A fast evaluation method for group scheduling in a blocked flow shop

Abstract

The invention discloses a method for rapid evaluation of group scheduling of a blocked flow shop, which relates to the technical field of workshop scheduling. Taking a distributed blocked flow shop with a start-up time as an example, according to the characteristics of the blocked scheduling problem, a hierarchical inter-group and intra-group rapid evaluation method is constructed; comprising: step 1: calculating the start time, completion time, and departure time of the workpieces in the group on the machine; step 2: calculating the hierarchy of the workpieces in the group; step 3: updating the hierarchy of the workpieces in the group and calculating the offset; step 4: obtaining the maximum completion time; wherein,,,. Aiming at the group scheduling problem of a blocked flow shop, the invention proposes a method for rapid evaluation of the maximum completion time target value, which effectively shortens the calculation time, avoids repeated evaluation, reduces the calculation cost, and significantly improves the scheduling efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of workshop scheduling, in particular to a fast evaluation method for group scheduling of a blocked flow workshop. Background Art

[0002] The cell manufacturing system has been widely used in actual production, and its efficiency depends largely on grouping products that require similar processes to reduce the time required for process conversion. A typical example is the production of printed circuit boards (PCBs). The production line of PCBs usually involves multiple process steps such as design and layout, design printing on copper, etching, drilling, electroplating, coating protective film, screen printing, surface treatment, welding, etc. Due to the limited buffer capacity between adjacent machines, PCBs cannot usually be stored offline, which easily causes blocking problems during the production process. In this environment, production efficiency is greatly affected. Different PCB products are usually divided into different groups according to factors such as their design, size, component density or final application. The processing order of different PCB groups has a significant impact on production efficiency, and a certain amount of setup time (such as adjusting machines or tools) is usually required when switching groups. Reasonable scheduling and arrangement can reduce the setup cost between groups, thereby improving production efficiency and reducing delivery delays.

[0003] In the problem of group scheduling in a blocked flow shop, current research generally relies on a neighborhood search strategy based on insertion operations to seek high-quality scheduling sequences. However, this method has a significant drawback: the target value needs to be calculated frequently after the insertion operation, which greatly increases the computational burden and prolongs the optimization time, thus limiting the full play of the scheduling optimization effect. This problem may trigger a chain reaction, including unreasonable scheduling sequences, increased idle time of production lines, extended production cycles, and reduced production efficiency. At the same time, resource utilization may become insufficient or wasteful, leading to increased production costs, and may even affect product quality due to fluctuations in process processing accuracy. However, fast evaluation methods designed for blocking characteristics are still relatively scarce in existing research, making the time complexity of solving the target value remain high. Therefore, it is urgent to propose an effective solution to significantly reduce the computational overhead. This practical problem is not only of theoretical value, but also of important practical significance. Summary of the invention

[0004] In order to better solve the problem of fast calculation of target value of distributed blocking flow shop group scheduling with start-up time, an effective fast evaluation method is proposed, namely a fast evaluation method for blocking flow shop group scheduling. According to the characteristics of blocking, the fast evaluation method based on insertion neighborhood is divided into inter-group insertion acceleration criterion and intra-group insertion acceleration criterion.

[0005] The present invention provides a method for rapid evaluation of group scheduling of a blocked flow shop, wherein the first method comprises the following steps:

[0006] Step 1: Calculate the groups Artifacts in In the machine Start time on , Completion time , Leave time ;

[0007] Step 2: Calculate the group time using the start time, completion time, and departure time. Artifacts in Level ;

[0008] Step 3: The layer changes due to the insertion of the workpiece; the insertion is divided into an inter-group insertion acceleration criterion and an intra-group insertion acceleration criterion;

[0009] Based on the changes in the hierarchy, update the group Artifacts in Level And calculate the offset ;

[0010] If the acceleration criterion is inserted between groups, the specific update method is as follows:

[0011] Step 3.1: Set variables , if the group Insert at position q, , calculate the inserted group Start time , Completion time , Leave time ;

[0012] Step 3.2: Update The hierarchy of all artifacts at and after the location ; If all workpiece levels remain unchanged, calculate the offset ; According to the offset , fast calculation The departure time of each group after the location ; Recalculate the maximum completion time , that is, ;

[0013] Step 3.3: Order , ;

[0014] Step 4: Repeat steps 3.1, 3.2, and 3.3 to try all possible insertion positions in turn;

[0015] in, , , .

