Demand control device, demand control method, and computer program

Abstract

To plan a production schedule that improves productivity after performing on-demand control of a range to be an upper limit value or less of use power.SOLUTION: A demand control device includes an acquisition unit for acquiring power demand information related to variation of power demand scheduled to be used by equipment, product information related to the number of products scheduled to be produced and a deliver period, and equipment information related to equipment for performing each step of a job necessary to produce the product, an objective function setting unit for setting an objective function for minimizing an end time of the whole jobs by using the product information and the equipment information, a condition setting unit for setting a constraint condition necessary to solve the objective function by using the power demand information, the product information, and the equipment information, a planning unit for planning a production schedule of the product by solving the objective function after satisfying the constraint condition, and a power calculation unit for calculating use power along a time series in the product schedule planed by the planning unit by using the power demand information.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a demand control device, a demand control method, and a computer program. [Background technology]

[0002] At production sites such as factories, fluctuations in outside temperature can cause the power consumption of non-production equipment, such as air conditioning, used in factories, to be higher than the power consumption of production equipment. Particularly in summer and winter, the power consumption ratio of air conditioning equipment increases, while the power consumption ratio of production equipment decreases, which can result in exceeding the contracted power amount depending on the operating status of the production equipment. Exceeding the contracted power amount, even temporarily, can lead to higher electricity bills. For this reason, demand control is known, which shuts down production equipment so as not to exceed the contracted power amount (see, for example, Patent Documents 1 and 2). Patent Document 1 describes a technology for controlling power consumption using information on weather changes. Patent Document 2 describes a technology for determining equipment for which power consumption should be controlled, using the ratio between the total time the equipment is operating and the total time it is not operating.

[0003] Controlling equipment power consumption through demand control can lead to production delays and overtime work, potentially reducing production efficiency. Recently, in production sites such as factories, mixed-flow production is practiced, where multiple products are produced on the same production line to accommodate high-mix, low-volume production. In mixed-flow production, different products undergo different processes, such as heat treatment, so the power consumption of the equipment varies depending on the type of product and lot size. Furthermore, when different products are produced on the same production line, setups are required that change molds, jigs, etc. for each product. Therefore, production scheduling that takes setup changes into account for high-mix, low-volume production is required (e.g., Non-Patent Document 1). Non-Patent Document 1 describes a production schedule that combines a genetic algorithm and simulated annealing to simultaneously minimize production completion time and energy consumption. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-228922 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-171192 [Non-patent literature]

[0005] [Non-Patent Document 1] Min Dai et al., "Energy-efficient scheduling for a flexible flow shop using an improved genetic-simulated annealing algorithm", Robotics and Computer-Integrated Manufacturing, Volume 29, Issue 5, October 2013, Pages 418-429 Summary of the Invention [Problem to be solved by the invention]

[0006] The technologies described in Patent Documents 1 and 2 perform demand control so that power does not exceed upper limits, such as contracted power amounts, but do not mention minimizing the manufacturing time of products using production equipment. In particular, there is room for improvement in production scheduling for producing a wide variety of products in small quantities on the same production line. Meanwhile, the production scheduling described in Patent Document 3 determines the order in which equipment is used to execute jobs for products, using equipment whose production capacity and energy consumption are proportional. Therefore, it is not sufficient to plan production schedules for cases in which the energy consumption of equipment or the capacity of each product varies.

[0007] The present invention has been made to solve at least part of the above-mentioned problems, and aims to create a production schedule that improves productivity by performing on-demand control within a range that keeps power usage below the upper limit value. [Means for solving the problem]

[0008] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following forms.

[0009] (1) According to one aspect of the present invention, there is provided a demand control device comprising: an acquisition unit that acquires power demand information related to fluctuations in power demand planned for use by equipment, the power demand information including an upper limit of power available for use by the equipment; product information related to the number of products planned to be produced and delivery dates of the products; and equipment information related to equipment that performs each process of jobs required for product production; an objective function setting unit that sets an objective function that minimizes the completion times of all jobs using the product information and the equipment information; a condition setting unit that sets constraints required for solving the objective function using the power demand information, the product information, and the equipment information; a planning unit that plans a product production schedule by solving the objective function while satisfying the constraints; and a power calculation unit that uses the power demand information to calculate power usage along a time series in the production schedule planned by the planning unit.

[0010] According to this configuration, a product production schedule is planned by solving an objective function set using product information and equipment information so as to satisfy the constraints. Therefore, this configuration allows for the planning of a production schedule that can accommodate the manufacture of a wide variety of products in small quantities or the use of equipment with different production capacities. Furthermore, by using power demand information, the power usage is calculated chronologically in the planned production schedule. The operation status of the equipment in the planned production schedule is controlled so that the calculated power usage falls below the upper limit of the equipment's available power, thereby achieving on-demand control within a range that keeps the power usage below the upper limit. Therefore, according to this configuration, a production schedule that improves productivity is planned after on-demand control is performed.

[0011] (2) In the demand control device of the above aspect, the equipment information may include the power used during the production of each product and the setup time and power usage required for setup changes that occur when processing different jobs in the same process, and the objective function setting unit may set an objective function that includes, as indicators, the power usage during operation of the equipment at any time and the power usage during setup changes. With this configuration, the power consumption required for changeovers that occur when processing different jobs in the same process is set as the objective function. Therefore, a production schedule is created that is optimized by taking into account not only the time required to process the jobs and the power consumption due to equipment operation, but also the power consumption due to changeovers. This further improves the productivity of the planned production schedule, and a production schedule is created in which the power consumption of each production line is leveled.

[0012] (3) In the demand control device of the above aspect, the objective function setting unit may set an objective function that minimizes the sum of the value obtained by multiplying the end times of all jobs by a first weighting coefficient and the value obtained by multiplying the maximum amount of power usage in the production schedule by a second weighting coefficient. According to this configuration, the first weighting coefficient and the second weighting coefficient are set by the production schedule planner, so that a production schedule can be created according to the planner's preferences, with emphasis placed on either job completion times or leveling out power usage.

