Intelligent material storing and taking system and goods detection method

Abstract

According to the intelligent material storing and taking system, upper and lower adjacent storage units of a goods shelf communicate with each other, a pallet fork is installed on a trolley, and the pallet fork can slide left and right along the trolley and can push a material box into the storage units; one side of the bottom of the goods shelf is further provided with a material storing and taking opening, a female support is arranged in the material storing and taking opening, a plurality of material boxes can be placed on the female support, the trolley is located between the material storing and taking opening and the goods shelf and can move up and down, and when the trolley descends to the material storing and taking opening, the female support can horizontally move to the trolley from the interior of the material storing and taking opening. The PLC controls the movement of the trolley, the pallet fork and the female support; the transmitting end and the receiving end of the height measuring grating are arranged on the two sides of the trolley respectively; the height measuring grating is connected with the register, and the register is connected with the PLC. The invention further discloses a goods detection method of the system. For the goods with different heights, the system has high applicability, can accurately identify and detect the warehousing goods, and dynamically distributes the storage space for the warehousing goods in time, so that the space utilization rate and the warehousing efficiency are improved, and the stability and the reliability of the system are ensured.

Description

Technical Field

[0001] The present invention belongs to the field of warehousing, and in particular relates to an intelligent material storage and retrieval system and a goods detection method. Background Art

[0002] In existing automated warehousing systems, one product usually corresponds to one storage unit. This can improve the storage and retrieval efficiency of shelves for large quantities of the same products, but it also limits the scope of application of the warehousing system.

[0003] For goods of different sizes or heights, intelligent storage systems often require intelligent identification of the goods' sizes and allocation of appropriate storage space. However, existing systems often suffer from inaccurate goods size identification, complex allocation logic, and low efficiency. Summary of the Invention

[0004] In response to the above content, the present invention provides an intelligent storage and retrieval system and a goods detection method, which has strong applicability for goods of different heights, can accurately identify and detect incoming goods, and dynamically allocate storage space for them in a timely manner, thereby improving space utilization and warehousing efficiency, and ensuring the stability and reliability of the system.

[0005] Disclosed is an intelligent material storage and retrieval system, which includes a shelf, a material box, a trolley, a fork, a material storage and retrieval port, a mother tray, a PLC, a height measuring grating and a register;

[0006] The shelf is divided into a plurality of storage units in the longitudinal and transverse directions, and the upper and lower adjacent storage units are connected, so that if the height of the goods in the material box exceeds the height of one storage unit, it can also be stored in the shelf by occupying two or more storage units above and below;

[0007] The trolley is arranged next to the shelf, and the trolley can move up and down under the drive of the first servo motor. The moving structure of the trolley and the connection method between the trolley and the first servo motor refer to the flexible guide structure and transmission structure in our patent publication number CN119551333A, which will not be repeated here. The trolley of this application is the same as the up and down walking pulley in the patent;

[0008] The fork is mounted on the trolley and can slide left and right along the trolley through the second servo motor. When the material box is placed on the fork, the fork can push the material box into the storage unit of the shelf under the drive of the third servo motor, and vice versa, it can take the material box out of the storage unit; the driving assembly of the fork includes a transmission gear, a reducer, a servo motor, a conveyor belt, a roller and a guide rail, etc., which is a prior art and will not be described in detail here;

[0009] The bottom side of the shelf is also provided with a storage and access port, and a mother tray is provided in the storage and access port. The mother tray is a hollow frame structure, and multiple material boxes can be placed on the mother tray. The trolley is located between the storage and access port and the shelf. When the trolley descends to the storage and access port, the mother tray can be translated from the storage and access port to the trolley under the drive of the fourth servo motor, so that multiple material boxes can be loaded simultaneously through the mother tray. The mother tray moves as the trolley rises and moves, and the material boxes on the mother tray are respectively sent to the corresponding storage units of the shelf by the fork; the material taking process is the opposite of the above process. First, the fork takes out multiple material boxes from the corresponding storage units of the shelf and places them on the mother tray. Then the mother tray descends to the storage and access port with the trolley, and the mother tray is pushed out to the storage and access port as a whole to realize simultaneous unloading of multiple material boxes.

