This case relates to a storage medium, a work plan specifying method, and an information processing device.
A technique is disclosed for optimizing objective functions such as a production cost or a production completion time when an input order of products to a production line is optimized (for example, refer to Patent Documents 1 and 2).
Patent Document 1: Japanese Laid-open Patent Publication No. 2005-092827, Patent Document 2: Japanese Laid-open Patent Publication No. 2019-175488.
According to an aspect of the embodiments, a non-transitory computer-readable storage medium storing a work plan specifying program that causes at least one computer to execute a process, the process includes specifying a certain order under conditions that, in a work line that includes a cutting device and a working device and generates a plurality of objects in the certain order, a certain amount of a material is partially cut by the cutting device from a raw material for each of the plurality of objects, the cut material is processed by the working device, the raw material is switched to a next raw material when the raw material lacks in the cutting device, settings for one selected from the cutting device and the working device are determined for each of the plurality of objects, and a changeover is performed to change the settings of one selected from the cutting device and the working device when the settings are changed; and optimizing an objective function that reflects the changeover and an excess amount of each raw material that are determined according to an input order of the plurality of objects to the work line.
The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention.
In a production line, it is required to use up materials used for products. In order to use up materials, a planning method has been known that solves combinatorial optimization problems such as a cutting stock problem or a bin packing problem. However, if a product input order is switched in order to reduce an excess amount of materials, the number of changeovers in the production line increases, and there is a possibility that an objective function reflecting the changeover is deteriorated.
In one aspect, an object of the present invention is to provide an information processing device, a work plan specifying method, and a work plan specifying program that can improve an objective function reflecting a changeover while suppressing an excess material amount.
It is possible to improve an objective function reflecting a changeover while suppressing an excess material amount.
In a production line, it is required to use up materials used for products without waste. In order to use up materials, a planning method has been known that solves combinatorial optimization problems such as a cutting stock problem or a bin packing problem.
Furthermore, it is also required to shorten a production completion time to meet a delivery deadline. In a case where the production completion time is shortened in order to meet the delivery deadline, a planning method is known for reflecting a processing time of each device in a production process, the number of works in progress, or the like in a scheduler or a line simulator and performing optimization by an algorithm.
In
Product type information represents settings of at least one of the cutting device and the processing device. For example, a type of a saw of the cutting device is changed according to a product type. Alternatively, a processing method of the processing device is changed according to the product type. Therefore, since it is needed to change the settings of at least one of the cutting device and the processing device when the product type information changes, a changeover is needed. In the example in
Furthermore, in
In the upper part of
In order to reduce these excess material amounts as possible, it is sufficient to change a combination of products using the respective raw materials.
However, in the example in
Therefore, in the following embodiments, an information processing device, a work plan specifying method, and a work plan specifying program that can improve an objective function reflecting a changeover while suppressing an excess material amount will be described.
The production line model storage unit 10 stores a production line model.
A plurality of products is input to the “start” cell one by one according to an input order. In each cell, the product stays until a processing time uniquely set to the product has elapsed. When the processing time elapses, if there is no product in a next moving destination cell, the product moves to the cell.
The production master 20 stores production order information in which a size of a material to be used and product type information are associated with a product number.
Furthermore, the production master 20 stores raw material information.
Furthermore, the production master 20 stores device information.
Furthermore, the production master 20 stores a changeover condition in a case where a changeover for switching raw materials is performed.
Furthermore, the production master 20 stores a changeover condition in a case where a changeover for switching product types is performed.
Next, processing of the information processing device 100 will be described with reference to the flowchart in
Next, the simulator 40 performs a line simulation in a case where products are input to the production line one by one according to the initial input order (step S2).
First, the simulator 40 arranges the products in the “start” cell one by one according to the initial input order. In the “material determination” cell, a material size of the product arriving at the “material determination” cell is sequentially subtracted from a raw material size of the raw material information. Thereby, a remaining amount of the raw material is calculated. If the subtracted result is positive, a processing time in the “material determination” cell is “1”. Therefore, the product stays at the material determination cell for only a time corresponding to the processing time “1”, and the product moves to the next cell if no product stays in the next cell. If the subtracted result is negative, since a changeover of the raw material occurs, the processing time in the “material determination” cell is “100”. Therefore, the product stays at the material determination cell for only a time corresponding to the processing time “100”, and the product moves to the next cell if no product stays in the next cell. A raw material remaining amount immediately before the subtracted result becomes negative is the excess material amount of the raw material. In this case, the material size of the product is subtracted from a new raw material size.
In the “cutting device” cell, the product that has arrived at the “cutting device” cell stays for only a time corresponding to the processing time “50”. Furthermore, in the “cutting device” cell, it is determined whether or not product type information of the product that has arrived at the “cutting device” cell is different from product type information of a previous product that has arrived. If the product type information of the product that has arrived at the “cutting device” cell is different from the product type information of the previous product that has arrived, a changeover occurs. If the changeover has occurred, the product further stays at the “cutting device” cell for only a time corresponding to the processing time “100”, and then, moves to the next cell.
In the “processing device” cell, the product that has arrived at the “processing device” cell stays for only a time corresponding to the processing time “150” and moves to the next cell.
Next, the determination unit 60 evaluates a key performance indicator (KPI) for the result of the line simulation performed in step S2 (step S3). In step S3, the determination unit 60 calculates an excess material amount and a production completion time for the line simulation result. The excess material amount is a total value of raw material remaining amounts of respective raw materials that have been used. The production completion time is a time from when a first product is input to start to when a final product arrives at a production completion cell.
