Communication control method for PLC and third-party AGV equipment

Abstract

The invention discloses a PLC and third-party AGV equipment communication control method, and relates to the technical field of communication, the PLC and third-party AGV equipment communication control method comprises a PLC system and an AGV system, a material carrying-in communication interaction subprogram and a material carrying-out communication interaction subprogram are written in the PLC system and the AGV system, and the subprograms comprise a strategy for judging whether to call the current communication interaction subprogram or not. The communication control method for the PLC and the third-party AGV equipment is simple in implementation process, and can be implemented by directly writing a material carrying-in communication interaction subprogram and a material carrying-out communication interaction subprogram in a PLC program and a third-party AGV equipment program and judging whether the communication interaction subprograms are called or not, other peripheral hardware equipment does not need to be configured, and the implementation process is simple. The communication interaction result is stable and reliable, and the method is suitable for PLCs and AGVs of all brands.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a method for controlling communication between a PLC and a third-party AGV device. Background Art

[0002] In recent years, the manufacturing industry has been continuously transforming and upgrading to build smart factories. Warehousing logistics connects material supply and production. The intelligent logistics between warehouses, workshops, and production lines is crucial to the realization of smart factories, and materials inside the factory are often completed through AGV. Since the production process is divided into multiple processes and there are various automation equipment, generally a complete intelligent production line is composed of multiple automation equipment or multiple subsystems. When there is a handover between the automation equipment and AGV, they need to cooperate with each other. The controller of the automation equipment control system generally uses PLC. When the AGV system transports materials to the line-side automation equipment, the PLC system and the AGV system need to communicate interactive signals.

[0003] At present, the material transportation interaction process is generally that the PLC system generates a signal to allow transportation in the communication program block when the conditions are met, and the AGV system feeds back the transportation completion signal to the PLC system after the transportation is completed. However, this communication interaction method is usually unstable, especially when the AGV system communicates and interacts with multiple devices or multiple systems (i.e., multiple PLC systems), and when abnormal alarms or shutdowns occur during the equipment interaction process. When the transportation of materials requires interactive data information (material type, quantity, etc.), the situation is more complicated. The PLC control systems of equipment from different manufacturers have their own communication program blocks and there is no unified standard. The reliability and correctness of the communication control interaction program between PLC and AGV equipment has become the key to effective cooperation between equipment.

[0004] In summary, the prior art similar to the above has the following two shortcomings: 1. The communication control interaction method between PLC and third-party AGV equipment is usually unstable, and the sent data is incomplete or lost.

[0005] 2. The PLC control systems of equipment from different manufacturers interact with third-party AGV equipment with their own communication program blocks, without unified standards, long debugging cycles, and low efficiency. Later maintenance personnel need to learn and understand the communication program blocks of each device, which is time-consuming and has high maintenance costs.

[0006] Therefore, it is urgent to improve this shortcoming. The present invention studies and improves the existing technology and its shortcomings, and provides a communication control method between a PLC and a third-party AGV device. Summary of the invention

[0007] The purpose of the present invention is to provide a method for controlling communication between a PLC and a third-party AGV device to solve the problems raised in the above-mentioned background technology.

[0008] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a method for controlling communication between a PLC and a third-party AGV device, which is used for material transfer. The material transfer process is divided into two situations: material moving in and moving out. The method includes a PLC (programmable logic controller) system and an AGV (automatic guided vehicle) system. Both the PLC system and the AGV system are internally programmed with a material moving-in communication interaction subroutine and a material moving-out communication interaction subroutine, and the subroutine includes a strategy for determining whether to call the current communication interaction subroutine.

[0009] Furthermore, the PLC system serves as a control center, responsible for processing requests from the AGV system and feeding back corresponding status information.

[0010] Furthermore, the AGV system serves as an execution unit, responsible for sending requests to the PLC system and receiving feedback from the PLC system.

