Pallet detection device, pallet detection method, and pallet detection program

Abstract

To provide a pallet detection device capable of simply calculating a target point toward which a carrier pallet vehicle should proceed.SOLUTION: A pallet detection device according to one embodiment comprises an optical detector which outputs point group data represented by two-dimensional coordinates including an X-axis extending along the width direction of a carrier pallet vehicle and a Y-axis orthogonal to the X-axis and extending along the longitudinal direction of the carrier pallet vehicle and corresponding to a detection target, and a processing circuit. When it determines that the detection target is a pair of legs of a pallet, the processing circuit is configured so as to calculate a first virtual point on the basis of the first point group data corresponding to one of the pair of legs, calculate a second virtual point on the basis of the second point group data corresponding to the other of the pair of legs, and calculate the midpoint of the line segment connecting the first virtual point and the second virtual point as the target point toward which the carrier pallet vehicle should proceed.SELECTED DRAWING: Figure 3

Description

Technical Field

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[0001] The present disclosure relates to a pallet detection device, a pallet detection method, and a pallet detection program.

Background Art

[0006] A pallet detection device according to one aspect of the present disclosure is a device for detecting a pallet, wherein the pallet comprises a loading section on which heavy objects are loaded, and a plurality of legs supporting the loading section, the plurality of legs including a pair of legs arranged at intervals from each other in the width direction of the pallet at the longitudinal end of the pallet, the device comprising an optical detector that, when mounted on a carrier pallet vehicle, receives light reflected by objects to be detected present around the carrier pallet vehicle and outputs point cloud data corresponding to the objects to be detected, represented by a two-dimensional coordinate system including an X-axis extending along the width direction of the carrier pallet vehicle and a Y-axis perpendicular to the X-axis and extending along the longitudinal direction of the carrier pallet vehicle, and a processing circuit connected to the optical detector, the processing circuit acquires the point cloud data from the optical detector and determines, based on the point cloud data, whether the objects to be detected are the pair of legs or not If it is determined that the object to be detected is the pair of legs, a first virtual point is calculated in the first point cloud data corresponding to one of the pair of legs, where the X-coordinate of the first point closest to the other leg in the X-axis direction is set as the first X-coordinate, and the Y-coordinate of the second point closest to the carrier pallet vehicle in the Y-axis direction is set as the first Y-coordinate. If it is determined that the object to be detected is the pair of legs, a second virtual point is calculated in the second point cloud data corresponding to the other leg, where the X-coordinate of the third point closest to one of the legs in the X-axis direction is set as the second X-coordinate, and the Y-coordinate of the fourth point closest to the carrier pallet vehicle in the Y-axis direction is set as the second Y-coordinate. The midpoint of the line segment connecting the first virtual point and the second virtual point is then calculated as the target point to which the carrier pallet vehicle should be headed.

[0007] A pallet detection method according to one aspect of the present disclosure is a method for detecting a pallet, wherein the pallet comprises a loading section on which heavy objects are loaded, and a plurality of legs supporting the loading section, the plurality of legs including a pair of legs arranged at intervals from each other in the width direction of the pallet at the longitudinal end of the pallet, the method comprising: acquiring point cloud data from an optical detector that, when mounted on the carrier pallet vehicle, receives light reflected by objects to be detected present around the carrier pallet vehicle and outputs point cloud data corresponding to the objects to be detected, which is represented by a two-dimensional coordinate system including an X-axis extending along the width direction of the carrier pallet vehicle and a Y-axis perpendicular to the X-axis and extending along the longitudinal direction of the carrier pallet vehicle; determining, based on the point cloud data, whether the objects to be detected are the pair of legs; and determining whether the objects to be detected are the pair of legs If it is determined that the object is a leg, the first virtual point is calculated by setting the X-coordinate of the first point closest to the other leg in the X-axis direction within the first point cloud data corresponding to one of the pair of legs as the first X-coordinate, and the Y-coordinate of the second point closest to the carrier pallet vehicle in the Y-axis direction within the first point cloud data as the first Y-coordinate; if it is determined that the object to be detected is a leg, the second virtual point is calculated by setting the X-coordinate of the third point closest to one of the leg in the X-axis direction within the second point cloud data corresponding to the other leg as the second X-coordinate, and the Y-coordinate of the fourth point closest to the carrier pallet vehicle in the Y-axis direction within the second point cloud data as the second Y-coordinate; and the midpoint of the line segment connecting the first virtual point and the second virtual point is calculated as the target point to which the carrier pallet vehicle should be headed.

