Patent Publication Number: US-2023149978-A1

Title: Transfer device, robot, sorting system, and sorting methods

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Patent Application No. PCT/CN2021/103260 filed on Jun. 29, 2021, which claims priority to Chinese Patent Application No. 202010753970.4 filed on Jul. 30, 2020, which are incorporated herein by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     This application relates to the field of intelligent storage, and in particular, to a transfer device, a robot, a sorting system, and sorting methods. 
     BACKGROUND 
     Intelligent warehousing is an important part of a logistics process. Robots can replace manual labor in moving logistics crates and play an important role in intelligent warehousing. 
     A robot includes a body, and a control device, a pickup device, and multiple storage racks provided on the body. The control device controls movement of the body. Logistics crates on the storage racks are removed from the body (also called loading) or logistics crates are placed on the storage racks on the body (also called unloading) by the pickup device. 
     However, during unloading, the robot needs to remove the logistics crates on the storage racks from the body one by one through the pickup device, resulting in low work efficiency of the robot. 
     SUMMARY 
     This application provides a transfer device, a robot, a sorting system, and sorting methods, which can improve the work efficiency of a robot. 
     In a first aspect, this application provides a transfer device, applied to equipment on which multiple logistics crates can be placed in a first direction, where there are at least two transfer devices provided in the first direction of the equipment, the transfer device includes a supporting base and a first transmission assembly, the first transmission assembly is located on the supporting base, and the first transmission assembly is configured to transport a logistics crate. 
     Optionally, the transfer device provided in this application further includes a first controller and at least one first detection assembly, the first detection assembly is provided on the supporting base, and the first transmission assembly and the first detection assembly are both electrically connected to the first controller; and 
     the first detection assembly is configured to detect whether the logistics crate is at an unsafe position, the first controller is configured to control, in a case that the logistics crate is at an unsafe position, the first transmission assembly to perform transmission in a second direction or a third direction to move the logistics crate to a safe position, and the second direction is opposite to the third direction; 
     where at the unsafe position, the logistics crate partially extends out of the supporting base, or the logistics crate partially extends out of a detection area formed by the first detection assembly. 
     Optionally, in the transfer device provided in this application, at least two first detection assemblies are respectively disposed at two ends of the supporting base. 
     Optionally, in the transfer device provided in this application, the first detection assembly is a reflective photoelectric sensor. 
     Optionally, in the transfer device provided in this application, the first detection assembly is located on the supporting base, and the detection area formed by the first detection assembly covers at least part of the supporting base. 
     Optionally, in the transfer device provided in this application, the first detection assembly is a light curtain sensor. 
     Optionally, in the transfer device provided in this application, the supporting base includes two supports, and the two supports are respectively located on two opposite sides of the first transmission assembly; and 
     each support includes a supporting portion and a blocking edge for blocking the logistics crate, the blocking edge is connected to the supporting portion, the first transmission assembly is fixed to the supporting portion, and the first detection assembly is located on the supporting portion and/or the blocking edge. 
     Optionally, in the transfer device provided in this application, the first transmission assembly is a conveyor belt assembly or a roller transmission assembly. 
     Optionally, in the transfer device provided in this application, the first direction is a height direction of the equipment. 
     In a second aspect, this application provides a robot, including a body and at least two transfer devices provided on the body, where the transfer devices are disposed in a first direction of the body, and each of the transfer devices is the transfer device described above. 
     Optionally, in the robot provided in this application, the body includes a first mobile chassis and at least two first supporting frames provided on the first mobile chassis, and the first mobile chassis is configured to drive the first supporting frames to move; and 
     the first supporting frames extend upward from the first mobile chassis and are perpendicular to the first mobile chassis, and the transfer devices are connected between two adjacent first supporting frames. 
     Optionally, in the robot provided in this application, the transfer devices are disposed at intervals in the first direction of the first supporting frames. 
     In a third aspect, this application provides a sorting system, including at least one conveyor and at least one robot described above, where the conveyor is configured to receive a logistics crate on the robot or transport a logistics crate to the robot. 
     Optionally, in the sorting system provided in this application, the conveyor includes a second supporting frame and at least two first storage layers, the first storage layer is disposed in a first direction of the second supporting frame, and the first storage layer is configured to receive the logistics crate on the robot or transport the logistics crate to the robot. 
     Optionally, in the sorting system provided in this application, the first storage layer is movable between a first position and a second position, the first position is on the second supporting frame, and the second position is at a side of the second supporting frame facing away from the robot. 
     Optionally, in the sorting system provided in this application, a blocking member is provided on the second supporting frame, the blocking member is located at the side of the second supporting frame facing away from the robot, and the blocking member is configured to block at least one of the first storage layers located at an upper part of the second supporting frame. 
     Optionally, in the sorting system provided in this application, each of the first storage layers is the transfer device described above. 
     Optionally, in the sorting system provided in this application, the conveyor includes a third supporting frame, a second transmission assembly located on the third supporting frame, and at least one transfer mechanism; and 
     the transfer mechanism is configured to receive the logistics crate, the second transmission assembly is connected to the transfer mechanism, and the second transmission assembly drives the transfer mechanism to rotate around the third supporting frame, so as to deliver the logistics crate to a lower part of the third supporting frame. 
     Optionally, the sorting system provided in this application further includes at least one unloader, and the unloader is configured to transport the logistics crate between the robot and the conveyor. 
     Optionally, in the sorting system provided in this application, the unloader includes at least two second storage layers, the second storage layer is disposed in the first direction of the unloader, and the unloader transports the logistics crate between the robot and the conveyor through the second storage layer. 
     Optionally, in the sorting system provided in this application, each of the second storage layers is the transfer device described above. 
     Optionally, the sorting system provided in this application further includes at least one elevator, and the elevator is configured to transport the logistics crate between the robot and the conveyor. 
     Optionally, the sorting system provided in this application further includes at least one elevator, and the elevator is configured to transport the logistics crate between the unloader and the conveyor. 
     Optionally, in the sorting system provided in this application, the elevator includes a fourth supporting frame and at least one third storage layer, the third storage layer is disposed in the first direction of the fourth supporting frame and is movable in the first direction of the fourth supporting frame, and the third storage layer is configured to transport the logistics crate. 
     Optionally, in the sorting system provided in this application, the elevator further includes a second mobile chassis, the fourth supporting frame is located on the second mobile chassis, and the second mobile chassis is configured to drive the elevator to move. 
     Optionally, in the sorting system provided in this application, the elevator further includes a second controller and at least one second detection assembly, the second detection assembly is electrically connected to the second controller, the second detection assembly is configured to detect a distance between the third storage layer and an object at a side of the elevator, and the second controller is configured to control, in a case that the distance is less than or equal to a preset value, the third storage layer to stop moving in the first direction. 
     Optionally, in the sorting system provided in this application, the number of the elevator is less than or equal to the number of the conveyor. 
     Optionally, the sorting system provided in this application further includes at least one rack and/or a logistics crate transport assembly, the rack is configured to store the logistics crates on the conveyor, and the logistics crate transport assembly is configured to transport the logistics crates on the conveyor. 
     Optionally, in the sorting system provided in this application, the number of the unloader is the same as the number of the conveyor. 
     In a fourth aspect, this application provides a sorting method, using the sorting system described above. The sorting method includes the following steps: 
     receiving, by the robot, a logistics crate to be sorted; 
     receiving, by the conveyor, the logistics crate on the robot so as to sort the logistics crate on the conveyor. 
     Optionally, the sorting method provided in this application further includes: 
     transporting, by the conveyor, the logistics crate to the robot. 
     In a fifth aspect, this application provides a sorting method, using the sorting system described above. The sorting method includes the following steps: 
     receiving, by the robot, a logistics crate to be sorted; 
     receiving, by the unloader, the logistics crate on the robot, and transporting the logistics crate to the conveyor; and 
     receiving, by the conveyor, the logistics crate on the unloader so as to sort the logistics crate on the conveyor. 
