Cargo picking determination device, cargo handling vehicle, and program

Abstract

To improve work efficiency of cargo handling works.SOLUTION: A forklift 1 comprises a laser scanner 24 capable of acquiring distance information to a pallet 30 with a pocket 32 at the front 32 and a control part 27. The control part 27 obtains a front face detection line L1 detecting a front face 31 based on the acquired distance information by the laser scanner 24, obtains a hole estimation line L2 estimating the position of the pocket 32 to the front face detection line L1 based on the positional relation between the front face 31 and the pocket 32, and determines the interference between a fork 12 and the pocket 32 based on the hole estimation line L2.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a load determination device, a material handling vehicle, and a program.

Background Art

[0002] When transporting a pallet (material handling platform) with a material handling vehicle such as a forklift, the forks (claw parts) are inserted into the pockets of the pallet and lifted up. When picking up this pallet, for example, if the vehicle body is not facing the pallet directly, the forks may interfere with the entrance or inner wall of the pocket. When such interference between the forks and the pallet occurs, there is a risk that the pallet cannot be held or is damaged, resulting in a decrease in work efficiency.

[0003] Therefore, in the technique described in Patent Document 1, for example, distance data to the front surface of the pallet is acquired by a laser sensor, and the position of the inner wall (side wall) of the pocket is specified based on the acquired distance data.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in a four-way pierced pallet or the like with pockets not only on the front surface but also on the side surface, the inner wall of the pocket may not be a uniform plane. With such a pallet, the position of the inner wall of the pocket cannot be suitably specified, and as a result, interference between the forks and the pallet may occur, leading to a decrease in work efficiency. The present invention has been made in view of the above circumstances, and an object thereof is to improve the work efficiency of material handling operations.

Means for Solving the Problems

[0006] The cargo handling determination device according to the present invention is A measuring means capable of acquiring distance information to a loading platform having a hole in the front, A detection means that determines the front detection line that detected the front surface based on the distance information acquired by the measurement means, An estimation means for determining a hole estimation line by estimating the position of the hole relative to the front surface detection line based on the positional relationship between the front surface and the hole, A determination means for determining interference between the claw portion inserted into the hole and the hole, based on the hole estimation line, Equipped with 、 The estimation means is, Based on the distance information, the opening end of the hole on the front detection line is determined. The hole estimation line is determined as a line that passes through the open end of the hole and is perpendicular to the front detection line. .

[0007] The program according to the present invention is A computer for a cargo handling determination device equipped with a measuring means capable of acquiring distance information to a loading platform having a hole in the front, A detection means that determines the front detection line detected on the front surface based on the distance information acquired by the measurement means, Estimation means for determining a hole estimation line by estimating the position of the hole relative to the front detection line, based on the positional relationship between the front surface and the hole. Based on the hole estimation line, interference between the claw portion inserted into the hole and the hole is determined. Judgment means, To function as 、 The estimation means is, Based on the distance information, the opening end of the hole on the front detection line is determined. The hole estimation line is determined as a line that passes through the open end of the hole and is perpendicular to the front detection line. . [Effects of the Invention]

[0008] According to the present invention, the work efficiency of cargo handling operations can be improved. [Brief explanation of the drawing]

[0009] [Figure 1]It is a side view of a forklift according to an embodiment. [Figure 2] It is a block diagram showing a schematic control configuration of a forklift according to an embodiment. [Figure 3] It is a flowchart showing the flow of load taking determination processing according to an embodiment. [Figure 4] It is a diagram for explaining load taking determination processing according to an embodiment. [Figure 5] It is a diagram for explaining load taking determination processing according to an embodiment. [Figure 6] It is a diagram for explaining load taking determination processing according to an embodiment. [Figure 7] It is a diagram showing a four-way stabbed pallet. [Figure 8] It is a diagram for explaining processing when there are obstacles in front of and behind the pallet. [Figure 9] It is a diagram for explaining processing when there are obstacles in front of and behind the pallet.

Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0011] [Configuration of Forklift] 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 loading and unloading vehicle according to the present invention, and performs a loading and unloading operation including loading and unloading of a pallet 30 (or a load L placed thereon) and its conveyance. Further, the forklift 1 is, although not particularly limited, an automated guided forklift (AGF: Automated Guided Forklift) that can operate unmanned (automatically), and performs a predetermined loading and unloading operation based on an operation command or the like from a management server (not shown).

[0012] Specifically, the forklift 1's body 10 comprises a vehicle body 11, forks (tines) 12, a lifting body (lift) 13, a mast 14, and wheels 15. The mast 14 is located in front of the vehicle body 11 and is driven by a power source (not shown) to tilt forward and backward relative to the vehicle body 11. The lifting body 13 is driven by a power source (not shown) to move up and down along the mast 14. The lifting body 13 is fitted with a pair of left and right forks 12 for holding loads L, pallets 30, etc. The pair of forks 12 can tilt and move up and down relative to the vehicle body 11, as well as move forward and backward, due to the drive of the mast 14 and the lifting body 13, etc. The pallet 30 is a loading platform on which the load L is placed. The pallet 30 is formed in the shape of a short rectangular plate and has two pockets (holes) 32 into which a pair of forks 12 are inserted.

[0013] Figure 2 is a block diagram showing the schematic control configuration of forklift 1. As shown in this figure, in addition to the above configuration, the forklift 1 includes a drive unit 21, an operation unit 22, a display unit 23, a communication unit 28, a laser scanner 24, a position measuring device 25, a storage unit 26, and a control unit 27. The load picking determination device according to the present invention includes a laser scanner 24 and a control unit 27.

[0014] The drive unit 21 includes various drive sources for the forklift 1, such as a travel motor, a steering motor, and a cargo handling motor (all not shown). The travel motor drives the drive wheels among the wheels 15. The steering motor rotates the steering wheels among the wheels 15 (steering action). The cargo handling motor is the drive source that performs the raising and lowering of the lifting body 13 and the tilting of the mast 14.

[0015] The control unit 22 is, for example, an operating means used by the driver to perform various operations during manned (manual) operation. The control unit 22 includes, for example, a steering wheel, pedals, levers, various buttons, etc., and outputs operation signals corresponding to the content of these operations to the control unit 27. The display unit 23 is, for example, a liquid crystal display, an organic electroluminescent display, or other display, and displays various information based on display signals input from the control unit 27. The display unit 23 may also be a touch panel that also functions as part of the operation unit 22. The display unit 23 may also include an audio output unit capable of outputting sound. The communication unit 28 is a communication device capable of sending and receiving various types of information with the management server and the like.

[0016] The laser scanner 24 is an example of a measurement 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 result 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 substantially orthogonal to the vertical direction of the vehicle body 10. The laser scanner 24 is positioned at approximately the same height as the forks 12 (more precisely, at a height where the scanning area N is slightly above the top surface of the forks 12 (for example, 10 mm)) and is positioned approximately in the center between the two forks 12 (see Figure 4).

[0017] The position measuring device 25 measures the position of the forklift 1 itself. The self-position information acquired by the position measuring device 25 is transmitted to a management server, for example, and used for position control of the forklift 1 itself. The specific configuration of the position measuring device 25 is not particularly limited; for example, it may utilize GNSS (Global Navigation Satellite System). Alternatively, it may use a sensor that measures the direction of travel (such as an inertial measuring device) and a distance sensor to sequentially accumulate the direction and distance traveled in a short period of time to measure the position, or it may detect reflectors (markers) placed at various locations in the work area with an optical sensor and measure the position of the forklift 1 by comparing it with pre-set reflector placement information.

[0018] The storage unit 26 is a memory composed of, for example, RAM (Random Access Memory) or ROM (Read Only Memory), and stores various programs and data, as well as functioning as a work area for the control unit 27. In this embodiment, the storage unit 26 pre-stores a cargo pickup determination program 260 for executing the cargo pickup determination process (see Figure 3) described later. The control unit 27 is composed of, 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, and deploys programs pre-stored in the storage unit 26 and executes various processes in cooperation with the deployed programs.

