "back side."

As shown in FIG. 3, when the stowage process is executed, the control unit 27 first picks up the cargo L stored in, for example, a warehouse (step S1).
At this time, the AGF 20 retrieves the load while keeping the fork center C2 aligned with the vehicle body center C1 (normal state).

Next, the control unit 27 causes the AGF 20 to travel (move) along the guide route GR and stops the AGF 20 with the vehicle body 20a facing directly to the side of the loading platform 41 of the truck 40 (step S2; FIG. 4A). "Facing the vehicle body 20a directly to the side of the loading platform 41" means that the front of the vehicle body 20a is facing the loading platform 41 at the side of the truck 40 (however, it is sufficient that the vehicle body 20a faces the loading platform 41 within a predetermined angle range).
At this time, the AGF 20 still maintains a state in which the fork center C2 coincides with the vehicle body center C1.
In this embodiment, the loaded cargo L0 is placed on the loading platform 41 at an adjacent position upstream (to the right of the figure) in the loading direction X of the planned loading position P where the cargo L held at this time will be loaded.

Next, the control unit 27 drives the side shift device 23 to slide (move) the fork 20b holding the load L downstream in the stowage direction X (to the left in the drawing) (step S3; FIG. 4(b)).
Here, the fork 20b is slid, for example, by the maximum slide amount (side shift amount) in the vehicle width direction until the fork center C2 is positioned downstream in the loading direction X from the vehicle body center C1.

Next, the control unit 27 moves the AGF 20 forward to a predetermined loading position (depth position) while maintaining the side shift state of step S3 in which the forks 20b have been moved downstream in the loading direction X, to access (approach) the loading platform 41 (step S4; FIG. 5(a)). The predetermined loading position (depth position) is the depth position of the AGF 20 that corresponds to the depth position of the planned loading position P of the load L. However, it is sufficient that the load L on the forks 20b is located at a depth position on the loading platform 41.
As a result, the load L is transported to the depth position corresponding to the loaded load L0.

At this time, the AGF 20 has already moved the forks 20b downstream in the loading direction X to a position on the loading platform 41 where no load L has yet been loaded, thereby reducing the risk of contact (interference) between the load L on the forks 20b and the loaded load L0.

Next, the control unit 27 drives the side shift device 23 to slide (move) the fork 20b holding the load L upstream in the stowage direction X (to the right in the drawing) (step S5; FIG. 5(b)).
Here, the fork 20b is slid in the vehicle width direction until the fork center C2 is positioned upstream of the vehicle body center C1 in the loading direction X.
The forks 20b may continue to slide until the load L on the forks 20b and the loaded load L0 are at a predetermined distance or until they come into contact. When the load L on the forks 20b and the loaded load L0 are brought into contact with each other, the contact can be detected by detecting the pressure of the actuator of the side shift device 23, for example, and the sliding of the forks 20b can be stopped when the contact is detected.

Next, the control unit 27 drives the cargo handling device 22 to lift down the cargo L and place it on the loading platform 41 (step S6).

Next, the control unit 27 determines whether or not to terminate the stowage process (step S7), and if it determines not to terminate it (step S7; No), it transitions to the processing of step S1 described above and continues the loading and unloading operation.
Then, if it is determined that the stowage process should be terminated, for example, because all cargo L has been loaded (step S7; Yes), the control unit 27 moves the AGF 20 to a predetermined waiting position and then terminates the stowage process.

[Technical effect of this embodiment]
As described above, according to this embodiment, while the forks 20b holding the cargo L are moved downstream in the stowage direction X, the vehicle body 20a is moved closer to the loading platform 41 until the cargo L on the forks 20b is positioned on the loading platform 41, and then the forks 20b holding the cargo L are moved upstream in the stowage direction X.
In other words, the AGF 20 moves the forks 20b in advance to the upstream side in the loading direction X where the load L has not yet been loaded on the loading platform 41, thereby reducing the risk of contact (interference) between the load L on the forks 20b and the loaded load L0 when accessing the loading platform 41. Consequently, the required accuracy for guiding the position of the AGF 20 can be relaxed.

In other words, if the position guidance accuracy is worse than the sum of the required clearance between the loads L, the positional deviation of the loaded load L0, and the positional deviation when the load L is picked up during transportation, even if the fork 20b is slid upstream in the loading direction X after accessing the loading platform 41, the load L cannot be slid to a position adjacent to the load L0.
For example, the required clearance A between the loads L is 20 mm, the positional deviation B of the loaded load L0 is 15 mm, the positional deviation D of the load L during transportation is 15 mm, and the maximum side shift amount E is 150 mm on both sides. In this case, the required position guidance accuracy G of the AGF 20 is as follows when the fork 20b is slid upstream in the loading direction X after accessing the loading platform 41:
G < E/2 - (A+B+D)
< 150/2 - (20 + 15 + 15)
< 25
This becomes:
In contrast, as in this embodiment, when the forks 20b are slid to the downstream side in the stowage direction X in advance to access the loading platform 41, and then the forks 20b are slid to the upstream side in the stowage direction X, the required position guidance accuracy G of the AGF 20 is as follows:
G < E - (A+B+D)
< 150 - (20 + 15 + 15)
< 100
In other words, according to this embodiment, the required accuracy of position guidance can be relaxed from 25 mm to 100 mm.