[0016] Further, in step 3.1, the calculation is inserted into the rear group Start time , Completion time , Leave time The calculation formula is as follows:

[0017]

[0018]

[0019]

[0020] Furthermore, in step 3.2, the calculated offset and The calculation formula for the departure time of each group after the position is as follows:

[0021]

[0022]

[0023] in, Indicates inserting the previous group Artifacts in In the machine The start time on Indicates that starting from the current group, all subsequent group levels remain unchanged.

[0024] Furthermore, the present invention also provides a method for fast evaluation of group scheduling of a blocked flow shop. The second method, based on steps 1-2 of the first method, further includes the following steps: the insertion is replaced by an acceleration criterion for inserting within the group, and the specific updating method is as follows:

[0025] Group middle, Workpieces have been scheduled, of which is the number of all workpieces in the group, >0; the workpiece Insert to Group In order to minimize the maximum completion time, >0;

[0026] Step 3.1: Calculate the group Artifacts in In the machine Start time on , Completion time , Leave time ;

[0027] Step 3.2: Define the hierarchy For Group Artifacts in In the machine Start time and machines Start time 1 The difference between the two is used to calculate the level of each artifact;

[0028] Step 3.3: If the workpiece Insert into Location, , calculate the inserted group Start time , Completion time , Leave time ;

[0029] Step 3.4: Update The hierarchy of all artifacts at and after the location ; If all workpiece levels remain unchanged, calculate the offset ; According to the offset , fast calculation The departure time of each group after the location ; Recalculate the maximum completion time , that is ;

[0030] Step 3.5: Order , ;

[0031] Step 4: Repeat steps 3.1, 3.2, 3.3, 3.4, and 3.5 to try all possible insertion positions in turn;

[0032] in, , , .

[0033] Further, in step 1 of the first and second methods, the calculation group Artifacts in In the machine Start time on , Completion time , Leave time The calculation formulas are as follows:

[0034]

[0035]

[0036]

[0037] in, Representation Group and Group In the machine Preparation time, Representation Group Artifacts in In the machine The processing time on Representation Group The number of workpieces in >0.

[0038] Furthermore, the calculation method of the level in step 2 of the first and second methods is specifically as follows:

[0039] Defining Hierarchy For Group Artifacts in In the machine Start time and machines Start time 1 The difference between the two is used to calculate the level of each artifact.

[0040] Furthermore, the calculation group Artifacts in Level The calculation formula is as follows:

[0041] ;

[0042] .

[0043] Furthermore, in step 3.3, the inserted workpiece is calculated Start time after , Completion time , Leave time , the calculation formula is as follows:

[0044] ;

[0045] ;

[0046]

[0047]

[0048] Furthermore, in step 3.4, the calculated offset and The departure time of each group after the location The calculation formula is as follows:

[0049]

[0050] .

[0051] The present invention provides a rapid evaluation method for group scheduling of flow workshops, which has the following technical effects:

[0052] Method level:

[0053] (1) The present invention innovatively introduces the concept of hierarchy and designs the acceleration criteria for inter-group insertion and intra-group insertion according to the characteristics of the blocked flow shop. Compared with the traditional rapid evaluation method, the present invention effectively reduces the amount of calculation and significantly shortens the calculation time by dynamically adjusting the hierarchical structure of the group, thereby significantly improving the overall calculation efficiency.

[0054] (2) By updating the hierarchical structure after the workpiece is inserted in real time and calculating the offset immediately, the target value can be quickly obtained when the maximum completion time needs to be calculated. In this way, not only the target value solution process is optimized, but also repeated calculations are avoided, the solution efficiency is improved, and the target value calculation is made more efficient and accurate.

[0055] Application level:

[0056] (1) The present invention introduces the concept of hierarchy and acceleration criteria, significantly reduces redundant steps, reduces the complexity of computational time, quickly evaluates and optimizes scheduling schemes, and improves computational efficiency and performance.

[0057] (2) Through level updating and offset calculation, the present invention performs more iterative optimizations within the same optimization time, improves the accuracy of the scheduling scheme and dynamically adjusts it to avoid calculation errors.

[0058] (3) The scheduling method of the present invention is flexible and supports large-scale workshop scheduling. It can efficiently respond to dynamic changes in the production environment, help enterprises optimize resource allocation, and improve production efficiency.

[0059] (4) Accurate scheduling and optimization can reduce idle time of resources, improve production line stability, reduce overproduction and waiting, and reduce production costs.

