Unmanned carrier and carriage position identification method

Abstract

This unmanned carrier comprises: a candidate recognition part that recognizes a feature part candidate of a carriage in the periphery; a reading part that reads identification information provided on the carriage or a load mounted on the carriage; and a carriage recognition part that sets a reading range on the basis of the position of the feature part candidate recognized by the candidate recognition part, and recognizes the carriage on the basis of a reading result by the reading part in the reading range.

Description

Automated guided vehicle and method for identifying vehicle position

[0001] The present specification discloses an automated guided vehicle and a method for identifying the vehicle's position.

[0002] Conventionally, automated guided vehicles that transport basket carts have been known. For example, Patent Document 1 discloses a self-propelled robot that uses a camera to capture an image of a marker on an ID display panel attached to the basket cart, acquires relative position information of the read marker with respect to the camera based on the captured image, moves to the front of the basket cart using the relative position information, and couples with the basket cart to transport the self-propelled robot.

[0003] JP 2018-90084 A

[0004] Although Patent Document 1 describes using a camera to read markers attached to a trolley to recognize the trolley, it does not mention what to do if the marker (identification information) is not attached to the trolley in a specified position, and there is still room for improvement.

[0005] A main object of the present disclosure is to more accurately recognize a cart to be transported.

[0006] The present disclosure has adopted the following means to achieve the above-mentioned main object.

[0007] The automated guided vehicle disclosed herein is an automated guided vehicle that transports a cart, and is equipped with: a candidate recognition unit that recognizes candidate characteristic features of the cart in the vicinity; a reading unit that reads identification information provided on the cart or on a cargo loaded on the cart; and a cart recognition unit that sets a reading range based on the positions of the candidate characteristic features recognized by the candidate recognition unit, and recognizes the cart based on the reading results by the reading unit within the reading range.

[0008] In the automated guided vehicle disclosed herein, by recognizing candidate feature points of the cart in the vicinity and setting the reading range of the identification information based on the positions of the candidate feature points, it becomes possible to more reliably read the identification information attached to the cart or the cargo even if the identification information is not attached to the cart in the designated position, thereby enabling more accurate recognition of the cart.

[0009] The trolley position identification method of the present disclosure is a trolley position identification method for identifying the position of a trolley, which comprises recognizing candidate feature features of the trolley in the surrounding area, setting a reading range based on the positions of the recognized candidate feature features, reading identification information provided on the trolley or luggage carried on the trolley within the reading range, recognizing the trolley based on the reading results, and identifying the position of the trolley based on the positions of the candidate feature features used to recognize the trolley.

[0010] In the method for identifying a trolley position according to the present disclosure, similar to the automated guided vehicle according to the present disclosure, even if the identification information is not attached to the trolley at a specified position, the method can more reliably read the identification information attached to the trolley or the cargo and recognize the trolley.Then, the position of the trolley can be identified from the positions of the candidate feature parts used to recognize the trolley.

[0011] 1 is a perspective view of the exterior of a plurality of basket carts arranged in a cart storage area of ​​a store or the like, and an automated guided vehicle that transports the basket carts. FIG. 1 is a perspective view of the exterior of an automated guided vehicle, a basket cart, and a marker. FIG. 2 is a perspective view of the exterior of an automated guided vehicle, a basket cart, and a marker. FIG. 3 is a perspective view of the exterior of an automated guided vehicle. FIG. 4 is a side view of an automated guided vehicle. FIG. 5 is a side view of an automated guided vehicle. FIG. 6 is an explanatory diagram showing a state in which an automated guided vehicle has slipped under a basket cart. FIG. 7 is an explanatory diagram showing a state in which an automated guided vehicle has been coupled to a basket cart. FIG. 8 is a block diagram of a transport system including an automated guided vehicle and a management device. FIG. 9 is a flowchart showing an example of a transport control routine. FIG. 10 is an explanatory diagram showing how a basket cart is recognized. FIG. 11 is an explanatory diagram showing an example of surrounding point cloud data and a set (cluster) of points. FIG. 12 is an explanatory diagram showing an example of a cart candidate. FIG. 13 is an explanatory diagram showing an example of a marker reading range.

[0012] Next, embodiments of the present disclosure will be described with reference to the drawings.

