Loading and unloading control device

Abstract

To provide a loading and unloading control device that is able to reduce a total loading and unloading time.SOLUTION: A loading and unloading control device 20 includes: an approach control unit that exerts control to cause a forklift 1 to approach a loading position P; an approach determination unit 36 that determines whether the approach of the forklift 1 has succeeded; a placing control unit 41 that exerts control to place a pallet 11 at a loading place 18a when the approach determination unit determines that the approach of the forklift 1 has succeeded; a re-approach control unit that exerts control to cause the forklift 1 to re-approach the loading position when it is determined that the approach of the forklift 1 has failed; a loading possibility determination unit 32 that determines whether there is a possibility that the loading of the pallet 11 at the loading place 18a will be successful; and an anomaly stop control unit 42 that exerts control to stop traveling of the forklift 1 due to an anomaly when it is determined that there is no possibility that the loading of the pallet 11 will be successful.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a cargo handling control device. [Background technology]

[0002] Known conventional cargo handling control devices include, for example, the technology described in Patent Document 1. The cargo handling control device described in Patent Document 1 detects the position and posture of the object to be transported using a sensor when a forklift moves along a first path across an installation area where an object to be transported, which is a pallet loaded with cargo, is set, and based on the position and posture of the object to be transported, sets a second path to a target position where the object to be transported has a predetermined position and posture, and moves the forklift along the second path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-70559 Summary of the Invention [Problem to be solved by the invention]

[0004] When a forklift is automatically operated to place a pallet, if an estimation error in the forklift's own position or a guidance error occurs, the forklift may fail to approach the placement location, causing the forklift's position to deviate from the placement location, making it impossible to place the pallet. In this case, the likelihood of successfully placing the pallet increases if the forklift re-approaches the placement location. However, for example, if the loading platform on which the pallet is to be placed is tilted, the forklift may not be able to place the pallet even if it successfully approaches the placement location. In this case, even if the forklift approaches the placement location multiple times, the likelihood of successfully placing the pallet is low, resulting in a longer total handling time.

[0005] An object of the present invention is to provide a cargo handling control device that can shorten the total cargo handling time. [Means for solving the problem]

[0006] (1) One aspect of the present invention is a cargo handling control device that moves a forklift holding a pallet with its forks from a start position toward a loading position to load the pallet, the cargo handling control device comprising: a loading position detection unit that detects the loading position; a position and attitude calculation unit that calculates the position and attitude of the loading position relative to the forklift based on detection data from the loading position detection unit; an approach control unit that controls the forklift to approach a loading position in front of the loading position based on the position and attitude of the loading position relative to the forklift calculated by the position and attitude calculation unit when the forklift is at the start position; an approach determination unit that determines whether the forklift has successfully approached the loading position based on the position and attitude of the loading position relative to the forklift calculated by the position and attitude calculation unit when the forklift reaches the loading position; The system includes a loading control unit that controls the forklift to load the pallet at the loading location when it is determined that the forklift's approach to the loading location has been successful; a re-approach control unit that controls the forklift to load the pallet again to the loading location when it is determined by the approach determination unit that the forklift's approach to the loading location has failed, based on the position and attitude of the loading location relative to the forklift calculated by the position and attitude calculation unit; a loading possibility determination unit that determines whether there is a possibility that the pallet will be successfully loaded at the loading location based on the position and attitude of the loading location relative to the forklift calculated by the position and attitude calculation unit; and an abnormal stop control unit that controls the forklift to abnormally stop traveling of the forklift when it is determined by the loading possibility determination unit that there is no possibility that the pallet will be successfully loaded at the loading location.

[0007] In such a cargo handling control device, a placement location is detected at a start position, and the position and orientation of the placement location relative to the forklift are calculated. Then, based on the position and orientation of the placement location relative to the forklift, the forklift is controlled to approach a placement location just before the placement location. When the forklift reaches the placement location, the placement location is detected again, and the position and orientation of the placement location relative to the forklift are calculated. Then, based on the position and orientation of the placement location relative to the forklift, it is determined whether the forklift's approach to the placement location was successful. If it is determined that the forklift's approach to the placement location was successful, the forklift is controlled to place the pallet at the placement location. If it is determined that the forklift's approach to the placement location was unsuccessful, the forklift is controlled to approach the placement location again based on the position and orientation of the placement location relative to the forklift. Furthermore, based on the position and orientation of the placement location relative to the forklift, it is determined whether there is a possibility that the pallet will be successfully placed at the placement location. If it is determined that there is no possibility of successfully placing the pallet at the loading location, the forklift is controlled to make an abnormal stop. By making the forklift come to an abnormal stop when it is determined that there is no possibility of successfully placing the pallet at the loading location, it is possible to avoid a wasteful approach by the forklift, thereby reducing the total loading and unloading time.

[0008] (2) In (1) above, the loading possibility determination unit determines whether there is a possibility of successfully loading the pallet at the loading location based on the position and attitude of the loading location relative to the forklift calculated by the position and attitude calculation unit when the forklift is at the starting position, and the approach control unit, when it determines that there is a possibility of successfully loading the pallet at the loading location, may control the forklift to approach the loading location based on the position and attitude of the loading location relative to the forklift calculated by the position and attitude calculation unit when the forklift is at the starting position.

[0009] In this configuration, when the forklift is at the starting position, it is determined whether there is a possibility that the pallet will be successfully placed at the placement location. If it is determined that there is no possibility that the pallet will be successfully placed at the placement location, the forklift does not need to approach from the starting position. This further reduces the total loading and unloading time.

[0010] (3) In (1) or (2) above, the loading possibility determination unit may determine that there is a possibility that the pallet will be successfully loaded at the loading location when the pitch angle of the forklift relative to the loading location is equal to or less than a predetermined pitch angle threshold and the roll angle of the forklift relative to the loading location is equal to or less than a predetermined roll angle threshold, and may determine that there is no possibility that the pallet will be successfully loaded at the loading location when the pitch angle of the forklift relative to the loading location is greater than the pitch angle threshold or when the roll angle of the forklift relative to the loading location is greater than the roll angle threshold.

[0011] With this configuration, if the loading area is tilted more than necessary, causing the pitch angle of the forklift relative to the loading area to exceed the pitch angle threshold, or the roll angle of the forklift relative to the loading area to exceed the roll angle threshold, it is possible to avoid performing a wasteful approach by the forklift.

[0012] (4) In any of (1) to (3) above, the forklift has a side shift cylinder that moves the forks in the left and right directions of the forklift, and the approach determination unit may determine that the forklift has successfully approached the loading location when the amount of lateral deviation of the forklift from the loading location is equal to or less than a predetermined specified amount and the yaw angle of the forklift from the loading location is equal to or less than a predetermined yaw angle threshold, and may determine that the forklift has failed to approach the loading location when the amount of lateral deviation of the forklift from the loading location is greater than the specified amount or the yaw angle of the forklift from the loading location is greater than the yaw angle threshold.

[0013] In such a configuration, if the forklift's lateral deviation from the loading location exceeds a specified amount due to, for example, a self-position estimation error or a guidance error of the forklift, or if the forklift's yaw angle relative to the loading location exceeds a yaw angle threshold, the forklift is made to approach the loading location again, thereby increasing the probability that the forklift will reach an appropriate loading location just before the loading location.

[0014] (5) In any of (1) to (4) above, the cargo handling control device further includes a re-approach determination unit that determines whether the forklift has successfully re-approached the loading position based on the position and attitude of the loading location relative to the forklift calculated by the position and attitude calculation unit when the forklift reaches the loading position again, and if the re-approach determination unit determines that the forklift has failed to re-approach the loading position, the re-approach control unit controls the forklift to re-approach the loading position based on the position and attitude of the loading location relative to the forklift calculated by the position and attitude calculation unit, and if the re-approach determination unit determines that the forklift has successfully re-approached the loading position, the loading control unit may control the forklift to deposit the pallet at the loading location.

[0015] In this configuration, if the forklift fails to re-approach the loading location, the forklift can be made to re-approach the loading location, increasing the probability that the forklift will reach an appropriate loading location just before the loading location.

[0016] (6) In (5) above, the cargo handling control device may further include a count determination unit that determines whether the number of times the forklift has re-approached the loading location has reached a predetermined upper limit when the re-approach determination unit determines that the forklift has failed to re-approach the loading location, and the abnormal stop control unit may control the forklift to abnormally stop its travel when the loading possibility determination unit determines that there is no possibility of successful loading of the pallet at the loading location, or when the count determination unit determines that the number of times the forklift has re-approached the loading location has reached the upper limit.

[0017] In this configuration, when the number of times the forklift attempts to approach the loading position reaches the upper limit, the forklift stops, eliminating the need for unnecessary re-approaches, further reducing the total loading time.

