Sorting control system and method for express sorting machine

Abstract

The invention discloses a sorting control system and method for an express sorting machine. The sorting control system comprises a sorting machine body, a converging device installed on the inlet side of the sorting machine body, a sorting signal collecting device, a sorting executing device and a flow dividing and guiding device, wherein the sorting signal collecting device, the sorting executing device and the flow dividing and guiding device are sequentially arranged in the conveying direction of the sorting machine body. Through cooperative control of the multispectral camera, the RFID reader-writer, the dynamic confluence device and the intelligent mechanical arm, an improved AI algorithm and LSTM neural network prediction are combined, automatic optimization of the whole process from confluence, sorting to distribution of packages is achieved, the sorting efficiency is further improved, and the error rate is further reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of express logistics automation, and in particular to a sorting control system and method for an express sorting machine. Background Art

[0002] Express sorting machines are devices used to automatically sort express parcels. They play a vital role in express delivery companies and logistics centers, significantly improving logistics efficiency and service quality. With the continuous advancement of technology and the expansion of application scenarios, express sorting machines will play an even more important role in the future.

[0003] Express sorting machines leverage advanced mechanical technology and sensor systems, along with automated identification and positioning technologies, to quickly and accurately identify different items and sort and categorize them according to pre-set rules. Their core operating principle lies in the precise identification and classification of items being sorted. Assisted by conveyor belts, items are precisely scanned by automatic identification equipment and then sorted into their corresponding containers, enabling efficient and accurate sorting. Existing express sorting systems often employ the following technical solutions, but they still have significant drawbacks: Traditional sorting machines rely on fixed conveyor speeds and static routing, unable to dynamically adjust merging speeds or sorting priorities based on parcel flow, resulting in reduced sorting efficiency during peak periods; single sensors (such as barcode scanners) are susceptible to interference from package surface contamination and lighting changes, leading to information recognition errors; and the lack of coordinated control between the sorting actuator (such as the robotic arm) and the diversion guide device results in time delays between sorting actions and guide switching, which can easily cause parcel collisions or missed packages. Summary of the Invention

[0004] (1) Technical problems solved

[0005] In response to the shortcomings of the existing technology, the present invention adopts an express sorting machine sorting control system and method with multi-device collaborative control and dynamic path planning, which is particularly suitable for intelligent sorting scenarios in large-scale express distribution centers.

[0006] (2) Technical solution

[0007] To achieve the above objectives, the present invention provides the following technical solution: a sorting control system for an express sorting machine, comprising a sorting machine body, a merging device installed at the entrance side of the sorting machine body, a sorting signal acquisition device, a sorting execution device, and a diversion guide device sequentially arranged along the conveying direction of the sorting machine body, the sorting machine body comprising a plurality of parallel conveyor belts, each of which is provided with a speed sensor and a position encoder, and the conveyor belts are driven by a variable frequency motor; As a preferred solution, in the control system: The merging device is installed at the entrance side of the sorting machine body and includes a photoelectric sensor array and an adjustable baffle. The photoelectric sensor array detects the distance between packages and feeds back a signal to the central controller. The adjustable baffle is controlled by a first servo motor to open and close the angle to adjust the flow rate of packages entering the sorting machine body. The sorting signal acquisition device is installed above the sorting machine body, 2-3 meters from the entrance. It includes a multispectral camera and an RFID reader / writer. The multispectral camera is used to identify the size, shape and surface barcode of the package. The RFID reader / writer communicates with the electronic tag on the package to obtain the destination information. A sorting execution device is located 1.5-2 meters downstream of the sorting signal acquisition device, and includes a six-degree-of-freedom robotic arm and a gripper unit. The six-degree-of-freedom robotic arm is connected to the second servo motor via a harmonic reducer. The gripper unit has a built-in pressure sensor and is covered with a flexible material. The diversion guide device is installed at the end of the sorting machine body and includes a rotatable guide plate and a pneumatic push rod. The rotatable guide plate is driven by a stepper motor to rotate, and the thrust of the pneumatic push rod is dynamically adjusted according to the weight of the package; The central controller is electrically connected to the sorting machine body, merging device, sorting signal acquisition device, sorting execution device and diversion guide device. It has a built-in path planning algorithm and dynamic adjustment program to coordinate the actions of each device and generate sorting instructions.