[0013] FIG. 1 is an external perspective view of a plurality of basket carts 100 arranged in a cart storage area L of a store or the like, and an automated guided vehicle 10 that transports the basket carts 100. FIGS. 2 and 3 are external perspective views of the basket carts 100 and the automated guided vehicle 10. FIG. 4 is an external perspective view of the automated guided vehicle 10. FIGS. 5 and 6 are side views of the automated guided vehicle 10. FIG. 7 is an explanatory diagram showing a state in which the automated guided vehicle 10 has slipped under the basket cart 100. FIG. 8 is an explanatory diagram showing a state in which the automated guided vehicle 10 is coupled to the basket cart 100. FIG. 9 is a block diagram of a transport system 1 including the automated guided vehicle 10 and a management device 60.

[0014] 1, a transport system 1 of this embodiment is used in a logistics center, warehouse, store, or the like having a plurality of shelves S, and includes one or a plurality of automated guided vehicles 10 and a management device 60 (see FIG. 9) that manages the operation of the automated guided vehicles 10. The automated guided vehicles 10 are autonomously traveling transport robots (AMR: Autonomous Mobile Robot) that are coupled to carts 100 and transport the vehicles to designated shelves S.

[0015] As shown in FIG. 2 , the basket cart 100 has a rectangular, mesh-shaped platform 101 capable of carrying cargo C, and a plurality of (four) casters 110 rotatably attached to the four corners of the underside of the platform 101. A marker M, such as an AR marker, a two-dimensional code, or a barcode, for identifying the basket cart 100 is provided on the platform 101 of the basket cart 100 (in the present embodiment, the center of the outer edge front end surface of the platform 101). By reading the marker M, the automated guided vehicle 10 recognizes the basket cart 100 to be transported (transport target vehicle) and the type of cargo C loaded on the platform 101. Note that the marker M may be attached to the cargo C loaded on the platform 101, as shown in FIG. 3 . Furthermore, the identification information for identifying the basket cart 100 and the cargo C is not limited to the marker M. For example, the identification information may be a unique ID for identifying the basket cart 100. The identification information may also be identification information (such as letters or a picture) written on the outer box of the package C.

[0016] As shown in FIG. 4 , the automated guided vehicle 10 of this embodiment has a low, flat, rectangular parallelepiped appearance. The automated guided vehicle 10 includes a vehicle body 11, a plurality of (e.g., four) wheels 21 rotatably attached to the bottom surface of the vehicle body 11, and a plurality of (e.g., four) drive motors 22 (see FIG. 9 ) that rotate and drive the corresponding wheels 21. In this embodiment, the wheels 21 are configured as Mecanum wheels, each having a plurality of rollers rotatable around an axis inclined at 45 degrees relative to the rotation axis of the wheel. The automated guided vehicle 10 can move the vehicle body 11 in all directions and turn (such as by making a pivot turn, a pivot turn, or a gentle turn) by independently controlling the rotation direction and rotation speed of the corresponding wheels 21 using the plurality of drive motors 22. The wheels 21 may also be configured as omniwheels having a plurality of rollers rotatable around an axis that intersects the rotation axis of the wheel. That is, the plurality of wheels 21 may be any type of wheels as long as they can move the vehicle body 11 in a plurality of directions and turn.

[0017] 5 and 6 , the automated guided vehicle 10 also includes a connecting unit 30 that is provided on the upper surface of the vehicle body 11 and can be connected to the cart 100 when the vehicle body 11 is positioned below the cart 100. The connecting unit 30 includes a flat lift plate 31, connecting pins 32, 33, and 34 that extend upward relative to the lift plate 31, and a lifting device 35 that raises and lowers the lift plate 31. The lift plate 31 covers the upper surface of the vehicle body 11 and has a width that is substantially the same as the width of the vehicle body 11 and a front-to-rear width that is slightly shorter than the front-to-rear width of the vehicle body 11. The connecting pin 32 is provided at the front of the lift plate 31, the connecting pin 33 is provided at the rear of the lift plate 31, and the connecting pin 34 is provided in an intermediate portion between the front and rear of the lift plate 31. 7 and 8 , when the vehicle body 11 is submerged under the cart 100 and the lifting plate 31 is raised by the lifting device 35, at least one of the connecting pins 32, 33, 34 engages with the back side of the loading platform 101 of the cart 100. This connects the automated guided vehicle 10 and the cart 100, and the automated guided vehicle 10 can transport (tow) the cart 100.

