Conveyance robot and control method of the same

Abstract

To provide a conveyance robot capable of dropping an article to a drop position with high accuracy, and to provide a control method of the same.SOLUTION: A conveyance robot 1 can convey an article in a warehouse and includes: a sensor 50 capable of detecting a three-dimensional shape of an object; and a control unit 60 for controlling the conveyance operation of the conveyance robot 1. The control unit 60 identifies a structure 200 by the comparison of master data showing a three-dimensional shape of the structure 200 arranged at a local spot in the warehouse, and detection data showing the three dimensional shape of the structure 200 detected by the sensor 50.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a transport robot and a control method thereof. [Background technology]

[0002] For example, Patent Document 1 discloses a warehouse system. In this warehouse system, multiple carts are used to transport trays storing items from storage shelves on which the trays are arranged to an order preparation station for preparing the transported goods. In such a warehouse system, if the accuracy in dropping the trays from the carts to the drop positions is low, subsequent processing will be hindered. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 189110 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a transport robot and a control method thereof that can drop an article at a drop position with high accuracy.

[0005] A transport robot according to one embodiment of the present invention is a transport robot capable of transporting items within a warehouse, and is equipped with a sensor capable of detecting the three-dimensional shape of an object, and a control unit that controls the transport operation of the transport robot, and the control unit identifies the structure by comparing master data indicating the three-dimensional shape of a structure located locally within the warehouse with detection data indicating the three-dimensional shape of the structure detected by the sensor.

[0006] In a transport robot according to one aspect of the present invention, the structure is a structure including a drop position at which the item is dropped, and the control unit identifies the drop position of the structure by comparing the master data with the detection data.

[0007] In the transfer robot according to one aspect of the present invention, the control unit controls the travel of the transfer robot based on map data that shows, in two dimensions, the layout of structures within the warehouse.

[0008] In the transfer robot according to one aspect of the present invention, the sensor is a three-dimensional distance measuring sensor.

[0009] In the transfer robot according to one aspect of the present invention, the master data is generated by mapping using the three-dimensional distance measuring sensor.

[0010] In the transport robot according to one aspect of the present invention, the item is placed on a pallet.

[0011] In a transport robot according to one aspect of the present invention, the structure is a rack or a conveyor that defines a space for placing the pallet, or a narrow passage in the warehouse.

[0012] In the transport robot according to one aspect of the present invention, the transport robot is a forklift.

[0013] In a transport robot according to one aspect of the present invention, the sensor detects two-dimensional coordinate values ​​of the structure during movement as part of the detection data, and estimates its own position based on the master data and the detection data.

[0014] The transport robot according to one aspect of the present invention is configured to pick up the pallet by detecting the shape of the insertion opening of the pallet at a pick position based on a reference shape of the insertion opening of the pallet.

[0015] The transfer robot according to one aspect of the present invention is configured to drop a pallet based on the shape of the structure at the drop position.

[0016] The transfer robot according to one aspect of the present invention picks up a pallet from the floor and drops the pallet onto the structure on another floor, the transfer robot according to claim 1.

[0017] Another aspect of the present invention is a method for controlling a transfer robot configured to transfer articles in a warehouse according to any of the above.

[0018] Another aspect of the present invention is a system for controlling a transfer robot configured to transfer articles in a warehouse according to any of the above.

[0019] Another aspect of the present invention is a computer-readable medium that, when executed by a computer, includes instructions to cause a transfer robot to transfer articles in a warehouse according to any of the above.

[0020] A method for controlling a transfer robot according to another aspect of the present invention is a method for controlling a transfer robot capable of transferring articles in a warehouse, the method comprising identifying the structure by comparing master data indicating a three-dimensional shape of the structure arranged locally in the warehouse with detection data indicating a three-dimensional shape of the structure detected by the sensor.

