RFID-based flexible production line group control system and method

Abstract

The application discloses a flexible production line group control system and method based on RFID, wherein a group control unit is connected with a production line control PLC unit and an MES unit respectively, receives production task information of the MES unit and production line equipment information of the production line control PLC unit, and performs production scheduling based on the production information and the production line equipment information; the group control unit reads and writes RFID tag information of materials on each production line based on a production scheduling scheme and an RFID unit, simultaneously records production line equipment processing information, and completes group control of the production line. Through cooperation of the group control unit and the RFID, the application can accurately record a model, an order number and other accessory information of each workpiece, and accurately and automatically transmit the information to production equipment, so that the production equipment calls an automatic processing program and produces according to the model and other information, connects the MES unit and the production line control PLC unit, improves flexibility, digitization and intelligentization of the production line, and effectively realizes cost reduction and benefit increase in an enterprise production process.

Description

Technical Field

[0001] This invention belongs to the field of intelligent production control, specifically relating to a flexible production line group control system and method based on RFID. Background Technology

[0002] The flexible assembly line combines customized automated equipment, workbenches, and material transport lines. It has a unified information control system and material storage and transportation system, enabling the system to perform autonomous identification, autonomous control, and autonomous detection, thus achieving flexible and autonomous production.

[0003] For production operations characterized by diverse product types, small batches, and changing conditions, resource management in industrial production is a challenging issue due to the variety of resources such as workpieces, pallets, materials, and personnel, as well as their harsh environments, dispersed locations, and high mobility. When product quality issues arise, information traceability is often difficult, resulting in significant waste of time and resources.

[0004] Traditional production line control systems have limited compatibility with the number of equipment, poor equipment scheduling flexibility, low safety, and are not suitable for mixed-line production of multiple varieties and small batches of products. Moreover, production costs cannot be accurately calculated, and scientific management of workshop production equipment cannot be achieved. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a flexible production line group control system and method based on RFID. By using RFID electronic tags and RFID readers, data from multiple sources, including materials, work-in-process, execution equipment, and tooling, can be collected in real time, thereby improving production efficiency and reducing production line downtime.

[0006] By placing RFID tags on materials or tooling pallets to record relevant information such as product size, quantity, time, and personnel, production managers can keep abreast of production status and adjust production arrangements accordingly, and keep track of material flow at any time. This improves the flexibility, digitalization, and intelligence of the production line, effectively reducing costs and increasing efficiency in the enterprise's production process.

[0007] The specific technical solution for achieving the objective of this invention is as follows:

[0008] A flexible production line group control system based on RFID includes a group control unit, a production line control PLC unit, a MES unit, and an RFID unit.

[0009] The group control unit is connected to the production line control PLC unit and the MES unit respectively, receives production task information from the MES unit and production line equipment information from the production line control PLC unit, and performs production scheduling based on the production information and production line equipment information.

[0010] The group control unit reads and writes RFID tag information of materials on each production line based on the production scheduling scheme and RFID unit, and records the processing information of each production line equipment to complete the group control of the production line.

[0011] Furthermore, the group control unit includes a central control module, a data management module, a data interface module, a scheduling module, and a monitoring module;

[0012] The master control module is used to control the other modules in the group control unit;

[0013] The data management module collects product production process quality data in real time through RFID units and transmits it to each process as a completion inspection criterion. Finally, the collected data is stored in the database.

[0014] The data interface module completes data interaction between the MES unit, the production line control PLC unit, the RFID unit, and the group control unit through the data interface.

[0015] The scheduling module is used to schedule production line materials based on the production information from the MES unit.

[0016] The monitoring module monitors the material processing status of the production line by reading information from the RFID unit.

[0017] Furthermore, the RFID unit includes an RFID electronic tag and an RFID reader / writer;

[0018] The RFID reader is connected to the group control unit and is controlled by the group control unit to complete the query and reading / writing of data information in the RFID electronic tag.

[0019] The RFID electronic tags are placed on the material or tooling pallets of each production line.

[0020] Furthermore, the scheduling module, combining the production task information issued by the MES unit and the set production scheduling principles, generates a scheduling scheme based on the scheduling model, specifically as follows:

[0021] The production scheduling principle is based on either cost priority or delivery time priority.

[0022] The scheduling model is as follows:

[0023] Suppose there are n workpieces to be processed on m machines, and each workpiece has p processing steps with process constraints. Then the set of workpieces is represented as {W1, W2, ... W}. n The set of devices is represented as {M1, M2, ..., M}. m The process set is represented as {Q1, Q2, ..., Q}. p},but:

[0024]

[0025]

[0026]

[0027] g(x) = min(max|t) fi -T i |)

[0028] Where a and b are weighting factors, a+b=1, a≥0, b≥0, f(x) is the minimum maximum completion time of all parts in any production order, and h(x) is the total energy consumption cost of all parts in the same order as f(x) from the start to the end of processing.