[0008] As a preferred solution, the photoelectric sensor array of the merging device consists of two rows of staggered infrared sensors with a horizontal spacing of 10 cm and a vertical spacing of 20 cm, which are used to detect the three-dimensional position of the package; The servo motor of the adjustable baffle uses an absolute encoder to feedback the position, the opening and closing angle range of the baffle is 0°-90°, and the response time is ≤50ms.

[0009] As a preferred solution, the multispectral camera is installed at a height of 1.2-1.5 meters, with an inclination angle of 30°-45°, and its lens faces the direction of the package entering the conveyor belt; The RFID reader / writer operates at a frequency of 860-960 MHz, has a reading and writing distance of 0.5-1 meter, and synchronizes data with the multispectral camera via a timestamp.

[0010] As a preferred solution, the maximum load of the servo motor of the robotic arm is 15kg, and the repeatability accuracy is ±0.05mm; The pressure sensor of the gripper unit has a measuring range of 0-100N, and the detection signal is transmitted to the central controller via the CAN bus.

[0011] As a preferred solution, the surface of the guide plate of the diversion guide device is covered with a polyurethane buffer layer, and the rotation angle is calculated by the central controller according to the target diversion channel position, with an angle error of ≤1°; the maximum thrust of the pneumatic push rod is 200N, and the thrust value is proportional to the package weight, and is adjusted in real time through the PID algorithm.

[0012] As a preferred solution, the central controller adopts an industrial-grade PLC and industrial control collaborative architecture, and its path planning algorithm is an improved AI algorithm, which combines the kinematic constraints of the robotic arm and the sorting priority to dynamically generate an obstacle avoidance path.

[0013] A sorting control method for an express sorting machine comprises the following steps: S1, during the merging phase, the distance between packages at the entrance is detected by a photoelectric sensor array. If the distance is less than the set threshold (20-30 cm), the upstream conveyor speed is reduced or the baffle opening and closing angle is adjusted; S2: Sorting signal input, multispectral camera identifies the package barcode and size, RFID reader obtains destination information, and generates a unique sorting identifier after data fusion; S3, path planning: the central controller calculates the optimal sorting path and issues motion instructions based on the sorting mark, the current position of the robot arm, and the status of the distribution channel; S4: Sorting is executed. The robotic arm grabs the package according to the planned path. The pressure sensor provides real-time feedback on the gripping force. If slippage is detected, the gripper resets. S5, diversion and guidance: the guide plate rotates to the target angle, and the pneumatic push rod applies thrust according to the weight of the package to push the package to the designated diversion channel; S6. Exception handling: If a path conflict or equipment failure is detected during the sorting process, the central controller starts the dynamic adjustment program and reallocates the sorting tasks.

[0014] As a preferred solution, the optimal sorting path in S3 must meet the following requirements: the angular velocity of the robot arm joint does not exceed the rated value, and the sorting action time is ≤1.5 seconds.

[0015] As a preferred solution, the dynamic adjustment program in S6 trains the LSTM neural network through historical data to predict sorting congestion and adjust the path priority in advance.

[0016] (3) Beneficial effects Compared with the prior art, the present invention provides a sorting control system and method for an express sorting machine, which has the following beneficial effects: 1. The merging device of the present invention achieves dynamic balancing of parcel flow through a photoelectric sensor array and an adjustable baffle to avoid congestion at the entrance; its multispectral camera and RFID reader data are integrated to redundantly verify parcel information. The present invention achieves automated optimization of the entire process from merging, sorting to diversion of parcels through the coordinated control of multispectral cameras, RFID readers, dynamic merging devices, and intelligent robotic arms, combined with improved AI algorithms and LSTM neural network predictions, further improving sorting efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the control system structure of the present invention; Figure 2 Schematic diagram of the control method of the present invention.

