JP6927111B2 - Inventory amount transition simulation method and inventory amount transition simulation device - Google Patents

Description

The present invention relates to an inventory amount transition simulation method and an inventory amount transition simulation device.

In factories where intermediate products or materials pass through multiple production lines and transfer lines and a wide variety of products are manufactured, the efficiency of the production lines and transfer lines and the capacity of the storage space in front of the lines are taken into consideration. In such a factory, it is necessary to avoid a situation in which the inventory of intermediate products accumulates in the middle of the production line or the transport line, or the inventory amount of intermediate products in the storage area exceeds the capacity. Therefore, it is required to perform a simulation to grasp whether or not the above-mentioned situation can occur from the daily or hourly input amount of the intermediate product or material to the factory.

However, since the distribution in the factory is complicated, the work is complicated by the manual calculation, and it is difficult to verify it frequently. Therefore, technologies and programs have been developed that virtually reproduce and simulate the physical distribution in the factory using a computer.

For example, there is known a discrete simulator in which a transport rule for each product is determined, time steps are sequentially advanced, and the movement of the product is simulated according to the previous transport rule. However, in such a discrete simulator, for example, it is necessary for a person to decide in detail the transportation rules such as whether to give priority to the product to be sent to the next production line for each situation, and the target distribution becomes large-scale and complicated. The more difficult it is to determine the rules and adjust the parameters within the rules. As a result, development may be impossible or protracted.

For example, in Patent Document 1, a simulation result can be obtained by creating a route model using Petri nets and solving state transitions by optimization calculation. However, since it becomes an optimization problem including discrete variables because the movement of individual products is taken into consideration, in the case of a large-scale factory containing multiple lines, the calculation time increases exponentially and within a practical time. There is a risk that the problem cannot be solved.

Japanese Patent No. 4987602

The present invention has been made in view of the above circumstances with respect to a simulation method in which a plurality of production lines and transfer lines are provided and a simulation method for predicting a transition of the inventory amount of intermediate products in a storage place provided for these lines is provided. Is. More specifically, the object of the present invention made in view of the above-mentioned problems is that it is not necessary to determine in detail the transportation rules for each situation even for large-scale and complicated physical distribution, and for each product type. It is an object of the present invention to provide an inventory amount transition simulation method and an inventory amount transition simulation device that can predict the transition of the inventory amount of the above in a practical calculation time.

In order to solve the above problem, the inventory amount transition simulation method according to the embodiment of the present invention is used.
This is an inventory quantity transition simulation method that predicts the transition of the inventory quantity of intermediate products in the storage area provided for the production line and the transport line.
A step of inputting input information including information on the amount of the intermediate product and route information between the storage areas through which the intermediate product can pass.
A step of creating a mathematical model including a constraint expression and an evaluation function based on the input information, and
Based on the created mathematical model, the step of outputting the transition of the inventory amount of the intermediate product in the storage place and
Including
Information on the quantity of the intermediate product is treated as a continuous quantity based on the weight of the intermediate product aggregated for each product type.

The inventory amount transition simulation device according to the embodiment of the present invention is
It is an inventory quantity transition simulation device that predicts the transition of the inventory quantity of intermediate products in the storage space provided for the production line and the transport line.
An input unit that accepts input of input information including information on the amount of the intermediate product and route information between the storage places through which the intermediate product can pass.
A processing unit that creates a mathematical model including constraint expressions and evaluation functions based on the input information, and
Based on the created mathematical model, an output unit that outputs the transition of the inventory amount of the intermediate product in the storage place, and
With
Information on the quantity of the intermediate product is treated as a continuous quantity based on the weight of the intermediate product aggregated for each product type.

According to the inventory amount transition simulation method and the inventory amount transition simulation device according to the embodiment of the present invention, it is not necessary to determine in detail the transportation rules and the like for each situation even for large-scale and complicated physical distribution, and for each product type. It is possible to predict the transition of the inventory amount of the product in a practical calculation time.