[0008] A palette detection program according to one aspect of this disclosure causes a processor to execute the palette detection method. The program may be stored in a computer-readable storage medium. The storage medium is a non-transitory and tangible medium. The storage medium may be built into or external to a computer. The computer includes, for example, a personal computer, or a server. The storage medium includes RAM, ROM, EEPROM, and external storage devices. The storage medium may be, for example, a hard disk, flash memory, or optical disc. The program stored in the storage medium may be executed on a computer to which the storage medium is directly connected, or on a computer connected to the storage medium via a communication network. The communication network includes, for example, a LAN (Local Area Network) or the Internet.

[0009] According to one aspect of this disclosure, a pallet detection device can easily calculate the target point to which a carrier pallet vehicle should head. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic diagram of a carrier pallet vehicle and pallet equipped with a pallet detection device according to an embodiment. [Figure 2] Figure 2 is a block diagram of the control system for a carrier pallet vehicle. [Figure 3] Figure 3 is a flowchart of the processing performed by the processing circuit of the pallet detection device according to the embodiment. [Figure 4] Figure 4 is a schematic diagram showing point cloud data, a first virtual point, a second virtual point, and a midpoint as the target point. [Figure 5] Figure 5 is a schematic diagram showing a carrier pallet truck traveling towards a target point. [Modes for carrying out the invention]

[0011] Embodiments will be described below with reference to the drawings.

[0012] Figure 1 is a schematic diagram of a carrier pallet truck 2 and a pallet 3 equipped with a pallet detection device 1 according to an embodiment. The pallet detection device 1 detects the pallet 3 arranged around the carrier pallet truck 2. The pallet detection device 1 comprises a first computer 11 and at least one optical detector 18. Details of the first computer 11 and at least one optical detector 18 will be described later.

[0013] The carrier pallet truck 2 comprises a loading platform 20 and a plurality of tires 21 supporting the loading platform 20. The loading platform 20 is capable of carrying pallets 3. The plurality of tires 21 include a plurality of pairs of tires 21. Each pair of tires 21 is coupled to a separate axle 22. A hydraulic lifting cylinder 23 is individually provided between the loading platform 20 and each axle 22. The loading platform 20 is raised and lowered by the extension and retraction of each lifting cylinder 23.

[0014] Pallet 3 comprises a loading section 40 on which heavy objects are loaded, and a plurality of legs 41 supporting the loading section 40. Pallet 3 is defined by a longitudinal direction, a width direction, and a height direction that are perpendicular to each other. The height direction is perpendicular to the ground. The number of the plurality of legs 41 is, for example, 20. In this embodiment, each of the plurality of legs 41 is an H-beam. Each leg 41 extends along the height direction such that its cross-section perpendicular to the height direction is H-shaped. Each leg 41 is fixed to the loading section 40. The plurality of legs 41 includes a plurality of pairs of legs 41. Each pair of legs 41 is positioned at the same location as each other in the longitudinal direction of pallet 3 and spaced apart from each other in the width direction of pallet 3. Each pair of legs 41 is spaced apart in the longitudinal direction of pallet 3. The plurality of pairs of legs 41 includes a pair of legs 41 positioned at the longitudinal end of pallet 3.

[0015] Figure 2 is a block diagram of the control system of the carrier pallet vehicle 2. In Figure 2, an example is shown in which the pallet detection device 1 is configured by a first computer 11 and the automatic driving control device 30 is configured by a second computer 31 different from the first computer 11, but the pallet detection device 1 and the automatic driving control device 30 may be configured by a single computer. The carrier pallet vehicle 2 further comprises the automatic driving control device 30, a satellite positioning receiver 24, an antenna 25, an engine 26, a switching valve 27, a braking device 28, and a steering device 29.

