JP5803693B2 - Production logistics schedule creation system and production logistics schedule creation method - Google Patents

Description

  The present invention relates to a production logistics schedule creation system and a production logistics schedule creation method for creating a work schedule of a production logistics process including a plurality of processes each of which executes processing in units of lots in which one or more products are collected. It is.

  Generally, in the manufacturing industry, a final product or a semi-finished product (hereinafter, the final product and the semi-finished product are simply referred to as a product) is manufactured from raw materials through a plurality of processes. The final product means a finished product, and the semi-finished product means a product in a manufacturing process that has been processed in units of processes but has not yet reached the final product. For example, a steel product is manufactured by executing a plurality of processes such as a steelmaking process, a hot rolling process, a cold rolling process, and a plating process according to a predetermined order according to product specifications. Hereinafter, the plurality of ordered processes is referred to as a multistage process. However, which process is adopted in the manufacturing process of a certain product differs depending on the product specifications and the like. For this reason, not all products are manufactured through the same multistage process.

  In a production logistics process including multi-stage processes, for example, lots are created for each process in order to simplify and improve operational conditions, manufacturing work, sorting work, etc., and products are produced in units of lots in each process. Here, a lot means a production unit in which products that can be processed by operations (manufacturing operations and sorting operations) under the same conditions are combined, and a plurality of products produced in each process are combined into one group. is there. For example, one lot is a group of 10 coils manufactured in a hot rolling process. Accordingly, in each process, a plurality of products collected in one lot are continuously produced. Hereinafter, a process of continuously producing a plurality of products collected in one lot is referred to as a lot process. In addition, an operation for collecting a plurality of products into one lot is called lot-sizing processing.

  In the work schedule for each process, a plurality of jobs are registered in units of lots created by the lot summarization process. At this time, the job registration order is generally determined using a method for solving a so-called scheduling problem. In each process, lot processing is sequentially performed according to the work schedule created for itself. Here, when the lot processing for the preceding lot is completed, the lot processing for the subsequent lot is executed. At this time, the setup change operation is performed between the preceding lot processing and the subsequent lot processing. I need it. The setup change work means parts replacement, maintenance, etc. of equipment for executing each process. Specifically, examples of the setup change operation include replacement of a rolling roll in a hot rolling process and replacement of a tundish in a continuous casting process. This setup change operation usually takes a lot of time. For this reason, it is desirable that the work schedule for each process be created so that the number of setup change work is as small as possible.

  However, when a plurality of products are grouped into lots, it is necessary to satisfy a constraint condition based on the product specifications (hereinafter referred to as product requirements), and thus not all products are grouped into the same lot. Also, even if they are grouped together in the same lot, if the lot is unnecessarily enlarged, a product with sufficient time before delivery will be manufactured first, and as a result, it will be manufactured first. There is a case where the product to be deferred. For this reason, there is a possibility of causing a problem that the production of the postponed product is not in time for delivery.

  Such a problem is a problem that may occur not only in the production process but also in the physical distribution process. For example, if you create a work schedule that divides products for the same customer into several vessels and loads them, load products that have time allowance before delivery to the vessel that departs first, and the delivery date is It may cause a problem that a work schedule is created for loading a looming product on a ship that sails later. In general, the product requirements for collecting lots are different for each process. For this reason, when several types of products are produced using a plurality of processes, the order of lot processing in the subsequent process does not always follow the order of lot processing in the previous process. That is, the product produced by the lot process registered at the beginning in the work schedule of the preceding process is not necessarily processed by the lot process registered at the beginning in the work schedule of the subsequent process.

  From the above, when creating a work schedule for a production logistics process including a plurality of processes, it is desirable to create a work schedule for all processes in order to improve production efficiency. However, the following problems arise when trying to create a work schedule for all processes. The first problem is that an enormous amount of calculation and a lot of time are required to find a solution because the schedule problem to be solved becomes large. In particular, when creating a work schedule covering all processes including production processes and logistics processes, the schedule problem to be solved becomes larger, so a huge amount of calculation and a lot of time are required to find the solution. Cost. The second problem is that the progress of the created work schedule is easily affected by external factors such as process delay and work stoppage, but the schedule problem is large-scale, and The work schedule cannot be corrected quickly.

  For this reason, until now, the work schedule over all processes was created by hierarchizing the schedule problem which should be solved using the method of nonpatent literature 1 and patent literature 1. Specifically, the method described in Non-Patent Document 1 divides a plan creation period into a plurality of periods, and after determining the amount of products manufactured in each period, creates a detailed work schedule for each period. . Moreover, the method of patent document 1 creates the work schedule of a multistage process by repeatedly performing the process which creates the work schedule over all the processes by creating the work schedule of a designated time slot | zone in order from an upstream process. Is.

JP 2008-123359 A

Tamura, "Large-scale systems-modeling, control, decision-making", Chapter 5 (Large-scale mathematical programming-development of constructive methods-), Shosodo

  However, when a work schedule for a multistage process is created using the method described in Non-Patent Document 1, the problem of determining the amount of product manufactured in each period becomes very complicated. In addition, since the range for the problem of determining the amount of the product covers all processes, when the operation condition changes in some process, the amount of the product manufactured in each period changes. For this reason, in order to realize the processing to determine the amount of products manufactured in each period with a computer, it corresponds to the high speed of calculation that outputs the calculation result in practical time and the change of operating conditions for complicated problems However, Non-Patent Document 1 does not describe a countermeasure. Further, in lot production, there are fine operation restrictions such as setup change restrictions and restriction conditions related to the processing order in the lot. It is difficult to consider detailed operation restrictions when determining the amount of product manufactured in each period by the method described in Non-Patent Document 1, and there is a possibility that the product amount in each period and the work schedule in each period may deviate. is there. However, Non-Patent Document 1 does not describe the countermeasures.