It is a schematic diagram which showed an example of the layout of the factory which verifies the physical distribution by the inventory amount transition simulation method which concerns on one Embodiment. It is a flowchart of the inventory amount transition simulation method which concerns on one Embodiment. It is a block diagram which shows the structure of the inventory amount transition simulation apparatus which concerns on one Embodiment. It is a figure which shows the transition of the occupancy rate of the storage place A. It is a figure which shows the transition of the occupancy rate of the storage place B. It is a figure which shows the transition of the occupancy rate of the storage place C. It is a figure which shows the transition of the occupancy rate of the storage place D. It is a figure which shows the transition of the occupancy rate of the storage place E. It is a figure which shows the transition of the occupancy rate of the storage place F. It is a figure which shows the transition of the occupancy rate of the storage place G. It is a figure which shows the transition of the occupancy rate of the storage place H. It is a figure which shows the transition of the occupancy rate of the storage place I. It is a figure which shows the transition of the occupancy rate of the storage place J. It is a figure which shows the transition of the occupancy rate of the storage place K.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

(First Embodiment)
FIG. 1 is a schematic diagram showing an example of a factory layout for verifying physical distribution by the inventory amount transition simulation method according to the embodiment.

For example, in a factory having the layout shown in FIG. 1, four production lines MA1, MA2, MA3, and MA4 and six transfer lines C1, C2, C3, C4, C5, and C6 are provided. Each of the production lines MA1 to MA4 includes any production equipment required for steelmaking, such as cold rolling equipment, annealing equipment, surface treatment equipment, inspection equipment, and packing equipment. Each of the transport lines C1 to C6 includes any transport equipment such as a crane, a conveyor, and a trolley.

For example, in the factory having the layout shown in FIG. 1, six storage areas Y1, Y2, Y3, Y4, Y5, and Y6 are provided for the production lines MA1 to MA4 and the transfer lines C1 to C6.

In FIG. 1, the intermediate products are transported while being processed from left to right. For example, the intermediate product arranged in the storage place Y1 passes through the transport line C2 and is put into the production line MA2. After that, the intermediate product put into the production line MA2 is processed by the production line MA2, passes through the transfer line C6 from the production line MA2, and is carried out to the storage place Y5. For example, the intermediate product arranged in the storage place Y1 passes through the transport line C1 and is put into the production line MA1. After that, the intermediate product put into the production line MA1 is processed by the production line MA1, passes through the transfer line C3 or C4 from the production line MA1, and is carried out to the storage place Y3. The same description applies to the other routes shown in FIG.

FIG. 2 is a flowchart of the inventory amount transition simulation method according to the embodiment. FIG. 3 is a block diagram showing a configuration of the inventory amount transition simulation device 10 according to the embodiment. The inventory amount transition simulation device 10 includes an input unit 11, a processing unit 12, and an output unit 13. Hereinafter, the inventory amount transition simulation method and the inventory amount transition simulation apparatus 10 according to the first embodiment will be described in detail with reference to FIGS. 2 and 3.

The input unit 11 includes an arbitrary input interface that accepts user operations. The input interface includes, for example, a pointing device such as a mouse, a physical key, a touch panel, and the like.

The processing unit 12 includes one or more processors. The processing unit 12 controls the operation of the entire inventory amount transition simulation device 10.

The output unit 13 includes an arbitrary display device. Display devices include, for example, liquid crystal displays and the like. The output unit 13 displays the information acquired from the processing unit 12 as needed.

In step S101, input information including information on the quantity of the intermediate product and route information between each storage place through which the intermediate product can pass is input. At this time, the input unit 11 of the inventory amount transition simulation device 10 accepts the input of these input information.

Information on the quantity of intermediate products is treated as a continuous quantity based on the weight of the intermediate products aggregated for each variety. The variety is determined based on, for example, the characteristics of the material of the intermediate product and the destination of the intermediate product. For example, one type is a coil for steel plates of automobiles, and the other type is a coil for stainless steel materials of edible cans. The type means, for example, ordinary steel or stainless steel in the cold rolling process of steelmaking. Different varieties have different production lines that go through before shipping.