[0019] [Cargo pick-up determination process] Next, we will explain the operation of forklift 1 when it performs a load handling determination process during cargo handling operations. Figure 3 is a flowchart illustrating the flow of the cargo retrieval determination process. Figures 4 to 6 are diagrams illustrating the cargo retrieval determination process. Figures 4 and 5 are plan and side views of the forklift 1 during pallet retrieval, and Figure 6 is a diagram illustrating an example of the processing of point cloud data acquired by the laser scanner 24. The point cloud data example in Figure 6 is for a four-sided pallet.

[0020] The cargo pickup determination process is executed when the forklift 1 picks up the pallet 30 (by inserting the forks 12 into the pockets 32 to pick it up). This cargo pickup determination process is executed when the control unit 27 of the forklift 1 reads the cargo pickup determination program 260 from the storage unit 26 and loads it. In the following, when viewed from forklift 1, the side closer to forklift 1 in the front-to-back direction (depth direction) may be referred to as the "front side," and the side further away may be referred to as the "back side."

[0021] As shown in Figure 3, when the cargo retrieval determination process is executed, the control unit 27 first starts cargo handling operations, for example, retrieving and transporting a pallet 30 from a pallet stand 41 in the warehouse (step S1). The forklift 1 travels along a predetermined movement path and performs cargo handling operations based on the operation command from the management server. Note that the cargo retrieval determination process may be executed only when retrieving the pallet 30 during the cargo handling operations.

[0022] Next, the control unit 27 moves in front of the pallet stand 41 to unload the pallet 30 (step S2; Figure 4). The pallet stand 41 is the exit point for the roller conveyor 40 that transports the pallets 30. The roller conveyor 40 transports the pallets 30 toward the pallet stand 41, which is the exit point, and guides the pallets 30 with guide guides 42 so that they are in a predetermined position and orientation on the pallet stand 41, and stops them with stoppers 43. As a result, the pallets 30 are secured to the pallet stand 41 with the two pockets 32 exposed on the front surface 31. Here, the control unit 27 moves the forklift 1 so that the vehicle body 10 faces the pallet stand 41 directly. More specifically, the forklift 1 is moved in front of the pallet stand 41 (i.e., the front 31 of the pallet 30) so that it faces the pallet stand 41 directly, based on the specified XY coordinates (coordinates in the horizontal plane) and angle in the XY plane (orientation of the vehicle body 10). From the perspective of the forklift 1 stopped in front of the pallet stand 41, the X direction is the left-right direction, and the Y direction is the front-back direction (depth direction). It is assumed that both the forklift 1 and the pallet stand 41 (pallet 30) are approximately horizontal.

[0023] Next, the control unit 27 raises the forks 12 to the height of the pallet 30 (pocket 32) on the pallet stand 41 (step S3; Figure 5). The height of the pallet 30 on the pallet stand 41 is set (input) in advance. However, for example, a sensor for detecting the pallet may be provided at the tip of the fork 12, and the fork 12 may be raised to the height at which the sensor detects the pallet 30 (pocket 32). In this case, the laser scanner 24, which is at approximately the same height as the fork 12, should be positioned at the same height as the pocket 32 ​​so that it can detect the pocket 32. In other words, the scan area N of the laser scanner 24 should include the pocket 32 ​​of the pallet 30.

[0024] Next, the control unit 27 scans the pallet 30 with the laser scanner 24 (step S4). Specifically, the control unit 27 operates the laser scanner 24 to acquire distance information (point cloud data) in the horizontal plane of the pallet 30, including the pocket 32, which is included in the scan area N.

