Estimation device, estimation system, estimation method, and program

Abstract

This estimation device comprises: an estimation unit that estimates the average service life of a plated steel sheet and the service life variation in a use environment of the plated steel sheet on the basis of the use environment, the component content of the plating layer of the plated steel sheet, and the thickness of the plating layer; and a determination unit that determines the minimum service life of the plated steel sheet in the use environment on the basis of a predetermined coefficient for the variation, and the estimated average and variation. The estimation device may further comprise a communication unit that transmits the determined minimum service life to a user terminal.

Description

Estimation device, estimation system, estimation method, and program

[0001] The present invention relates to an estimation device, estimation system, estimation method, and program. This application claims priority under Japanese Patent Application No. 2025-037626, filed in Japan on March 10, 2025, the contents of which are incorporated herein by reference.

[0002] Plated steel sheets are steel sheets that have been plated on their surface. Compared to unplated steel sheets, plated steel sheets have improved corrosion resistance. Plated steel sheets are widely used in various industries, including automobiles, construction, and home appliances. For example, in the automotive industry, they are sometimes used to improve the durability of vehicles. For example, in the construction industry, they are sometimes used to improve the durability of exterior materials.

[0003] If plated steel sheets lack sufficient corrosion resistance, the lifespan of vehicles and other equipment using those sheets will be shortened, resulting in increased costs. Therefore, plated steel sheets are required to have a long service life.

[0004] Japanese Patent Publication No. 2020-148541 Japanese Patent Publication No. 2006-234802

[0005] The corrosion rate of plated steel sheets varies depending on the operating environment (for example, in an atmospheric environment, temperature, wetting time (humidity), amount of airborne salt (sea salt particles), amount of sulfur oxides, and precipitation), and the composition of the plating layer (parameters). For this reason, it is difficult to uniformly determine the minimum service life of plated steel sheets. Furthermore, new plated steel sheet products are being developed to accommodate the wide range of operating environments, and the minimum service life of plated steel sheets requires greater flexibility and precision than ever before.

[0006] Therefore, from the perspective of product reliability and peace of mind, a system is needed in which the minimum service life of plated steel sheets is accurately determined and presented to the user as the guaranteed service life. Furthermore, such a system is also necessary from the perspective of extending the product's lifespan through timely maintenance. However, there is a problem in that it is not possible to determine the minimum service life of plated steel sheets based on conditions specified by the user.

[0007] In view of the above circumstances, the present invention aims to provide an estimation device, estimation system, estimation method, and program that can determine the minimum service life of a plated steel sheet based on conditions specified by the user.

[0008] (1) One aspect of the present invention is an estimation device comprising: an estimation unit that estimates the average service life and the variation of the service life of a plated steel sheet in a given usage environment, based on the usage environment of the plated steel sheet, the component content of the plating layer of the plated steel sheet, and the thickness of the plating layer; and a determination unit that determines the minimum service life of the plated steel sheet in a given usage environment based on a predetermined coefficient for the variation and the estimated average and variation.

[0009] (2) One aspect of the present invention is the estimation device described in (1) above, further comprising a communication unit that transmits the determined minimum service life to a user terminal.

[0010] (3) In one aspect of the present invention, in the estimation device described in (2) above, the communication unit obtains information on the usage environment, the component content of the plating layer, and the thickness of the plating layer from the user terminal.

[0011] (4) In one aspect of the present invention, in the estimation device described in (2) above, the communication unit obtains information on the usage environment and the desired service life of the plated steel sheet from the user terminal, the estimation unit estimates the average and the variation in the usage environment for a predetermined range of the component content of the plating layer and a predetermined range of the thickness of the plating layer, the determination unit determines a combination of the component content of the plating layer and the thickness of the plating layer such that the minimum service life is equal to or greater than the desired service life of the plated steel sheet by searching within the predetermined range of the component content of the plating layer and the predetermined range of the thickness of the plating layer, and the communication unit transmits the determined combination and the minimum service life corresponding to the determined combination to the user terminal.