[0021] A control program for a transfer robot according to another aspect of the present invention is a control program for a transfer robot capable of transferring articles in a warehouse, the program causing a computer to execute a step of identifying the drop position by comparing master data indicating a three-dimensional shape of the structure arranged locally in the warehouse with detection data indicating a three-dimensional shape of the structure detected by the sensor.

Brief Description of the Drawings

[0022] [Figure 1]FIG. 1 is a perspective view showing a warehouse system 100 in which a transport robot 1 according to an embodiment of the present invention is incorporated. [Diagram 2] 1 is a perspective view showing a schematic structure of a forklift 1 according to an embodiment of the present invention. [Diagram 3] 1 is a side view showing a schematic structure of a forklift 1 according to an embodiment of the present invention. [Figure 4] 1 is a plan view showing a schematic structure of a forklift 1 according to an embodiment of the present invention. [Diagram 5] 2 is a functional block diagram illustrating a schematic configuration of a management server 140. FIG. [Figure 6] 1 is a functional block diagram illustrating a schematic configuration of a forklift 1. FIG. [Figure 7] FIG. 7 is a schematic diagram of a map 72 showing the layout of structures in the warehouse system 100. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view that shows a warehouse system 100 in which a transport robot 1 according to an embodiment of the present invention is incorporated. An example of the warehouse system 100 is established by, for example, a plurality of floors in a building. In this example, as shown in FIG. 1, the warehouse system 100 has a lower floor 101 and a floor above the lower floor 101, i.e., an upper floor 102. A travel path for the transport robot 1 is formed on the floor surfaces of the lower floor 101 and the upper floor 102, respectively. As will be described later, the transport robot 1 is, for example, a forklift 1 that can autonomously travel on the floor surfaces of the lower floor 101 and the upper floor 102 by self-location estimation. In this example, a plurality of forklifts 1 are arranged on each of the lower floor 101 and the upper floor 102.

[0024] In the warehouse system 100, a temporary storage area 112 is defined in a predetermined area on the floor surface of the lower floor 101 and the upper floor 102, for temporarily storing a pallet 111 on whose surface one or more cardboard boxes 110 containing a large number of the same or different items are mounted. In this example, the pallet 111 is placed directly on the floor surface. One or more pallets 111 on which one or more cardboard boxes 110 are mounted are further stacked on the cardboard boxes 111 mounted on the pallet 111. In this example, a plurality of temporary storage areas 112 may be defined on the floor surface. Note that the pallet 111 is formed, for example, in a rectangular or square flat plate shape in a plan view. A pair of insertion holes for inserting the forks of the forklift 1 is formed on each of the four side surfaces of the pallet 111 connecting the front and back surfaces facing each other.

[0025] The warehouse system 100 has racks 120 arranged on the floor surfaces of the lower floor 101 and the upper floor 102. The rack 120 is, for example, a storage shelf for storing one or more cardboard boxes 110 described above while they are placed on a pallet 111. This rack 120 is a storage shelf for storing items on the pallet 111. The rack 120 has a plurality of rack units 122 formed by, for example, connecting metal frame members 121. The rack 120 is formed by stacking the plurality of rack units 122 in the height direction, and simultaneously connecting adjacent rack units 122 in the width direction and length direction parallel to the floor surface. In this example, two stages of rack units 122 are connected to each other in the height direction and width direction, and a plurality of rack units 122 are connected to each other in the length direction.

[0026] Each rack unit 122 defines one storage space 123 for storing a pallet 111 carrying one or more cardboard boxes 110. Each storage space 123 can be accessed by the forks of the forklift 1 from the side of the rack 120. Thus, the forklift 1 can load the pallet 111 into the storage space 123 from the side of the rack 120, and can remove the pallet 111 from the side of the rack 120 to the outside of the storage space 123. Note that the number of rack units 122 constituting the rack 120 described above in the height direction and length direction is just an example, and the rack 120 may be formed by combining other numbers of rack units 122 with each other.