The information regarding the quantity of the intermediate product includes, for example, the stock quantity of the intermediate product at each storage place when the inventory quantity transition simulation is started. Information on the amount of intermediate products includes, for example, the amount of intermediate products input from the outside to each storage area. Information on the quantity of intermediate products includes, for example, the capacity of each storage area. Information about the quantity of intermediate products includes, for example, the processable quantity of each of the production line and the transport line.

Each of Tables 1 to 7 below is a table summarizing the input information input in step S101. The input information input in step S101 will be described in detail with reference to Tables 1 to 7.

Table 1 is a table summarizing the route information between each storage place through which the intermediate product can pass among the input information input in step S101 for each product type. The route information shown in Table 1 is based on the layout of the factory shown in FIG.

For example, the variety 1 is transported from the storage place Y1 through the storage places Y3 and Y4 to the storage place Y5. Alternatively, it is transported from the storage place Y1 through the storage places Y6 and Y4 to the storage place Y5. For example, the variety 2 is transported from the storage place Y1 to the storage place Y5. For example, the variety 3 is transported from the storage place Y2 to the storage place Y5 through the storage places Y3 and Y4. For example, the variety 4 is transported from the storage place Y1 through the storage place Y3 to the storage place Y5. For example, the variety 5 is transported from the storage place Y2 through the storage place Y3 to the storage place Y5.

Table 2 is a table summarizing the production lines and transport lines provided on the routes between the storage sites shown in Table 1. The information about the production line and the transport line shown in Table 2 is based on the layout of the factory shown in FIG.

For example, a transfer line C1, a production line MA1, a transfer line C3, and a transfer line C4 are provided between the storage place Y1 and the storage place Y3. A transfer line C1, a production line MA1, and a transfer line C3 are provided between the storage place Y1 and the storage place Y6. A transport line C4 is provided between the storage place Y6 and the storage place Y4. A transport line C2 is provided between the storage place Y2 and the storage place Y3. A transport line C2, a production line MA2, and a transport line C6 are provided between the storage place Y1 and the storage place Y5. A transport line C4 is provided between the storage place Y3 and the storage place Y4. A transfer line C4, a transfer line C5, a production line MA4, and a transfer line C6 are provided between the storage place Y3 and the storage place Y5. A transfer line C5, a production line MA3, and a transfer line C6 are provided between the storage place Y4 and the storage place Y5.

Table 3 is a table summarizing the transport lines provided in parallel on one route between each storage place. The information about the transport lines shown in Table 3 is based on the factory layout shown in FIG.

For example, a transport line C3 and a transport line C4 are provided in parallel between the storage place Y1 and the storage place Y3. For example, a transfer line C4 and a transfer line C5 are provided in parallel between the storage area Y3 and the storage area Y5.

Each of Tables 4 to 7 is a table summarizing the information regarding the quantity of the intermediate product among the input information.

Table 4 is a table showing the amount that can be processed per unit time of each of the production lines MA1 to MA4 and the transfer lines C1 to C6.

As shown in Table 4, in step S101, the input unit 11 appropriately receives the input of the processable amount per unit time of each of the production lines MA1 to MA4 and the transfer lines C1 to C6. The processable amount of each line is treated as a continuous amount in tons based on the weight of the intermediate products aggregated for each product type.

Table 5 is a table showing the capacities of the storage areas Y1 to Y6, respectively.

As shown in Table 5, in step S101, the input unit 11 appropriately receives the input of the capacities of the storage areas Y1 to Y6. The capacity of each storage area is treated as a continuous quantity in tons based on the weight of the intermediate products aggregated for each variety.