[0010] The structure of the access port is the same as that of the inlet and outlet ports in our patent publication number CN119551333A. The structure of the mother tray is the same as the tray in the patent, and the cooperation method between them is also disclosed in the patent, that is, the mother tray is translated from the access port to the trolley and from the trolley to the access port through the tray discharge structure in the patent.

[0011] The PLC controls the movement of the trolley, fork and carrier through servo drives respectively;

[0012] The height measuring grating is installed behind the material access port, and the transmitting end and receiving end of the height measuring grating are respectively arranged on both sides of the trolley. The transmitting end of the height measuring grating can emit several parallel light beams with equal spacing to form a detection light curtain;

[0013] When the trolley descends to the access port, the frame plate of the trolley near the access port can be partially in the detection light curtain of the height measuring grating. By adjusting the shape and size of the frame plate in advance, the highest point of the trolley frame plate that can be detected by the detection light curtain and the bottom surface of the mother tray loading box are at the same level, that is, the reference Figure 2 Point a in the figure is the highest point of the trolley frame that can be detected by the height measuring grating. It is located at the same level as the bottom surface of the mother tray loading box and has the same height. So when the trolley descends to the access port, the bottom surface value of the mother tray loading box can be indirectly determined by detecting the trolley frame. Of course, at this time Figure 2 The middle mother tray has been moved horizontally to the trolley. When storing materials, the mother tray is inside the material storage and retrieval port, which will not affect the detection of point a on the trolley frame plate;

[0014] When the mother tray is moved horizontally from the access port to the trolley, the goods in the mother tray loading box can also pass through the detection light curtain of the height measuring grating;

[0015] The altimeter is connected to a register, which is connected to a PLC. When an object passes through the detection light curtain of the altimeter, part of the light beam is blocked. The receiving end of the altimeter collects the light beam status signal and locks it in the register. The PLC reads the data locked in the register as needed.

[0016] Furthermore, the first servo motor of the trolley and the second servo motor of the fork are respectively equipped with incremental encoders, and the incremental encoders are connected to the high-speed counter module of the PLC, which can feed back the position signals of the trolley and the fork to the PLC; each time materials are stored in or out of the shelf, the trolley will rise to the layer where the target storage unit is located, and the fork will move to the column where the target storage unit is located, so that the position coordinates fed back by the trolley and the fork when storing or retrieving materials are used to record and update the occupancy status of the corresponding storage unit on the shelf, and these occupancy states are all memorized in the data block of the PLC to form shelf parameters.

[0017] Preferably, the intelligent storage and retrieval system further includes a host computer, which is connected to the PLC. An operator can set parameters and issue commands to the PLC controller through the host computer.

[0018] Also disclosed is a product detection method for the intelligent storage and retrieval system, which includes the following steps:

[0019] S1. The operator issues a material storage command to the PLC through the host computer. After the PLC controls the trolley to descend to the inlet and outlet, the PLC issues a reset command to the register to avoid interference with previously latched data. After the reset is completed, the receiving end of the height measuring grating locks the currently detected beam status signal of the trolley frame into the register and defines it as the reference signal;

[0020] S2. After the operator places the material box containing the goods on the mother tray, he or she again issues a confirmation order to the PLC through the host computer. The PLC controls the mother tray to move horizontally from the access port to the trolley. The goods in the material box on the mother tray pass through the detection light curtain of the height measuring grating. The receiving end of the height measuring grating locks the detected light beam status signal into the register and defines it as the final signal.

[0021] S3. The PLC reads the reference signal and final signal latched in the register. In the PLC's signal processing module, the acquired beam status signals are mapped into an ascending natural number index sequence from bottom to top according to the physical positions of all beams (i.e., the index value of each beam is a natural number such as 1, 2, 3, ..., N). The index values ​​of all beams with a "blocked" status are extracted. The maximum beam index value in the reference signal is defined as the reference value, and the maximum beam index value in the final signal is defined as the final value.

[0022] S4. In the PLC calculation module, the following formula is used: Number of layers occupied by bins and items = (final value - baseline value) × spacing between adjacent beams / storage unit height. The calculation outputs the number of layers occupied.

[0023] The spacing between adjacent beams of the height measuring grating and the height of the storage unit of the shelf can be input when setting the parameters of the host computer. In the actual storage and retrieval system, the spacing between adjacent beams of the height measuring grating is 10mm, and the height of the storage unit of the shelf is 250mm.