[0027] The warehouse system 100 has a vertical conveying device 130 capable of conveying a pallet 111 carrying one or more cardboard boxes 110 between a lower floor 101 and an upper floor 102. The vertical conveying device 130 has a conveying mechanism 131 capable of moving up and down in a vertical conveying space, and a conveyor 132 extending to the conveying mechanism 131 on the lower floor 101 and the upper floor 102, respectively. The conveyor 132 can convey the pallet 111 conveyed to the conveyor 132 by, for example, a forklift 1 to the conveying mechanism 131, and can convey the pallet 111 conveyed by the conveying mechanism 131 to just before the forklift 1. The conveying mechanism 131 can convey the pallet 111 conveyed by the conveyor 132 from the lower floor 101 to the upper floor 102 or from the upper floor 102 to the lower floor 101.

[0028] In a plan view of the floor surfaces of the lower floor 101 and the upper floor 102, the area other than the area where the temporary storage area 112 is defined and the area where the racks 120 are arranged constitutes a movement path of the forklift 1. In reality, a predetermined area around the temporary storage area 112 and a predetermined area around the racks 120 are defined as buffer areas in which the travel of the forklift 1 is restricted. FIG. 2 is a perspective view showing a schematic structure of a forklift 1 according to an embodiment of the present invention. The forklift 1 is used to transport an article 110 placed on a pallet 111 to various positions in the warehouse system 100. As described above, the forklift 1 can travel autonomously based on its own position estimation in the warehouse system 100, but alternatively, it can travel manually by an operator.

[0029] In the following description, in the longitudinal direction of the forklift 1, the direction toward the front of the forklift 1 is defined as the forward direction FD, while the direction toward the rear of the forklift 1 opposite to the forward direction FD is defined as the rearward direction BD. Similarly, in the height direction of the forklift 1, the direction toward the top of the forklift 1 is defined as the upward direction UD, while the direction toward the bottom of the forklift 1 opposite to the upward direction UD is defined as the downward direction DD. Furthermore, in the lateral direction of the forklift 1, the direction toward the left of the forklift 1 is defined as the leftward direction LD, while the direction toward the right of the forklift 1 opposite to the leftward direction LD is defined as the rightward direction RD.

[0030] The forklift 1 has a vehicle body 10 and a handling assembly 20 disposed at the front end of the vehicle body 10. The vehicle body 10 has a main body 11, a pair of straddle legs 12, 12 extending mutually parallel in the forward direction FD from the front end of the main body 11, and a head guard 13 attached to the upper end of the main body 11. The main body 11 has, for example, at its rear end, a driver's seat 14 where an operator can stand, and on its upper surface, an operation unit 15 for the operator to operate the forklift 1. The handling assembly 20 is disposed between the straddle legs 12, 12. The head guard 13 prevents luggage and objects from falling towards the operator from above.

[0031] The vehicle body 10 includes a pair of front wheels 16 disposed at the lower parts of the respective straddle legs 12, 12 and, for example, one rear wheel (not shown) disposed at the lower part of the main body 11. A drive motor (not shown) incorporated in the main body 11, for example, is connected to the rear wheel. Electric power is supplied to the drive motor from a battery (not shown) incorporated in the main body 11 as well, for example. That is, while the rear wheel is a drive wheel, the front wheels 16 are driven wheels. The rear wheel is disposed, for example, offset to the left direction FD from the center of the forklift 1 in the left - right direction. By driving the rear wheel in the traveling direction and changing the angle in the left - right direction, the forklift 1 can move forward, backward, left, and right. Incidentally, when transporting the pallet 111, this forklift 1 travels facing the rear direction BD.

