JP7817871B2 - Loading vehicles and programs - Google Patents

Description

The present invention relates to a cargo handling vehicle and a program.

2. Description of the Related Art Cargo handling operations using cargo handling vehicles such as forklifts may involve loading and unloading cargo onto the bed of a truck or the like (see, for example, Patent Document 1).
In this type of cargo handling work, for example, when loading cargo onto a loading platform, if there is an obstacle such as another cargo in the planned loading position, there is a risk of damaging the cargo or the vehicle body and reducing work efficiency. Therefore, it is desirable to be able to conveniently check whether there are any obstacles on the loading platform before loading the cargo.

Japanese Patent Application Laid-Open No. 2020-83520

The present invention was developed in consideration of the above circumstances, and aims to improve the work efficiency of loading and unloading operations.

The cargo handling vehicle according to the present invention comprises:
A drivable vehicle body,
a measuring means provided on the vehicle body and capable of acquiring distance information;
a control means;
Equipped with
The control means operates the measuring means while turning the vehicle body so as to face a loading section on which a load is placed, and acquires distance information within a predetermined range above the loading section.

The program according to the present invention comprises:
A drivable vehicle body,
a measuring means provided on the vehicle body and capable of acquiring distance information;
A computer of a loading vehicle comprising:
a control means for operating the measuring means while rotating the vehicle body so as to face a loading section on which a load is to be placed, and acquiring distance information within a predetermined range above the loading section;
Function as.

This invention can improve the efficiency of loading and unloading operations.

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. FIG. 10 is a flowchart showing the flow of a loading process according to the embodiment. FIG. 10 is a diagram for explaining a loading process according to the embodiment. FIG. 10 is a diagram for explaining a loading process according to the embodiment. FIG. 10 is a diagram for explaining a loading process according to the embodiment. FIG. 10 is a diagram for explaining a loading process according to the embodiment. FIG. 10 is a diagram for explaining a loading process according to the embodiment. FIG. 10 is a plan view showing another example of a turning operation when the forklift truck according to the embodiment faces the loading platform.

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

[Forklift configuration]
FIG. 1 is a side view of a forklift truck 1 according to this embodiment.
The forklift 1 according to this embodiment is an example of a cargo handling vehicle according to the present invention, and performs cargo handling operations including loading cargo L onto a loading platform 41 (see FIG. 4 ) of a truck 40. The forklift 1 is, but is not limited to, an automated guided forklift (AGF) that can operate unmanned (automatically), and performs predetermined cargo handling operations 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 lift (lift) 13, a mast 14, and wheels 15. The mast 14 is provided at the front of the vehicle body 11 and is driven by a drive source (not shown) to tilt the vehicle body 11 forward and backward. The lift 13 is driven by a drive source (not shown) to rise and lower along the mast 14. A pair of left and right forks 12 for holding loads L, pallets 30, etc. are attached to the lift 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 lift 13.
The pallet 30 is a load-receiving platform on which the load L is placed. The pallet 30 is formed in the shape of a short rectangular plate 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, the forklift 1 includes, in addition to the above configuration, a drive unit 21, an operation unit 22, a display unit 23, a communication unit 28, a laser scanner 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 cargo handling motor (all not shown), which are various drive sources for the forklift 1. The travel motor drives the drive wheels of the wheels 15. The steering motor rotates the steering wheels of the wheels 15 (performs steering operations). The cargo handling motor is a drive source that performs the lifting and lowering of the lifting body 13 and the tilting of the mast 14.

The operation unit 22 is an operation means by which a driver performs various operations during, for example, manned (manual) driving. The operation unit 22 includes, for example, a steering wheel, pedals, levers, various buttons, etc., and outputs operation signals corresponding to the operations of these to the control unit 27.
The display unit 23 is, for example, a liquid crystal display, an organic electroluminescence display, or other 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 sending and receiving various information to and from a management server or the like.

The laser scanner 24 is an example of a measuring means according to the present invention, and acquires distance information within a predetermined scan area (measurement area) N in front of the vehicle body, and outputs the results to the control unit 27. The laser scanner 24 in this embodiment is a two-dimensional distance sensor (for example, a two-dimensional LiDAR (LASER Imaging Detection and Ranging)) having a planar scan area N that is approximately perpendicular to the left-right direction of the vehicle body 10.
The laser scanners 24 are disposed at a position higher than the height of the bed of a typical truck (e.g., 1.4 m) (see FIG. 4). The laser scanners 24 are also disposed on both the left and right sides of the vehicle body 11 (see FIG. 6). Each laser scanner 24 protrudes outward from the side of the vehicle so that the scan area N is not blocked by the load L even when the load L is loaded on the forks 12.
In the following, the two laser scanners 24 on the left and right may be identified by adding "R" to the end of the reference numeral for the right laser scanner 24R and "L" to the end of the reference numeral for the left laser scanner 24L (see Figure 6).