[0029] Indicates process P ij In processing equipment M k The start time of processing on Indicates process P ij In processing equipment M k Total processing time, P ij M represents the j-th process of the i-th workpiece. k This represents the k-th processing equipment; For device M k The energy consumption cost of processing the j-th process of the i-th workpiece. To select processing equipment M k Process P ij Processing, EC k Indicates processing equipment M k Non-processing energy consumption cost; t fi Let T be the completion time of workpiece i. i Let be the delivery date of workpiece i, where 1≤i≤n, 1≤j≤p, and 1≤k≤m.

[0030] Furthermore, the constraints of the scheduling model are:

[0031] (1) The same workpiece must be processed according to its established process sequence, while different workpieces can be processed in parallel without being constrained by the process sequence;

[0032] t sij ≤t si(j+1)

[0033] Among them, t sij t is the start time of the j-th operation for the i-th workpiece. si(j+1) Let J be the start time of the (j+1)th operation for the i-th workpiece.

[0034] (2) At any given time, each processing equipment can only perform one process, and each workpiece can only be processed on one processing equipment at any given time.

[0035]

[0036] This indicates that at least one machine can process step P. ij ;

[0037]

[0038] in, For processing equipment M k The start time of the j-th process for the i-th workpiece. For processing equipment M k The processing time for completing the j-th operation of the i-th workpiece. For processing equipment M k The start time of the (j+1)th operation for the i-th workpiece;

[0039] (3) Products on temporary orders are given priority for processing in a certain process. The earliest priority for a temporary order's delivery date is set to level 1, and the latest priority is set to level n. When a temporary order is to be delivered to equipment M... k Workpiece W being machined a Encountering temporary workpiece W i At that time, workpiece W i In device M k Process P ij The end time is longer than that of workpiece W. a In device M k Process P ab The start time must be early, that is, it must satisfy:

[0040]

[0041] The group control method based on the above system includes the following steps:

[0042] Step 1: After the system starts, the group control unit reads the configuration information of the RFID units in the system and determines the status of all production lines and each processing equipment.

[0043] Step 2: Based on the production task information issued by the MES unit, the group control unit generates a scheduling plan according to the production scheduling principle and scheduling model, and sends the scheduling plan to each production line workstation based on the production line control PLC unit to complete the scheduling of production materials.

[0044] Step 3: The group control unit monitors the materials on each production line based on the scheduling scheme and RFID unit. When it is determined that the workpiece has arrived at each processing equipment on the production line, it performs the reading and writing of RFID tag information.

[0045] Step 4: After the RFID tag information reading and writing is completed and the processing step is finished, determine whether the RFID tag exists. If it exists, determine that the workpiece has passed the point and the group control system reads the tag data. If it does not exist, log the data and automatically assign a new tag.

[0046] Step 5: After the workpiece completes each processing step, the group control system determines the time and energy consumption of the workpiece at each processing equipment based on the workpiece's RFID tag information, records and uploads the workpiece's transit records at each processing equipment, and completes the control and monitoring of the entire workpiece processing process on each production line.

[0047] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0048] (1) The technical solution of the present invention can locate, track and control the workpiece / pallet in real time on the flexible production line, realize the production of multiple models of mixed production, flexible production, management of multiple models of workpieces, detection of the existence of objects during product processing, tracking of the dynamics of objects, prediction of the position of objects, and automatic recording of the production process, replacing the traditional manual recording. It can grasp the production status in time and adjust the production arrangement according to the situation, control the flow of materials at any time, centrally control and manage the production resources of the production line, collect equipment and product operating parameters in real time, perform quality analysis and monitoring of materials and finished products, and promptly alarm for production abnormalities, reduce the downtime rate of the production line, and ultimately achieve efficient operation of the production line and reliable traceability of quality information, effectively realizing cost reduction and efficiency improvement in the production process of enterprises.

[0049] (2) In the technical solution of the present invention, the combination of group control unit and RFID can accurately record the model, order number and other auxiliary information of each workpiece, and accurately and automatically transmit them to the production equipment. The production equipment can then call the automated processing program and produce according to the model and other information. The MES unit is connected to the production line control PLC unit, and the production plan queue is automatically read from the MES unit. The unique code of the workpiece is written into the RFID tag completely and without error according to the queue. The accuracy rate of RFID tag reading and writing is higher than 99.9%. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the RFID-based flexible production line group control system architecture of the present invention.

[0051] Figure 2 This is a flowchart of the steps of the RFID-based flexible production line group control method of the present invention.

[0052] Figure 3 This is a schematic diagram of the group control unit interface in an embodiment of the present invention.

[0053] Figure 4 This is a schematic diagram of the interaction interface between the group control unit and the MES unit in an embodiment of the present invention.

[0054] Figure 5 This is a schematic diagram of the interaction interface between the group control unit and the production line control PLC unit in an embodiment of the present invention.

[0055] Figure 6 This is the RFID unit information management interface in an embodiment of the present invention. Detailed Implementation

[0056] A flexible production line group control system based on RFID includes a group control unit, a production line control PLC unit, a MES unit, and an RFID unit.

