A timing linkage control method and system for a coating line

Abstract

This invention relates to the field of coating production line control technology, and particularly to a time-series linkage control method and system for a coating production line. The method includes the following steps: calculating the congestion level of each workstation; identifying the workstation with the highest congestion level as the bottleneck workstation; calculating the upstream supply segment disturbance index of the bottleneck workstation; obtaining a target time horizon based on the upstream supply segment disturbance index and a preset time horizon; obtaining a buffer target value based on the target time horizon and the real-time processing rate of the bottleneck workstation, wherein the buffer target value is positively correlated with the target time horizon; and updating the buffer capacity in the DBR scheduling algorithm using the buffer target value to control the material input at the beginning of the production line, effectively improving the efficiency of the time-series linkage control of the coating production line.

Description

Technical Field

[0001] This invention relates to the field of coating production line control technology, and in particular to a timing linkage control method and system for a coating production line. Background Technology

[0002] A coating production line typically consists of multiple sequential stations, including material conveying, spraying, and drying. Its overall production efficiency highly depends on the coordinated operation of these stations. In actual production, due to varying processing capacities at each station, a bottleneck station may emerge, whose maximum capacity determines the final output of the entire production line. To address issues such as upstream material accumulation and downstream equipment idling caused by bottleneck station efficiency fluctuations, the Drum-Buffer-Pull Rope (DBR) scheduling algorithm is commonly used. This algorithm defines the bottleneck station as a drum, sets up a buffer inventory in front of it to absorb upstream fluctuations, and uses a pull rope mechanism—that is, the consumption at the bottleneck station triggers the input of materials at the beginning of the production line—to control the production cycle.

[0003] However, existing DBR scheduling algorithms have significant limitations in application. The buffer capacity, a key parameter, is usually set to a fixed value all at once. This static strategy cannot adapt to dynamic changes in the health of the production line. For example, when a device upstream of the bottleneck experiences a temporary increase in failure rate, the preset buffer capacity may be too small to effectively absorb frequent downtime disturbances, ultimately leading to frequent shutdowns at the bottleneck station due to material shortages, affecting the overall output of the production line. Conversely, when the production line is operating at its best and the upstream supply is exceptionally stable, the previously set large buffer capacity will appear redundant, unnecessarily tying up a large amount of work-in-process inventory and working capital, and potentially increasing the risk of materials deteriorating due to prolonged online time.

[0004] Therefore, how to make buffering strategies respond to real-time disturbances on the production line has become a pressing technical problem that needs to be solved to improve the intelligence and leanness of production scheduling. Summary of the Invention

[0005] To address the technical problem of how to make buffering strategies respond to real-time disturbances in the production line, this invention provides a timing-linked control method and system for a coating production line.

[0006] In a first aspect, the present invention provides a timing-linked control method for a coating production line, employing the following technical solution:

[0007] A method for time-series linkage control of a coating production line, comprising the following steps:

[0008] The system acquires operational status data from multiple serial workstations in the production line and controls the material flow based on the DBR scheduling algorithm. It calculates the congestion level of each workstation, which is positively correlated with the average number of products in the buffer zone in front of the corresponding workstation within a set time period and the number of increases in the number of products within the set time period. The workstation with the highest congestion level is identified as the bottleneck workstation. The upstream supply segment disturbance index of the bottleneck workstation is calculated; this index is the sum of the failure risks of all upstream workstations. The failure risk of each upstream workstation is positively correlated with the average repair time of the corresponding upstream workstation within a set period, negatively correlated with the average failure interval time, and negatively correlated with the distance between the upstream workstation and the bottleneck workstation. Based on the upstream supply segment disturbance index and a preset time horizon, a target time horizon is obtained. A buffer target value is obtained based on the target time horizon and the real-time processing rate of the bottleneck workstation; this target value is positively correlated with the target time horizon. The buffer capacity in the DBR scheduling algorithm is updated using the buffer target value to control the material input at the beginning of the production line.