[0016] The automatic driving control device 30 receives position information via the satellite positioning receiver 24 through the antenna 25. The satellite positioning receiver 24 and the antenna 25 constitute part of the satellite positioning system. The satellite positioning system includes, for example, RTK-GNSS or the Quasi-Zenith Satellite System. The automatic driving control device 30 adjusts the speed, acceleration, and deceleration of the carrier pallet vehicle 2 by controlling the engine 26. The driving energy of the engine 26 is used to rotate the tires 21. The driving energy of the engine 26 is also used to drive a hydraulic pump connected to the lifting cylinder 23 via a switching valve 27. The automatic driving control device 30 raises and lowers the cargo bed 20 by extending and retracting the lifting cylinder 23 by controlling the switching valve 27. The automatic driving control device 30 brakes the carrier pallet vehicle 2 by controlling the braking device 28. The automatic driving control device 30 adjusts the steering angle of the carrier pallet vehicle 2 by controlling the steering device 29.

[0017] The automatic driving control device 30 may, depending on the relative positional relationship between the carrier pallet vehicle 2 and the pallet 3, drive the carrier pallet vehicle 2 with one end in the longitudinal direction of the carrier pallet vehicle 2 as the front end, or drive the carrier pallet vehicle 2 with the other end in the longitudinal direction of the carrier pallet vehicle 2 as the front end.

[0018] The automatic driving control device 30 includes a second computer 31. The second computer 31 is communicably connected to the satellite positioning receiver 24, the engine 26, the braking device 28, and the steering device 29 respectively by an electric cable or a wireless communication device. The second computer 31 includes a processor 32, a system memory 33, a storage memory 34, and interfaces (I / F) 35 to 37. The processor 32 is, for example, a micro control unit (MPU) or a central processing unit (CPU), etc. The processor 32 may be distributed among a plurality of processors. The system memory 33 is, for example, a RAM. The storage memory 34 is an example of a computer-readable medium and is a non-transitory and tangible medium. The storage memory 34 may include a ROM, an EEPROM, a hard disk, a flash memory, an optical disk, or a combination thereof.

[0019] The storage memory 34 stores an automatic driving control program PR2. The processor 32 reads the automatic driving control program PR2 from the storage memory 34 into the system memory 33 and executes it. The configuration in which the processor 32 executes the automatic driving control program PR2 read into the system memory 33 is an example of the processing circuit of the automatic driving control device 30. The second computer 31 may be an example of a processing circuit. A part or all of the automatic driving control program PR2 may be executed by the processing circuit of a server connected to the automatic driving control device 30 via a network.

[0020] The position information received by the satellite positioning receiver 24 via the antenna 25 is input to the interface 35. The interface 36 outputs the drive commands generated by the processor 32 according to the automatic driving control program PR2 to the engine 26, the braking device 28, and the steering device 29. The interface 37 is an I / O interface to which data such as a target point TP (to be described later) output from the interface 16 of the pallet detection device 1 is input.

[0021] The pallet detection device 1 includes a first computer 11 and at least one optical detector 18. In the present embodiment, the at least one optical detector 18 includes a pair of optical detectors 18. The first computer 11 is communicably connected to each of the pair of optical detectors 18 by an electric cable or a wireless communication device. The pair of optical detectors 18 each have the same structure. The first computer 11 includes a processor 12, a system memory 13, a storage memory 14, and interfaces 15, 16. The processor 12 is, for example, a micro control unit (MPU) or a central processing unit (CPU). The processor 12 may be distributed among a plurality of processors. The system memory 13 is, for example, a RAM. The storage memory 14 is an example of a computer-readable medium and is a non-transitory and tangible medium. The storage memory 14 may include a ROM, an EEPROM, a hard disk, a flash memory, an optical disk, or a combination thereof.

[0022] The storage memory 14 stores a pallet detection program PR1. The processor 12 reads the pallet detection program PR1 from the storage memory 14 into the system memory 13 and executes it. The configuration in which the processor 12 executes the pallet detection program PR1 read into the system memory 13 is an example of the processing circuit of the pallet detection device 1. The first computer 11 may be an example of the processing circuit. A part or all of the pallet detection program PR1 may be executed by the processing circuit of a server connected to the pallet detection device 1 via a network.