[0024] S5. In the PLC comparison and allocation module, the occupied layer number value obtained in S4 is loaded and the current shelf parameters stored in the PLC data block are read. The shelf parameters represent the occupancy status of the shelf storage units, which are divided into two states: "free" and "occupied." The storage units in the shelf parameters with a status of "free" are traversed in order from bottom to top and from left to right, based on their physical location:

[0025] If the number of "free" storage units found in the upper and lower continuous states is greater than or equal to the number of occupied layers, the multiple "free" storage units that meet this condition are defined as the target storage space of the shelf, and the PLC console and fork are used to store the boxes and goods on the mother pallet into the target storage space of the shelf;

[0026] If the number of "free" storage units in all the upper and lower continuous states traversed is less than the number of occupied layers, the PLC controls the mother tray to return the material box and goods to the storage and retrieval port, and an alarm is triggered.

[0027] Through the above technical solution, the present invention has at least the following beneficial effects:

[0028] The intelligent storage and retrieval system described in the present application has open dynamic space allocation shelves, and goods can be stored simultaneously in multiple storage units that are continuous above and below. This reduces the restrictions on the height of the goods, and goods of different heights can also be stored in the shelves, expanding the scope of application of the intelligent storage and retrieval system.

[0029] The intelligent identification of the height of goods and the dynamic allocation of storage space for them are achieved through the goods detection method described in this application. It can accurately identify and detect incoming goods when storing materials, and timely determine the number of continuous storage units required for the goods to occupy, and dynamically allocate storage space on the shelves for them, thereby improving space utilization and warehousing efficiency, allowing goods to avoid occupied storage units, and preventing goods from being too high and colliding with and affecting the material boxes in the storage units on the upper layer, so as to ensure stable operation of the system.

[0030] In addition, in the above method, the coordinated design of the height measuring grating, register and PLC modules can effectively improve the accuracy of product detection and identification, ensuring the reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. These drawings are all simplified schematic diagrams that only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0032] Figure 1 This is a structural diagram of the intelligent storage and retrieval system described in an embodiment of the present application (the shelves in the figure can be expanded upward infinitely, and only part of them is shown here);

[0033] Figure 2 This is a partial schematic diagram of the frame plate of the trolley located in the detection light curtain in the embodiment of the present application. DETAILED DESCRIPTION

[0034] In the description of this application, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the terms describing the positional relationship are only used for illustrative purposes and cannot be understood as limiting this patent; if there are terms such as "first", "second", etc., they are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the said features. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0035] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "provided with," "connected," etc., should be understood in a broad sense. For example, "connected" can mean a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this invention based on specific circumstances.

[0036] refer to Figure 1 An intelligent material storage and retrieval system includes a shelf 1, a material box 2, a trolley 3, a fork 4, a material storage and retrieval port 5, a mother tray 6, a PLC, a height measuring grating and a register;

[0037] The shelf 1 is divided into a plurality of storage units in the longitudinal and transverse directions, and the upper and lower adjacent storage units are connected. In this way, if the height of the goods in the material box 2 exceeds the height of one storage unit, it can also be stored in the shelf 1 by occupying two or more storage units above and below;

[0038] The trolley 3 is arranged next to the shelf 1. The trolley 3 can move up and down under the drive of the first servo motor. The moving structure of the trolley 3 and the connection method of the trolley 3 and the first servo motor refer to the flexible guide structure and transmission structure in our patent publication number CN119551333A. No further details are given here. The trolley 3 of this application is the same as the up and down walking pulley in the patent;

[0039] The fork 4 is mounted on the trolley 3 and can slide left and right along the trolley 3 through the second servo motor. When the material box 2 is placed on the fork 4, the fork 4 can push the material box 2 into the storage unit of the shelf 1 under the drive of the third servo motor, and vice versa, it can take the material box 2 out of the storage unit; the driving assembly of the fork 4 includes a transmission gear, a reducer, a servo motor, a conveyor belt, a roller and a guide rail, etc., which are existing technologies and will not be described in detail here;

[0040] When the trolley 3 is lowered to the access port 5, the mother tray 6 can be moved horizontally from the access port 5 to the trolley 3, so that the simultaneous loading of multiple bins 2 can be achieved through the mother tray 6. The mother tray 6 moves as the trolley 3 rises, and the forks 4 are used to deliver the bins 2 on the mother tray 6 to the corresponding storage units of the shelf 1. The material taking process is the opposite of the above process. First, the fork 4 takes out multiple bins 2 from the corresponding storage units of the shelf 1 and places them on the mother tray 6. Then, the mother tray 6 descends with the trolley 3 to the access port 5, and the mother tray 6 is pushed out to the access port 5 as a whole to achieve simultaneous unloading of multiple bins 2.