Next, the determination unit 60 determines whether or not the excess material amount and the production completion time calculated in step S3 satisfy an end condition (step S4). For example, the determination unit 60 determines whether or not the excess material amount is equal to or less than a threshold and the production completion time is equal to or less than a threshold.
In a case where it is determined as “Yes” in step S4, the execution of the flowchart ends. In a case where it is determined as “No” in step S4, the input order switch unit 50 selects an input order candidate for the input order that is a target of the line simulation in step S2 (step S5). Next, the input order switch unit 50 executes a process called intersection for selecting an input order candidate whose result is improved based on the result of the line simulation obtained based on the input order to be subjected to the line simulation in step S2 and the result of the line simulation obtained from the input order candidates selected in step S5 (step S6). Next, the input order switch unit 50 generates an input order by mutating the result of step S6 (step S7). Thereafter, the process from step S2 is executed again. In this case, in step S2, a line simulation is performed for the input order generated in step S7.
(Simulation Result)
Subsequently, a result of an actual simulation will be described. As illustrated in
As illustrated in
According to the present embodiment, it is possible to suppress the excess material amount by switching the input order of each product to the production line and performing optimization, and an objective function reflecting the changeover caused by switching the input order is optimized. As a result, it is possible to improve the objective function reflecting the changeover while suppressing the excess material amount.
Note that as the method for switching the input order, an evolutionary algorithm and a local search method may be used. These algorithms can also be used for multi-objective optimization. The evolutionary algorithms include an evolutionary strategy algorithm, a genetic algorithm, or the like. The local search methods include an annealing method or the like.
Although the production completion time is used as the objective function in the first embodiment, the present invention is not limited to this. In a second embodiment, a case will be described where a power consumption amount and a cost caused by a changeover are used as objective functions.
Subsequently, a line simulation in the second embodiment will be described. A “start” cell performs an operation as in the first embodiment. In a “material determination” cell, a material size of the product arriving at the “material determination” cell is sequentially subtracted from a raw material size of the raw material information. Thereby, a remaining amount of the raw material is calculated. If the subtracted result is positive, a processing time in the “material determination” cell is “1”, the power consumption is “1”, and the cost is “1”. Therefore, the product stays at the material determination cell for only a time corresponding to the processing time “1”, and the product moves to the next cell if no product stays in the next cell. Furthermore, the power consumption “1” and the cost “1” are added to the product. If the subtracted result is negative, since the changeover of the raw material occurs, the processing time in the “material determination” cell is “100”, the power consumption is “50”, and the cost is “50”. Therefore, the product stays at the material determination cell for only a time corresponding to the processing time “100”, and the product moves to the next cell if no product stays in the next cell. A raw material remaining amount immediately before the subtracted result becomes negative is the excess material amount of the raw material. In this case, the material size of the product is subtracted from a new raw material size.
In a “cutting device” cell, a product that has arrived at the “cutting device” cell stays for only a time corresponding to the processing time “50”, power consumption “400” and a cost “300” are added to the product. Furthermore, in the “cutting device” cell, it is determined whether or not product type information of the product that has arrived at the “cutting device” cell is different from product type information of a previous product that has arrived. If the product type information of the product that has arrived at the “cutting device” cell is different from the product type information of the previous product that has arrived, a changeover occurs. If the changeover has occurred, the product further stays at the “cutting device” cell for only a time corresponding to the processing time “100”, and then, moves to the next cell.
In the “processing device” cell, the product that has arrived at the “processing device” cell stays for only a time corresponding to the processing time “150” and moves to the next cell.
In the present embodiment, in step S3 in the flowchart in
According to the present embodiment, in addition to the production completion time, the power consumption, the cost, or the like caused by the changeover can be optimized. Note that, in addition to the production completion time, the power consumption, the cost, or the like, the number of changeovers or the like may be included in the objective function.
(Hardware Configuration)
The central processing unit (CPU) 101 is a central processing unit. The CPU 101 includes one or more cores. The random access memory (RAM) 102 is a volatile memory that temporarily stores a program to be executed by the CPU 101, data to be processed by the CPU 101, or the like. The storage device 103 is a nonvolatile storage device. For example, a read only memory (ROM), a solid state drive (SSD) such as a flash memory, a hard disk to be driven by a hard disk drive, or the like may be used as the storage device 103. The storage device 103 stores a work plan specifying program. The interface 104 is an interface device with an external device. Each unit of the information processing device 100 is implemented by executing the work plan specifying program by the CPU 101. Note that hardware such as a dedicated circuit may be used as each unit of the information processing device 100.
In each example described above, the production line is an example of a work line for a plurality of objects according to a predetermined order. A plurality of products input to the production line is an example of the plurality of objects. The processing device is an example of a working device that performs a work on the plurality of objects. The input order switch unit and the determination unit 60 are examples of an optimization execution unit that optimizes the objective function reflecting the changeover and the excess amount of each raw material determined according to the input order of the plurality of objects to the work line.
While the embodiments of the present invention have been described above in detail, the present invention is not limited to such specific embodiments, and various modifications and alterations may be made within the scope of the present invention described in the claims.
All examples and conditional language provided herein are intended for the pedagogical purposes of aiding the reader in understanding the invention and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although one or more embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.
This application is a continuation application of International Application PCT/JP2020/027259 filed on Jul. 13, 2020 and designated the U.S., the entire contents of which are incorporated herein by reference.
Number | Date | Country | |
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Parent | PCT/JP2020/027259 | Jul 2020 | US |
Child | 18060020 | US |