[0012] (5) In one aspect of the present invention, in the estimation device described in (4) above, the communication unit further obtains a predetermined range of the component content of the plating layer and a predetermined range of the thickness of the plating layer from the user terminal.

[0013] (6) In one aspect of the present invention, in the estimation device described in (4) or (5) above, the determination unit determines by the search the combination that brings the minimum service life closest to the desired service life, or the combination that brings the minimum service life the longest.

[0014] (7) In one aspect of the present invention, in the estimation device described in (1) or (2) above, the estimation unit estimates the average and variation in the usage environment for a predetermined range of the component content of the plating layer and a predetermined range of the thickness of the plating layer, and the determination unit determines a combination of the component content of the plating layer and the thickness of the plating layer such that the minimum service life is equal to or greater than the desired service life of the plated steel sheet, by searching within the predetermined range of the component content of the plating layer and the predetermined range of the thickness of the plating layer.

[0015] (8) In one aspect of the present invention, in the estimation device described in any one of (1) to (7) above, the estimation unit further estimates the average and the variation based on the component content of the steel sheet in the plated steel sheet and the thickness of the steel sheet.

[0016] (9) One aspect of the present invention is an estimation system comprising an estimation device and a user terminal, wherein the estimation device includes an estimation unit that estimates the average service life and the variation of the service life of the plated steel sheet in the usage environment based on the usage environment of the plated steel sheet, the component content of the plating layer of the plated steel sheet, and the thickness of the plating layer; a determination unit that determines the minimum service life of the plated steel sheet in the usage environment based on a predetermined coefficient for the variation and the estimated average and variation; and a first communication unit that transmits the determined minimum service life to the user terminal, and the user terminal includes a second communication unit that obtains the determined minimum service life from the estimation device and a presentation unit that presents the obtained minimum service life to the user.

[0017] (10) In one aspect of the present invention, in the estimation system described in (9) above, the second communication unit further transmits the usage environment information, the component content of the plating layer, and the thickness of the plating layer to the estimation device, and the first communication unit further obtains the usage environment information, the component content of the plating layer, and the thickness of the plating layer from the user terminal.

[0018] (11) In one aspect of the present invention, in the estimation system described in (9) above, the second communication unit transmits information about the usage environment and the desired service life of the plated steel sheet to the estimation device, the first communication unit obtains information about the usage environment and the desired service life of the plated steel sheet from the user terminal, the estimation unit estimates the average and the variation in the usage environment for a predetermined range of the component content of the plating layer and a predetermined range of the thickness of the plating layer, and the determination unit determines the component content of the plating layer and the minimum service life such that the minimum service life is equal to or greater than the desired service life of the plated steel sheet. The combination of the plating layer thickness is determined by searching within a predetermined range of the component content of the plating layer and a predetermined range of the plating layer thickness. The first communication unit further transmits the determined combination and the minimum service life corresponding to the determined combination to the user terminal. The second communication unit further obtains the determined combination and the minimum service life corresponding to the determined combination from the estimation device. The presentation unit presents the determined combination and the minimum service life corresponding to the determined combination to the user.

[0019] (12) In one aspect of the present invention, in the estimation system described in (11) above, the second communication unit further transmits a predetermined range of the component content of the plating layer and a predetermined range of the thickness of the plating layer to the estimation device, and the first communication unit further obtains a predetermined range of the component content of the plating layer and a predetermined range of the thickness of the plating layer from the user terminal.

[0020] (13) In one aspect of the present invention, in the estimation system described in (11) or (12) above, the determination unit determines by the search the combination that brings the minimum useful life closest to the desired useful life, or the combination that brings the minimum useful life the longest.

[0021] (14) In one aspect of the present invention, in the estimation system described in any one of (9) to (13) above, the estimation unit further estimates the average and the variation based on the component content of the steel sheet of the plated steel sheet and the thickness of the steel sheet.