[0009] This invention provides a method for calculating the buffer target value in an adaptive drum-buffer-pull rope scheduling algorithm, which can improve production line efficiency and reduce product waste. When dynamically identifying bottleneck workstations, this invention calculates the congestion level of each workstation by comprehensively considering the average number of products in the buffer zone in front of the workstation and the number of times the number of products increases within a set time period, accurately assessing the likelihood of congestion at each workstation. Based on this, this invention assesses the failure risk of all workstations upstream of the bottleneck workstation by comprehensively considering the average repair time, fault interval, and distance, forming an upstream supply segment disturbance index. Based on this index, the buffer target value of the buffer zone is dynamically adjusted, achieving adaptive adjustment of the buffer capacity in the DBR algorithm. This allows the buffer strategy to respond in real-time to changes in production line health, automatically increasing the buffer to ensure continuous production at the bottleneck workstation when the upstream supply is unstable, and reducing the buffer to reduce work-in-process inventory and capital occupation when the upstream is stable, significantly improving the flexibility and economy of production scheduling.

[0010] According to the present invention, a timing linkage control method for a coating production line is provided, wherein acquiring the operating status data of multiple serial workstations in the production line and controlling the material flow of the production line based on the DBR scheduling algorithm includes: real-time acquisition of start / stop timestamps and fault timestamps of each workstation in the production line; after preprocessing, obtaining the average repair time and average fault interval time of the upstream workstation based on the start / stop timestamps and fault timestamps; wherein the operating status data of the workstation includes the start / stop timestamps, fault timestamps, and the quantity of work-in-process in the upstream buffer area of ​​the workstation; and the preprocessing includes at least time synchronization, format unification, and noise reduction.

[0011] According to the timing linkage control method for a coating production line provided by the present invention, the calculation of the congestion degree of each workstation includes:

[0012] ;

[0013] For the first The level of congestion at each workstation Set duration Inner The average number of products in the buffer area in front of each workstation , Each is set for a duration Inner The workstation is at the... Time and the The number of artifacts in the buffer ahead of time. This is an indicator function.

[0014] This invention provides a specific mathematical model for calculating congestion levels. The formula combines the average number of products in the buffer zone with the frequency of quantity increases for normalization, providing an objective and quantifiable method for assessing congestion levels. This makes the identification of bottleneck workstations more accurate and automated, reducing the bias caused by relying solely on subjective judgment.

[0015] According to the timing linkage control method for a coating production line provided by the present invention, the method for obtaining the fault risk of the upstream station of the bottleneck station includes:

[0016] ;

[0017] The first bottleneck workstation The risk of failure at each upstream workstation , These are the bottleneck workstations. The average repair time and average interval between failures for each upstream workstation within a set period. For the bottleneck workstation and its first The distance between upstream workstations It is a linear normalized function. It is an exponential function with base e. This is a reference time constant.

[0018] This invention provides a method for calculating the failure risk of an upstream individual workstation. By integrating three key factors—mean repair time, mean time between failures, and physical distance from the bottleneck workstation—it can comprehensively assess the potential threat level of each upstream workstation to the stability of the bottleneck supply, making the final disturbance index assessment more accurate.

[0019] According to the present invention, a timing linkage control method for a coating production line, wherein obtaining a target time horizon based on an upstream supply segment disturbance index and a preset time horizon includes:

[0020] ;

[0021] For the target time horizon, The upstream supply disruption index for bottleneck workstations. To preset the time horizon, Based on the fundamental safe time horizon, It is a linear normalization function.

[0022] This invention, by dynamically calculating the target time horizon, combines the upstream supply segment disturbance index with the preset time horizon and the basic safety time horizon, establishing a transformation from an abstract risk index to a specific time metric, ensuring that the buffer protection time matches the actual risk level faced by the production line.

[0023] According to the timing linkage control method of the coating production line provided by the present invention, the step of obtaining the buffer target value based on the target time horizon and the real-time processing rate of the bottleneck station includes: rounding up the product of the target time horizon and the real-time processing rate of the bottleneck station as the buffer target value.

[0024] According to the timing linkage control method of the coating production line provided by the present invention, the bottleneck station acquisition method further includes: acquiring the theoretical maximum material handling rate of each station; using the product of the reciprocal of the theoretical maximum material handling rate of the station and the degree of congestion as the bottleneck index of the station; and identifying the station with the largest bottleneck index as the bottleneck station.