[0023] Interface 15 receives point cloud data PG corresponding to the object to be detected from each of the pair of optical detectors 18. Interface 16 is an I / O interface that outputs data such as the target point TP, which will be described later, calculated based on commands generated by the processor 12 according to the pallet detection program PR1, to the interface 37 of the automatic driving control device 30. Interface 16 of the first computer 11 and interface 37 of the second computer 31 are connected to each other so as to be able to communicate data. Interface 16 of the first computer 11 and interface 37 of the second computer 31 are connected so as to be able to communicate by an electrical cable or a wireless communication device.

[0024] Each of the pair of optical detectors 18, when mounted on the carrier pallet vehicle 2, receives light reflected by objects to be detected in the vicinity of the carrier pallet vehicle 2. One of the pair of optical detectors 18 is mounted on one end 2a in the longitudinal direction of the carrier pallet vehicle 2 and on the central part 2b in the width direction of the carrier pallet vehicle 2. The other of the pair of optical detectors 18 is mounted on the other end 2c in the longitudinal direction of the carrier pallet vehicle 2 and on the central part 2d in the width direction of the carrier pallet vehicle 2. For example, each of the pair of optical detectors 18 can be a 2D-LiDAR (Light Detection And Ranging) capable of measuring distance by scanning laser light horizontally.

[0025] Figure 3 is a flowchart of the processing performed by the processing circuit of the pallet detection device 1 according to the embodiment. Hereinafter, the procedure for detecting pallet 3 by the pallet detection device 1 will be explained following the flow shown in Figure 3, with reference to Figures 1 and 2 as appropriate and mainly to Figure 4. The processor 12 executes the pallet detection program PR1 read into the system memory 13. The processor 12 may, for example, operate only the optical detector 18 of the pair of optical detectors 18 that is closer to the pallet 3 to be transported, according to the position information of the carrier pallet vehicle 2 and the position information of pallet 3.

[0026] Figure 4 is a schematic diagram showing point cloud data PG, a first virtual point VP1, a second virtual point VP2, and a midpoint CP as the target point TP. First, the processor 12 acquires point cloud data PG corresponding to the object to be detected from one optical detector 18 (step S1). The point cloud data PG is represented by a two-dimensional coordinate system including an X-axis extending along the width direction of the carrier pallet vehicle 2 and a Y-axis perpendicular to the X-axis and extending along the longitudinal direction of the carrier pallet vehicle 2. In this embodiment, the origin of the two-dimensional coordinate system is set to the placement point of the optical detector 18.

[0027] The processor 12 may start acquiring point cloud data PG from the moment the carrier pallet vehicle 2 is positioned within a predetermined range from the pallet 3 to be transported by autonomous driving. The processor 12 may also start acquiring point cloud data PG before the carrier pallet vehicle 2 is positioned within a predetermined range from the pallet 3. The processor 12 may acquire point cloud data PG at a period of, for example, 20 mm seconds.

[0028] Next, the processor 12 determines whether the object to be detected is a pair of legs 41 of the pallet 3 based on the point cloud data PG acquired in step S1 (step S2). For example, the storage memory 14 stores data indicating the shape, dimensions, and spacing of each of the pair of legs 41 of the pallet 3. The processor 12 determines whether the object to be detected indicated by the point cloud data PG is a pair of legs 41 of the pallet 3 by performing pattern matching, for example, by comparing the object to be detected indicated by the point cloud data PG with reference data stored in the storage memory 14. The processor 12 may perform a median filter on the point cloud data PG acquired in step S1 to remove noise before performing step S2.

[0029] Next, if the processor 12 determines in step S2 that the object to be detected is a pair of legs 41 of the pallet 3, it calculates a first virtual point VP1 (step S3). The first virtual point VP1 is a virtual point in the first point cloud data PG1, which corresponds to one of the pair of legs 41, where the first X coordinate is X1max of the first point P1 that is closest to the other leg 41 in the X-axis direction, and the first Y coordinate is Y1min of the second point P2 that is closest to the carrier pallet vehicle 2 in the Y-axis direction.