[0011] Furthermore, the material moving-in communication interaction subroutine in the PLC system: the PLC system needs to add 5 interactive data variables, namely move-in request MoveIn_Request (bool type), admission MoveIn_AdmissionIn (bool type), move-in completion confirmation MoveIn_FinishAffirm (bool type), material type MoveIn_Type (String type), and material quantity MoveIn_Quantity (Int type).

[0012] Furthermore, the material moving-in communication interaction subroutine in the AGV system: the AGV system needs to add 4 interactive data variables, namely, request to enter MoveIn_RequestIn (bool type), moving-in completion MoveIn_Finish (bool type), material type MoveIn_Type (String type), and material quantity MoveIn_Quantity (Int type).

[0013] Furthermore, the material moving-in communication interaction subroutine process steps are as follows: S1, PLC and AGV equipment automatically start running; S2, the detection program determines whether the workstation is short of materials and needs to be moved in. If necessary, proceed to step S3, if not, re-test; S3, entering the communication interaction subroutine; S4, PLC sends a move-in request Move In_Request; S5, AGV feedback request enters MoveIn_RequestIn; S6, PLC sends permission to enter MoveIn_AdmissionIn; S7, AGV sends MoveIn_Finish; S8, AGV sends the material type MoveIn_Type and quantity MoveIn_Quantity; S9, PLC feedback the type of material moved in MoveIn_Type and the quantity MoveIn_Quantity; S10, PLC feedback MoveIn_FinishAffim confirmation; S11, the communication interaction process ends and the next task is entered, and the cycle continues to step S2.

[0014] Furthermore, the material moving-out communication interaction subroutine in the PLC system: the PLC system needs to add 5 interactive data variables, namely, move-out request MoveOut_Request (bool type), move-out permission MoveOut_AdmissionIn (bool type), move-out completion confirmation MoveOut_FinishAffirm (bool type), material type MoveOut_Type (String type), and material quantity MoveOut_Quantity (Int type).

[0015] Furthermore, the material moving-out communication interaction subroutine of the AGV system: the AGV system needs to add four interactive data variables, namely, move-out request MoveOut_RequestIn (bool type), move-out completion MoveOut_Finish (bool type), move-out material type MoveOut_Type (String type), and quantity MoveOut_Quantity (Int type).

[0016] Furthermore, the material moving out communication interaction subroutine process steps are as follows: S1, PLC and AGV equipment automatically start running; S2, the detection program determines whether the station is full of materials and needs to be moved out. If necessary, it goes to step S3. If not, it re-detects; S3, entering the moving-out communication interaction subroutine; S4, PLC sends a move-out request MoveOut_Request; S5, AGV feedback request enters MoveOut_RequestIn; S6, PLC sends permission to enter MoveOut_AdmissionIn; S7, PLC sends the material type MoveOut_Type and quantity MoveOut_Quantity; S8, AGV sends MoveOut Finish; S9, AGV feedback the type of material moved out MoveOut_Type, quantity MoveOut_Quantity; S10, PLC feedback MoveOut_FinishAffirm; S11, the communication interaction process ends and the next task is entered, and the cycle continues to step S2.

[0017] The present invention provides a method for controlling communication between a PLC and a third-party AGV device, which has the following beneficial effects: 1. This control method has a simple implementation process, strong applicability, high compatibility, and complete interactive data. It is not restricted by PLC and AGV brands. It has obvious advantages in workshop-level intelligent logistics application scenarios with multiple manufacturers and multiple systems. It can unify standards, shorten debugging time, improve efficiency, and reduce maintenance costs.

[0018] 2. The material moving-in communication interaction subroutine and the material moving-out communication interaction subroutine of this control method can be called repeatedly to achieve the docking of different handling stations in this PLC system with multiple AGV devices, or the docking of this AGV device with different handling stations in multiple PLC systems.