Table 6 is a table showing the inventory amount of intermediate products for each product type at each storage place when the inventory amount transition simulation is started. As an example, the inventory amount shown in Table 6 is based on the route information shown in Table 1. More specifically, for each storage, only varieties that may pass based on the routes shown in Table 1 are considered as inventory.

As shown in Table 6, in step S101, the input unit 11 appropriately accepts the input of the inventory amount of the intermediate product at each storage place when starting the inventory amount transition simulation for each product type. The inventory amount is treated as a continuous amount in tons based on the weight of the intermediate products aggregated for each product type.

Table 7 is a table exemplifying the input amount of the intermediate product from the outside to each storage place for each variety. As an example, the input amount shown in Table 7 is based on the route information shown in Table 1. More specifically, for each storage site, only varieties that may pass based on the routes shown in Table 1 are considered as input amounts. In Table 7, as an example, it is assumed that only the storage areas Y1 and Y2 accept intermediate products from the outside. In Table 7, as an example, it is assumed that intermediate products are introduced from the outside at three different times.

As shown in Table 7, in step S101, the input unit 11 appropriately accepts the input of the input amount of the intermediate product to each storage place for each product type. The input amount is treated as a continuous amount in tons based on the weight of the intermediate products aggregated for each product type.

In step S102 of FIG. 2, a mathematical model including a constraint expression and an evaluation function based on the input information input in step S101 is created. At this time, the processing unit 12 of the inventory amount transition simulation device 10 creates the mathematical model. The mathematical model will be described in detail below.

The stock amount of the variety k of the storage place y at the time t is q _ykt , the input amount of the variety k from the outside to the storage place y at the time t is _Lykt , and each storage place indicated by the route information p (hereinafter referred to as a path) of the variety k. Let the flow amount at the time t between them be flow _pkt , the set of paths input to _{the storage place y be IN y} , and the set of paths output from the storage place y be OUT _y . At this time, the transition of the inventory amount for each variety k of the storage place y is expressed by the formula (1-1).

Equation (1-1) is the first constraint equation representing that the time-varying amount of the inventory amount is the sum of the input amount from the outside and the transport amount between each storage place. The first constraint formula represents that the amount of the intermediate product that flows when the intermediate product moves between each storage place is stored for each product type as a constraint on the total amount of transportation between each storage place for each product type.

・・・式（１−２） Each variety does not take any route other than those shown in Table 1. The constraint that the transport amount on the impossible route is zero is expressed by the equation (1-2), _{where the possible route set of the product type k is Path k.}

... Equation (1-2)

When the inventory amount transition simulation is started, that is, when the inventory amount of the variety k in the storage place y at t = 0 is Q _yk , the initial state of the inventory amount is expressed by the equation (2).

Assuming that the capacity of the storage place y is QC _y , it is necessary that the equation (3) holds.

Equation (3) is a second constraint equation indicating that the total amount of inventory over all varieties is equal to or less than the capacity of the storage area. The second constraint formula represents that the inventory amount over all varieties cannot exceed the capacity of the storage place as a constraint on the total transportation amount of all varieties.

The line m including the production line and the transport line provided on the path p u _mpkt the amount of processing the product type k at time t, the set of paths for which the line m is responsible for transport is P _m , and the line m provided on the pass p. _{Let PALA mp} be the set of other lines m'parallel to. The PALA _mp uses another transport line capable of transporting instead of one transport line, such as a transport line C4 provided in parallel with the transport line C3 between the storage sites Y1 and the storage site Y3 in FIG. include. At this time, the relationship between the transport amount flow _pkt between each storage place and the processing amount u _mpkt on the line m is expressed by the equation (4).

Assuming that the processable amount of _{the line m is U m} , the fact that the line m cannot process more than the processable amount is expressed by the equation (5).

_{Equation (5) is a third constraint equation indicating that the total processing amount over all paths of all varieties and the set P m} is less than or equal to the processing amount when the processing amount of the line m does not change for each type. be.

