JP2024094461A - Cargo handling vehicle, control method for cargo handling vehicle, and control program for cargo handling vehicle - Google Patents

Abstract

To improve safety of cargo handling operation.SOLUTION: A fork lift 1 includes: a vehicle body 10 which can travel in a travel direction in a predetermined orientation; a fork 12 which is provided at a side different from the front side in a travel direction of the vehicle body 10 to hold cargo; a 3D distance sensor 24 which is provided facing forward in the travel direction at the vehicle body 10 and acquires distance information; and a control unit 27 which determines whether or not an obstacle exists based on the distance information acquired by the 3D distance sensor 24. The structure enables improvement of safety of cargo handling operation.SELECTED DRAWING: Figure 3

Description

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

At construction sites where loading and unloading vehicles such as forklifts are used, there is a risk of collision between the loading and unloading vehicle and workers (people) or objects.
In view of this, for example, the technology described in Patent Document 1 determines the presence or absence of an object around the vehicle body based on an image captured by an on-board camera.

JP 2021-33403 A

However, in the technology described in Patent Document 1, since a load is loaded onto the forks at the front of the vehicle body (the front side in the direction of travel), there is a risk that the load will block the field of view of the onboard camera (shooting range).
The present invention has been made in consideration of the above circumstances, and has an object to improve the safety of loading and unloading operations.

The loading vehicle according to the present invention comprises:
A vehicle body capable of traveling in a predetermined direction;
A loading device is provided on a side of the vehicle body other than the front side in the traveling direction and holds a load;
a three-dimensional distance measuring unit provided on the vehicle body facing forward in the traveling direction and configured to acquire distance information;
a determination means for determining the presence or absence of an obstacle based on the distance information acquired by the distance measuring unit;
Equipped with.

The present invention can improve the safety of loading and unloading operations.

FIG. 1 is a side view of a forklift according to an embodiment. 1 is a block diagram showing a schematic control configuration of a forklift according to an embodiment of the present invention; 5 is a flowchart showing a flow of an obstacle detection process according to the embodiment. 10A and 10B are diagrams for explaining an obstacle detection process according to the embodiment; 11A and 11B are diagrams for explaining a modified example of the configuration of the distance sensor according to the embodiment.

The following describes an embodiment of the present invention in detail with reference to the drawings.

[Forklift configuration]
FIG. 1 is a side view of a forklift 1 according to the present embodiment.
The forklift 1 according to the present embodiment is an example of a cargo handling vehicle according to the present invention, and performs cargo handling work including, for example, transporting cargo L in a warehouse. The forklift 1 is, but is not limited to, an automated guided forklift (AGF) that can operate unmanned (automatically), and performs a predetermined cargo handling work based on operation commands from a management server (not shown).

Specifically, the vehicle body 10 of the forklift 1 includes a vehicle body 11, forks 12, a lifting body (lift) 13, a mast 14, and wheels 15. The vehicle body 10 is capable of traveling in a predetermined direction in the direction of travel. The mast 14 is provided at the rear of the vehicle body 11, and is driven by a driving source (not shown) to tilt the vehicle body 11 forward and backward. The lifting body 13 is driven by a driving source (not shown) to rise and fall along the mast 14. A pair of left and right forks 12 for holding a load L, a pallet 30, etc. are attached to the lifting body 13. The pair of forks 12 can be tilted and raised and lowered relative to the vehicle body 11 by driving the mast 14 and the lifting body 13. The loading device according to the present invention includes a pair of forks 12, the lifting body 13, and the mast 14. Note that the mast 14 may not be tilted, and the lifting body 13 may be tilted relative to the mast 14.
The pair of forks 12, the lifting body 13, and the mast 14 are provided facing backward on the rear side of the vehicle body 10, opposite the front side in the traveling direction of the forklift 1. In the following, unless otherwise specified, the descriptions of the front, rear, left and right directions refer to the directions corresponding to the traveling direction of the forklift 1 (the directions shown in Figure 1).
The pallet 30 is a load-receiving platform on which the load L is placed. The pallet 30 is formed in a short rectangular plate shape and has two holes (fork pockets) 32 into which the pair of forks 12 are inserted.

FIG. 2 is a block diagram showing a schematic control configuration of the forklift 1.
As shown in this figure, in addition to the above-mentioned components, the forklift 1 is equipped with a drive unit 21, an operation unit 22, a display unit 23, a communication unit 28, two 3D distance sensors 24, a position measurement device 25, a memory unit 26, and a control unit 27.