[0025] Next, the control unit 27 detects the pockets 32 of the pallet 30 based on the scan results of step S4 (step S5). Specifically, in this step, as shown in Figure 6, the control unit 27 first determines a front detection line L1 that detects (fits) the front surface 31 of the pallet 30 based on the point cloud data obtained by scanning. The front detection line L1 is obtained, for example, by selecting the point cloud data distributed on the closest side (lower side in Figure 6) from the point cloud data obtained from the front surface 31 and applying a line detection algorithm to this point cloud data. The line detection algorithm is not particularly limited as long as it obtains the line that best fits the point cloud data, and for example, a fitting method using the least squares method may also be used. Next, the control unit 27 determines the estimated hole line L2, which estimates the position of the pocket 32 ​​relative to the front detection line L1, based on the positional relationship between the front surface 31 and the pocket 32 ​​(inner wall). Specifically, the control unit 27 compares the numerical information of the width w1 of the pocket 32 ​​with the point cloud data to determine the opening end of the pocket 32 ​​on the front detection line L1. The numerical information of the width w1 is stored in the storage unit 26 in advance. Then, the control unit 27 determines the estimated hole line L2 as a line that passes through the opening end and is perpendicular to the front detection line L1. In this embodiment, based on the shape data of the pallet 30 (for example, numerical data such as the total width on the left and right, the depth from front to back, and the position of the pocket 32 ​​on the front surface 31), side detection lines L3 that detect both the left and right sides and a rear detection line L4 that detects the rear side are also determined. The shape data of the pallet 30, including the width w1 of the pocket 32, is stored in the storage unit 26 in advance. Furthermore, when determining the opening end of the pocket 32 ​​on the front detection line L1, the numerical information of the width w1 of the pocket 32 ​​may not be used. Instead, for example, it may be determined by using a point located near the front detection line L1 (a point within a predetermined distance) that is adjacent to the gap corresponding to the pocket 32. However, since the actual opening end of the pocket 32 ​​may have damaged or rounded corners, it is preferable to use the numerical information of the width w1 as in this embodiment.

[0026] Next, the control unit 27 determines, based on the detection result of step S5, whether or not the pocket 32 ​​of the pallet 30 and the fork 12 interfere with each other (step S6). Here, the control unit 27 determines a fork prediction line L5 that represents the predicted position (left-right position) of the fork 12 when the vehicle body 10 is moved forward or the fork 12 is extended. The fork prediction line L5 is a line that extends the width of the fork 12 in the depth direction and is determined from the known relative position information between the fork 12 and the laser scanner 24. The control unit 27 then determines that the fork 12 will interfere with the pocket 32 ​​when the fork prediction line L5 and the hole estimation line L2 intersect. If the control unit 27 determines that the fork 12 and the pocket 32 ​​will interfere with each other (step S6; Yes), it stops the vehicle body 10 and notifies the management server (or the driver) that the fork 12 and the pocket 32 ​​will interfere (the fork 12 should not be inserted into the pocket 32 ​​in the current state of the vehicle body 10) (step S7), and then proceeds to step S10 described below. The notification method in this case is not particularly limited; a notification signal may be sent to the management server, or a warning display may be shown on the display unit 23, or a warning sound may be output. Furthermore, after notification, the orientation of the vehicle body 10 may be autonomously corrected to avoid interference.

[0027] On the other hand, if in step S6 it is determined that the fork 12 and the pocket 32 ​​do not interfere with each other (step S6; No), the control unit 27 moves the vehicle body 10 forward or extends the fork 12 to insert the fork 12 into the pocket 32 ​​and pick up the pallet 30 from the pallet stand 41 (step S8).

[0028] Next, the control unit 27 transports the pallet 30 and performs the predetermined cargo handling operation (step S9). Next, the control unit 27 determines whether or not to terminate the cargo handling determination process (step S10). If it determines not to terminate the process (step S10; No), it proceeds to step S2 described above and continues the cargo handling operation. Then, if it is determined that the cargo handling operation should be terminated, for example, due to the completion of cargo handling operations (step S10; Yes), the control unit 27 terminates the cargo handling operation.