[0018] (7) In any of (1) to (6) above, if the re-approach control unit determines that the forklift's approach to the loading position has failed, the re-approach control unit may control the forklift to temporarily retreat to the loading position and then re-approach the loading position based on the position and attitude of the loading point relative to the forklift calculated by the position and attitude calculation unit when the forklift is at the loading position.

[0019] In this configuration, if a forklift fails to approach a loading position, the loading location is detected at the loading position. Then, based on the position and posture of the loading location relative to the forklift, the forklift is controlled to temporarily retreat from the loading location and then re-approach the loading location. This ensures sufficient accuracy in the position of the loading location relative to the forklift while the forklift re-approaches the loading location. This increases the probability that the forklift will reach an appropriate loading location just before the loading location.

[0020] (8) In any of (1) to (6) above, if the re-approach control unit determines that the forklift's approach to the loading position has failed, it may control the forklift to temporarily retreat to the loading position, and then control the forklift to re-approach the loading position based on the position and attitude of the loading location relative to the forklift calculated by the position and attitude calculation unit.

[0021] In this configuration, if a forklift fails to approach a loading location, the forklift is first controlled to temporarily retreat from the loading location. Then, based on the position and posture of the loading location relative to the forklift, the forklift is controlled to re-approach the loading location. This shortens the travel distance of the forklift after a travel path for the forklift to re-approach the loading location is set. This further increases the probability that the forklift will reach an appropriate loading location just before the loading location.

[0022] (9) In (8) above, the re-approach control unit may control the forklift to retreat to the starting position relative to the loading position, and then control the forklift to re-approach the loading position based on the position and posture of the loading location relative to the forklift calculated by the position and posture calculation unit when the forklift is at the starting position.

[0023] In this configuration, if the forklift fails to approach the loading position, the process can be simplified by temporarily retreating the forklift to the start position, which is known in advance as position information.

[0024] (10) In any of the above (1) to (9), the load placement location detection unit may detect the load placement location while the forklift is facing forward toward the load placement location.

[0025] In this configuration, the load location is detected with the forklift facing forward when the forklift is in either the start position or the load location, which minimizes the number of sensors used to detect the load location and reduces costs.

[0026] (11) In any of (1) to (9) above, the loading location detection unit may include a first detection unit that detects the loading location when the forklift is facing sideways toward the loading location, and a second detection unit that detects the loading location when the forklift is facing forward toward the loading location, and the position and attitude calculation unit may calculate the position and attitude of the loading location relative to the forklift based on detection data from the first detection unit when the forklift is in the starting position, and may calculate the position and attitude of the loading location relative to the forklift based on detection data from the second detection unit when the forklift is in the loading location.

[0027] In this configuration, when the forklift is in the starting position, the first detector detects the loading area while the forklift is facing sideways toward the loading area. The forklift is then controlled to approach the loading area. Therefore, even if the space in front of the loading area is narrow, the forklift can be driven to the loading area in front of the loading area and the loading area can be loaded.

[0028] (12) In any of the above (1) to (11), the loading area may be a location provided on the bed of a truck.

[0029] With this configuration, the total loading time is reduced when placing many pallets on the loading platform of a truck. [Effects of the Invention]

[0030] According to the present invention, the total loading and unloading time can be reduced. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a side view showing a forklift to which a cargo handling control device according to an embodiment of the present invention is applied. [Figure 2] 1 is a block diagram showing the configuration of a cargo handling control device according to a first embodiment of the present invention. [Figure 3] 10 is a schematic plan view showing the operation of a forklift moving from a start position to a loading position and loading the load. FIG. [Figure 4] 3 is a flowchart showing the procedure of a load placement control process executed by the controller shown in FIG. 2. [Figure 5] 5 is a flowchart showing the details of step S103 shown in FIG. 4. [Figure 6] 1A and 1B are diagrams (including cross-sectional and front views) showing examples of patterns in which pallet loading cannot be successful. [Figure 7] FIG. 2 is a perspective view showing the dimensions of the fork holes and forks of the pallet. [Figure 8] 5 is a flowchart showing details of step S112 shown in FIG. 4. [Figure 9] FIG. 10 is a plan view showing an example of a pattern in which the success rate of loading is increased by re-approaching the forklift to the loading position. [Figure 10] FIG. 10 is a schematic plan view showing the operation of a forklift truck making a re-approach to a loading position when the forklift truck fails to approach the loading position; [Figure 11] FIG. 5 is a block diagram showing the configuration of a cargo handling control device according to a second embodiment of the present invention. [Figure 12] 12 is a flowchart showing the procedure of a load placement control process executed by the controller shown in FIG. 11. [Figure 13] FIG. 10 is a schematic plan view showing the operation of a forklift truck making a re-approach to a loading position when the forklift truck fails to approach the loading position; [Figure 14] FIG. 10 is a block diagram showing the configuration of a cargo handling control device according to a third embodiment of the present invention. [Figure 15] 15 is a flowchart showing the procedure of a load placement control process executed by the controller shown in FIG. 14. [Figure 16] 10 is a schematic plan view showing the operation of a forklift moving from a start position to a loading position and loading the load. FIG. [Figure 17] FIG. 10 is a schematic plan view showing the operation of a forklift truck making a re-approach to a loading position when the forklift truck fails to approach the loading position; DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are designated by the same reference numerals, and redundant description will be omitted.

[0033] Fig. 1 is a side view showing a forklift to which a cargo handling control device according to an embodiment of the present invention is applied. In Fig. 1, the forklift 1 is a reach forklift. Here, the left-right direction (lateral direction) of the forklift 1 is defined as the X-axis direction, the front-rear direction of the forklift 1 is defined as the Y-axis direction, and the up-down direction (height direction) of the forklift 1 is defined as the Z-axis direction (see Figs. 6 and 8). The forklift 1 is equipped with a traveling device 2 and a cargo handling device 3.

[0034] The traveling device 2 has a body 4, a pair of left and right reach legs 5 extending forward from the bottom of the body 4, left and right front wheels 6 disposed at the tip (front end) of each reach leg 5, and rear wheels 7 serving as drive and steering wheels disposed at the rear left side of the body 4. A caster wheel (not shown) is disposed at the rear right side of the body 4.

[0035] The cargo handling device 3 has a mast 8 that is arranged between each reach leg 5 and is movable in the fore-and-aft direction (Y-axis direction) along the reach leg 5, a pair of left and right forks 12 that are attached to the mast 8 via lift brackets 9 and load brackets 10 so that they can move (raise and lower) in the up-and-down direction (Z-axis direction) and hold a pallet 11, a lift cylinder 13 that raises and lowers the forks 12 via the lift brackets 9 and load brackets 10, a reach cylinder 14 (see Figure 2) that moves the mast 8 in the fore-and-aft direction, thereby moving the forks 12 in the fore-and-aft direction (advancing and retreating), and a side shift cylinder 15 (see Figure 2) that moves the forks 12 sideways (X-axis direction) via the load bracket 10.

[0036] The pallet 11 is, for example, a flat pallet made of plastic or wood. The pallet 11 has a square or approximately square shape in a plan view. A load M is placed on the pallet 11. The pallet 11 is provided with a pair of fork holes 11a (see FIG. 6) into which forks 12 are inserted.

[0037] 2 is a block diagram showing the configuration of a cargo handling control device according to a first embodiment of the present invention. In FIG. 2, a cargo handling control device 20 of this embodiment is a device that performs cargo handling by automatically driving a forklift 1.

[0038] 3, the cargo handling control device 20 places the pallet 11 held by the forks 12 (hereinafter, sometimes referred to as held pallet 11A) on the loading platform 18 of the truck 17, that is, performs so-called loading. The loading of the pallets 11 is performed, for example, sequentially from the front side to the rear side of the truck 17.

[0039] The cargo handling control device 20 is a device for depositing cargo by moving the forklift 1, which holds the pallet 11 with its forks 12, from a start position P0 toward a cargo deposit point 18a provided on the loading platform 18 of the truck 17. The start position P0 is a position on the side of the truck 17 where the forklift 1 starts moving toward the cargo deposit point 18a.

[0040] The loading area 18a is a location on the top surface of the loading platform 18 of the truck 17 where the holding pallet 11A is placed. When no pallet 11 has been placed on the loading platform 18, the loading area 18a is an area at the front end of the loading platform 18. When a pallet 11 has already been placed on the loading platform 18, the loading area 18a is an area adjacent to the rear of the existing pallet 11.

[0041] The cargo handling control device 20 includes a camera 21, a laser sensor 22, a map storage unit 23, a travel drive unit 24, a lift drive unit 25, a reach drive unit 26, a side shift drive unit 27, an alarm 28, and a controller 30. These are mounted on the forklift 1.

[0042] The camera 21 is an image sensor that captures an image within a predetermined angle range including the area in front of the forklift 1 and outputs image data. The camera 21 captures an image of an area including the loading area 18a on the loading platform 18 of the truck 17. The camera 21 constitutes a loading area detection unit that detects the loading area 18a on the loading platform 18. The camera 21 detects the loading area 18a when the forklift 1 is facing forward relative to the loading platform 18 and outputs image data that is detection data.