The drive unit 21 includes a travel motor, a steering motor, and a loading motor (all not shown), which are various drive sources of the forklift 1. The travel motor drives the drive wheels of the wheels 15. The steering motor rotates (steers) the steering wheels of the wheels 15. The loading motor is a drive source that performs the actions of raising and lowering the lifting body 13 and tilting the mast 14.

The operation unit 22 is an operation means by which a driver performs various operations during manned (manual) driving, for example. The operation unit 22 includes, for example, a steering wheel, pedals, levers, various buttons, etc., and outputs operation signals according to the contents of these operations to the control unit 27.
The display unit 23 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 27. The display unit 23 may be a touch panel that also serves as part of the operation unit 22. The display unit 23 may also include an audio output unit that is capable of outputting audio.
The communication unit 28 is a communication device capable of transmitting and receiving various types of information to and from a management server and the like.

The two 3D distance sensors 24 are examples of distance measuring units according to the present invention, and each acquires distance information within a predetermined scan area (measurement area) N and outputs the result to the control unit 27. The 3D distance sensor 24 of this embodiment is, for example, a three-dimensional distance sensor (for example, a three-dimensional LiDAR (LASER Imaging Detection and Ranging)) having a three-dimensional scan area N (see FIG. 1 ).
The two 3D distance sensors 24 include a 3D distance sensor 24F provided facing forward in the front portion of the vehicle body 10, and a 3D distance sensor 24B provided facing backward in the rear portion of the head guard. The two 3D distance sensors 24 are disposed diagonally on the vehicle body 10 (head guard) in a plan view, with scan areas N facing in opposite directions, and each having a scan range of 270°. Therefore, the entire circumference of 360° is included in the sensing range in a plan view as seen from the forklift 1.
Each 3D distance sensor 24 is disposed in an upper portion of the vehicle body 10, and in this embodiment, is disposed on the top surface (upper surface) of the head guard (see FIG. 1). Each 3D distance sensor 24 is disposed so that the scan area N has a positive elevation angle (upward angle) and can measure an area above the vehicle body 10.

The position measuring device 25 measures the position of the forklift 1 itself. The information on the self-position acquired by the position measuring device 25 is transmitted to, for example, a management server and used to confirm (monitor) the position of the forklift 1 itself. The specific configuration of the position measuring device 25 is not particularly limited, and may be, for example, one that uses a GNSS (Global Navigation Satellite System). Alternatively, the position measuring device 25 may be one that uses a sensor (such as an inertial measurement unit) that measures the traveling direction and a traveling distance sensor to sequentially integrate the direction and distance traveled over a very short period of time to measure the position, or one that uses an optical sensor to detect reflectors (markers) placed at various locations in the work area and compares them with preset reflector placement information to measure the position of the forklift 1.

The storage unit 26 is a memory configured, for example, by 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 27. The storage unit 26 in this embodiment pre-stores an obstacle detection program 260 for executing an obstacle detection process (see FIG. 3 ) described below.
The control unit 27 is configured with, for example, a CPU (Central Processing Unit) and controls the operation of each part of the forklift 1. Specifically, the control unit 27 operates the drive unit 21 based on an operation command from the management server, deploys a program pre-stored in the storage unit 26, and executes various processes in cooperation with the deployed program.

[Obstacle detection processing]
Next, an operation of the forklift 1 performing obstacle detection processing during loading and unloading operations will be described.
Fig. 3 is a flowchart showing the flow of the obstacle detection process Fig. 4 is a diagram for explaining the obstacle detection process.

The obstacle detection process is a process for detecting surrounding obstacles when the forklift 1 is performing a loading/unloading operation, and is a process that is continuously executed during traveling. The obstacle detection process is executed by the control unit 27 of the forklift 1 reading out the obstacle detection program 260 from the storage unit 26 and developing it.
To briefly outline the flow, detection processing is performed at a predetermined control cycle (step S2), and if an obstacle is detected, travel is stopped (step S5), and when the obstacle is no longer detected, work is resumed (step S8), and if the obstacle remains detected for a predetermined period of time, an alarm is sounded (step S7).
The obstacle detection process may be included in the loading and unloading process that controls almost the entire loading and unloading operation.