[0018] As shown in FIGS. 4 to 6 , contact detection sensors 36 (spring sensors) are provided on both the left and right sides of the lift plate 31 to detect when the connecting portion 30 (connecting pins 32, 33, 34) comes into contact with (connects to) the loading platform 101 of the cart truck 100. The contact detection sensors 36 have a plate that is biased upward by a spring, with its upper end at approximately the same height as the connecting pins 32, 33, 34 relative to the lift plate 31. When the connecting pins 32, 33, 34 engage with the loading platform 101 of the cart truck 100, the plate of the contact detection sensor 36 comes into contact with the loading platform 101, and the spring is compressed as it descends relative to the connecting pins 32, 33, 34. The contact detection sensor 36 detects when the connecting portion 30 comes into contact with (connects to) the loading platform 101 of the cart truck 100 by detecting that the plate has descended relatively.

[0019] As shown in FIG. 9 , the automated guided vehicle 10 further includes a control unit 40 that controls the entire system, a memory unit 41 that stores various information including map information 41a, a communication unit 42 that communicates (wirelessly communicates) with a management device 60, a camera unit 51 as an imaging device, sensors 52 and 53, and a light-emitting unit 54 that illuminates the area ahead of the vehicle body 11. The camera unit 51 is installed on the front of the vehicle body 11 to recognize the area ahead of the vehicle body 11. The sensors 52 and 53 are installed on the front and rear of the vehicle body 11, respectively, to detect surrounding objects. The sensors 52 and 53 detect surrounding objects and the distances to the objects. In this embodiment, the sensors 52 and 53 are LiDAR (Light Detection and Ranging) sensors that scan the surroundings with laser light, receive each reflected light, and measure the time it takes for the reflected light to be received, thereby measuring distance data for each scan angle and obtaining two-dimensional point cloud data of the surroundings. The light emitting unit 54 is installed on the front of the vehicle body 11 and illuminates the area ahead, making it easier for the camera unit 51 to recognize surrounding objects in dark places.

[0020] The control unit 40 is configured as a microprocessor centered on a CPU, and in addition to the CPU, includes a ROM for storing processing programs, a RAM for temporarily storing data, a timer, etc. As shown in Fig. 9, the control unit 40 receives inputs such as image signals from the camera unit 51, detection signals from the sensors 52 and 53, and detection signals from the contact detection sensor 36. The control unit 40 outputs control signals to the drive motor 22 and the lifting device 35.

[0021] 9, the management device 60 includes a processing unit 61, a storage unit 62, and a communication unit 63 for communicating (wirelessly communicating) with each automated guided vehicle 10. Although not shown, the management device 60 is also connected to input devices such as a mouse and a keyboard, a display, a printer, and the like. The processing unit 61 is configured as a microprocessor centered around a CPU, and in addition to the CPU, includes a ROM for storing processing programs, a RAM for temporarily storing data, and the like. The storage unit 62 is a storage device such as an HDD or SSD, and stores various types of information such as map information 62a and destination information 62b.

[0022] The destination information 62b is information that associates the type of luggage with the destination of the luggage, and is registered in advance by the operator. Furthermore, the management device 60 creates a unique marker M for each type of luggage at the operator's instruction and prints (issues) the created marker M using a printer. The operator then attaches the printed marker M to a specified location on the cart 100 or to the luggage loaded on the cart 100. In this way, the automated guided vehicle 10 can recognize the type of luggage to be transported by reading the marker M with the camera unit 51, and can obtain the destination (destination) of the cart 100 (transport target vehicle) loaded with the luggage based on the recognized type of luggage.

[0023] Next, the operation of the transport system 1 of this embodiment configured as described above will be described. In particular, as shown in FIG. 1, the operation of the automated guided vehicle 10 when transporting a plurality of basket carts 100 arranged in a cart storage area L one by one to their respective destinations will be described. FIG. 10 is a flowchart showing an example of a transport control routine executed by the control unit 40 of the automated guided vehicle 10. This process is executed when an instruction to transport a basket cart 100 (baggage) is received from the management device 60. Below, as shown in FIG. 11, the operation of the automated guided vehicle 10 recognizing and locating a nearby basket cart 100 when transporting the basket cart 100 will be described.

