Cargo handling vehicle and cargo handling program

Abstract

To performing suitably two-pallet taking.SOLUTION: A cargo handling vehicle 20 includes: a vehicle body 10; a pair of forks 12 mounted on the vehicle body 10 and inserted into openings 72 of a pallet 70 to hold the pallet 70; and a control unit 27. When the pair of forks 12 is inserted into the openings 72 of the two pallets 70 arranged side by side in a longitudinal direction at a time to pickup the two of the two pallets 70, the control unit 27 acquires distance information of the openings 72 of the two pallets 70 by the fork base end sensor 29, calculates relative positions of the two pallets 70 in a lateral direction on the basis of the acquired distance information, and determines, on the basis of the relative positions of the two pallets 70 in the lateral direction, whether or not two-pallet taking of the two pallets 70 is possible.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a cargo handling vehicle and a cargo handling program.

Background Art

[0002] Conventionally, cargo handling vehicles such as automated guided forklifts (AGF) that perform cargo handling operations are known. In the cargo handling vehicle described in Patent Document 1, when picking up a pallet with a fork, the opening (fork pocket) of the pallet is detected by a mounted sensor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when performing double-pallet picking to pick up two pallets arranged in the front and rear at once, if the two pallets are displaced left and right, the forks may not be properly inserted into the holes of the two pallets. It is useful if it is possible to determine whether double-pallet picking is possible before inserting the forks. The present invention has been made in view of the above circumstances, and an object thereof is to suitably execute double-pallet picking of pallets.

Means for Solving the Problems

[0005] The cargo handling vehicle according to the present invention is a fork mounted on the vehicle body and inserted into the hole of the cargo handling platform to hold the cargo handling platform, and an acquisition unit that acquires distance information of the holes of the two cargo handling platforms by a distance sensor when inserting the fork into the holes of the two cargo handling platforms arranged side by side in the front-rear direction at once to perform double-pallet picking of the two cargo handling platforms A calculation unit that calculates the relative position in the left - right direction of the two loading platforms based on the distance information acquired by the acquisition unit; A determination unit that determines whether it is possible to pick up two sheets of the two loading platforms based on the relative position in the left - right direction of the two loading platforms; It is provided with.

Effect of the Invention

[0006] According to the present invention, it is possible to suitably perform two - sheet picking of pallets.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0009] [Configuration of Cargo Handling System] FIG. 1 is a diagram showing the cargo handling vehicle 20 according to the present embodiment, and FIG. 2 is a block diagram showing the schematic control configuration of the cargo handling system 1 including the cargo handling vehicle 20. As shown in these figures, the handling system 1 performs predetermined handling operations (such as loading and unloading, transportation, stacking, picking, sorting, cargo alignment, and associated operations) in the work area by the handling vehicle 20. The handling system 1 is a system including, for example, a WMS (Warehouse Management System), a WES (Warehouse Execution System), a WCS (Warehouse Control System), and the like.

[0010] Specifically, the handling system 1 includes at least one handling vehicle 20 and a management server 30.

[0011] The handling vehicle 20 is a vehicle for performing handling operations, such as a forklift that can travel on the road without using rails or the like. The handling vehicle 20 holds the pallet 70 by a pair of left and right forks (handling parts) 12 provided on the vehicle body 10 and performs various handling operations. The handling vehicle 20 in the present embodiment is an automated guided forklift (AGF) that can operate automatically (unmanned) and operates based on an operation command or the like from the management server 30. The pallet (handling platform) 70 held by the handling vehicle 20 is a so-called half pallet with an axial length in the direction of inserting the forks 12 being about half of the normal one. The pallet 70 has two hole portions (fork pockets) 72 into which the pair of forks 12 are inserted.

[0012] Specifically, the handling vehicle 20 includes a vehicle body drive unit 21, a fork drive unit 28, an operation unit 22, a display unit 23, a communication unit 24, a position measurement device 25, a fork base end sensor 29, a side shift device 40, a storage unit 26, and a control unit 27.