[0025] This invention provides another method for obtaining bottleneck workstations. By introducing the theoretical maximum material handling rate of the workstation as a correction factor, the bottleneck index is calculated by combining the actual congestion situation with the inherent processing capacity of the workstation. This can identify workstations that are not currently congested but have the lowest theoretical capacity and are most likely to become future bottlenecks, thus improving the foresight and accuracy of bottleneck identification.

[0026] According to the timing linkage control method of the coating production line provided by the present invention, the step of obtaining the theoretical maximum material handling rate of each station includes: standardizing the average unit material handling rate within a set period of each station to obtain the theoretical maximum material handling rate of that station.

[0027] According to the present invention, a timing linkage control method for a coating production line is provided, wherein updating the buffer capacity in the DBR scheduling algorithm with a buffer target value to control the material input at the beginning of the production line includes: writing the buffer target value into a parameter register through an industrial communication protocol; and inputting new materials into the buffer area in response to the actual work-in-process quantity in the buffer area of ​​the bottleneck station being lower than the buffer target value.

[0028] Secondly, the present invention provides a timing linkage control system for a coating production line, which adopts the following technical solution:

[0029] A timing linkage control system for a coating production line includes a processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the aforementioned timing linkage control method for a coating production line is implemented.

[0030] By adopting the above technical solution, a computer program is generated from the above-mentioned timing linkage control method for a coating production line, and stored in a memory for loading and execution by a processor. This allows for the creation of terminal equipment based on the memory and processor, making it convenient to use.

[0031] The present invention has the following technical effects:

[0032] Based on the above technical solutions, this invention provides a timing-linked control method and system for a coating production line, which can improve production line efficiency and reduce product waste. When dynamically identifying bottleneck workstations, this invention calculates the congestion level of each workstation by comprehensively considering the average number of products in the buffer zone in front of the workstation and the number of times the number of products increases within a set time period, thus accurately assessing the possibility of congestion at each workstation. Furthermore, this invention assesses the failure risk of all workstations upstream of the bottleneck workstation by comprehensively considering the average repair time, fault interval, and distance, forming an upstream supply disturbance index. Based on this index, the buffer target value of the buffer zone is dynamically adjusted, realizing adaptive adjustment of the buffer capacity in the DBR algorithm. This allows the buffer strategy to respond in real time to changes in the production line's health status, automatically increasing the buffer to ensure continuous production at the bottleneck workstation when the upstream supply is unstable, and reducing the buffer to reduce work-in-process inventory and capital occupation when the upstream is stable, significantly improving the flexibility and economy of production scheduling. Attached Figure Description

[0033] Figure 1 A flowchart illustrating a timing linkage control method for a coating production line provided in an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram comparing disturbance absorption capabilities provided in an embodiment of the present invention;

[0035] Figure 3This is a schematic diagram illustrating the redundancy level comparison provided for an embodiment of the present invention. Detailed Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0037] This invention discloses a time-series linkage control method for a coating production line. This method, by real-time assessment of the disturbance level in the upstream supply segment and adaptive adjustment of the buffer target value before the bottleneck station, can significantly improve the flexibility and responsiveness of production line scheduling. On the one hand, when the failure rate of upstream equipment temporarily increases or production fluctuations intensify, dynamically increasing the buffer capacity can effectively absorb the impact of short-term shutdowns or material supply interruptions, preventing frequent shutdowns at bottleneck stations due to material shortages, thereby ensuring the continuous and stable operation of key processes and improving the overall production line capacity utilization rate. On the other hand, when the stability of upstream supply improves or the production line is operating at high efficiency, automatically reducing the buffer capacity can reduce unnecessary work-in-process inventory backlog, lower the financial pressure of inventory occupation, and reduce the quality risks that may arise from materials remaining in the production process for too long, achieving optimal management of inventory and funds.

[0038] Please see details. Figure 1 As shown, Figure 1 This is a flowchart illustrating a timing-linkage control method for a coating production line provided in an embodiment of the present invention. The method specifically includes the following steps:

[0039] S1: Acquire the operating status data of multiple serial workstations in the production line, and control the material flow of the production line based on the DBR scheduling algorithm.