[0060] (5) The present invention has strong scalability, can adapt to the needs of intelligent production, enhance the competitiveness of enterprises, and promote the transformation of more efficient and flexible production models.

[0061] Therefore, the present invention provides a method for rapid evaluation of group scheduling of a blocked flow shop, a method for rapid evaluation of group scheduling based on hierarchy, taking a distributed blocked flow shop with a start-up time as an example, introducing the concept of hierarchy, improving the traditional calculation method, reducing the time for target value calculation or evaluation, and improving the efficiency of workshop scheduling. In addition, the present invention can well solve the calculation process of the target value in the blocking problem, and can provide a good solution for rapid calculation of the target value for group scheduling of a blocked flow shop. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 Schematic diagram of distributed blocking flow shop group scheduling with start-up time of the present invention;

[0063] Figure 2 The confidence interval comparison diagram of the present invention;

[0064] Figure 3 Comparison of the average number of iterations between the method of the present invention and the comparative method. DETAILED DESCRIPTION

[0065] Embodiments of the present invention will now be described more fully below with reference to the accompanying drawings showing embodiments of the present invention. However, the present invention can be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and the scope of the present invention will be fully conveyed to those skilled in the art. Throughout the text, the same numerals represent the same elements.

[0066] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. It will be further understood that, unless expressly defined herein, the terms used herein should be interpreted as having a meaning consistent with the meaning in the context of this specification and the relevant art, and will not be interpreted in an idealized or overly formal sense.

[0067] The present invention is described below with reference to flowcharts and / or block diagrams of methods, systems and computer program products according to embodiments of the present invention. It will be understood that some blocks of the flowchart illustrations and / or block diagrams and combinations of some blocks of the flowchart illustrations and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be stored or implemented in a microcontroller, a microprocessor, a digital signal processor (DSP), a field programmable gate array (FPGA), a state machine, a programmable logic controller (PLC) or other processing circuits, a general-purpose computer, a special-purpose computer. A computer or other programmable data processing device (e.g., a production machine) is used to create a device or block diagram block for implementing the functions / actions specified in the flowchart and / or.

[0068] These computer program instructions may also be stored in a computer-readable memory, which may direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including an instruction device to implement the functions / actions specified in the flowchart and / or block diagram.

[0069] Computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are performed on a computer or other programmable device to produce a computer-implemented process, thereby making it possible for the instructions executed on the computer or other programmable device. Other programmable devices provide steps for implementing the functions / actions specified in the flow chart and / or block diagram boxes. It should be understood that the functions / actions indicated in the boxes may not occur in the order indicated in the operation diagram. For example, depending on the functions / actions involved, two boxes shown in succession can actually be executed substantially simultaneously, or sometimes these boxes can be executed in the opposite order. Although some figures include arrows on the communication path to show the main direction of communication, it should be understood that communication can occur in the direction opposite to the arrows depicted.

[0070] Therefore, the present invention provides a method for rapid evaluation of group scheduling of a blocked flow shop. Specifically, Figure 1 As shown in the figure, taking the distributed blocking flow shop with startup time as an example, the implementation process mainly includes the following:

[0071] Step 1: Calculate the groups Artifacts in In the machine Start time on , Completion time , Leave time ;

[0072] Step 2: Calculate the group time using the start time, completion time, and departure time. Artifacts in Level ;

[0073] Step 3: The layer changes due to the insertion of the workpiece; the insertion is divided into an inter-group insertion acceleration criterion and an intra-group insertion acceleration criterion;

[0074] Based on the changes in the hierarchy, update the group Artifacts in Level And calculate the offset ;

[0075] If the acceleration criterion is inserted between groups, the specific update method is as follows:

[0076] Hypothesis Factory Include groups, try Groups inserted into the factory In order to minimize the maximum completion time, , .

[0077] Step 3.1: Set variables , if the group Insert at position q, , calculate the inserted group Start time , Completion time , Leave time ;

[0078] Step 3.2: Update The hierarchy of all artifacts at and after the location ; If all workpiece levels remain unchanged, calculate the offset ; According to the offset , fast calculation The departure time of each group after the location ; Recalculate the maximum completion time , that is ; Step 3.3: Let , ;

[0079] Step 4: Repeat steps 3.1, 3.2, and 3.3 to try all possible insertion positions in turn;

[0080] in, , , .

[0081] Optionally, the calculation method of the level in step 2 is specifically as follows:

[0082] Defining Hierarchy For Group Artifacts in In the machine Start time and machines Start time 1 The difference between the two is used to calculate the level of each artifact.