The position measurement device 25 measures the position of the forklift 1 itself. The self-position information acquired by the position measurement device 25 is transmitted to, for example, a management server and used to control the position of the forklift 1 itself. The specific configuration of the position measurement device 25 is not particularly limited, and it may, for example, be one that uses a Global Navigation Satellite System (GNSS). Alternatively, it may use a sensor that measures the traveling direction (such as an inertial measurement unit) and a traveling distance sensor to measure the position by sequentially integrating the direction and distance traveled over a very short period of time, or it may measure the position of the forklift 1 by using an optical sensor to detect reflectors (markers) placed at various locations in the work area and comparing the detected information 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. The storage unit 26 of this embodiment stores in advance a loading program 260 for executing the loading process (see FIG. 3 ), which will be described later.
The control unit 27 is configured by, 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 operation commands from the management server, loads programs stored in advance in the storage unit 26, and executes various processes in cooperation with the loaded programs.

[Loading process]
Next, the operation of the forklift 1 during loading operation will be described.
Fig. 3 is a flowchart showing the flow of the loading process. Fig. 4 to Fig. 7 are diagrams for explaining the loading process, of which Fig. 4 and Fig. 7 are side views of the forklift 1 during loading, Fig. 5 is a diagram for explaining an example of processing of point cloud data acquired by the laser scanner 24, Fig. 6 is a plan view of the forklift 1 during loading, and Fig. 8 is a plan view showing the swing operation of the forklift 1 when facing the loading platform 41.

The loading process is executed when the forklift 1 loads the load L onto the loading platform 41 of the truck 40. The loading process is executed by the control unit 27 of the forklift 1 reading and executing the loading program 260 from the storage unit 26.
In the following description, the side closer to the forklift 1 in the front-to-rear direction as viewed from the forklift 1 may be referred to as the "near side" and the side further away from the forklift 1 may be referred to as the "far side."

3, when the loading process is executed, the control unit 27 first starts a loading operation in which the loads L on the pallets 30 are picked up from, for example, a warehouse or the like, and are sequentially loaded onto the loading platform 41 of the truck 40 (step S1). Note that the loading process may be executed only during loading of the loads during the loading operation.
As shown in Figure 4, the truck 40 has the front gate (side gate) 42 of the loading platform 41 open, exposing the loading platform 41. Based on an operation command from the management server, the forklift 1 travels along a predetermined movement route, approaches the truck 40 from the side where the gate 42 is open, and loads the load L (pallet 30) at a predetermined position on the loading platform 41. When transporting the load L (pallet 30), the forklift 1 moves with the forks 12 positioned at a relatively low height (e.g., 300 mm from the ground). It is assumed that the forklift 1 and the loading platform 41 are both approximately horizontal.

In a loading and unloading operation, when the forklift 1 drives up to the vicinity of the truck 40 while holding the load L (pallet 30) with the forks 12, the vehicle body 10 is brought face-to-face with the side of the loading platform 41 on the side where the tailgate 42 is open in order to load the load L onto the loading platform 41. "Bringing the vehicle body 10 face-to-face with the side of the loading platform 41" means that, on the side of the truck 40, the front of the vehicle body 10 is faced toward the loading platform 41 (the side where the tailgate 42 is open).
In this embodiment, as shown in FIG. 8, the forklift 1 moves from the front or rear of the truck 40 along the vehicle length direction of the truck 40 (left and right direction in the figure), and then the vehicle body 10 is turned around beside the truck 40 by a so-called switchback, so that the vehicle body 10 faces directly to the side of the loading platform 41.