[0019] In summary, the implementation process of the present invention is simple. It can be achieved by directly writing the material moving-in communication interaction subroutine and the material moving-out communication interaction subroutine in the PLC program and the third-party AGV equipment program, and a strategy for determining whether to call the communication interaction subroutine. There is no need to configure other peripheral hardware devices. The communication interaction results are stable and reliable, and it is suitable for all brands of PLCs and AGVs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of a material moving-in communication interaction subroutine flow of a communication control method between a PLC and a third-party AGV device of the present invention; Figure 2 It is a schematic diagram of a material moving-out communication interaction subroutine flow of a communication control method between a PLC and a third-party AGV device of the present invention; Figure 3 This is a control system architecture diagram of a method for controlling communication between a PLC and a third-party AGV device according to the present invention. DETAILED DESCRIPTION

[0021] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0022] Embodiment 1 like Figure 1-Figure 2 As shown, a communication control method between a PLC and a third-party AGV device is used for material transfer, and the material transfer process is divided into two situations: material moving in and moving out, including a PLC (programmable logic controller) system and an AGV (automatic guided vehicle) system. The PLC system and the AGV system are both programmed with a material moving-in communication interaction subroutine and a material moving-out communication interaction subroutine, and the subroutine includes a strategy for determining whether to call the current communication interaction subroutine; In this embodiment, the PLC system, as a control center, is responsible for processing requests from the AGV system and feeding back corresponding status information. The AGV system, as an execution unit, is responsible for sending requests to the PLC system and receiving feedback from the PLC system.

[0023] In this embodiment, the material moving-in communication interaction subroutine includes: 1) Material moving-in communication interaction subroutine in the PLC system: Five interaction data variables need to be added in the PLC system, as follows: MoveIn_Request (bool type): initiated by the AGV system, indicating that the AGV is ready to move the material to the specified location. The PLC system reads this variable to determine whether there is a move-in task to be processed; MoveIn_AdmissionIn (bool type): sent by the PLC system, indicating that the PLC has confirmed that the AGV can start the move-in operation. The AGV system reads this variable and starts to execute the move-in action; MoveIn_FinishAffirm (bool): sent by the PLC system, indicating that the PLC has confirmed that the AGV has completed the move-in operation and the material has been placed correctly. The AGV system reads this variable to confirm that the move-in task is completed; Material type (MoveIn_Type, String type): Sent by the AGV system, indicating the type of material to be moved in. The PLC system reads this variable for subsequent processing or storage; Material quantity (MoveIn_Quantity, Int type): Sent by the AGV system, indicating the quantity of materials to be moved in. The PLC system reads this variable for inventory management or production scheduling.

[0024] 2) Material handling communication interaction subroutine in the AGV system: Four interaction data variables need to be added in the AGV system, as follows: Request to enter (MoveIn_RequestIn, bool type): Initiated by the AGV system, indicating that the AGV requests to start the move-in operation. The PLC system reads this variable to determine whether the AGV is allowed to move in; MoveIn_Finish (bool type): sent by the AGV system, indicating that the AGV has completed the move-in operation. The PLC system reads this variable to confirm whether the move-in task has been successfully completed; Material type (MoveIn_Type, String type): sent by the AGV system, indicating the type of material to be moved in. The PLC system reads this variable for subsequent processing; Material quantity (MoveIn_Quantity, Int type): Sent by the AGV system, indicating the quantity of materials to be moved in. The PLC system reads this variable for inventory management.