As shown in FIG. 3, when the obstacle detection process is executed in conjunction with the loading and unloading process, the control unit 27 first starts the loading and unloading operation of transporting the load L on the pallet 30, for example, in a warehouse, based on an operation command from a management server (not shown) (step S1).

When loading and unloading work is started, the control unit 27 scans the surroundings using the two 3D distance sensors 24 (step S2).
Specifically, the control unit 27 scans the front side in the traveling direction with the front 3D distance sensor 24F and the rear side in the traveling direction with the rear 3D distance sensor 24B. Then, the control unit 27 obtains distance information in the scan area N of each 3D distance sensor 24 and detects an object in the scan area N.

Next, the control unit 27 generates map information having information on the presence or absence of an object based on the distance information acquired by the 3D distance sensor 24, and stores the map information in the storage unit 26 (step S3).
Here, 3D mapping of the work site (e.g., a warehouse) is performed, and the information is updated as needed. The angle range of the map information is, for example, 20 degrees upward (elevation angle) and 40 degrees downward (depression angle) for each 3D distance sensor 24, and it is desirable that the ceiling 2 to 3 meters ahead can be seen from the tip of the fork 12 at the front of the vehicle. The generated map information may be shared with a management server or other forklifts 1 through the communication unit 28. Furthermore, if map information that has already been generated exists (in the forklift itself or in the management server), the control unit 27 may compare the scan result of step S2 with the map information, and output a warning when the degree of match is equal to or less than a predetermined value.

Next, the control unit 27 determines whether or not an obstacle is present ahead of the vehicle body 10 (in the traveling direction) based on the scan result in step S2 (step S4).
Specifically, the control unit 27 judges whether there is an obstacle ahead based on distance information acquired by the front 3D distance sensor 24F. Here, the "obstacle" ahead refers to an object that may come into contact with the forklift 1 when traveling in the forward direction, including a person (worker, etc.). However, for example, an object smaller than a predetermined size may be set to be ignored as being no problem (determined not to exist). The control unit 27 judges the possibility of contact between the forklift 1 and an obstacle based on the height, width, etc. of the forklift 1 (vehicle body 10) and the load L being held.

In step S4, when it is determined that no obstacle is present in front of the vehicle body 10 (step S4; No), the control unit 27 continues the loading/unloading operation (step S8) and transitions to step S9 described below.
For example, as shown in Fig. 4(a), if the shutter SH located in front is raised above the maximum height of the forklift 1 (including the load L held by the forklift 1), there is no risk of contact with the shutter SH even if the forklift 1 continues moving forward, so the control unit 27 determines that there is no obstacle ahead and continues working. The heights of the forklift 1 (body 10) and the load L are obtained in advance from the management server. By making it possible to obtain information on the size and shape of the load L and the forklift 1 from the management server, it is possible to obtain more accurately information on the distance and position of the detection target and to appropriately determine contact with the detection target.

On the other hand, when it is determined in step S4 that an obstacle is present in front of the vehicle body 10 (step S4; Yes), the control unit 27 stops the traveling of the forklift 1 (step S5).
For example, as shown in FIG. 4( b ), if the front shutter SH is not fully raised and its bottom end does not exceed the height of the forklift 1, there is a risk of contact with the shutter SH if the forklift 1 continues to move forward, so the control unit 27 recognizes the shutter SH as an obstacle and stops the forklift 1 from traveling.

Next, the control unit 27 determines whether or not a predetermined time has elapsed since the stopping of traveling in step S5 (or the determination in step S4 immediately before that) (step S6).
Here, the "predetermined time" is the time when it is estimated that the situation of the obstacle ahead will change, for example, the time it takes for the shutter SH in the warehouse to be completely raised (approximately 30 seconds). In other words, if the obstacle is automatically or manually moved, the vehicle can resume traveling, but if the obstacle remains after a long time (i.e., even after the predetermined time has passed), it is desirable to notify the system, the manager, or surrounding workers of the situation. This "predetermined time" can be considered as a set time for the system or a person to decide that intervention is necessary in cases such as when the loading vehicle is lifted too high or the load is too large to fit the upper height limit of the warehouse (a time to observe the situation for a while, since the problem may be resolved automatically).

