Travel control device

Abstract

To provide a travel control device capable of making a forklift travel to a target position by detecting the front face of a pallet even if a space on the front face side of the pallet is narrow.SOLUTION: The travel control device 20 includes the camera 21, the laser sensor 22, and the detection processing unit 32 that detect a front surface 15a of the pallet 15 just beside the forklift 1, the position and posture calculation unit 33 that calculates a position and a posture of the pallet 15 with respect to the forklift 1 on the basis of the front surface 15a of the pallet 15, the route generation unit 34 that generates a travel route to a target position on the basis of the position and the posture of the pallet 15 with respect to the forklift 1, and the travel control unit 35 that controls the travel motor 7 such that the forklift 1 travels along the travel route. The route generation unit 34 generates a travel route in which the forklift 1 moves backward, then moves forward toward the target position, and turns.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] For example, Patent Document 1 describes a technology in which an image of an object located in front of a forklift is captured by an imaging unit, and the forklift is driven toward the object based on image data of the object to perform cargo handling. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-58985 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when a pallet is being held by the forks of a forklift, if there is a lot of space in front of the pallet, the front of the pallet can be detected by photographing the pallet located in front of the forklift as in the above-mentioned conventional technology, and the forklift can then travel forward to the target position, the pallet. However, if the space in front of the pallet is narrow, it may not be possible to detect the front of the pallet. Also, even if the front of the pallet can be detected, it may not be possible to travel the forklift to the pallet.

[0005] An object of the present invention is to provide a travel control device that can detect the front of a pallet and allow a forklift to travel to a target position even if the space in front of the pallet is narrow. [Means for solving the problem]

[0006] One aspect of the present invention is a travel control device that controls a forklift to travel from a state in which the forklift is positioned on the front side of a pallet to a target position relative to the pallet, and includes: a drive unit that drives the forklift; a pallet detection unit that detects the front side of the pallet; a position and attitude calculation unit that calculates the position and attitude of the pallet relative to the forklift based on the front side of the pallet detected by the pallet detection unit; a path generation unit that generates a travel path to the target position based on the position and attitude of the pallet relative to the forklift calculated by the position and attitude calculation unit; and a travel control unit that controls the drive unit to travel the forklift according to the travel path generated by the path generation unit, wherein the pallet detection unit detects the front side of the pallet in the lateral direction of the forklift when the forklift is positioned relative to the pallet so that the fore-and-aft direction of the forklift intersects with the fore-and-aft direction of the pallet, and the path generation unit generates a travel path that causes the forklift to turn toward the target position.

[0007] In such a travel control device, the front surface of the pallet is first detected, and the position and orientation of the pallet relative to the forklift are calculated based on the front surface of the pallet. A travel route to a target position relative to the pallet is then generated based on the position and orientation of the pallet relative to the forklift, and the forklift travels along this travel route. The forklift is positioned relative to the pallet so that the fore-and-aft direction of the forklift intersects with the fore-and-aft direction of the pallet, and the front surface of the pallet is detected in the lateral direction of the forklift. Therefore, even if the space in front of the pallet is narrow, the front surface of the pallet can be detected. A travel route is then generated that allows the forklift to turn toward the target position. Therefore, even if the space in front of the pallet is narrow, the forklift can be traveled to the target position relative to the pallet.

[0008] The path generator may generate a travel path that causes the forklift to move forward toward the target position and then turn around. In this configuration, the forklift can be made to travel smoothly to the target position relative to the pallet.

[0009] The pallet detection unit may include a laser sensor that detects the distance to the front of the pallet by emitting a laser laterally from the forklift toward the front of the pallet and receiving the reflected laser light to acquire point cloud data, and a camera that captures an image of the front of the pallet laterally from the forklift to acquire image data. In this configuration, by using the laser sensor and camera to detect the front of the pallet, detection of the front of the pallet can be achieved with simple processing.