[0018] In the figure: 1. Sorting machine body; 101. Conveyor belt; 102. Speed sensor; 103. Position encoder; 104. Frequency conversion motor; 2. merging device; 201. photoelectric sensor array; 202. adjustable baffle; 203. first servo motor; 3. Sorting signal acquisition device; 301. Multispectral camera; 302. RFID reader; 4. Sorting execution device; 401. Six-degree-of-freedom robotic arm; 402. Gripper unit; 403. Harmonic reducer; 404. Second servo motor; 405. Pressure sensor; 5. Diverter guide device; 501. Guide plate; 502. Pneumatic push rod; 503. Stepper motor; 6. Central controller. DETAILED DESCRIPTION

[0019] In order to better understand the purpose, structure and function of the present invention, the express sorting machine sorting control system and method of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0020] Example 1 refer to Figure 1 The present invention provides a sorting control system for an express sorting machine, comprising a sorting machine body 1, a merging device 2 installed at the entrance side of the sorting machine body 1, a sorting signal acquisition device 3, a sorting execution device 4 and a diversion guide device 5 arranged in sequence along the transmission direction of the sorting machine body 1.

[0021] Specifically, in this embodiment, the sorting machine body 1 includes multiple parallel conveyor belts 101, each of which is equipped with a speed sensor 102 and a position encoder 103. The conveyor belts 101 are driven by a variable frequency motor 104. The conveyor belts 101 are double-layered wear-resistant rubber belts with a width of 60 cm and anti-slip bumps at 10 cm intervals on the surface. The speed sensor 10 is a Hall effect sensor with a detection accuracy of ±0.01 m / s. The position encoder 103 is an incremental encoder (model: Omron E6B2-CWZ6C) with a resolution of 2000 pulses / rev.

[0022] Specifically, the merging device 2 is arranged at the entrance side of the sorting machine body 1 and includes a photoelectric sensor array 201 and an adjustable baffle 202. The photoelectric sensor array 201 detects the distance between packages and feeds back a signal to the central controller 6. The adjustable baffle 202 is controlled by a first servo motor 203 to adjust the flow of packages entering the sorting machine body 1 by opening and closing the angle. The photoelectric sensor array 201 consists of two rows of staggered infrared sensors (with a horizontal spacing of 10 cm and a vertical spacing of 20 cm). It detects the three-dimensional position of packages and calculates the distance between them. When the distance between adjacent packages is less than 25 cm, it triggers the central controller 6 to adjust the speed of the upstream conveyor belt or the opening and closing angle of the baffle. The adjustable baffle 202 is made of aluminum alloy with a nylon coating on the surface. The opening and closing angle is driven by a first servo motor 203 (model: Panasonic MINAS A6 series). The angle control accuracy is ±0.5°, the opening and closing speed of the baffle is positively correlated with the package flow rate, and the maximum response frequency is 50 Hz.

[0023] Specifically, the sorting signal acquisition device is installed above the sorting machine body 1, 2-3 meters from the entrance end, and includes a multispectral camera 301 and an RFID reader 302. The multispectral camera 301 is used to identify the size, shape and surface barcode of the package. The RFID reader 302 communicates with the electronic tag on the package to obtain destination information. The multispectral camera 301 is installed at a height of 1.3 meters, with an inclination angle of 40°, a field of view covering the width of the conveyor belt, and a resolution of 3840×2160 pixels. It has a built-in YOLOv7 algorithm to identify the package barcode and calculate the package size. The data of the RFID reader 302 and the multispectral camera 301 are aligned through timestamps. If the barcode and RFID information conflict, a manual review process is triggered.