In step S6, when it is determined that the predetermined time has not elapsed since step S5 (or the immediately preceding step S4) (step S6; No), the control unit 27 shifts the process to the above-mentioned step S2.
Therefore, the scanning in step S2 and the determination of the presence or absence of an obstacle in step S4 are continuously repeated until the obstacle is removed or a predetermined time has elapsed.
In addition, if it is confirmed that the obstacle has been removed before the specified time has elapsed (Step S6; No followed by Step S4; No), or if the worker manually resumes the work, the work may be resumed even before the specified time has elapsed.

On the other hand, in step S6, if it is determined that a predetermined time has elapsed since step S5 (or the immediately preceding step S4) (step S6; Yes), the control unit 27 outputs a warning to warn (notify) the user that an obstacle is present on the driving route (step S7), and terminates the obstacle detection process.
Here, the control unit 27 notifies nearby workers and the management server of the presence of an obstacle on the travel route by displaying a warning display or outputting a warning sound on the display unit 23, and waits for the worker (human) to respond. In this case, the output (notification) mode is not particularly limited, and a notification signal may be sent to the management server. If the presence of the obstacle is not resolved no matter how long it takes (even after a predetermined time has passed), a warning (notification) is issued to the surroundings or the system, so that other workers, supervisors, and the system can be prompted to improve the situation.

Next, the control unit 27 determines whether or not to terminate the obstacle detection process (step S9), and if it determines not to terminate it (step S9; No), it transitions to the processing of the above-mentioned step S2 and continues the loading and unloading operation.
Then, when it is determined that the obstacle detection process should be ended, for example, due to the end of loading and unloading work (step S9; Yes), the control unit 27 ends the obstacle detection process.

[Technical effect of the present embodiment]
As described above, according to this embodiment, the fork 12 is provided on the rear side of the vehicle body 10 in the direction of travel, and the presence or absence of an obstacle is determined based on distance information acquired by the 3D distance sensor 24 provided on the vehicle body 10 facing forward (forward in the direction of travel).
This allows the 3D distance sensor 24 to preferably detect an object ahead without the load L blocking the field of view, thereby improving the safety of loading and unloading operations.

Further, according to this embodiment, the 3D distance sensor 24 is disposed so as to be able to measure the area above the vehicle body 10 .
This makes it possible to effectively detect obstacles such as shutters SH that may come into contact with the upper part of the forklift 1.

Furthermore, according to this embodiment, information on the presence or absence of an object is stored based on the distance information acquired by the 3D distance sensor 24 .
This allows information on the presence or absence of the object to be converted into map information, which can be used for controlling the forklift 1, etc.

According to this embodiment, when it is determined that an obstacle is present ahead of the forklift 1 (on the forward side in the traveling direction), the traveling of the vehicle body 10 is stopped. If an obstacle is still present ahead in the traveling direction after a predetermined time has elapsed, the presence of an obstacle is notified. If the obstacle is no longer present ahead in the traveling direction within the predetermined time, the traveling of the vehicle body 10 is resumed.
As a result, when an obstacle only temporarily blocks the travel path of the forklift 1, the forklift 1 can quickly resume work without bothering an operator (maintenance personnel), and the forklift 1, which is an unmanned vehicle, can be operated smoothly.

[others]
Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment (including the modified examples).
For example, in the above embodiment, two 3D distance sensors 24 are provided at the front and rear portions of the vehicle body 10. However, as long as at least a forward-facing 3D distance sensor 24 is provided, the positions and the number of the sensors are not particularly limited. For example, only one 3D distance sensor may be used to sense 360° around the forklift 1. The type of the 3D distance sensor 24 is not particularly limited, and may be an optical sensor, an image sensor, or the like.

Furthermore, in the above embodiment, the 3D distance sensor 24 is used, but instead of a three-dimensional distance sensor, a two-dimensional distance sensor having a planar scan area may be used.
In this case, for example, as shown in Fig. 5, distance sensors 24a may be provided at multiple levels (two levels in Fig. 5) with different heights. The height at which the distance sensors 24a are arranged may include, for example, the lower part of the vehicle body 10 and the topmost part of the vehicle body 10. Each distance sensor 24a is installed so that the planar scan area Na is perpendicular to the up-down direction of the vehicle body 10. It is preferable that the distance sensors 24a at each level (height) are provided as a pair of two sensors that detect different directions. In this case, it is preferable that the scan areas Na of the pair of distance sensors 24a face in opposite directions in a plan view, each sensor has an angle range of 270°, and the entire circumference of 360° is included in the sensing range.