[0010] The pallet detection unit may detect the front surface of the pallet by recognizing the pallet based on image data acquired by the camera and extracting point cloud data corresponding to the recognized pallet from the point cloud data acquired by the laser sensor. In this configuration, the pallet is recognized based on image data acquired by the camera. Then, point cloud data corresponding to the recognized pallet is extracted from the point cloud data acquired by the laser sensor. Image data from the camera has a higher resolution than point cloud data from the laser sensor. This increases the accuracy of pallet recognition. Therefore, the front surface of the pallet can be detected with high accuracy.

[0011] A frame extending in the vertical direction of the forklift is fixed to the body of the forklift, and the laser sensor and camera may be attached to the frame so that their mounting height is adjustable. In this configuration, by changing the mounting height of the laser sensor and camera relative to the frame in accordance with the height position of the pallet, it is possible to detect the front of the pallet with even higher accuracy.

[0012] The pallet detection unit may detect the front face of the pallet directly to the side of the forklift, and the path generation unit may generate a travel path that causes the forklift to back up and then turn toward the target position. In this configuration, by detecting the front face of the pallet directly to the side of the forklift, the front face of the pallet can be detected with even greater accuracy. Furthermore, by generating a travel path that causes the forklift to back up and then turn toward the target position, the forklift can be driven to the target position relative to the pallet regardless of the installation location or orientation of the pallet detection unit.

[0013] The pallet detection unit may detect the front of the pallet from directly to the side of the forklift and diagonally forward. In this configuration, by generating a travel path that allows the forklift to continue moving forward toward the target position and then turn, there is no need to reverse the forklift after the front of the pallet is detected. This shortens the distance the forklift must travel to the target position, thereby reducing work time.

[0014] The travel control device may further include a stop control unit that controls the drive unit to stop the forklift traveling in a direction intersecting the front-to-rear direction of the pallet at a position where the front face of the pallet can be detected, and the pallet detection unit may detect the front face of the pallet in the lateral direction of the forklift when the forklift is stopped. In this configuration, by detecting the front face of the pallet when the forklift is stopped, the pallet does not shift relative to the forklift, and the front face of the pallet can be detected with even higher accuracy. [Effects of the Invention]

[0015] According to the present invention, even if the space in front of the pallet is narrow, the front of the pallet can be detected and the forklift can be driven to the target position. [Brief explanation of the drawings]

[0016] [Figure 1]1 is a side view showing a forklift equipped with a travel control device according to an embodiment of the present invention. [Figure 2] 1 is a block diagram showing the configuration of a driving control device according to an embodiment of the present invention; [Figure 3] 2A and 2B are a plan view, a front view, and a side view showing the front part of the traveling device shown in FIG. 1. [Figure 4] 3 is a flowchart showing the procedure of a pallet detection process executed by a detection processing unit shown in FIG. 2. [Figure 5] 3 is a flowchart showing the procedure of a position and orientation calculation process executed by a position and orientation calculation unit shown in FIG. 2. [Figure 6] 3 is a plan view schematically showing the operation of the driving control device shown in FIG. 2.

[0023] FIG. [Figure 7] FIG. 1 is a plan view showing a schematic view of the environment around a truck on which a pallet is placed. [Figure 8] 7 is a plan view schematically showing a modified example of the operation of the driving control device shown in FIG. 6.

[0033] FIG. [Figure 9] 7 is a plan view schematically showing another modified example of the operation of the driving control device shown in FIG. 6.

[0033] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] 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.

[0018] Fig. 1 is a side view showing a forklift equipped with a travel control device according to one embodiment of the present invention. In Fig. 1, the forklift 1 includes a travel device 2 and a loading device 3 disposed in front of the travel device 2 for loading and unloading.

[0019] The traveling device 2 has a body 4, a pair of left and right front wheels 5 which are drive wheels located at the front of the body 4, a pair of left and right rear wheels 6 which are steered wheels located at the rear of the body 4, a pair of left and right traveling motors 7 which independently rotate the front wheels 5, and a loading motor 8 which rotates a hydraulic pump (not shown). The traveling motors 7 are the drive units that cause the forklift 1 to travel.