[0029] [Technical effects of this embodiment] As described above, according to this embodiment, distance information to the pallet 30 having a pocket 32 ​​on the front surface 31 is acquired by the laser scanner 24, a front surface detection line L1 is determined based on this distance information to detect the front surface 31, a hole estimation line L2 is determined based on the positional relationship between the front surface 31 and the pocket 32 ​​(inner wall) to estimate the position of the pocket 32 ​​relative to the front surface detection line L1, and interference between the fork 12 and the pocket 32 ​​is determined based on this hole estimation line L2. This allows for the appropriate detection of the pocket 32's position and the determination of interference with the fork 12. In other words, in conventional methods that directly detect the inner wall of the pocket using distance data acquired by a sensor, for example, in the case of a four-sided pallet 30 with pockets 32 on the left and right sides as shown in Figure 7, the position of the pocket 32 ​​may not be appropriately detected because the inner wall of the pocket is not a uniform plane. In this respect, according to this embodiment, the front surface 31 of the pallet 30 is detected based on the acquired distance information, and the position of the pocket 32 ​​is set (estimated) relative to this front surface detection line L1. Therefore, even if the inner wall of the pocket 32 ​​is not a uniform plane, the position of the pocket 32 ​​can be appropriately detected and interference with the fork 12 can be determined. Consequently, interference between the fork 12 and the pallet 30 can be appropriately avoided, and the work efficiency of cargo handling operations can be improved.

[0030] Furthermore, according to this embodiment, since the hole estimation line L2 is determined as a line perpendicular to the front detection line L1, the inner wall of the pocket 32 ​​can be suitably detected as the hole estimation line L2. Furthermore, according to this embodiment, the position of the hole estimation line L2 on the front detection line L1 is determined based on the numerical information of the width w1 of the pocket 32 ​​that has been stored in advance, so the inner wall of the pocket 32 ​​can be detected more preferably as the hole estimation line L2.

[0031] Furthermore, according to this embodiment, a two-dimensional distance sensor having a planar scanning area N aligned in the left-right direction (i.e., the width direction of the pallet 30) is used as the laser scanner 24. Therefore, compared to using, for example, a 3D-LiDAR capable of three-dimensional measurement, it is possible to suitably acquire distance information of the front surface 31 of the pallet 30 while keeping the cost of the measuring instrument down.

[0032] Furthermore, according to this embodiment, if it is determined that the fork 12 and the pocket 32 ​​are interfering with each other, the result of this determination is notified by the display unit 23 or the like. This allows for the prompt notification of any malfunctions in the work environment to the operator of the management server, the driver of forklift 1, or other workers in the vicinity.

[0033] [others] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments (including modifications). For example, obstacles located in front of or behind the pallet 30 may be detected based on the detection result of the pallet 30 shape. Specifically, for example, as shown in Figures 8 and 9, if point cloud data P1 is detected in front of the front detection line L1, it may be determined that an obstacle B1 exists in front of the pallet 30. Alternatively, if point cloud data P2 is detected behind the rear surface (or presumed rear surface) of the pallet 30, it may be determined that an obstacle B2 exists behind the pallet 30. Furthermore, if point cloud data P2 is detected in front of the rear surface (or presumed rear surface) of the pallet 30, it may be determined that the fork 12 (scan area N) and the pallet 30 are tilted relative to each other in the front-to-back direction, and that the fork 12 is interfering with the bottom or top surface of the pallet 30 (pocket 32). Note that since the position of the rear surface of the pallet 30 is difficult to detect, it is preferable that this information is stored in advance in the storage unit 26 as position (coordinate) information or information on the depth dimension of the pallet 30.

[0034] Furthermore, in the above embodiment, the hole estimation line L2 was determined as a line perpendicular to the front detection line L1, based on the positional relationship in which the front surface 31 and the pocket 32 ​​(inner wall) are perpendicular to each other. However, the front surface 31 and the pocket 32 ​​(inner wall) do not necessarily have to be perpendicular to each other; for example, the hole estimation line L2 may be determined as a line that forms a predetermined angle with respect to the front detection line L1.

[0035] Furthermore, in the above embodiment, if the hole estimation line L2 and the fork prediction line L5 intersect, the system notifies that the fork 12 and the pocket 32 ​​will interfere with each other. However, even if the hole estimation line L2 and the fork prediction line L5 do not intersect, if the fork prediction line L5 does not exist between the two hole estimation lines L2 where the pocket 32 ​​should be located, the system may notify that the fork 12 will interfere with the front surface 31 of the pallet 30 (which does not correspond to the pocket 32 ​​opening).