[0057] The group control unit is connected to the production line control PLC unit and the MES unit respectively, receives production task information from the MES unit and production line equipment information from the production line control PLC unit, and performs production scheduling based on the production information and production line equipment information.

[0058] More specifically, the group control unit creates task orders based on the production task information issued by the MES unit and synchronizes task order information, including task order code, production plan code, workpiece / pallet unique identifier code, task order creation time, etc.

[0059] The group control unit reads and writes RFID tag information of materials on each production line based on the production scheduling scheme and RFID unit, and records the processing information of each production line equipment to complete the group control of the production line.

[0060] Furthermore, the group control unit includes a central control module, a data management module, a data interface module, a scheduling module, and a monitoring module;

[0061] The master control module is used to control the other modules in the group control unit;

[0062] The data management module collects product production process quality data in real time through RFID units and transmits it to each process as a completion inspection criterion. Finally, the collected data is stored in the database.

[0063] The data interface module completes data interaction between the MES unit, the production line control PLC unit, the RFID unit, and the group control unit through the data interface.

[0064] The scheduling module is used to schedule production line materials based on the production information from the MES unit.

[0065] The monitoring module monitors the material processing status of the production line by reading information from the RFID unit.

[0066] Furthermore, the RFID unit includes an RFID electronic tag and an RFID reader / writer;

[0067] The RFID reader is connected to the group control unit and is controlled by the group control unit to complete the query and reading / writing of data information in the RFID electronic tag.

[0068] The RFID electronic tags are placed on the material or tooling pallets of each production line.

[0069] Furthermore, the scheduling module, combining the production task information issued by the MES unit and the set production scheduling principles, generates a scheduling scheme based on the scheduling model, specifically as follows:

[0070] The production scheduling principle is based on either cost priority or delivery time priority.

[0071] The scheduling model is as follows:

[0072] Suppose there are n workpieces to be processed on m machines, and each workpiece has p processing steps with process constraints. Then the set of workpieces is represented as {W1, W2, ... W}. n The set of devices is represented as {M1, M2, ... M}. m The process set is represented as {Q1, Q2, ... Q}. p For multi-objective optimization problems involving different units, a normalization method is used to ensure the scientific validity of the method.

[0073]

[0074]

[0075]

[0076] g(x) = min(max|t) fi -T i |)

[0077] Among them, a model was constructed based on the principle of prioritizing cost, and the normalized objective function after weighted processing was minC. max = f(x)×a+h(x)×b, where a and b are weighting factors, a+b=1, a≥0, b≥0, f(x) is the minimum maximum completion time for all parts in any production order, and h(x) is the total energy consumption cost of all parts in the same order as f(x) from the start to the end of processing.

[0078] Indicates process P ij In processing equipment M k The start time of processing on Indicates process P ij In processing equipment M k Total processing time, P ij M represents the j-th process of the i-th workpiece. k This represents the k-th processing equipment; For device M k The energy consumption cost of processing the j-th process of the i-th workpiece. To select processing equipment M k Process P ij Processing, EC k Indicates processing equipment M k Non-processing energy consumption cost; t fi Let T be the completion time of workpiece i. i Let be the delivery date of workpiece i, where 1≤i≤n, 1≤j≤p, and 1≤k≤m.

[0079] Furthermore, the constraints of the scheduling model are:

[0080] (1) The same workpiece must be processed according to its established process sequence, while different workpieces can be processed in parallel without being constrained by the process sequence;

[0081] t sij ≤t si(j+1)

[0082] Among them, t sij t is the start time of the j-th operation for the i-th workpiece. si(j+1) Let J be the start time of the (j+1)th operation for the i-th workpiece.

[0083] (2) At any given time, each processing equipment can only perform one process, and each workpiece being processed can only be processed on one processing equipment at any given time.

[0084]

[0085] This indicates that at least one machine can process step P. ij ;

[0086]

[0087] in, For processing equipment M k The start time of the j-th process for the i-th workpiece. For processing equipment M kThe processing time for completing the j-th operation of the i-th workpiece. For processing equipment M k The start time of the (j+1)th operation for the i-th workpiece;

[0088] (3) Products on temporary orders are given priority for processing in a certain process. The earliest priority for a temporary order's delivery date is set to level 1, and the latest priority is set to level n. When a temporary order is to be delivered to equipment M... k Workpiece W being machined a Encountering temporary workpiece W i At that time, workpiece W i In device M k Process P ij The end time is longer than that of workpiece W. a In device M k Process P ab The start time must be early, that is, it must satisfy:

[0089]

[0090] The group control method based on the above system includes the following steps:

[0091] Step 1: After the system starts, the group control unit reads the configuration information of the RFID units in the system and determines the status of all production lines and each processing equipment.