[others]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments.
For example, in the stowage process of the above embodiment, in step S3, the forks 20b are slid downstream in the stowage direction X while facing the loading platform 41. However, it is sufficient if the forks 20b are slid downstream in the stowage direction X in advance before accessing the loading platform 41 (step S4). For example, the forks 20b may be slid before facing the loading platform 41 in step S2. However, in this case, there is a risk that the speed may be limited due to deterioration in the balance of the vehicle body 20a while traveling, or that the overall vehicle width may increase by the amount of sliding of the forks 20b, thereby increasing the required aisle width.
Furthermore, the AGF 20 does not need to stop in steps S2 and S3 if the forks 20b are previously slid downstream in the stowage direction X before step S4. For example, the forks 20b may be slid while moving forward toward the loading platform 41.

Also, for example, if the cargo handling vehicle is capable of moving in the width direction, the cargo may be slid by traveling in the loading direction instead of using the side shift function. However, in this case, there is a risk that guidance accuracy errors may be superimposed even when the vehicle slides in the loading direction.

Furthermore, in the above embodiment, an example was described in which cargo L is loaded onto the bed 41 of a truck 40. However, the loading section according to the present invention is not limited to the bed of a truck, and may be, for example, a shelf (board) or the like, as long as it allows multiple cargoes to be stacked sequentially in a predetermined stacking direction.

In addition, in the above embodiment, the AGF 20 operates independently of the control server 30 (except at the start of work), but the control server 30 may also control the operation of the AGF 20, including position guidance. In this case, the map information 261 is stored in the memory unit 36 of the control server 30, and the control unit 37 of the control server 30 may guide the AGF 20 by referring to the map information 261. The self-position of the AGF 20 may be determined by the position measurement device 25 of the AGF 20 and received by the control server 30, for example.

In the above embodiment, an AGF was used as an example of a cargo handling vehicle. However, the cargo handling vehicle according to the present invention is not limited to unmanned vehicles that operate unmanned, but also includes vehicles that can be operated manned (including remotely) and vehicles that can switch between manned and unmanned operation. The present invention can also be used as an assist function for manned operation.
Furthermore, the cargo handling vehicle according to the present invention is not limited to a forklift, as long as it can move while holding a load with forks (or the like), and includes, for example, an automated guided vehicle (AGV) that moves without a driver.
In addition, the details shown in the above embodiment can be modified as appropriate without departing from the spirit of the invention.

1. Cargo handling system 20 AGF (unmanned forklift, cargo handling vehicle)
20a Vehicle body 20b Fork 23 Side shift device 27 Control unit (control means)
40 Truck 41 Loading platform (loading area)
260 Stowage program (stowage control program)
261 Map information C1 Vehicle center (center of vehicle body)
C2 Fork center (fork center)
GR Guidance route L Load L0 Load (loaded load)
P Planned loading position X Loading direction

Claims (6)

A drivable vehicle body,
a fork provided on the vehicle body and capable of holding a load;
a side shift device that can move the fork in the vehicle width direction;
a control means;
A cargo handling vehicle that sequentially loads a plurality of loads onto a loading section along a predetermined loading direction,
The control means
a first means for moving the forks holding the load downstream in the stowage direction by the side shift device;
a second means for moving the vehicle body toward the loading section while the forks are moved by the first means until the load on the forks is positioned on the loading section;
a third means for moving the forks holding the load to the upstream side in the stowage direction by the side shift device;
a fourth means for unloading the load onto the loading section;
Including,
the first means moves the forks using the side shift device while the vehicle body is facing the storage section,
The second means moves the vehicle body forward to approach the storage section.
Loading vehicle. The first means moves the center of the fork downstream in the loading direction from the center of the vehicle body in the vehicle width direction.
The cargo handling vehicle according to claim 1 . The third means moves the center of the fork in the vehicle width direction to the upstream side in the stacking direction relative to the center of the vehicle body.
3. The cargo handling vehicle according to claim 1 or 2 . The cargo handling vehicle is an unmanned vehicle that operates without a driver.
The cargo handling vehicle according to any one of claims 1 to 3 . A loading control method for a cargo handling vehicle including a travellable vehicle body, forks provided on the vehicle body and capable of holding loads, and a side shift device capable of moving the forks in a vehicle width direction, the method sequentially loading a plurality of loads onto a loading section along a predetermined loading direction,
The control means
a first step of moving the forks holding the load downstream in the stowage direction by the side shift device;
a second step of moving the vehicle body toward the loading section while keeping the forks moved in the first step until the load on the forks is positioned on the loading section;
a third step of moving the forks holding the load to the upstream side in the stowage direction by the side shift device;
a fourth step of unloading the load onto the placement portion;
A stowage control method that performs the above. A loading control program for a cargo handling vehicle that includes a travellable vehicle body, forks that are provided on the vehicle body and can hold loads, and a side shift device that can move the forks in a vehicle width direction, and that sequentially loads a plurality of loads onto a loading section along a predetermined loading direction,
Computer,
a first means for moving the forks holding the load downstream in the stowage direction by the side shift device;
a second means for moving the vehicle body toward the loading section while keeping the forks moved by the first means until the load on the forks is positioned on the loading section;
a third means for moving the forks holding the load to the upstream side in the stowage direction by the side shift device;
a fourth means for unloading the load onto the loading section;
A stowage control program that functions as a