[0024] When the transport control routine is executed, the control unit 40 first controls the drive motor 22 to move the cart to a predetermined position in the cart storage area L (S100). Next, the control unit 40 measures point cloud data around the cart storage area L using the sensor unit 52 (LiDAR) (S102). Next, the control unit 40 extracts a set of points (hereinafter referred to as a cluster) that are included within a predetermined measurement distance range α from the automated guided vehicle 10 from the measured point cloud data (S103). FIG. 12 is an explanatory diagram showing an example of point cloud data and clusters around the automated guided vehicle 10. Here, the predetermined measurement distance range α is a range that includes the distance measured from the automated guided vehicle 10 to the caster 110 of the cart 100 placed in the cart storage area L, and is determined by taking into account a predetermined margin in addition to a distance experimentally measured in advance. Therefore, one cluster becomes a caster candidate that may be one caster 110. Then, the control unit 40 determines whether or not a plurality of clusters (caster candidates) have been extracted (S106). If the control unit 40 determines that a plurality of clusters have not been extracted, it determines that the cart 100 has not been found, and ends the transport control routine.

[0025] On the other hand, when the control unit 40 determines that multiple clusters have been extracted, it extracts, from the extracted multiple clusters, a combination of clusters that falls within a predetermined caster distance range β as a cart candidate (S108). FIG. 13 is an explanatory diagram showing an example of a cart candidate. The predetermined caster distance range β is a range that includes the distance between the two front wheels (casters 110) of the cart cart 100, and is determined by taking into account a predetermined margin for the specified caster distance. Therefore, a combination of two clusters that falls within the predetermined caster distance range β is a cart candidate that may be a single cart cart 100. However, if the cart candidate is recognized as a single cart cart 100 as it is, there is a possibility that the cart cart 100 will be erroneously recognized. For example, as shown in Figure 11 , when two basket carts 100 are placed close to each other, the caster 110 of one basket cart 100 and the caster 110 of the other basket cart 100 may fall within the specified inter-caster distance range β, which could result in parts of the two basket carts 100 being erroneously recognized as a single basket cart 100. Also, as shown in Figure 11 , when there are other members P that can be recognized as a cluster around the basket cart 100, the caster 110 of the basket cart 100 and the other members P may fall within the specified inter-caster distance range β, which could result in these being erroneously recognized as a single basket cart 100. Therefore, in this embodiment, the control unit 40 performs the following process to accurately recognize the basket cart 100 from among the candidate carts.

[0026] That is, after extracting the trolley candidates, the control unit 40 sets a marker reading range for each trolley candidate (S110). FIG. 14 is an explanatory diagram showing an example of the marker reading range. The marker reading range is determined to include the designated attachment position of the marker M based on the position of the combination of two clusters (caster candidates). In this embodiment, the marker reading range includes a margin so that the marker M can be read correctly even if the attachment position of the marker M is slightly deviated from the designated position. For example, as shown in FIG. 2, if the center of the outer edge front end face of the loading platform 101 is designated as the attachment position of the marker M, the marker reading range is determined to include the entire area of ​​the outer edge front end face so that the marker M can be read correctly regardless of where the marker M is attached on the outer edge front end face of the loading platform 101.

[0027] Then, the control unit 40 reads the marker M within the marker reading range for each candidate trolley using the camera unit 51 (S112), and determines whether or not there is a candidate trolley whose marker M has been successfully read (S114). If the control unit 40 determines that there is no candidate trolley whose marker M has been successfully read, it determines that the basket trolley 100 has not been found, and ends the transport control routine.

[0028] On the other hand, if the control unit 40 determines that there is a vehicle candidate whose marker M has been successfully read, it sets the corresponding vehicle candidate as the vehicle to be transported (S116). If the control unit 40 determines that there are multiple vehicle candidates whose marker M has been successfully read, it sets the vehicle candidate that is closest to the automated guided vehicle 10 as the vehicle to be transported. Next, the control unit 40 identifies the position of the vehicle to be transported based on the position of the combination of the two clusters (casters 110) used to recognize the vehicle to be transported (S118). For example, the position of the vehicle to be transported can be the center position between the two clusters.