[0040] For example, in an embodiment of the present invention, the operation status data of multiple serial workstations in the production line are obtained, and the material flow of the production line is controlled based on the DBR scheduling algorithm. This includes: real-time collection of start and stop timestamps and fault timestamps of each workstation in the production line, and after preprocessing, obtaining the average repair time and average fault interval time of the upstream workstation based on the start and stop timestamps and fault timestamps.

[0041] The operational status data of the workstation includes the start and stop timestamps, fault timestamps, and the number of work-in-process items in the upstream buffer of the workstation. Preprocessing includes at least time synchronization, format unification, and noise reduction.

[0042] Specifically, the number of products in the buffer area of ​​each workstation can be calculated using vision sensors and / or weight sensors. After collecting data according to a preset acquisition frequency, all types of data are synchronized in time. The acquisition frequency for the number of products in the buffer area of ​​each workstation can be set to once per minute. For missing timestamps caused by sensor failure or communication interruption, if the missing time is short-term, it can be filled with the previous valid value; if the missing time is long-term, it can be marked as abnormal.

[0043] The above steps allow for the real-time acquisition of operational status data for all workstations on the coating production line.

[0044] S2: Calculate the congestion level of each workstation. The congestion level is positively correlated with the average number of products in the buffer area in front of the corresponding workstation within a set time period and the number of times the number of products increases within the set time period. Determine the bottleneck workstation based on the congestion level.

[0045] It's important to note that to adaptively adjust the buffer target value before the bottleneck station on the coating production line, it's necessary to identify the bottleneck station from all stations on the line. Since the coating production line is a series system, its overall output is constrained by only one critical constraint point at any given moment. Therefore, even if multiple stations are highly congested, the upstream congestion point will become the decisive bottleneck in the material flow direction. This congestion will cause material buildup first, preventing downstream stations, even with slower processing capabilities, from becoming the actual constraint due to insufficient material. Therefore, the higher the work-in-process inventory in the upstream buffer area of ​​a station over a period of time, the greater the congestion at that station, and the more likely it is to be a bottleneck station.

[0046] Based on this, for each workstation, the embodiments of the present invention can calculate the congestion level of each workstation within a set time period by the number of products in the buffer area upstream of the workstation, and finally determine the bottleneck workstation based on the congestion level, thereby accurately identifying key points.

[0047] The duration can be set to 30 minutes; however, the specific duration can be adjusted according to actual needs.

[0048] For example, in an embodiment of the present invention, the congestion level of each workstation is calculated to satisfy the following relationship:

[0049] ;

[0050] For the first The level of congestion at each workstation Set duration Inner The average number of products in the buffer area in front of each workstation Set duration Inner The workstation is at the... The number of artifacts in the buffer ahead of time. Set duration Inner The workstation is at the... The number of artifacts in the buffer ahead of time. This is an indicator function.

[0051] In the indicator function, if the condition within the parentheses is true, the function outputs 1; if the condition within the parentheses is false, the function outputs 0.

[0052] In the above formula, The larger the value, the higher the value within the previous set time period. The more work-in-process items a workstation has in its upstream buffer, the greater the congestion and the more likely that workstation will become a bottleneck.

[0053] This refers to the number of times the quantity of products increases within a set time period. Within the past set time period, if the first... The number of artifacts in the buffer before time step is greater than or equal to the number of artifacts at time step 1. The number of artifacts in the buffer at a given time is counted as an increase, and vice versa. This counts as a decrease, and so on, until all increases in the number of artifacts within the set time period are obtained. A larger value indicates a higher number of increases. The more work-in-process items a workstation has in its upstream cache, the greater its reliability, the greater the congestion level of that workstation, and the greater the likelihood that it will become a bottleneck workstation.

[0054] After obtaining the congestion level of each workstation based on the above steps, the key workstations affecting the efficiency of the entire system line can be identified based on the congestion level. Identifying bottleneck workstations specifically includes the following two possible implementation methods:

[0055] In one possible implementation, the workstation with the highest level of congestion can be directly identified as the bottleneck workstation.