[0092] Step 2: Based on the production task information issued by the MES unit, the group control unit generates a scheduling plan according to production scheduling principles and the scheduling model. This plan is then sent to each production line workstation via the production line control PLC unit to complete the scheduling of production materials. Specifically:

[0093] More specifically, the group control unit creates task orders based on the production task information issued by the MES unit and synchronizes task order information, including task order code, production plan code, unique identifier code for workpiece / pallet, and task order creation time.

[0094] The production scheduling principle is based on either cost priority or delivery time priority.

[0095] The scheduling model is as follows:

[0096] Suppose there are n workpieces to be processed on m machines, and each workpiece has p processing steps with process constraints. Then the set of workpieces is represented as {W1, W2, ... W}. n The set of devices is represented as {M1, M2, ... M}. m The process set is represented as {Q1, Q2, ... Q}. pFor multi-objective optimization problems involving different units, a normalization method is used to ensure the scientific validity of the method.

[0097]

[0098]

[0099]

[0100] g(x) = min(max|t) fi -T i |)

[0101] Among them, a model was constructed based on the principle of prioritizing cost, and the normalized objective function after weighted processing was minC. max = f(x)×a+h(x)×b, where a and b are weighting factors, a+b=1, a≥0, b≥0, f(x) is the minimum maximum completion time for all parts in any production order, and h(x) is the total energy consumption cost of all parts in the same order as f(x) from the start to the end of processing.

[0102] Indicates process P ij In processing equipment M k The start time of processing on Indicates process P ij In processing equipment M k Total processing time, P ij M represents the j-th process of the i-th workpiece. k This represents the k-th processing equipment; For device M k The energy consumption cost of processing the j-th process of the i-th workpiece. To select processing equipment M k Process P ij Processing, EC k Indicates processing equipment M k Non-processing energy consumption cost; t fi Let T be the completion time of workpiece i. i Let be the delivery date of workpiece i, where 1≤i≤n, 1≤j≤p, and 1≤k≤m.

[0103] The constraints of the scheduling model are:

[0104] (1) The same workpiece must be processed according to its established process sequence, while different workpieces can be processed in parallel without being constrained by the process sequence;

[0105] t sij ≤t si(j+1)

[0106] Among them, t sij t is the start time of the j-th operation for the i-th workpiece. si(j+1) Let J be the start time of the (j+1)th operation for the i-th workpiece.

[0107] (2) At any given time, each processing equipment can only perform one process, and each workpiece being processed can only be processed on one processing equipment at any given time.

[0108]

[0109] This indicates that at least one machine can process step P. ij ;

[0110]

[0111] in, For processing equipment M k The start time of the j-th process for the i-th workpiece. For processing equipment M k The processing time for completing the j-th operation of the i-th workpiece. For processing equipment M k The start time of the (j+1)th operation for the i-th workpiece;

[0112] (3) Products on temporary orders are given priority for processing in a certain process. The earliest delivery date for temporary orders is set to priority level 1, and the latest delivery date is set to priority level n. When the product is to be processed on equipment M k Workpiece W being machined a Encountering temporary workpiece W i At that time, workpiece W i In device M k Process P ij The end time is longer than that of workpiece W. a In device M k Process P ab The start time must be early, that is, it must satisfy:

[0113]

[0114] Step 3: The group control unit monitors the materials on each production line based on the scheduling scheme and RFID unit. When it is determined that the workpiece has arrived at each processing equipment on the production line, it performs the reading and writing of RFID tag information.

[0115] Step 4: After the RFID tag information reading and writing is completed and the processing step is finished, determine whether the RFID tag exists. If it exists, determine that the workpiece has passed the point and the group control system reads the tag data. If it does not exist, log the data and automatically assign a new tag.

[0116] Step 5: After the workpiece completes each processing step, the group control system determines the time and energy consumption of the workpiece at each processing equipment based on the workpiece's RFID tag information, records and uploads the workpiece's transit records at each processing equipment, and completes the control and monitoring of the entire workpiece processing process on each production line.

[0117] The present invention will be further described below with reference to the embodiments.

[0118] Example

[0119] A flexible production line group control system based on RFID includes a group control unit, a production line control PLC unit, a MES unit, and an RFID unit.

[0120] The group control unit is connected to the production line control PLC unit and the MES unit respectively, receives production task information from the MES unit and production line equipment information from the production line control PLC unit, and performs production scheduling based on the production information and production line equipment information.

[0121] More specifically, the group control unit creates task orders based on the production task information issued by the MES unit and synchronizes task order information, including task order code, production plan code, workpiece / pallet unique identifier code, task order creation time, etc.

[0122] The group control unit reads and writes RFID tag information of materials on each production line based on the production scheduling scheme and RFID unit, and records the processing information of each production line equipment to complete the group control of the production line.

[0123] In this embodiment, the group control unit is applied on a flexible automated production line and interacts with the MES unit and the production line control PLC unit through a production line switch.