     Optionally, the sorting method provided in this application further includes: 
     transporting, by the conveyor, the logistics crate to the robot through the unloader. 
     In a sixth aspect, this application provides a sorting method, using the sorting system described above. The sorting method includes the following steps: 
     receiving, by the robot, a logistics crate to be sorted; 
     receiving, by the elevator, the logistics crate on the robot, and transporting the logistics crates to the conveyor; and 
     receiving, by the conveyor, the logistics crate on the elevator so as to sort the logistics crate on the conveyor. 
     Optionally, the sorting method provided in this application further includes: 
     transporting, by the conveyor, the logistics crate to the robot through the elevator. 
     In a seventh aspect, this application provides a sorting method, using the sorting system described above. The sorting method includes the following steps: 
     receiving, by the robot, a logistics crate to be sorted; 
     receiving, by the unloader, the logistics crate on the robot, and transporting the logistics crate to the elevator; 
     receiving, by the elevator, the logistics crate on the unloader, and transporting the logistics crate to the conveyor; and 
     receiving, by the conveyor, the logistics crate on the unloader so as to sort the logistics crate on the conveyor. 
     Optionally, the sorting method provided in this application further includes: 
     transporting, by the conveyor, the logistics crate to the robot sequentially through the elevator and the unloader. 
     This application provides a transfer device, a robot, a sorting system, and sorting methods. The transfer device is applied to equipment on which multiple logistics crates are placed in a first direction. The transfer device includes a first transmission assembly. The first transmission assembly moves a logistics crate to a rack or a logistics crate transport assembly corresponding to the equipment. Thus, all logistics crates on the equipment can be simultaneously moved to the rack or the logistics crate transport assembly at a same time, thereby improving the unloading speed of the equipment, reducing the unloading time of the equipment, and improving the work efficiency of the equipment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic structural diagram of a transfer device according to an embodiment of this application. 
         FIG.  2    is an exploded view of a transfer device according to an embodiment of this application. 
         FIG.  3    is a schematic structural diagram of a support and a detection assembly in a transfer device according to an embodiment of this application. 
         FIG.  4    is a schematic structural diagram of a supporting rod in a transfer device according to an embodiment of this application. 
         FIG.  5    is a use state diagram of a transfer device according to an embodiment of this application. 
         FIG.  6    is a top view of  FIG.  5   . 
         FIG.  7    is a schematic structural diagram of a robot according to an embodiment of this application. 
         FIG.  8    is a partial enlarged view of part A in  FIG.  7   . 
         FIG.  9    is a first schematic structural diagram of a sorting system according to an embodiment of this application. 
         FIG.  10    is a first schematic structural diagram of a conveyor in a sorting system according to an embodiment of this application. 
         FIG.  11    is a schematic diagram of the internal structure of part B in  FIG.  10   . 
         FIG.  12    is a second schematic structural diagram of a conveyor in a sorting system according to an embodiment of this application. 
         FIG.  13    is a second schematic structural diagram of a sorting system according to an embodiment of this application. 
         FIG.  14    is a schematic structural diagram of an unloader in  FIG.  13   . 
         FIG.  15    is a third schematic structural diagram of a sorting system according to an embodiment of this application. 
         FIG.  16    is a schematic structural diagram of an elevator in  FIG.  15   . 
         FIG.  17    is a partial enlarged view of part C in  FIG.  16   . 
         FIG.  18    is a use state diagram of a second detection assembly in  FIG.  15   . 
         FIG.  19    is a fourth schematic structural diagram of a sorting system according to an embodiment of this application. 
         FIG.  20    is a side view of  FIG.  19   . 
         FIG.  21    is a top view of  FIG.  19   . 
         FIG.  22    is a schematic structural diagram of a rack in  FIG.  20   . 
         FIG.  23    is a first flowchart of a sorting method according to an embodiment of this application. 
         FIG.  24    is a second flowchart of a sorting method according to an embodiment of this application. 
         FIG.  25    is a third flowchart of a sorting method according to an embodiment of this application. 
         FIG.  26    is a fourth flowchart of a sorting method according to an embodiment of this application. 
     
    
    
     DESCRIPTION OF REFERENCE NUMERALS 
       100 —transfer device;  110 —supporting base;  110   a —first end of supporting base;  110   b —second end of supporting base;  111 ,  111   a ,  111   b —support;  1111 —supporting portion;  1112 —blocking edge;  1113 —bent edge;  1114 —second connection portion;  112 —mounting member;  1121 —mounting portion;  130 —first transmission assembly;  131 —spindle;  132 —conveyor belt;  133 —supporting rod;  134 —supporting plate;  120 ,  120   a ,  120   b —first detection assembly; 
       200 —logistics crate;  200   a —first end of logistics crate;  200   b —second end of logistics crate; 
       300 —robot;  310 —body;  311 —first mobile chassis;  312 —first supporting frame;  3121 —first connection portion;  313 —fork; 
       400 —conveyor;  410 —second supporting frame;  411 —first storage layer;  412 —blocking member;  413 —guide rail;  414 —gear;  415 —rack;  416 —third supporting frame;  417 —transfer mechanism; 
       500 —unloader;  510 —fifth supporting frame;  520 —second storage layer; 
       600 —elevator;  610 —fourth supporting frame;  620 —third storage layer;  630 —second mobile chassis;  640 —second detection assembly; H—distance; 
       700 —rack. 
     DETAILED DESCRIPTION 
     To make the objectives, technical solutions, and advantages of this application clearer, the following describes the technical solutions in the embodiments of this application in more detail with reference to the accompanying drawings in preferred embodiments of this application. In the accompanying drawings, the same or similar components or the components having same or similar functions are denoted by the same or similar reference numerals throughout the description. The described embodiments are only some embodiments rather than all the embodiments of this application. The following embodiments described with reference to the accompanying drawings are exemplary, and are intended to describe this application and cannot be construed as a limitation to this application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of this application without creative efforts fall within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings. 
     In the description of this application, unless otherwise explicitly specified and defined, the terms “mounted”, “connected”, and “connection” are to be understood in a broad sense, for example, the connection may be a fixed connection, an indirect connection through an intermediary, internal communication between two elements, or an interaction relationship between two elements. A person of ordinary skill in the art may understand specific meanings of the terms in this application according to specific situations. 
     In the description of this application, it is to be understood that, orientations or position relationships indicated by terms such as “up”, “down”, “front”, “rear”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, and “outer” are orientations or position relationships shown based on the accompanying drawings, and are used only for ease of describing this application and simplifying the description, rather than indicating or implying that the device or element has a particular orientation or is constructed and operated in a particular orientation, and therefore, cannot be construed as a limitation to this application. 
     In the description, claims, and accompanying drawings of this application, the terms “first”, “second”, and “third” (if present) are intended to distinguish similar objects but do not necessarily indicate a specific order or sequence. It is to be understood that such used data is interchangeable where appropriate so that the embodiments of this application described here can be implemented, for example, in an order other than those illustrated or described here. 
     Moreover, the terms “include”, “have” and any other variants are intended to cover the non-exclusive inclusion, for example, a process, method, system, product, or display that includes a list of steps or units is not necessarily limited to those expressly listed steps or units, but may include other steps or units not expressly listed or inherent to such a process, method, system, product, or display. 
     Robots can replace manual labor in moving logistics crates and play an important role in intelligent warehousing. A robot includes a body, and a control device, a pickup device, and multiple storage racks provided on the body. The control device controls movement of the body. Logistics crates on the storage racks are removed from the body (also called loading) or logistics crates are placed on the storage racks on the body (also called unloading) by the pickup device. However, during unloading, the robot needs to remove the logistics crates on the storage racks from the body one by one through the pickup device, resulting in low work efficiency of the robot. Thus, embodiments of this application provide a transfer device, a robot, a sorting system, and sorting methods, which can improve the work efficiency of a robot. 
     This application will be described in detail below with reference to the accompanying drawings and specific embodiments. 