[0043] The laser sensor 22 irradiates the area around the forklift 1 with a laser and receives the reflected laser light to detect the distance to an object present around the forklift 1 and output the detection data. As the laser sensor 22, for example, a LIDAR (light detection and ranging) or a laser range finder is used.

[0044] The map storage unit 23 stores map data of an area where cargo handling is performed by the forklift 1. The map data includes buildings, pillars, shelves, walls, etc. The map data is created in advance by the laser sensor 22.

[0045] The traveling drive unit 24 is a drive unit that drives the forklift 1. The traveling drive unit 24 includes, for example, a traveling motor that rotates the rear wheels 7 and a steering motor that steers the rear wheels 7, although these are not shown.

[0046] The lift drive unit 25 is a drive unit that extends and retracts the lift cylinder 13. The lift drive unit 25 is, for example, an electromagnetic control valve (not shown) that is arranged between a hydraulic pump and the lift cylinder 13.

[0047] The reach drive unit 26 is a drive unit that extends and retracts the reach cylinder 14. The reach drive unit 26 is, for example, an electromagnetic control valve (not shown) that is arranged between the hydraulic pump and the reach cylinder 14.

[0048] The side shift drive unit 27 is a drive unit that extends and retracts the side shift cylinder 15. Although not shown, the side shift drive unit 27 is, for example, an electromagnetic control valve that is arranged between a hydraulic pump and the side shift cylinder 15.

[0049] The alarm 28 is a device that issues an alarm when an abnormality occurs during loading and unloading operations. The alarm 28 issues an alarm by sound or visual indication.

[0050] The controller 30 is composed of a CPU, RAM, ROM, an input / output interface, etc. The controller 30 has a loading platform position / attitude calculation unit 31, a loading availability determination unit 32, a self-position estimation unit 33, a route generation unit 34, a guidance control unit 35, an approach determination unit 36, a re-route generation unit 37, a re-guidance control unit 38, a re-approach determination unit 39, a count determination unit 40, a loading control unit 41, an abnormal stop control unit 42, and an alarm control unit 43.

[0051] The platform position and orientation calculation unit 31 calculates the position and orientation of the loading area 18a on the platform 18 of the truck 17 relative to the forklift 1 based on image data from the camera 21. The platform position and orientation calculation unit 31 calculates the position and orientation of the loading area 18a on the platform 18 relative to the forklift 1 at the start position P0 and the loading position P (see FIG. 3). The loading position P is a position just before the loading area 18a. The platform position and orientation calculation unit 31 constitutes a position and orientation calculation unit that calculates the position and orientation of the loading area 18a relative to the forklift 1.

[0052] The loading possibility determination unit 32 determines whether there is a possibility of successfully loading the holding pallet 11A at the loading location 18a based on the position and posture of the loading location 18a of the loading platform 18 relative to the forklift 1 calculated by the loading platform position and posture calculation unit 31.

[0053] The loading possibility determination unit 32 determines whether there is a possibility of successfully loading the holding pallet 11A at the loading location 18a based on the position and posture of the loading location 18a relative to the forklift 1 calculated by the loading platform position and posture calculation unit 31 when the forklift 1 is at the starting position P0.

[0054] The loading possibility determination unit 32 determines that there is a possibility that the loading of the holding pallet 11A at the loading location 18a will be successful when the pitch angle of the forklift 1 with respect to the loading location 18a is equal to or less than a predetermined pitch angle threshold and the roll angle of the forklift 1 with respect to the loading location 18a is equal to or less than a predetermined roll angle threshold.The loading possibility determination unit 32 determines that there is no possibility that the loading of the holding pallet 11A at the loading location 18a will be successful when the pitch angle of the forklift 1 with respect to the loading location 18a is greater than the pitch angle threshold or when the roll angle of the forklift 1 with respect to the loading location 18a is greater than the roll angle threshold.

[0055] The self-position estimation unit 33 estimates the self-position of the forklift 1 based on the detection data of the laser sensor 22 and the map data stored in the map storage unit 23. Specifically, the self-position estimation unit 33 uses, for example, a SLAM (simultaneous localization and mapping) method to match the detection data of the laser sensor 22 with the map data and estimate the self-position of the forklift 1. SLAM is a self-position estimation technology that estimates the self-position using sensor data and map data.

[0056] The path generating unit 34 generates a travel path D (see FIG. 3(a)) from the start position P0 to the load placement position P based on the position and posture of the load placement location 18a of the platform 18 relative to the forklift 1 calculated by the platform position and posture calculating unit 31 and the self-position of the forklift 1 estimated by the self-position estimating unit 33. The path generating unit 34 generates a travel path D that moves the forklift 1 forward from the start position P0 to the load placement position P.

[0057] The guidance control unit 35 controls the traveling drive unit 24 to guide the forklift 1 to the loading position P according to the traveling route D generated by the route generation unit 34 based on the self-position of the forklift 1 estimated by the self-position estimation unit 33.

[0058] The guidance control unit 35 cooperates with the self-position estimation unit 33 and the path generation unit 34 to constitute an approach control unit that controls the forklift 1 to approach the loading position P just before the loading position 18a based on the position and posture of the loading position 18a relative to the forklift 1 calculated by the loading position and posture calculation unit 31 when the forklift 1 is at the starting position P0.

[0059] When the loading possibility determination unit 32 determines that there is a possibility that the loading of the pallet 11 at the loading location 18a will be successful, the approach control unit controls the forklift 1 to approach the loading location P based on the position and posture of the loading location 18a relative to the forklift 1 calculated by the loading platform position and posture calculation unit 31 when the forklift 1 is at the starting position P0.

[0060] The approach determination unit 36 ​​determines whether the forklift 1 has successfully approached the loading position P based on the position and posture of the loading point 18a on the loading platform 18 relative to the forklift 1 calculated by the loading platform position and posture calculation unit 31 when the forklift 1 reaches the loading position P.

[0061] The approach determination unit 36 ​​determines that the approach of the forklift 1 to the load placement position P has been successful when the amount of lateral deviation of the forklift 1 from the load placement position 18a is equal to or less than a predetermined specified amount and the yaw angle of the forklift 1 relative to the load placement position 18a is equal to or less than a predetermined yaw angle threshold. The approach determination unit 36 ​​determines that the approach of the forklift 1 to the load placement position P has been unsuccessful when the amount of lateral deviation of the forklift 1 from the load placement position 18a is greater than the specified amount or when the yaw angle of the forklift 1 relative to the load placement position 18a is greater than the yaw angle threshold.

[0062] When the approach determination unit 36 ​​determines that the approach of the forklift 1 to the loading position P has failed, the re-route generation unit 37 regenerates a travel route to the loading position P based on the position and orientation of the loading area 18a of the loading platform 18 relative to the forklift 1 calculated by the platform position and orientation calculation unit 31 at the loading position P and the self-position of the forklift 1 estimated by the self-position estimation unit 33. The re-route generation unit 37 generates a travel route that causes the forklift 1 to move backward toward the loading position P and then forward toward the loading position P (see FIG. 10).

[0063] The re-guiding control unit 38 controls the traveling drive unit 24 to re-guide the forklift 1 to the loading position P according to the traveling route regenerated by the re-route generation unit 37 based on the self-position of the forklift 1 estimated by the self-position estimation unit 33.

[0064] The re-guiding control unit 38 cooperates with the self-position estimation unit 33 and the re-route generation unit 37 to constitute a re-approach control unit that controls the forklift 1 to re-approach the loading position P based on the position and posture of the loading location 18a relative to the forklift 1 calculated by the loading platform position and posture calculation unit 31 when the approach determination unit 36 ​​determines that the forklift 1's approach to the loading position P has failed.

[0065] If it is determined that the forklift 1 has failed to approach the loading position P, the re-approach control unit controls the forklift 1 to temporarily retreat to the loading position P and then re-approach the loading position P based on the position and posture of the loading area 18a for the forklift 1 calculated by the loading platform position and posture calculation unit 31 when the forklift 1 is at the loading position P.

[0066] The re-approach determination unit 39 determines whether the forklift 1 has successfully re-approached the loading position P based on the position and posture of the loading point 18a on the loading platform 18 relative to the forklift 1 calculated by the loading platform position and posture calculation unit 31 when the forklift 1 reaches the loading position P again.

[0067] When the re-approach determination unit 39 determines that the forklift 1 has failed in re-approaching the loading position P, the number determination unit 40 determines whether the number of re-approaches of the forklift 1 to the loading position P has reached a predetermined upper limit value.

[0068] When the approach determination unit 36 ​​determines that the forklift 1 has successfully approached the loading position P, the loading control unit 41 controls the lift drive unit 25, the reach drive unit 26, and the side shift drive unit 27 to load the holding pallet 11A at the loading location 18a on the loading platform 18. Furthermore, when the re-approach determination unit 39 determines that the forklift 1 has successfully re-approached the loading position P, the loading control unit 41 controls the lift drive unit 25, the reach drive unit 26, and the side shift drive unit 27 to load the holding pallet 11A at the loading location 18a on the loading platform 18.