[0083] Optionally, in step 1, the calculation group Artifacts in In the machine Start time on , Completion time , Leave time The calculation formulas are as follows:

[0084]

[0085]

[0086]

[0087] in, Representation Group and Group In the machine Preparation time, Representation Group Artifacts in In the machine The processing time on Representation Group The number of workpieces in >0.

[0088] Optionally, the computing group Artifacts in Level The calculation formula is as follows:

[0089] ;

[0090] .

[0091] Optionally, in step 3.1, the calculation is performed after inserting the group Start time , Completion time , Leave time The calculation formula is as follows:

[0092]

[0093]

[0094]

[0095] Optionally, in step 3.2, the calculated offset and the maximum completion time (Right now ) is calculated as follows:

[0096]

[0097]

[0098] in, Indicates inserting the previous group Artifacts in In the machine The start time on Indicates that starting from the current group, all subsequent group levels remain unchanged.

[0099] An embodiment of the present application provides a method for rapid evaluation of group scheduling of a blocked flow shop, comprising the following steps:

[0100] Step 1: Calculate the groups Artifacts in In the machine Start time on , Completion time , Leave time ;

[0101] Step 2: Calculate the group time using the start time, completion time, and departure time. Artifacts in Level ;

[0102] Step 3: The layer changes due to the insertion of the workpiece; the insertion is divided into an inter-group insertion acceleration criterion and an intra-group insertion acceleration criterion;

[0103] Based on the changes in the hierarchy, update the group Artifacts in Level And calculate the offset ;

[0104] If the acceleration criterion is inserted within the group, the specific update method is as follows:

[0105] Group middle, Workpieces have been scheduled, of which is the number of all workpieces in the group, >0; the workpiece Insert to Group In order to minimize the maximum completion time, >0;

[0106] Step 3.1: Calculate the group Artifacts in In the machine Start time on , Completion time , Leave time ;

[0107] Step 3.2: Define the hierarchy For Group Artifacts in In the machine Start time and machines Start time 1 The difference between the two is used to calculate the level of each artifact;

[0108] Step 3.3: If the workpiece Insert into Location, , calculate the inserted group Start time , Completion time , Leave time ;

[0109] Step 3.4: Update The hierarchy of all artifacts at and after the location ; If all workpiece levels remain unchanged, calculate the offset ; According to the offset , fast calculation The departure time of each group after the location ; Recalculate the maximum completion time , that is ; Step 3.5: Let , ;

[0110] Step 4: Repeat steps 3.1, 3.2, 3.3, 3.4, and 3.5 to try all possible insertion positions in turn;

[0111] in, , , .

[0112] Optionally, the calculation method of the level in step 2 is specifically as follows:

[0113] Defining Hierarchy For Group Artifacts in In the machine Start time and machines Start time 1 The difference between the two is used to calculate the level of each artifact.

[0114] Optionally, in step 1, the calculation group Artifacts in In the machine Start time on , Completion time , Leave time The calculation formulas are as follows:

[0115]

[0116]

[0117]

[0118] in, Representation Group and Group In the machine Preparation time, Representation Group Artifacts in In the machine The processing time on Representation Group The number of workpieces in >0.

[0119] Optionally, in step 3.3, inserting the workpiece according to the calculation Start time after , Completion time , Leave time , the calculation formula is as follows:

[0120] ;

[0121] ;

[0122]

[0123]

[0124] Optionally, in step 3.4, the calculated offset and The departure time of each group after the location The calculation formula is as follows:

[0125]

[0126]

[0127] in, Indicates inserting the previous group Artifacts in In the machine The start time on Indicates that starting from the current group, all subsequent group levels remain unchanged.

[0128] Figure 2 The confidence interval comparison diagram of the present invention is shown, wherein, The proposed rapid evaluation method was applied, and This method was not applied. The performance evaluation index used was the relative percentage increase (RPI), and its calculation formula was: .in, Represents a given example, Representation method The maximum completion time obtained for this example is is the optimal maximum completion time obtained by all methods on this example. Therefore, The value range is from 0 to 1. The closer the value is to 0, the better the method The better the relative performance is. After running each example five times, calculate its The average value is recorded as the Average Relative Percentage Increase, ).from Figure 2 of It can be seen from the value that of The results were significantly better than . And, from Figure 3 Compared with the average number of iterations, The number of iterations is more, which means that it can explore the solution space more fully and finally obtain a better solution. In summary, the proposed fast evaluation method effectively shortens the calculation time of the target value and improves the performance and convergence speed of the method. In 810 test cases, of The average value is significantly lower than , which further verifies the advantages of the method of the present invention.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. After reading this application, technical personnel in the relevant field may make various modifications or changes to the present invention with reference to the above embodiments, which are all within the scope of protection claimed in the pending application of the present invention.