[0025] In this embodiment, the material moving-in communication interaction subroutine process steps are as follows: S1, PLC and AGV equipment automatically start running; S2, the detection program determines whether the workstation is short of materials and needs to be moved in. If necessary, proceed to step S3, if not, re-test; S3, entering the communication interaction subroutine; S4, PLC sends a move-in request Move In_Request; S5, AGV feedback request enters MoveIn_RequestIn; S6, PLC sends permission to enter MoveIn_AdmissionIn; S7, AGV sends MoveIn_Finish; S8, AGV sends the material type MoveIn_Type and quantity MoveIn_Quantity; S9, PLC feedback the type of material moved in MoveIn_Type and the quantity MoveIn_Quantity; S10, PLC feedback MoveIn_FinishAffim confirmation; S11, the communication interaction process ends and the next task is entered, and the cycle continues to step S2; In this embodiment, the material moving out communication interaction subroutine includes: 1) Material removal communication interaction subroutine in the PLC system: Five interaction data variables need to be added in the PLC system, as follows: MoveOut_Request (bool type): initiated by the AGV system, indicating that the AGV requests to move materials out of the specified location. The PLC system reads this variable to determine whether the move-out operation is allowed; MoveOut_AdmissionIn (bool type): sent by the PLC system, indicating that the PLC has confirmed that the AGV can start the move-out operation. The AGV system reads this variable and starts to execute the move-out action; MoveOut_FinishAffirm (bool): sent by the PLC system, indicating that the PLC has confirmed that the AGV has completed the move-out operation and the material has been correctly moved. The AGV system reads this variable to confirm that the move-out task is completed; Material type (MoveOut_Type, String): Sent by the AGV system (or provided by the PLC system in some cases, depending on the system design), indicating the type of material to be moved out. The PLC system reads this variable for subsequent processing or updating inventory information; Material quantity (MoveOut_Quantity, Int type): Sent by the AGV system (or provided by the PLC system in some cases), indicating the quantity of materials to be moved out. The PLC system reads this variable for inventory management or production scheduling; 2) AGV system material removal communication interaction subroutine: 4 interaction data variables need to be added in the AGV system, as follows: MoveOut_RequestIn (bool type): initiated by the AGV system, indicating that the AGV requests to start the move-out operation. The PLC system reads this variable to determine whether the AGV is allowed to move out. MoveOut_Finish (bool type): sent by the AGV system, indicating that the AGV has completed the move-out operation. The PLC system reads this variable to confirm whether the move-out task has been successfully completed; MoveOut_Type (String): Sent by the AGV system (or synchronized with the PLC system in some cases), indicating the type of material to be moved out, used to ensure that the AGV moves the correct material; Quantity (MoveOut_Quantity, Int type): sent by the AGV system (or synchronized with the PLC system in some cases), indicating the quantity of materials to be moved out, used to ensure that the quantity of materials moved by the AGV matches the request; In this embodiment, the material moving out communication interaction subroutine process steps are as follows: S1, PLC and AGV equipment automatically start running; S2, the detection program determines whether the station is full and needs to be moved out. If necessary, it goes to step S3. If not, it re-detects; S3, entering the moving-out communication interaction subroutine; S4, PLC sends a move-out request MoveOut_Request; S5, AGV feedback request enters MoveOut_RequestIn; S6, PLC sends permission to enter MoveOut_AdmissionIn; S7, PLC sends the material type MoveOut_Type and quantity MoveOut_Quantity; S8, AGV sends MoveOut Finish; S9, AGV feedback the type of material moved out MoveOut_Type, quantity MoveOut_Quantity; S10, PLC feedback MoveOut_FinishAffirm; S11, the communication interaction process ends and the next task is entered, and the cycle continues to step S2; Embodiment 2 like Figure 3 As shown, the control system of a certain automobile welding workshop can be mainly divided into a floor control system, a left side control system, a right side control system, a left door control system, a right door control system, a top cover control system and a main line control system according to the function and process division. There is a handover between the systems, but they are manufactured by different suppliers. All systems use Siemens S7-1500PLC. More than 50 AGVs are used to transport and transfer materials from various systems in the entire welding workshop. Since the PLCs of equipment from different manufacturers in each process division need to communicate with the AGV, in order for each manufacturer to establish a unified standard, improve debugging efficiency, and reduce later maintenance costs, this embodiment adopts a unified control interaction method in the process of communication between each PLC and the third-party AGV equipment. The PLC system and the AGV system are both programmed with a material moving-in communication interaction subroutine and a material moving-out communication interaction subroutine as well as a strategy for determining whether to call the communication interaction subroutine. The logistics pulling process of the loading and unloading positions of the floor control system is illustrated as follows: In this embodiment, the steps of the material moving-in process are as follows: S1. When the floor line PLC system detection program determines that the loading position is short of material, it enters the material moving-in communication interaction subroutine; S2, the PLC system sends a MoveIn_Request signal to the AGV system; S3. After receiving the signal from step S2, the AGV system dispatches an idle AGV body to transfer the materials required by the loading position to the loading waiting position, and feeds back a request to enter the MoveIn_RequestIn signal to the PLC system; S4, after the PLC system passes the self-check, it sends the MoveIn_AdmissionIn signal to the AGV system to allow entry; S5. After the AGV system receives the signal from step S4, the AGV body transfers the materials required for the loading position to the loading position, and sends a MoveIn_Finish signal, material type MoveIn_Type, and material quantity MoveIn_Quantity to the PLC system; S6. After receiving the signal from step S5, the PLC system feeds back the material type MoveIn_Type and material quantity MoveIn_Quantity, as well as the MoveIn_FinishAffirm signal to the AGV system; S7. After the AGV system receives the signal in step S6 and verifies that it is correct, the AGV body leaves the loading position, completing the material loading action.