[0024] Specifically, the sorting execution device 4 is located 1.5-2 meters downstream of the sorting signal acquisition device 3, and includes a six-degree-of-freedom robotic arm 401 and a gripper unit 402. The robotic arm 401 is connected to the second servo motor 404 through a harmonic reducer 403. The gripper unit 402 has a built-in pressure sensor 405 and is covered with a flexible material. The base of the six-degree-of-freedom robotic arm 401 is fixed on the side bracket of the conveyor belt, with a maximum arm span of 1.2 meters and a repeatability accuracy of ±0.03mm. The second servo motor 404 drives the joint through the harmonic reducer 403 and has a rated torque of 15Nm. The gripper unit 402 adopts a two-finger parallel gripper with a clamping force range of 5-50N. The flexible material is silicone. The pressure sensor 405 provides real-time feedback on the clamping force. If the force value fluctuation exceeds 20%, the gripper reset is triggered.

[0025] Specifically, the diversion guide device 5 is located at the end of the sorting machine body 1 and includes a rotatable guide plate 501 and a pneumatic push rod 502. The rotatable guide plate 501 is driven by a stepper motor 503 to adjust its rotation angle, and the thrust of the pneumatic push rod 502 is dynamically adjusted according to the weight of the package. The rotation axis of the rotatable guide plate 501d is driven by the stepper motor 503, and the rotation time to the designated position is ≤ 0.3 seconds. The thrust of the pneumatic push rod 502 ranges from 10 to 200N. The thrust is calculated based on the package weight fed back by the pressure sensor 405 according to the formula F = 0.2W + 5 (F is the thrust, W is the weight). The air system pressure is 0.6MPa, and the output is adjusted by a proportional valve.

[0026] The central controller 6 is electrically connected to the sorting machine body 1, the merging device 2, the sorting signal acquisition device 3, the sorting execution device 4, and the diversion guide device 5. It has a built-in path planning algorithm and dynamic adjustment program to coordinate the actions of each device and generate sorting instructions. Its PLC (Siemens S7-1500) is responsible for issuing real-time control instructions, and the industrial computer (Intel Xeon E5-2678) runs the path planning algorithm. The two machines synchronize data via the Profinet protocol, with a communication cycle of 1ms.

[0027] Furthermore, this embodiment introduces robot arm joint angular acceleration constraints by improving the AI algorithm to avoid over-limit movement. Its LSTM neural network inputs historical sorting data (such as the number of packages per hour and the type of sorting errors) and outputs a sorting strategy for the next 30 minutes.

[0028] Example 2 refer to Figure 1-2 The present invention provides a sorting control method for an express sorting machine, comprising the following steps: S1, merging stage, the distance between the inlet packages is detected by the photoelectric sensor array 201. If the distance is less than the set threshold (20-30cm), the upstream conveyor speed is reduced or the opening and closing angle of the baffle 20 is adjusted; S2: Sorting signal input, multispectral camera 301 identifies the package barcode and size, RFID reader 302 obtains the destination information, and generates a unique sorting identifier after data fusion; S3, path planning: the central controller calculates the optimal sorting path and issues motion instructions based on the sorting mark, the current position of the robot arm, and the status of the distribution channel; S4: Sorting is performed. The robotic arm 401 grabs the package according to the planned path. The pressure sensor 405 provides real-time feedback on the gripping force. If slippage is detected, the gripper resets. S5: Diversion and guidance: the guide plate 501 rotates to the target angle, and the pneumatic push rod 502 applies thrust according to the weight of the package to push the package to the designated diversion channel; S6, exception handling: if a path conflict or equipment failure is detected during the sorting process, the central controller 6 starts the dynamic adjustment program and reallocates the sorting tasks.

[0029] Specifically, the optimal sorting path in S3 must meet the following requirements: the angular velocity of the robot arm joint does not exceed the rated value, and the sorting action time is ≤1.5 seconds. The dynamic adjustment program in S6 trains the LSTM neural network through historical data to predict sorting congestion and adjust the path priority in advance.