[0032] The load handling assembly 20 is an assembly capable of lifting and lowering a pallet 111. The load handling assembly 20 has a mast assembly 30 and a fork assembly 40. The mast assembly 30 is supported between a pair of straddle legs 12, 12 so as to be movable in a forward direction FD and a rearward direction RD. The fork assembly 40 is supported at the front end of the mast assembly 30 so as to be movable in an upward direction UD and a downward direction DD. In the state shown in FIG. 1, the mast assembly 30 is disposed at a position where it is maximally advanced in the forward direction FD. Also, the fork assembly 40 is disposed at a position where it is raised in the upward direction UD from the lowest position.

[0033] The mast assembly 30 has a base 31 disposed between a pair of straddle legs 12, a pair of outer masts 32 standing upright in the upward direction UD from the base 31, and a pair of inner masts 33 disposed inside the pair of outer masts 32 in the left direction LD and right direction RD, respectively. The outer masts 32 are formed integrally with the front end of the base 31, for example. The outer masts 32 are disposed spaced apart from each other at a predetermined interval in the left-right direction. The bracket 31, the outer masts 32 and the inner masts 33 are supported between the pair of straddle legs 12 so as to be movable in the forward direction FD and the rearward direction RD.

[0034] The inner masts 33, 33 stand upright in the height direction adjacent to the inner sides of the outer masts 32, 32 in the left-right direction. The inner masts 33, 33 are supported by the outer masts 32, 32 so as to be able to move in the height direction relative to the outer masts 32, 32. The fork assembly 40 is supported by the inner masts 33, 33 so as to be able to move in the height direction relative to the inner masts 33, 33. Since the fork assembly 40 is supported by the outer masts 32 via the inner masts 33, 33, it can move in the forward direction FD and rearward direction RD together with the brackets 31, the outer masts 32 and the inner masts 33.

[0035] The fork assembly 40 has a bracket 41, a pair of forks 42, 42, and a backrest 43. The bracket 41 is supported by the inner masts 33, 33 so as to be relatively movable in the height direction with respect to the inner masts 33, 33. The pair of forks 42, 42 are attached to the front surface of the bracket 41. The pair of forks 42, 42 each extend forward in the forward direction FD from the bracket 41 at a position where, for example, one outer mast 32 and one inner mast 33 are arranged in the left-right direction. The backrest 43 is attached to the upper end of the bracket 41, for example. The backrest 43 prevents the load on the pallet lifted by the fork 42 from falling backward of the fork assembly 40.

[0036] A distance measuring sensor 50 is attached to the bracket 41. In this example, the distance measuring sensor 50 is arranged at the center in the left-right direction of the forklift 1. Further, the distance measuring sensor 50 can move in the height direction together with the bracket 41, that is, the fork assembly 40. A 3D LiDAR (detection and distance measurement by light) sensor capable of detecting the presence or absence of an object within a predetermined three-dimensional detection range in the forward direction FD of the forklift 1 is used for the distance measuring sensor 50. Specifically, the distance measuring sensor 50 acquires three-dimensional point cloud data of an object within the detection range by irradiating the detection range with laser light. The point cloud data is a set of data of points having three-dimensional coordinates in the three-dimensional detection range. The point cloud data is composed of the coordinates and color information of each point, and the shape of the object within the detection range and the distance to the object are detected by measuring the distance from the distance measuring sensor 50 to each point.

[0037] FIG. 3 is a side view schematically showing the structure of the forklift 1 according to an embodiment of the present invention. In FIG. 3, a state where the fork assembly 40 is lifting the pallet 111 is shown. Referring also to FIG. 3, the three-dimensional detection range R of the distance measuring sensor 50 is defined, for example, downward of the fork assembly 40 and in the forward direction FD from the forklift 1. This detection range R is defined at a predetermined irradiation distance within a predetermined angular range in the left-right direction of the forklift 1 and a predetermined angular range in the height direction of the forklift 1. In an example of the distance measuring sensor 50, the irradiation distance is set to 3 m, the angular range in the left-right direction is set to 145 degrees, and the angular range in the height direction is set to 60 degrees. Also, the frequency of the laser light of the distance measuring sensor 50 is set to, for example, 5 to 10 Hz. These numerical values of the distance measuring sensor 50 are merely examples, and other numerical values may be set.