At this time, the control unit 27 causes the laser scanner 24 to scan the top of the loading platform 41 when turning the vehicle body 10 so as to face the side of the loading platform 41 (step S2).
Specifically, while the vehicle body 10 is turning, the control unit 27 operates the laser scanner 24 on the side closer to the loading platform 41 (the right side in FIG. 8 ) for a predetermined time (or turning angle) so that its scan area N covers the intended loading position 41P (see FIG. 6 ) of the load L on the loading platform 41. The control unit 27 then acquires distance information for the intended loading position 41P on the loading platform 41 and detects an object at this intended loading position 41P. The position (movement range) of the forklift 1 when operating the laser scanner 24 is set in advance based on the movement route.
It should be noted that the rotation of the vehicle body 10 at this time is sufficient as long as it moves toward facing the loading platform 41 directly (approaching a facing state), and it is not necessary for the vehicle body 10 and loading platform 41 to be facing each other exactly directly after this rotation.

Next, the control unit 27 determines whether or not an obstacle exists at the planned loading position 41P of the loading platform 41 based on the scan result of step S2 (step S3). Here, an obstacle refers to anything that exists at the planned loading position 41P of the loading platform 41, including a person (worker, etc.). However, for example, an obstacle smaller than a predetermined size may be set to be ignored (determined not to exist) as being negligible.
Then, if it is determined that an obstacle exists at the intended loading position 41P of the loading platform 41 (step S3; Yes), the control unit 27 stops the vehicle body 10, notifies the management server (or the driver) that there is an obstacle on the loading platform 41 (step S4), and then proceeds to step S11 described below.
The notification method in this case is not particularly limited, and may include transmitting a notification signal to the management server, displaying a warning on the display unit 23, or outputting a warning sound.

On the other hand, if it is determined in step S3 that there is no obstacle at the intended loading position 41P of the loading platform 41 (step S3; No), the control unit 27 scans the loading platform 41 again with the vehicle body 10 facing approximately directly to the side of the loading platform 41 (step S5).
4, the vehicle body 10 is positioned directly facing the loading platform 41 and stopped at a predetermined distance (e.g., 2 m, within the distance range where the detection accuracy of the laser scanner 24 is good) from the loading platform 41, and then scanned separately by the laser scanners 24 on both the left and right sides. Each scan area N includes the top surface 41a of the loading platform 41 and the tip (lower end) 42a of the tilt 42. This allows distance information within the scan area N, which includes the top surface 41a of the loading platform 41 and the entire tilt 42, to be obtained.

Next, the control unit 27 calculates the height of a predetermined position on the upper surface 41a of the loading platform 41 from the scan result of step S5, and determines the highest position among the calculated heights (step S6).
Specifically, in this step, as shown in Figure 5, the control unit 27 first determines a loading platform detection line L1 that detects (fits) the top surface 41a of the loading platform 41 and a tilt detection line L2 that detects the tilt 42 (surface) based on the point cloud data obtained by scanning.
The loading platform detection line L1 is obtained, for example, by taking the point cloud data obtained from the upper surface 41a of the loading platform 41 and distributing the data substantially horizontally at a height close to the actual loading platform 41 and applying a line detection algorithm to the point cloud data. The tilt detection line L2 is obtained, for example, by taking the point cloud data obtained from the tilt 42 and distributing the data substantially downward from the leading edge (the front end) of the loading platform 41 and applying a line detection algorithm to the point cloud data. The line detection algorithm is not particularly limited as long as it obtains a line that best fits the point cloud data, and may be, for example, a least-squares fitting method. In this embodiment, a wall detection line L3 (see FIG. 4 ) that detects the wall 43 rising above the loading platform 41 at the rear of the truck 40 and a ground detection line L4 that detects the substantially horizontal ground (floor) at the bottom of the front side are also obtained.
Next, the control unit 27 determines the intersection A between the platform detection line L1 and the tilt detection line L2. The intersection A represents the front end of the platform 41. Note that it is sufficient to determine the point at the front end of the platform 41, and for example, the intersection A may be determined as the frontmost point among the points located near (within a predetermined distance from) the platform detection line L1.

6, the control unit 27 sets P1 as a position on the loading platform detection line L1 that is a distance d1 behind the intersection point A, and P2 as a position that is a distance d2 behind the position P1. The distances d1 and d2 are set based on the size of the pallet 30 and the intended placement position 41P so that the four positions P1R, P2R, P1L, and P2L obtained from the two left and right laser scanners 24 appropriately correspond to, for example, the intended placement position 41P of the pallet 30 (e.g., the positions correspond to the four corners). For example, in this embodiment, the width of the pallet 30 is 900 to 1100 mm, and the corresponding distance d2 is set to 1000 mm.
Then, the control unit 27 determines the highest position among the four left and right positions P1R, P2R, P1L, and P2L.