  On the other hand, in the method described in Patent Document 1, in order to create a work schedule in order from the upstream process, it is likely to be a work schedule that neglects the efficiency of the downstream process, and creates a work schedule that improves the production efficiency of the entire multistage process. It ’s difficult. In addition, the method described in Patent Document 1 assumes that a work schedule of a process in which a plurality of steps are continuously arranged is created, and a process that passes according to a product in a process including a plurality of steps. It does not describe how to create work schedules for different cases.

  For the above reasons, even if the methods described in Non-Patent Document 1 and Patent Document 1 are used, a work schedule for all processes can be easily and quickly performed without requiring a huge amount of calculation and a lot of time. Cannot be created or modified.

  The present invention has been made in view of the above problems, and its purpose is to create or modify a work schedule for all processes easily and quickly without requiring a huge amount of calculation and a lot of time. A production logistics schedule creation system and a production logistics schedule creation method are provided.

  In order to solve the above-described problems and achieve the object, a production logistics schedule creation system according to the present invention includes a plurality of processes each of which executes processing using a lot in which one or more products are collected as a processing unit. A production logistics schedule creation system for creating work schedules for processes, which stores at least information on the process through which products pass, the types of lots in which products are collected in each process, the delivery date of products, and the past work schedule of each process And classifying the product into a plurality of items based on the process through which the product passes and the type of lot in which the product is collected in each process, based on the information stored in the storage unit, and within the planning period Item processing amount calculation means for calculating the processing amount for each item in each period, and the item processing amount calculation means Based on the processing amount of each material in each period in the calculated planning period Te, characterized in that it comprises a work schedule creating means for creating a work schedule for each process in planning period.

  In the production distribution schedule creation system according to the present invention, in the above invention, the item processing amount calculation means uses the information of the past work schedule of each process stored in the storage means, and the initial inventory of each item. Derived by deriving an input / output relational expression with at least one of quantity, order quantity, and shipping quantity as input items, and the accumulated processing amount or processing amount for each item in each period within the plan creation period as output items. The processing amount for each item in each period within the plan creation period is calculated using the input / output relational expression.

  In the production distribution schedule creation system according to the present invention, in the above invention, the item processing amount calculation unit calculates an evaluation value of a past work schedule, and stores information on a past schedule in which the calculated evaluation value is a predetermined value or more. The input / output relational expression is derived by using.

  In the production distribution schedule creation system according to the present invention, in the above invention, the item processing amount calculation means uses information of a past schedule in which the evaluation value is equal to or greater than a predetermined value, and uses an initial inventory amount and an order amount of each item. , And at least one of the shipping quantity as an input item, and derive a linear regression equation that uses the accumulated processing amount or processing amount for each item in each period within the planning period as an output item. The input / output relational expression is used.

  In the production distribution schedule creation system according to the present invention, in the above invention, the item processing amount calculation means calculates an evaluation value of a past work schedule, and the past evaluation information whose calculated evaluation value is a predetermined value or more is calculated. Based on this, at least one of a maximum value and a minimum value of the processing amount for each item is determined, and an input / output relational expression is derived using this as a constraint.

  In the production distribution schedule creation system according to the present invention, in the above invention, the item processing amount calculation unit calculates an evaluation value of a past work schedule, and stores information on a past schedule in which the calculated evaluation value is a predetermined value or more. Extracting and calculating a processing amount for each item so that a processing amount error with the extracted data is minimized.

  In the production distribution schedule creation system according to the present invention, in the above invention, the item processing amount calculation unit calculates an evaluation value of a past work schedule, and stores information on a past schedule in which the calculated evaluation value is a predetermined value or more. Extracting and determining at least one of the maximum value and the minimum value of the processing amount for each item based on the extracted information, and processing the extracted data with the maximum value and the minimum value of the processing amount for each item as a constraint The processing amount for each item is calculated so that the amount error is minimized.

  In order to solve the above-described problems and achieve the object, a production logistics schedule creation method according to the present invention includes a plurality of processes each of which executes processing using a lot in which one or more products are collected as a processing unit. A production logistics schedule creation method for creating a work schedule for a process, wherein the products are classified into a plurality of items based on the process through which the products pass and the types of lots in which the products are collected in each process. A step of calculating a processing amount for each item in the period, and a step of creating a work schedule for each process in the plan creation period based on the processing amount for each item in each period in the plan creation period.

  According to the production logistics schedule creation system and the production logistics schedule creation method according to the present invention, products are classified into a plurality of items, the processing amount for each item in each period within the plan creation period is calculated, and the product within the plan creation period is calculated. Create a work schedule for each process based on the amount of processing for each item in each period, so you can easily or quickly create or modify a work schedule for all processes without requiring enormous amounts of calculation and much time. it can. Further, since the processing amount is calculated based on the past information, a deviation between the calculated processing amount for each item and the work schedule of each process can be suppressed, and an efficient work schedule can be generated.