     Embodiment 1 
       FIG.  1    is a schematic structural diagram of a transfer device according to an embodiment of this application.  FIG.  2    is an exploded view of a transfer device according to an embodiment of this application.  FIG.  3    is a schematic structural diagram of a support and detection assemblies in a transfer device according to an embodiment of this application.  FIG.  4    is a schematic structural diagram of a supporting rod in a transfer device according to an embodiment of this application.  FIG.  5    is a use state diagram of a transfer device according to an embodiment of this application. 
       FIG.  6    is a top view of  FIG.  5   .  FIG.  7    is a schematic structural diagram of a robot according to an embodiment of this application.  FIG.  8    is a partial enlarged view of part A in  FIG.  7   . With reference to  FIG.  1    to  FIG.  8   , this application provides a transfer device  100 , applied to equipment on which multiple logistics crates  200  can be placed in a first direction. There are at least two transfer devices  100  provided in the first direction of the equipment. The first direction may be a height direction of the equipment. 
     The transfer device  100  includes a supporting base  110  and a first transmission assembly  130 . The first transmission assembly  130  is located on the supporting base  110 . The first transmission assembly  130  transports a logistics crate  200 . 
     In this application, the equipment on which multiple logistics crates  200  can be placed in the first direction may be equipment used in the art for transporting logistics crates, such as a robot  300 , an unloader  500 , or a conveyor  400 . For the convenience of depiction, the description in this application is given by providing at least two transfer devices  100  on the robot  300  in the first direction, that is, the robot  300  can be provided with at least two transfer devices  100  in the height direction. A logistics crate  200  can be placed on each of the transfer devices  100 . 
     The sizes and packaging of goods are different. In order to facilitate transportation of goods, the goods can be placed in a logistics crate  200 , and the logistics crate  200  is placed on the first transmission assembly  130  to transport the logistics crate  200 . One or more logistics crates  200  can be placed on the first transmission assembly  130 . When the goods have outer packaging and the size thereof is close to or equal to the size of the logistics crate  200 , the goods can be directly placed on the first transmission assembly  130  for transportation. 
     The first transmission assembly  130  is configured to transport the logistics crate  200 . When the robot  300  loads goods, the logistics crates  200  are placed one by one into the multiple transfer devices  100  provided on the robot  300  through a pickup device such as a fork  313  on the robot  300 . At least one logistics crate  200  can be placed in each of the transfer devices  100 , and at least one piece of goods can be placed in one logistics crate  200 . This can be selected according to actual situations, and is not limited in this application. 
     When the robot  300  unloads goods, the robot  300  moves to a position where the goods need to be unloaded, for example, the robot  300  moves to a rack or the conveyor  400 . The rack or the conveyor  400  is provided with a storage layer opposite to the transfer device  100 . The first transmission assembly  130  synchronously perform transmission in the +Y direction or the −Y direction in  FIG.  1    to move the logistics crate  200  to the storage layer opposite thereto, so that all the logistics crates  200  on the robot  300  can be simultaneously moved to the storage layers at a same time, thereby improving the unloading speed of the robot  300 , reducing the unloading time of the robot  300 , and improving the work efficiency of the robot  300 . The logistics crates  200  on the storage layers can also be simultaneously returned to the transfer devices  100  on the robot  300 , thereby improving the loading efficiency of the robot  300 . 
     With continuing reference to  FIG.  1    to  FIG.  6   , the transfer device  100  further includes a first controller (not shown) and at least one first detection assembly  120 , the first detection assembly  120  is provided on the supporting base  110 , and the first transmission assembly  130  and the first detection assembly  120  are both electrically connected to the first controller. The first detection assembly  120  is configured to detect whether the logistics crate  200  is at an unsafe position. The first controller is configured to control, in a case that the logistics crate  200  is at an unsafe position, the first transmission assembly  130  to perform transmission in a second direction or a third direction to move the logistics crate  200  to a safe position. The second direction is opposite to the third direction. For convenience of depiction, the second direction may be the +Y direction in  FIG.  1   , and the third direction may be the −Y direction in  FIG.  1   . 
     At the unsafe position, the logistics crate  200  partially extends out of the supporting base  110 , or the logistics crate  200  partially extends out of a detection area formed by the first detection assembly  120 . 
     Specifically, the supporting base  110  is used for supporting the first transmission assembly  130 , and the length of the supporting base  110  in the second direction is equal to the length of the first transmission assembly  130  in the second direction, or the difference between the length of the supporting base  110  in the second direction and the length of the first transmission assembly  130  in the second direction is less than or equal to 50 mm, thereby making it convenient for the first detection assembly  120  to detect whether the logistics crate  200  is located at an unsafe position. The first controller may be provided on the supporting base  110 . Thus, it is convenient to electrically connect the first transmission assembly  130  to the first controller, and to mount the first controller. In some embodiments, the first controller may also be disposed on another position of the robot  300 . The position of the first controller is not limited in this application. 
     During the process that the robot  300  moves to a position where goods need to be unloaded, or during other movements, the logistics crate  200  may move on the first transmission assembly  130  due to vibration and other reasons, and thus is at a risk of falling from the transfer device  100 . Therefore, in this application, the transfer device  100  further includes a first controller and at least one first detection assembly  120 . The first detection assembly  120  detects whether the logistics crate  200  is at an unsafe position. In a case that the first detection assembly  120  detects that the logistics crate  200  is at an unsafe position, the first controller controls the first transmission assembly  130  to perform transmission in the +Y direction or −Y direction in FIG.  1  to move the logistics crate  200  to a safe position. Thus, the logistics crate  200  is prevented from falling from the transfer device  100  during movement of the robot  300 . 
     In some embodiments, the number of the first detection assembly  120  is at least two, and the at least two first detection assemblies  120  are respectively disposed on two ends of the supporting base  110 . When a first end  200   a  of the logistics crate moves to a first end  110   a  of the supporting base, the logistics crate  200  tends to extend out of the supporting base  110 , and the first of the first detection assemblies  120   a  can detect the logistics crate  200 . In this case, the first controller may control the first transmission assembly  130  to perform transmission in the −Y direction, so as to move the logistics crate  200  toward a second end  110   b  of the supporting base, thereby moving the logistics crate  200  into the supporting base  110 . When a second end  200   b  of the logistics crate moves to the second end  110   b  of the supporting base, the second of the first detection assemblies  120   b  can detect the logistics crate  200 . In this case, the first controller may control the first transmission assembly  130  to perform transmission in the +Y direction, so as to move the logistics crate  200  toward the first end  110   a  of the supporting base, thereby moving the logistics crate  200  into the supporting base  110 . Thus, the logistics crate  200  can be prevented from falling from the transfer device  100 . 
     The first detection assembly  120  may be a reflective photoelectric sensor. The reflective photoelectric sensor is not affected by the shape, color, and material of an object to be detected, and is easy to mount. 
     The detection timing for the first detection assembly  120  to detect whether the logistics crate  200  is located at an unsafe position may be during a process that the robot  300  moves to a position where goods needs to be unloaded, or during other movements. When the robot  300  is in a stationary state or in the process of transporting the logistics crate  200 , the first detection assembly  120  may stop detection operation. 
     In another embodiment, the number of the first detection assembly  120  may be one, the first detection assembly  120  may be located on the supporting base  110 , and a detection area formed by the first detection assembly  120  covers at least part of the supporting base  110 . The first detection assembly  120  may be a light curtain sensor. The detection area formed by the light curtain sensor matches the logistics crate  200 . When the logistics crate  200  partially extends out of the detection area formed by the first detection assembly  120 , the first controller may control the first transmission assembly  130  to perform transmission in the −Y direction or the +Y direction, so as to make the logistics crate  200  located in the detection area formed by the detection assembly  120 . Thus, the logistics crate  200  can be prevented from falling from the transfer device  100 . 
     With continuing reference to  FIG.  1    to  FIG.  3   , in the transfer device provided in this application, the supporting base  110  includes two supports  111 , and the two supports  111  are respectively located on two opposite sides of the first transmission assembly  130 . 