[0069] The abnormal stop control unit 42 controls the traveling drive unit 24 to abnormally stop the traveling of the forklift 1 when the loading possibility determination unit 32 determines that there is no possibility of successfully depositing the holding pallet 11A at the loading location 18a on the loading platform 18. In addition, the abnormal stop control unit 42 controls the traveling drive unit 24 to abnormally stop the traveling of the forklift 1 when the number of times determination unit 40 determines that the number of times the forklift 1 has re-approached the loading position P has reached an upper limit.

[0070] The alarm control unit 43 issues an alarm by outputting an abnormality notification signal to the alarm 28 when the loading possibility determination unit 32 determines that there is no possibility of successful loading of the holding pallet 11A at the loading location 18a on the loading platform 18. In addition, the alarm control unit 43 issues an alarm by outputting an abnormality notification signal to the alarm 28 when the number of times determination unit 40 determines that the number of re-approaches of the forklift 1 to the loading position P has reached an upper limit.

[0071] Fig. 4 is a flowchart showing the steps of the load placement control process executed by the controller 30. This process is executed when the forklift 1, holding the pallet 11 with the forks 12, reaches the start position P0, as shown in Fig. 3(a). When the forklift 1 reaches the start position P0, it faces the loading platform 18 of the truck 17, and the camera 21 can detect the loading location 18a on the loading platform 18.

[0072] 4, the controller 30 first acquires image data from the camera 21 (step S101). Then, the controller 30 calculates the position and attitude of the loading area 18a of the loading platform 18 relative to the forklift 1 based on the image data from the camera 21 (step S102).

[0073] Next, the controller 30 determines whether there is a possibility that the holding pallet 11A will be successfully placed at the placement location 18a, based on the position and attitude of the placement location 18a of the platform 18 relative to the forklift 1 (step S103).

[0074] Fig. 5 is a flowchart showing the details of step S103. In Fig. 5, the controller 30 first determines whether the pitch angle of the forklift 1 relative to the load placement location 18a of the platform 18 is equal to or less than a predetermined pitch angle threshold value θx, based on the attitude of the load placement location 18a of the platform 18 relative to the forklift 1 obtained in step S102 (step S151).

[0075] As shown in Figure 6(a), the pitch angle of the forklift 1 is the angle of deviation around the X-axis of the forklift 1. The pitch angle threshold θx is the angle at which the fork 12 can be pulled out from the holding pallet 11A placed in the loading area 18a of the loading platform 18, even when the forklift 1 is tilted around the X-axis with respect to the loading platform 18.

[0076] Specifically, as shown in Figure 7, if the thickness of the fork 12 is Fh, the height of the fork hole 11a of the pallet 11 is Ph, and the depth length of the fork hole 11a is Pd, when the pitch angle of the forklift 1 relative to the loading platform 18, expressed by the following formula, is greater than the pitch angle threshold θx, even if you try to pull the fork 12 out of the pallet 11 placed in the loading area 18a of the loading platform 18, the fork 12 will scrape against the inner wall surface of the pallet 11 and will not come out (see Figure 6(a)).

[0077]

number

[0078] As shown in Figure 6(b), the roll angle of the forklift 1 is the angle of deviation around the Y axis of the forklift 1. The roll angle threshold θy is the angle at which the holding pallet 11A hits the adjacent pallet 11 when the forks 12 are moved by the side shift cylinder 15 toward the adjacent pallet 11 already placed on the loading platform 18.

[0079] Specifically, as shown in Figures 6(b) and 7, if the width of the pallet 11 is W, the height of the pallet 11 is H, and the distance of the perpendicular line from the center G of the front surface 11b of the pallet 11 to the loading platform 18 is h, when the roll angle of the forklift 1 relative to the loading platform 18, expressed by the following equation, is greater than the roll angle threshold θy, when the forks 12 are moved toward the adjacent pallet 11 by the side shift cylinder 15, the holding pallet 11A will not hit the adjacent pallet 11, and both pallets 11 will overlap each other (see Figure 6(b)).

[0080]

number

[0081] When the controller 30 determines in step S151 that the pitch angle of the forklift 1 relative to the loading location 18a on the loading platform 18 is not equal to or less than the pitch angle threshold θx, or when the controller 30 determines in step S152 that the roll angle of the forklift 1 relative to the loading location 18a on the loading platform 18 is not equal to or less than the roll angle threshold θy, it determines that there is no possibility of successfully loading the holding pallet 11A onto the loading location 18a (step S154).

[0082] Returning to FIG. 4, when the controller 30 determines in step S103 that there is a possibility that the placement of the holding pallet 11A at the placement location 18a of the loading platform 18 will be successful, the controller 30 estimates the current position of the forklift 1 based on the detection data of the laser sensor 22 and the map data stored in the map memory unit 23 (step S104).

[0083] Next, as shown in Fig. 3(a), the controller 30 generates a travel route D from the start position P0, which is the current position of the forklift 1, to the loading position P (step S105). Next, the controller 30 controls the travel drive unit 24 to cause the forklift 1 to approach the loading position P according to the travel route D (step S106).

[0084] Next, the controller 30 estimates the current position of the forklift 1 based on the detection data of the laser sensor 22 and the map data (step S107). Then, the controller 30 determines whether the forklift 1 has reached the loading position P based on the current position of the forklift 1 (step S108). If the controller 30 determines that the forklift 1 has not reached the loading position P, it executes the above step S106 again.

[0085] 3(b), when the controller 30 determines that the forklift 1 has reached the loading position P, it controls the traveling drive unit 24 to stop the traveling of the forklift 1 (step S109). Next, the controller 30 acquires image data from the camera 21 (step S110). Then, the controller 30 calculates the position and attitude of the loading area 18a of the loading platform 18 relative to the forklift 1 based on the image data from the camera 21 (step S111).

[0086] Next, the controller 30 determines whether the forklift 1 has successfully approached the loading position P based on the position and attitude of the loading position 18a of the loading platform 18 relative to the forklift 1 (step S112).

[0087] Fig. 8 is a flowchart showing the details of step S112. In Fig. 8, the controller 30 determines whether the amount of lateral displacement of the forklift 1 with respect to the load placement area 18a of the loading platform 18 is equal to or less than a predetermined specified amount J, based on the position of the load placement area 18a of the loading platform 18 with respect to the forklift 1 (step S161).

[0088] The lateral deviation of the forklift 1 is the deviation in the lateral direction (X-axis direction) of the forklift 1. The specified amount J is a value that allows the forks 12 to be moved laterally by the side shift cylinders 15 so that the holding pallet 11A can abut against an adjacent pallet 11 that is already placed on the loading platform 18. The specified amount J is, for example, the maximum lateral movement of the forks 12 from the center position in the left-right direction of the forklift 1.

[0089] As shown in Figure 9(a), when the lateral displacement of the forklift 1 relative to the loading area 18a of the loading platform 18 is greater than the specified amount J, even if the forks 12 are moved laterally by the side shift cylinder 15, the holding pallet 11A cannot hit the adjacent pallet 11.

[0090] When the controller 30 determines that the amount of lateral displacement of the forklift 1 relative to the loading location 18a of the loading platform 18 is less than the specified amount J, it determines whether the yaw angle of the forklift 1 relative to the loading location 18a of the loading platform 18 is less than a predetermined yaw angle threshold θz based on the attitude of the loading location 18a of the loading platform 18 relative to the forklift 1 (step S162).

[0091] As shown in Figure 9(b), the yaw angle of the forklift 1 is the angle of deviation around the Z axis of the forklift 1. The yaw angle threshold θz is an angle at which the side shift cylinder 15 can move the forks 12 laterally to align the holding pallet 11A with the adjacent pallet 11 already placed on the loading platform 18.

[0092] Specifically, as shown in Figure 7, if the width of the forks 12 is Fw, the width of the fork holes 11a of the pallet is Pw, and the depth of the fork holes 11a is Pd, when the yaw angle of the forklift 1 relative to the loading platform 18 expressed by the following formula is greater than the yaw angle threshold θz, even if the forks 12 are moved toward the adjacent pallet 11 by the side shift cylinder 15, the holding pallet 11A cannot be aligned with the adjacent pallet 11 (see Figure 9(b)).

[0093]

number

[0094] If the controller 30 determines in step S161 that the amount of lateral displacement of the forklift 1 relative to the loading location 18a on the loading platform 18 is not less than the specified amount J, or if it determines in step S162 that the yaw angle of the forklift 1 relative to the loading location 18a on the loading platform 18 is not less than the yaw angle θz, it determines that the approach of the forklift 1 to the loading location P has failed (step S164).