[0030] More specifically, in this embodiment, during the merging stage, the photoelectric sensor array 20 detects the distance between packages. If the distance between three consecutive packages is less than 25 cm, the central controller 6 sends an instruction to reduce the speed of the upstream conveyor belt to 80% of the original speed and adjust the opening and closing angle of the baffle 202 to 60° for 5 seconds before recovery. After the sorting signal is input and the multi-spectral camera 301 recognizes the barcode, if the RFID reader 302 does not read a matching tag within 0.5 seconds, the package is marked as "pending manual review" and assigned to an abnormal channel. For path planning, the central controller 6 generates the shortest grasping path based on the idle state of the target distribution channel (feedback by the diversion guide device 5) and the current position of the robot arm, and confirms the location of the package. Ensure that the joint angular velocity does not exceed the rated value (such as the maximum angular velocity of joint 1 is 180° / s); during sorting execution, when the robot arm 401 grabs the package, the pressure sensor 405 monitors the clamping force in real time. If the clamping force drops by more than 15% within 0.2 seconds, it is judged as slippage, triggering the clamp to reclose and an alarm; diversion guidance, the guide plate 501 rotates to the target angle 0.5 seconds in advance (for example, the angle corresponding to the diversion channel 3 is 45°), and the pneumatic push rod 502 applies thrust when the package reaches the end of the guide plate to ensure that the pushing distance is ≥30cm; exception handling, if the same diversion channel fails to sort for three consecutive times, the central controller 6 automatically marks the channel as "faulty" and reallocates subsequent packages to the backup channel.

[0031] In this invention, photoelectric sensors and encoders are connected to a PLC via a CAN bus (baud rate of 1Mbps), while servo motors and pneumatic valves communicate with the PLC via the EtherCAT protocol. This invention provides an efficient and high-precision sorting control system and method for express delivery sorting machines. Through the coordinated control of a multispectral camera, an RFID reader / writer, a dynamic merging device, and an intelligent robotic arm, combined with improved AI algorithms and LSTM neural network prediction, this system achieves automated optimization of the entire package process, from merging to sorting and diverting. The system supports real-time load regulation and abnormality self-repair, further improving sorting efficiency and reducing error rates, making it suitable for deployment and widespread use in express delivery hubs.

[0032] It will be understood that the present invention is described by way of some embodiments, and it will be appreciated by those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are intended to be protected by the present invention.

Claims

1. A sorting control system for an express sorting machine, comprising a sorting machine body (1), a merging device (2) installed at the entrance side of the sorting machine body (1), a sorting signal acquisition device (3) arranged in sequence along the conveying direction of the sorting machine body (1), a sorting execution device (4) and a diversion guide device (5), characterized in that: The sorting machine body (1) comprises a plurality of parallel conveyor belts (101), each conveyor belt (101) is provided with a speed sensor (102) and a position encoder (103), and the conveyor belts (101) are driven by a variable frequency motor (104).

2. A sorting control system for an express sorting machine according to claim 1, characterized in that: In the control system: A merging device (2) is provided at the entrance side of the sorting machine main body (1), and comprises a photoelectric sensor array (201) and an adjustable baffle (202), wherein the photoelectric sensor array (201) detects the distance between packages and feeds back a signal to the central controller (6), and the adjustable baffle (202) controls the opening and closing angles via a first servo motor (203) to adjust the flow rate of packages entering the sorting machine main body (1); A sorting signal acquisition device (3) is installed above the sorting machine body (1) at a distance of 2-3 meters from the entrance, and includes a multispectral camera (301) and an RFID reader (302). The multispectral camera (301) is used to identify the size, shape and surface barcode of the package, and the RFID reader (302) communicates with the electronic tag on the package to obtain destination information. A sorting execution device (4) is located 1.5-2 meters downstream of the sorting signal acquisition device (3), and includes a six-degree-of-freedom robotic arm (401) and a gripper unit (402). The six-degree-of-freedom robotic arm (401) is connected to a second servo motor (404) via a harmonic reducer (403). The gripper unit (402) has a built-in pressure sensor (405) and is covered with a flexible material. A diversion guide device (5) is provided at the end of the sorting machine body (1), comprising a rotatable guide plate (501) and a pneumatic push rod (502), wherein the rotatable guide plate (501) is driven to rotate by a stepping motor (503), and the thrust of the pneumatic push rod (502) is dynamically adjusted according to the weight of the package; The central controller (6) is electrically connected to the sorting machine body (1), the merging device (2), the sorting signal acquisition device (3), the sorting execution device (4) and the diversion guide device (5), and has a built-in path planning algorithm and a dynamic adjustment program for coordinating the actions of each device and generating sorting instructions.