[0038] FIG. 4 is a plan view schematically showing the structure of the forklift 1 according to an embodiment of the present invention. As shown in FIG. 4, the forklift 1 further has three distance measuring sensors 51. The distance measuring sensor 51 is, for example, a 2D LiDAR sensor. For example, one distance measuring sensor 51 may be attached to the front end of each straddle leg 12, while one distance measuring sensor 51 may be attached to the rear end and the lower end position of the main body 11. The three distance measuring sensors 51 are arranged at the same height from the floor surface. The right front distance measuring sensor 51 has a detection range R1 in the forward direction FD and the right direction RD. The left front distance measuring sensor 51 has a detection range R2 in the forward direction FD and the left direction LD. The rear distance measuring sensor 51 has a detection range R3 in the rearward direction BD.

[0039] The detection ranges R1, R2, and R3 of these three distance measuring sensors 51 overlap each other, and as a result, the three distance measuring sensors 51 have detection ranges R1, R2, and R2 of 360 degrees around an axis defined in the height direction of the forklift 1. By irradiating these detection ranges R1, R2, and R2 with laser light, the three distance measuring sensors 51 obtain two-dimensional point cloud data of objects within the respective detection ranges R1, R2, and R2. The point cloud data is composed of the coordinates and color information of each point, and the shape of an object within the detection range and the distance to the object are detected by measuring the distance from the distance measuring sensor 50 to each point. With these distance measuring sensors 51, a two-dimensional map of the layout of the structures including the temporary storage area 112, the rack 120, the conveyor 132, etc. is generated by mapping the lower floor 101 and the upper floor 102 of the warehouse system 100.

[0040] As shown in FIG. 5, the warehouse system 100 has a management server 140 that manages the operation of the forklift 1 with respect to the warehousing, storage, and retrieval of goods, the storage status of goods in the temporary storage area 112 and the rack 120, and the like. This management is realized by the control unit (computer) executing a program stored in the storage unit, as described later. Specifically, these processes are executed according to the information processing described in the program. In other words, the information processing described in the program functions as a specific means in which software related to the program and various hardware resources of the warehouse system 100 cooperate with each other, by reading the program into the control unit. In addition, the program may be stored in a computer-readable medium that includes instructions for executing a predetermined process when executed by a computer.

[0041] The management server 140 includes a control unit 150 and a storage unit 160. The control unit 150 includes a communication control unit 151, an inventory management unit 152, and a transport control unit 153. The storage unit 160 stores a program 161 for controlling the process of receiving, storing, and shipping items from the warehouse system 100, and a map 162 showing the layout of the temporary storage area 112, the rack 120, and the conveyor 132 in the warehouse system 100. In addition to these, the storage unit 160 also stores information about items placed in the temporary storage area 112 and the rack 120 (for example, information for managing which items are placed in which locations, etc.). The control unit 150 manages the warehouse system 100 by executing the program 161 stored in the storage unit 160. The management server 140 may be realized, for example, by a physical server installed in a building in which the warehouse system 100 is established, or may be realized, for example, by a cloud server built on the Internet.

[0042] The communication control unit 151 controls communication between the management server 140 and the forklift 1. The communication method may be, for example, Wi-Fi (registered trademark), Bluetooth (registered trademark), or the like. The inventory management unit 152 manages the inventory status of the warehouse system 100. Specifically, the inventory management unit 152 manages information (SKU) for identifying each item, information on the inventory quantity of each item specified by the SKU, information (ID) for identifying the location where the item is stored, and the like, in association with each other. The transport control unit 153 manages and controls the operation of the forklift 1 and the vertical transport device 130. Specifically, the transport control unit 153 generates a transport instruction for instructing the forklift 1 as to which item from which location to transport to which location in the warehouse system 100.