[0020] The vehicle body 4 has a pair of left and right front pillars 10 and a pair of left and right rear pillars 11. The rear pillars 11 are disposed rearward of the front pillars 10. Head guards 12 are connected to the upper portions of the front pillars 10 and rear pillars 11.

[0021] The cargo handling device 3 has a mast 13 erected at the front end of the vehicle body 4, a pair of left and right forks 16 that are attached to the mast 13 via lift brackets 14 so that they can be raised and lowered and that hold a pallet 15, a lift cylinder 17 that raises and lowers the forks 16, and a tilt cylinder 18 that tilts the forks 16 via the mast 13. The lift cylinder 17 and tilt cylinder 18 are driven by hydraulic oil from the hydraulic pump (described above).

[0022] The pallet 15 is a loading platform on which cargo M is placed. The pallet 15 is, for example, a flat pallet. The pallet 15 has a rectangular shape in a plan view. The pallet 15 has a pair of fork holes 19 into which each fork 16 is inserted. The fork holes 19 extend from the front surface 15a to the rear surface 15b of the pallet 15.

[0023] Fig. 2 is a block diagram showing the configuration of a travel control device according to one embodiment of the present invention. In Fig. 2, travel control device 20 of this embodiment is a device that controls forklift 1 to automatically travel from a state in which forklift 1 is positioned on the front surface 15a side of pallet 15 (see Fig. 6) toward a target position relative to pallet 15.

[0024] The travel control device 20 is mounted on the forklift 1. The travel control device 20 includes a camera 21, a laser sensor 22, a controller 23, and the travel motor 7.

[0025] The camera 21 captures an image of the front surface 15a of the pallet 15 to obtain image data. The camera 21 captures an image of the front surface 15a of the pallet 15 in the lateral direction of the forklift 1. As the camera 21, for example, a monocular camera or the like is used.

[0026] The laser sensor 22 emits a laser toward the front surface 15a of the pallet 15 and receives the reflected laser light to detect the distance to the front surface 15a of the pallet 15 and acquire point cloud data. The point cloud is a collection of laser reflection points. The laser sensor 22 emits a laser toward the front surface 15a of the pallet 15 in the lateral direction of the forklift 1. For example, a 2D or 3D LIDAR or a laser range finder may be used as the laser sensor 22.

[0027] As shown in Figures 1 and 3, the camera 21 and the laser sensor 22 are attached to a frame 24 that extends in the up-down direction (Z direction) of the forklift 1. The frame 24 is attached to the upper part of the front pillar 10 via frames 25 and 26. The frames 24 to 26 are disposed on the left side of the forklift 1. The frame 25 extends from the upper left part of the front pillar 10 outward in the vehicle width direction (Y direction). The frame 26 extends from the frame 25 to the front side in the fore-and-aft direction (X direction). The frame 24 extends directly downward from the frame 26. The frames 24 to 26 are made of, for example, aluminum or the like.

[0028] The camera 21 and the laser sensor 22 are attached to the frame 24 side by side in the vertical direction. Here, the camera 21 is arranged on the upper side, and the laser sensor 22 is arranged on the lower side. However, the arrangement positions of the camera 21 and the laser sensor 22 may be reversed.

[0029] The camera 21 is attached to the frame 24 via a mounting bracket 27 so that its mounting height position is adjustable. The laser sensor 22 is attached to the frame 24 via a mounting bracket 28 so that its mounting height position is adjustable. The mounting brackets 27, 28 are slidable in the vertical direction relative to the frame 24. Therefore, the mounting height positions of the camera 21 and the laser sensor 22 are adjustable relative to the frame 24. The mounting brackets 27, 28 are fixed to the frame 24, for example, with bolts and nuts (not shown).

[0030] The camera 21 and the laser sensor 22 are attached to the frame 24 via mounting brackets 27, 28 so that their front faces directly to the side of the forklift 1. Therefore, the camera 21 captures an image of the front surface 15a of the pallet 15 directly to the side of the forklift 1. The laser sensor 22 emits a laser beam directly to the side of the forklift 1, directed toward the front surface 15a of the pallet 15. The imaging range of the camera 21 and the laser irradiation range of the laser sensor 22 correspond to the detection range S of the front surface 15a of the pallet 15 (see FIG. 6(a)).