[0013] (4) The demand control device of the above aspect may further include a first judgment unit that judges whether the production completion time of each product in the production schedule is within the delivery date, and a first adjustment unit, wherein the planning unit plans a production schedule for products produced in lot units, and when the first judgment unit determines that there is a product in the production schedule whose production completion time exceeds the delivery date, the first adjustment unit reduces the number of products included in the lot unit and increases the number of lots, and after the number of lots has increased, the planning unit may plan the production schedule by solving an objective function. With this configuration, if the production completion time in the planned production schedule is not within the delivery date, a new production schedule is planned for the lot unit with the number of products included in the lot unit increased by reducing the number of lots. By increasing the number of lots, the processes on each production line are designed to be more complex. As a result, the processes for products with earlier delivery dates are processed earlier on the production line, and a new production schedule is planned in which the production completion times of the products comply with the delivery dates.

[0014] (5) The demand control device of the above aspect may further include a second determination unit that determines whether the maximum value of power usage in the production schedule planned by the planning unit is equal to or less than the upper limit value, and a second adjustment unit that, when the second determination unit determines that the maximum value exceeds the upper limit value, plans an adjusted production schedule by delaying the start time of a process for a product that is scheduled to be produced at a time when the maximum value exceeds the upper limit value, relative to the production schedule planned by the planning unit. With this configuration, if the power consumption exceeds the upper limit in the planned production schedule, the start time of the product process at the time when the upper limit is exceeded is delayed, thereby reducing the power consumption at that time. As a result, a production schedule is planned based on the planned production schedule in which the maximum power consumption is below the upper limit at all times.

[0015] (6) The demand control device of the above aspect may further include a second determination unit that determines whether the maximum value of power usage in the production schedule planned by the planning unit is equal to or less than the upper limit value, and a third adjustment unit that, when the second determination unit determines that the maximum value exceeds the upper limit value, plans an adjusted production schedule by dividing the production of products scheduled to be produced at the time when the maximum value exceeds the upper limit value. According to this configuration, if the power consumption exceeds the upper limit in the planned production schedule, the processing of the product process at the time when the upper limit is exceeded is divided, thereby reducing the power consumption at that time. By dividing the processing of the product process so that the maximum power consumption is equal to or less than the upper limit, a production schedule is planned based on the planned production schedule in which the maximum power consumption is equal to or less than the upper limit at all times.

[0016] (7) In the demand control device of the above aspect, the power demand information may include the power consumption of non-production equipment that changes over time, and the condition setting unit may set a constraint condition such that the upper limit value at any time is a power value obtained by subtracting the power consumption of the non-production equipment from the contracted power amount. According to this configuration, the power consumption of non-production equipment, which changes in response to factors such as outside air temperature that change over time, is predicted, and the power value available for production equipment is calculated. Constraint conditions are set based on the calculated power value, and demand control is performed so that the total power consumption of non-production equipment and production equipment does not exceed the upper limit.

[0017] (8) In the demand control device of the above aspect, the acquisition unit may further acquire transportation information related to the transportation time required to transport work-in-progress between multiple production lines that perform processes, and the condition setting unit may set constraint conditions using the transportation information in addition to the power demand information, the product information, and the equipment information. This configuration allows constraints to be set that take into account the transport time required for transport between production lines, making it possible to create a production schedule that is more in line with the actual production of products when jobs are carried out on multiple production lines.

[0018] The present invention can be realized in various forms, for example, in the form of a demand control device, a production planning device, a demand control method, a production planning method, a system including these devices or realizing these methods, a computer program for executing these devices or methods, a server device for distributing this computer program, a non-transitory storage medium on which a computer program is stored, etc. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic block diagram of a demand control system according to an embodiment of the present invention. [Figure 2] FIG. 10 is an explanatory diagram of the upper limit of power that can be used by production equipment. [Figure 3] 1 is a block diagram showing a configuration of a production line in the present embodiment. [Figure 4] FIG. 10 is an explanatory diagram of the transport time required to transport a product. [Figure 5] FIG. 10 is an explanatory diagram showing the relationship between the number of products to be produced and the delivery date of each product. [Figure 6] FIG. 2 is an explanatory diagram of the power consumption required when a product is processed on each production line. [Figure 7] FIG. 1 is an explanatory diagram of the cycle time required to process one product. [Figure 8] FIG. 10 is an explanatory diagram of changeover time when products to be processed on the same production line change. [Figure 9] FIG. 10 is an explanatory diagram of decision variables set by an objective function setting unit. [Figure 10] 3 is a flowchart of a demand control method according to the present embodiment. [Figure 11] FIG. 2 is an explanatory diagram of a production schedule according to an embodiment. [Figure 12] FIG. 1 is an explanatory diagram of a production schedule for Comparative Example 1. [Figure 13] FIG. 10 is an explanatory diagram of a production schedule for Comparative Example 2. [Figure 14] FIG. 10 is an explanatory diagram of time-series changes in power consumption in the example and comparative examples 1 and 2. DETAILED DESCRIPTION OF THE INVENTION

[0020] <Embodiment> 1 is a schematic block diagram of a demand control system (demand control device) 100 according to one embodiment of the present invention. The demand control system 100 of this embodiment minimizes or maximizes an objective function that includes the power consumption of each piece of equipment that performs a process for manufacturing a product and the changeover time required to replace that equipment. As a result, the demand control system 100 minimizes the time required to complete all products while suppressing the power consumption at all times during product production to an upper limit value or less.