Next, the control unit 27 raises the forks 12 to a position that is a predetermined height higher than the highest position among the four positions P1R, P2R, P1L, and P2L (step S7).
7A, the forks 12 are raised so that the upper surface 41a of the loading platform 41 and the bottom surface of the pallet 30 are separated by a margin of height h2 (e.g., 20 mm). The height h2 is not particularly limited, but is, for example, the minimum height that can reliably avoid contact between the loading platform 41 and the pallet 30 even when considering possible error factors.

Next, the control unit 27 calculates the position of the frontmost tip 42a (first portion) of the tilt 42 from the scan result of step S5 (step S8).
Specifically, in this step, as shown in Fig. 5, the control unit 27 first obtains point B, which is located closest to the point cloud data among points located near the tilt detection line L2 (points whose distance is within a predetermined range). If the tilt detection line L2 has not been obtained in step S6, it is obtained here.
Then, the obtained point B is set as the tip 42a of the tilt 42, and its position (coordinates) is obtained.

Next, as shown in FIG. 7B, the control unit 27 moves the vehicle body 10 forward to a position a predetermined distance in front of the position of the tip 42a of the tilt adjuster 42 determined in step S8 (step S9).
Since the position of the tip 42a of the swing-up lever 42 obtained in step S8 is a relative position (coordinates) from the laser scanner 24, here, the relative position from the front end of the vehicle body 11 is first obtained (the relative position of the laser scanner 24 on the vehicle body 10 is known). Then, the forklift 1 (vehicle body 10) is moved forward so that the front end of the vehicle body 11 and the tip 42a of the swing-up lever 42 are separated by a margin of distance d3. Distance d3 is not particularly limited, but is, for example, the minimum distance that can reliably avoid contact between the vehicle body 10 and the swing-up lever 42 even when assumed error factors are taken into consideration.

Next, the control unit 27 operates the forks 12 (reach, lift down, etc.) to load the load L (pallet 30) onto the loading platform 41 (step S10).

Next, the control unit 27 determines whether or not to terminate the loading process (step S11), and if it determines not to terminate it (step S11; No), it proceeds to the above-mentioned step S2 and continues the loading operation.
Then, when it is determined that the loading process should be ended, for example, due to the completion of the loading operation (step S11; Yes), the control unit 27 ends the loading process.

[Technical effect of this embodiment]
As described above, according to this embodiment, the vehicle body 10 is rotated to face the loading platform 41 while the laser scanner 24 is operated, and distance information within a predetermined range on the loading platform 41 (planned loading position 41P) is obtained.
This makes it possible to determine whether there is an obstacle at the intended loading position 41P. That is, by utilizing the rotation of the vehicle body 10, which is a preparatory operation for loading performed by facing the vehicle body 10 directly toward the loading platform 41, it is possible to determine whether there is an obstacle on the loading platform 41. Therefore, the work efficiency of the loading operation can be improved.

Furthermore, according to this embodiment, when it is determined that an obstacle exists on the loading platform 41, the display unit 23 or the like notifies the user of the determination result.
This allows the operator of the management server, the driver of the forklift 1, or other workers in the vicinity to be promptly notified of any problems in the work situation.

Furthermore, according to this embodiment, a two-dimensional distance sensor having a planar scan area N is used as the laser scanner 24 .
Therefore, the cost of measuring equipment can be reduced compared to using, for example, 3D-LiDAR, which is capable of three-dimensional measurement.

Furthermore, according to this embodiment, two laser scanners 24 are provided on both the left and right sides of the vehicle body 10 .
As a result, regardless of whether the vehicle body 10 turns left or right, by using the laser scanner 24 closer to the loading platform 41, measurements can be taken appropriately without the scanning area N being obstructed by cargo L or the like.

Furthermore, according to this embodiment, after the vehicle body 10 is substantially directly facing the loading platform 41 , the height of the loading platform 41 is detected by the laser scanner 24 .
In other words, the laser scanner 24 used for obstacle detection can also be used for height detection.

[others]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments (including modified examples).
For example, in the above embodiment, the forklift 1 moves along the length of the truck 40, and then the vehicle body 10 is turned in a switchback manner to face the loading platform 41. However, the turning of the forklift 1 is not limited to a switchback, as long as it faces the loading platform 41 directly. For example, as shown in Figure 9, the forklift 1 may move along the length of the truck 40 while keeping a small distance from the truck 40, and then turn toward the side of the truck 40. Even in this case, scanning is performed by the laser scanner 24 closest to the loading platform 41.