[0095] 4, when the controller 30 determines in step S112 that the forklift 1 has successfully approached the loading position P, it controls the lift drive unit 25, the reach drive unit 26, and the side shift drive unit 27 to place the holding pallet 11A in the loading location 18a on the loading platform 18 (step S113). At this time, the controller 30 controls the lift drive unit 25 and the reach drive unit 26 to place the holding pallet 11A in the loading location 18a on the loading platform 18, and also controls the side shift drive unit 27 to move the holding pallet 11A toward the adjacent pallet 11.

[0096] Next, the controller 30 controls the traveling drive unit 24 and the lifting drive unit 25 so as to pull the forks 12 out of the pallet 11 placed in the loading area 18a of the loading platform 18 (step S114). At this time, the controller 30 controls the lifting drive unit 25 so as to prevent the forks 12 from hitting the inner wall surface of the pallet 11, and also controls the traveling drive unit 24 so as to move the forklift 1 backward.

[0097] When the controller 30 determines in step S112 that the forklift 1 has failed to approach the loading position P, it estimates the current position of the forklift 1 based on the detection data of the laser sensor 22 and the map data stored in the map memory unit 23 (step S115).

[0098] 10, the controller 30 again generates a travel route to the loading position P (step S116). At this time, the controller 30 generates a travel route that moves the forklift 1 backward a predetermined distance from the current position of the loading position P and then forward to the loading position P. Next, the controller 30 controls the traveling drive unit 24 so that the forklift 1 approaches the loading position P again along the travel route (step S117).

[0099] Next, the controller 30 estimates the current position of the forklift 1 based on the detection data of the laser sensor 22 and the map data (step S118). Then, the controller 30 determines whether the forklift 1 has reached the loading position P based on the current position of the forklift 1 (step S119). If the controller 30 determines that the forklift 1 has not reached the loading position P, it executes the above step S117 again.

[0100] When the controller 30 determines that the forklift 1 has reached the loading position P, it controls the traveling drive unit 24 to stop the traveling of the forklift 1 (step S120). Next, the controller 30 acquires image data from the camera 21 (step S121). Then, the controller 30 calculates the position and attitude of the loading area 18a of the loading platform 18 relative to the forklift 1 based on the image data from the camera 21 (step S122).

[0101] Next, the controller 30 determines whether the forklift 1 has successfully re-approached the loading position P based on the position and posture of the loading position 18a of the loading platform 18 relative to the forklift 1 (step S123). Details of step S123 are the same as those of step S112 above.

[0102] If the controller 30 determines that the forklift 1 has successfully re-approached the loading position P, it executes step S113. If the controller 30 determines that the forklift 1 has failed to re-approach the loading position P, it determines whether the number of re-approaches (number of retries) made by the forklift 1 to the loading position P has reached a predetermined upper limit (step S124). The upper limit can be set as appropriate and may be one or multiple times.

[0103] If the controller 30 determines that the number of re-approaches of the forklift 1 to the loading position P has not reached the upper limit, it executes the above-described step S115 again. If the controller 30 determines that the number of re-approaches of the forklift 1 to the loading position P has reached the upper limit, it controls the traveling drive unit 24 to bring the forklift 1 to an abnormal stop (step S125). Then, the controller 30 outputs an abnormality notification signal to the alarm 28 (step S126).

[0104] The controller 30 also executes steps S125 and S126 when it determines in step S103 that there is no possibility of successful placement of the holding pallet 11A at the placement location 18a of the loading platform 18.

[0105] Here, the loading platform position / attitude calculation unit 31 executes steps S101, S102, S110, S111, S121, and S122. The loading availability determination unit 32 executes step S103. The self-position estimation unit 33 executes steps S104, S107, S115, and S118. The route generation unit 34 executes step S105. The guidance control unit 35 executes steps S106 to S109. The approach determination unit 36 ​​executes step S112. The re-route generation unit 37 executes step S116. The re-guidance control unit 38 executes steps S117 to S120. The re-approach determination unit 39 executes step S123. The number of times determination unit 40 executes step S124. The loading control unit 41 executes steps S113 and S114. The abnormal stop control unit 42 executes step S125. The warning control unit 43 executes step S126.

[0106] In the cargo handling control device 20 described above, the forklift 1 holding the pallet 11 with the forks 12 travels toward the truck 17, as shown in Figure 3(a), and stops at a starting position P0 a certain distance from the side of the truck 17, facing the loading platform 18 of the truck 17.

[0107] In this state, the camera 21 captures an image of an area including the placement location 18a on the loading platform 18. Then, based on the image data from the camera 21, the position and attitude of the placement location 18a on the loading platform 18 relative to the forklift 1 are calculated. Then, based on the position and attitude of the placement location 18a on the loading platform 18 relative to the forklift 1, it is determined whether there is a possibility that the placement of the holding pallet 11A at the placement location 18a will be successful. If it is determined that there is a possibility that the placement of the holding pallet 11A will be successful, a travel route D to a placement position P just before the placement location 18a is generated. Then, the forklift 1 approaches the placement position P along the travel route D.

[0108] 3(b), when the forklift 1 reaches the loading position P, the camera 21 again captures an image of the area including the loading area 18a on the loading platform 18. Then, based on the image data from the camera 21, the position and orientation of the loading area 18a on the loading platform 18 relative to the forklift 1 are calculated, and from the calculation results, it is determined whether the forklift 1 has successfully approached the loading position P.

[0109] When the forklift 1 successfully approaches the loading position P, the loading of the holding pallet 11A is performed, as shown in Figure 3(c). Specifically, the forklift 1 is moved forward and the forks 12 are moved forward by the reach cylinders 14, so that the holding pallet 11A is positioned directly above the loading position 18a on the loading platform 18. Then, the forks 12 are lowered by the lift cylinders 13 and moved toward the adjacent pallet 11 by the side shift cylinders 15, so that the holding pallet 11A is placed in the loading position 18a on the loading platform 18 while abutting against the adjacent pallet 11. Then, the forks 12 are pulled out of the fork holes 11a of the pallet 11, and the forklift 1 travels to the designated location.

[0110] On the other hand, as shown in Figure 10(a), if the forklift 1 deviates from the loading position 18a on the loading platform 18 and the forklift 1 fails to approach the loading position P, a new travel path to the loading position P is generated. Then, as shown in Figures 10(b) and 10(c), the forklift 1 approaches the loading position P again along the new travel path. Then, if the forklift 1 successfully re-approaches the loading position P, the holding pallet 11A is loaded.

[0111] Incidentally, there are two patterns in which the placement of the pallet 11 fails: one in which the success rate of placement increases by re-approaching (retrying) the forklift 1 to the placement position P, and another in which the success rate of placement does not increase even if the forklift 1 re-approaches the placement position P.

[0112] 9, a pattern in which the success rate of loading is increased by retrying the forklift 1's approach occurs due to an error in self-location estimation or guidance error of the forklift 1, and the forklift 1 is not in a position or posture that allows it to load the load at the loading location 18a on the loading platform 18 of the truck 17. Examples of such a situation include a situation in which the amount of lateral deviation (amount of deviation in the X-axis direction) of the forklift 1 relative to the loading location 18a on the loading platform 18 is large, and a situation in which the yaw angle (angle of tilt around the Z-axis) of the forklift 1 relative to the loading location 18a on the loading platform 18 is large.

[0113] On the other hand, a pattern in which the success rate of loading does not increase even when the forklift 1 retries its approach is a state in which the loading platform 18 of the truck 17 is tilted, as shown in Figure 6, and the forklift 1 fails to load the pallet 11 even though it travels along the ideal path and reaches the front of the loading location 18a on the loading platform 18. Examples of such a state include a state in which the pitch angle (tilt angle around the X-axis) of the forklift 1 relative to the loading location 18a on the loading platform 18 is large, and a state in which the roll angle (tilt angle around the Y-axis) of the forklift 1 relative to the loading location 18a on the loading platform 18 is large.

[0114] The amount of deviation of the forklift 1 in the Y-axis direction from the load placement area 18a on the loading platform 18 can be addressed by changing the front-to-rear position of the forks 12 with the reach cylinder 14 or by moving the forklift 1 forward or backward to change the front-to-rear position of the forks 12. The amount of deviation of the forklift 1 in the Z-axis direction from the load placement area 18a on the loading platform 18 can be addressed by changing the height position of the forks 12 with the lift cylinder 13.

[0115] If the success rate of loading is high, the number of times abnormality procedures are performed can be reduced and the loading cycle time can be shortened by performing a retry of the forklift 1's approach to the loading position P. However, if the success rate of loading is not high but the forklift 1's approach to the loading position P is retried, the response to the abnormality procedure will be delayed by the time it takes for the forklift 1 to retry its approach compared to when the forklift 1's travel is immediately stopped due to an abnormality, resulting in an increase in the loading cycle time.