[0056] It should be understood that the above steps can intuitively reflect the congestion level of each workstation by measuring the number of work-in-process items in the upstream buffer within the set time period. The more congested the workstation, the more likely it is to cause material backlog. Since the downstream workstations of that workstation do not have enough materials, they cannot become the real critical constraint points at the current moment.

[0057] It should be noted that a greater degree of congestion indicates a larger backlog of work-in-process upstream of that workstation, suggesting that under the current material supply and consumption conditions, that workstation is the actual bottleneck hindering material flow. However, because the coating production line operates continuously, some workstations that are not currently congested due to upstream material shortages may quickly become new congestion points later.

[0058] Based on this, embodiments of the present invention can correct the congestion level by obtaining the processing efficiency of each workstation. When the congestion levels of two workstations are relatively close, the congestion level of the workstation with lower processing efficiency will be amplified, thus making it more likely to be identified as a bottleneck. The bottleneck workstations obtained in this way are both the workstations that are currently causing backlog and the workstations whose theoretical processing capacity is most likely to cause backlog, improving the comprehensiveness and accuracy of bottleneck identification.

[0059] In another possible implementation, the bottleneck workstation is identified by: obtaining the theoretical maximum material handling rate of each workstation; multiplying the reciprocal of the theoretical maximum material handling rate of the workstation by the degree of congestion as the bottleneck index of that workstation; and identifying the workstation with the largest bottleneck index as the bottleneck workstation.

[0060] For example, in an embodiment of the present invention, obtaining the theoretical maximum material handling rate of each workstation includes: standardizing the average unit material handling rate within a set period for each workstation to obtain the theoretical maximum material handling rate of that workstation.

[0061] The set period can be 30 days; the specific period can be set according to actual needs.

[0062] After identifying the bottleneck workstation based on any of the above possible implementation methods, continue with the following steps.

[0063] S3: Calculate the upstream supply segment disturbance index of the bottleneck station. The upstream supply segment disturbance index is the sum of the failure risks of all upstream stations of the bottleneck station. The failure risk of each upstream station is positively correlated with the average repair time of the corresponding upstream station within the set period, negatively correlated with the average failure interval time, and negatively correlated with the distance between the upstream station and the bottleneck station.

[0064] It should be noted that the bottleneck workstation can be identified based on the steps described above. For the bottleneck workstation, the core of the DBR algorithm is to establish a buffer inventory area in front of it to absorb upstream fluctuations. This buffer needs to provide a sufficiently long protection period to ensure that the bottleneck workstation does not stop due to short-term upstream disruptions. Therefore, before determining the target buffer value, the degree of fluctuation in the upstream supply chain needs to be assessed.

[0065] It should be further explained that the material supply stability of the bottleneck station is affected by the shutdown of all its upstream stations. The shutdown of any station will affect the bottleneck station. Moreover, among all the upstream stations of the bottleneck station, the closer the station is to the bottleneck station, the more direct and severe the impact on the buffer zone will be if the station fails. Disturbances from distant stations may be partially smoothed out during transmission.

[0066] Based on this, embodiments of the present invention can determine the failure risk of the upstream workstation by obtaining the average repair time, average failure interval time and workstation spacing of the upstream workstation of the bottleneck workstation, and determine the upstream supply segment disturbance index of the bottleneck workstation based on this.

[0067] For example, in an embodiment of the present invention, the method for obtaining the fault risk of the upstream station of the bottleneck station satisfies the following relationship:

[0068] ;

[0069] The first bottleneck workstation The risk of failure at each upstream workstation The first bottleneck workstation The average repair time of each upstream workstation within a set period. The first bottleneck workstation The average interval between failures for each upstream workstation within a set period. For the bottleneck workstation and its first The distance between upstream workstations It is a linear normalized function. It is an exponential function with base e. This is a reference time constant.

[0070] The distance between the bottleneck station and its upstream station is the number of stations in between. The reference time constant is used to normalize the mean time between failures (MTBF) and can be set to the unit failure time, depending on actual needs.