[0031] The controller 23 is configured with a CPU, RAM, ROM, an input / output interface, etc. The controller 23 has a detection position determination unit 30, a stop control unit 31, a detection processing unit 32, a position and orientation calculation unit 33, a path generation unit 34, and a travel control unit 35.

[0032] The detection position determination unit 30 determines whether the forklift 1 has reached the detection position based on image data acquired by the camera 21 while the forklift 1 is traveling in a direction perpendicular to the front-to-rear direction of the pallet 15. The detection position is a position where the front surface 15a of the pallet 15 can be detected using the camera 21 and the laser sensor 22. Specifically, the detection position is a position where the camera 21 and the laser sensor 22 face the front surface 15a of the pallet 15 (see FIG. 6(a)).

[0033] The stop control unit 31 controls the traveling motor 7 to stop the traveling of the forklift 1 when the detection position determination unit 30 determines that the forklift 1 has reached the detection position.

[0034] The detection processing unit 32 cooperates with the camera 21 and the laser sensor 22 to form a pallet detection unit that detects the front surface 15a of the pallet 15 in the lateral direction of the forklift 1. The detection processing unit 32 performs processing to detect the front surface 15a of the pallet 15 in the lateral direction of the forklift 1 when the forklift 1 is positioned relative to the pallet 15 so that the front-to-back direction of the forklift 1 is perpendicular to the front-to-back direction of the pallet 15. The lateral direction of the forklift 1 is a direction that intersects with the front-to-back direction of the forklift 1 in a horizontal plane.

[0035] Fig. 4 is a flowchart showing the procedure of the pallet detection process executed by the detection processing unit 32. In Fig. 4, the detection processing unit 32 first acquires point cloud data by the laser sensor 22 (step S101).

[0036] The detection processing unit 32 also acquires image data from the camera 21 (step S102). The detection processing unit 32 then recognizes the pallet 15 based on the image data acquired in step S102 (step S103). At this time, the detection processing unit 32 recognizes the pallet 15 by, for example, an image processing technique using deep learning.

[0037] Then, the detection processing unit 32 extracts point cloud data corresponding to the pallet 15 recognized in step S103 from the point cloud data acquired in step S101 (step S104). This detects the front surface 15a of the pallet 15. Next, the detection processing unit 32 performs a filtering process on the point cloud data extracted in step S104 (step S105).

[0038] Returning to FIG. 2, the position and orientation calculation unit 33 calculates the position and orientation of the pallet 15 relative to the forklift 1 based on the front surface 15 a of the pallet 15 detected by the detection processing unit 32 .

[0039] Fig. 5 is a flowchart showing the procedure of the position and orientation calculation process executed by the position and orientation calculation unit 33. In Fig. 5, the position and orientation calculation unit 33 first acquires point cloud data that has been subjected to filtering processing by the detection processing unit 32 (step S111).

[0040] Next, the position and orientation calculation unit 33 calculates a plane equation of the front surface 15a of the pallet 15 using a robust estimation method such as RANSAC (Random Sample Consensus) or the least squares method (step S112).

[0041] Next, the position and orientation calculation unit 33 calculates the position and orientation of the pallet 15 relative to the forklift 1 by a known method using a plane equation for the front surface 15a of the pallet 15 (step S113). The position of the pallet 15 relative to the forklift 1 is the three-dimensional position coordinates of the center of the front surface 15a of the pallet 15 relative to the forklift 1. The orientation of the pallet 15 relative to the forklift 1 is the yaw angle, pitch angle, and roll angle of the pallet 15 relative to the forklift 1.

[0042] 2, the path generation unit 34 generates a travel path to a target position for the pallet 15 based on the position and orientation of the pallet 15 relative to the forklift 1 calculated by the position and orientation calculation unit 33. The target position is a position where the forks 16 of the forklift 1 are inserted into the fork holes 19 of the pallet 15.