[0013] The vehicle body drive unit 21 includes a traveling motor and a steering motor (both not shown in the figure), which are the drive sources of the vehicle body 10 of the cargo handling vehicle 20. The traveling motor drives the drive wheels among the wheels. The steering motor rotates (steers) the steering wheels among the wheels. Each motor is powered by a battery (not shown). Note that the drive source is not limited to a motor, and an internal combustion engine or the like may be used.

[0014] The fork drive unit 28 is a drive source for operating a pair of forks 12 protruding forward. The fork drive unit 28 of the present embodiment includes a tilt cylinder, a lift cylinder, and a reach cylinder (all not shown in the figure), which tilt, lift, and extend / retract (stretch) a pair of forks 12 with respect to the vehicle body 11. These cylinders are piston cylinders driven by hydraulic pressure (for example, oil pressure). The tilt cylinder tilts the lift body 13 or the mast 14 that supports a pair of forks 12 in the front-rear direction of the vehicle body. The lift cylinder raises and lowers the lift body 13 that holds a pair of forks 12 along the mast 14. The reach cylinder extends and retracts (stretches) a pair of forks 12 in the front-rear direction of the vehicle body 10 (substantially perpendicular to the mast 14).

[0015] The operation unit 22 is an operation means for a driver to perform various operations during manned (manual) driving. The operation unit 22 includes, for example, a steering wheel, pedals, levers, various buttons, etc., and outputs an operation signal corresponding to these operation contents to the control unit 27. The display unit 23 is, for example, a liquid crystal display, an organic electro-luminescence display, or other displays, and displays various information based on a display signal input from the control unit 27. Note that the display unit 23 may be a touch panel that also serves as a part of the operation unit 22, or may include a speaker capable of voice display (output). The communication unit 24 is a communication device capable of transmitting and receiving various information between the management server 30, other cargo handling vehicles 20, etc.

[0016] The position measuring device 25 measures the position of the loading vehicle 20 itself. The information on the self-position acquired by the position measuring device 25 is transmitted to, for example, the management server 30 and used for position control of the loading vehicle 20 itself. The specific configuration of the position measuring device 25 is not particularly limited, and for example, it may utilize GNSS (Global Navigation Satellite System), SLAM (Simultaneous Localization and Mapping) technology, indoor positioning (indoor mapping) technology, or other technologies.

[0017] The fork base end sensor 29 is an example of the distance sensor according to the present invention. It acquires distance information within the scan region (measurement region) N in front of the vehicle body and outputs the result to the control unit 27. The fork base end sensor 29 of the present embodiment is a two-dimensional distance sensor (for example, two-dimensional LiDAR (Laser Imaging Detection and Ranging)) having a planar scan region that is substantially orthogonal to the vertical direction along the mast 14. The fork base end sensor 29 is disposed at substantially the same height as the fork 12 (not particularly limited, for example, a height at which the scan region N is located slightly above the upper surface of the fork 12), and is disposed at the base end portions substantially at the center between the two forks 12 in the left-right direction (see FIG. 5). The fork base end sensor 29 of the present embodiment is used to detect the hole portion 72 of the pallet 70.

[0018] The side shift device 40 slides a pair of forks 12 in the vehicle width direction (left-right direction) with respect to the vehicle body 10. That is, the loading vehicle 20 is configured such that the center of a pair of forks 12 can be moved in the left-right direction with respect to the center of the vehicle body 10 by the side shift device 40.

[0019] The storage unit 26 is a memory composed of, for example, RAM (Random Access Memory) or ROM (Read Only Memory), stores various programs and data, and also functions as a working area for the control unit 27. The storage unit 26 of the present embodiment stores a program for executing the later-described loading process (see FIG. 3).

[0020] The control unit 27 is composed of, for example, a CPU (Central Processing Unit) or the like, and controls the operations of each part of the cargo handling vehicle 20. Specifically, the control unit 27 operates each part based on a control command from the management server 30 or the operation content of the operation unit 22, or develops a program pre-stored in the storage unit 26, and executes various processes in cooperation with the developed program.