[0071] In the above formula, The larger the value, the more likely it is to be the upstream of the bottleneck station. The greater the average repair time or the shorter the average interval between failures (MTBF) of a workstation within a past set period, the better. The higher the proportion of unavailability events at a workstation, the higher the risk of supply chain disruption, and the greater the disruption index of the upstream supply chain at the bottleneck workstation will be.

[0072] The shorter the distance between the bottleneck station and its upstream station, the more direct the impact of the material interruption caused by the upstream station on the buffer zone and the bottleneck station. Therefore, the corresponding weight will be greater when calculating the upstream supply disturbance index of the bottleneck station.

[0073] After obtaining the failure risk of each upstream station of the bottleneck station according to the above steps, the upstream supply segment disturbance index of the bottleneck station can be obtained. The larger the upstream supply segment disturbance index of the bottleneck station, the greater the fluctuation of the upstream supply segment.

[0074] Thus, after obtaining the fluctuation level of the upstream supply segment through the above steps, the present invention can determine the protection time required for the buffer to effectively absorb these disturbances. This can avoid the bottleneck station from shutting down due to insufficient buffer capacity, and also avoid the work-in-process stockpiling, capital occupation, and increased risk of material deterioration due to excessive buffer capacity. That is, the following steps are performed.

[0075] S4: Based on the upstream supply segment disturbance index and the preset time horizon, the target time horizon is obtained; the buffer target value is obtained according to the target time horizon and the real-time processing rate of the bottleneck station, and the buffer target value is positively correlated with the target time horizon; the buffer capacity in the DBR scheduling algorithm is updated using the buffer target value to control the material input at the beginning of the production line.

[0076] It should be noted that the upstream supply disruption index of the bottleneck station can be obtained according to the above steps. The essential function of the buffer is to provide a time window for the bottleneck station to continue production when the upstream supply is interrupted.

[0077] Therefore, embodiments of the present invention can transform the upstream supply segment disturbance index into a specific time metric, namely, how long the buffer needs to provide protection to effectively absorb upstream disturbances, and the length of the time window should be positively correlated with the level of risk faced.

[0078] For example, in an embodiment of the present invention, a target time horizon is obtained based on the upstream supply segment disturbance index and a preset time horizon, satisfying the following relationship:

[0079] ;

[0080] For the target time horizon, The upstream supply disruption index for bottleneck workstations. To preset the time horizon, Based on the fundamental safe time horizon, It is a linear normalization function.

[0081] The preset time horizon can be set to 60 seconds, and the basic safety time horizon can be set to 10 seconds. The specific settings for the preset time horizon and the basic safety time horizon can be determined according to actual needs. Since the upstream supply disturbance index of the bottleneck station may be 0, the basic safety time horizon is set to cover the normal fluctuations when the upstream supply disturbance index is 0.

[0082] In the above formula, the larger the upstream supply disturbance index of the bottleneck station, the higher the upstream risk and the more protection time is needed for buffering, and therefore the larger the corresponding target time horizon. Conversely, the smaller the upstream supply disturbance index of the bottleneck station, the smaller the upstream fluctuation and the smaller the corresponding target time horizon.

[0083] It should be understood that the physical capacity of the buffer depends not only on the duration required, but also on the material consumption rate during that period. Therefore, after obtaining the target time horizon according to the above steps, the embodiment of the present invention can also obtain the final buffer target value based on the target time horizon and the real-time processing rate of the bottleneck station.

[0084] For example, in an embodiment of the present invention, obtaining a buffer target value based on the target time horizon and the real-time processing rate of the bottleneck station includes: rounding up the product of the target time horizon and the real-time processing rate of the bottleneck station to obtain the buffer target value.

[0085] After obtaining the adaptive buffer target value for the bottleneck station based on the above steps, this buffer target value is updated in real time to the production line central control system. The system will use this buffer target value as the target capacity of the buffer zone in front of the current bottleneck station. The rope feeding decision and related control logic at the beginning of the production line will be adjusted based on the dynamically identified bottleneck and its dynamically calculated buffer target value.

[0086] For example, in an embodiment of the present invention, updating the buffer capacity in the DBR scheduling algorithm using a buffer target value to control the material input at the beginning of the production line includes: writing the buffer target value into a parameter register via an industrial communication protocol; and inputting new materials into the buffer area in response to the actual work-in-process quantity in the buffer area of ​​the bottleneck station being lower than the buffer target value.