[0030] Next, if the processor 12 determines in step S2 that the object to be detected is a pair of legs 41 of the pallet 3, it calculates a second virtual point VP2 (step S4). The second virtual point VP2 is a virtual point in the second point cloud data PG2, which corresponds to the other leg of the pair of legs 41, where the second X coordinate is the X2min of the third point P3 that is closest to one of the pair of legs 41 in the X-axis direction, and the second Y coordinate is the Y2min of the fourth point P4 that is closest to the carrier pallet vehicle 2 in the Y-axis direction.

[0031] Next, the processor 12 calculates the midpoint CP of the line segment L connecting the first virtual point VP1 calculated in step S3 and the second virtual point VP2 calculated in step S4, as the target point TP that the carrier pallet vehicle 2 should head to (step S5). In step S5, the processor 12 calculates the X coordinate of the midpoint CP by calculating the relation (X1max+X2min) / 2 and the Y coordinate of the midpoint CP by calculating the relation (Y1min+Y2min) / 2.

[0032] Next, the processor 12 calculates the angle α of the Y-axis with respect to the line segment L (step S6).

[0033] Finally, the processor 12 outputs the X and Y coordinates of the midpoint CP, which is the target point TP calculated in step S5, and the angle α calculated in step S6, to the automatic driving control device 30 (step S7). In step S7, the processor 12 may further output the point cloud data PG acquired in step S1 to the automatic driving control device 30.

[0034] Figure 5 is a schematic diagram showing the carrier pallet truck 2 traveling toward the target point TP. As shown in Figure 5, the automatic driving control device 30 automatically drives the carrier pallet truck 2 toward the target point TP based on the X and Y coordinates of the target point TP and the angle α received from the pallet detection device 1, such that the Y axis is perpendicular to the line segment L and the center of the carrier pallet truck 2 in the width direction is toward the target point TP. With the lifting cylinder 23 retracted and the loading platform 20 lowered, the automatic driving control device 30 automatically drives the carrier pallet truck 2 toward the target point TP.

[0035] When the carrier pallet vehicle 2 approaches the target point TP and the pair of legs 41 move out of the detection range of the optical detector 18, the optical detector 18 can detect another pair of legs 41 adjacent to the pair of legs 41 in the longitudinal direction of the pallet 3 and output the target point TP and angle α for the other pair of legs 41 to the automatic driving control device 30 using the same procedure as in steps S1 to S7. The automatic driving control device 30 can then drive the carrier pallet vehicle 2 automatically toward the target point TP for the other pair of legs 41. By repeating the above procedure, the carrier pallet vehicle 2 can properly enter below the pallet 3 while avoiding collision with multiple legs 41 of the pallet 3.

[0036] Next, the automatic driving control device 30 extends the lifting cylinder 23 to raise the loading platform 20, thereby placing the pallet 3 on the loading platform 20. Next, the automatic driving control device 30 drives the carrier pallet truck 2 to the location where the pallet 3 should be transported. Finally, the automatic driving control device 30 retracts the lifting cylinder 23 at the destination to lower the loading platform 20, thereby placing the pallet 3 at the destination.

[0037] According to the configuration of this embodiment, the target point TP to which the carrier pallet vehicle 2 should head is calculated by calculating a first virtual point VP1 based on first point cloud data PG1 corresponding to one of the pair of legs 41 of the pallet 3, calculating a second virtual point VP2 based on second point cloud data PG2 corresponding to the other of the pair of legs 41 of the pallet 3, and calculating the midpoint CP of the line segment L connecting the first virtual point VP1 and the second virtual point VP2. Therefore, the pallet detection device 1 can easily calculate the target point TP with relatively simple calculations. Furthermore, the pallet detection device 1 can calculate the target point TP without depending on the distance between one of the pair of legs 41 and the other of the pair of legs 41. Furthermore, the pallet detection device 1 can calculate the target point TP without depending on the shape of each of the pair of legs 41.