[0021] As shown in Fig. 1, the demand control system 100 includes a control device 10, a storage device 20 that stores information about products and equipment for producing the products, an input unit 30 that accepts input of various information, an output unit 40 that outputs various information, and a communication unit 50 that transmits and receives information via wireless communication with other devices, servers, etc. In this embodiment, the control device 10 is configured as a personal computer. Details of the control device 10 will be described later. The input unit 30 is configured by a keyboard, a mouse, and a microphone. The output unit 40 is configured by a monitor that displays various images and a speaker.

[0022] The storage device 20 is composed of a hard disk drive (HDD: Hard Disk Drive), etc. The storage device 20 includes an electric power demand database (electric power demand DB) 21 that stores electric power demand information including time-series data on the amount of electric power available at production facilities, a transport information database (transport information DB) 22 that stores transport information including the transport time required for moving between facilities when a product is produced using a plurality of facilities, a product information database (product information DB) 23 that stores product information including the quantity of products to be produced and the delivery date of each product, and an equipment information database (equipment information DB) 24 that stores equipment information including the electric power used by each facility and the changeover time required for replacing equipment.

[0023] FIG. 2 is an explanatory diagram of the upper limit of power that can be used by production equipment. In FIG. 2, the power demand information stored in the power demand DB 21 is a chronological list of non-production equipment power, which is the planned use of non-production equipment, and a production equipment power upper limit (hereinafter simply referred to as "power upper limit"), which is the upper limit of power that can be used by production equipment. The non-production equipment power is the planned power required for operating air conditioning and other equipment in the factory, calculated from weather forecast data such as a weather forecast. The production equipment power upper limit is the power obtained by subtracting the non-production equipment power, which changes over time, from the contracted power amount determined by the contract with the power company. The demand control system 100 creates a production schedule that keeps the power used by the factory's production equipment at all times within the power upper limit. In other words, the power demand information is information regarding the power demand planned to be used by a factory, including production equipment. Note that "production equipment" and "equipment" are synonymous, and the term "equipment" is used to refer to the equipment as "production equipment" in order to use the opposite term "non-production equipment."

[0024] In this embodiment, a factory that produces products has three production lines. Figure 3 is a block diagram showing the configuration of production lines L1 to L3 in this embodiment. In the factory of this embodiment, operations O11 to O13, O21 to O23, and O31 to O33 are processed in processes 1 to 3 on the three production lines L1 to L3, respectively.

[0025] FIG. 4 is an explanatory diagram of the transport time when a product is transported from the exit of a production line to the entrance of a different production line. FIG. 4 shows a table of transport times required for movement between production lines stored in the transport information DB 22. In the production line configuration shown in FIG. 3, for example, a product in the middle of production (work-in-progress) processed in process 1 will next undergo operations O21 to O23 in process 2. This requires transport time to move from the transport exit after operations O11 to O13 in process 1 to the transport entrance where operations O21 to O23 are performed in process 2. FIG. 4 shows a table of transport times determined by the combination of the transport exits of the production lines and the transport exits of the production lines. For example, the transport time shown in FIG. 4 is 3 seconds, which is the time required to move from the transport exit after operation O11 is performed in process 1 of production line L1 to the transport entrance where operation O21 is performed in process 1 of production line L2.

[0026] FIG. 5 is an explanatory diagram showing the relationship between the number of products to be produced and the delivery date of each product in this embodiment. FIG. 5 shows a table listing the relationship between the production quantities and delivery dates of five types of products A to E stored in the product information DB 23. In this embodiment, the delivery dates are set as the numbers of products A to E that must be completed by noon on the first, second, and third days of the three-day period. For example, for product C, 180 units must be produced by noon on the first day, 120 units must be produced by noon on the second day, and 180 units must be produced by noon on the third day. In this embodiment, products A to E all undergo predetermined processing in processes 1 to 3.

[0027] Each of Figures 6 to 8 is an example of equipment information stored in the equipment information DB 24. Figure 6 shows a table of the power consumption required to process each of products A to C when they are processed by equipment arranged on each of production lines L1 to L3. For example, when one product A is processed in process 1 of production lines L1 to L3, the power consumption is 1.25. Similarly, when one product A is processed in process 2 of production lines L1 to L3, the power consumption is 0.3, and when it is processed in process 3 of production lines L1 to L3, the power consumption is 0.25. Note that the power consumption shown in Figure 6 is a normalized value.

[0028] Figure 7 shows a list of the cycle times required to process each of products A to E. For example, the cycle time when one product A is processed in process 1 of production lines L1 to L3 is 60 seconds. Similarly, the cycle time when one product A is processed in process 2 of production lines L1 to L3 is 50 seconds, and the cycle time when one product A is processed in process 3 of production lines L1 to L3 is 60 seconds.

[0029] FIG. 8 shows a table of the changeover times that occur when products A to E being processed in the same process on the same production line are changed. In FIG. 8, products that were processed earlier on a certain production line are represented in rows as "preceding processing," and products that will be processed after the changeover are represented in columns as "subsequent processing." For example, the changeover time that occurs when product A is processed on the production line as the preceding processing and product B is processed as the subsequent processing is 10 seconds. Note that in this embodiment, the changeover time is the same when the preceding processing and subsequent processing are switched. Therefore, the time that occurs when product A is processed as the subsequent processing after product B is processed as the preceding processing is also 10 seconds.

[0030] 1 functions as a CPU (Central Processing Unit) and executes a computer program stored in a ROM (Read Only Memory), not shown, by expanding it into a RAM (Random Access Memory). As a result, the control device 10 not only controls each unit of the control device 10 but also functions as an acquisition unit 11, an objective function setting unit 12, a condition setting unit 13, a scheduling unit (planning unit) 14, a power calculation unit 15, a determination unit (first determination unit, second determination unit) 16, and an adjustment unit (first adjustment unit, second adjustment unit) 17.