[0116] To address this issue, in this embodiment, the placement location 18a of the loading platform 18 is detected at the start position P0, and the position and orientation of the placement location 18a relative to the forklift 1 are calculated. Then, based on the position and orientation of the placement location 18a relative to the forklift 1, the forklift 1 is controlled to approach a placement location P just before the placement location 18a. When the forklift 1 reaches the placement location P, the placement location 18a of the loading platform 18 is detected again, and the position and orientation of the placement location 18a relative to the forklift 1 are calculated. Then, based on the position and orientation of the placement location 18a relative to the forklift 1, it is determined whether the forklift 1 has successfully approached the placement location P. If it is determined that the forklift 1 has successfully approached the placement location P, the forklift 1 is controlled to place the pallet 11 at the placement location 18a. If it is determined that the forklift 1 has failed to approach the placement position P, the forklift 1 is controlled to re-approach the placement position P based on the position and attitude of the placement location 18a relative to the forklift 1. Furthermore, based on the position and attitude of the placement location 18a relative to the forklift 1, it is determined whether there is a possibility that the pallet 11 will be successfully placed at the placement location 18a. If it is determined that there is no possibility that the pallet 11 will be successfully placed at the placement location 18a, the forklift 1 is controlled to make an abnormal stop of its travel. In this way, if it is determined that there is no possibility that the pallet 11 will be successfully placed at the placement location 18a, by making the forklift 1 make an abnormal stop of its travel, it is possible to avoid a wasteful approach of the forklift 1. This reduces the total time required to deal with the abnormality and the total time required for handling cargo.

[0117] Furthermore, in this embodiment, when the forklift 1 is at the start position P0, it is determined whether there is a possibility that the pallet 11 will be successfully placed at the placement location 18a. If it is determined that there is no possibility that the pallet 11 will be successfully placed at the placement location 18a, the forklift 1 does not need to approach from the start position P0. This further reduces the total time required to deal with the abnormality and the time required for handling the cargo.

[0118] In addition, in this embodiment, if the loading area 18a of the loading platform 18 is tilted more than necessary, causing the pitch angle of the forklift 1 relative to the loading area 18a to exceed the pitch angle threshold θx, or if the roll angle of the forklift 1 relative to the loading area 18a to exceed the roll angle threshold θy, there is no need to perform a wasteful approach by the forklift 1.

[0119] In addition, in this embodiment, if the lateral deviation of the forklift 1 relative to the loading location 18a exceeds the specified amount J or the yaw angle of the forklift 1 relative to the loading location 18a exceeds the yaw angle threshold θz due to, for example, a self-position estimation error or a guidance error of the forklift 1, the probability that the forklift 1 will reach an appropriate loading location P just before the loading location 18a is increased by having the forklift 1 approach the loading location P again.

[0120] In addition, in this embodiment, if the forklift 1 fails to re-approach the loading position P, the probability that the forklift 1 will reach the appropriate loading position P just before the loading area 18a can be further increased by having the forklift 1 re-approach the loading position P.

[0121] Furthermore, in this embodiment, when the number of re-approaches of the forklift 1 to the loading position P reaches an upper limit, the forklift 1 is brought to an abnormal stop, thereby eliminating the need to re-approach the forklift 1 more than necessary. This further reduces the total time required to deal with the abnormality and the loading and unloading time.

[0122] Furthermore, in this embodiment, if the forklift 1 fails to approach the loading position P, the loading position 18a of the loading platform 18 is detected at the loading position P. Then, based on the position and posture of the loading position 18a relative to the forklift 1, the forklift 1 is controlled to temporarily retreat from the loading position P and then re-approach the loading position P. This allows the forklift 1 to re-approach the loading position P while ensuring sufficient positional accuracy of the loading position 18a relative to the forklift 1. This further increases the probability that the forklift 1 will reach an appropriate loading position P just before the loading position 18a.

[0123] Furthermore, in this embodiment, whether the forklift 1 is at the start position P0 or the loading position P, the loading position 18a is detected with the forklift 1 facing forward toward the loading position 18a on the loading platform 18. Therefore, the number of sensors used to detect the loading position 18a is kept to a minimum, thereby reducing costs.

[0124] Furthermore, in this embodiment, when a large number of pallets 11 are placed on the loading platform 18 of the truck 17, the total time required for dealing with abnormalities and the total time required for loading and unloading are reduced.

[0125] Fig. 11 is a block diagram showing the configuration of a cargo handling control device according to a second embodiment of the present invention. In Fig. 11, a cargo handling control device 20A of this embodiment includes a controller 30A instead of the controller 30 in the first embodiment.

[0126] The controller 30A has a loading platform position and attitude calculation unit 31, a loading possibility determination unit 32, a self-position estimation unit 33, a route generation unit 34, a guidance control unit 35, an approach determination unit 36, an evacuation control unit 45, a re-route generation unit 37A, a re-guidance control unit 38A, a re-approach determination unit 39, a count determination unit 40, a loading control unit 41, an abnormal stop control unit 42, and an alarm control unit 43.

[0127] When the approach determination unit 36 ​​determines that the approach of the forklift 1 to the loading position P has failed, the retraction control unit 45 controls the traveling drive unit 24 to temporarily retract the forklift 1 to the loading position P. The retraction control unit 45 controls the traveling drive unit 24 to temporarily retract the forklift 1 to the start position P0 from the loading position P.

[0128] If the approach determination unit 36 ​​determines that the approach of the forklift 1 to the loading position P has failed, the re-route generation unit 37A regenerates a travel route to the loading position P based on the position and orientation of the loading point 18a of the loading platform 18 relative to the forklift 1 calculated by the platform position and orientation calculation unit 31 at the start position P0 and the self-position of the forklift 1 estimated by the self-position estimation unit 33. Similar to the route generation unit 34, the re-route generation unit 37A generates a travel route that moves the forklift 1 forward toward the loading position P.

[0129] The re-guiding control unit 38A controls the traveling drive unit 24 to re-guide the forklift 1 to the loading position P according to the traveling route generated by the re-route generating unit 37A based on the self-position of the forklift 1 estimated by the self-position estimating unit 33.

[0130] The re-guiding control unit 38A cooperates with the self-position estimation unit 33, the evacuation control unit 45 and the re-route generation unit 37A to constitute a re-approach control unit that controls the forklift 1 to re-approach the loading position P based on the position and attitude of the loading point 18a of the loading platform 18 relative to the forklift 1 calculated by the loading platform position and attitude calculation unit 31 when the approach determination unit 36 ​​determines that the forklift 1's approach to the loading position P has failed.

[0131] If the re-approach control unit determines that the forklift 1 has failed in its approach to the loading position P, it controls the forklift 1 to retreat to the start position P0 relative to the loading position P, and then controls the forklift 1 to re-approach the loading position P based on the position and attitude of the loading point 18a of the loading platform 18 relative to the forklift 1 calculated by the platform position and attitude calculation unit 31 when the forklift 1 is at the start position P0.

[0132] Fig. 12 is a flowchart showing the procedure of the item receiving control process executed by the controller 30A, and corresponds to Fig. 4. In Fig. 12, the controller 30A executes steps S101 to S112 in the same manner as in the first embodiment.

[0133] If the controller 30A determines in step S112 that the forklift 1 has successfully approached the loading position P, it executes steps S113 and S114. If the controller 30A determines in step S112 that the forklift 1 has failed to approach the loading position P, it controls the traveling drive unit 24 so that the forklift 1 returns to the start position P0 (step S131), as shown in Figures 13(a) and 13(b).

[0134] Next, the controller 30A acquires image data from the camera 21 (step S132). Then, the controller 30A calculates the position and attitude of the loading area 18a of the loading platform 18 relative to the forklift 1 based on the image data from the camera 21 (step S133). Next, the controller 30A executes step S115, similar to the first embodiment.

[0135] Next, the controller 30A generates a new travel route from the start position P0, which is the current position of the forklift 1, to the loading position P (step S116A). Next, the controller 30A controls the travel drive unit 24 to cause the forklift 1 to approach the loading position P again along the travel route (step S117A). Then, the controller 30A executes steps S118 and onward, similar to the first embodiment.

[0136] Here, the loading platform position / attitude calculation unit 31 executes steps S101, S102, S110, S111, S132, S133, S121, and S122. The loading availability determination unit 32 executes step S103. The self-position estimation unit 33 executes steps S104, S107, S115, and S118. The route generation unit 34 executes step S105. The guidance control unit 35 executes steps S106 to S109. The approach determination unit 36 ​​executes step S112. The evacuation control unit 45 executes step S131. The re-route generation unit 37A executes step S116A. The re-guidance control unit 38A executes steps S117A to S120. The re-approach determination unit 39 executes step S123. The number of times determination unit 40 executes step S124. The depositing control unit 41 executes steps S113 and S114. The abnormal stop control unit 42 executes step S125. The alarm control unit 43 executes step S126.