[0029] Next, the control unit 40 couples the basket cart 100 (cart to be transported) (S120). This process is performed as follows. That is, the control unit 40 first controls the drive motor 22 so that it slides under the cart to be transported from between the two casters 110 of the cart to be transported, and then uses the lifting device 35 to raise the coupling pins 32, 33, and 34 so that they engage with the platform 101 of the cart to be transported, thereby coupling the cart to the cart to be transported. The control unit 40 then sets a destination and starts transporting the cart to be transported (S122). The destination is set by recognizing the type of cargo C to be loaded on the cart to be transported from the marker M read in S112, acquiring a destination for the cargo C corresponding to the recognized type of cargo C, and setting the destination. The destination is acquired by receiving the destination derived from the destination information 62b based on the recognized type of cargo C from the management device 60. Furthermore, the transport of the transport target cart is performed by acquiring a transport route and controlling the drive motor 22 to start transport from the cart storage area L to the destination according to the acquired transport route. The transport route is acquired by determining the surrounding shape based on point cloud data measured by the sensor units 52, 53 (LiDAR), recognizing the current location of the vehicle by comparing (collating) the determined surrounding shape with map information 41a stored in the memory unit 41, and performing a route search based on the recognized current location and the specified destination using the map information 41a. Note that the transport route may also be acquired by recognizing the current location and transmitting it to the management device 60, and receiving a transport route generated by the management device 60 based on the current location.

[0030] When the control unit 40 starts transporting the target cart, it acquires its own position (S124) and determines whether it has arrived at the destination (S126). If the control unit 40 determines that it has not arrived at the destination, it returns to S124. If the control unit 40 determines that it has arrived at the destination, it stops traveling (S128), releases the connection with the target cart (S130), and returns to S100. Specifically, the control unit 40 releases the connection with the target cart by lowering the connecting pins 32, 33, and 34 using the lifting device 35. In this way, the automated guided vehicle 10 couples to one of the multiple carts 100 arranged in the cart park L and transports it to its destination. After completing the transport to the destination, the automated guided vehicle 10 returns to the cart park L and transports the next cart 100. This operation is repeated, thereby transporting the multiple carts 100 arranged in the cart park L. The control unit 40 stores in the memory unit 41 the coupling position when coupled to the transport target cart in S120, and when returning to the cart storage area L in S100, controls the drive motor 22 so that the cart moves to the coupling position stored in the cart storage area L. This makes it possible to sequentially recognize and transport a plurality of basket carts 100 lined up in the cart storage area L.

[0031] Here, the correspondence between the main elements of the embodiment and the main elements of the present disclosure described in the claims will be explained. That is, the cart 100 of the present embodiment is an example of a cart of the present disclosure, the control unit 40 and the sensor units 52 and 53 that execute the processes of S102 and S104 of the transport control routine are examples of a candidate recognition unit, the camera unit 51 is an example of a reading unit, and the control unit 40 and the camera unit 51 that execute the processes of S106 to S118 of the transport control routine are examples of a cart recognition unit. Also, the sensor units 52 and 53 are examples of a measurement unit.

[0032] It goes without saying that the present disclosure is not limited to the above-described embodiments, and can be embodied in various forms as long as they fall within the technical scope of the present disclosure.

[0033] For example, in the above-described embodiment, the control unit 40 terminates the transport control routine if the basket cart 100 cannot be found in the cart parking area L, but if the basket cart 100 is placed in multiple different cart parking areas, if the basket cart 100 cannot be found in one cart parking area, it may move to another cart parking area and search for the basket cart 100.

[0034] In the embodiment described above, the automated guided vehicle 10 engages the connecting pin 34 of the connecting portion 30 with the loading platform portion 101 of the basket cart 100 to tow the basket cart 100. However, the automated guided vehicle 10 may also be configured to lift the basket cart 100 with the connecting portion 30 and transport it.

[0035] As described above, the automated guided vehicle disclosed herein recognizes candidate feature points of the cart in the vicinity and sets the reading range for the identification information based on the positions of the candidate feature points, thereby making it possible to more reliably read the identification information attached to the cart or cargo even if the identification information is not attached to the cart in the designated position. As a result, the cart can be recognized more accurately.