Logistics is expressed by a mathematical formula by the above equations (1) to (5). In addition, the evaluation function of Eq. (6) is considered to give a policy of how to flow the product.

・・・式（６）

... Equation (6)

Here, the set of production lines in the line m is set to MA, and the weighting coefficient applied to _{the processing amount u mpkt of the line m and the product type k at time t is set to w mkt} . As shown in the formula (6), the evaluation function includes the processing amount of the production line. As a policy of how to flow the product, the total processing amount of each production line is maximized by maximizing the evaluation function. The amount of transportation at this time and the amount of processing of each of the production line and the transportation line are determined for each hour. By changing the value of the weighting coefficient, the processing amount balance for each product type on each production line at the specified time is changed. As described above, in the inventory amount transition simulation method according to the first embodiment, it is possible to perform a simulation when the processing amount balance is changed. This makes it possible to grasp which storage area becomes the bottleneck when the processing amount balance is changed.

The above mathematical expressions are mathematical optimization problems and can be solved by linear programming. By using these methods, _{the value of the stock quantity q ykt} of the mathematical model is determined.

In step S103 of FIG. 2, the transition of the inventory amount of the intermediate product in each storage place is output based on the mathematical model created in step S102. At this time, the output unit 13 of the inventory amount transition simulation device 10 outputs such a transition of the inventory amount.

Table 8 is a table showing the transition of the inventory amount of the intermediate products at each output storage place. In Table 8, the transition of the inventory amount is shown for each variety passing through each storage place based on the route information shown in Table 1.

In Table 8, the inventory amount of the intermediate product is output over an arbitrary time step n for each variety passing through each storage place. As a result, it is possible to grasp the transition of the inventory amount of intermediate products.

According to the inventory amount transition simulation method and the inventory amount transition simulation device 10 according to the first embodiment as described above, it is not necessary to determine in detail the transportation rules and the like for each situation even for large-scale and complicated physical distribution. , It is possible to predict the transition of inventory amount for each product type in a practical calculation time. More specifically, since the information about the quantity of the intermediate product is treated as a continuous quantity, it can be formulated without using discrete variables, and the problem to be dealt with becomes a linear continuous variable optimization problem. This reduces the calculation time.

According to the inventory amount transition simulation method and the inventory amount transition simulation device 10 according to the first embodiment, it is possible to investigate which storage space is full in the distribution by the current production line and transfer line. Therefore, it is possible to grasp the storage place that becomes a bottleneck in physical distribution. By doing this, it is possible to understand how much additional capacity is required for the storage area that is a bottleneck when the physical distribution is changed, or how to establish a new transportation route to other storage areas. can. From the above, it is possible to suppress the possibility that, for example, an intermediate product to be processed on the production line is not transported to the storage place at all, or a situation where one storage place is empty and the other storage place is full. ..

(Example)
Using the above-mentioned inventory amount transition simulation method, an example of product distribution in a factory was verified. Some of the input information used is as follows. The number of varieties handled in the target factory is 40. The number of storage areas is 11. The number of production lines and transfer lines is 30. An inventory change simulation was carried out with a verification period of one month.

4 to 14 are diagrams showing the results of the inventory amount transition simulation carried out. FIG. 4 is a diagram showing a transition of the occupancy rate obtained by dividing the total inventory amount of all varieties in the storage place A by the capacity. Similarly, FIG. 5 is a diagram showing a transition of the occupancy rate of the storage place B. FIG. 6 is a diagram showing a transition of the occupancy rate of the storage place C. FIG. 7 is a diagram showing a transition of the occupancy rate of the storage place D. FIG. 8 is a diagram showing a transition of the occupancy rate of the storage place E. FIG. 9 is a diagram showing a transition of the occupancy rate of the storage space F. FIG. 10 is a diagram showing a transition of the occupancy rate of the storage space G. FIG. 11 is a diagram showing a transition of the occupancy rate of the storage place H. FIG. 12 is a diagram showing a transition of the occupancy rate of the storage place I. FIG. 13 is a diagram showing a transition of the occupancy rate of the storage place J. FIG. 14 is a diagram showing a transition of the occupancy rate of the storage place K.