[0031] The acquisition unit 11 acquires input information via the input unit 30, power demand information including the production equipment power upper limit (Figure 2) stored in the power demand DB 21, transport time (Figure 4) stored in the transport information DB 22, product information (Figure 5) stored in the product information DB 23, and equipment information (Figures 6 to 8) stored in the equipment information DB 24.

[0032] The objective function setting unit 12 uses the various information acquired by the acquisition unit 11 to set an objective function that completes the production of all products scheduled for production in the shortest time. The objective function setting unit 12 sets an objective function that shortens the completion time of production of all products by maximizing or minimizing the objective function. By maximizing or minimizing the objective function, decision variables are calculated. In this embodiment, processing in each process is performed in lots, with multiple products being one unit. Note that hereinafter, when products are processed in lots, the processing of all processes up to the completion of the products is also referred to as a "job." Furthermore, processing in each process is also referred to as an "operation."

[0033] The objective function setting unit 12 sets indexes in the mathematical model expressed by the following relational expressions (1) to (4) in order to calculate the decision variables.

number

[0034] Fig. 9 is an explanatory diagram of the decision variables set by the objective function setting unit 12. Fig. 9(a) shows the decision variables, i.e., the variables to be optimized, and an explanation of each variable. Fig. 9(b) shows the parameters used when optimizing the decision variables, and an explanation of each parameter.

[0035] In this embodiment, the objective function setting unit 12 calculates the end time C of all jobs expressed by the following formula (5): max Set the objective function to minimize:

number

[0036] 1 sets constraint conditions for the decision variables and parameters using various information acquired by the acquisition unit 11 in order to minimize the set objective function and optimize the decision variables. i In order to select only one of the above, the condition setting unit 13 sets a constraint R1 expressed by the following formula (6).

[0037]

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[0038] The condition setting unit 13 sets the operation O of the process j of the job i. i Start time S ijk and end time C ijk As a constraint R2 relating to the above, the following equations (7) to (9) are set.

[0039]

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[0040] The condition setting unit 13 sets the end time C of the job i. i The following equation (10) is set as constraint R3, where is the end time of the operation of the final process j.

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[0041] The condition setting unit 13 sets the end time C of the production schedule. max is the end time of all jobs i, C i As a constraint R4, the following formula (11) is set.

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[0042] The condition setting unit 13 sets the machine M k When job i' is executed after job i in the setup time SetUp i,i',j,k In order to set the above, a constraint R5 expressed by the following formula (12) is set.

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[0043] The condition setting unit 13 sets the machine M k and machine M for the next process j' k ' Variable Z regarding whether or not there is movement between ikk' As a constraint R6 regarding the above, the following equations (13) to (15) are set.

number

[0044] The condition setting unit 13 uses the transport time stored in the transport information DB 22 to determine the machine M k and machine M for the next process j' k ' Processing time t for movement between ijkand travel time MoveT i,k,k' The following equation (16) is set as the constraint R7 in FIG. 9(b).

number

[0045] The condition setting unit 13 sets a time T d Operation O of process j of job i in i The following formulas (17) to (23) are set as constraints R8 on the execution of the job i. Formulas (17) and (18) are the constraints R8 on the execution of the operation O i The start time of the d Variable A in the case before ijkp (Fig. 9(a)). Equations (19) and (20) are the relations for operation O in process j of job i. i The end time of is an arbitrary time T d Variable B in the case after ijkp (21) to (23) are the relational expressions for (Fig. 9(a)). i is any time T d Whether or not to cross the ijkp This is a relational expression determined using (Figure 9(a)).

[0046]

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[0047] The condition setting unit 13 sets the following equations (24) to (26) as a constraint R9 for determining the job i of the product on standby after the equipment changeover. ijkp is the variable Y at an arbitrary time p as shown in the following equation (24). ijkp and the time (p+1) one step after an arbitrary time p. Note that job i is on standby when the power usage of the equipment reaches the power upper limit and the operation O i The following equations (25) and (26) express the demand state in which the variable Yijkp A variable Z that is 1 when changes from 0 to 1 and 0 otherwise. ijkp defines:

[0048]

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[0049] The condition setting unit 13 sets the following equations (27) to (29) as a constraint R10 on the power consumption of the equipment at an arbitrary time p. p is the sum of the total power consumption of the equipment in operation, which is represented by the term on the left side of the right-hand side, and the total power consumption of the equipment in standby and during changeover, which is represented by the term on the right-hand side. The following equation (28) expresses the power consumption E at any time p. p is equal to or less than the upper limit of the power consumption of the production equipment shown in Figure 2. The following equation (29) expresses the power consumption E p indicates that the power consumption is equal to or less than the maximum value for all equipment.

[0050]

number

[0051] The scheduling unit 14 shown in FIG. 1 creates a production schedule for products A to E by minimizing the objective function (equation (5)) set in the objective function setting unit 12 within a range that satisfies the constraints R1 to R10 set by the condition setting unit 13. The scheduling unit 14 determines the lot unit using various information acquired by the acquisition unit 11. The scheduling unit 14 sets the lot unit such that the number of divided lots is minimized while leveling out the operating time of each process. In a production scheduling problem, the fewer the number of operations to be scheduled, the shorter the calculation time required to create a production schedule. In this embodiment, the lot unit is determined rule-based using the total number of lots as input, but in other embodiments, the lot unit may be determined using mathematical optimization. In this embodiment, the scheduling unit 14 solves the objective function by using mixed integer programming. As a result, the end time C of all jobs i as the objective function expressed by the above equation (5) is obtained while satisfying the constraints R1 to R10. max A production schedule is created that minimizes

[0052] The power calculation unit 15 uses the power demand information to calculate the total power consumption along a time series of the production equipment and non-production equipment in the production schedule drawn up by the scheduling unit 14. The power calculation unit 15 calculates the power consumption at any time along a time series using the drawn up production schedule, the power consumption shown in Fig. 6, and the power consumption of the non-production equipment shown in Fig. 2.