FIG. 1 is a diagram illustrating an example of a product distribution process for which a work schedule is created. FIG. 2 is a block diagram showing a configuration of a production distribution schedule creation system according to an embodiment of the present invention. FIG. 3 is a diagram illustrating an example of order information stored in the order DB. FIG. 4 is a diagram illustrating an example of a lot type. FIG. 5 is a diagram illustrating an example of item throughput information stored in the all process plan information DB. FIG. 6 is a flowchart showing the flow of item throughput calculation processing according to an embodiment of the present invention. FIG. 7 is a schematic diagram for explaining a normal stock quantity and a ladder stock quantity. FIG. 8 is a diagram illustrating an example of the shipping plan information. FIG. 9 is a diagram showing the shipping request amount of the steel product for each destination calculated from the shipping plan information shown in FIG. FIG. 10 is a flowchart showing the flow of schedule creation processing according to an embodiment of the present invention. FIG. 11 is a diagram illustrating an example of a constraint condition related to a work schedule for cold rolling. FIG. 12 is a flowchart showing the flow of item throughput calculation processing according to an embodiment of the present invention. FIG. 13 is a diagram showing variable names corresponding to the order quantity for each size for calculating the weighting coefficient used in the item throughput calculation process according to the embodiment of the present invention. FIG. 14 is a diagram showing the lot type of each process used in the example of the present invention. FIG. 15 is a diagram showing a part of the shipping plan information used in the embodiment of the present invention. FIG. 16 is a diagram showing the result of numerical calculation performed in the example of the present invention.

  Hereinafter, the configuration and operation of a production distribution schedule creation system according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, as shown in FIG. 1, an object for creating a work schedule is a production logistics process for thin plate products in steel manufacturing. The target process includes a cold rolling facility, an annealing facility, a plating facility, and a shipping facility, and the process names are referred to as process A, process B, process C, and process D, respectively. In this production logistics process, steel products are either (1) Step A → Step B → Step C → Step D, (2) Step A → Step B → Step D, and (3) Step A → Step D. It is processed in the process route. In other words, in this production distribution process, the process route that passes through varies depending on the steel product. And in process D, the steel products of the same destination are put together in a group for one ship and are loaded. However, the production distribution process for which the present invention creates a work schedule is not limited to the production distribution process shown in FIG.

[Configuration of production logistics schedule creation system]
First, with reference to FIGS. 2 to 5, the configuration of a production distribution schedule creation system according to an embodiment of the present invention will be described.

  FIG. 2 is a block diagram showing a configuration of a production distribution schedule creation system according to an embodiment of the present invention. As shown in FIG. 2, the production distribution schedule creation system 1 according to an embodiment of the present invention includes a cold rolling equipment (cold pressure equipment) management system 2, an annealing equipment management system 3, a plating equipment management system 4, and shipping equipment. A management system 5, a database (DB) server 6, and an item throughput calculation device 7 are provided as main components.

  The cold pressure equipment management system 2, the annealing equipment management system 3, the plating equipment management system 4, and the shipping equipment management system 5 are configured by an information processing device such as a workstation or a personal computer. The cold pressure equipment management system 2, the annealing equipment management system 3, the plating equipment management system 4, and the shipping equipment management system 5 use the information stored in the DB server 6, respectively. B, a process C, and a function of creating a work schedule of process D, and a function of collecting information indicating the progress of work in each process. Each management system functions as work schedule creation means according to the present invention.

  The DB server 6 is configured by an information processing apparatus such as a workstation or a personal computer. The DB server 6 includes a cold pressure facility management system 2, an annealing facility management system 3, a plating facility management system 4, a shipping facility management system 5, and an item throughput calculation device via a telecommunication line such as a LAN (Local Area Network). 7 is connected. The DB server 6 functions as a storage unit according to the present invention. The DB server 6 includes an order DB 6a, a production / distribution progress DB 6b, a process plan DB 6c, and an all process plan information DB 6d.

  The order DB 6a stores order information for steel products. FIG. 3 is a diagram illustrating an example of order information stored in the order DB 6a. As shown in FIG. 3, the order information includes unique identification information (product ID) assigned to each steel product, and the width, thickness, weight, component, delivery date for each process corresponding to the product ID, And lot type information. The lot type means a type of lot in which steel products corresponding to the product ID are collected, and is set for each process. For example, when the lot type shown in FIG. 4 is set for each of the process A (cold pressure equipment), the process B (annealing equipment), the process C (plating equipment), and the process D (shipping equipment), One of the lot types C1 and C2 is specified for the steel product to be processed. In each equipment, steel products of the same lot type are processed in the same lot, and when the lot changes, setup work such as equipment replacement and maintenance of the equipment is required. As for the shipping equipment, since the steel products with the same destination can be loaded and shipped on the same ship, the destination is set as the lot type.

  The production / distribution progress DB 6b includes information indicating the progress of work in each process periodically transmitted from the cold pressure equipment management system 2, the annealing equipment management system 3, the plating equipment management system 4, and the shipping equipment management system 5. Stored as processing status information. The processing status information includes information related to the stock quantity of steel products in each of the processes A to D. The process-by-process plan DB 6c is a work schedule for each process of the processes A to D created in the past, constraint condition information indicating constraint conditions for creating a work schedule for each process of the processes A to D, and evaluation of the work schedule. It stores information on the future work schedule of each of the processes A to D created by the index and schedule creation processing described later.