[0043] The path generating unit 34 generates a travel path that causes the forklift 1 to turn toward the target position. Specifically, the path generating unit 34 generates a travel path R that causes the forklift 1 to move backward in a straight line for a predetermined distance, then move forward toward the target position and turn (see FIG. 6(b)). The predetermined distance is a distance that allows the forklift 1 to turn. In this case, the travel path R is generated using, for example, a clothoid curve or the like.

[0044] The travel control unit 35 controls the travel motor 7 so that the forklift 1 travels along the travel route generated by the route generation unit 34.

[0045] As described above, as shown in Figure 6, the pallet 15 is placed on the loading platform 40a of the truck 40. The pallet 15 is arranged so that the front surface 15a faces the right side of the truck 40. In this state, when the forks 16 of the forklift 1 are to hold the pallet 15, i.e., to pick up the load, the forklift 1 automatically moves backward in a straight line along the front-to-rear direction of the truck 40 on the right side of the truck 40.

[0046] Then, as shown in Fig. 6(a), when the forklift 1 reaches the detection position, the forklift 1 stops temporarily. In this state, the camera 21 captures an image of the front surface 15a of the pallet 15 to obtain image data, and the laser sensor 22 irradiates the front surface 15a of the pallet 15 with a laser to obtain point cloud data. The front surface 15a of the pallet 15 is then detected based on the image data and the point cloud data, and the position and orientation of the pallet 15 relative to the forklift 1 are calculated. Note that the camera 21 and the laser sensor 22 are omitted from Fig. 6 for convenience.

[0047] Then, as shown in Fig. 6(b), a travel route R is generated in which the forklift 1 moves backward in a straight line a predetermined distance, then moves forward toward the target position and turns left. Then, as shown in Fig. 6(c), the forklift 1 travels from the detection position to the target position along the travel route R. Specifically, the forklift 1 moves backward in a straight line a predetermined distance from the detection position, then moves forward and turns left to reach the target position.

[0048] Thereafter, with the forks 16 of the forklift 1 inserted into the fork holes 19 of the pallet 15, the forks 16 are raised by the lift cylinders 17, so that the pallet 15 is held by the forks 16. Then, the forklift 1 transports the pallet 15 to the designated location.

[0049] Incidentally, as shown in Figure 7(a), in a location where there is a large space to the right of the truck 40, the approach distance of the forklift 1 can be made longer in the lateral direction of the truck 40. Therefore, even if the camera 21 and the laser sensor 22 are facing forward of the forklift 1, the camera 21 and the laser sensor 22 can detect the front surface 15a of the pallet 15, and the forklift 1 can approach the pallet 15 by moving forward. Note that the camera 21 and the laser sensor 22 are omitted from Figure 7 for convenience.

[0050] However, as shown in Figure 7(b), if an object 41 such as another truck, a wall, a shelf, or luggage is placed to the right of the truck 40, the space to the right of the truck 40 becomes narrower, and the approach distance of the forklift 1 cannot be increased laterally from the truck 40. Therefore, if the camera 21 and the laser sensor 22 are facing forward of the forklift 1, the camera 21 and the laser sensor 22 may not be able to detect the front surface 15a of the pallet 15 depending on the distance between the truck 40 and the object 41. Even if the front surface 15a of the pallet 15 can be detected, the forklift 1 cannot travel forward to the target position of the pallet 15.

[0051] To address this issue, in this embodiment, the front surface 15a of the pallet 15 is detected in the lateral direction of the forklift 1 when the forklift 1 is positioned relative to the pallet 15 so that the fore-and-aft direction of the forklift 1 intersects with the fore-and-aft direction of the pallet 15. Therefore, even if the space on the front surface 15a side of the pallet 15 is narrow, the front surface 15a of the pallet 15 can be detected. Then, a travel path R is generated such that the forklift 1 turns toward the target position. Therefore, even if the space on the front surface 15a side of the pallet 15 is narrow, the forklift 1 can travel to the target position relative to the pallet 15. As described above, even if the approach distance of the forklift 1 along the fore-and-aft direction of the pallet 15 is short, the forklift 1 can pick up the load.

