Method and system for conveying articles

Abstract

The invention relates to a method for transporting articles (P1, P2, P3, P4, P5) in an internal logistics system (1) using autonomous mobile robots (A, B, C), each autonomous mobile robot being able to transport an article (P1, P2, P3, P4, P5) in a transport line (2) of the system, the method comprising a step of forming a queue (C1, C2), the queue comprises at least two mobile robots (A, B, C) traveling at the same speed at least along a section of the route (2). The invention also relates to a system for carrying out the method and to a facility for sorting articles comprising such a system.

Description

Technical Field

[0001] The present invention relates to the field of internal logistics and to a system and method for conveying objects using autonomous mobile robots (or automated guided vehicles), each autonomous mobile robot being able to move at least one item.

[0002] Such a conveying system can be used, for example, in sorting facilities or in automatic storage systems. Prior art

[0003] Many applications, such as the ones described above, use autonomous mobile robots (AMRs) or automated guided vehicles (AGVs) to transport objects to be sorted or stored in internal logistics facilities. A large number of such robots / vehicles operating simultaneously in a line creates a risk of collision between robots / vehicles and means that their movements need to be managed with this factor in mind. In general, the risk of collision is limited by using lines without intersections or by implementing priority rules to manage the order in which AMRs / AGVs pass through intersections. These rules may be satisfactory in some cases when the work rate is low, but they are usually insufficient when the task to be performed requires a high work rate (whether sorting, storing or preparing items for outbound delivery).

[0004] Furthermore, known systems only address certain situations by slowing down the pace. For example, when two robots / vehicles are traveling in tandem in the same lane, a slight deviation of the leading robot from the path will cause the trailing robot to slow down or stop to avoid a collision. Such repeated occurrences of slowing down and / or stopping inevitably reduce the working rate of the robots / vehicles and, therefore, the working rate of the entire system.

[0005] The purpose of the present invention is to propose a new solution for increasing the working rate of AMR / AGV on internal logistics lines while limiting the risk of collisions. Summary of the invention

[0006] To this end, the present invention relates to a method for conveying objects in an internal logistics system using autonomous mobile robots or automated guided vehicles, each autonomous mobile robot or automated guided vehicle being capable of conveying one object in a conveying line of the system, the method comprising the step of forming a queue comprising at least two robots / vehicles travelling at the same speed along at least one section of the conveying line.

[0007] By forming a platoon, the average distance between autonomous mobile robots or automated guided vehicles can be reduced, thereby increasing throughput.

[0008] A platoon is a group of autonomous mobile robots (or AGVs) moving along a single track or along parallel tracks close to each other (according to a defined separation distance) and at substantially the same speed.

[0009] "Substantially the same speed" means that AMRs / AGVs in the same queue may, for example, have the same speed on straight sections of the line and may have the same speed profile on bends to change direction, their speeds remaining very close along the route.

[0010] Advantageously, the queue formation step is performed in a so-called lead-in section and comprises a grid defining theoretical positions, each theoretical position being capable of being occupied by an autonomous mobile robot, the grid comprising a plurality of parallel tracks and a plurality of successive parallel rows intersecting the tracks and forming a non-zero angle with these tracks, the queue comprising two or more robots of different rows positioned so that two robots of successive rows of the same track are spaced apart by a predetermined minimum distance.

[0011] Using this theoretical position grid, different possible AMR (or AGV) arrangements can be generated to form a queue. Such positions can include queues with single-track robots or robots from different tracks. The queue is formed in the lead-in section of the line. The robots arriving in this section can have different speeds, and these robots are organized in this area by adjusting their speeds and / or changing their positions so that they are placed on one or more tracks, and where each row corresponds to the rows of the theoretical grid. Once a queue has been formed, the mobile robots (or AGVs) move together at substantially the same speed. Optionally, the best configuration can be selected by comparing possible configurations. This configuration can be selected so that the AMR can move more smoothly.

[0012] The minimum distance avoids collisions between mobile robots on the same track along the route.

[0013] Advantageously, the queue forming step comprises a sub-step in which two theoretical grid positions of the same row and belonging to two adjacent tracks are offset in the longitudinal direction of the lead-in section by a distance equal to the distance between said two adjacent tracks (in the transverse direction).

[0014] Advantageously, each row in the introduction section forms an angle of +45° or -45° with the track, corresponding to a positive or negative orientation of the queue, respectively.