[0041] The structure of the access port 5 is the same as that of the inlet and outlet ports in our patent publication number CN119551333A. The structure of the mother tray 6 is the same as the tray in the patent, and the cooperation method between them is also disclosed in the patent, that is, the mother tray 6 is translated from the access port 5 to the trolley 3 and from the trolley 3 to the access port 5 through the tray discharge structure in the patent.

[0042] The PLC controls the movement of the trolley 3, the fork 4 and the carrier 6 through the servo drive respectively;

[0043] The altimeter grating is installed behind the access port 5. The transmitting end 701 and the receiving end 702 of the altimeter grating are respectively arranged on both sides of the trolley 3. The transmitting end 701 of the altimeter grating can emit several parallel light beams with equal spacing to form a detection light curtain 703.

[0044] When the trolley 3 descends to the access port 5, the frame plate 301 of the trolley 3 near the access port 5 can be partially in the detection light curtain 703 of the height measuring grating. By adjusting the shape and size of the frame plate 301 in advance, the highest point of the trolley 3 frame plate 301 that can be detected by the detection light curtain 703 is at the same level as the bottom surface of the loading box 2 placed on the mother tray 6, that is, reference Figure 2 , point a in the figure is the highest point of the frame plate 301 of the trolley 3 that can be detected by the height measuring grating. It is located at the same horizontal plane as the bottom surface of the mother tray 6 loading box 2 and has the same height. In this way, when the trolley 3 descends to the access port 5, the bottom surface value of the mother tray 6 loading box 2 can be indirectly determined by detecting the frame plate 301 of the trolley 3. Of course, at this time Figure 2 The middle mother tray 6 has been translated onto the trolley 3. When storing materials, the mother tray 6 is inside the material storage and retrieval port 5 and will not affect the detection of point a of the frame plate 301 of the trolley 3.

[0045] When the mother tray 6 is translated from the access port 5 to the trolley 3, the goods in the material box 2 of the mother tray 6 can also pass through the detection light curtain 703 of the height measuring grating;

[0046] The altimeter is connected to a register, which is connected to a PLC. When an object passes through the detection light curtain 703 of the altimeter, part of the light beam is blocked. The receiving end 702 of the altimeter collects the light beam status signal and locks it in the register. The PLC reads the data locked in the register as needed.

[0047] The first servo motor of the trolley 3 and the second servo motor of the fork 4 are respectively equipped with incremental encoders, which are connected to the high-speed counter module of the PLC and can feed back the position signals of the trolley 3 and the fork 4 to the PLC; each time materials are stored or retrieved from the shelf 1, the trolley 3 will rise to the layer where the target storage unit is located, and the fork 4 will move to the column where the target storage unit is located. In this way, the position coordinates fed back by the trolley 3 and the fork 4 when storing or retrieving materials are used to record and change the occupied status of the corresponding storage unit of the shelf 1, and these occupied statuses are all memorized in the data block of the PLC to form the shelf 1 parameters.

[0048] The intelligent storage and retrieval system also includes a host computer, which is connected to the PLC. An operator can set parameters and issue commands to the PLC controller through the host computer.

[0049] The above-mentioned intelligent storage and retrieval system has an open dynamic space allocation shelf 1, and goods can be stored in multiple storage units connected vertically at the same time. This reduces the restrictions on the height of the goods, and goods of different heights can also be stored in the shelf 1, expanding the scope of application of the intelligent storage and retrieval system.

[0050] When storing materials through the above system, the goods can be detected and storage space can be dynamically allocated for them. The goods detection method includes the following processes:

[0051] S1. The operator issues a stocking command to the PLC through the host computer. After the PLC controls the trolley 3 and descends to the inlet and outlet, the PLC issues a clear command to the register to avoid interference with the previously latched data. After the clearing is completed, the receiving end 702 of the height measuring grating locks the beam status signal of the currently detected trolley 3 frame plate 301 in the register and defines it as a reference signal.

