AGV single path scheduling system based on PLC

Abstract

The invention discloses an AGV trolley single path scheduling system based on a PLC, and the system comprises an AGV trolley which is used for taking, placing and transporting goods, a PLC controller which is located in the AGV trolley, a communication module, a detection module and a remote control module, and the AGV trolley is scheduled based on the PLC controller to execute and complete a task. The invention aims to provide the AGV trolley single path scheduling system based on the PLC, and the AGV trolley can be used in a scene with a relatively complex working condition and a relatively small number of AGVs, and is low in cost.

Description

Technical Field

[0001] This invention relates to the field of AGV (Automated Guided Vehicle) vehicles, specifically a PLC-based single-path scheduling system for AGV vehicles. Background Technology

[0002] Automated Guided Vehicles (AGVs) have become crucial equipment in automated logistics and intelligent manufacturing systems. Demand for them in industries such as electronics assembly, automobile manufacturing, and logistics is experiencing explosive growth in China, indicating a promising future. As AGVs are widely used in production and daily life, their application scenarios are becoming increasingly complex. Currently, most AGV controllers on the market are dedicated AGV controllers, and their scheduling systems are not sold separately. They must be paired with dedicated AGV controllers, resulting in higher costs and making them unsuitable for scenarios with a small number of AGVs and complex operating conditions. Summary of the Invention

[0003] The purpose of this invention is to provide a PLC-based AGV single-path scheduling system. The AGV of this invention can be used in scenarios with complex working conditions and a small number of AGVs, and it is low in cost.

[0004] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0005] A PLC-based AGV single-path scheduling system includes an AGV for picking up, placing and transporting goods, a PLC controller located inside the AGV, a communication module, a detection module and a remote control module, and the AGV is scheduled to perform tasks based on the PLC controller.

[0006] The detection module includes a lidar, a QR code sensor, and an inertial sensor, which are mounted on the AGV (Automated Guided Vehicle).

[0007] The AGV single-path scheduling system also includes workshop A and workshop B, with a cargo transportation path between workshop A and workshop B, and multiple branch paths on the cargo transportation path.

[0008] Workshop A has a warehouse goods placement area, a charging area, and a standby area. Workshop B has multiple workstations. The warehouse goods placement area, charging area, standby area, and workstations are all located on a branch of the goods transportation path. There are also avoidance points on the branch paths for multiple AGV vehicles to pass when they meet. There is a unique branch between each workstation and the goods transportation path.

[0009] When an AGV (Automated Guided Vehicle) encounters another vehicle on the transport route, the PLC controller schedules the AGV based on the priority of the task it is currently performing.

[0010] The remote control module includes a display screen, a pager, and an MQTT server (host computer). The display screen is located in workshop A, the MQTT server is fixed in the warehouse goods placement area of ​​workshop A, and the pager is fixed at the workstation in workshop B. Each workstation in workshop B has a unique route for goods transportation between workshop A and workshop B.

[0011] The display screen includes a Weintek touch screen, which displays the goods placement information of the warehouse goods placement area in Workshop A. The PLC controller obtains the goods placement information of the warehouse goods placement area in Workshop A from the Weintek touch screen via S7 communication.

[0012] The remote control module also includes a charging pile, which is located in the charging area. The AGV is charged or in standby mode in the charging area or standby area.

[0013] The communication module includes a local area network (LAN) formed by a TP-LINK router mesh network, S7 communication, and MQTT communication. The communication module, charging module, detection module, and remote control module are all located within the same LAN. The PLC controller connects and communicates wirelessly with the charging pile, Weintek touch screen, pager, and MQTT server. The PLC controller communicates with the pager and MQTT server via MQTT communication, and with the charging pile and Weintek touch screen via S7 communication.

[0014] Compared with existing technologies, the PLC-based AGV single-path scheduling system that adopts the above technical solution has the following advantages:

[0015] 1. The PLC-based AGV single-path scheduling system of the present invention schedules the task execution and mutual avoidance of AGVs through the PLC controller, which is low cost.

[0016] 2. The AGV of the present invention is particularly suitable for scenarios with complex working conditions. It can freely switch between manual and automatic modes and set timed tasks at any time.

[0017] 3. When the path is relatively simple or unique, the scheduling system of the present invention can solve the problem that multiple AGVs cannot work at the same time, and provides a solution for multiple AGVs to avoid obstacles and allocate tasks on a single path. Attached Figure Description

[0018] Figure 1 This is a flowchart of the AGV (Automated Guided Vehicle) transportation process.

[0019] Figure 2 Flowchart for prioritizing tasks performed by AGVs.

[0020] Figure 3 Flowchart for assigning tasks to GV vehicles.