As shown in FIGS. 5 and 14, respectively, it can be seen that the occupancy rate of the storage place B and the storage place K is 100% most of the time. As described above, the capacities of the storage B and the storage K are insufficient, and these storages may be a bottleneck. Therefore, it is conceivable to increase the capacity of at least one of the storage place B and the storage place K, or to provide a new transportation route to another storage place where the occupancy rate tends to be low. Other storage areas that tend to have a low occupancy rate correspond to, for example, storage areas F and storage areas H shown in FIGS. 9 and 11, respectively. By changing the input information to reflect these measures and then recalculating, the effect of improvement such as the elimination of bottlenecks can be confirmed.

(Second Embodiment)
Hereinafter, the inventory amount transition simulation method and the inventory amount transition simulation device 10 according to the second embodiment will be described. The same reference numerals are used for the same configurations as those in the first embodiment, and the description thereof will be omitted. The points different from the first embodiment will be mainly described.

In the first embodiment, although the process can amount U _m of the production line and transfer line are assumed to be constant regardless of the variety, in the second embodiment, assuming processable quantity is different for each type do. At this time, the following formula (7) is used instead of the formula (5), where the _treatable amount in the line m of the product type k is U mk.

・・・式（７）

... Equation (7)

In the formula (7), when the processable amount of the line m changes for each variety, the sum of all the varieties and the total path of the _{set P m, which is the value obtained by dividing the processable amount for each variety by the processable amount, is 1 or less.} It is a third constraint expression indicating that there is.

According to the inventory amount transition simulation method and the inventory amount transition simulation device 10 according to the second embodiment, the simulation can be performed more accurately according to the actual situation in which the processable amount of the production line and the transport line differs for each product type. It can be carried out.

(Third Embodiment)
Hereinafter, the inventory amount transition simulation method and the inventory amount transition simulation device 10 according to the third embodiment will be described. The same reference numerals are used for the same configurations as those of the first embodiment and the second embodiment, and the description thereof will be omitted. The points different from the first embodiment and the second embodiment will be mainly described.

In the third embodiment, in addition to the restrictions described in the first embodiment or the second embodiment, an operation in which a specific variety is preferentially processed in a certain amount during a certain period is considered. In such an operation, for example, when the setup change time of the production line and the transport line generated by switching the type of the intermediate product to be passed is long, the number of switchings is reduced as much as possible to efficiently process the specific type. Will be implemented. At this time, the following equation (8) is used.

・・・式（８）

... Equation (8)

Here, T _c is a time set within a certain period in which the above-mentioned operation is carried out, and F _ck is a target processing amount. Equation (8) is a fourth constraint equation indicating that the sum of the processing amounts of the specific varieties over a predetermined period and _{the entire path of the set P m} is equal to or more than the target processing amount.

According to the inventory amount transition simulation method and the inventory amount transition simulation device 10 according to the third embodiment, even in the case where the above-mentioned operation is carried out, the simulation is performed more accurately according to the actual situation. be able to.

It will be apparent to those skilled in the art that the present invention can be realized in certain forms other than those described above without departing from its spirit or its essential features. Therefore, the above description is exemplary and is not limited thereto. The scope of the invention is defined by the appended claims, not by the earlier description. It is assumed that some of all changes that are within the same range are included in it.

The functions and the like included in each step of the above-mentioned inventory amount transition simulation method can be rearranged so as not to be logically inconsistent, and a plurality of steps can be combined or divided into one. ..

Although the inventory amount transition simulation method and the inventory amount transition simulation device 10 have been mainly described, the present invention can also be realized as a program executed by the processor included in the processing unit 12 or a storage medium on which the program is recorded. It should be understood that the scope of the present invention also includes these.