  The constraint condition information includes information related to the setup change time, lot grouping conditions, and work predecessor / successor conditions for each of the processes A to D. The setup change time means the time required for the setup change work. Lot summarizing conditions mean conditions such as width, thickness, weight, and composition of steel products that can be grouped into one lot. The work predecessor / succeeding condition means a condition for determining the processing order of work in each of the processes A to D. Examples of the work schedule evaluation index include lead time, delivery margin, inventory quantity, and the like.

  The all process plan information DB 6d stores item throughput information as shown in FIG. 5 created by the item throughput calculator 7. Details of the item throughput information will be described later. The item processing amount calculation device 7 is configured by an information processing device such as a workstation or a personal computer, and the operation of the entire item processing amount calculation device 7 is controlled by a CPU in the information processing device executing a control program. The item throughput calculation device 7 functions as an item throughput calculation unit according to the present invention.

  The production logistics schedule creation system 1 having such a configuration is easy and quick without requiring enormous calculation amount and much time by executing the following item throughput calculation processing and schedule creation processing. The work schedule over all the steps of the production logistics process shown in FIG. 1 can be created or modified. Hereinafter, with reference to the flowcharts shown in FIG. 6 and FIG. 10, the operation of the production distribution schedule creation system 1 when executing the item throughput calculation process and the schedule creation process will be described.

[Item throughput calculation processing]
First, the operation of the production distribution schedule creation system 1 when executing the item throughput calculation process will be described with reference to the flowchart shown in FIG.

  FIG. 6 is a flowchart showing the flow of item throughput calculation processing according to an embodiment of the present invention. The flowchart shown in FIG. 6 starts every predetermined control cycle, and the item throughput calculation process proceeds to the process of step S1.

  In the process of step S1, the item throughput calculation device 7 is stored in the order information stored in the order DB 6a, the inventory information of each process stored in the production / distribution progress DB 6b, and the process plan DB 6c. Information on the past work schedule of each process is read out. Then, the item throughput calculation device 7 calculates an evaluation value of the past work schedule of each read process. Specifically, the item processing amount calculation device 7 determines for each work schedule an evaluation value indicating the quality of the work schedule, such as whether the work schedule has good production / distribution efficiency, and how similar the work schedule condition to be created is. Three types of evaluation values are calculated: an evaluation value that indicates the degree of similarity to the current schedule creation conditions, such as whether the work is being performed, and an evaluation value that indicates a difference from the execution result of the work schedule, such as whether the work has been performed according to the work schedule Then, the weighted sum of each evaluation value is calculated as the evaluation value of the work schedule.

  Here, as an evaluation value indicating the quality of the work schedule, throughput (processing amount), delivery rate achievement ratio, setup cost, average inventory amount, and the like can be exemplified. Examples of the evaluation value indicating the degree of similarity include an order quantity and an inventory quantity for each item, and a planned shipment quantity for each destination. Moreover, in this embodiment, the item means a group in which steel products having the same process route passing through and the same lot type in each process are collected. For example, in the present embodiment, the steel products processed in the order of steps A to D, and processed in lot type A1 in process A, lot type B2 in process B, lot type C2 in process C, and lot type D1 in process D. Define the group as item 1. A plurality of groups of products having the same lot type may be collected as items. Thereby, the number of items can be suppressed when the number of lot types is large. Thereby, the process of step S1 is completed, and the item throughput calculation process proceeds to the process of step S2.

  In the process of step S2, the item processing amount calculation device 7 selects a past work schedule in which the evaluation value calculated by the process of step S1 is a set value or more as a work schedule used in the subsequent processes. Thereby, the process of step S2 is completed, and the item throughput calculation process proceeds to the process of step S3.

  In the process of step S3, the item processing amount calculation device 7 calculates a coefficient (parameter) of a linear regression equation for determining the processing amount for each period of the item. Below, the calculation method of the coefficient of a linear regression equation is demonstrated, dividing into the case where the objective variable of a linear regression equation is a cumulative processing amount, and the case where it is the processing amount for every period. First, a method for calculating a coefficient of a linear regression equation when the objective variable of the linear regression equation is a cumulative processing amount will be described.

When the objective variable of the linear regression equation is the cumulative processing amount, the item processing amount calculation device 7 uses the past work schedule selected by the processing in step S2, and the processing amount for each item and the period within the planning target period. Deriving a linear regression equation for calculating In the present embodiment, the item processing amount calculation device 7 uses the past work schedule selected by the processing in step S2 to determine the coefficient of the linear regression equation expressed by the following equation (1). Deriving a linear regression equation.

Here, in the above formula (1), the parameter x _j (j = 1 to n) is an explanatory variable, and is the initial stock quantity for each item and process, the order quantity for each period t within the item and the plan creation period. , Items and the minimum shipping quantity for each period t within the plan creation period, and the shipping demand quantity of steel products for each destination. Further, the parameter y ^{i, t} is an objective variable and represents the accumulated processing amount for each item and process in the period t within the planning target period. In addition, i is an index (see FIG. 5) assigned to each item and process, and the initial stock quantity for each item and process is set as the value of the parameter y ^{i, 0} at the start of the planning target period (t = 0). Is done.