[0021] Figure 4 Communication method diagram for AGV single-path scheduling system

[0022] Figure 5 Schematic diagram of AGV transport path

[0023] Attached label: 1. Standby area; 2. Charging area; 3. Warehouse goods placement area; 4. Clearance point; 5. Workstation. Detailed Implementation

[0024] The present invention will now be further described with reference to the accompanying drawings.

[0025] like Figures 1 to 5 As shown, a PLC-based AGV single-path scheduling system includes an AGV for picking up, placing and transporting goods, a PLC controller located inside the AGV, a communication module, a detection module and a remote control module.

[0026] The detection module includes a lidar, a QR code sensor, and an inertial sensor, all mounted on the AGV (Automated Guided Vehicle). The lidar detects obstacles ahead, the inertial sensor detects the angular deviation between the vehicle's current state and the positive direction of the QR code, and corrects the vehicle's course accordingly. The QR code sensor scans QR codes pasted along the cargo transport path for navigation; each QR code contains a number and direction, and the number determines the vehicle's location. After scanning a QR code, the AGV's location information is updated in real time, and the location information of other AGVs is periodically retrieved. Since the cargo transport path is unique, the location of each AGV indicates its transport progress and whether it is fully loaded. The remote control module includes a display screen, a pager, and an MQTT server (host computer). The display screen is located in workshop A, and the MQTT server is fixed in the warehouse cargo placement area of ​​workshop A. The MQTT server sends task information to multiple AGVs, and the AGVs execute transport tasks based on the number of tasks and the order of pager calls. The pager is fixed at a workstation in workshop B, and each workstation in workshop B has a unique route for cargo transport between workshop A and workshop B.

[0027] The display screen includes a Weintek touch screen, which displays the goods placement information of the warehouse goods placement area in Workshop A. The PLC controller obtains the goods placement information of the warehouse goods placement area in Workshop A from the Weintek touch screen via S7 communication.

[0028] The remote control module also includes a charging pile, which is located in the charging area. The AGV is charged or in standby mode in the charging area or standby area.

[0029] like Figure 4As shown, the communication module includes a local area network (LAN) formed by a TP-LINK router using a mesh network, S7 communication, and MQTT communication. The communication module, charging module, detection module, and remote control module are all located within the same LAN. The PLC controller connects and communicates wirelessly with the charging pile, Weintek touchscreen, pager, and MQTT server. The PLC controller communicates with the pager and MQTT server via MQTT communication, and with the charging pile and Weintek touchscreen via S7 communication.

[0030] like Figure 5 As shown, the AGV single-path scheduling system also includes workshop A and workshop B, with a cargo transportation path between them. This cargo transportation path has multiple branch paths. Workshop A includes a warehouse cargo placement area, a charging area, and a standby area. The warehouse cargo placement area includes areas for empty and full cargo frames. Workshop B has multiple workstations. The warehouse cargo placement area, charging area, standby area, and workstations are all located on branch paths of the cargo transportation path. These branch paths also have avoidance points for multiple AGVs to navigate when they meet. Each workstation has a unique branch path connecting it to the cargo transportation path, ensuring accurate delivery of goods to the workstation where the call button that issued the instruction is located.

[0031] When an AGV needs to perform more than one task, since there is only one branch between the AGV's standby area and the workstation, and the cargo transportation paths of all branches overlap, if multiple AGVs are performing tasks at the same time, they must wait for the AGV that was performing the task first to reach the specific workstation. Otherwise, the AGVs will collide on the cargo transportation path and will not be able to continue performing the task.

[0032] When a fully loaded AGV leaves the warehouse goods placement area of ​​workshop A, an empty AGV is simultaneously returning to the standby area of ​​workshop A. There is an overlap between fully loaded and empty AGVs, and the task priority of the fully loaded AGV is higher than that of the empty AGV.

[0033] The AGV also has a manual mode, which is a non-working mode. In manual mode, it executes actions according to the instructions issued by the Weintek touch screen. It can also transport goods to the B workshop workstation. It does not navigate according to the QR code, but adjusts the forward direction, stop and turn of the AGV according to the Weintek touch screen.

[0034] The AGV (Automated Guided Vehicle) determines whether it needs charging by reading the battery level. When the AGV's battery is low, it communicates with the PLC controllers of multiple AGVs and checks the positions of the multiple AGVs to determine if there are any obstructions between its current position and the charging area. If there are other AGVs between the AGV needing charging and the charging area, the PLC controller of the AGV needing charging sends a command to the PLC controllers of the other AGVs, causing the obstructing AGV to move away and the AGV needing charging to enter the charging area for normal charging. If there are no obstructing AGVs, the AGV needing charging goes directly to the charging area to charge.

[0035] like Figure 1 As shown, the PLC controller schedules the AGV to complete the task through the communication module, detection module, and remote control module.