[0043] To explain in more detail about the generation of the transport instruction in the transport control unit 153, the transport control unit 153 generates a transport instruction for a specified forklift 1 for each process of entering or leaving the warehouse system 100. The case of an instruction to transport goods only on the lower floor 101 or the upper floor 102 is as follows. The transport instruction in this case includes, for example, a) a first movement path from the current position of the forklift 1 to the specified pallet 111, b) an instruction regarding a pick operation to pick up the specified pallet 111, c) a second movement path to a specified location to transport the specified pallet 111, and d) an instruction regarding a drop operation to drop the specified pallet 111 at the specified location.

[0044] On the other hand, a transport instruction from the lower floor 101 to the upper floor 102, or from the upper floor 102 to the lower floor 101, is as follows. Specifically, the transport instruction includes a first transport instruction to the forklift 1 arranged on one floor, and a second transport instruction to the forklift 1 arranged on the other floor. The first transport instruction includes a) a first movement path from the current position of the forklift 1 to the specified pallet 111, b) an instruction regarding a pick operation to pick the specified pallet 111, c) a second movement path to the conveyor 132 of the vertical transport device 130, and d) an instruction regarding a drop operation to drop the specified pallet 111 onto the conveyor 132.

[0045] The second transport instruction includes a) a first movement path from the current position of the forklift 1 to the conveyor 132 of the vertical transport device 130, b) an instruction for a pick operation to pick the specified pallet 111, c) a second movement path to a specified location to transport the specified pallet 111, and d) an instruction for a drop operation to drop the specified pallet 111 at the specified location. In this way, in the case of a transport instruction from the lower floor 101 to the upper floor 102 or a transport instruction from the upper floor 102 to the lower floor 101, the transport instruction is transmitted to separate forklifts 1. Note that the first movement path and the second movement path do not need to be the shortest path, and may be a general path along which the forklift 1 can move on the map 162 of the warehouse system 100.

[0046] FIG. 5 is a functional block diagram showing a schematic configuration of the forklift 1. The forklift 1 has a control unit (computer) 60 and a storage unit 70. The control unit 60 has a communication control unit 61 and an equipment control unit 62. The storage unit 70 stores a program 71 for controlling the operation of the forklift 1 and a map 72 showing the layout of the temporary storage areas 112, the racks 120, and the conveyors 132 in the warehouse system 100. The map 72 is the same as the map 162 stored in the storage unit 160 of the management server 140. The map 72 is generated by mapping using, for example, the distance measurement (2D LiDAR) sensor 51 and the distance measurement (3D LiDAR) sensor 50. The map 72 will be described in detail later.

[0047] The control unit 60 controls the operation of the forklift 1 by executing the program 71 stored in the storage unit 70. The communication control unit 61 controls communication between the management server 140 and the forklift 1. The equipment control unit 62 controls the operation of the forklift 1. Specifically, the equipment control unit 61 can control operations related to forward movement, reverse movement, and left and right turning of the forklift 1 by driving the rear wheels, and picking and dropping of the pallet 111 by driving the mast assembly 30 and fork assembly 40 of the loading and unloading assembly 20.

[0048] FIG. 6 is a diagram that shows a schematic map 72 showing the layout of the structures of the warehouse system 100. In this example, the map 72 shows the layout of the structures 200 on the lower floor 101, for example. The structures 200 include cardboard boxes 110 (or pallets 111), racks 120, conveyors 132, and the like. The map 72 is generated by mapping using three distance measuring (2D LiDAR) sensors 51 and one distance measuring sensor (3D LiDAR) 50 of the forklift 1. Specifically, the distance measuring sensor 51 arranged at a predetermined height from the floor surface scans the shape of the structure 200 to obtain point cloud data of the two-dimensional shape of the structure 200. On the map 72, the contour shape of the structure 200 is shown based on the obtained point cloud data.