[0087] Specifically, since the total amount of work-in-process (WIP) on the production line cannot exceed the target capacity of the buffer zone, a permission signal to feed one unit is sent to the feeding station at the front of the production line after each finished product is completed. Upon receiving the permission signal, the feeding station feeds a new unit of raw material into the production line. If no signal is received, feeding must stop, and the line must wait for the next pull. When the buffer target value increases, the rope lengthens, allowing more WIP to exist on the production line simultaneously. When the buffer target value decreases, the rope shortens to strictly limit the total amount of WIP.

[0088] The above steps enable time-series linkage control of the coating production line. In this control, when upstream supply is interrupted and the line stops, the disturbance absorption capacity can be assessed by evaluating the buffer inventory's ability to protect downstream bottleneck stations from material shortages. Only at this point does the buffer inventory begin to be depleted to maintain the bottleneck station's operation. The ratio of the actual buffer level to the target buffer value reflects whether the remaining buffer inventory is sufficient to absorb disturbances when a risk occurs.

[0089] Redundancy is used to assess the percentage by which the buffer inventory exceeds the target capacity throughout the entire period. To obtain this value, the difference between the actual buffer level and the target buffer value at a given moment can be calculated. The percentage ratio of this difference to the target buffer value is taken as the redundancy level at that moment. Redundancy reflects the economy and leanness of the production line control strategy. A high redundancy level indicates significant waste in the buffer settings, leading to unnecessary capital and inventory, and increasing the risk of material spoilage or quality issues.

[0090] Therefore, the efficiency of the buffer target value obtained by the adaptive strategy in this embodiment of the invention and the efficiency of the traditional fixed strategy can be evaluated by the perturbation absorption capability and redundancy. Please refer to [link to relevant documentation]. Figure 2 and Figure 3 As shown, Figure 2 This is a schematic diagram illustrating a comparison of disturbance absorption capabilities provided by an embodiment of the present invention. Figure 3 This is a schematic diagram illustrating a redundancy comparison in an embodiment of the present invention. When acquiring disturbance absorption capability and redundancy, several time points are obtained from the historical time period at the current moment. The average disturbance absorption capability during the shutdown phase at these several time points, and the average redundancy across the entire phase, are used as the disturbance absorption capability and redundancy assessed at the current moment.

[0091] Combination Figure 2 and Figure 3 As can be seen, compared with the traditional fixed strategy, the adaptive strategy provided by the embodiments of the present invention significantly improves the disturbance absorption capability during the shutdown phase by adaptively calculating the buffer target value at each time moment, and significantly reduces the redundancy throughout the entire phase.

[0092] As can be seen, in this embodiment of the invention, when implementing the time-series linkage control of the coating production line, the operating status data of multiple serial workstations in the production line can be obtained, and the material flow of the production line can be controlled based on the DBR scheduling algorithm; the congestion level of each workstation is calculated, and the congestion level is positively correlated with the average number of products in the buffer area in front of the corresponding workstation within a set time period and the number of times the number of products increases within the set time period; the workstation with the highest congestion level is determined as the bottleneck workstation; the upstream supply section disturbance index of the bottleneck workstation is calculated, and the upstream supply section disturbance index is the sum of the failure risks of all upstream workstations of the bottleneck workstation; each The failure risk of upstream workstations is positively correlated with the average repair time of the corresponding upstream workstations within a set period, negatively correlated with the average failure interval time, and negatively correlated with the distance between upstream workstations and bottleneck workstations. Based on the upstream supply segment disturbance index and the preset time horizon, the target time horizon is obtained. The buffer target value is obtained according to the target time horizon and the real-time processing rate of the bottleneck workstation, and the buffer target value is positively correlated with the target time horizon. The buffer capacity in the DBR scheduling algorithm is updated using the buffer target value to control the material input at the beginning of the production line, which effectively improves the efficiency of the timing linkage control of the coating production line.