[0052] S2. After the operator places the material box 2 containing the goods on the mother tray 6, the host computer again issues a confirmation command to the PLC. The PLC controls the mother tray 6 to move horizontally from the access port 5 to the trolley 3. The goods in the material box 2 on the mother tray 6 pass through the detection light curtain 703 of the height measuring grating. The receiving end 702 of the height measuring grating locks the detected light beam status signal in the register and defines it as the final signal.

[0053] S3. The PLC reads the reference signal and final signal latched in the register. In the PLC's signal processing module, the acquired beam status signals are mapped into an ascending natural number index sequence from bottom to top according to the physical positions of all beams (i.e., the index value of each beam is a natural number such as 1, 2, 3, ..., N). The index values ​​of all beams with a "blocked" status are extracted. The maximum beam index value in the reference signal is defined as the reference value, and the maximum beam index value in the final signal is defined as the final value.

[0054] S4. In the PLC calculation module, the following formula is used: Number of layers occupied by bin 2 and the product = (final value - baseline value) × spacing between adjacent beams / storage unit height. The calculation outputs the number of layers occupied.

[0055] The spacing between adjacent beams of the height measuring grating and the height of the storage unit of shelf 1 can be input when setting the parameters of the host computer. In the actual storage and retrieval system, the spacing between adjacent beams of the height measuring grating is 10mm, and the height of the storage unit of shelf 1 is 250mm.

[0056] S5. In the PLC comparison and allocation module, the occupied layer number value obtained in S4 is loaded and the current shelf 1 parameter stored in the PLC data block is read. The shelf 1 parameter represents the occupancy status of the storage units in shelf 1, which is divided into two states: "free" and "occupied". The storage units in the shelf 1 parameter with a status of "free" are traversed in order from bottom to top and from left to right according to the physical location of the storage units:

[0057] If the number of "free" storage units found in the upper and lower continuous states is greater than or equal to the number of occupied layers, the multiple "free" storage units that meet this condition are defined as the target storage space of shelf 1, and the PLC control console trolley 3 and fork 4 are used to store the material box 2 and the goods on the mother pallet 6 into the target storage space of shelf 1;

[0058] If the number of all the traversed upper and lower continuous storage units that are in the "free" state is less than the value of the number of occupied layers, the PLC controls the mother tray 6 to return the material box 2 and the goods to the access port 5, and an alarm is prompted.

[0059] In this way, when materials are put into the warehouse, the incoming goods can be accurately identified and measured, the number of continuous storage units that the items need to occupy can be determined in a timely manner, and the storage space of shelf 1 can be dynamically allocated for them, thereby improving space utilization and storage efficiency. It can enable goods to avoid occupied storage units, avoid goods being too high and colliding with the material box 2 in the storage unit on the upper layer, and ensure stable operation of the system.

[0060] In existing technology, light barriers are often used to detect goods. For example, the transmitting end of a light barrier emits a beam every 10 mm, and the receiving end needs to send the received beam signal to the controller every 20 ms. However, this can lead to the system failing to recognize small objects passing quickly, resulting in misjudgment. For example, an object less than 20 mm in diameter passing through the light curtain at a speed of 1000 mm / s will pass within 20 ms. This means that the signal is likely to be lost due to inadequate transmission.