[0049] The point cloud data of the two-dimensional shape of the structure 200 on the map 72 is data that serves as a reference when the forklift 1 travels by estimating its own position. Specifically, the point cloud data of the two-dimensional shape is master data indicating the two-dimensional coordinate values ​​of the structure 200. The forklift 1 can travel while estimating its own position within the warehouse system 100 by comparing the master data shown on the map 72 with detection data indicating the two-dimensional coordinate values ​​of the structure 200 detected by the distance measuring sensor 51 while traveling. Note that the arrangement of the cardboard boxes 110 (or pallets 111) placed in the temporary storage area 112 changes over time, so the master data related to the cardboard boxes 110 (or pallets 111) may be updated periodically.

[0050] The map 72 further includes master data indicating three-dimensional coordinate values ​​of a drop position 201 at which the pallet 111 (on which the cardboard box 110 is placed) is dropped in the structure 200. In this example, the drop position 201 is defined in the accommodation space 123 of each rack unit 122 of the rack 120 or the conveyor 132 of the vertical transport device 130. The master data of the drop position 201 is generated based on point cloud data of the three-dimensional shapes of the drop positions 201 by mapping the three-dimensional shapes of the accommodation space 123 of the rack unit 122 and the conveyor 132 of the vertical transport device 130 in advance by the distance measurement sensor 50. In the map 72, the three-dimensional master data of the drop position 201 is held superimposed on the master data of the two-dimensional shape of the structure 200.

[0051] For example, the master data of the three-dimensional shape of the drop position 201 of the conveyor 132 includes the three-dimensional coordinate value of the drop position 201 on the conveyor 132, and the three-dimensional coordinate values ​​of the frame, rollers, etc. of the conveyor 132 around the drop position 201. Also, for example, the master data of the three-dimensional shape of the accommodation space 123 of each rack unit 122 of the rack 120 includes the three-dimensional coordinate value of the drop position 201 on each accommodation space 123, and the three-dimensional coordinate values ​​of the frame members 121, etc. of each rack unit 122 around the drop position 201. Also, in the above-mentioned embodiment, the rack 120 has two rack units 122 stacked in the height direction, and the three-dimensional shape value of the drop position 201 is registered as master data for each of the rack units 122 in the first and second stages.

[0052] Next, a scene in which the forklift 1 transports the pallet 111 will be described. A transport instruction is sent from the transport control unit 153 of the management server 140 to a specific forklift 1. The forklift 1 that receives the transport instruction moves from its current position to a specified pick position according to the transport instruction. During travel, the forklift 1 estimates its own position based on two-dimensional point cloud data acquired at a specific time interval by the three distance measuring sensors 51. When the forklift 1 reaches the specified pick position, the distance measuring sensor 50 recognizes the position of the insertion port on the side of the pallet 111 at the pick position. As a result, the forklift 1 inserts a pair of forks 42, 42 of the fork assembly 40 into the insertion port to lift up the pallet 111.

[0053] Thereafter, in accordance with the transport instruction, the forklift 1 travels toward the designated drop position while holding the pallet 111. The forklift 1 estimates its own position in the same manner as described above. When the forklift 1 reaches the designated drop position (for example, the rack unit 121 or the conveyor 132), the distance measurement sensor 50 acquires the three-dimensional coordinate value of the drop position. Specifically, the distance measurement sensor 50 detects point cloud data of the three-dimensional shape of the drop position. The control unit 60 compares the three-dimensional detection data with the three-dimensional master data of the drop position 201 in the map 72 stored in the storage unit 70. In this example, 3D template matching is performed using an ICP (Iterative Closest Point) method. In this manner, the drop position is recognized. The pallet 111 is dropped at the recognized drop position.