[0021] The management server 30 centrally controls the cargo handling system 1 and is configured to be able to control the operation of the cargo handling vehicle 20. The management server 30 may be a personal computer, a smartphone, a tablet terminal, or the like. Specifically, the management server 30 includes an operation unit 31, a display unit 32, a communication unit 34, a storage unit 36, and a control unit 37.

[0022] The operation unit 31 is an operation means for an operator to perform various operations for operating the management server 30, and includes, for example, a pointing device such as a mouse or a keyboard. The display unit 32 is, for example, a liquid crystal display, an organic electro-luminescence display, or other displays. The display unit 32 displays various information based on a display signal input from the control unit 37. Further, the display unit 32 may be a touch panel that also serves as at least a part of the operation unit 31. The communication unit 34 is a communication device capable of transmitting and receiving various information to and from each cargo handling vehicle 20.

[0023] The storage unit 36 is a memory composed of, for example, a RAM (Random Access Memory), a ROM (Read Only Memory), or the like, stores various programs and data, and also functions as a working area for the control unit 37. The control unit 37 is composed of, for example, a CPU (Central Processing Unit) or the like, and controls the operations of each part of the management server 30. Specifically, based on the operation content of the operation unit 31 and the like, the control unit 37 expands a program stored in advance in the storage unit 36, and executes various processes in cooperation with the expanded program.

[0024] [Two-pallet picking process] Subsequently, the two-pallet picking process in which the handling vehicle 20 picks up two pallets 70 at a time will be described. FIG. 3 is a flowchart showing the flow of the two-pallet picking process. FIGS. 4 and 5 are diagrams for explaining the two-pallet picking process. FIG. 6 is a diagram showing the point cloud data acquired by the fork base end sensor 29 and an example of its processing, and shows a case where two-pallet picking is possible.

[0025] The two-pallet picking process is a process executed when the handling vehicle 20 simultaneously holds two pallets 70 with the forks 12 (at once). This two-pallet picking process is executed by the control unit 27 of the handling vehicle 20 reading and expanding the corresponding program from the storage unit 26. The program may be a part of a handling program executed for a predetermined handling operation. Here, for example, it is assumed that two identical pallets 70 placed on the pallet table T are picked up. The two pallets 70 are arranged in the direction of the hole portions 72 and are placed in a state where at least a part of the two hole portions 72 of each other overlap. In the following description, the "front side" and the "rear side" refer to the side closer to and farther from the handling vehicle 20 in the front-rear direction. Also, among the two pallets 70, the one on the near side may be labeled "F" and the one on the far side may be labeled "B" at the end of each symbol to distinguish them.

[0026] As shown in FIG. 3, when the two-pallet picking process is executed, first, the control unit 27 controls the vehicle body 10 to face the two arranged pallets 70 (step S1; FIGS. 4 and 5). The term "facing each other" for the two pallets 70 means a state in which the vehicle body 10 is positioned in the juxtaposed direction with respect to the two pallets 70 and the pair of forks 12 are directed toward the two pallets 70. Here, the handling vehicle 20 faces the two pallets 70, for example, by aligning the center in the left-right direction with the front pallet 70F.

[0027] Next, the control unit 27 scans the pallet 70 with the fork base end sensor 29 and detects the hole portion 72 (step S2). Specifically, the control unit 27 raises and lowers the fork 12 (fork base end sensor 29) to the height of the pallet 70 as necessary and then scans the pallet 70 with the fork base end sensor 29. Thereby, the control unit 27 acquires distance information (point cloud data) in the horizontal plane of each pallet 70 including the hole portion 72, which is included in the scan area N of the fork base end sensor 29.