[0061] The system and product detection method described in this embodiment can solve the above problems well through the coordinated design of the altimeter, register and PLC modules. Any light beam signal collected by the altimeter can be locked in the register. The PLC reads the latched data on demand and avoids data interference through clearing instructions, which can effectively improve the accuracy of product detection and identification and ensure the reliability of the system.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Based on the present invention and the above description, relevant personnel can make various changes and modifications without departing from the technical idea of ​​the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An intelligent material storage and retrieval system, characterized by: It includes a shelf (1), a material box (2), a trolley (3), a fork (4), a material storage and retrieval port (5), a mother tray (6), a PLC, a height measuring grating and a register; The shelf (1) is divided into a plurality of storage units in the longitudinal and transverse directions, and the upper and lower adjacent storage units are connected; the trolley (3) is arranged beside the shelf (1), and the trolley (3) can move up and down under the drive of a first servo motor; the fork (4) is installed on the trolley (3), and the fork (4) can slide left and right along the trolley (3) through a second servo motor, and when the material box (2) is placed on the fork (4), the fork (4) can push the material box (2) into the storage unit of the shelf (1) under the drive of a third servo motor; A material access opening (5) is further provided on one side of the bottom of the shelf (1), and a mother support (6) is provided in the material access opening (5). The mother support (6) is a hollow frame structure, and a plurality of material boxes (2) can be placed on the mother support (6). The trolley (3) is located between the material access opening (5) and the shelf (1). When the trolley (3) descends to the material access opening (5), the mother support (6) can be translated from the material access opening (5) to the trolley (3) under the drive of the fourth servo motor; The PLC controls the movement of the trolley (3), the fork (4) and the mother support (6) respectively through the servo drive; The altimeter grating is installed behind the access port (5), and the transmitting end (701) and receiving end (702) of the altimeter grating are respectively arranged on both sides of the trolley (3). The transmitting end (701) of the altimeter grating can emit a plurality of parallel light beams with equal spacing to form a detection light curtain (703); When the trolley (3) descends to the access port (5), the frame plate (301) of the trolley (3) near the access port (5) can be partially located in the detection light curtain (703) of the height measuring grating, and the highest point of the frame plate (301) of the trolley (3) that can be detected by the detection light curtain (703) and the bottom surface of the loading box (2) placed on the mother tray (6) are located at the same horizontal plane; When the mother tray (6) is translated from the access port (5) to the trolley (3), the goods in the feeding box (2) of the mother tray (6) can also pass through the detection light curtain (703) of the height measuring grating; The height measuring grating is connected to a register, and the register is connected to a PLC.

2. The intelligent material storage and retrieval system according to claim 1, characterized in that: The first servo motor of the trolley (3) and the second servo motor of the fork (4) are respectively equipped with incremental encoders, and the incremental encoders are connected to the high-speed counter module of the PLC and can feed back the position signals of the trolley (3) and the fork (4) to the PLC.

3. The intelligent material storage and retrieval system according to claim 2, characterized in that: It also includes a host computer, which is connected to the PLC.

4. A method for detecting goods in an intelligent storage and retrieval system according to claim 3, characterized in that: The following processes are included: S1. The operator issues a stocking command to the PLC through the host computer. After the PLC controls the trolley (3) to descend to the inlet and outlet, the PLC issues a reset command to the register. After the reset is completed, the receiving end (702) of the height measuring grating locks the light beam status signal of the currently detected trolley (3) frame (301) in the register and defines it as a reference signal. S2. After the operator places the material box (2) containing the goods on the mother tray (6), he / she again issues a storage confirmation command to the PLC through the host computer. The PLC controls the mother tray (6) to move horizontally from the access port (5) to the trolley (3). The goods in the material box (2) on the mother tray (6) pass through the detection light curtain (703) of the height measuring grating. The receiving end (702) of the height measuring grating locks the detected light beam status signal in the register and defines it as the final signal. S3. The PLC reads the reference signal and final signal latched in the register. In the PLC's signal processing module, the acquired beam status signals are mapped into an ascending natural number index sequence from bottom to top based on the physical positions of all beams. The index values ​​of all beams with a "blocked" status are extracted. The maximum beam index value in the reference signal is defined as the reference value, and the maximum beam index value in the final signal is defined as the final value. S4. In the calculation module of the PLC, according to the formula: the number of layers occupied by the bin (2) and the goods = (final value - reference value) × adjacent beam spacing ÷ storage unit height, the calculation is performed and the value of the number of layers occupied is output; S5. In the comparison and allocation module of the PLC, the value of the number of occupied layers obtained in S4 is loaded, and the current shelf (1) parameter stored in the PLC data block is read. The shelf (1) parameter is the occupied state of the storage unit of shelf (1), which is divided into two states: "free" and "occupied". The storage units in the shelf (1) parameter with the state of "free" are traversed in sequence: If the number of "free" storage units that are traversed continuously from top to bottom is greater than or equal to the number of occupied layers, the multiple "free" storage units that meet this condition are defined as the target storage space of the shelf (1), and the PLC control console (3) and the fork (4) are used to store the material box (2) and the goods on the mother tray (6) into the target storage space of the shelf (1); If the number of all the traversed upper and lower continuous storage units that are in the "free" state is less than the value of the number of occupied layers, the PLC controls the mother tray (6) to return the material box (2) and the goods to the storage and retrieval port (5).

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