In addition, in the above embodiment, obstacles are detected at the intended loading position 41P on the loading platform 41, but the predetermined range on the loading platform 41 that is the detection target is not particularly limited to the intended loading position 41P of the load L during the current loading operation.

In addition, in the above embodiment, if it is determined in step S4 of the loading process that an obstacle is present on the loading platform 41, this determination result is reported. However, instead of (or in addition to) this reporting, the vehicle body 10 may be stopped for a predetermined period of time, after which the laser scanner 24 may again be used to check for the presence or absence of an obstacle at the intended loading position 41P.

In addition, while in the above embodiment laser scanners 24 are provided on both the left and right sides of the vehicle body 10, there are no particular limitations on the location or number of laser scanners 24. For example, they may be installed on only one side, or in the center of the left and right sides of the vehicle body 10. However, it is preferable that they be installed at a higher position than the loading area on which the load is placed. Furthermore, the measuring means according to the present invention is not limited to laser scanners as long as it is capable of acquiring distance information for a specified measurement area.

In the above embodiment, scanning is performed with the vehicle body 10 stopped in step S5 of the loading process, but scanning may also be performed while the vehicle body 10 is moving (for example, moving forward). In this case, however, it is of course necessary to correct the detection result by the amount of movement of the vehicle body 10.
In this case, the scan performed in step S5 may be integrated with the scan performed during rotation in step S2. That is, the scan results of step S2 may be used to perform the processes of steps S6 and S8.

In the above embodiment, an example has been described in which the load L is loaded onto the bed 41 of the truck 40. However, the loading portion according to the present invention is not limited to the bed of the truck, and may be, for example, a shelf (board) or the like, as long as it is a portion on which the load is placed.
Furthermore, the present invention is not limited to application when loading onto a loading platform (receiving section), but can be widely applied when approaching the loading platform, including when unloading from the loading platform.

In addition, in the above embodiment, the control unit 27 mounted on the forklift 1 performs various calculations, etc. However, control means 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 that can be operated by a person (including remote control) and a vehicle that can switch between being operated by a person and being unmanned. The present invention can also be used as an assist function for an unmanned 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. Forklift (cargo handling vehicle)
10 vehicle body 12 fork 23 display unit (notification means)
24 Laser scanner (measurement means)
27 Control unit (control means)
30 Pallet 40 Truck 41 Loading platform (loading section)
41a Upper surface 41P Planned placement position (predetermined range)
42 Tilt 42a Tip 260 Loading program A Intersection B Point (Tilt tip)
d1 Distance d2 Distance d3 Distance L Load L1 Platform detection line L2 Tilt detection line N Scan area (measurement area)
P1, P1R, P1L position P2, P2R, P2L position

Claims (8)

A drivable vehicle body,
a measuring means provided on the vehicle body and capable of acquiring distance information;
a control means;
Equipped with
the control means operates the measuring means while rotating the vehicle body so as to face a loading section on which a load is placed, and acquires distance information within a predetermined range above the loading section.
Loading vehicle. the control means determines whether or not an obstacle is present within the predetermined range based on distance information within the predetermined range.
The cargo handling vehicle according to claim 1. When the control means determines that an obstacle is present within the predetermined range, the control means notifies the determination result by the notification means.
The cargo handling vehicle according to claim 2. When the control means determines that an obstacle exists within the predetermined range, the control means acquires distance information within the predetermined range again by the measurement means after a predetermined time has elapsed.
The cargo handling vehicle according to claim 2. the measuring means is a two-dimensional distance sensor having a planar measurement area perpendicular to the left-right direction of the vehicle body;
The cargo handling vehicle according to any one of claims 1 to 4. The measuring means is provided in two units on both the left and right sides of the vehicle body.
The cargo handling vehicle according to any one of claims 1 to 5. the control means detects the height of the placement section by the measurement means after the vehicle body is substantially directly facing the placement section.
The cargo handling vehicle according to any one of claims 1 to 6. A drivable vehicle body,
a measuring means provided on the vehicle body and capable of acquiring distance information;
A computer of a loading vehicle comprising:
a control means for operating the measuring means while rotating the vehicle body so as to face a loading section on which a load is to be placed, and acquiring distance information within a predetermined range above the loading section;
A program that functions as a