[0093] This invention also discloses a timing linkage control system for a coating production line, including a processor and a memory. The memory stores computer program instructions, and when the computer program instructions are executed by the processor, a timing linkage control method for a coating production line provided by this invention is implemented.

[0094] The system also includes other components well known to those skilled in the art, such as communication buses and communication interfaces, the settings and functions of which are known in the art and will not be described in detail here.

[0095] In this invention, the aforementioned memory can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0096] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A timing-linked control method for a coating production line, characterized in that, include: Acquire the operating status data of multiple serial workstations in the production line, and control the material flow of the production line based on the DBR scheduling algorithm; Calculate the congestion level at each workstation, including: ； For the first The level of congestion at each workstation Set duration Inner The average number of products in the buffer area in front of each workstation , Each is set for a duration Inner The workstation is at the Time and the The number of artifacts in the buffer ahead of time. For indicator functions, It is a linear normalization function; The workstation with the most congestion was identified as the bottleneck workstation. Calculate the upstream supply disturbance index of the bottleneck station. The upstream supply disturbance index is the sum of the failure risks of all upstream stations of the bottleneck station. Methods for assessing the failure risk of upstream workstations of bottleneck workstations include: ； The first bottleneck workstation The risk of failure at each upstream workstation , These are the bottleneck workstations. The average repair time and average interval between failures for each upstream workstation within a set period. For the bottleneck workstation and its first The distance between upstream workstations It is an exponential function with base e. For reference time constant; Based on the upstream supply disturbance index and the preset time horizon, the target time horizon is obtained; the buffer target value is obtained according to the target time horizon and the real-time processing rate of the bottleneck station, and the buffer target value is positively correlated with the target time horizon. Update the buffer capacity in the DBR scheduling algorithm using the buffer target value to control the material input at the beginning of the production line; The methods for identifying bottleneck workstations also include: obtaining the theoretical maximum material handling rate of each workstation; using the product of the reciprocal of the theoretical maximum material handling rate of the workstation and the degree of congestion as the bottleneck index of that workstation; and identifying the workstation with the largest bottleneck index as the bottleneck workstation.

2. The timing linkage control method for a coating production line according to claim 1, characterized in that, The step of acquiring the operating status data of multiple serial workstations in the production line and controlling the material flow of the production line based on the DBR scheduling algorithm includes: The start and stop timestamps and fault timestamps of each workstation in the production line are collected in real time. After preprocessing, the average repair time and average fault interval time of the upstream workstation are obtained based on the start and stop timestamps and fault timestamps. The operating status data of the workstation includes the start and stop timestamps, fault timestamps, and the number of work-in-process in the upstream buffer area of ​​the workstation. The preprocessing includes at least time synchronization, format unification, and noise reduction.

3. The timing linkage control method for a coating production line according to claim 1, characterized in that, The process of obtaining the target time horizon based on the upstream supply segment disturbance index and a preset time horizon includes: ； For the target time horizon, The upstream supply disruption index for bottleneck workstations. To preset the time horizon, Based on the fundamental safe time horizon, It is a linear normalization function.

4. The timing linkage control method for a coating production line according to claim 1, characterized in that, The process of obtaining the buffer target value based on the target time horizon and the real-time processing rate of the bottleneck workstation includes: The target time horizon is multiplied by the real-time processing rate of the bottleneck station and then rounded up to obtain the buffer target value.

5. The timing linkage control method for a coating production line according to claim 1, characterized in that, The process of obtaining the theoretical maximum material handling rate for each workstation includes: The average unit material handling rate within a set cycle for each workstation is standardized to obtain the theoretical maximum material handling rate for that workstation.

6. The timing linkage control method for a coating production line according to claim 1, characterized in that, The method of updating the buffer capacity in the DBR scheduling algorithm using the buffer target value to control the material input at the beginning of the production line includes: The buffer target value is written to the parameter register via the industrial communication protocol; in response to the actual work-in-process quantity in the buffer area of ​​the bottleneck station being lower than the buffer target value, new materials are added to the buffer area.

7. A timing-linked control system for a coating production line, characterized in that, include: A processor and a memory, wherein the memory stores computer program instructions that, when executed by the processor, implement a timing linkage control method for a coating production line according to any one of claims 1-6.

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