[0036] In automatic mode, after the AGV has completed power-on initialization, it has no task and sufficient power. It waits in the standby area for the caller and MQTT server to send task information via MQTT communication. Upon receiving the task instruction from the caller, the AGV transports goods from the warehouse in workshop A to the workstation in workshop B. If there is an empty cargo box at the workstation, the AGV pulls the empty cargo box back to the empty cargo box placement area in the warehouse of workshop A when returning to the standby area. The working steps of the AGV's transportation process are shown in steps (1) to (9):

[0037] Step (1): Call the PLC controller of the AGV car at the workstation in workshop B via the call button;

[0038] Step (2): The goods placement information in the warehouse goods placement area of ​​workshop A is transmitted to the PLC controller through Weintek touch screen communication to monitor whether there are goods in the warehouse of workshop A.

[0039] Step (3): If the warehouse of workshop A has the specified goods, the AGV will perform the specified task; if the warehouse of workshop A does not have the specified goods, the AGV will not perform the task and will issue a warning. The caller will change its color status to convey to the caller that there are no goods in the warehouse of workshop A. After the warehouse of workshop A replenishes the specified goods, the AGV will perform the specified task.

[0040] Step (4): After the AGV picks up the goods by performing the designated task, the QR code sensor on the AGV scans the QR code pasted on the goods transportation path for navigation. The forward direction and deflection angle of the AGV are obtained by scanning the QR code. The QR code number is sent to the PLC controller. The PLC controller determines the current position and updates the position information according to the QR code number. It also checks whether the route to the B workshop workstation is blocked.

[0041] Step (5): If there is a blockage, the AGV will stop moving and issue a warning. The call button will change color status. After confirming that the obstacles on the route of the AGV to the workstation in workshop B have been cleared, the call button will issue a forward command and the AGV will transport the goods to the designated location. If there is no blockage, the AGV will transport the goods to the designated workstation in workshop B.

[0042] Step (6): After the AGV trolley puts down the goods, determine whether there is an empty cargo box at the B workshop workstation;

[0043] Step (7): If there is an empty container, the AGV will return the empty container to the warehouse of workshop A; if there is no empty container, the AGV will return to the warehouse of workshop A.

[0044] Step (8): Monitor whether all tasks have been completed and whether the AGV has sufficient power.

[0045] Step (9): If the battery is sufficient and there is a task, proceed to step (2); if the battery is insufficient but there is a task to be performed, charge the battery and proceed to step (2) after the battery is sufficient; if the battery is sufficient and there is no task, the AGV enters standby mode and the caller status changes to callable state; if the battery is insufficient and there is no task, charge the battery and the AGV enters standby mode after the battery is sufficient and the caller status changes to callable state.

[0046] like Figure 2 As shown, when multiple AGVs meet on the cargo transport path, the PLC controller schedules them according to the priority of the tasks currently being performed by the AGVs. The steps for prioritizing tasks performed by the AGVs are shown in steps (11) to (20):

[0047] Step (11): Multiple AGVs transport goods simultaneously.

[0048] Step (12): The AGV vehicle updates its location information in real time and periodically obtains the location information of the AGV vehicle.

[0049] Step (13): Monitor whether there is an intersection in the forward path of the AGV;

[0050] In step (14), if there is no intersection, the AGV car proceeds to step (20); if there is an intersection, it is determined whether the AGV cars are in the same direction.

[0051] If the directions are the same, proceed to step (16); otherwise, proceed to step (17).

[0052] Step (16): Determine whether the AGVs that intersect are in front or behind. If they are in front, proceed to step (20). If they are behind, stop and wait for the AGVs in front to enter the branch system before proceeding to step (20).

[0053] Step (17): Determine whether the AGV is a fully loaded AGV.

[0054] Step (18): If it is a non-full-loaded AGV, the non-full-loaded AGV drives into the avoidance point and waits for the full-loaded AGV to leave before returning to the warehouse of workshop A to end the task; if it is a full-loaded AGV, determine whether the non-full-loaded AGV should avoid it.

[0055] Step (19): If the non-full-loaded AGV has already yielded, the AGV proceeds to step (20); if the non-full-loaded AGV has not yielded, stop and wait for the non-full-loaded AGV to enter the yielding point before proceeding to step (20).

[0056] Step (20): The AGV continues to perform its task.

[0057] like Figure 3 As shown, when the call buttons at the workstations send tasks simultaneously, the AGV (Automated Guided Vehicle) executes the transportation task based on the number of tasks and the order of the calls. The AGV task allocation process is shown in steps (21)-(24):

[0058] Step (21), the pager sends information.

[0059] Step (22): Monitor whether the AGV is charging;

[0060] Step (23): If no AGV is charging, the AGV closest to the warehouse will perform the task first; if an AGV is charging, determine whether the AGV's battery level is below 30%.