[0015] Advantageously, a distribution section connected to the introduction section is added to the conveying line, the distribution section having one or more parallel robot entrance tracks intersecting with several parallel robot exit tracks, the exit tracks forming a non-zero deflection angle with the robot entrance tracks; the method also includes the step of moving the robots of the queue between the entrance tracks and the exit tracks at substantially the same speed.

[0016] Advantageously, the deflection angle defines a positive or negative orientation of the dispensing section. If the angle is negative (positive), the dispensing section is considered to be negatively (positively) oriented.

[0017] The number of entry tracks may be equal to the number of tracks in the lead-in area.

[0018] Since the distribution section is formed by one or more entrance tracks that intersect the exit tracks, at each intersection, the AMR / AGV can change direction so that all exits can be entered from any entrance. This allows the best route to be selected and thus increases throughput by increasing the possible routes.

[0019] In addition, when the allocation section is traversed by a queue with the correct configuration (orientation and distance between vehicles), no collisions between vehicles occur, regardless of which exit is chosen. In particular, this is made possible by maintaining a minimum distance between robots on the same track and by longitudinally offsetting the range belonging to parallel tracks.

[0020] Advantageously, the robots may be controlled to be grouped together in a configuration that forms a queue at the exit of the dispensing section.

[0021] Advantageously, an additional distribution section is added to the line, the additional distribution section having one or more parallel second robot entrance tracks intersecting one or more parallel second robot exit tracks, the second exit tracks forming a non-zero deflection angle with the second robot entrance tracks and optionally having an orientation opposite to the angle of the distribution section; the method also includes the step of moving the queue between the second entrance track and at least one of the second exit tracks at substantially the same speed. This increases the number of possible routes and avoids collisions, making the movement of the AMR / AGV smoother.

[0022] Advantageously, the deflection angle defines a positive or negative orientation of the distribution section. If the angle is negative (positive), the distribution section is considered to be negative (positive).

[0023] This increases the number of possibilities for the AMR / AGV to change direction without risk of collision.

[0024] Advantageously, the allocation section and / or the additional allocation section may be unidirectional in order to reduce the risk of collision.

[0025] According to an example of embodiment, the deflection angle of the distribution section and / or the additional distribution section is -90° or 90°.

[0026] When two allocation sections are arranged successively, the orientation of the second allocation section may depend on the orientation of the first allocation section. For example, if the allocation section is positively oriented (the deflection angle is positive), the second allocation section will be negatively oriented.

[0027] The orientation of the queue in the incoming section may depend on the orientation of the allocated section. For example, if the allocated section is positively oriented, the queue will also be positively oriented.

[0028] Advantageously, the method may comprise a step for changing the orientation of the queue by accelerating and / or decelerating the autonomous mobile robot in a reorientation zone provided between two consecutive allocation sections.

[0029] According to one embodiment, the distance between the two tracks a=L+d, where L is the length of the robot. In this advantageous embodiment, when the parallel connecting tracks between two consecutive allocation sections are spaced apart by L+d (L is the length of the vehicle, and d is the distance between two vehicles in the queue), there is no need to change the orientation of the queue to avoid collisions.

[0030] In some example embodiments, the formation includes at least two autonomous mobile robots on the same track.

[0031] According to an example embodiment, when a first robot followed by a second robot in the same queue on the same entrance track takes a first exit track, the second robot takes a second exit track that is located before the first exit track.

[0032] This avoids collisions between robots / vehicles on the same track and in the same queue.

[0033] For example, when a first robot in a first row and a second robot in a next row of the same queue arrive via two parallel entrance tracks and intend to use the same exit track, the first robot arrives via the first entrance track and the second robot then arrives via the second entrance track further away from the exit end of the exit track.

[0034] This prevents collisions between consecutive parallel robots / vehicles in the same queue.

[0035] Advantageously, one queue is spaced apart from the preceding queue by a predetermined safety distance D. This avoids collisions between the mobile robots of two consecutive queues in an allocation section.

[0036] The invention also relates to a computer program comprising instructions for executing the steps of the above method.

[0037] The invention also relates to a computer comprising the above-mentioned computer program Readable medium.

[0038] The present invention also relates to an internal logistics conveying system, which comprises:

[0039] - Multiple autonomous mobile robots, each capable of transporting an object,

[0040] - ground conveyor lines, in which mobile robots can operate,

[0041] - A computer program as described above.