[0124] More specifically, the group control system in this embodiment is used on an automated CNC machine tool production line. It connects to the production line's control network and operates within the same network as the server, industrial computer, and a certain number of RFID readers. All RFID readers are connected to the group control unit. Each reader controls UHF tags at a distance of approximately 50cm. At most, only one UHF RFID tag will exist within the reading range of each reader. If more than one tag appears, the reader automatically filters out tags that are too far away based on internal query conditions, recording and writing the tag with the strongest signal as the valid tag. Figure 1 As shown;

[0125] Furthermore, the group control unit includes a central control module, a data management module, a data interface module, a scheduling module, and a monitoring module;

[0126] The master control module is used to control the other modules in the group control unit;

[0127] The data management module collects product production process quality data in real time through RFID units and transmits it to each process as a completion inspection criterion. Finally, the collected data is stored in the database.

[0128] The data interface module completes data interaction between the MES unit, the production line control PLC unit, the RFID unit, and the group control unit through the data interface.

[0129] The scheduling module is used to schedule production line materials based on the production information from the MES unit.

[0130] The monitoring module monitors the material processing status of the production line by reading information from the RFID unit.

[0131] Furthermore, the RFID unit includes an RFID electronic tag and an RFID reader / writer;

[0132] The RFID reader is connected to the group control unit and is controlled by the group control unit to complete the query and reading / writing of data information in the RFID electronic tag.

[0133] The RFID electronic tags are placed on the material or tooling pallets of each production line.

[0134] In this embodiment, the RFID unit is connected to the group control unit. Each RFID reader controls RFID UHF electronic tags at a distance of 50cm. At most, there will be only one RFID UHF tag within the reading and writing range of each reader. If more than one tag appears, the reader will automatically filter out tags that are too far away according to the internal query conditions and record and write the tag with the stronger signal as a valid tag.

[0135] RFID tags can be metal tags, document management tags, or other customized tags, and RFID readers can be mobile handheld readers or fixed access control readers.

[0136] Furthermore, the scheduling module, combining the production task information issued by the MES unit and the set production scheduling principles, generates a scheduling scheme based on the scheduling model, specifically as follows:

[0137] The production scheduling principle is based on either cost priority or delivery time priority.

[0138] The scheduling model is as follows:

[0139] Suppose there are n workpieces to be processed on m machines, and each workpiece has p processing steps with process constraints. Then the set of workpieces is represented as {W1, W2, ... W}. n The set of devices is represented as {M1, M2, ... M}. m The process set is represented as {Q1, Q2, ... Q}. p For multi-objective optimization problems involving different units, a normalization method is used to ensure the scientific validity of the method.

[0140]

[0141]

[0142]

[0143] g(x) = min(max|t) fi -T i |)

[0144] Among them, a model was constructed based on the principle of prioritizing cost, and the normalized objective function after weighted processing was minC. max = f(x)×a+h(x)×b, where a and b are weighting factors, a+b=1, a≥0, b≥0, f(x) is the minimum maximum completion time for all parts in any production order, and h(x) is the total energy consumption cost of all parts in the same order as f(x) from the start to the end of processing.

[0145] Indicates process P ij In processing equipment M k The start time of processing on Indicates process P ij The total processing time P on processing equipment Mk ij M represents the j-th process of the i-th workpiece. k This represents the k-th processing equipment; For device M k The energy consumption cost of processing the j-th process of the i-th workpiece. To select processing equipment M k Process P ij Processing, EC k Indicates processing equipment M k Non-processing energy consumption cost; t fi Let T be the completion time of workpiece i. i Let be the delivery date of workpiece i, where 1≤i≤n, 1≤j≤p, and 1≤k≤m.

[0146] Furthermore, the constraints of the scheduling model are:

[0147] (1) The same workpiece must be processed according to its established process sequence, while different workpieces can be processed in parallel without being constrained by the process sequence;

[0148] t sij ≤t si(j+1)

[0149] Among them, t sij t is the start time of the j-th operation for the i-th workpiece. si(j+1) Let J be the start time of the (j+1)th operation for the i-th workpiece.

[0150] (2) At any given time, each processing equipment can only perform one process, and each workpiece being processed can only be processed on one processing equipment at any given time.

[0151]

[0152] This indicates that at least one machine can process step P. ij ;

[0153]

[0154] in, For processing equipment M k The start time of the j-th process for the i-th workpiece. For processing equipment M k The processing time for completing the j-th operation of the i-th workpiece. For processing equipment M k The start time of the (j+1)th operation for the i-th workpiece;

[0155] (3) Products on temporary orders are given priority for processing in a certain process. The earliest delivery date for temporary orders is set to priority level 1, and the latest delivery date is set to priority level n. When the product is to be processed on equipment M k Workpiece W being machined a Encountering temporary workpiece W i At that time, workpiece W i In device M k Process P ij The end time is longer than that of workpiece W. a In device M k Process P ab The start time must be early, that is, it must satisfy:

[0156]

[0157] In this embodiment, the format of the read command and response data returned between the group control unit and the RFID reader is defined as follows:

[0158] Group control system command data block:

[0159] Len: The length of the command data block, excluding Len itself. The data block length equals 4 plus the length of Data[]. Len has a maximum allowed value of 96 and a minimum value of 4, with a length of 1 byte.