[0022] (15) One aspect of the present invention is an estimation method performed by an estimation device, comprising: an estimation step of estimating the average service life and the variation of the service life of the plated steel sheet in the usage environment, based on the usage environment of the plated steel sheet, the component content of the plating layer of the plated steel sheet, and the thickness of the plating layer; and a determination step of determining the minimum service life of the plated steel sheet in the usage environment based on a predetermined coefficient for the variation and the estimated average and variation.

[0023] (16) One aspect of the present invention is a program for causing a computer to perform the following steps: estimate the average service life and the variation of the service life of the plated steel sheet in the usage environment, based on the usage environment of the plated steel sheet, the component content of the plating layer of the plated steel sheet, and the thickness of the plating layer; and determine the minimum service life of the plated steel sheet in the usage environment, based on a predetermined coefficient for the variation and the estimated average and variation.

[0024] This invention makes it possible to determine the minimum service life of plated steel sheets based on conditions specified by the user.

[0025] This figure shows an example of the configuration of the estimation system in the first embodiment. This figure shows an example of training data in the first embodiment. This figure shows an example of user-specified conditions in the first embodiment. This figure shows an example of the average estimated service life and the variation in estimated service life in the first embodiment. This is a sequence diagram showing an example of the operation of the estimation system in the first embodiment. This is a sequence diagram showing an example of the operation of the estimation system in a modified version of the first embodiment. This figure shows an example of the configuration of the estimation system in the second embodiment. This figure shows an example of user-specified conditions in the second embodiment. This figure shows an example of recommended conditions and warranty years presented to the user in the second embodiment. This is a sequence diagram showing an example of the operation of the estimation system in the second embodiment. This figure shows an example of user-specified conditions in the first modified version of the second embodiment. This figure shows an example of recommended conditions and warranty years presented to the user in the first modified version of the second embodiment. This figure shows an example of recommended conditions and warranty years not presented to the user in the second modified version of the second embodiment. This is a sequence diagram showing an example of the operation of the estimation system in the third modified version of the second embodiment. This is a sequence diagram showing an example of the operation of the estimation system in the fourth modified version of the second embodiment. This figure shows an example of the configuration of the estimation system in the third embodiment. This figure shows an example of the configuration of the estimation system in the fourth embodiment.

[0026] Embodiments of the present invention will be described in detail with reference to the drawings. (First Embodiment) Figure 1 is a diagram showing an example of the configuration of the estimation system 1a in the first embodiment. There is variation in the actual service life of plated steel sheets. For this reason, even if the service life estimated using, for example, simple regression is presented to the user as the guaranteed service life, the actual service life for that user may not meet the guaranteed service life. Therefore, in the first embodiment, the estimation system 1a determines the minimum service life of the plated steel sheet based on conditions specified by the user (specified conditions) so that the actual service life is equal to or greater than the guaranteed service life.

[0027] The minimum service life is the minimum number of years until the plated steel sheet reaches a specified condition. For example, the specified condition may be a state in which at least one hole appears in the plated steel sheet. In other words, the minimum service life may be the lifespan before the hole appears. For example, the specified condition may be a state in which 20% of the steel material of the plated steel sheet is corroded. In other words, the minimum service life may be the lifespan before 20% of the steel material is corroded. For example, the specified condition may be a state in which 1% of the surface area of ​​the plated steel sheet is covered with red rust. In other words, the minimum service life may be the lifespan before the plating is completed. The specified condition may be defined by the company that presents the warranty period to the user, by the user, or by agreement between the user and the company. The minimum service life may also be determined based on the variability (e.g., variance or standard deviation) of a normal distribution with the service life of the plated steel sheet as the mean.

[0028] The estimation system 1a comprises an estimation device 2, a user terminal 3, and a communication line 4. The estimation device 2 is used, for example, by a person belonging to a company that presents the warranty period to a user. The user terminal 3 is used by a user who receives the warranty period presentation. The estimation device 2 comprises a storage device 21, a learning unit 22, a first communication unit 23, an estimation unit 24, and a determination unit 25. The user terminal 3 comprises a second communication unit 31, an operation unit 32, a presentation unit 33, a memory 34, and a control unit 35.