[0028] Next, the control unit 27 calculates the relative position (displacement amount) in the left-right direction (vehicle width direction) of the two pallets 70 based on the distance information acquired in step S2 (step S3). Specifically, as shown in FIG. 6, for example, the control unit 27 obtains the maximum displacement amount dT in the left-right direction based on the pallet inner wall surface data D1 that detects the inner wall surfaces on the outer sides in the left-right direction of each hole portion 72 among the point cloud data obtained by the scan in step S2. The pallet inner wall surface data D1 can be extracted as point cloud data extending in the depth direction. Since the pallet inner wall surface data D1 detects the inner wall surfaces on the outer sides in the left-right direction of each hole portion 72 of the two pallets 70, the displacement amount dT in the left-right direction corresponds to the displacement amount in the left-right direction of the two pallets 70.

[0029] Next, the control unit 27 determines whether or not the displacement amount dT obtained in step S3 is within the threshold value (step S4). The threshold value is preset and stored in the storage unit 26 in association with, for example, the types of the pallets 70. This threshold value is set as the maximum amount of positional deviation that allows the fork 12 to be inserted into the hole portion 72, based on, for example, the width dimensions of the hole portion 72 and the fork 12. That is, in this step, it is determined whether it is possible to pick up two pallets 70 at a time. Note that the threshold value only needs to be able to determine whether it is possible to pick up two pallets 70 with respect to the lateral positional deviation between the two pallets 70. For example, a sufficient margin may be provided, or the user may adjust it as appropriate.

[0030] Note that instead of (or in addition to) calculating the amount of positional deviation dT, after estimating the position of the hole portion 72, the insertion position of the fork 12, etc., it may be determined based on these whether it is possible to pick up two pallets 70 at a time. In this case, first, the control unit 27 obtains a front surface estimation line L1 that detects (fits) the front surface of the pallet 70F based on the point cloud data obtained by the scan in step S2. The front surface estimation line L1 is obtained, for example, by applying a predetermined straight line detection algorithm to the data distributed on the frontmost side among the point cloud data. The straight line detection algorithm is not particularly limited as long as it can obtain a straight line that best fits the point cloud data, and may be, for example, a method of fitting using the least squares method. Next, the control unit 27 obtains a pallet estimation line L2 that estimates the position and shape of the pallet 70F based on the shape data of the pallet 70. Specifically, first, the control unit 27 collates the numerical information on the width of the hole portion 72 with the point cloud data to obtain the opening end of the hole portion 72 on the front surface estimation line L1. Then, the control unit 27 obtains an estimation line of the hole portion 72 as a line orthogonal to the front surface estimation line L1 passing through the opening end, and obtains a pallet estimation line L2 that estimates the planar shape of the entire pallet 70F including this. Note that the necessary shape data of the pallet 70 is stored in the storage unit 26 in advance. Next, the control unit 27 obtains a fork prediction line L3 representing the predicted position (lateral position) of the fork 12 when the vehicle body 10 moves forward or the fork 12 extends. The fork prediction line L3 is a line obtained by extending the width of the fork 12 in the depth direction, and is obtained from information on the relative position between the known fork 12 and the fork base end sensor 29 and information on the width dimension of the fork 12. These pieces of information are stored in the storage unit 26 in advance. Then, when the fork prediction line L3 intersects with the pallet estimation line L2 or the inner wall surface data D1 of the pallet, the control unit 27 may determine that the fork 12 interferes with the pallet 70, that is, it is determined that the two - pallet pick - up of the two pallets 70 is not possible.

[0031] In step S4, when it is determined that the displacement amount between the two pallets 70 is within the threshold value (step S4; Yes), the control unit 27 picks up two pallets 70 (step S5). Here, the control unit 27 moves the vehicle body 10 forward or extends the fork 12, and inserts each fork 12 through the hole portions 72 of the two pallets 70 at once. Then, the control unit 27 raises (lifts up) the fork 12 to pick up the two pallets 70 (see FIG. 1). After that, the control unit 27 ends the two - pallet pick - up process and executes, for example, the process of a predetermined handling operation to be executed thereafter.