In addition, in the obstacle detection process of the above embodiment, the warning output of step S7 is performed after a predetermined time has elapsed since the vehicle stopped traveling in step S5. However, the warning output of step S7 may be performed after the vehicle stopped traveling in step S5 without waiting for the predetermined time to elapse. In addition, by issuing different types of notifications so that those around can understand when the vehicle is temporarily stopped and when rescue is required, the surroundings and the system can quickly recognize the response that should be taken.

In the above embodiment, the loading device including the forks 12 is provided on the rear side of the vehicle body 10. However, the loading device may be provided on a side of the vehicle body 10 other than the front side in the traveling direction.
In addition, although it has been stated that the vehicle body 10 can travel in a predetermined direction in the forward direction, this means that the vehicle body 10 is always in a predetermined direction when moving forward, and does not mean that it cannot be steered left or right or reverse.

In the above embodiment, the control unit 27 mounted on the forklift 1 performs various calculations, etc. However, a control means (e.g., a management server) provided outside the forklift 1 may perform calculations based on information transmitted from the forklift 1 and transmit the results to the forklift 1.

In the above embodiment, the forklift 1 is an unmanned transport forklift. However, the cargo handling vehicle according to the present invention includes a vehicle capable of being operated by a person (including remote control) and a vehicle capable of switching between being operated by a person and being unmanned. The present invention can also be used as an assist function for the operation of a person.
In addition, the loading vehicle according to the present invention is not limited to a forklift as long as it can carry a load using forks (or a similar loading device) and can travel while holding a load, and can also include, for example, an automated guided vehicle (AGV) that travels 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. Forklift (cargo handling vehicle)
10 Vehicle body 12 Fork (loading device)
13 Lifting body 14 Mast 23 Display unit (notification unit)
24, 24B, 24F 3D distance sensor (distance measuring section)
24a Distance sensor 26 Memory unit (information storage unit)
27 Control unit (determination unit, vehicle body control unit)
260 Obstacle detection program L Load N Scan area SH Shutter

Claims (8)

A vehicle body capable of traveling in a predetermined direction;
A loading device is provided on a side of the vehicle body other than the front side in the traveling direction and holds a load;
a three-dimensional distance measuring unit provided on the vehicle body facing forward in the traveling direction and configured to acquire distance information;
a determination unit that determines the presence or absence of an obstacle based on the distance information acquired by the distance measurement unit;
A loading vehicle equipped with: The distance measuring unit is arranged so as to be able to measure an area above the vehicle body.
The loading vehicle according to claim 1. an information storage unit that stores information on the presence or absence of an object at a predetermined height based on the distance information acquired by the distance measuring unit;
The loading vehicle according to claim 1. a vehicle body control unit that stops the vehicle body from traveling when the determination unit determines that an obstacle is present ahead in the traveling direction;
The loading vehicle according to claim 1. a notification unit that notifies the driver of the presence of an obstacle when an obstacle is present ahead in the traveling direction even after a predetermined time has elapsed since the vehicle body was stopped;
5. The loading vehicle according to claim 4. the vehicle body control unit resumes traveling of the vehicle body when an obstacle is no longer present ahead of the vehicle body in a traveling direction within a predetermined time period after the vehicle body has stopped.
5. The loading vehicle according to claim 4. A method for controlling a cargo handling vehicle including a vehicle body capable of traveling in a predetermined direction, a cargo handling device provided on the vehicle body for holding a cargo, and a distance measuring unit provided on the vehicle body for acquiring distance information, comprising:
The loading device is provided on a side of the vehicle body other than the front side in the traveling direction,
The distance measuring unit is provided on the vehicle body facing forward in the traveling direction,
The control unit executes a determination step of determining whether or not an obstacle is present based on the distance information acquired by the distance measuring unit.
A method for controlling a loading vehicle. A method for controlling a cargo handling vehicle including a vehicle body capable of traveling in a predetermined direction, a cargo handling device provided on the vehicle body for holding a cargo, and a distance measuring unit provided on the vehicle body for acquiring distance information, comprising:
The loading device is provided on a side of the vehicle body other than the front side in the traveling direction,
The distance measuring unit is provided on the vehicle body facing forward in the traveling direction,
causing the computer to function as a determination unit that determines the presence or absence of an obstacle based on the distance information acquired by the distance measuring unit;
A control program for loading and unloading vehicles.

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