[0026] In this embodiment, the material removal process steps are as follows: S1. When the floor line PLC system detection program determines that the material level is full, it enters the material removal communication interaction subroutine; S2, the PLC system sends a MoveOut_Request signal to the AGV system; S3. After receiving the signal from step S2, the AGV system dispatches an idle AGV body to the unloading waiting position, and feeds back a request to enter the MoveOut_RequestIn signal to the PLC system; S4, after the PLC system passes the self-check, it sends the AGV system a MoveOut_AdmissionIn signal to allow entry, as well as the material type MoveOut_Type and the material quantity MoveOut_Quantity; S5. After the AGV system receives the signal from step S4, the AGV body enters the unloading position to move the material to the unloading waiting position, and feeds back MoveOut_Finish, the type of material to be moved out, and MoveOut_Quantity to the PLC system; S6. After the PLC system receives the signal from step S5 and verifies that it is correct, it sends a MoveOut_FinishAffirm signal to the AGV system; S7. After the AGV system receives the signal from step S6, the AGV body leaves the unloading waiting position, thus completing the material removal action.

[0027] Application results: The control method has a simple implementation process and has been actually used and operated on multiple project sites. Engineering tests have verified that the results of this control method are stable and reliable.

[0028] The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. A method for controlling communication between a PLC and a third-party AGV device, used for material transfer, wherein the material transfer process is divided into two situations: material moving in and moving out, and is characterized in that: It includes a PLC system and an AGV system, wherein a material moving-in communication interaction subroutine and a material moving-out communication interaction subroutine are programmed inside the PLC system and the AGV system, and the subroutine includes a strategy for determining whether to call the current communication interaction subroutine.

2. A method for controlling communication between a PLC and a third-party AGV device according to claim 1, characterized in that: The PLC system serves as a control center, responsible for processing requests from the AGV system and feeding back corresponding status information.

3. A method for controlling communication between a PLC and a third-party AGV device according to claim 1, characterized in that: The AGV system serves as an execution unit and is responsible for sending requests to the PLC system and receiving feedback from the PLC system.

4. A method for controlling communication between a PLC and a third-party AGV device according to claim 1, characterized in that: The material moving-in communication interaction subroutine in the PLC system: The PLC system needs to add 5 interactive data variables, namely move-in request MoveIn_Request, admission MoveIn_AdmissionIn, move-in completion confirmation MoveIn_FinishAffirm, material type MoveIn_Type, and material quantity MoveIn_Quantity. Among them, the data types of move-in request MoveIn_Reques, admission MoveIn_AdmissionIn, and move-in completion confirmation MoveIn_FinishAffirm are all bool type, the data type of material type MoveIn_Type is String type, and the data type of material quantity MoveIn_Quantity is Int type.