[0160] Adr: Reader address; Address range: 0x00~0xFE, 0xFF is the broadcast address. The reader only responds to commands with the same address as itself and commands with an address of 0xFF. The reader is manufactured with an address of 0x00 and a byte length of 1.

[0161] Cmd: Command code, 1 byte in length;

[0162] Data[]: Parameter field, which may not exist in the actual command, and its length in bytes is indefinite;

[0163] LSB-CRC16: CRC16 low byte, CRC16 is the CRC16 value from Len to Data[], with a byte length of 1;

[0164] MSB-CRC16: CRC16 high byte, byte length is 1;

[0165] Reader response data block:

[0166] Len: The length of the response data block, excluding Len itself. That is, the length of the data block is equal to 5 plus the length of Data[], and the length in bytes is 1.

[0167] Adr: Reader address, 1 byte in length;

[0168] reCmd: Indicates which command the response data block is a response to. If it is a response to an unrecognized command, reCmd is 0x00 and the length is 1 byte.

[0169] Status: Command execution result status value, with a length of 1 byte;

[0170] Data[]: Data field, may not exist, and its length in bytes is variable;

[0171] LSB-CRC16: CRC16 low byte, CRC16 is the CRC16 value from Len to Data[], with a byte length of 1;

[0172] MSB-CRC16: CRC16 high byte, byte length is 1;

[0173] Combination Figure 2 The group control method based on the above system includes the following steps:

[0174] Step 1: After the system starts, the group control unit reads the configuration information of the RFID units in the system and determines the status of all production lines and each processing equipment.

[0175] The configuration information includes basic information such as the RFID reader's IP address, port, frequency, and identifier.

[0176] Step 2: Based on the production task information issued by the MES unit, the group control unit generates a scheduling plan according to production scheduling principles and the scheduling model. This plan is then sent to each production line workstation via the production line control PLC unit to complete the scheduling of production materials. Specifically:

[0177] More specifically, the group control unit creates task orders based on the production task information issued by the MES unit and synchronizes task order information, including task order code, production plan code, unique identifier code for workpiece / pallet, and task order creation time.

[0178] The production scheduling principle is based on either cost priority or delivery time priority.

[0179] The scheduling model is as follows:

[0180] Suppose there are n workpieces to be processed on m machines, and each workpiece has p processing steps with process constraints. Then the set of workpieces is represented as {W1, W2, ... W}. n The set of devices is represented as {M1, M2, ..., M}. m The process set is represented as {Q1, Q2, ..., Q}. p For multi-objective optimization problems involving different units, a normalization method is used to ensure the scientific validity of the method.

[0181]

[0182]

[0183]

[0184] g(x) = min(max|t) fi -T i |)

[0185] Among them, a model was constructed based on the principle of prioritizing cost, and the normalized objective function after weighted processing was minC. max= f(x)×a+h(x)×b, where a and b are weighting factors, a+b=1, a≥0, b≥0, f(x) is the minimum maximum completion time for all parts in any production order, and h(x) is the total energy consumption cost of all parts in the same order as f(x) from the start to the end of processing.

[0186] Indicates process P ij In processing equipment M k The start time of processing on Indicates process P ij In processing equipment M k Total processing time, P ij M represents the j-th process of the i-th workpiece. k This represents the k-th processing equipment; For device M k The energy consumption cost of processing the j-th process of the i-th workpiece. To select processing equipment M k Process P ij Processing, EC k Indicates processing equipment M k Non-processing energy consumption cost; t fi Let T be the completion time of workpiece i. i Let be the delivery date of workpiece i, where 1≤i≤n, 1≤j≤p, and 1≤k≤m.

[0187] The constraints of the scheduling model are:

[0188] (1) The same workpiece must be processed according to its established process sequence, while different workpieces can be processed in parallel without being constrained by the process sequence;

[0189] t sij ≤t si(j+1)

[0190] Among them, t sij t is the start time of the j-th operation for the i-th workpiece. si(j+1) Let J be the start time of the (j+1)th operation for the i-th workpiece.

[0191] (2) At any given time, each processing equipment can only perform one process, and each workpiece being processed can only be processed on one processing equipment at any given time.

[0192]

[0193] This indicates that at least one machine can process step P. ij ;

[0194]

[0195] in, For processing equipment M k The start time of the j-th process for the i-th workpiece. For processing equipment M k The processing time for completing the j-th operation of the i-th workpiece. For processing equipment M k The start time of the (j+1)th operation for the i-th workpiece;

[0196] (3) Products on temporary orders are given priority for processing in a certain process. The earliest delivery date for temporary orders is set to priority level 1, and the latest delivery date is set to priority level n. When the product is to be processed on equipment M k Workpiece W being machined a Encountering temporary workpiece W i At that time, workpiece W i In device M k Process P ij The end time is longer than that of workpiece W. a In device M k Process P ab The start time must be early, that is, it must satisfy:

[0197]

[0198] Step 3: The group control unit monitors the materials on each production line based on the scheduling scheme and RFID unit. When it is determined that the workpiece has arrived at each processing equipment on the production line, it performs the reading and writing of RFID tag information.