[0053] The determination unit 16 determines whether the production schedule drawn up by the scheduling unit 14 and the time-series power consumption calculated by the power calculation unit 15 satisfy preset constraint conditions. The constraint conditions referred to here are different from the constraints R1 to R10 described above. The constraint conditions in this embodiment are two: a condition of meeting the delivery deadline shown in FIG. 5, and a condition of keeping the power consumption at all times within the power upper limit of the production equipment shown in FIG. 2. If the determination unit 16 determines that the time-series power consumption satisfies the two constraint conditions, it outputs the drawn up production schedule to the output unit 40. For example, the determination unit 16 displays the production schedule as an image such as a Gantt chart on a monitor. If it is determined that the time-series power consumption does not satisfy at least one of the two constraint conditions, the production schedule to be determined is adjusted.

[0054] The adjustment unit 17 prepares a new production schedule by adjusting the production schedule determined by the determination unit 16 to not satisfy two constraints. If the constraints determined by the determination unit 16 to not satisfy at least include the condition of meeting the delivery deadline, the adjustment unit 17 reduces the number of products included in one lot and increases the number of lots. The scheduling unit 14 then prepares a new production schedule that minimizes the objective function again using the increased number of lots. When a production schedule is prepared in units of lots, the next lot cannot be processed on the same equipment until processing of a given lot is completed. In such cases, there is a risk that the delivery deadline of the waiting lot will not be met. In some cases, the delivery deadline can be met by reducing the number of products included in one lot, such as by halving the lot unit, and alternately processing lots of different products.

[0055] On the other hand, if the only constraint determined by the determination unit 16 to be not satisfied is the time-series power usage, the adjustment unit 17 creates an adjusted production schedule in which operations at the time when power usage exceeds the power upper limit are shifted backward. If multiple operations are being performed at the time when power usage exceeds the power upper limit, the adjustment unit 17 prioritizes shifting the operation with the lowest power usage backward. Methods for shifting operations backward include shifting the start time of the operation backward or stopping the operation during the time period when power usage exceeds the power upper limit. The scheduling unit 14 re-creates a production schedule after the lot size increase, and the adjustment of the production schedule by the adjustment unit 17 to shift operations backward is repeated until the determination unit 16 determines that the two constraints are satisfied.

[0056] Fig. 10 is a flowchart of the demand control method of this embodiment. In the demand control flow shown in Fig. 2, first, the acquisition unit 11 performs an acquisition step of acquiring input information via the input unit 30, power demand information (Fig. 2), transportation information (Fig. 4), product information (Fig. 5), and facility information (Figs. 6 to 8) (step S1). The objective function setting unit 12 performs an objective function setting step of setting the objective function shown in the above formula (5) using the various information acquired by the acquisition unit 11 (step S2). The condition setting unit 13 performs a condition setting step of setting constraints R1 to R10 necessary to solve the objective function (step S3). The scheduling unit 14 performs a scheduling step (planning step) of planning a production schedule by solving the objective function (formula (5)) after satisfying the constraints R1 to R10 (step S4). The power calculation unit 15 performs a power calculation step of calculating the power consumption of the production equipment and non-production equipment in accordance with the time series in the planned production schedule (step S5).

[0057] The determination unit 16 determines whether the calculated power consumption satisfies the constraints for meeting the delivery deadline (step S6). If it is determined that the constraints for meeting the delivery deadline are not met, that is, if it is determined that some jobs will not be completed within the delivery deadline (FIG. 5) (step S6: NO), the adjustment unit 17 increases the number of lots in the planned production schedule (step S7). The adjustment unit 17 increases the number of lots by reducing the number of products included in one lot. Thereafter, the scheduling process is performed again for the increased number of lots (step S4).

[0058] If it is determined in the process of step S6 that the deadline compliance constraint is satisfied (step S6: YES), the determination unit 16 determines whether the time-series power consumption constraint is not satisfied, i.e., whether the power consumption at any given time exceeds the power upper limit (production equipment power upper limit) (step S8). If it is determined that the time-series power consumption constraint is satisfied (step S8: YES), the process of step S10, described below, is performed. If it is determined that the time-series power consumption constraint is not satisfied (step S8: NO), the adjustment unit 17 adjusts the planned production schedule (step S9). In this embodiment, the adjustment unit 17 prepares a production schedule by shifting the operation with the lowest power consumption, among multiple operations performed at the time when the total power consumption exceeded the power upper limit, backward so that the total power consumption is within the power upper limit. The planned production schedule is then output to the output unit 40, such as a monitor (step S10), and the demand control flow ends.

[0059] FIG. 11 is an explanatory diagram of a production schedule for an example. FIG. 11 shows a Gantt chart as an example created by the demand control system 100 of this embodiment using the various information shown in FIGS. 2 to 8. FIGS. 12 and 13 are explanatory diagrams of production schedules for Comparative Examples 1 and 2. FIG. 12 shows a Gantt chart for Comparative Example 1 created without demand control. The production schedule for Comparative Example 1 does not have the constraint that total power usage be within the power upper limit, and minimizes the production completion time for all products A to E. The production schedule for Comparative Example 2 shifts back operations that are performed at the time when total power usage exceeds the power upper limit in the production schedule for Comparative Example 1. Therefore, in the Gantt chart for Comparative Example 2 shown in FIG. 13, the production completion times for all products A to E are later than in the Gantt chart for Comparative Example 1 shown in FIG. 12.