[0052] Furthermore, in this embodiment, the forklift 1 can be caused to travel smoothly to the target position relative to the pallet 15 by generating a travel route R such that the forklift 1 moves forward and turns toward the target position.

[0053] Furthermore, in this embodiment, by using the camera 21 and the laser sensor 22 to detect the front surface 15a of the pallet 15, the detection of the front surface 15a of the pallet 15 can be realized by simple processing.

[0054] In this embodiment, the pallet 15 is recognized based on image data acquired by the camera 21. Then, point cloud data corresponding to the recognized pallet 15 is extracted from the point cloud data acquired by the laser sensor 22. The image data from the camera 21 has a higher resolution than the point cloud data from the laser sensor 22. This increases the recognition accuracy of the pallet 15. Therefore, the front surface 15a of the pallet 15 can be detected with high accuracy.

[0055] In addition, in this embodiment, by changing the mounting height positions of the camera 21 and the laser sensor 22 relative to the frame 24 in accordance with the height position of the pallet 15, the front surface 15a of the pallet 15 can be detected with even higher accuracy.

[0056] Furthermore, in this embodiment, the front surface 15a of the pallet 15 can be detected with higher accuracy by detecting the front surface 15a of the pallet 15 directly to the side of the forklift 1. Furthermore, by generating a travel route R in which the forklift 1 moves backward and then turns toward the target position, the forklift 1 can be made to travel to the target position relative to the pallet 15 regardless of the mounting locations and orientations of the camera 21 and the laser sensor 22.

[0057] In addition, in this embodiment, by detecting the front surface 15a of the pallet 15 when the forklift 1 is stopped, the pallet 15 does not shift relative to the forklift 1, and therefore the front surface 15a of the pallet 15 can be detected with even higher accuracy.

[0058] The present invention is not limited to the above embodiment. For example, in the above embodiment, the front surface 15a of the pallet 15 is detected directly to the side of the forklift 1, but the present invention is not particularly limited to such an embodiment.

[0059] Figure 8 is a plan view schematically showing a modified example of the operation of the travel control device shown in Figure 6. As shown in Figure 8(a), the camera 21 captures an image of the front surface 15a of the pallet 15 diagonally forward from the side of the forklift 1, and the laser sensor 22 irradiates a laser beam toward the front surface 15a of the pallet 15 diagonally forward from the side of the forklift 1, thereby detecting the front surface 15a of the pallet 15 diagonally forward from the side of the forklift 1.

[0060] Then, as shown in Fig. 8(b), a travel route R is generated such that the forklift 1 moves forward from the detection position toward the target position and then turns. Then, as shown in Fig. 8(c), the forklift 1 travels to the target position according to the travel route R.

[0061] In this modified example, by generating a travel route R such that the forklift 1 moves forward toward the target position and then turns, there is no need to move the forklift 1 backward after detecting the front surface 15a of the pallet 15. Therefore, the travel distance of the forklift 1 to the target position is shortened, and the operation time can be reduced.

[0062] Alternatively, the camera 21 may capture an image of the front surface 15a of the pallet 15 obliquely rearward from directly beside the forklift 1, and the laser sensor 22 may irradiate a laser beam toward the front surface 15a of the pallet 15 obliquely rearward from directly beside the forklift 1, thereby detecting the front surface 15a of the pallet 15 obliquely rearward from directly beside the forklift 1. In this case, a travel route R may be generated such that the forklift 1 moves backward, then moves forward toward the target position and turns.

[0063] Furthermore, in the above embodiment, when the forklift 1 picks up an item, the front surface 15a of the pallet 15 is detected, and based on the detection results, the forklift 1 travels to a target position where the forks 16 are inserted into the fork holes 19 of the pallet 15. However, the present invention is not limited to such an embodiment. For example, when placing the pallet 15 held by the forks 16 at a specified location, i.e., when placing the item, the front surface 15a of the existing pallet 15 may be detected, and based on the detection results, the forklift 1 may travel to a target position adjacent to the existing pallet 15.