  The initial stock quantity for each item and process means a ladder stock quantity at the beginning of the planning target period. That is, as shown in FIG. 7, the normal inventory quantity is decreased by the process in the downstream process, but the trapezoidal inventory quantity is a value including the inventory quantity processed in the downstream process. The order quantity for each period t in the item and the plan creation period means the order quantity of steel products that have been put in for each period t in the item and the plan creation period, and can be executed by each period. It can be determined by calculating the total weight of the order. Since the order quantity for each item and period t within the plan creation period is calculated as an integrated value from the beginning of the planning target period, the order quantity of each item is monotonously non-decreasing as time passes. The order quantity for each item is equal to the quantity of items that may be manufactured by each period.

  The minimum shipment quantity for each period t within the item and the plan creation period means the total value of the quantity of items for which the processing deadline in the target process is set before each period, and is attached to each order. It can be calculated from the delivery date for each process. The requested amount of steel products for each destination means the amount of items that have been manufactured by the period immediately before the period including the shipping start time, and is calculated from the shipping plan information as shown in FIG. Can do. The shipping plan information shown in FIG. 8 includes information on ship name, destination (steel product unloading port), shipping start time, shipping completion time, and minimum loading capacity. As shown in FIG. 9, the requested shipping amount of the steel product for each destination can be calculated by collecting the minimum loading amount at the same destination. Note that period 1 and period 2 in FIG. 9 mean, for example, the period from 6:00 am to 15:00 pm on the 12th and the period from 15:00 pm on the 12th to midnight on the 13th. The period within the period is shown. The subsequent period 3 means a period from midnight to 6:00 am on the 13th.

The item throughput calculator 7 calculates the difference between the value on the left side and the value on the right side when the values obtained from the past work schedule are substituted for the explanatory variable x _j and the objective variable y ^{i, t} (the following formula ( 2) is used as an error value, and the coefficient of the linear regression equation is determined so as to minimize the sum of squares of the error value. That is, the item throughput calculation device 7 determines the coefficient of the linear regression equation so as to minimize the value of the following formula (3). In Equation (3), the parameter x _j ^k indicates the value of the j-th explanatory variable in the k-th past work schedule, and the parameter y _k ^{i, t} is the objective variable related to the k-th past work schedule. The values of y ^{i, t} are shown. Parameters w _{k, i, t} indicate weighting factors when the k-th past work schedule is used in the calculation of the ladder stock quantity of the item / process i, period t. Here, the weighting factors w _{k, i, t} are the similarity between the past data and the calculation target data regarding the vector composed of explanatory variables and other operation parameters, and the evaluation value calculated in the process of step S2. Can be given as a function.

  The coefficient of the linear regression equation may be determined by performing a normal regression calculation, or may be obtained as a quadratic programming problem or a non-linear programming problem by adding various constraints (secondary programming problem). (For example, see References (by Hiroshi Konno and Hiroshi Yamashita, Nonlinear Programming, Nikka Giren) for solutions to problems.) In this case, examples of the constraint conditions to be added include the following constraint conditions. Thereby, the process of step S3 is completed, and the item throughput calculation process proceeds to the process of step S4.

[Restriction condition 1: Order quantity restriction]
When the passing process of the item / process i in the period t is the first process of the production logistics process, the index corresponding to the order quantity of the item / process i is PO (i), and the order quantity up to the period t is O ^{PO (i ), T} , the accumulated processing amount y ^{i, t} of the item / process i up to the period t is equal to or less than the order quantity O ^{PO (i), t of} the item corresponding to the index i up to the period t. The accumulated processing amount y ^{i, t} of the item / process i up to t must satisfy the following formula (4).

[Restriction condition 2: Minimum shipment volume restriction]
When the passing process of the item / process i in the period t is the process immediately before the shipment of the production logistics process, the index of the minimum shipment amount of the item corresponding to the index i is PS (i), and the item corresponding to the index i until the period t ^{S PS (i)} the minimum ^shipments, when ^t, period cumulative amount of material, step i until t ^{y i, t} is the time period t minimum shipments of items corresponding to the index i to ^{S PS (i ), T} or more, the accumulated processing amount y ^{i, t} of the item / process i up to the period t must satisfy the following formula (5).

[Restriction condition 3: Restriction of shipping requirement]
In order to secure the requested shipping amount, if μ (k, t) is the requested shipping amount for the destination k up to the period t, and N (k) is the set of items and process indexes in the process immediately before shipping where the destination is k. The accumulated processing amount y ^{i, t} of the item / process i up to the period t must satisfy the following formula (6).

[Restriction condition 4: In-process inventory restriction]
If the item / process corresponding to the index i is the same as the item / process to be processed in the immediately preceding process is P (i), the in-process inventory becomes 0 or more, so the item / process i up to the period t The accumulated processing amount y ^{i, t} must satisfy the following formula (7).

[Restriction condition 5: Processing amount transition restriction]
Cumulative amount y ⁱ of the material and process ^i, since ^t is increased with time, cumulative amount y ⁱ of the material, step i to time ^{t, t} is not satisfied equation (8) shown below I must.