[0036] The automated guided vehicle according to the present disclosure may further include a measurement unit that measures point cloud information about the surrounding area, and the candidate recognition unit may recognize the feature candidates based on the point cloud information measured by the measurement unit. This makes it possible to easily recognize feature candidates suitable for recognizing the vehicle.

[0037] In this case, the trolley recognition unit may set the read range based on the positions of the feature candidate recognized by the candidate recognition unit, and if the identification information included in the read range is successfully read, recognize the trolley as a trolley and identify the position of the trolley based on the positions of the feature candidate used to recognize the trolley. Alternatively, the candidate recognition unit may recognize caster candidate for the trolley from the point cloud information measured by the measurement unit, extract combinations of caster candidate from the caster candidate recognized by the candidate recognition unit that are separated from each other by a predetermined range of caster distances, set the read range based on the positions of the extracted combination of caster candidate, and if the identification information included in the read range is successfully read, recognize the trolley as a trolley and identify the position of the trolley based on the positions of the caster candidate combination used to recognize the trolley. In this way, in addition to recognizing the trolley, it is possible to more accurately identify the position of the trolley from the positions of the feature candidate. In the latter case, the candidate recognition unit may recognize a set of points within a predetermined measurement distance from the point cloud information as the anchor candidate. In this way, anchor candidates can be appropriately recognized by measuring the point cloud information.

[0038] The present disclosure is not limited to the form of an automated guided vehicle, but may also be in the form of a method for identifying the position of a carriage.

[0039] The present disclosure is applicable to the automated guided vehicle manufacturing industry and the like.

[0040] 1 Automated guided vehicle system, 10 Automated guided vehicle, 11 Vehicle body, 21 Wheels, 22 Drive motor, 30 Connection portion, 31 Lifting plate, 32, 33, 34 Connection pin, 35 Lifting device, 36 Contact detection sensor, 40 Control portion, 41 Memory portion, 41a Map information, 42 Communication portion, 51 Camera portion, 52, 53 Sensor portion, 54 Light emitting portion, 60 Management device, 61 Processing portion, 62 Memory portion, 62a Map information, 62b Destination information, 63 Communication portion, 100 Basket cart, 101 Loading platform portion, 110 Caster, L Cart storage area, M Marker, S Shelf.

Claims

1. An unmanned guided vehicle that transports a cart, comprising: a candidate recognition unit that recognizes candidate characteristic parts of the cart in the surrounding area; a reading unit for reading identification information provided on the cart or on luggage loaded on the cart; and a cart recognition unit that sets a reading range based on the positions of the candidate characteristic parts recognized by the candidate recognition unit, and recognizes the cart based on the reading results by the reading unit within the reading range.

2. An automated guided vehicle according to claim 1, comprising a measurement unit that measures surrounding point cloud information, and the candidate recognition unit recognizes the feature candidates based on the point cloud information measured by the measurement unit.

3. An unmanned guided vehicle as described in claim 2, wherein the cart recognition unit sets the reading range based on the positions of the candidate feature parts recognized by the candidate recognition unit, and when reading of the identification information included within the reading range is successful, recognizes that it is a cart and locates the position of the cart based on the positions of the candidate feature parts used to recognize the cart.

4. An unmanned guided vehicle as described in claim 2, wherein the candidate recognition unit recognizes caster candidates for the trolley from the point cloud information measured by the measurement unit, and the trolley recognition unit extracts combinations of caster candidates separated from each other by a predetermined range of caster distances from the caster candidates recognized by the candidate recognition unit, sets the reading range based on the position of the extracted combination of caster candidates, and, when successful in reading the identification information included within the reading range, recognizes it as a trolley and specifies the position of the trolley based on the position of the combination of caster candidates used to recognize the trolley.

5. An automated guided vehicle according to claim 4, wherein the candidate recognition unit recognizes a set of points within a predetermined measurement distance range from among the point cloud information as the caster candidates.

6. A trolley position identification method for identifying the position of a trolley, comprising: recognizing candidate characteristic parts of the trolley in the surrounding area; setting a reading range based on the positions of the recognized candidate characteristic parts; reading identification information provided on the trolley or luggage carried on the trolley within the reading range; recognizing the trolley based on the reading results; and identifying the position of the trolley based on the positions of the candidate characteristic parts used to recognize the trolley.

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