     Each support  111  includes a supporting portion  1111  and a blocking edge  1112  for blocking the logistics crate  200 . The blocking edge  1112  is connected to the supporting portion  1111 , and the blocking edge  1112  is located above the supporting portion  1111 . The first transmission assembly  130  is fixed to the supporting portion  1111 . The first detection assembly  120  is located on the supporting portion  1111  and/or the blocking edge  1112 . 
     In the transfer device provided in this application, the first transmission assembly  130  is a conveyor belt assembly or a roller transmission assembly. The conveyor belt assembly may include a motor (not shown), two spindles  131 , and a conveyor belt  132  sleeved on the spindles  131 . The logistics crate  200  is located on the conveyor belt  132 . The two ends of each spindle  131  are respectively rotatably connected to the two supporting portions  1111 . There may be one motor, and the motor is connected to any of the spindles  131 . The spindle  131  is driven to rotate forwardly or backwardly by the motor, so as to drive the logistics crate  200  on the conveyor belt  132  to move in the +Y direction or the −Y direction in  FIG.  5   . Alternatively, the two spindles  131  are each connected to a motor, one motor drives the spindle  131  connected thereto to forwardly rotate, and the other motor drives the spindle  131  connected thereto to backwardly rotate, so as to drive the logistics crate  200  on the conveyor belt  132  to move. 
     If the logistics crate  200  is heavy and the conveyor belt  132  cannot support the logistics crate  200 , the logistics crate  200  on the conveyor belt  132  may be caused to move at a reduced speed or be difficult to move smoothly. Therefore, in some embodiments, supporting rods  133  are connected between the two supports  111 , the supporting rods  133  are located in an area enclosed by the conveyor belt  132 , and the conveyor belt  132  is supported by the supporting rods  133 . In order to increase the supporting area, a supporting plate  134  can be connected onto the supporting rods  133 , and the conveyor belt  132  is supported by the supporting plate  134 . 
     In this application, an anti-skid layer may be provided on the conveyor belt  132 , and the anti-skid layer can increase the static friction between the logistics crate  200  and the surface of the conveyor belt  132  to prevent the logistics crate  200  from sliding on the conveyor belt  132 . The anti-skid layer may be an anti-skid pattern provided on the surface of the conveyor belt  132  (the contact surface between the conveyor belt  132  and the logistics crate  200 ), or an uneven structure provided on the surface of the conveyor belt  132 , or an anti-skid layer well known to a person skilled in the art, which is not limited in this embodiment. 
     In some embodiments, the first transmission assembly  130  may be a roller transmission assembly. The roller transmission assembly may include at least one driving member and multiple spindles  131 . Two ends of each spindle  131  are respectively rotatably connected to the two supporting portions  1111 , and at least one spindle  131  is connected to the driving member. The logistics crate  200  is placed on the spindles  131 , and the spindles  131  are driven to rotate by the driving member, so as to move the logistics crate  200  in the +Y direction or the −Y direction. An anti-skid sleeve can be provided on each spindle  131 . The static friction between the logistics crate  200  and the surfaces of the spindles  131  is increased through the anti-skid sleeves to prevent the logistics crate  200  from sliding on the spindles  131 . 
     In order to facilitate mounting of the first detection assembly  120 , in the transfer device provided in this application, the supporting base  110  further includes at least two mounting members  112 . The at least two mounting members  112  are respectively connected to two opposite ends of the supporting base  110 . Each mounting member  112  is provided with a mounting portion  1121 , and the first detection assembly  120  is located on the mounting portion  1121 . 
     Two ends of at least one support  111  are each connected to a mounting member  112 ; or two ends of one of the two supports  111  are each connected to a mounting member  112 ; or, a first end of one support  111   a  is connected to a mounting member  112 , and a second end of the other support  111   b  is connected to a mounting member  112 ; or, a second end of the support  111   a  is connected to a mounting member  112 , and a first end of the other support  111   b  is connected to a mounting member  112 . As long as it is ensured that the at least two first detection assemblies  120  are respectively disposed at the two ends of the supporting base  110 . 
     The logistics crate  200  is moved on the first transmission assembly  130 . In order to avoid collision between the logistics crate  200  and the first detection assembly  120 , in a specific implementation, the mounting portion  1121  is an accommodating groove, the first detection assembly  120  is accommodated in the accommodating groove, and a detection end of the first detection assembly  120  faces the first transmission assembly  130 . 
     Exemplarily, a sensing surface of the reflective photoelectric sensor faces the first transmission assembly  130 . The first detection assembly  120  may also be a travel switch. The travel switch may be located on the first transmission assembly  130  or on the mounting portion  1121 , as long as the travel switch can detect movement of the logistics crate  200  relative to the first transmission assembly  130  when the first transmission assembly  130  is in a stationary state. No limitation is made thereto in this embodiment. 
     Further, in the transfer device provided in this application, two ends of the blocking edge  1112  are provided with bent edges facing away from the first transmission assembly  130 , so as to increase the opening size of the exit and the entry of the transfer device  100 , thereby achieving a guiding function for the logistics crate  200  to enter the first transmission assembly  130  and exit the first transmission assembly  130 . 
     The mounting portion  1121  is flush with the inner side of a corresponding bent edge  1113  or is located outside the corresponding bent edge  1113 . In this way, collision between the logistics crate  200  and the first detection assembly  120  can be avoided. The height of the bent edge  1113  (the +X direction in  FIG.  1   ) may be greater or less than the height of the mounting portion  1121  (the +X direction in  FIG.  1   ), as long as the first detection assembly  120  is higher than the bent edge  1113 . 
     Embodiment 2 
     With continuing reference to  FIG.  1    to  FIG.  8   , this application further provides a robot  300 , including a body  310  and at least one transfer device  100  provided on the body  310 . The transfer device  100  is the transfer device  100  according to any one of the foregoing embodiments. 
     The structure of the transfer device  100  is described in detail in the above embodiments, and no repeated description is provided herein. 
     A pickup device may also be provided on the robot  300 , and the pickup device is configured to move the logistics crate  200  to the transfer device  100 . The pickup device may be a pickup device commonly used in the art, such as a robotic arm, a clamping fork, or a claw, which is not limited in this application. In  FIG.  7    of this embodiment, a fork  313  is taken as the pickup device for description. 
     In order to facilitate movement of the robot  300 , during specific implementation, the body  310  includes a first mobile chassis  311  and at least two first supporting frames  312  provided on the first mobile chassis  311 , and the first mobile chassis  311  is configured to drive the first supporting frames  312  to move. 
     The first supporting frames  312  extend upward from the first mobile chassis  311  and are perpendicular to the first mobile chassis  311 , and the transfer devices  100  are connected between two adjacent first supporting frames  312 . 
     The transfer devices  100  are disposed at intervals in a first direction of the first supporting frames  312  (i.e., the height direction of the first supporting frames  312 ). The distance between two adjacent transfer devices  100  may be the same or different. For example, the distance between two adjacent transfer devices  100  increases or decreases sequentially in the height direction of the first mobile chassis  311 . Thus, logistics crates  200  of different specifications can be placed. 
     In some embodiments, the mounting positions of the transfer devices  100  are adjustable, so that the distances between the transfer devices  100  can be adjusted according to the specifications of the logistics crates  200 . For example, multiple first through holes are provided at intervals in the height direction of each first supporting frame  312 , and the transfer devices  100  are connected to the through holes by bolts to adjust the distances between the transfer devices  100 . 
     In order to facilitate mounting of the transfer device  100  on the body  310 , in the robot provided in this application, each first supporting frame  312  is provided with at least one first connection portion  3121  in the first direction, the supporting base  110  is provided with a second connection portion  1114 , the transfer device  100  and the first supporting frame  312  are detachably connected through the first connection portion  3121  and the second connection portion  1114 . 