[0038] The angle α of the Y-axis with respect to the line segment L connecting the first virtual point VP1 and the second virtual point VP2 is calculated, so the automatic driving control device 30 can drive the carrier pallet vehicle 2 automatically so that the Y-axis is perpendicular to the line segment L based on the angle α. This prevents the carrier pallet vehicle 2 from tilting relative to the pallet 3 when it reaches the target point TP, as viewed from above. Therefore, the carrier pallet vehicle 2 can properly enter under the pallet 3. The automatic driving control device 30 may also perform an emergency stop on the carrier pallet vehicle 2 if it determines that the angle α of the Y-axis with respect to the line segment L is greater than a threshold. This prevents the carrier pallet vehicle 2 from colliding with the multiple legs 41 of the pallet 3.

[0039] Since the optical detector 18 is mounted at the longitudinal end of the carrier pallet vehicle 2 and in the center of the width direction of the carrier pallet vehicle 2, and the origin of the two-dimensional coordinate system is set to the position of the optical detector 18, the pallet detection device 1 can easily calculate the target point TP that the carrier pallet vehicle 2 should head towards.

[0040] Since the optical detector 18 includes a 2D-LiDAR, the pallet detection device 1 can detect point cloud data PG corresponding to the pair of legs 41 of the pallet 3 with a relatively inexpensive configuration.

[0041] In this embodiment, the case in which the optical detector 18 is mounted at the longitudinal end of the carrier pallet vehicle 2 and in the center in the width direction of the carrier pallet vehicle 2 has been described. The mounting position of the optical detector 18 is not limited to the position described in this embodiment, as long as it can properly detect objects present around the carrier pallet vehicle 2. For example, the optical detector 18 may be mounted at the longitudinal end of the carrier pallet vehicle 2 and in the width direction of the carrier pallet vehicle 2, or it may be mounted on other parts of the carrier pallet vehicle 2. For example, the storage memory 14 may store data indicating the relative position of the optical detector 18 with respect to the longitudinal end of the carrier pallet vehicle 2 and in the center in the width direction of the carrier pallet vehicle 2. By using data indicating the relative position, the origin of the two-dimensional coordinate system may be set at the longitudinal end of the carrier pallet vehicle 2 and in the center in the width direction of the carrier pallet vehicle 2, rather than at the placement point of the optical detector 18, based on the data indicating the relative position.

[0042] In this embodiment, the case was described in which the pallet detection device 1 calculates the angle α of the Y-axis with respect to the line segment L, and the automatic driving control device 30 drives the carrier pallet vehicle 2 by automatic driving so that the Y-axis is perpendicular to the line segment L. However, the pallet detection device 1 may calculate the angle of the X-axis with respect to the line segment L, and the automatic driving control device 30 may drive the carrier pallet vehicle 2 by automatic driving so that the X-axis is parallel to the line segment L.

[0043] In this embodiment, the case in which the optical detector 18 includes a 2D-LiDAR has been described. However, the optical detector 18 may include an LRF (Laser Range Finder) instead of a 2D-LiDAR, as long as it can output point cloud data corresponding to the objects to be detected that are present around the carrier pallet vehicle 2.

[0044] In this embodiment, the case where step S3, which calculates the first virtual point VP1, is performed based on the flowchart in Figure 3, followed by step S4, which calculates the second virtual point VP2, has been described. However, step S3 may be performed after step S4, or steps S3 and S4 may be performed in parallel.

[0045] In this embodiment, the case in which the pallet detection device 1 is equipped with a pair of optical detectors 18 has been described. However, one of the pair of optical detectors 18 may be omitted.

[0046] The functions of the elements disclosed herein can be performed using circuits or processing circuits, including general-purpose processors, dedicated processors, integrated circuits, ASICs (Application Specific Integrated Circuits), conventional circuits, and / or combinations thereof, configured or programmed to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuits. In this disclosure, a circuit, unit, or means is hardware that performs the enumerated functions, or hardware programmed to perform the enumerated functions. The hardware may be hardware disclosed herein, or other known hardware that is programmed or configured to perform the enumerated functions. If the hardware is a processor, which is considered a type of circuit, then the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware and / or the processor.