[Constraint 6: Process throughput restriction]
The upper limit value of the processing time in the period t in the process m (total operating time in the period t × the number of products that can be processed simultaneously) is M ^{m, t} , and the time required to process the product of the item / process i in the process m LT _i ^m , and the set of items / process indexes processed in the process m is GM ^m , in order to consider the upper limit value of the product quantity that can be processed in each process, the cumulative processing of the items / process i up to the period t The quantity y ^{i, t} must satisfy the following formula (9).

[Restriction condition 7: Upper and lower limit of processing amount]
In the constraint condition 6, the upper limit value of the processing amount is given from the equipment capacity of each process. However, due to various manufacturing restrictions related to the width, thickness, weight, etc. of each product (described later in [Schedule creation process]), it may not be possible to actually manufacture up to a given upper limit value. Therefore, as shown in the following formula (10), the upper limit value z _max ^{i, t} and the lower limit value z _min ^{i, t} of the processing amount in consideration of various manufacturing constraints are set. The upper limit value z _max ^{i, t} and the lower limit value z _min ^{i, t} are obtained by reading the product information corresponding to each past schedule selected in the process of step S2 from the order receiving DB 6a, and the square error of the information vector composed of the product information Can be calculated by extracting a past schedule in which is less than or equal to a specified value, calculating the maximum value and the minimum value of the processing amount of the target item for the extracted past schedule, and multiplying the calculated maximum value and minimum value by a coefficient. The information vector includes information on the total weight value of each item order quantity included in the specified width and thickness range, and the total weight value of each item order quantity whose delivery date is before the specified time. . The processing amount upper and lower limit constraints may be calculated for all items, or may be calculated by selecting some items.

In the process of step S4, the item processing amount calculation device 7 uses the linear regression equation obtained by the process of step S3 to calculate the accumulated processing amount y ^{i, t} of the item / step i in each period t within the planning target period. calculated, cumulative amount of material, process i in the period t-1 ^{y i,} cumulative amount of material, process i at ^t-1 and time t ^{y i,} a difference value between ^{t (y i,} t -y ^{i , T−1} ), the processing amount of the item / process i in the period t within the planning target period is calculated. Then, the item processing amount calculation device 7 stores the data regarding the calculated processing amount for each item / process i and period t in the all process plan information DB 6d as item processing amount information shown in FIG. Thereby, the process of step S4 is completed, and a series of item throughput calculation processing ends.

Next, a method for calculating the coefficient of the linear regression equation when the objective variable of the linear regression equation is the processing amount for each period will be described. When the objective variable of the linear regression equation is the processing amount for each period, the item processing amount calculation device 7 uses the linear regression equation shown in the following equation (11). Here, in Equation (11), z ^{i, t} is the processing amount of the item / process i in the period t, x is an explanatory variable, and a is a parameter related to the explanatory variable x. Then, the item processing amount calculation device 7 calculates the difference between the value on the left side and the value on the right side when the values obtained from the past work schedule are substituted for the explanatory variable x and the objective variable z ^{i, t} (the following formula (12)) is used as an error value, and the coefficient of the linear regression equation is determined so as to minimize the square sum of the error value. That is, the item throughput calculation device 7 determines the coefficient of the linear regression equation so as to minimize the value of the following equation (13). When the objective variable of the linear regression equation is a processing amount for each period, the same processing as that in the case where the objective variable of the linear regression equation is the cumulative processing amount is performed in steps S1 to S3 except for the difference in the linear regression equation. . In the process of step S4, the item processing amount calculation device 7 calculates the processing amount for each item / process and period by substituting the value of the target data into the explanatory variable of the linear regression equation.

  When the objective variable of the linear regression equation is a processing amount for each period, each constraint condition described when the objective variable of the linear regression equation is a cumulative processing amount is expressed by the following mathematical formulas (14) to (20). It is expressed as follows.

[Restriction condition 1: Order quantity restriction]

[Restriction condition 2: Minimum shipment volume restriction]

[Restriction condition 3: Restriction of shipping requirement]

[Restriction condition 4: In-process inventory restriction]

[Restriction condition 5: Processing amount transition restriction]

[Constraint 6: Process throughput restriction]

[Restriction condition 7: Upper and lower limit of processing amount]

[Schedule creation process]
Next, the operation of the production distribution schedule creation system 1 when executing the schedule creation process will be described with reference to the flowchart shown in FIG.

  FIG. 10 is a flowchart showing the flow of schedule creation processing according to an embodiment of the present invention. The flowchart shown in FIG. 10 is started every predetermined control cycle, and the cold pressure equipment management system 2, the annealing equipment management system 3, the plating equipment management system 4, and the shipping equipment management system 5 perform the following schedule creation processing in order. Run.

  In the process of step S11, each management system reads the work schedule and item throughput information of the previous process from the process plan DB 6c and the total process plan information DB 6d, respectively, and refers to the item throughput information and the work schedule of the previous process. Then, the order information of the steel products to be planned is extracted from the order DB 6a. Thereby, the process of step S11 is completed, and the schedule creation process proceeds to the process of step S12.

  In the process of step S12, each management system reads data relating to the constraint condition and evaluation index stored in the process plan DB 6c, and performs mathematical programming (linear programming, nonlinear programming, integer programming, etc.) and heuristics. The work schedule of the steel product from which the order information is read out by the process of step S11 is created so that the evaluation index is improved within a range that satisfies the constraint conditions using tics or the like.