[0137] In such a cargo handling control device 20A, as shown in Figure 13(a), when the forklift 1 reaches the loading position P, the camera 21 captures an image of the area including the loading area 18a on the loading platform 18, and as in the first embodiment described above, it is determined whether the forklift 1 has successfully approached the loading position P.

[0138] If the forklift 1 fails to approach the loading position P due to deviation of the forklift 1 from the loading position 18a on the loading platform 18, the forklift 1 returns to the start position P0 as shown in FIG. 13(b).

[0139] Then, at the start position P0, the camera 21 captures an image of an area including the loading location 18a on the loading platform 18, calculates the position and attitude of the loading location 18a on the loading platform 18 relative to the forklift 1, and generates a new travel route to the loading location P. Then, as shown in FIG. 13(c), the forklift 1 approaches the loading location P again along the travel route. The subsequent operations are the same as those in the first embodiment.

[0140] As described above, in this embodiment, if the forklift 1 fails to approach the loading position P, the forklift 1 is first controlled to retreat to the loading position P. Then, based on the position and posture of the loading area 18a of the loading platform 18 relative to the forklift 1, the forklift 1 is controlled to re-approach the loading position P. This shortens the travel distance of the forklift 1 after a travel path for the forklift 1 to re-approach the loading position P is set. This further increases the probability that the forklift 1 will reach an appropriate loading position P just before the loading area 18a.

[0141] In addition, in this embodiment, if the forklift 1 fails to approach the loading position P, the forklift 1 is temporarily retreated to the start position P0, which is known in advance as position information, thereby simplifying the processing of the controller 30A.

[0142] Fig. 14 is a block diagram showing the configuration of a cargo handling control device according to a third embodiment of the present invention. In Fig. 14, a cargo handling control device 20B of this embodiment is equipped with a side camera 51 and a front camera 52 instead of the camera 21 in the second embodiment.

[0143] The side camera 51 and the front camera 52 are image sensors that capture an image of an area including the cargo placement area 18a on the bed 18 of the truck 17. The side camera 51 and the front camera 52 constitute a cargo placement area detection unit that detects the cargo placement area 18a on the bed 18.

[0144] The side cameras 51 capture images within a predetermined angle range including the sides of the forklift 1 and output image data. The side cameras 51 are arranged on both the left and right sides of the forklift 1. The side cameras 51 are first detection units that detect the cargo placement location 18a on the loading platform 18 when the forklift 1 is facing sideways relative to the loading platform 18.

[0145] Like the camera 21, the front camera 52 captures an image within a predetermined angle range including the front of the forklift 1 and outputs image data. The front camera 52 is a second detection unit that detects the loading location 18a on the loading platform 18 when the forklift 1 is facing forward relative to the loading platform 18.

[0146] The cargo handling control device 20B also includes a controller 30B instead of the controller 30A in the second embodiment. The controller 30B includes a platform position / attitude calculation unit 31B, a cargo placement possibility determination unit 32, a self-position estimation unit 33, a route generation unit 34, a guidance control unit 35, an approach determination unit 36, an evacuation control unit 45, a re-route generation unit 37B, a re-guidance control unit 38B, a re-approach determination unit 39, a count determination unit 40, a cargo placement control unit 41, an abnormal stop control unit 42, and an alarm control unit 43.

[0147] The platform position and orientation calculation unit 31B calculates the position and orientation of the loading area 18a of the platform 18 relative to the forklift 1 at the start position P0 based on image data from the side camera 51. The platform position and orientation calculation unit 31B also calculates the position and orientation of the loading area 18a of the platform 18 relative to the forklift 1 at the loading position P based on image data from the front camera 52.

[0148] The platform position and attitude calculation unit 31B constitutes a position and attitude detection unit that calculates the position and attitude of the loading area 18a of the platform 18 relative to the forklift 1 based on the detection data of the side camera 51 when the forklift 1 is at the starting position P0, and calculates the position and attitude of the loading area 18a of the platform 18 relative to the forklift 1 based on the detection data of the front camera 52 when the forklift 1 is at the loading position P.

[0149] Fig. 15 is a flowchart showing the steps of the load placement control process executed by the controller 30B, and corresponds to Fig. 12. This process is executed when the forklift 1 reaches the start position P0, as shown in Fig. 16(a). When the forklift 1 reaches the start position P0, it faces sideways (sideways) relative to the loading platform 18 of the truck 17, and the side camera 51 can detect the loading location 18a on the loading platform 18.

[0150] 15, the controller 30B first acquires image data from the side camera 51 (step S101B). Then, the controller 30B calculates the position and attitude of the loading area 18a of the loading platform 18 based on the image data from the side camera 51 (step S102B). Then, the controller 30B executes steps S103 to S109, similar to the second embodiment.

[0151] After executing step S109, the controller 30B acquires image data from the front camera 52 (step S110B). Then, the controller 30B calculates the position and attitude of the loading area 18a of the loading platform 18 based on the image data from the front camera 52 (step S111B). Then, the controller 30B executes step S112, similar to the second embodiment.

[0152] If the controller 30B determines in step S112 that the forklift 1 has successfully approached the loading position P, it executes steps S113 and S114. If the controller 30B determines in step S112 that the forklift 1 has failed to approach the loading position P, it executes step S131 and then acquires image data from the side camera 51 (step S132B). Then, the controller 30B calculates the position and attitude of the loading area 18a of the loading platform 18 based on the image data from the side camera 51 (step S133B). Then, the controller 30B executes steps S115 to S120, similar to the second embodiment.

[0153] After executing step S120, the controller 30B acquires image data from the front camera 52 (step S121B). Then, the controller 30B calculates the position and attitude of the loading area 18a of the loading platform 18 based on the image data from the front camera 52 (step S122B). Then, the controller 30B executes steps S123 and onward, similar to the second embodiment.

[0154] Here, the loading platform position / attitude calculation unit 31B executes steps S101B, S102B, S110B, S111B, S132B, S133B, S121B, and S122B. The loading availability determination unit 32 executes step S103. The self-position estimation unit 33 executes steps S104, S107, S115, and S118. The route generation unit 34 executes step S105. The guidance control unit 35 executes steps S106 to S109. The approach determination unit 36 ​​executes step S112. The evacuation control unit 45 executes step S131. The re-route generation unit 37A executes step S116A. The re-guidance control unit 38A executes steps S117A to S120. The re-approach determination unit 39 executes step S123. The number of times determination unit 40 executes step S124. The deposit control unit 41 executes steps S113 and S114. The abnormal stop control unit 42 executes step S125. The alarm control unit 43 executes step S126.

[0155] In such a cargo handling control device 20B, as shown in Figure 16(a), the forklift 1 travels straight along the front-to-rear direction of the truck 17 on one side (here, the right side) of the truck 17. Then, when the forklift 1 reaches a start position P0 where it is oriented sideways relative to the loading platform 18 of the truck 17, the forklift 1 stops traveling.

[0156] In this state, the side camera 51 captures an image of an area including the loading area 18a on the loading platform 18. Then, based on the image data from the side camera 51, the position and attitude of the loading area 18a on the loading platform 18 relative to the forklift 1 are calculated, and a travel route D to a loading position P just before the loading area 18a is generated. At this time, as shown in FIG. 16(b), the travel route D is generated such that the forklift 1 travels backward straight for a certain distance and then moves forward while turning right toward the loading position P. Then, the forklift 1 approaches the loading position P along the travel route D.

[0157] 16(c), when the forklift 1 reaches the loading position P, the front camera 52 captures an image of an area including the loading area 18a on the loading platform 18. Then, based on the image data from the front camera 52, the position and attitude of the loading area 18a on the loading platform 18 relative to the forklift 1 are calculated, and it is determined whether the forklift 1 has successfully approached the loading position P.

[0158] As shown in Figure 17(a), if the forklift 1 fails to approach the loading position P, the forklift 1 returns to the start position P0. In this case, as shown in Figure 17(b), the forklift 1 reaches the start position P0 by moving backward while turning right with respect to the loading position P and then moving forward.

[0159] Then, the side camera 51 again captures an image of the area including the loading location 18a on the loading platform 18. Then, based on the image data from the side camera 51, the position and attitude of the loading location 18a on the loading platform 18 relative to the forklift 1 are calculated, and a travel route to the loading location P is generated again. Then, as shown in Figure 17(c), the forklift 1 again approaches the loading location P along the travel route.

[0160] As described above, in this embodiment, when the forklift 1 is at the start position P0, the side camera 51 detects the loading area 18a on the loading platform 18 while the forklift 1 faces sideways toward the loading area 18a. The forklift 1 is then controlled to approach the loading area P. Therefore, even if the space in front of the loading area 18a (to the side of the truck 17) is narrow, the forklift 1 can travel to the loading area P in front of the loading area 18a and load the load there.

[0161] In this embodiment, the processing corresponding to the controller 30A in the second embodiment is executed, but the processing corresponding to the controller 30 in the first embodiment may also be executed.