[0042] The system is configured to perform the method as described above.

[0043] The present invention also relates to an article sorting facility, which comprises a sorting area and a conveying system as described above.

[0044] The invention also relates to an automatic object storage facility comprising an object storage area having a plurality of storage levels and raising and lowering means connecting said levels; said facility also comprising a conveying system as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Other characteristics and advantages of the invention will become apparent from the following description with reference to the accompanying drawings given as non-limiting examples, in which:

[0046] Figure 1 A conveyor line is schematically shown, wherein the robots form a queue;

[0047] Figure 2 The lead-in section is schematically shown;

[0048] Figure 3 An example of an allocation section connected to an incoming section is shown;

[0049] Figure 4 Two successive allocation sections are shown;

[0050] Figure 5 The reorientation area is shown;

[0051] Figure 6 An example of a sorting plant carrying out the method according to the invention is shown.

[0052] In the rest of the specification, elements having the same structure or similar functions will be denoted by the same reference numerals. DETAILED DESCRIPTION

[0053] Figure 1 is a partial schematic diagram of an intralogistics conveying system 1. The system 1 comprises a conveying line 2 (partially shown) and a group of autonomous mobile robots (AMRs) or AGVs (labeled A1, B1, C1, A2, B2). For simplicity, only AMRs will be mentioned in the following description, keeping in mind that they can also be AGVs or other similar conveying devices, sometimes called shuttles or carts in the field of intralogistics.

[0054] The system also includes control means, not shown. Such means may include a central control means communicating with local control means arranged in each AMR. The control means includes one or more computer control programs.

[0055] Line 2 includes, for example, Figure 1 2 parallel tracks as shown. Robots A1, B1 and C1 running successively on the same track form a first queue C1, in which robots A1, B1, C1 run at the same speed and each robot is separated from the next robot by a safety distance d. The distance d is determined to avoid collision between each robot in the same queue running on the same track and the next robot.

[0056] AMRs A' and B' travel on two parallel tracks at the same speed, forming a second queue C2. C1 and C2 are separated by a safety distance D, which is determined to avoid collision between the AMRs of C1 and C2 in the allocation section to be described later.

[0057] The minimum number of AMRs required to form a queue is 2 and is determined by applying the queue principles.

[0058] exist Figure 1 In the figure, these AMRs convey items P1, P2, P3, P4, P5; however, this is not necessary, because the AMRs can form a queue without being loaded, for example after storing the items in a warehouse.

[0059] Figure 2 An example of an introduction section according to the invention is schematically shown. Such a section is a part of a transport line 20 in which at least one train is formed. A transport line may have one or more introduction sections.

[0060] like Figure 2 As shown, the lead-in section may include one or more tracks T1, T2, T3. In this example, there are 3 tracks, but the number may be different.

[0061] To generate a queue in the incoming section, define a grid of theoretical positions, such as Figure 2The grid includes tracks T1, T2, T3 of line 20 and several parallel rows R1, R2, R3 that intersect tracks T1, T2, T3. Each intersection shows a theoretical position that an AMR / AGV can theoretically occupy. The minimum number of rows in a queue is 2.

[0062] To define a queue, each row R1, R2, R3 is occupied only once, regardless of the track. Thus, a queue can be formed where the robots are on the same track, e.g. Figure 1 C1 in; it is also possible to form a multi-track queue, such as Figure 2 The queue and Figure 1 C2 in.

[0063] Advantageously, every two theoretical positions on the same track are spaced apart by a predetermined safety distance d.

[0064] Therefore, two consecutive robots in the same queue running on the same track can also be separated by the same distance.

[0065] Furthermore, two theoretical positions of the same row (eg R1 ) located on two adjacent tracks (eg T1 , T2 ) may advantageously be offset by a distance a which is equal to the distance between T1 and T2 .

[0066] Furthermore, the offset of the positions and the intersection of the rows with the track form a positive or negative angle, such as +45° or -45°. Figure 2 Therefore, the queue formed by AMRs A3, B3, and C3 is negatively oriented.