  Here, there may be restrictions on the processing order for products of the same lot type. Specifically, when the facility is a cold rolling facility, as shown in FIG. 11, the width constraint regarding the difference in the width of the products processed continuously, the thickness related to the thickness of the products processed continuously There is a lot product length constraint on the length of a product that can be processed continuously in one lot. For example, the width restriction of the lot type A1 shown in FIG. 11 means that the following restrictions (1) and (2) exist in two consecutive products.

(1) The width of the following product must be less than or equal to the width of the preceding product.
(2) The width of the following product must not be smaller than 11 than the width of the preceding product.

  Therefore, each management system creates a schedule that complies with the constraint conditions. For example, in the schedule that observes the width constraint of the lot type A1 shown in FIG. 11, the width of the product processed later is narrower, but the processing order is set so that the width does not suddenly narrow as it exceeds 11. Is set.

  Depending on the specifications of the ordered product, the lot becomes larger or smaller, and the processing amount also changes. In the above-mentioned item processing amount calculation processing, the above-mentioned detailed constraint conditions are taken into account for a large-scale target, and the calculation time becomes enormous. Therefore, a past work schedule in a situation similar to the current plan target is extracted from the process plan DB 6c. Thus, the shortage of information on the constraint condition is compensated for by reflecting it in the processing amount. Thereby, the accuracy of the processing amount calculated by the item processing amount calculation processing is improved, and the work schedule created by the processing of step S12 becomes efficient.

  In addition, when the order quantity of steel products is insufficient when creating a work schedule, each management system may include steel products of other items as targets for creating the work schedule. In addition, when the processing amount of an item given due to manufacturing constraints or the like cannot be observed, the management system may change the processing amount for each item. Thereby, the process of step S12 is completed and the schedule creation process proceeds to the process of step S13.

  In the process of step S13, each management system stores the work schedule created by the process of step S12 in the process plan DB 6c. Thereby, the process of step S13 is completed and a series of schedule creation processes are complete | finished.

  As is clear from the above description, in the production logistics schedule creation system 1 which is an embodiment of the present invention, the item throughput calculation device 7 sets the process through which the product passes and the type of lot in which the product is collected in each process. Based on the amount of processing for each item in each period in the plan creation period, each management system calculates the processing amount for each item in the period in the plan creation period. Create work schedules for each process during the planning period. As a result, it is possible to easily or quickly create or modify a work schedule for all processes without requiring a huge amount of calculation and a lot of time.

[Modification]
In the item processing amount calculation process, the item processing amount may be calculated without using a linear regression equation. FIG. 12 is a flowchart showing the flow of the item processing amount calculation process when the item processing amount is calculated without using the linear regression equation. Since the processes in steps S21 and S22 are the same as the processes in steps S1 and S2 shown in FIG. 6, the description thereof will be omitted below, and the process in step S23 will be described.

In the processing of step S23, the item processing amount calculation device 7 calculates the processing amount z ^{i, t} in the period t of the item / step i that minimizes the sum of square errors expressed by the following formula (21). . Here, z _k ^{i, t} indicates the processing amount of the item / process i in the period t in the k-th work schedule. The weighting factor w _{k, i, t} can be set using, for example, the following formula (22). In Expression (22), exp indicates an exponential function whose base is e, and pi ^{, 1} ,..., ^{Pi, L} indicate the current planned order quantity for each item size corresponding to the index i (see FIG. 13). P _k ^{i, 1} ,..., P _k ^{i, L} indicate the planned order quantity for each size when the k-th work schedule is created.

  When this square error sum is used, a value close to the processing amount in the work schedule created in a high situation similar to the current order situation is calculated as the current processing amount. The constraint conditions are the same as those in the equations (14) to (20). Under this constraint condition, the amount of processing for each item and each period that minimizes Equation (21) is obtained. Thereafter, each management system generates a work schedule for each process based on the calculated processing amount.

〔Example〕
Finally, an example of numerical calculation performed using the present invention will be described. The target process consists of three stages of equipment: cold rolling equipment, annealing equipment, and shipping equipment. As shown in FIG. 14, there are three types of lots for each of the cold rolling equipment and the annealing equipment, and three shipping destinations. The item throughput was calculated under the following conditions (1) to (4).

(1) Combine the same order of lot types in the passing process and each process as the same item (2) Use linear regression formula to calculate the cumulative processing amount of each item (3) The explanatory variable of the regression formula is the initial variable for each item Inventory (4) period is 12 periods

  FIG. 15 shows a part of the used shipping plan information. FIG. 16 shows the calculation result of the item processing amount calculation process, and shows the product production amount for the port α of the cold rolling equipment in the periods 1 to 6. Since the ship S1 (for the port α) performs loading in an early period, it can be seen that the production amount for the port α is increased in the period 1 to 2 in time. As a result of such adjustments, the average load capacity of the ship exceeded 93% in the final schedule created by the schedule creation process. Moreover, the plan creation time was 1 min or less, and it was confirmed that there was an ability to create a good plan in a short time.

  Although the embodiment to which the invention made by the present inventor is applied has been described above, the present invention is not limited by the description and the drawings that form a part of the disclosure of the present invention according to this embodiment. That is, other embodiments, examples, operational techniques, and the like made by those skilled in the art based on the present embodiment are all included in the scope of the present invention.