[0061] Step (24): If the battery level of all AGVs is below 30%, the AGVs will continue to charge and will not perform any tasks. The caller will not be able to send any information. If the battery level of any AGV is above 30%, the AGV that is not charging and has a battery level above 30% will be given priority to perform tasks.

[0062] The above description is a preferred embodiment of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the principle of the present invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. A PLC-based AGV single-path scheduling system, characterized in that, It includes AGVs for picking up, placing and transporting goods, a PLC controller located inside the AGV, a communication module, a detection module and a remote control module, and the PLC controller schedules the AGVs to perform tasks.

2. The AGV single-path scheduling system according to claim 1, characterized in that, The detection module includes a lidar, a QR code sensor, and an inertial sensor, which are mounted on the AGV (Automated Guided Vehicle).

3. The AGV single-path scheduling system according to claim 1, characterized in that, It also includes workshop A and workshop B, with a cargo transportation route between workshop A and workshop B, and multiple branch roads on the cargo transportation route.

4. The AGV single-path scheduling system according to claim 2, characterized in that, Workshop A has a warehouse goods placement area, a charging area, and a standby area. Workshop B has multiple workstations. The warehouse goods placement area, charging area, standby area, and workstations are all located on a branch of the goods transportation path. There are also avoidance points on the branch paths for multiple AGV vehicles to pass when they meet. There is a unique branch between each workstation and the goods transportation path.

5. The AGV single-path scheduling system according to claim 3, characterized in that, When an AGV (Automated Guided Vehicle) encounters another vehicle on the transport route, the PLC controller schedules the AGV based on the priority of the task it is currently performing.

6. The AGV single-path scheduling system according to claim 3, characterized in that, The remote control module includes a display screen, a pager, and an MQTT server. The display screen is located in workshop A, the MQTT server is fixed in the warehouse goods placement area of ​​workshop A, and the pager is fixed at the workstation in workshop B.

7. The AGV single-path scheduling system according to claim 6, characterized in that, The display screen includes a Weintek touchscreen, which displays cargo placement information for the warehouse cargo placement area in Workshop A.

8. The AGV single-path scheduling system according to claim 7, characterized in that, The remote control module also includes a charging station, which is located in the charging area.

9. The AGV single-path scheduling system according to claim 8, characterized in that, The communication module includes a local area network formed by a TP-LINK router in a mesh network, S7 communication and MQTT communication. The PLC controller connects and communicates wirelessly with the charging pile, Weintek touch screen, pager and MQTT server. The PLC controller communicates with the pager and MQTT server based on MQTT communication. The PLC controller communicates with the charging pile and Weintek touch screen based on S7 communication.

10. The AGV single-path scheduling system according to claim 9, characterized in that, The working steps of the AGV trolley transportation process are shown in steps (1) to (9): Step (1): Call the PLC controller of the AGV car at the workstation in workshop B via the call button; Step (2): The goods placement information in the warehouse goods placement area of ​​workshop A is transmitted to the PLC controller through Weintek touch screen communication to monitor whether there are goods in the warehouse of workshop A. Step (3): If the warehouse of workshop A has the specified goods, the AGV will perform the specified task; if the warehouse of workshop A does not have the specified goods, the AGV will not perform the task and will issue a warning. The caller will change its color status to convey to the caller that there are no goods in the warehouse of workshop A. After the warehouse of workshop A replenishes the specified goods, the AGV will perform the specified task. Step (4): After the AGV picks up the goods by performing the designated task, the QR code sensor on the AGV scans the QR code pasted on the goods transportation path for navigation. The forward direction and deflection angle of the AGV are obtained by scanning the QR code. The QR code number is sent to the PLC controller. The PLC controller determines the current position and updates the position information according to the QR code number. It also checks whether the route to the B workshop workstation is blocked. Step (5): If there is a blockage, the AGV will stop moving and issue a warning. The call button will change color status. After confirming that the obstacles on the route of the AGV to the workstation in workshop B have been cleared, the call button will issue a forward command and the AGV will transport the goods to the designated location. If there is no blockage, the AGV will transport the goods to the designated workstation in workshop B. Step (6): After the AGV trolley puts down the goods, determine whether there is an empty cargo box at the B workshop workstation; Step (7): If there is an empty cargo box, the AGV will return the empty cargo box to the warehouse of workshop A. If there are no empty cargo boxes, the AGV will return to the warehouse in workshop A. Step (8): Monitor whether all tasks have been completed and whether the AGV has sufficient power. Step (9): If the battery is sufficient and there is a task, proceed to step (2); if the battery is insufficient but there is a task to be performed, charge the battery and proceed to step (2) after the battery is sufficient; if the battery is sufficient and there is no task, the AGV enters standby mode and the caller status changes to callable state; if the battery is insufficient and there is no task, charge the battery and the AGV enters standby mode after the battery is sufficient and the caller status changes to callable state.

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