5. A method for controlling communication between a PLC and a third-party AGV device according to claim 4, characterized in that: The material moving-in communication interaction subroutine in the AGV system: The AGV system needs to add four interactive data variables, namely, request to enter MoveIn_RequestIn, move-in completion MoveIn_Finish, material type MoveIn_Type, and material quantity MoveIn_Quantity. Among them, the data types of request to enter MoveIn_RequestIn and move-in completion MoveIn_Finish are both bool type, the data type of material type MoveIn_Type is String type, and the data type of material quantity MoveIn_Quantity is Int type.

6. A method for controlling communication between a PLC and a third-party AGV device according to claim 5, characterized in that: The material moving-in communication interaction subroutine process steps are as follows: S1, PLC and AGV equipment automatically start running; S2, the detection program determines whether the workstation is short of materials and needs to be moved in. If necessary, proceed to step S3, if not, re-test; S3, entering the communication interaction subroutine; S4, PLC sends a move-in request Move In_Request; S5, AGV feedback request enters MoveIn_RequestIn; S6, PLC sends permission to enter MoveIn_AdmissionIn; S7, AGV sends MoveIn_Finish; S8, AGV sends the material type MoveIn_Type and quantity MoveIn_Quantity; S9, PLC feedback the type of material moved in MoveIn_Type and the quantity MoveIn_Quantity; S10, PLC feedback MoveIn_FinishAffim confirmation; S11, the communication interaction process ends and the next task is entered, and the cycle continues to step S2.

7. A method for controlling communication between a PLC and a third-party AGV device according to claim 1, characterized in that: The material moving-out communication interaction subroutine in the PLC system: the PLC system needs to add 5 interactive data variables, namely, move-out request MoveOut_Request, move-out admission MoveOut_AdmissionIn, move-out completion confirmation MoveOut_FinishAffirm, material type MoveOut_Type, and material quantity MoveOut_Quantity, among which, the data types of move-out request MoveOut_Request, move-out admission MoveOut_AdmissionIn, and move-out completion confirmation MoveOut_FinishAffirm are all bool type, the data type of material type MoveOut_Type is String type, and the data type of material quantity MoveOut_Quantity is Int type.

8. A method for controlling communication between a PLC and a third-party AGV device according to claim 7, characterized in that: The material moving-out communication interaction subroutine of the AGV system: The AGV system needs to add 4 interactive data variables, namely, move-out request MoveOut_RequestIn, move-out completion MoveOut_Finish, move-out material type MoveOut_Type, and quantity MoveOut_Quantity, among which, The data types of MoveOut_RequestIn and MoveOut_Finish are both bool type, the data type of MoveOut_Type is String type, and the data type of MoveOut_Quantity is Int type.

9. A method for controlling communication between a PLC and a third-party AGV device according to claim 8, characterized in that: The material removal communication interaction subroutine process steps are as follows: S1, PLC and AGV equipment automatically start running; S2, the detection program determines whether the station is full and needs to be moved out. If necessary, it goes to step S3. If not, it re-detects; S3, entering the moving-out communication interaction subroutine; S4, PLC sends a move-out request MoveOut_Request; S5, AGV feedback request enters MoveOut_RequestIn; S6, PLC sends permission to enter MoveOut_AdmissionIn; S7, PLC sends the material type MoveOut_Type and quantity MoveOut_Quantity; S8, AGV sends MoveOut Finish; S9, AGV feedback the type of material moved out MoveOut_Type, quantity MoveOut_Quantity; S10, PLC feedback MoveOut_FinishAffirm; S11, the communication interaction process ends and the next task is entered, and the cycle continues to step S2.

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