     In a specific implementation, one of the first connection portion  3121  and the second connection portion  1114  is first connection holes, and the other is a connection seat. The connection seat is provided with second through holes, and screws are connected to the first connection holes through the second through holes on the connection seat, so as to detachably connect the transfer device  100  to the first supporting frame  312 . Alternatively, the first connection portion  3121  is snap-fit to the second connection portion  1114 . One of the first connection portion  3121  and the second connection portion  1114  is a slot, and the other is a fastener matching the slot. Alternatively, the transfer devices  100  are connected to the first supporting frames  312  in a detachable connection manner well known to a person skilled in the art to adjust the distances between the transfer devices  100 . No limitation thereto is made herein. 
     The second connection portion  1114  may be located on the supporting portion  1111 , and the supporting portion  1111  is a main load-bearing portion of the supporting base  110 . Thus, the reliability of the connection between the transfer devices  100  and the body  310  is increased. 
     Embodiment 3 
       FIG.  9    is a first schematic structural diagram of a sorting system according to an embodiment of this application. With reference to  FIG.  1    to  FIG.  9   , the sorting system provided in this application includes at least one conveyor  400  and at least one robot  300  according to any one of the foregoing embodiments. The conveyor  400  is configured to receive a logistics crate  200  on the robot  300 , or to transport a logistics crate  200  on the conveyor  400  to the robot  300 . 
     The structure of the robot  300  is described in detail in the above embodiments, and no repeated description is provided herein. 
     Possible implementation structures of the conveyor  400  will be described below through different embodiments. 
       FIG.  10    is a first schematic structural diagram of a conveyor in a sorting system according to an embodiment of this application.  FIG.  11    is a schematic diagram of the internal structure of part B in  FIG.  10   . With reference to  FIG.  10    and  FIG.  11   , in the sorting system provided in this application, the conveyor  400  includes a second supporting frame  410  and at least two first storage layers  411  located on the second supporting frame  410 . The first storage layer  411  is disposed in a first direction of the second supporting frame  410  (i.e., the height direction of the second supporting frame  410 ), and the first storage layer  411  is configured to receive a logistics crate  200  on the robot  300  or transport a logistics crate  200  to the robot  300 . The second supporting frame  410  may be a cuboid frame, and the first storage layers  411  are located in the second supporting frame  410 . 
     Optionally, the first storage layer  411  is provided in one-to-one correspondence to the transfer device  100  on the robot  300 . When the robot  300  moves to the conveyor  400 , the transfer device  100  on the robot  300  simultaneously move the logistics crate  200  to the first storage layer  411  opposite thereto through transmission by the first transmission assembly  130 , and an operator sorts the logistics crate  200  on the first storage layer  411  of the conveyor  400 . In this way, direct contact between the operator and the robot  300  is avoided, the unloading speed of the robot  300  is increased, the unloading time of the robot  300  is reduced, and the work efficiency of the robot  300  is improved. 
     In order to facilitate sorting of goods in the logistics crate  200  by the operator, in the sorting system provided in this application, each first storage layer  411  can be moved between a first position and a second position. The first position is on the second supporting frame  410 , and the second position is at the side of the second supporting frame  410  facing away from the robot  300 . That is, the first storage layer  411  can move toward the side facing away from the robot  300  to the outside of the second supporting frame  410 . In this way, the operator can directly perform an operation of sorting the goods in the logistics crate  200  moving along with the first storage layer  411  to the outside of the second supporting frame  410 . It is convenient for the operator to sort the goods in the logistics crate  200 . 
     In some embodiments, one or two first storage layers  411  in the lower part of the second supporting frame  410  can be moved between the first position and the second position. In this way, the operator can stand to sort the goods at a comfortable height that can be reached, without squatting or climbing, thereby increasing comfort of the operator during work. 
     In this application, the heights of some first storage layers  411  located at the upper part of the second supporting frame  410  may exceed the height of the operator, which is inconvenient for the operator to sort the goods. Therefore, the some first storage layers  411  can be used as temporary logistics crate placement positions for temporarily placing the logistics crates  200 . When sorting of goods in the logistics crate  200  on the first storage layer  411  at the lower part of the second supporting frame  410  is completed, the logistics crates  200  at the temporary logistics crate storage positions can be moved to the first storage layer  411  at the lower part of the second supporting frame  410 . 
     In some embodiments, a blocking member  412  is provided on the second supporting frame  410 , the blocking member  412  is located at the side of the second supporting frame  410  facing away from the robot  300 , and the blocking member  412  is configured to block at least one first storage layer  411  located at the upper part of the second supporting frame  410 . By using the blocking member  412  to block at least one first storage layer  411  located at the upper part of the second supporting frame  410 , the logistics crate  200  on the first storage layer  411  at the upper part of the second supporting frame  410  is prevented from falling to the operator side, thereby increasing the safety of the operator during work. 
     The boundary between the upper part of the second supporting frame  410  and the lower part of the second supporting frame  410  can be configured according to the comfortable height for the operator to work. When the operator needs to use an auxiliary tool such as a step stool or a ladder to sort the logistics crate  200  in a first storage layer  411 , the second supporting frame  410  at the height and above can be defined as the upper part of the second supporting frame  410 . 
     In order to make it convenient for the first storage layer  411  to extend out of the second supporting frame  410 , in one embodiment, a guide rail  413  is provided on the second supporting frame  410 , and the guide rail  413  may extend toward the outside of the second supporting frame  410 . Two guide rails  413  may be provided horizontally, and the first storage layer  411  is connected between the two guide rails  413 . The guide rail  413  having a guiding function for movement of the first storage layer  411 , so that the first storage layer  411  can smoothly extend out of the second supporting frame  410 . 
     Implementations in which the first storage layer  411  extends out of the second supporting frame  410  will be described below. 
     In a possible implementation, the first storage layer  411  is slidably connected to the guide rail  413  and slides in the extension direction of the guide rail  413 . For example, the guide rail  413  is provided with a groove, the first storage layer  411  is provided with a protrusion, and the protrusion is inserted into the groove to slidably connect the first storage layer  411  to the guide rail  413 . Alternatively, a slidable connection manner well known to a person skilled in the art may be used. 
     In another possible implementation, a driving structure is provided on the second supporting frame  410 , and the driving structure is connected to the first storage layer  411  to drive the first storage layer  411  to extend out of the second supporting frame  410 . Specifically, the driving structure may include a motor, a gear  414 , and a rack  415  meshed with the gear  414 . The rack  415  is located on the guide rail  413 . The motor drives the gear  414  to rotate forwardly or backwardly, so as to drive the gear  414  to move along the rack  415 , and then drive the first storage layer  411  connected to the rack  415  to extend out of the second supporting frame  410  or retreat into the second supporting frame  410 . 
     Implementations in which the first storage layer  411  extends out of the second supporting frame  410  are not limited to the above two. In a specific implementation, the above two manners can be combined so that the first storage layer  411  can extend out of the second supporting frame  410 . Alternatively, the structure of a slidable drawer in the related art can be used so that the first storage layer  411  can extend out of the second supporting frame  410 . No limitation thereto is made in this embodiment. 
     In some embodiments, the first storage layer  411  is the transfer device  100  provided in the foregoing embodiments. 
       FIG.  12    is a second schematic structural diagram of a conveyor in a sorting system according to an embodiment of this application. With reference to  FIG.  12   , in the sorting system provided in this application, the conveyor  400  includes a third supporting frame  416 , a second transmission assembly (not shown), and at least one transfer mechanism  417 . 
     The transfer mechanism  417  is configured to receive a logistics crate  200 , the second transmission assembly is connected to the transfer mechanism  417 , and the second transmission assembly drives the transfer mechanism  417  to rotate around the third supporting frame  416 , so as to deliver the logistics crate  200  to a lower part of the third supporting frame  416 . 
     The division mode of the upper part of the third supporting frame  416  and the lower part of the third supporting frame  416  is the same as the division mode of the upper part of the second supporting frame  410  and the lower part of the second supporting frame  410  in the foregoing embodiments. Reference may be made to the division mode of the upper part of the second supporting frame  410  and the lower part of the second supporting frame  410  described above, and will not be repeated here. No repeated description is provided herein. 