[0067] Figure 3 Shows that with Figure 2 An example of a conveying system 10 with an entrance section Si having the same entrance section as shown. The system 10 also includes a distribution section Sd1. In this example, section Sd1 is formed by three AMR entrance tracks E11, E12, E13 in the extension of the tracks T1, T2, T3 of the introduction section. The section also includes exit tracks S11, S12, S13 that intersect with the entrance tracks. In this example, the deflection angle formed is +90°. In other examples, the angle may be different. The robot arriving at the entrance E11, E12, E13 can go straight forward into the intersection or turn to take the nearby exit S11, S12, S13. In this way, each AMR or AGV can take any one of the exits S11, S12, S13. Due to the minimum distance d and longitudinal offset between positions on the same range belonging to two parallel tracks, the risk of collision is avoided when the AMR / AGV in the queue travels at substantially the same speed.

[0068] Optionally, to further ensure collision-free travel, when a first robot followed by a second robot in the same queue on the same entry track adopts a first exit track, the second robot is required to adopt a second exit track preceding the first exit track.

[0069] For example, when two consecutive AMRs of a queue arrive at track E11, the first AMR takes exit S13, and the second AMR is required to take one of exits S12 or S11.

[0070] Advantageously, when a first row of robots and a next row of robots in the same queue arrive via two parallel entrance tracks and intend to use the same exit track, a robot arrives via the first entrance track and the second robot then arrives via the second entrance track further away from the exit end of the exit track.

[0071] For example, AMRs A3 and C3 can use the same exit without colliding.

[0072] Advantageously, the inlet track and the outlet track can have the same length. In addition, at the intersection, the optional radius of curvature is the same along the track in the flow direction. Advantageously, the distribution section can be unidirectional. This further ensures collision-free travel.

[0073] Figure 4 Another embodiment is shown, in which in addition to the above-mentioned distribution section Sd1, the transmission line 11 also includes a second consecutive distribution section Sd2, which can be the same as or different from Sd1, but is adapted in orientation to the arrangement of the outlet of Sd1. In addition, the same rules described above for Sd1 can be applied to Sd2.

[0074] Figure 5 Another example of a conveying system 12 is shown that includes a reorientation zone Zi located between two distribution sections.

[0075] In this example, AMRs A4, B4, C4 form a queue of negative orientation, which is incompatible with the next assigned section, which is also of negative orientation. To adjust the orientation of the queue, a direction change step is performed in the zone Zi by accelerating and / or decelerating the robots located on the autonomous tracks T1 and T3, so that C4 moves to the first row R1 and A4 moves to the third row R3.

[0076] In this configuration, the robot can travel in the allocation section without risk of collision following the rules described for Sd1.

[0077] Figure 6An example of a sorting facility 100 for carrying out the method according to the invention is shown. The facility 100 comprises a sorting area 101 in which chutes 102 are arranged in several lines. At the exit of the sorting area there is an area 103 to which the AMR / AGVs arrive after being unloaded into the chutes 102. The area 103 is a distribution section that minimizes the number of vehicles required for sorting. Optionally, a reversing section 108 may be provided between the area 101 and the area 103 to correctly reorient the AMR / AGVs leaving the sorting area 101.

[0078] At the beginning of the sorting method, a queue is formed in the incoming section 104, after which the queue passes through a loading area 105 known to those skilled in the art to receive the parcels to be sorted. The AMR then passes through a first distribution section 106 and a second distribution section 107, which leads to the sorting line of the sorting area 101. Finally, each item is unloaded into the target chute 102. In this example, the spacing between the tracks in area 107 and area 103 is equal to L+d, so that the distribution sections 106 and 107 can have the same orientation without the risk of collision of the AMR / AGV.

[0079] This example of application is of course not limiting, as many other applications are possible; for example, the sorting system can be modified by adding additional sorting lines and distribution sections.

[0080] In one variation, area 103 can be simplified to a gathering and waiting area where AMRs / AGVs gather after unloading into chute 102. In this case, reversing section 108 is no longer required. In area 103, the track pitch also does not have to be equal to L+d.

[0081] Another application example is the use of a similar conveying system in an automated storage facility, which has an introduction section and a distribution section. In addition, such facilities are known to include multi-level storage areas and one or more raising / lowering devices.

[0082] In this case, for example, a gathering area can be left in front of each raising / lowering device in case the device is not yet available when the AMR / AGV arrives.