[0064] Fig. 9 is a plan view schematically showing another modified example of the operation of the travel control device shown in Fig. 6. In Fig. 9, a pallet 15A for loading is held on the forks 16 of the forklift 1. An existing pallet 15 is placed on the loading platform 40a of the truck 40.

[0065] As shown in Fig. 9(a), the camera 21 and laser sensor 22 detect the front surface 15a of the pallet 15 directly to the side of the forklift 1. Then, as shown in Fig. 9(b), a travel route R is generated such that the forklift 1 moves backward straight from the detection position, then moves forward toward a position L to the left of the existing pallet 15 and turns. The position L to the left of the pallet 15 is the target position for the pallet 15. Then, as shown in Fig. 9(c), the forklift 1 travels along the travel route R to the target position.

[0066] Thereafter, the forks 16 are lowered by the lift cylinders 17, and the pallet 15A held by the forks 16 is placed on the loading platform 40a of the truck 40 to the left of the existing pallet 15.

[0067] In this modified example, even if the space on the front side 15a of the existing pallet 15 is narrow, the front side 15a of the pallet 15 is detected, and the forklift 1 travels to the target position relative to the pallet 15. As described above, even if the approach distance of the forklift 1 along the front-to-rear direction of the pallet 15 is short, the forklift 1 can place the load.

[0068] Furthermore, in the above embodiment, the camera 21 and laser sensor 22 detect the front surface 15a of the pallet 15 in the lateral direction of the forklift 1 when the forklift 1 is positioned relative to the pallet 15 so that the fore-and-aft direction of the forklift 1 is perpendicular to the fore-and-aft direction of the pallet 15, but this is not particularly limited to such an embodiment. The camera 21 and laser sensor 22 may detect the front surface 15a of the pallet 15 in the lateral direction of the forklift 1 when the forklift 1 is positioned relative to the pallet 15 so that the fore-and-aft direction of the forklift 1 is not perpendicular to the fore-and-aft direction of the pallet 15. In other words, the camera 21 and laser sensor 22 may detect the front surface 15a of the pallet 15 in the lateral direction of the forklift 1 when the forklift 1 is positioned relative to the pallet 15 so that the fore-and-aft direction of the forklift 1 diagonally intersects the fore-and-aft direction of the pallet 15.

[0069] In the above embodiment, a travel route R is generated in which the forklift 1 moves backward and then moves forward toward the target position and then turns, and a travel route R in which the forklift 1 moves forward toward the target position and then turns without moving backward, but the present invention is not limited to such a form. For example, a travel route R in which the forklift 1 turns toward the target position without moving forward (so-called turning on the spot) may be generated, or a travel route R in which the forklift 1 moves backward and then turns toward the target position may be generated.

[0070] Furthermore, in the above embodiment, the forklift 1 moves backward in a straight line to enter the detection position, but the present invention is not limited to this particular form, and the forklift 1 may move forward in a straight line to enter the detection position.

[0071] Furthermore, in the above embodiment, the forklift 1 moves backward and stops at the detection position, and in this state the camera 21 and laser sensor 22 detect the front surface 15a of the pallet 15. However, this is not limited to this particular form, and the forklift 1 may move backward at a slow or gentle speed and the camera 21 and laser sensor 22 may detect the front surface 15a of the pallet 15.

[0072] Furthermore, in the above embodiment, whether the forklift 1 has reached the detection position is determined based on image data acquired by the camera 21, but this is not limited to a particular form, and for example, whether the forklift 1 has reached the detection position may be determined based on point cloud data acquired by the laser sensor 22.

[0073] Furthermore, in the above embodiment, the forklift 1 automatically travels to the detection position, but the present invention is not limited to this particular configuration, and the forklift 1 may be manually driven by the driver to travel to the detection position.