[0032] On the other hand, in step S4, when it is determined that the displacement amount between the two pallets 70 is not within the threshold value (step S4; No), the control unit 27 determines whether it is possible to correct the displacement between the two pallets 70 by side - shifting the fork 12 left and right (step S6). Here, for example, when the displacement amount between the two pallets 70 exceeds the upper limit of the movement amount of the fork 12 by the side - shift device 40, the control unit 27 determines that the displacement cannot be corrected by side - shifting.

[0033] In step S6, when it is determined that the positional deviation between the two pallets 70 can be corrected by side shift (step S6; Yes), the control unit 27 corrects the positional deviation between the two pallets 70 by side shift and then picks up the two pallets 70 (step S7). Specifically, first, the control unit 27 moves the vehicle body 10 forward and raises (lifts up) the fork 12 to hold only the front pallet 70F with the fork 12. Then, the control unit 27 moves the fork 12 left and right by the side shift device 40 to move the pallet 70F in the direction in which the amount of positional deviation becomes smaller. In this way, after suppressing the amount of positional deviation between the two pallets 70 within the threshold value, the two pallets 70 are picked up. Note that after correcting the amount of positional deviation, the scan by the fork base end sensor 29 (after step S2) may be executed again. Thereafter, the control unit 27 terminates the two-pallet picking process and executes, for example, the process of a predetermined handling operation to be executed thereafter.

[0034] On the other hand, in step S6, when it is determined that the positional deviation between the two pallets 70 cannot be corrected by side shift (step S6; No), the control unit 27 performs a warning output warning that the two-pallet picking of the two pallets 70 is not executable (step S8). Here, the control unit 27 stops the vehicle body 10 and causes the display unit 23 to display a warning or output a warning sound to notify the surrounding workers and the management server 30 that the two-pallet picking is not executable. The output (notification) mode in this case is not particularly limited, and for example, a rotating lamp may be lit. Then, the control unit 27 terminates the two-pallet picking process. However, for example, when the two-pallet picking is instructed to be re-executed after measures such as the operator correcting the position of the pallet 70 are taken, the control unit 27 may shift the process to step S1 or S2 and continue the two-pallet picking process.

[0035] [Technical effects of this embodiment] As described above, according to the present embodiment, when the forks 12 are inserted into the hole portions 72 of the two pallets 70 at once to pick up two pallets 70, the fork base end sensor 29 acquires the distance information of the hole portions 72 of the two pallets 70, and based on the distance information, the relative position of the two pallets 70 in the left - right direction (vehicle width direction) is calculated. Then, based on the relative position, it is determined whether it is possible to pick up two pallets 70. Thereby, interference between the forks 12 and the pallets 70 caused by the positional deviation of the two pallets 70 in the left - right direction can be suppressed. Therefore, it is possible to suitably execute picking up two pallets 70. As a result, the risk of failure in picking up two pallets can be suppressed, and the work efficiency can be improved.

[0036] Further, according to the present embodiment, the amount of positional deviation dT in the left - right direction of the two pallets 70 calculated based on the distance information is compared with a threshold value set based on the width dimension of the hole portion 72 and the width dimension of the forks 12, and it is determined whether it is possible to pick up two pallets. Thereby, from the viewpoint of interference between the forks 12 and the pallets 70, the amount of positional deviation dT can be appropriately evaluated.

[0037] Also, according to the present embodiment, when it is determined that it is not possible to pick up two pallets, the side - shift device 40 moves the front - side pallet 70F in the direction in which the amount of positional deviation dT becomes smaller. Thereby, within the moving range of the side - shift device 40, the positional deviation of the two pallets 70 can be suitably corrected and picking up two pallets can be executed.

[0038] [Others] Although the embodiments of the present invention have been described above, the present invention is not limited to the above - described embodiments (including modification examples).