1 Production logistics schedule creation system 2 Cold pressure equipment management system 3 Annealing equipment management system 4 Plating equipment management system 5 Shipping equipment management system 6 DB server 6a Order DB
6b Production / Logistics Progress DB
6c Process DB
6d All process plan information DB
7 Item processing amount calculation device

Claims (8)

A production logistics schedule creation system for creating a work schedule of a production logistics process including a plurality of processes each of which executes processing with a lot in which one or more products are collected as a processing unit,
A storage means for storing at least information on the process through which the product passes, the type of lot in which the product is collected in each process, the delivery date of the product, and the past work schedule of each process;
Based on the information stored in the storage means, the product is classified into a plurality of items based on the process through which the product passes and the type of lot in which the product is collected in each step, and the items in each period within the plan creation period Item throughput calculation means for calculating the throughput for each;
A work schedule creation means for creating a work schedule for each process in the plan creation period based on the processing amount for each item in each period within the plan creation period calculated by the item throughput calculation means ;
The item processing amount calculation means inputs at least one or more of initial stock quantity, order quantity, and shipping quantity of each item using information on past work schedules of each process stored in the storage means. Deriving an input / output relational expression that outputs the cumulative processing amount or processing amount for each item in each period within the plan creation period as an output item, and using the derived input / output relational expression, A production logistics schedule creation system that calculates a processing amount for each item in a period . The item throughput calculation means calculates an evaluation value of a past work schedule, and derives the input / output relational expression using information on a past schedule in which the calculated evaluation value is a predetermined value or more. The production distribution schedule creation system according to claim 1 . The item processing amount calculation means uses the information of the past schedule in which the evaluation value is equal to or greater than a predetermined value, and inputs at least one of the initial inventory amount, the order amount, and the shipment amount of each item as a plan item. 3. A linear regression equation having an output item of an accumulated processing amount or processing amount for each item in each period within a creation period is derived, and the derived linear regression equation is used as the input / output relational expression. Production logistics schedule creation system described in 1. The item throughput calculation means calculates an evaluation value of a past work schedule, and based on past schedule information in which the calculated evaluation value is a predetermined value or more, at least a maximum value and a minimum value of a throughput for each item 4. The production logistics schedule creation system according to claim 2 or 3 , wherein one or more are determined and an input / output relational expression is derived using these as constraints. A production logistics schedule creation system for creating a work schedule of a production logistics process including a plurality of processes each of which executes processing with a lot in which one or more products are collected as a processing unit,
A storage means for storing at least information on the process through which the product passes, the type of lot in which the product is collected in each process, the delivery date of the product, and the past work schedule of each process;
Based on the information stored in the storage means, the product is classified into a plurality of items based on the process through which the product passes and the type of lot in which the product is collected in each step, and the items in each period within the plan creation period Item throughput calculation means for calculating the throughput for each;
A work schedule creation means for creating a work schedule for each process in the plan creation period based on the processing amount for each item in each period within the plan creation period calculated by the item throughput calculation means;
The item processing amount calculation means calculates an evaluation value of a past work schedule, extracts past schedule information whose calculated evaluation value is equal to or greater than a predetermined value, and minimizes a processing amount error with the extracted data. A production logistics schedule creation system characterized by calculating the processing amount for each item. The item processing amount calculation means calculates an evaluation value of a past work schedule, extracts past schedule information whose calculated evaluation value is equal to or greater than a predetermined value, and processes the processing amount for each item based on the extracted information Determine at least one of the maximum value and the minimum value for each item and calculate the processing amount for each item so that the processing amount error with the extracted data is minimized with the maximum value and the minimum value of the processing amount for each item as constraints. The production distribution schedule creation system according to claim 5 , wherein: A production logistics schedule creation method for creating a work schedule of a production logistics process including a plurality of processes each of which executes processing by using a lot in which one or more products are collected as a processing unit,
Item throughput calculation step for classifying products into a plurality of items based on the process through which the products pass and the types of lots in which the products are collected in each process, and calculating the throughput for each item in each period within the planning period; ,
A work schedule creation step for creating a work schedule for each process in the plan creation period based on the processing amount of each item in each period within the plan creation period,
The item processing amount calculation step uses information on the past work schedule of each process, and inputs at least one of the initial inventory amount, the order amount, and the shipping amount of each item as an input item. Deriving an input / output relational expression using the accumulated processing amount or processing amount for each item in each period as an output item, and using the derived input / output relational expression, calculate the processing amount for each item in each period within the planning period. A production logistics schedule creation method comprising the step of calculating . A production logistics schedule creation method for creating a work schedule of a production logistics process including a plurality of processes each of which executes processing by using a lot in which one or more products are collected as a processing unit,
Item throughput calculation step for classifying products into a plurality of items based on the process through which the products pass and the types of lots in which the products are collected in each process, and calculating the throughput for each item in each period within the planning period; ,
A work schedule creation step for creating a work schedule for each process in the plan creation period based on the processing amount of each item in each period within the plan creation period,
In the item processing amount calculation step, an evaluation value of a past work schedule is calculated, information of a past schedule whose calculated evaluation value is equal to or greater than a predetermined value is extracted, and a processing amount error with the extracted data is minimized. As described above, a production logistics schedule creation method comprising a step of calculating a processing amount for each item.

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