[0060] FIG. 14 is an explanatory diagram of the time series changes in power consumption in the Example and Comparative Examples 1 and 2. In FIG. 14, the time series changes in power consumption P01 in the Example are shown by a solid line. The time series changes in power consumption P11 in Comparative Example 1 are shown by a dashed line. The changes in power consumption P12 in Comparative Example 2 are shown by a dashed line. As shown in FIG. 2, the power upper limit of total power consumption is 60, which is shown by a thick solid line in FIG. 14. Of the power consumption in the Example and Comparative Examples 1 and 2, power consumption P11 in Comparative Example 1 exceeds the power upper limit in the range from approximately 8 to 13. On the other hand, power consumption P01 in the Example and power consumption P11 in Comparative Example 2 do not exceed the power upper limit.

[0061] 14, the production completion time of all products A to E in the example is T01. The production completion time of all products A to E in comparative example 1 is T11. The production completion time of all products A to E in comparative example 2 is T12. The production completion time T01 in example 1, in which the power consumption does not exceed the upper limit power, is slightly later than the production completion time T11 in comparative example 1, but is much earlier than the production completion time T12 in comparative example 2.

[0062] As described above, in the demand control system 100 of this embodiment, the objective function setting unit 12 uses various information acquired by the acquisition unit 11 to set the objective function expressed by the above formula (5) that completes the production of all products scheduled for production in the shortest time. The condition setting unit 13 sets constraints R1 to R10 between the decision variables and parameters to minimize the set objective function and optimize the decision variables. The scheduling unit 14 plans a production schedule for products A to E by minimizing the objective function (formula (5)) set in the objective function setting unit 12 within a range that satisfies the constraints R1 to R10 set by the condition setting unit 13. The power calculation unit 15 uses power demand information to calculate the power usage along a time series in the planned production schedule. In this embodiment, the objective function (formula (5)) set using product information and equipment information is solved so as to satisfy the constraints R1 to R10, thereby planning a product production schedule. Therefore, in this embodiment, a production schedule that can be used for manufacturing a wide variety of products in small quantities or using equipment with different production capacities is planned. Furthermore, by using the power demand information, the power usage in a time series in the planned production schedule is calculated. The operation status of the equipment in the planned production schedule is controlled so that the calculated power usage is below the upper limit of available power, thereby realizing on-demand control within a range that keeps the power usage below the upper limit. Therefore, the demand control system 100 of this embodiment performs on-demand control and then plans a production schedule that improves productivity.

[0063] In this embodiment, the determination unit 16 determines whether the production schedule drawn up by the scheduling unit 14 satisfies the constraint of meeting delivery dates. If it is determined that the constraint of meeting delivery dates is not met, the adjustment unit 17 reduces the number of products included in one lot and increases the number of lots. The scheduling unit 14 then uses the increased number of lots to draw up a new production schedule that minimizes the objective function again. In this embodiment, a new production schedule is drawn up for each lot with an increased number of lots. As the number of lots increases, the processes on each production line are designed to be more complex. As a result, processes for products with earlier delivery dates are processed earlier on the production line, and a new production schedule is drawn up in which the production completion times of the products meet the delivery dates.

[0064] The condition setting unit 13 of this embodiment sets the total power consumption E of the non-production equipment and the production equipment at an arbitrary time p as the constraint R10 expressed by the above formulas (27) to (29). p is set to be equal to or less than the production equipment power upper limit shown in FIG. 2. If the determination unit 16 determines that the time-series power consumption constraint condition is not satisfied, the adjustment unit 17 creates an adjusted production schedule by shifting back the operations at the time when the total power consumption of the non-production equipment and the production equipment exceeds the power upper limit. In this embodiment, if the total power consumption in the created production schedule exceeds the upper limit, the start time of the product process at the time when the upper limit is exceeded is delayed, thereby reducing the power consumption at that time. In this way, a production schedule is created based on the created production schedule in which the maximum power consumption is equal to or less than the upper limit at all times.

[0065] In this embodiment, the production equipment power upper limit is the power obtained by subtracting the non-production equipment power, which changes over time, from the contracted power amount determined by the contract with the electric power company. In this embodiment, the power consumption of the non-production equipment, which changes over time, is predicted, and the power value available to the production equipment is calculated. By setting constraints R1 to R10 based on the calculated power value, demand control is performed so that the total power consumption of the non-production equipment and the production equipment does not exceed the production equipment power upper limit.

[0066] The condition setting unit 13 of this embodiment sets constraints R1 to R10 using transport information including transport time required for movement between facilities when a product is produced using multiple facilities. Therefore, in this embodiment, when jobs are performed by multiple production lines, a production schedule that is more in line with actual product production is created.

[0067] <Modifications of the embodiment> The present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the spirit of the present invention, including, for example, the following modifications: In the above-described embodiment, part of the configuration realized by hardware may be replaced by software, and conversely, part of the configuration realized by software may be replaced by hardware.

[0068] <Variation 1> The demand control system 100 of the above embodiment is merely an example, and can be modified within the scope of a production schedule being planned by setting the objective function and constraints R1 to R10 using power demand information, product information, and facility information. For example, the constraints used to solve the objective function do not necessarily include transportation information. The scheduling unit 14 may use a metaheuristic method (such as a genetic algorithm or tabu search) other than integer programming as a method for solving the objective function.

[0069] In the above embodiment, when the determination unit 16 determines that the time-series power consumption does not satisfy the constraint that the power consumption exceeds the power upper limit, the adjustment unit 17 creates a production schedule by shifting the operation at the time when the power consumption exceeds the power upper limit to a later time. However, the constraint may be satisfied by another method. For example, the adjustment unit (third adjustment unit) 17 may create an adjusted production schedule by dividing the number of products to be produced in the operation at the time when the power consumption exceeds the power upper limit. In this modification, dividing the product operation at the time when the power consumption exceeds the power upper limit reduces the power consumption at that time. By dividing the product operation so that the maximum power consumption is below the power upper limit, a production schedule is created based on the planned production schedule in which the maximum power consumption is below the power upper limit at all times. As a division method, for example, the total number of lots, which serves as input, may be increased when determining the lot unit. Alternatively, multiple results may be planned by randomly changing the total number of lots, and the best result may be selected. Alternatively, when randomly changing the total number of lots, optimization may be performed using the total number of lots as a parameter, such as Bayesian optimization.