[0039] For example, in the above embodiment, as an example of the distance sensor according to the present invention, the fork base sensor 29 mounted on the base end portion of the fork 12 was exemplified. However, the distance sensor according to the present invention is not particularly limited in terms of the type of sensor or the like as long as it can acquire the distance information of the hole portion 72 when taking two pallets 70 at a time.

[0040] Further, in the above embodiment, the control unit 27 mounted on the material handling vehicle 20 performs various calculations and the like. However, a control means provided outside the material handling vehicle 20 (for example, the management server 30) may perform calculations based on the information transmitted from the material handling vehicle 20 and transmit the result to the material handling vehicle 20. Also, the material handling vehicle 20 and the management server 30 may cooperate in other modes to perform various controls.

[0041] Further, in the above embodiment, the material handling vehicle 20 is an unmanned vehicle (unmanned forklift) that can operate without a driver. However, the material handling vehicle according to the present invention includes those that can be manned (including remote operation) or those that can switch between manned operation and unmanned operation. Also, the present invention can be used as an assist function for manned operation. Moreover, the material handling vehicle according to the present invention is not limited to a forklift as long as it can hold a load with a fork (or something similar) and travel, and includes, for example, an automated guided vehicle (AGV) that travels without a driver. In addition, the details shown in the above embodiment can be appropriately changed without departing from the gist of the invention.

Explanation of Reference Numerals

[0042] 1 Material handling system 10 Vehicle body 12 Fork 20 Material handling vehicle 26 Storage unit 27 Control unit (acquisition unit, calculation unit, determination unit) 29 Fork base sensor (distance sensor) 30 Management server 40 Side shift device 70 Pallets (loading and unloading platform) Pallet on the front side of 70F Pallet on the rear side of 70B 72 Hole part D1 Pallet inner wall surface data dT Amount of displacement L1 Front estimated line L2 Pallet estimated line L3 Fork prediction line N Scan area

Claims

1. A fork mounted on a vehicle body and inserted into a hole of a loading platform to hold the loading platform, When the fork is inserted through the holes of two loading platforms arranged side by side in the front-rear direction at once to pick up two of the loading platforms, an acquisition unit that acquires distance information of the holes of the two loading platforms by a distance sensor; A calculation unit that calculates the relative position in the left-right direction of the two loading platforms based on the distance information acquired by the acquisition unit; A determination unit that determines whether it is possible to pick up two of the loading platforms based on the relative position in the left-right direction of the two loading platforms; A loading vehicle comprising the above.

2. The calculation unit calculates the amount of displacement in the left-right direction of the two loading platforms, The determination unit compares the amount of displacement calculated by the calculation unit with a threshold value preset based on the width dimension of the hole portion and the width dimension of the fork, and determines whether it is possible to pick up two at a time. The loading vehicle according to Claim 1.

3. When the determination unit determines that it is not possible to pick up two of the loading platforms, the operation of the vehicle body is stopped, and a warning output is performed to warn that it is not possible to pick up two at a time. The loading vehicle according to Claim 1 or 2.

4. The fork is provided with a side shift device that can move in the left-right direction with respect to the vehicle body. When the determination unit determines that it is not possible to pick up two at a time, with the front loading platform of the two loading platforms held by the fork, the side shift device moves the front loading platform in the direction in which the amount of displacement becomes smaller. The loading vehicle according to Claim 2.

5. The loading vehicle is an unmanned vehicle that can operate unmanned. The loading vehicle according to Claim 1.

6. A computer of a loading vehicle including a vehicle body, a distance sensor, and a fork mounted on the vehicle body and inserted into a hole of a loading platform to hold the loading platform, When the fork is inserted through the holes of two loading platforms arranged side by side in the front-rear direction at once to pick up two of the loading platforms, an acquisition unit that acquires distance information of the holes of the two loading platforms by the distance sensor, A calculation unit that calculates the relative position in the left-right direction of the two loading platforms based on the distance information acquired by the acquisition unit, A determination unit that determines whether it is possible to pick up two of the loading platforms based on the relative position in the left-right direction of the two loading platforms, A loading program that functions as the above.

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