The evaluation function has been described as being given by Eq. (6), but the present invention is not limited to this. The evaluation function may be any function that can give a policy on how to distribute the product. For example, the evaluation function may include the shipment amount for each product type to be finally shipped instead of the processing amount for each product type on the production line. In this case, the total shipment volume is maximized by maximizing the evaluation function.

The factory layout shown in FIG. 1, the route information shown in Table 1, and the input information such as the storage place for accepting intermediate products from the outside shown in Table 7 are not limited to the above-mentioned contents. These may be arbitrarily determined according to the actual situation of the factory.

10 Inventory quantity transition simulation device 11 Input unit 12 Processing unit 13 Output unit C1, C2, C3, C4, C5, C6 Transport line MA1, MA2, MA3, MA4 Production line Y1, Y2, Y3, Y4, Y5, Y6 Storage area

Claims (7)

This is an inventory quantity transition simulation method that predicts the transition of the inventory quantity of intermediate products in the storage area provided for the production line and the transport line.
A step of inputting input information including information on the amount of the intermediate product and route information between the storage areas through which the intermediate product can pass.
A step of creating a mathematical model including a constraint expression and an evaluation function based on the input information, and
Based on the created mathematical model, the step of outputting the transition of the inventory amount of the intermediate product in the storage place and
Including
The information regarding the quantity of the intermediate product is treated as a continuous quantity based on the weight of the intermediate product aggregated for each product type, and the inventory quantity of the intermediate product at the storage place when the inventory quantity transition simulation is started and the inventory amount of the intermediate product from the outside are described. Including the amount of the intermediate product input to the storage area,
The constraint formula includes a first constraint formula indicating that the time change amount of the inventory amount is the total of the input amount and the transport amount between the storage places based on the route information .
Inventory amount transition simulation method. Information on the quantity of the intermediate product is available .
The capacity of the storage space and
The amount that can be processed by the production line and the transport line, and
including,
The inventory amount transition simulation method according to claim 1. The constraint expression includes a second constraint that the sum over all varieties of prior SL inventory represents not more than the capacity of the storage,
The inventory amount transition simulation method according to claim 2. The constraint equation further includes a third constraint equation.
The third constraint equation is
When the processable amount does not change for each product type, it means that the total processing amount of the production line and the transport line for all types is equal to or less than the processable amount.
When the treatable amount changes for each variety, it means that the sum of the values obtained by dividing the treatable amount by the treatable amount over all varieties is 1 or less.
The inventory amount transition simulation method according to claim 3. The constraint equation further includes a fourth constraint equation.
The fourth constraint equation represents that the total sum of the treated amounts of the specific variety over a predetermined period is equal to or greater than the target processed amount.
The inventory amount transition simulation method according to claim 4. The evaluation function includes the processing amount of the production line.
In the step of creating the mathematical model, the processing amount of the production line is maximized by maximizing the evaluation function, the transfer amount between the storage areas based on the route information, and the production line and the transfer line. Determine each processing amount for each hour,
The inventory amount transition simulation method according to any one of claims 1 to 5. It is an inventory quantity transition simulation device that predicts the transition of the inventory quantity of intermediate products in the storage space provided for the production line and the transport line.
An input unit that accepts input of input information including information on the amount of the intermediate product and route information between the storage places through which the intermediate product can pass.
A processing unit that creates a mathematical model including constraint expressions and evaluation functions based on the input information, and
Based on the created mathematical model, an output unit that outputs the transition of the inventory amount of the intermediate product in the storage place, and
With
The information regarding the quantity of the intermediate product is treated as a continuous quantity based on the weight of the intermediate product aggregated for each product type, and the inventory quantity of the intermediate product at the storage place when the inventory quantity transition simulation is started and the inventory amount of the intermediate product from the outside are described. Including the amount of the intermediate product input to the storage area,
The constraint formula includes a first constraint formula indicating that the time change amount of the inventory amount is the total of the input amount and the transport amount between the storage places based on the route information .
Inventory amount transition simulation device.

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