[0074] In addition, in the above embodiment, the camera 21 and the laser sensor 22 are attached to the frame 24 connected to the front pillar 10 via the frames 25 and 26 so that the attachment height position is adjustable, but this is not particularly limited to such a configuration. The camera 21 and the laser sensor 22 may be attached directly to an existing member of the vehicle body 4, such as the front pillar 10. In this case, the frames 24 to 26 are not required, and therefore the number of parts does not need to be increased.

[0075] Furthermore, in the above embodiment, the camera 21 and the laser sensor 22 are arranged side by side in the vertical direction, but this is not particularly limited to this configuration, and the camera 21 and the laser sensor 22 may also be arranged side by side in the front-to-back direction.

[0076] Furthermore, in the above embodiment, the camera 21 and the laser sensor 22 are arranged only on the left side of the forklift 1, but this is not a particular limitation. The camera 21 and the laser sensor 22 may be arranged only on the right side of the forklift 1, or on both the left and right sides of the forklift 1. By arranging the camera 21 and the laser sensor 22 on both the left and right sides of the forklift 1, even if trucks 40 with pallets 15 placed on their loading platforms 40a are parked on both the left and right sides of the forklift 1, the front faces 15a of both pallets 15 can be detected.

[0077] In addition, in the above embodiment, the front surface 15a of the pallet 15 is detected using both the camera 21 and the laser sensor 22, but this is not particularly limited to this form, and for example, the front surface 15a of the pallet 15 may be detected using only either the camera 21 or the laser sensor 22.

[0078] Furthermore, in the above embodiment, the pallet 15 is placed on the loading platform 40a of the truck 40, but the location where the pallet 15 is placed is not limited to the truck 40, and may be a loading platform, shelf, or floor surface other than a vehicle. [Explanation of symbols]

[0079] 1...forklift, 4...vehicle body, 7...travel motor (drive unit), 15...pallet, 15a...front, 16...fork, 21...camera (pallet detection unit), 22...laser sensor (pallet detection unit), 24...frame, 31...stop control unit, 32...detection processing unit (pallet detection unit), 33...position and orientation calculation unit, 34...path generation unit, 35...travel control unit, R...travel path.

Claims

1. A travel control device that controls a forklift to travel from a state in which the forklift is positioned on the front side of a pallet to a target position relative to the pallet, a drive unit that drives the forklift; a pallet detection unit that detects the front surface of the pallet; a position and orientation calculation unit that calculates the position and orientation of the pallet relative to the forklift based on the front surface of the pallet detected by the pallet detection unit; a route generation unit that generates a travel route to the target position based on the position and orientation of the pallet relative to the forklift calculated by the position and orientation calculation unit; a travel control unit that controls the drive unit so as to cause the forklift to travel along the travel route generated by the route generation unit, the pallet detection unit detects the front surface of the pallet directly to the side of the forklift when the forklift is positioned relative to the pallet such that the front-rear direction of the forklift intersects with the front-rear direction of the pallet; The route generation unit generates the travel route such that the forklift moves backward, then forward toward the target position and turns.

2. 2. The driving control device according to claim 1, wherein the pallet detection unit includes a laser sensor that detects the distance to the front of the pallet by irradiating a laser directly beside the forklift toward the front of the pallet and receiving the reflected light of the laser to acquire point cloud data, and a camera that captures an image of the front of the pallet directly beside the forklift to acquire image data.

3. 3. A driving control device as described in claim 2, wherein the pallet detection unit recognizes the pallet based on image data acquired by the camera, and detects the front of the pallet by extracting point cloud data corresponding to the recognized pallet from the point cloud data acquired by the laser sensor.

4. A frame extending in the vertical direction of the forklift is fixed to the body of the forklift, 3. The travel control device according to claim 2, wherein the laser sensor and the camera are attached to the frame so that their mounting height positions are adjustable.

5. a stop control unit that controls the drive unit so as to stop the forklift traveling in a direction intersecting the front-rear direction of the pallet at a position where the front surface of the pallet can be detected; The travel control device according to claim 1 , wherein the pallet detection unit detects the front surface of the pallet directly to the side of the forklift when the forklift is stopped.

Images