     Specifically, the second transmission assembly includes a driving member, a driving wheel, a driven wheel, and pulleys. The transfer mechanisms  417  are connected to the pulleys at intervals. The driving wheel and the driven wheel are connected through the pulleys. The pulleys can be arranged in a racetrack shape to rotate around the third supporting frame  416 , so as to drive the transfer mechanisms  417  to rotate around the third supporting frame  416 . The driving wheel is connected to the driving member, and the driving member drives the pulleys to rotate through the driving wheel, so as to deliver the logistics crates  200  to the lower part of the third supporting frame  416 . 
     The transfer mechanism  417  may be the transfer device  100  provided in the foregoing embodiments, or the transfer mechanism  417  may be a toothed supporting structure shown in  FIG.  13   . No limitation thereto is made in this embodiment. 
     Embodiment 4 
       FIG.  13    is a second schematic structural diagram of a sorting system according to an embodiment of this application.  FIG.  14    is a schematic structural diagram of an unloader in  FIG.  13   . On the basis of embodiment  3  above, with reference to  FIG.  13    and  FIG.  14   , the sorting system provided in this application further includes at least one unloader  500 . The unloader  500  is configured to transport logistics crates  200  between a robot  300  and a conveyor  400 . In this case, the structure of the conveyor  400  in the implementation shown in  FIG.  12    described above is used. 
     The unloader  500  includes at least two second storage layers  520 , the second storage layer  520  is disposed in a first direction of the unloader  500  (i.e., the height direction of the unloader  500 ), and the unloader  500  transports the logistics crate  200  between the robot  300  and the conveyor  400  through the second storage layer  520 . 
     In a specific implementation, the unloader  500  further includes a fifth supporting frame  510 , and the second storage layer  520  is located on the fifth supporting frame  510 . The second storage layer  520  is supported by the fifth supporting frame  510 . The fifth supporting frame  510  may be a rectangular frame, and the second storage layer  520  is located in the fifth supporting frame  510 . 
     By providing the unloader  500 , the logistics crate  200  on the robot  300  can be temporarily stored on the unloader  500 , thereby reducing the unloading time of the robot  300 . Thus, the robot  300  can be released, so that the robot  300  can perform other tasks, thereby further improving the operation efficiency of the robot  300 . Alternatively, the logistics crate  200  on the conveyor  400  is transported to the robot  300  through the unloader  500 . 
     In order to timely move the logistics crate  200  on the robot  300  to the unloader  500 , in some embodiments, the second storage layer  520  is in one-to-one correspondence to the transfer device  100  on the robot  300 . The second storage layer  520  is configured to transfer the logistics crate  200  on the transfer devices  100  of the robot  300  to the conveyor  400  at a same time. The transfer mechanism  417  may be in one-to-one correspondence to the second storage layer  520 . The logistics crate  200  is transported to the transfer device  100  of the robot  300  sequentially through the transfer mechanism  417  and the second storage layer  520  at a same time. 
     In order to facilitate transfer of the logistics crate  200  on the unloader  500  to the conveyor  400 , or to the robot  300 , the second storage layer  520  may be the transfer device  100  provided in the foregoing embodiments. 
     Embodiment 5 
       FIG.  15    is a third schematic structural diagram of a sorting system according to an embodiment of this application.  FIG.  16    is a schematic structural diagram of an elevator in  FIG.  15   .  FIG.  17    is a partial enlarged view of part C in  FIG.  16   .  FIG.  18    is a use state diagram of a second detection assembly in  FIG.  15   . On the basis of embodiment 3 above, with reference to  FIG.  15    to  FIG.  18   , the sorting system further includes at least one elevator  600 . The elevator  600  is configured to transport a logistic crates  200  between a robot  300  and a conveyor  400 . Specifically, the elevator  600  receives the logistics crate  200  on the robot  300  and transports the logistics crate  200  to the conveyor  400 , or the elevator  600  receives the logistics crate  200  on the conveyor  400  and transports the logistics crate  200  to the robot  300 . 
     The elevator  600  includes a fourth supporting frame  610  and at least two third storage layers  620 . The third storage layer  620  is disposed in a first direction of the fourth supporting frame  610  (i.e., the height direction of the fourth supporting frame  610 ), and the third storage layer  620  can move in the first direction of the fourth supporting frame  610  (i.e., moving up and down in the height direction of the fourth supporting frame  610 ). The third storage layer  620  is used for placing the logistics crate  200 . In a specific implementation, the elevator  600  may be provided with a timing belt assembly or a chain assembly, and the third storage layer  620  is driven to move in the first direction of the fourth supporting frame  610  by the timing belt assembly or the chain assembly. The third storage layer  620  may be the transfer device  100  provided in the foregoing embodiments. 
     When the conveyor  400  has the structure shown in  FIG.  12   , the elevator  600  may be omitted, and the sorting system may include the robot  300  and the conveyor  400 . 
     In order to facilitate movement of the elevator  600  between the robot  300  and the conveyor  400 , the elevator  600  further includes a second mobile chassis  630 . The fourth supporting frame  610  is located on the second mobile chassis  630 , and the second mobile chassis  630  is configured to drive the elevator  600  to move. 
     In this application, the third storage layer  620  can move up and down in the height direction of the fourth supporting frame  610 , that is, the third storage layer  620  can be lifted and lowered cyclically. By the cyclic lifting and lowering of the third storage layer  620  of the elevator  600 , the sorted logistics crate  200  on the first storage layer  411  at the lower part of the conveyor  400  can be transported to the robot  300 , or transported to the first storage layer  411  at the upper part of the conveyor  400  for temporary storage. By the cyclic lifting and lowering of the third storage layer  620  of the elevator  600 , the logistics crate  200  that is not sorted at the upper part of the conveyor  400  can also be transported to the first storage layer  411  at the lower part of the conveyor  400  for sorting. 
     In some embodiments, the elevator  600  further includes a second controller (not shown) and at least one second detection assembly  640 . The second detection assembly  640  is electrically connected to the second controller. The second detection assembly  640  is configured to detect a distance H between the third storage layer  620  and an object at a side of the elevator  600 . The second controller is configured to control, in a case that the distance H is less than or equal to a preset value, the third storage layer  620  to stop moving in the first direction. 
     The object at the side of the elevator  600  may be a logistics crate  200  at an unsafe position on the robot  300  and/or a logistics crate  200  at an unsafe position on the conveyor  400  shown in  FIG.  18   . 
     In this application, a detection surface of the second detection assembly  640  faces a first end in the first direction and a second end in a second direction, respectively. When there is one third storage layer  620 , at least one second detection assembly  640  may be connected to each of the upper surface and the lower surface of the third storage layer  620 . When there are two or more third storage layers  620 , at least one second detection assembly  640  may be connected to each of the upper surface of the third storage layer  620  at the first end in the first direction (the uppermost third storage layer  620  in  FIG.  18   ) and the lower surface of the third storage layer  620  at the second end in the first direction (the lowermost third storage layer  620  in  FIG.  18   ). The second detection assembly  640  detects whether the third storage layer  620  will collide with the logistics crate  200  at the unsafe position on the robot  300  and/or the logistics crate  200  at the unsafe position on the conveyor  400  during the upward/downward movement of the third storage layer  620  in the height direction of the fourth supporting frame  610 . 
     The preset value is a safety distance between the third storage layer  620  and the logistics crate  200  located at the unsafe position on the robot  300  and/or the logistics crate  200  located at the unsafe position on the conveyor  400 . That is, when the distance is less than or equal to the safety distance, the third storage layer  620  is controlled to stop moving up/down to prevent the third storage layer  620  from colliding with the logistics crate  200  at the unsafe position on the robot  300  and/or the logistics crate  200  at the unsafe position on the conveyor  400 . 
     The sorting system may include a master controller to which the first and second controllers are connected. In this application, when the distance H is less than or equal to the preset value, the second controller controls the third storage layer  620  to stop moving in the first direction, and the first controller controls the transfer device  100  to transmit the logistics crate  200  in the second direction or the third direction, so as to move the logistics crate  200  to a safe position. In this case, the second controller  640  controls the third storage layer  620  to move in the first direction. 