3. A sorting control system for an express sorting machine according to claim 2, characterized in that: The photoelectric sensor array (201) of the merging device (2) is composed of two rows of staggered infrared sensors with a horizontal spacing of 10 cm and a vertical spacing of 20 cm, and is used to detect the three-dimensional position of the package; The servo motor (203) of the adjustable baffle (202) uses an absolute encoder to feedback the position, the baffle opening and closing angle range is 0°-90°, and the response time is ≤50ms.

4. A sorting control system for an express sorting machine according to claim 2, characterized in that: The multispectral camera (301) is installed at a height of 1.2-1.5 meters, with an inclination angle of 30°-45°, and its lens faces the direction of the package entering the conveyor belt (101); The RFID reader (302) has an operating frequency of 860-960 MHz, a reading and writing distance of 0.5-1 meter, and synchronizes data with the multispectral camera (301) via a timestamp.

5. A sorting control system for an express sorting machine according to claim 2, characterized in that: The servo motor (404) of the robotic arm (401) has a maximum load of 15 kg and a repeatability accuracy of ±0.05 mm; The pressure sensor (405) of the gripper unit (402) has a measuring range of 0-100N, and the detection signal is transmitted to the central controller (6) via the CAN bus.

6. A sorting control system for an express sorting machine according to claim 2, characterized in that: The surface of the guide plate (501) of the diversion guide device (5) is covered with a polyurethane buffer layer, and the rotation angle is calculated by the central controller (6) according to the target diversion channel position, and the angle error is ≤1°; the maximum thrust of the pneumatic push rod (502) is 200N, and the thrust value is proportional to the weight of the package and is adjusted in real time through the PID algorithm.

7. A sorting control system for an express sorting machine according to claim 2, characterized in that: The central controller (6) adopts an industrial-grade PLC and industrial control collaborative architecture, and its path planning algorithm is an improved AI algorithm that combines the kinematic constraints of the robot arm and the sorting priority to dynamically generate an obstacle avoidance path.

8. A sorting control method for an express sorting machine, comprising a sorting control system for an express sorting machine according to any one of claims 1 to 7, characterized in that: The steps include: S1, merging stage, detecting the distance between inlet packages through the photoelectric sensor array (201), if the distance is less than a set threshold (20-30 cm), reducing the speed of the upstream conveyor belt or adjusting the opening and closing angle of the baffle (202); S2, sorting signal input, multispectral camera (301) identifies the parcel barcode and size, RFID reader (302) obtains destination information, and generates a unique sorting identifier after data fusion; S3, path planning, the central controller (6) calculates the optimal sorting path and issues motion instructions based on the sorting mark, the current position of the robot arm and the status of the distribution channel; S4, sorting is executed, the robotic arm (401) grabs the package according to the planned path, the pressure sensor (405) provides real-time feedback of the gripping force, and triggers the gripper to reset if slippage is detected; S5, diversion and guidance, the guide plate (501) rotates to the target angle, and the pneumatic push rod (502) applies thrust according to the weight of the package to push the package to the designated diversion channel; S6, exception handling, if a path conflict or equipment failure is detected during the sorting process, the central controller (6) starts the dynamic adjustment program and reallocates the sorting tasks.

9. A sorting control method for an express sorting machine according to claim 8, characterized in that: The optimal sorting path in S3 must meet the following requirements: the angular velocity of the robot arm joint does not exceed the rated value, and the sorting action time is ≤1.5 seconds.

10. A sorting control method for an express sorting machine according to claim 8, characterized in that: The dynamic adjustment program in S6 trains the LSTM neural network through historical data to predict sorting congestion and adjust the path priority in advance.

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