[0199] Step 4: After the RFID tag information reading and writing is completed and the processing step is finished, determine whether the RFID tag exists. If it exists, determine that the workpiece has passed the point and the group control system reads the tag data. If it does not exist, log the data and automatically assign a new tag.

[0200] Step 5: After the workpiece completes each processing step, the group control system determines the time and energy consumption of the workpiece at each processing equipment based on the workpiece's RFID tag information, records and uploads the workpiece's transit records at each processing equipment, and completes the control and monitoring of the entire workpiece processing process on each production line.

[0201] The wireless RFID group control system connects to the wireless RFID reader / writer via RS232 / RS485 serial port or RJ45 Ethernet port. The reader / writer performs operations such as reading, writing, querying, and scanning RFID tags. Depending on the site conditions and the efficiency of high-frequency or ultra-high-frequency operation, an antenna can be added to increase the tag reading success rate. Figure 3 As shown;

[0202] In this embodiment, the interaction interface between the group control unit and the MES unit is as follows: Figure 4 As shown, the interaction interface between the group control unit and the production line control PLC unit is as follows: Figure 5 As shown, the information management interface of the RFID unit in this embodiment is as follows: Figure 6 As shown.

[0203] The technical solution of this invention, through the cooperation of a group control unit and RFID, can accurately record the model, order number and other ancillary information of each workpiece, and accurately and automatically transmit it to the production equipment. The production equipment then calls the automated processing program and starts production based on the model and other information. It connects the MES unit and the production line control PLC unit, automatically reads the production plan queue from the MES unit, and writes the unique code of the workpiece into the RFID tag completely and accurately according to the queue. The accuracy rate of RFID tag reading and writing is higher than 99.9%, which improves the flexibility, digitalization and intelligence of the production line, and effectively realizes cost reduction and efficiency improvement in the enterprise's production process.

[0204] The above embodiments illustrate and describe the basic principles and main features of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A flexible production line group control system based on RFID, characterized in that, This includes a group control unit, a production line control PLC unit, a MES unit, and an RFID unit; The group control unit is connected to the production line control PLC unit and the MES unit respectively, receives production task information from the MES unit and production line equipment information from the production line control PLC unit, and performs production scheduling based on the production information and production line equipment information. The group control unit reads and writes RFID tag information of materials on each production line based on the production scheduling scheme and RFID unit, and records the processing information of each production line equipment to complete the group control of the production line. The group control unit includes a central control module, a data management module, a data interface module, a scheduling module, and a monitoring module; The scheduling module, combining the production task information issued by the MES unit and the established production scheduling principles, generates a scheduling scheme based on the scheduling model, specifically as follows: The production scheduling principle is based on either cost priority or delivery time priority. The scheduling model is as follows: Suppose there are n workpieces to be processed on m machines, and each workpiece has p processing steps with process constraints. Then the set of workpieces is represented as {W1, W2, ..., Wn}. n The set of devices is represented as {M1, M2, ..., M}. m The process set is represented as {Q1, Q2, ..., Q}. p },but: ； ； + }； ； Where a and b are weighting factors, a + b = 1, a ≥ 0, b ≥ 0. For any production order, the minimum maximum completion time for all parts is given. To and The total energy cost of the equipment used for all parts in the same order from the start to the end of processing; Indicates process P ij In processing equipment M k The start time of processing on Indicates process P ij In processing equipment M k Total processing time, P ij M represents the j-th process of the i-th workpiece. k This represents the k-th processing equipment; For device M k The energy consumption cost of processing the j-th process of the i-th workpiece. To select processing equipment M k Process P ij Processing, Indicates processing equipment M k Non-processing energy consumption costs; Let T be the completion time of workpiece i. i Let be the delivery date of workpiece i, where 1≤i≤n, 1≤j≤p, and 1≤k≤m.

2. The RFID-based flexible production line group control system according to claim 1, characterized in that, The master control module is used to control the other modules in the group control unit; The data management module collects product production process quality data in real time through RFID units and transmits it to each process as a completion inspection criterion. Finally, the collected data is stored in the database. The data interface module completes data interaction between the MES unit, the production line control PLC unit, the RFID unit, and the group control unit through the data interface. The scheduling module is used to schedule production line materials based on the production information from the MES unit. The monitoring module monitors the material processing status of the production line by reading information from the RFID unit.

3. The RFID-based flexible production line group control system according to claim 1, characterized in that, The RFID unit includes an RFID electronic tag and an RFID reader / writer; The RFID reader is connected to the group control unit and is controlled by the group control unit to complete the query and reading / writing of data information in the RFID electronic tag. The RFID electronic tags are placed on the material or tooling pallets of each production line.