[0070] <Variation 2> In the above embodiment, the end time C of all jobs as expressed in the above formula (5) max The objective function to minimize the maximum value of the power consumption of all the equipment at all times, D, is set as follows: max The objective function may be set to have the following index: max represents the maximum total power consumption of non-production equipment and production equipment. As shown in equation (30) below, by including the power consumption of all equipment as an index in the objective function, a production schedule can be created that is optimized by taking into account not only the time required to process jobs and the power consumption due to equipment operation, but also the power consumption during changeovers. This further improves the productivity of the planned production schedule, and allows for the creation of a production schedule in which the power consumption of each production line is leveled.

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[0071] The above formula (30) is the end time of all jobs C max and the maximum power consumption D max However, the end time of all jobs C max The first weighting factor multiplied by the maximum power consumption D max The first weighting factor and the second weighting factor may be set to different values. By setting the first weighting factor and the second weighting factor separately, the end time C of all jobs can be calculated. max A production schedule is created according to the planner's preference, with emphasis placed on either the leveling of production capacity or the leveling of power consumption.

[0072] This aspect has been described above based on embodiments and modifications. However, the above-described embodiments are intended to facilitate understanding of this aspect and are not intended to limit this aspect. This aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents thereof are included in this aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate.

[0073] The present invention can also be realized in the following forms. [Application example 1] A demand control device, an acquisition unit that acquires power demand information related to fluctuations in power demand that the equipment is scheduled to use, the power demand information including an upper limit value of power that the equipment can use, product information related to the number of products scheduled to be produced and delivery dates of the products, and equipment information related to the equipment that performs each process of a job required to produce the products; an objective function setting unit that sets an objective function that minimizes the completion times of all jobs using the product information and the equipment information; a condition setting unit that sets constraint conditions necessary to solve an objective function using the power demand information, the product information, and the facility information; a planning unit that plans a production schedule for a product by solving an objective function while satisfying constraint conditions; a power calculation unit that calculates power usage along a time series in the production schedule planned by the planning unit using the power demand information; A demand control device comprising: [Application example 2] The demand control device according to Application Example 1, The facility information includes the power consumed during the production of each product, and the setup time and power consumption required for setup changes that occur when different jobs are processed in the same process, The demand control device, wherein the objective function setting unit sets an objective function including, as indicators, the power consumption during operation of the equipment at any time and the power consumption during changeover. [Application example 3] The demand control device according to Application Example 1 or Application Example 2, The demand control device, wherein the objective function setting unit sets an objective function that minimizes the sum of a value obtained by multiplying the end times of all jobs by a first weighting coefficient and a value obtained by multiplying the maximum amount of power usage in the production schedule by a second weighting coefficient. [Application example 4] The demand control device according to any one of Application Examples 1 to 3, further comprising: a first determination unit that determines whether the production completion time of each product in the production schedule is within the delivery date; A first adjustment unit; Equipped with the planning unit plans a production schedule for products produced in lots, when the first determination unit determines that there is a product whose production completion time in the production schedule exceeds its delivery date, the first adjustment unit reduces the number of products included in each lot unit and increases the number of lots; The demand control device, wherein the planning unit plans a production schedule by solving an objective function after the number of lots has increased. [Application example 5] The demand control device according to any one of Application Examples 1 to 4, further comprising: a second determination unit that determines whether the maximum value of power consumption in the production schedule planned by the planning unit is equal to or less than the upper limit; a second adjustment unit that, when the second determination unit determines that the maximum value will exceed the upper limit, prepares an adjusted production schedule by delaying the start time of a process for a product that is scheduled to be produced at the time when the maximum value will exceed the upper limit, relative to the production schedule prepared by the preparation unit; A demand control device comprising: [Application Example 6] The demand control device according to any one of Application Examples 1 to 5, further comprising: a second determination unit that determines whether the maximum value of power consumption in the production schedule planned by the planning unit is equal to or less than the upper limit; a third adjustment unit that, when the second determination unit determines that the maximum value will exceed the upper limit value, creates an adjusted production schedule by dividing the production of products that are scheduled to be produced at the time when the maximum value exceeds the upper limit value; A demand control device comprising: [Application Example 7] The demand control device according to any one of Application Examples 1 to 6, The power demand information includes power usage by non-production facilities that changes over time, The condition setting unit sets a constraint condition that the upper limit value at any time is a power value obtained by subtracting power used by non-production equipment from a contracted power amount. [Application Example 8] The demand control device according to any one of Application Examples 1 to 7, The acquisition unit further acquires transportation information related to transportation times required to transport work-in-progress between a plurality of production lines that perform processes; The demand control device, wherein the condition setting unit sets constraint conditions using the transportation information in addition to the power demand information, the product information, and the facility information. [Application Example 9] A demand control method, comprising: an acquisition step of acquiring power demand information relating to fluctuations in power demand that the equipment is scheduled to use, the power demand information including an upper limit value of power that the equipment can use, product information relating to the number of products scheduled to be produced and delivery dates of the products, and equipment information relating to the equipment that performs each process of a job required to produce the products; an objective function setting step of setting an objective function that minimizes the completion times of all jobs using the product information and the equipment information; a condition setting step of setting constraint conditions necessary to solve an objective function using the power demand information, the product information, and the facility information; a planning process for planning a production schedule for the product by solving an objective function while satisfying constraints; a power calculation step of calculating power consumption along a time series in a planned production schedule using the power demand information; A demand control method that performs the above. [Application Example 10] A computer program comprising: an acquisition function for acquiring power demand information relating to fluctuations in power demand that the equipment is scheduled to use, the power demand information including an upper limit value of power that the equipment can use, product information relating to the number of products scheduled to be produced and the delivery date of the products, and equipment information relating to the equipment that performs each process of a job required to produce the products; an objective function setting function that sets an objective function that minimizes the completion times of all jobs using the product information and the equipment information; a condition setting function that sets constraint conditions necessary to solve an objective function using the power demand information, the product information, and the facility information; A planning function that creates a production schedule for a product by solving an objective function while satisfying constraints. a power calculation function that calculates the power consumption along a time series in the production schedule planned by the planning function using the power demand information; A computer program that causes a computer to execute the following. [Explanation of symbols]