Claims

1. A method for conveying objects (P1, P2, P3, P4, P5) in an internal logistics system (1; 10; 11; 12) using autonomous mobile robots (A, B, C) or automated guided vehicles, each autonomous mobile robot or automated guided vehicle being able to convey one object (P1, P2, P3, P4, P5) in a conveying line (2; 20) of the system, the method comprising the step of forming a queue (C1, C2), the queue comprising at least two mobile robots (A, B, C) travelling at the same speed along at least one section of the line (2).

2. A conveying method according to claim 1, wherein the queue formation step (C1, C2) is performed in a so-called introduction section (Si) and comprises a grid defining theoretical positions, each of which can be occupied by an autonomous mobile robot, the grid comprising a plurality of parallel tracks (T1, T2, T3) and a plurality of consecutive parallel rows (R1, R2, R3), the plurality of consecutive parallel rows intersecting the tracks and forming a non-zero angle with the tracks, the queue comprising two or more robots (A, B, C) of different rows (R1, R2, R3), the two or more robots being positioned so that two robots of consecutive rows of the same track are separated by a predetermined minimum distance (d).

3. A method according to the preceding claim, wherein the queue formation step includes a sub-step in which two theoretical positions of the same row (R1, R2, R3) and belonging to two adjacent tracks (T1, T2, T3) are offset in the longitudinal direction of the introduction section (Si) by a distance (a), which is equal to the distance between the two adjacent tracks (T1, T2, T3).

4. A method according to the preceding claim, wherein the rows (R1, R2, R3) in the introduction section (Si) form an angle of +45° or -45° with the track (T1, T2, T3), corresponding to the positive orientation or negative orientation of the queue (C1, C2), respectively.

5. A conveying method according to one of claims 2 to 4, wherein a distribution section (Sd1) connected to the introduction section (Si) is added in the conveying line (20), the distribution section (Sd1) having one or more parallel robot entrance tracks (E11, E12, E13) intersecting with several parallel robot exit tracks (S11, S12, S13), and the exit tracks (S11, S12, S13) form a non-zero deflection angle with the robot entrance tracks (E11, E12, E13); the method also includes the step of moving the robots of the queue between the entrance track and the exit track at substantially the same speed.

6. A method according to the preceding claim, wherein an additional distribution section (Sd2) is added to the conveying line, the additional distribution section having one or more parallel second robot entrance tracks (E21, E22, E23) intersecting with one or more parallel second robot exit tracks (S21, S22, S23), the second exit tracks (S21, S22, S23) forming a non-zero deflection angle with the second robot entrance track (E21, E22, E23), and optionally having an orientation opposite to the angle of the distribution section (Sd1), the method also comprising the step of moving the queue between the second entrance track (E21, E22, E23) and at least one of the second exit tracks (S21, S22, S23) at substantially the same speed.

7. A method according to one of claims 5 or 6, comprising a step for changing the orientation of the queue by accelerating and / or decelerating the autonomous mobile robot (A, B, C) in a reorientation area (Zi) provided between two consecutive allocation sections (Sd1, Sd2).

8. A method according to one of claims 5 to 7, wherein when a first robot (A, B) followed by a second robot (B, C) in the same queue on the same entrance track (E11, E12, E13, E21, E22, E23) adopts a first exit track (S12, S13, S22, S23), the second robot (B, C) adopts a second exit track (S11, S12, S21, S22) located before the first exit track.

9. A method according to one of claims 5 to 8, wherein when a robot (A, B) of a first row (R1) and a robot (B, C) of a next row (R2) of the same queue arrive via two parallel entrance tracks and intend to use the same exit track, the robot (A, B) arrives via the first entrance track and the second robot (B, C) then arrives via the second entrance track further away from the exit end of the exit track.

10. The method according to one of the preceding claims, wherein the queue (C1) is spaced apart from a subsequent queue (C2) by a predetermined safety distance (D).

11. A computer program comprising instructions for performing the method according to one of the preceding claims.

12. A computer-readable medium comprising a computer program according to the preceding claim.

13. An internal logistics transportation system, comprising: - a plurality of autonomous mobile robots (A, B, C) or automated guided vehicles, each of which is capable of transporting one object, - a ground transport line (2, 20) in which the autonomous mobile robot / automatic guided vehicle is able to operate, and - Computer program according to claim 11.

14. A plant (100) for sorting objects, comprising a sorting area (101) and a conveyor system according to the preceding claim.

15. An automated object storage facility comprising an object storage area having a plurality of storage levels and a raising and lowering device connecting the levels; the facility further comprising a conveying system according to claim 13.

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