[0047] Each of the following embodiments is a disclosure of a preferred embodiment. [Aspect 1] A device for detecting pallets, The pallet comprises a loading section on which heavy objects are loaded, and a plurality of legs supporting the loading section, wherein the plurality of legs include a pair of legs that are spaced apart from each other in the width direction of the pallet at the longitudinal end of the pallet. The aforementioned device is An optical detector, when mounted on a carrier pallet vehicle, receives light reflected by objects to be detected surrounding the carrier pallet vehicle, and outputs point cloud data corresponding to the detected objects, represented by a two-dimensional coordinate system including an X-axis extending along the width direction of the carrier pallet vehicle and a Y-axis perpendicular to the X-axis and extending along the longitudinal direction of the carrier pallet vehicle. The optical detector is connected to a processing circuit, The aforementioned processing circuit is The point cloud data is acquired from the optical detector. Based on the point cloud data, it is determined whether or not the object to be detected is the pair of legs. When it is determined that the object to be detected is the pair of legs, a first virtual point is calculated in the first point cloud data corresponding to one of the pair of legs, where the X-coordinate of the first point closest to the other leg in the X-axis direction is set as the first X-coordinate, and the Y-coordinate of the second point closest to the carrier pallet vehicle in the Y-axis direction is set as the first Y-coordinate. When it is determined that the object to be detected is the pair of legs, a second virtual point is calculated in the second point cloud data corresponding to the other leg of the pair, where the X-coordinate of the third point closest to one of the legs in the X-axis direction is set as the second X-coordinate, and the Y-coordinate of the fourth point closest to the carrier pallet vehicle in the Y-axis direction is set as the second Y-coordinate. A pallet detection device configured to calculate the midpoint of the line segment connecting the first virtual point and the second virtual point as the target point to which the carrier pallet vehicle should head. [Aspect 2] The pallet detection device according to embodiment 1, wherein the processing circuit is configured to calculate the angle of the X-axis or the Y-axis with respect to the line segment. [Aspect 3] The optical detector is mounted at the longitudinal end of the carrier pallet vehicle and in the center in the width direction of the carrier pallet vehicle. The pallet detection device according to embodiment 1 or 2, wherein the origin of the two-dimensional coordinate system is set to the placement point of the optical detector. [Aspect 4] The pallet detection device according to any one of embodiments 1 to 3, wherein the optical detector includes a 2D-LiDAR (Light Detection And Ranging) capable of measuring distance by scanning laser light horizontally. [Aspect 5] A method for detecting a palette, The pallet comprises a loading section on which heavy objects are loaded, and a plurality of legs supporting the loading section, wherein the plurality of legs include a pair of legs that are spaced apart from each other in the width direction of the pallet at the longitudinal end of the pallet. The aforementioned method, In the state in which it is attached to the carrier pallet vehicle, light reflected by objects to be detected present around the carrier pallet vehicle is input, and point cloud data is acquired from an optical detector that outputs point cloud data corresponding to the objects to be detected, which is represented by a two-dimensional coordinate system including an X-axis extending along the width direction of the carrier pallet vehicle and a Y-axis perpendicular to the X-axis and extending along the longitudinal direction of the carrier pallet vehicle. Based on the point cloud data, it is determined whether or not the object to be detected is the pair of legs. When it is determined that the object to be detected is the pair of legs, a first virtual point is calculated in which the X-coordinate of the first point in the first point cloud data corresponding to one of the pair of legs is set as the first X-coordinate, and the Y-coordinate of the second point in the first point cloud data that is closest to the carrier pallet vehicle in the Y-axis direction is set as the first Y-coordinate. When it is determined that the object to be detected is the pair of legs, a second virtual point is calculated in the second point cloud data corresponding to the other leg of the pair, where the X-coordinate of the third point closest to one of the legs in the X-axis direction is set as the second X-coordinate, and the Y-coordinate of the fourth point closest to the carrier pallet vehicle in the Y-axis direction is set as the second Y-coordinate. A pallet detection method comprising: calculating the midpoint of the line segment connecting the first virtual point and the second virtual point as the target point to which the carrier pallet vehicle should head. [Aspect 6] A palette detection program that causes a processor to execute the palette detection method described in Embodiment 5. [Explanation of Symbols]

[0048] 1. Pallet detection device 2 Carrier pallet trucks 3 Palettes 12 processors 18 Optical detectors 40 Loading section 41 Legs PG point cloud data PG1 First point cloud data PG2 Second Point Cloud Data P1~4 1st~4 points TP target point CP midpoint VP1,2 First and second virtual points L-shaped line segment α angle PR1 Palette Detection Program