4. The RFID-based flexible production line group control system according to claim 1, characterized in that, The constraints of the scheduling model are: (1) The same workpiece must be processed according to its established process sequence, while different workpieces can be processed in parallel without being constrained by the process sequence; ； in, Let be the start time of the j-th operation for the i-th workpiece. Let J be the start time of the (j+1)th operation for the i-th workpiece. (2) At any given time, each processing equipment can only perform one process, and each workpiece can only be processed on one processing equipment at any given time. ； This indicates that at least one machine can process step P. ij ; + ≤ ； in, For processing equipment M k The start time of the j-th process for the i-th workpiece. For processing equipment M k The processing time for completing the j-th operation of the i-th workpiece. For processing equipment M k The start time of the (j+1)th operation for the i-th workpiece; (3) Products on temporary orders are given priority in a certain process. The earliest delivery date for temporary orders is set to priority level 1, and the latest delivery date is set to priority level n. When the product is to be delivered to equipment M k Workpiece W being machined a Encountering temporary workpiece W i At that time, workpiece W i In device M k Process P ij The end time is longer than the workpiece W a In device M k Process P ab The start time must be early, that is, it must satisfy: + ≤ 。 5. A flexible production line group control method based on RFID, based on any one of claims 1-4, characterized in that, Includes the following steps: Step 1: After the system starts, the group control unit reads the configuration information of the RFID units in the system and determines the status of all production lines and each processing equipment. Step 2: Based on the production task information issued by the MES unit, the group control unit generates a scheduling plan according to the production scheduling principle and scheduling model, and sends the scheduling plan to each production line workstation based on the production line control PLC unit to complete the scheduling of production materials. Step 3: The group control unit monitors the materials on each production line based on the scheduling scheme and RFID unit. When it is determined that the workpiece has arrived at each processing equipment on the production line, it performs the reading and writing of RFID tag information. Step 4: After the RFID tag information reading and writing is completed and the processing step is finished, determine whether the RFID tag exists. If it exists, determine that the workpiece has passed the point and the group control system reads the tag data. If it does not exist, log the data and automatically assign a new tag. Step 5: After the workpiece completes each processing step, the group control system determines the time and energy consumption of the workpiece at each processing equipment based on the workpiece's RFID tag information, records and uploads the workpiece's transit records at each processing equipment, and completes the control and monitoring of the entire workpiece processing process on each production line.

6. The RFID-based flexible production line group control method according to claim 5, characterized in that, Step 2, which generates a scheduling scheme based on production scheduling principles and a scheduling model, specifically involves: The production scheduling principle is based on either cost priority or delivery time priority. The scheduling model is as follows: Suppose there are n workpieces to be processed on m machines, and each workpiece has p processing steps with process constraints. Then the set of workpieces is represented as {W1, W2, ..., Wn}. n The set of devices is represented as {M1, M2, ..., M}. m The process set is represented as {Q1, Q2, ..., Q}. p },but: ； ； + }； ； Where a and b are weighting factors, a + b = 1, a ≥ 0, b ≥ 0. For any production order, the minimum maximum completion time for all parts is given. To and The total energy cost of the equipment used for all parts in the same order from the start to the end of processing; Indicates process P ij In processing equipment M k The start time of processing on Indicates process P ij In processing equipment M k Total processing time, P ij M represents the j-th process of the i-th workpiece. k This represents the k-th processing equipment; For device M k The energy consumption cost of processing the j-th process of the i-th workpiece. To select processing equipment M k Process P ij Processing, Indicates processing equipment M k Non-processing energy consumption costs; Let T be the completion time of workpiece i. i Let be the delivery date of workpiece i, where 1≤i≤n, 1≤j≤p, and 1≤k≤m.

7. The RFID-based flexible production line group control system according to claim 6, characterized in that, The constraints of the scheduling model are: (1) The same workpiece must be processed according to its established process sequence, while different workpieces can be processed in parallel without being constrained by the process sequence; ； in, Let be the start time of the j-th operation for the i-th workpiece. Let J be the start time of the (j+1)th operation for the i-th workpiece. (2) At any given time, each processing equipment can only perform one process, and each workpiece can only be processed on one processing equipment at any given time; ； This indicates that at least one machine can process step P. ij ; + ≤ ； in, For processing equipment M k The start time of the j-th process for the i-th workpiece. For processing equipment M k The processing time for completing the j-th operation of the i-th workpiece. For processing equipment M k The start time of the (j+1)th operation for the i-th workpiece; (3) Products on temporary orders are given priority in a certain process. The earliest delivery date for temporary orders is set to priority level 1, and the latest delivery date is set to priority level n. When the product is to be delivered to equipment M k Workpiece W being machined a Encountering temporary workpiece W i At that time, workpiece W i In device M k Process P ij The end time is longer than the workpiece W a In device M k Process P ab The start time must be early, that is, it must satisfy: + ≤ 。

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