     In some embodiments, the angle of the second detection assembly  640  is adjustable. By adjusting the angle of the second detection assembly  640 , the detection surface of the second detection assembly  640  can detect the logistics crate  200  at the unsafe position and/or the logistics crate  200  at the unsafe position on the conveyor  400 . An angle adjustment structure commonly used by a person skilled in the art may be adopted, which is not limited in this embodiment. 
     The second detection assembly  640  may be a gap sensor. 
     In this application, since the elevator  600  includes the second mobile chassis  630 , the second mobile chassis  630  can drive the elevator  600  to move, so that the elevator  600  moves between the conveyor  400  and the robot  300  to transport the logistics crates  200 . That is, one elevator  600  may correspond to at least one conveyor  400  and at least one robot  300 . In this way, the number of the elevator  600  may be less than or equal to the number of the conveyor  400 . 
     Embodiment 6 
       FIG.  19    is a fourth schematic structural diagram of a sorting system according to an embodiment of this application.  FIG.  20    is a side view of  FIG.  19   .  FIG.  21    is a top view of  FIG.  19   . On the basis of embodiment 4 above, with reference to  FIG.  19    to  FIG.  21   , the sorting system further includes at least one elevator  600 . That is, the sorting system includes a robot  300 , an unloader  500 , the elevator  600 , and a conveyor  400 . The elevator  600  is configured to transfer a logistics crate between the unloader  500  and the conveyor  400 . 
     In this application, the structure and working principle of the elevator  600  are the same as those in an embodiment 5, and no repeated description is provided herein. 
     In this application, after the unloader  500  receives the logistics crate  200  on the robot  300 , the elevator  600  receives the logistics crate  200  on the unloader  500  and transports the logistics crate  200  to the conveyor  400 . Alternatively, the elevator  600  receives the logistics crate  200  on the conveyor  400  and transports the logistics crate  200  to the unloader  500 , and the unloader  500  transports the logistics crate  200  to the robot  300 . 
     An object at a side of the elevator  600  may be at least one of a logistics crate  200  at an unsafe position on the unloader  500  or a logistics crate  200  at an unsafe position on the conveyor  400 . The second detection assembly  640  detects whether the third storage layer  620  will collide with the logistics crate  200  at the unsafe position on the unloader  500  or the logistics crate  200  at the unsafe position on the conveyor  400  during upward/downward movement of the third storage layer  620  in the height direction of the fourth supporting frame  610 . The detection mode of the second detection assembly  640  is the same as that in an embodiment 5, and no repeated description is provided herein. 
       FIG.  22    is a schematic structural diagram of a rack in  FIG.  20   . With reference to  FIG.  20    and  FIG.  22   , the sorting system provided in this application further includes at least one rack  700  and/or a goods transport assembly. The rack  700  is used for storing the logistics crate  200  in the conveyor  400 . The rack  700  is used for placing the logistics crate  200 . The goods transport assembly is configured to transport the logistics crate  200  in the conveyor  400 . 
     At least one of embodiment 3 to embodiment 5 above may include at least one rack  700  and/or a goods transport assembly. 
     The number of the robot  300 , the number of the unloader  500 , and the number of the conveyor  400  may be the same. In  FIG.  21   , description is made by taking the number of the robot  300  being six and the number of the elevator  600  being two as an example. In some embodiments, the number of the robot  300  is less than the number of the unloader  500 , thereby ensuring that the robot  300  can timely transport the logistics crate  200  thereon to the unloader  500  to avoid occupation of the robot  300 . The number of the unloader  500  may be the same as the number of the conveyor  400 . 
     In the sorting system provided in this application, the elevator  600  and the robot  300  can move independently, and the robot  300 , the unloader  500 , the elevator  600 , and the conveyor  400  cooperate with each other, so that an operator can conveniently sort goods. Moreover, the difficulty in an implementation and deployment is reduced, the workload of deploying and handling the sorting system is reduced, and the cost is reduced. 
     The sorting system provided by the foregoing embodiments has the following advantages: 
     1. The conveyor  400  is provided between the robot  300  and the operator, thereby improving the safety of the operator during work, since the operator does not directly perform an operation on the robot  300 . The first storage layer  411  at the lower part of the conveyor  400  can actively extend out of the second supporting frame  410 , so that the operator does not need to climb up when sorting goods, thereby improving the friendliness in operation. 
     2. The first storage layer  411  at the lower part of the conveyor  400  can extend out of the second supporting frame  410 , making it convenient for the operator to sort goods in the logistics crate  200 . Friendly human-computer interaction is achieved, and the operator can stand to work at a comfortable height that can be reached. 
     3. By providing the unloader  500  and the conveyor  400 , the robot  300  can transport the logistics crate  200  thereon to the unloader  500  or the conveyor  400  at a same time, thereby improving the work efficiency of the robot  300 . The robot  300  can unload the logistics crate  200  to the unloader  500  or the conveyor  400  or transport the logistics crate  200  on the unloader  500  or the conveyor  400  to the robot  300  at a same time. The robot  300  will not be occupied for a long time due to slow manual operation, thereby increasing the actual effective working time of the robot  300  and improving the efficiency. 
     4. By providing the movable elevator  600 , one elevator  600  can correspond to multiple unloaders  500  or conveyors  400 , and complete transportation of goods through cyclic lifting/lowering, making full use of the performance of the elevator  600  and reducing the overall cost. 
     5. The sorting system may include the robot  300 , the unloader  500 , the elevator  600 , and the conveyor  400  which are independently designed, and the four different sorting systems in an embodiment 3 to an embodiment 6 can be selected according to the size of the warehouse and needs for the efficiency of warehouse logistics. The sorting system is made flexible and modular, and each part can be moved and assembled independently, reducing the difficulty in an implementation and deployment, the workload of migration, and the cost. The sorting system is suitable for leased warehouses, or warehouses that require dynamic changes to operation processes. 
     Embodiment 7 
       FIG.  23    is a first flowchart of a sorting method according to an embodiment of this application. With reference to  FIG.  23   , this application further provides a sorting method, using the sorting system provided in an embodiment 3 above. The sorting method includes the following steps: 
     S 101 : Receive, by the robot, a logistics crate to be sorted. 
     Specifically, the logistics crates  200  are placed one by one into the multiple transfer devices  100  provided on the robot  300  through the fork  313  on the robot  300 . At least one logistics crate  200  can be placed in each of the transfer devices  100 , and at least one piece of goods is placed in each of the logistics crates  200 . The logistics crates  200  placed on each of the transfer devices  100  of the robot  300  may be the same or different. 
     S 102 : Receive, by the conveyor, the logistics crate on the robot so as to sort the logistics crate on the conveyor. 
     Specifically, the first storage layer  411  on the conveyor  400  may be provided in one-to-one correspondence to the transfer device  100  on the robot  300 . The first storage layer  411  receives the logistics crate  200  on the robot  300 . The operator pulls out the first storage layer  411  at the lower part of the conveyor  400 , or the first storage layer  411  automatically extends out of the lower part of the conveyor  400 , or the transfer mechanism  417  rotates to the lower part of the conveyor  400 , and the operator sorts goods in the logistics crate  200  on the first storage layer  411  or the transfer mechanism  417  to deliver the goods to the rack  700  or the goods transport assembly. In this way, direct contact between the operator and the robot  300  is avoided, the unloading speed of the robot  300  is increased, the unloading time of the robot  300  is reduced, and the work efficiency of the robot  300  is improved. 
     Optionally, after S 102 , the sorting method provided in this application further includes: transporting, by the conveyor  400 , the logistics crate  200  to the robot  300 . That is, the conveyor  400  can transport a new logistics crate  200  or a sorted logistics crate  200  thereon to the robot  300 , so that the robot  300  transports the new logistics crate  200  or the sorted logistics crate  200  to a warehouse. 