[0036] Furthermore, in the above embodiment, the laser scanner 24 is provided in the center of the left and right sides of the vehicle body 10, but the position of the laser scanner 24 is not particularly limited. However, it is preferable that it be installed at the same height as the forks 12. Also, the measuring means according to the present invention is not limited to a laser scanner, as it is capable of acquiring distance information to the loading platform (front surface).

[0037] Furthermore, the above embodiment was described using the case of picking up a pallet 30 from a pallet stand 41 as an example. However, the loading platform according to the present invention is not limited to pallets, as long as it has holes into which the claws are inserted. Furthermore, the present invention is not limited to the case of unloading pallets from a pallet stand, but is broadly applicable to the case of unloading pallets (loading platforms) (including, for example, flat placement (floor placement) or shelf placement).

[0038] Furthermore, in the above embodiment, the control unit 27 mounted on the forklift 1 performs various calculations. However, a 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.

[0039] Furthermore, in the above embodiment, the forklift 1 was assumed to be an unmanned transport forklift. However, the material handling vehicle according to the present invention includes those that can be operated by a person (including remote operation) and those that can switch between operated by a person and operated unmanned. In addition, the present invention can also be used as an assist function for operated by a person. Furthermore, the cargo handling vehicle according to the present invention is not limited to a forklift, as long as it can hold a load with forks (or something similar) and move, it also includes, for example, an automated guided vehicle (AGV) that operates without a driver. Furthermore, details shown in the above embodiments can be modified as appropriate without departing from the spirit of the invention. [Explanation of symbols]

[0040] 1. Forklift (material handling vehicle) 10 car bodies 12 Fork (toe part) 23 Display unit (notification means) 24. Laser scanner (measurement means) 27 Storage unit (storage means) 27 Control Unit (Detection means, Estimation means, Determination means) 30 pallets (loading platforms) 31 Front 32 pockets (holes) 260 Cargo Pickup Decision Program L1 Front detection line L2 hole estimation line L5 Fork Prediction Line N scan area (measurement area) w1 Width (pocket width)

Claims

1. A measuring means capable of acquiring distance information to a loading platform having a hole in the front, A detection means that determines the front detection line that detected the front surface based on the distance information acquired by the measurement means, An estimation means for determining a hole estimation line by estimating the position of the hole relative to the front surface detection line based on the positional relationship between the front surface and the hole, A determination means for determining interference between the claw portion inserted into the hole and the hole, based on the hole estimation line, Equipped with, The estimation means is, Based on the distance information, the opening end of the hole on the front detection line is determined. The hole estimation line is determined as a line that passes through the open end of the hole and is perpendicular to the front detection line. Cargo acceptance judgment device.

2. The system includes a storage means for pre-storing numerical information about the width of the hole, The estimation means determines the position of the hole estimation line on the front detection line based on the numerical information of the width. The cargo handling determination device according to claim 1.

3. The measuring means is a two-dimensional distance sensor having a planar measuring area along the width direction of the loading platform. A load handling determination device according to claim 1 or claim 2.

4. The system includes a notification means that, when the determination means determines that the claw portion and the hole portion interfere with each other, notifies the determination result that the claw portion and the hole portion interfere. A load handling determination device according to any one of claims 1 to 3.

5. A load picking determination device according to any one of claims 1 to 4, A vehicle body that is capable of driving, The fork, which is a claw portion, is provided on the vehicle body so as to be able to move up and down, and is inserted into the hole to hold the loading platform, A cargo handling vehicle equipped with the following features.

6. A computer for a cargo handling determination device equipped with a measuring means capable of acquiring distance information to a loading platform having a hole in the front, A detection means that determines the front detection line detected on the front surface based on the distance information acquired by the measurement means, Estimation means for determining a hole estimation line by estimating the position of the hole relative to the front detection line, based on the positional relationship between the front surface and the hole. A determination means for determining interference between the claw portion inserted into the hole and the hole, based on the hole estimation line. To make it function as, The estimation means is, Based on the distance information, the opening end of the hole on the front detection line is determined. The hole estimation line is determined as a line that passes through the open end of the hole and is perpendicular to the front detection line. program.

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