[0074] 10...Control device 11…Acquisition part 12...Objective function setting section 13...Condition setting section 14...Scheduling Department (Planning Department) 15...Power calculation section 16... Judgment section (first judgment section, second judgment section) 17...Adjustment section (first adjustment section, second adjustment section, third adjustment section) 20…Storage device 30...Input section 40...Output section 50…Communications Department 100...Demand control system (demand control device) C max …End time of all jobs 21…Electricity demand DB 22...Transportation information DB 23…Product information DB 24…Equipment information DB D max …Maximum power consumption of all facilities R1~R10…constraints

Claims

1. A demand control device, an acquisition unit that acquires power demand information related to fluctuations in power demand that the equipment is scheduled to use, the power demand information including an upper limit value of power that the equipment can use, product information related to the number of products scheduled to be produced and delivery dates of the products, and equipment information related to the equipment that performs each process of a job required to produce the products; an objective function setting unit that sets an objective function that minimizes the completion times of all jobs using the product information and the equipment information; a condition setting unit that sets constraint conditions necessary to solve an objective function using the power demand information, the product information, and the facility information; a planning unit that plans a production schedule for a product by solving an objective function while satisfying constraint conditions; a power calculation unit that calculates power usage along a time series in the production schedule planned by the planning unit using the power demand information; A demand control device comprising:

2. The demand control device according to claim 1, The facility information includes the power consumed during the production of each product, and the setup time and power consumption required for setup changes that occur when different jobs are processed in the same process, The demand control device, wherein the objective function setting unit sets an objective function including, as indicators, the power consumption during operation of the equipment at any time and the power consumption during changeover.

3. The demand control device according to claim 2, The objective function setting unit sets an objective function that minimizes the sum of a value obtained by multiplying the end times of all jobs by a first weighting coefficient and a value obtained by multiplying the maximum amount of power usage in the production schedule by a second weighting coefficient.

4. The demand control device according to claim 1, further comprising: a first determination unit that determines whether the production completion time of each product in the production schedule is within the delivery date; A first adjustment unit; Equipped with the planning unit plans a production schedule for products produced in lots, when the first determination unit determines that there is a product whose production completion time in the production schedule exceeds its delivery date, the first adjustment unit reduces the number of products included in each lot unit and increases the number of lots; The demand control device, wherein the planning unit plans a production schedule by solving an objective function after the number of lots has increased.

5. The demand control device according to claim 1, further comprising: a second determination unit that determines whether the maximum value of power consumption in the production schedule planned by the planning unit is equal to or less than the upper limit; a second adjustment unit that, when the second determination unit determines that the maximum value will exceed the upper limit, prepares an adjusted production schedule by delaying the start time of a process for a product that is scheduled to be produced at the time when the maximum value will exceed the upper limit, relative to the production schedule prepared by the preparation unit; A demand control device comprising:

6. The demand control device according to claim 1, further comprising: a second determination unit that determines whether the maximum value of power consumption in the production schedule formulated by the formulation unit is equal to or less than the upper limit; a third adjustment unit that, when the second determination unit determines that the maximum value will exceed the upper limit value, creates an adjusted production schedule by dividing the production of products that are scheduled to be produced at the time when the maximum value exceeds the upper limit value; A demand control device comprising:

7. The demand control device according to claim 1, The power demand information includes power usage by non-production facilities that changes over time, The condition setting unit sets a constraint condition that the upper limit value at any time is a power value obtained by subtracting power used by non-production equipment from a contracted power amount.

8. The demand control device according to any one of claims 1 to 7, The acquisition unit further acquires transportation information related to transportation times required to transport work-in-progress between a plurality of production lines that perform processes; The demand control device, wherein the condition setting unit sets constraint conditions using the transportation information in addition to the power demand information, the product information, and the facility information.

9. A demand control method, comprising: an acquisition step of acquiring power demand information relating to fluctuations in power demand that the equipment is scheduled to use, the power demand information including an upper limit value of power that the equipment can use, product information relating to the number of products scheduled to be produced and delivery dates of the products, and equipment information relating to the equipment that performs each process of a job required to produce the products; an objective function setting step of setting an objective function that minimizes the completion times of all jobs using the product information and the equipment information; a condition setting step of setting constraint conditions necessary to solve an objective function using the power demand information, the product information, and the facility information; a planning process for planning a production schedule for the product by solving an objective function while satisfying constraints; a power calculation step of calculating power consumption along a time series in a planned production schedule using the power demand information; A demand control method that performs the above.

10. A computer program comprising: an acquisition function for acquiring power demand information relating to fluctuations in power demand that the equipment is scheduled to use, the power demand information including an upper limit value of power that the equipment can use, product information relating to the number of products scheduled to be produced and the delivery date of the products, and equipment information relating to the equipment that performs each process of a job required to produce the products; an objective function setting function that sets an objective function that minimizes the completion times of all jobs using the product information and the equipment information; a condition setting function that sets constraint conditions necessary to solve an objective function using the power demand information, the product information, and the facility information; A planning function that creates a production schedule for a product by solving an objective function while satisfying constraints. a power calculation function that calculates the power consumption along a time series in the production schedule planned by the planning function using the power demand information; A computer program that causes a computer to execute the following.

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