     Embodiment 8 
       FIG.  24    is a second flowchart of a sorting method according to an embodiment of this application. With reference to  FIG.  24   , this application further provides a sorting method, using the sorting system provided in an embodiment 4 above. The sorting method includes the following steps: 
     S 201 : Receive, by the robot, a logistics crate to be sorted. 
     S 202 : Receive, by the unloader, the logistics crate on the robot, and transport the logistics crate to the conveyor. 
     Specifically, the second storage layer  520  on the unloader  500  is in one-to-one correspondence to the transfer device  100  on the robot  300 , the transfer device  100  on the robot  300  is used for placing the logistics crate  200 , and the second storage layer  520  on the unloader  500  receive the logistics crate  200  in the robot  300  and transports the logistics crate  200  to the transfer mechanisms  417  on the conveyor  400 . 
     S 203 : Receive, by the conveyor, the logistics crate on the unloader so as to sort the logistics crate on the conveyor. 
     Specifically, the transfer mechanisms  417  on the conveyor  400  receive the logistics crate  200  on the unloader  500 , and the operator sorts goods in the logistics crate  200  on the transfer mechanisms  417  to deliver the goods to the rack  700  or the goods transport assembly. 
     Optionally, after S 203 , the sorting method provided in this application further includes: transporting, by the conveyor  400 , the logistics crate  200  to the robot  300  through the unloader  500 . That is, the conveyor  400  can transport a new logistics crate  200  or a sorted logistics crate  200  thereon to the unloader  500 , and the unloader  500  transports the new logistics crate  200  or the sorted logistics crate  200  to the robot  300 , so that the robot  300  transports the new logistics crate  200  or the sorted logistics crate  200  to a warehouse. 
     Embodiment 9 
       FIG.  25    is a third flowchart of a sorting method according to an embodiment of this application. With reference to  FIG.  25   , this application further provides a sorting method, using the sorting system provided in an embodiment 5 above. The sorting method includes the following steps: 
     S 301 : Receive, by the robot, a logistics crate to be sorted. 
     S 302 : Receive, by the elevator, the logistics crate on the robot, and transport the logistics crate to the conveyor. 
     Specifically, the elevator  600  moves to the robot  300 , and the third storage layer  620  on the elevator  600  receives the logistics crate  200  placed on the transfer device  100  on the robot  300  and transport the logistics crate  200  to the first storage layer  411  on the conveyor  400 . 
     S 303 : Receive, by the conveyor, the logistics crate on the elevator so as to sort the logistics crate on the conveyor. 
     Specifically, the first storage layer  411  on the conveyor  400  receives the logistics crate  200  placed on the third storage layers  620  on the elevator  600 , and the operator sorts goods in the logistics crate  200  on the first storage layer  411  to deliver the goods to the rack  700  or the goods transport assembly. 
     After the logistics crate  200  is sorted, the sorted logistics crate  200  on the first storage layer  411  at the lower part of the conveyor  400  can be transported to the robot  300 , or transported to the first storage layer  411  at the upper part of the conveyor  400  for temporary storage. By the cyclic lifting and lowering of the third storage layer  620  of the elevator  600 , the logistics crate  200  that is not sorted at the upper part of the conveyor  400  can also be transported to the first storage layer  411  at the lower part of the conveyor  400  for sorting. Optionally, after S 303 , the sorting method provided in this application further includes: transporting, by the conveyor  400 , the logistics crate  200  to the robot  300  through the elevator  600 . That is, the conveyor  400  can transport a new logistics crate  200  or a sorted logistics crate  200  thereon to the elevator  600 , and the elevator  600  transports the new logistics crate  200  or the sorted logistics crate  200  to the robot  300 , so that the robot  300  transports the new logistics crate  200  or the sorted logistics crate  200  to a warehouse. 
     Embodiment 10 
       FIG.  26    is a fourth flowchart of a sorting method according to an embodiment of this application. With reference to  FIG.  26   , this application further provides a sorting method, using the sorting system provided in an embodiment 5 above. The sorting method includes the following steps: 
     S 401 : Receive, by the robot, a logistics crate to be sorted. 
     Specifically, the robot  300  receives an instruction for picking up at least one logistics crate  200  to be sorted, and puts the logistics crate  200  one by one into the transfer devices  100  provided on the robot  300  through the fork  313  on the robot  300 . An identifier used for identifying the goods in the logistics crate  200 , such as a QR code, can be attached to the logistics crate  200 . 
     S 402 : Receive, by the unloader, the logistics crate on the robot, and transport the logistics crate to the elevator. 
     Specifically, the second storage layer  520  on the unloader  500  is in one-to-one correspondence to the transfer device  100  on the robot  300 , the transfer device  100  on the robot  300  is used for placing the logistics crate  200 , and the second storage layer  520  on the unloader  500  receives the logistics crate  200  in the robot  300  and transports the logistics crate  200  to the elevator  600 . 
     S 403 : Receive, by the elevator, the logistics crate on the unloader, and transport the logistics crate to the conveyor. 
     Specifically, the third storage layer  620  in the elevator  600  receives the logistics crate  200  on the second storage layer  520  on the unloader  500 . The elevator  600  moves to the position of the conveyor  400  and transports the logistics crate  200  to the transfer mechanisms  417  or the first storage layers  411  on the conveyor  400 . 
     S 404 : Receive, by the conveyor, the logistics crate on the unloader so as to sort the logistics crate on the conveyor. 
     Specifically, the transfer mechanism  417  or the first storage layer  411  on the conveyor  400  receives the logistics crate  200  placed on the third storage layer  620  on the elevator  600 , and the operator sorts goods in the logistics crate  200  on the first storage layer  411  or the transfer mechanism  417  to deliver the goods to the rack  700  or the goods transport assembly. Exemplarily, in order to make it convenient for the operator to put sorted goods into a corresponding box  710 , an indicator light is provided below the box  710 , and the indicator light is used for giving a prompt about a placement position to the operator. The pattern and text of the indicator light can be matched with the goods. After sorting the goods, the operator can also place the goods on the goods transport assembly, such as a conveyor line and other transport assemblies. The operator places the logistics crate  200  on the conveyor line, and other equipment or operators classify same, thereby further improving the sorting efficiency. 
     If at least two pieces of goods are placed in the logistics crate  200 , the same operator may place the goods in corresponding different boxes  710  in the rack  700 , or different operators place the goods in corresponding different boxes  710  in the rack  700 . 
     Each box  710  may correspond to a different order, and each box  710  may contain at least one piece of goods. Through the above-mentioned sorting method, the goods can be placed in the boxes  710  corresponding to the same orders. 
     After the logistics crate  200  is sorted, the sorted logistics crate  200  on the first storage layer  411  at the lower part of the conveyor  400  can be transported to the unloader  500 , or transported to the first storage layer  411  at the upper part of the conveyor  400  for temporary storage. By the cyclic lifting and lowering of the third storage layer  620  of the elevator  600 , the logistics crate  200  that is not sorted at the upper part of the conveyor  400  can also be transported to the first storage layer  411  at the lower part of the conveyor  400  for sorting. 
     Optionally, after S 403 , the sorting method provided in this application further includes: transporting, by the conveyor, the logistics crate to the robot sequentially through the elevator and the unloader. That is, the conveyor  400  can transport a new logistics crate  200  or a sorted logistics crate  200  thereon to the elevator  600 , the elevator  600  transports the new logistics crate  200  or the sorted logistics crate  200  to the unloader  500 , and the unloader  500  transports the new logistics crate  200  or the sorted logistics crate  200  to the robot  300 , so that the robot  300  transports the new logistics crate  200  or the sorted logistics crate  200  to a warehouse. 
     Finally, the foregoing embodiments are merely used for describing the technical solutions of this application, rather than limiting this application. Although this application is described in detail with reference to the foregoing embodiments, a person of ordinary skill in the art is to understand that they can still make modifications to the technical solutions described in the foregoing embodiments or make equivalent replacements on some or all of technical features therein. These modifications or replacements do not cause the essence of the corresponding technical solutions to depart from the scope of the technical solutions of the embodiments of this application.