Claims

1. A fast evaluation method for group scheduling of a blocked flow shop, characterized in that: The following steps are involved: Step 1: Calculate the groups Artifacts in In the machine Start time on , Completion time , Leave time ; Step 2: Calculate the group time using the start time, completion time, and departure time. Artifacts in Level ; Step 3: The layer changes due to the insertion of the workpiece; the insertion is divided into an inter-group insertion acceleration criterion and an intra-group insertion acceleration criterion; Update the group Artifacts in Level And calculate the offset ; If the acceleration criterion is inserted between groups, the specific update method is as follows: Step 3.1: Set variables , if the group Insert at position q, , calculate the inserted group Start time , Completion time , Leave time ; Step 3.2: Update The hierarchy of all artifacts at and after the location ; If all workpiece levels remain unchanged, calculate the offset , and fast calculation The departure time of each group after the location ; Recalculate the maximum completion time ; Step 3.3: Order , ; Step 4: Repeat steps 3.1, 3.2, and 3.3 to try all possible insertion positions in turn.

2. The method for rapid evaluation of group scheduling of a blocked flow shop according to claim 1 is characterized in that: If the insertion in step 3 is an intra-group insertion acceleration criterion, the specific update method is as follows: Group middle, Workpieces have been scheduled, of which is the number of all workpieces in the group, >0; the workpiece Insert into group In order to minimize the maximum completion time, >0; Step 3.1: Calculate the group Artifacts in In the machine Start time on , Completion time , Leave time ; Step 3.2: Define the hierarchy For Group Artifacts in In the machine Start time and machines Start time 1 The difference between the two is used to calculate the level of each artifact; Step 3.3: If the workpiece Insert into Location, , calculate the inserted group Start time , Completion time , Leave time ; Step 3.4: Update The hierarchy of all artifacts at and after the location ; If all workpiece levels remain unchanged, calculate the offset ; According to the offset , fast calculation The departure time of each group after the location ; Recalculate the maximum completion time ; Step 3.5: Order , ; Step 4: Repeat steps 3.1, 3.2, 3.3, 3.4, and 3.5 to try all possible insertion positions in turn; in, , , .

3. The method for rapid evaluation of group scheduling of a blocked flow shop according to claim 1 or 2, characterized in that: The calculation method of the level in step 2 is specifically as follows: Defining Hierarchy For Group Artifacts in In the machine Start time and machines Start time 1 The difference between the two is used to calculate the level of each artifact.

4. The method for rapid evaluation of group scheduling of a blocked flow shop according to claim 1 or 2, characterized in that: In step 1, the calculation group Artifacts in In the machine Start time on , Completion time , Leave time The calculation formulas are as follows: ， ， ， in, Representation Group and Group In the machine Preparation time, Representation Group Artifacts in In the machine The processing time on Representation Group The number of workpieces in >

0.

5. The method for rapid evaluation of group scheduling of a blocked flow shop according to claim 3 is characterized in that: The computing group Artifacts in Level The calculation formula is as follows: ； 。 6. The method for rapid evaluation of group scheduling of a blocked flow shop according to claim 1, characterized in that: In step 3.1, the calculation is inserted into the group Start time , Completion time , Leave time The calculation formula is as follows: ， ， 。 7. The method for rapid evaluation of group scheduling of a blocked flow shop according to claim 1, characterized in that: In step 3.2, the calculated offset and The departure time of each group after the location The calculation formula is as follows: ， ， in, Indicates inserting the previous group Artifacts in In the machine The start time on Indicates that starting from the current group, all subsequent group levels remain unchanged.

8. The method for rapid evaluation of group scheduling of a blocked flow shop according to claim 2, characterized in that: In step 3.3, the insertion workpiece is calculated Start time after , Completion time , Leave time , the calculation formula is as follows: ； ； ， 。 9. The method for rapid evaluation of group scheduling of a blocked flow shop according to claim 1 or 2, characterized in that: In step 3.2 or step 3.4, the calculated offset and The departure time of each group after the location The calculation formula is as follows: ， 。

Images