[0162] Although several embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, in the above embodiments, whether or not the placement of the holding pallet 11A at the placement location 18a is likely to be successful is determined based on the position and orientation of the placement location 18a of the loading platform 18 relative to the forklift 1 calculated when the forklift 1 is at the start position P0. However, the present invention is not limited to such an embodiment. For example, when the forklift 1 is between the start position P0 and the placement location P, the placement location 18a of the loading platform 18 may be detected, the position and orientation of the placement location 18a relative to the forklift 1 may be calculated, and based on the calculation results, whether or not the placement of the holding pallet 11A at the placement location 18a is likely to be successful.

[0163] In addition, in the second and third embodiments described above, when the forklift 1 fails to approach the loading position P, the forklift 1 is temporarily retreated from the loading position P to the start position P0, but this is not limited to this particular form, and the forklift 1 may also be temporarily retreated to a position away from the loading position P.

[0164] In addition, in the above embodiment, the holding pallet 11A is placed on the loading platform 18 of the truck 17, but this is not limited to this particular form, and the holding pallet 11A may be placed, for example, on a truck berth or a designated floor surface, etc.

[0165] Furthermore, in the above embodiment, the cargo placement area 18a on the cargo bed 18 is detected by the camera 21 or the side camera 51 and the front camera 52, but the cargo placement area detection unit that detects the cargo placement area 18a is not limited to a camera, and a laser sensor, an ultrasonic sensor, an optical sensor, etc. may also be used.

[0166] In the above embodiment, the forklift 1 is a reach forklift, but the forklift 1 may be a counter-load forklift. In this case, when placing a load on the holding pallet 11A, the forklift 1 is driven forward to place the holding pallet 11A at the load placement location 18a.

[0167] Furthermore, in the above embodiment, the forklift 1 is equipped with the side shift cylinder 15, but the present invention is also applicable to a forklift that is not equipped with the side shift cylinder 15. [Explanation of symbols]

[0168] 1... forklift, 11... pallet, 12... fork, 15... side shift cylinder, 17... truck, 18... loading platform, 18a... loading location, 20, 20A, 20B... loading control device, 21... camera (loading location detection unit), 31, 31B... loading platform position and orientation calculation unit (position and orientation calculation unit), 32... loading possibility determination unit, 33... self-position estimation unit (approach control unit, re-approach control unit), 34... route generation unit (approach control unit), 35... guidance control unit (approach control unit), 36... approach determination unit, 37, 37A...re-route generation unit (re-approach control unit), 38, 38A...re-guidance control unit (re-approach control unit), 39...re-approach determination unit, 40...number of times determination unit, 41...cargo placement control unit, 42...abnormal stop control unit, 45...evacuation control unit (re-approach control unit), 51...side camera (first detection unit, cargo placement location detection unit), 52...front camera (second detection unit, cargo placement location detection unit), P0...starting position, P...cargo placement position, J...specified amount, θx...pitch angle threshold, θy...roll angle threshold, θz...yaw angle threshold.

Claims

1. A cargo handling control device that moves a forklift holding a pallet by forks from a start position toward a cargo placement location to place the pallet, a load placement location detection unit that detects the load placement location; a position and orientation calculation unit that calculates a position and orientation of the load placement location relative to the forklift based on detection data from the load placement location detection unit; an approach control unit that controls the forklift to approach a load placement position in front of the load placement position based on the position and orientation of the load placement position relative to the forklift calculated by the position and orientation calculation unit when the forklift is at the start position; an approach determination unit that determines whether the forklift has successfully approached the loading position based on the position and orientation of the loading location relative to the forklift calculated by the position and orientation calculation unit when the forklift reaches the loading position; a placement control unit that controls the forklift to place the pallet at the placement location when the approach determination unit determines that the forklift has successfully approached the placement location; a re-approach control unit that controls the forklift to re-approach the loading position based on the position and orientation of the loading position relative to the forklift calculated by the position and orientation calculation unit when the approach determination unit determines that the forklift has failed to approach the loading position; a placement possibility determination unit that determines whether there is a possibility that the pallet will be successfully placed at the placement location based on the position and orientation of the placement location relative to the forklift calculated by the position and orientation calculation unit; A cargo handling control device comprising: an abnormality stop control unit that controls the forklift to abnormally stop its travel when the cargo placement possibility determination unit determines that there is no possibility of successfully placing the pallet at the cargo placement location.

2. the load placement possibility determination unit determines whether there is a possibility that the pallet will be successfully placed at the load placement location based on the position and orientation of the load placement location relative to the forklift calculated by the position and orientation calculation unit when the forklift is at the start position; 2. The cargo handling control device according to claim 1, wherein when the cargo placement possibility determination unit determines that there is a possibility that the pallet will be successfully placed at the placement location, the approach control unit controls the forklift to approach the placement location based on the position and attitude of the placement location relative to the forklift calculated by the position and attitude calculation unit when the forklift is at the starting position.

3. 2. The cargo handling control device according to claim 1, wherein the cargo placement possibility determination unit determines that there is a possibility that the pallet will be successfully placed at the cargo placement location when the pitch angle of the forklift relative to the cargo placement location is equal to or less than a predetermined pitch angle threshold and the roll angle of the forklift relative to the cargo placement location is equal to or less than a predetermined roll angle threshold, and determines that there is no possibility that the pallet will be successfully placed at the cargo placement location when the pitch angle of the forklift relative to the cargo placement location is greater than the pitch angle threshold or when the roll angle of the forklift relative to the cargo placement location is greater than the roll angle threshold.

4. The forklift truck has a side shift cylinder that moves the forks in the left and right directions of the forklift truck, 2. The cargo handling control device according to claim 1, wherein the approach determination unit determines that the approach of the forklift to the loading location is successful when the amount of lateral deviation of the forklift from the loading location is less than a predetermined specified amount and the yaw angle of the forklift with respect to the loading location is less than a predetermined yaw angle threshold, and determines that the approach of the forklift to the loading location is unsuccessful when the amount of lateral deviation of the forklift from the loading location is greater than the specified amount or the yaw angle of the forklift with respect to the loading location is greater than the yaw angle threshold.

5. a re-approach determination unit that determines whether the forklift has successfully re-approached the loading position based on the position and orientation of the loading position relative to the forklift calculated by the position and orientation calculation unit when the forklift reaches the loading position again, the re-approach control unit controls the forklift to re-approach the load placement position based on the position and attitude of the load placement location relative to the forklift calculated by the position and attitude calculation unit when the re-approach determination unit determines that the forklift has failed in its re-approach to the load placement position; The cargo handling control device described in claim 1, wherein the cargo placement control unit controls the forklift to place the pallet at the cargo placement location when the re-approach determination unit determines that the forklift's re-approach to the cargo placement location has been successful.

6. a number determination unit that, when the re-approach determination unit determines that the forklift has failed in its re-approach to the loading position, determines whether the number of times the forklift has re-approached the loading position has reached a predetermined upper limit; The load handling control device according to claim 5, wherein the abnormal stop control unit controls the forklift to abnormally stop the forklift's movement when the loading possibility determination unit determines that there is no possibility of successfully loading the pallet at the loading location, or when the number determination unit determines that the number of times the forklift has re-approached the loading location has reached the upper limit value.

7. 2. The cargo handling control device according to claim 1, wherein, when it is determined that the forklift's approach to the loading position has failed, the re-approach control unit controls the forklift to temporarily retreat to the loading position and then re-approach the loading position based on the position and attitude of the loading location relative to the forklift calculated by the position and attitude calculation unit when the forklift is at the loading position.

8. 2. The cargo handling control device according to claim 1, wherein, when it is determined that the forklift's approach to the loading position has failed, the re-approach control unit controls the forklift to temporarily retreat to the loading position, and then controls the forklift to re-approach the loading position based on the position and attitude of the loading location relative to the forklift calculated by the position and attitude calculation unit.

9. 9. The cargo handling control device according to claim 8, wherein the re-approach control unit controls the forklift to temporarily retreat to the start position relative to the loading position, and then controls the forklift to re-approach the loading position based on the position and attitude of the loading location relative to the forklift calculated by the position and attitude calculation unit when the forklift is at the start position.

10. 2. The cargo handling control device according to claim 1, wherein the cargo placement location detection unit detects the cargo placement location while the forklift is facing forward toward the cargo placement location.

11. The load placement location detection unit includes a first detection unit that detects the load placement location when the forklift is facing sideways toward the load placement location, and a second detection unit that detects the load placement location when the forklift is facing frontward toward the load placement location, 2. The cargo handling control device according to claim 1, wherein the position and attitude calculation unit calculates the position and attitude of the cargo placement location relative to the forklift based on the detection data of the first detection unit when the forklift is at the start position, and calculates the position and attitude of the cargo placement location relative to the forklift based on the detection data of the second detection unit when the forklift is at the cargo placement location.

12. 2. A cargo handling control device according to claim 1, wherein the cargo placement location is a location provided on the bed of a truck.

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