[0054] In the warehouse system 100 as described above, while the forklift 1 is moving from the current position to the pick position and while moving from the pick position to the drop position, the self-position estimation of the forklift 1 is performed based on a comparison between the two-dimensional master data defined in the map 72 and the actual two-dimensional detection data. Meanwhile, when dropping at the drop position, the drop position is specified based on a comparison between the three-dimensional master data defined in the map 72 and the actual three-dimensional detection data. Based on this specification, the forklift 1 can drop the pallet 111 at the drop position with high accuracy. In this way, by using the two-dimensional master data when the forklift 1 is moving and the three-dimensional master data when the forklift 1 is dropping, the load of data processing can be reduced.

[0055] Also, at the pick position, the pick of the pallet 111 can usually be performed by detecting the shape of the insertion port of the pallet 111 in three dimensions. In other words, since the shape of the insertion port of the pallet 111 is often fixed due to standards and the like, the pick operation can be easily performed by estimating the position of the insertion port. On the other hand, the drop position has a different shape depending on the rack unit 122, the conveyor 132, and the like. Therefore, it is advantageous to recognize the drop position in three dimensions with high accuracy. Although the above embodiment has been described using the forklift 1 as an example of a transport robot, the present invention may be applied to transport robots other than the forklift 1. Also, in the above embodiment, the drop position 201 of the structure 200 is identified by comparison with three-dimensional master data, but the structure 200 may include other structures such as, for example, a charging facility for the forklift 1 and a narrow passage in the warehouse system 100.

[0056] The same reference numbers are used throughout the drawings to refer to the same or similar components. The following embodiments are not intended to limit the invention as set forth in the claims. Features of the invention are described herein, but changes and modifications can be made without departing from the spirit and scope of the disclosed embodiments. Furthermore, particular features, structures or characteristics can be combined in any suitable manner in one or more embodiments. It is intended that the following detailed description be considered as an example only, with a true scope and spirit being indicated by the following claims.

Claims

1. A transport robot capable of transporting items in a warehouse, A sensor capable of detecting a three-dimensional shape of an object; A control unit that controls a transport operation of the transport robot, The control unit of the transport robot identifies the structure by comparing master data indicating the three-dimensional shape of the structure located locally within the warehouse with detection data indicating the three-dimensional shape of the structure detected by the sensor.

2. the structure includes a drop location for dropping the item; The transport robot according to claim 1 , wherein the control unit identifies the drop position of the structure by comparing the master data with the detection data.

3. The transport robot according to claim 1 , wherein the control unit controls the travel of the transport robot based on map data that shows a two-dimensional layout of structures in the warehouse.

4. The transport robot according to claim 1 , wherein the sensor is a three-dimensional distance measuring sensor.

5. The transport robot according to claim 1 , wherein the master data is generated by mapping using the three-dimensional distance measuring sensor.

6. The transport robot according to claim 1 , wherein the article is placed on a pallet.

7. The transport robot according to claim 6 , wherein the structure is a rack, a conveyor, or a narrow passage in the warehouse that defines a space for arranging the pallets.

8. The transport robot according to claim 1 , wherein the transport robot is a forklift.

9. The transport robot according to claim 1 , wherein the sensor detects two-dimensional coordinate values ​​of the structure during movement as part of the detection data, and estimates the self-position based on the master data and the detection data.

10. The transport robot of claim 1 , wherein the transport robot is configured to pick the pallet by detecting a shape of the slot of the pallet at a pick position based on a reference shape of the slot of the pallet.

11. The transport robot of claim 1 , wherein the transport robot is configured to drop a pallet based on a shape of the structure at a drop location.

12. The transport robot of claim 1 , wherein the transport robot is configured to pick a pallet from a floor and drop the pallet onto the structure on another floor.

13. A method for controlling a transport robot configured to transport an article in a warehouse according to any one of claims 1 to 12.

14. A system for controlling a transport robot configured to transport items in a warehouse according to any one of claims 1 to 12.

15. A computer-readable medium comprising instructions that, when executed by a computer, cause a transport robot to transport an item within a warehouse according to any one of claims 1 to 12.

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