Claims

1. A device for detecting pallets, The pallet comprises a loading section on which heavy objects are loaded, and a plurality of legs supporting the loading section, wherein the plurality of legs include a pair of legs that are spaced apart from each other in the width direction of the pallet at the longitudinal end of the pallet. The aforementioned device is An optical detector, when mounted on a carrier pallet vehicle, receives light reflected by objects to be detected surrounding the carrier pallet vehicle, and outputs point cloud data corresponding to the detected objects, represented by a two-dimensional coordinate system including an X-axis extending along the width direction of the carrier pallet vehicle and a Y-axis perpendicular to the X-axis and extending along the longitudinal direction of the carrier pallet vehicle. The optical detector is connected to a processing circuit, The aforementioned processing circuit is The point cloud data is acquired from the optical detector. Based on the point cloud data, it is determined whether or not the object to be detected is the pair of legs. When it is determined that the object to be detected is the pair of legs, a first virtual point is calculated in which the X-coordinate of the first point in the first point cloud data corresponding to one of the pair of legs is set as the first X-coordinate, and the Y-coordinate of the second point in the first point cloud data that is closest to the carrier pallet vehicle in the Y-axis direction is set as the first Y-coordinate. When it is determined that the object to be detected is the pair of legs, a second virtual point is calculated in the second point cloud data corresponding to the other leg of the pair, where the X-coordinate of the third point closest to one of the legs in the X-axis direction is set as the second X-coordinate, and the Y-coordinate of the fourth point closest to the carrier pallet vehicle in the Y-axis direction is set as the second Y-coordinate. A pallet detection device configured to calculate the midpoint of the line segment connecting the first virtual point and the second virtual point as the target point to which the carrier pallet vehicle should head.

2. The pallet detection device according to claim 1, wherein the processing circuit is configured to calculate the angle of the X-axis or the Y-axis with respect to the line segment.

3. The optical detector is mounted at the longitudinal end of the carrier pallet vehicle and in the center in the width direction of the carrier pallet vehicle. The pallet detection device according to claim 1 or 2, wherein the origin of the two-dimensional coordinate system is set to the placement point of the optical detector.

4. The pallet detection device according to claim 1 or 2, wherein the optical detector includes a 2D-LiDAR (Light Detection and Ranging) capable of measuring distance by scanning laser light horizontally.

5. A method for detecting a palette, The pallet comprises a loading section on which heavy objects are loaded, and a plurality of legs supporting the loading section, wherein the plurality of legs include a pair of legs that are spaced apart from each other in the width direction of the pallet at the longitudinal end of the pallet. The aforementioned method, In a state mounted on a carrier pallet vehicle, light reflected by objects to be detected present around the carrier pallet vehicle is input, and point cloud data is acquired from an optical detector that outputs point cloud data corresponding to the detected objects, which is represented by a two-dimensional coordinate system including an X-axis extending along the width direction of the carrier pallet vehicle and a Y-axis perpendicular to the X-axis and extending along the longitudinal direction of the carrier pallet vehicle. Based on the point cloud data, it is determined whether or not the object to be detected is the pair of legs. When it is determined that the object to be detected is the pair of legs, a first virtual point is calculated in which the X-coordinate of the first point in the first point cloud data corresponding to one of the pair of legs is set as the first X-coordinate, and the Y-coordinate of the second point in the first point cloud data that is closest to the carrier pallet vehicle in the Y-axis direction is set as the first Y-coordinate. When it is determined that the object to be detected is the pair of legs, a second virtual point is calculated in the second point cloud data corresponding to the other leg of the pair, where the X-coordinate of the third point closest to one of the legs in the X-axis direction is set as the second X-coordinate, and the Y-coordinate of the fourth point closest to the carrier pallet vehicle in the Y-axis direction is set as the second Y-coordinate. A pallet detection method comprising: calculating the midpoint of the line segment connecting the first virtual point and the second virtual point as the target point to which the carrier pallet vehicle should head.

6. A palette detection program that causes a processor to execute the palette detection method described in claim 5.

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