[0029] Each of the estimation device 2 and the user terminal 3 is implemented as software by a processor such as a CPU (Central Processing Unit) executing a program stored in at least one of a storage device and memory having a non-volatile recording medium (non-temporary recording medium). The program may be recorded on a computer-readable recording medium, or it may be recorded in at least one of the storage device and memory via a communication line 4. Computer-readable recording media include, for example, portable media such as flexible disks, magneto-optical disks, ROMs (Read Only Memory), CD-ROMs (Compact Disc Read Only Memory), and non-temporary recording media such as hard disks or solid-state drives (SSDs) built into computer systems.

[0030] Each of the estimation device 2 and the user terminal 3 may be implemented using hardware that includes electronic circuits (or circuits) such as LSI (Large Scale Integrated Circuit), ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), or FPGA (Field Programmable Gate Array).

[0031] The minimum service life of a plated steel sheet largely depends on the component content of the plating layer and the thickness of the plating layer. Furthermore, although less dependent than the above, various chemical conversion coatings applied to the plating layer (e.g., chromate coatings or chromate-free coatings) also affect the minimum service life of the plated steel sheet. The harsher the operating environment of the plated steel sheet, the shorter the minimum service life; therefore, the minimum service life of a plated steel sheet largely depends on the operating environment. Accordingly, the estimation device 2 determines the minimum service life based, for example, on the operating environment of the plating layer, the component content of the plating layer, and the thickness of the plating layer.

[0032] The estimation device 2 may further determine the minimum service life of the plated steel sheet based on the component content of the steel sheet and the thickness of the steel sheet. That is, the estimation device 2 may determine the minimum service life based, for example, on the usage environment of the plating layer, the component content of the plating layer, the thickness of the plating layer, the component content of various chemical conversion coatings on the plating layer, the component content of the steel sheet, and the thickness of the steel sheet. Here, a corrosion category can be used as the usage environment.

[0033] Figure 2 shows an example of training data in the first embodiment. The storage device 21 stores training data for machine learning. In the training data, the component content of the plating layer, the thickness of the plating layer ("plating thickness"), the component content of the steel sheet, the thickness of the steel sheet ("steel sheet thickness"), the corrosion category, and the service life measured in an exposure test or accelerated corrosion test are associated.

[0034] The corrosion category of a plated steel sheet with a chemical conversion coating applied to the plating layer, and the service life measured in an exposure test or accelerated corrosion test of the plated steel sheet, may be used as training data. In this training data, in addition to the component content of the plating layer, the plating thickness of the plating layer, the component content of the steel sheet, the steel sheet thickness, and the corrosion category, other indicators and the measured service life may be associated. Other indicators include, for example, the type of chemical conversion coating formed on the plating layer and the thickness of that chemical conversion coating. However, there is no practical problem even if these other indicators are not included in the training data, because the majority of the influence on service life is due to the component content of the plating layer, the plating thickness, the component content of the steel sheet, and the steel sheet thickness.

[0035] There is a predetermined correlation between the results of this accelerated corrosion test and the results of this exposure test. Here, the unit of service life in the exposure test is "years (days, months)", while the unit of service life in the accelerated corrosion test is "cycles". For this reason, in the training data, the units are standardized through unit conversion. For example, when the unit is converted from cycles (#cycle) to years, the service life (#year) is expressed as shown in equation (1) using a constant α for each corrosion category.

[0036] #year=α・#cycle…(1)

[0037] Here, the constant α is determined within the company based on, for example, the results of an exposure test and the results of an accelerated corrosion test.

[0038] The components of the plating layer are not necessarily limited to specific plating components. In FIG. 2, the components of the plating layer are Zn, Al, and Mg as an example. The components of the steel sheet are also not necessarily limited to specific steel sheet components. In FIG. 2, the components of the steel sheet are Fe, Cr, and Ni as an example. The number of combinations of Zn, Al, Mg, Fe, Cr, and Ni is 15 sets as an example. The unit for each component is %. The total of each component of Zn, Al, and Mg is 100%. Similarly, the total of each component of Fe, Cr, and Ni is 100%. The corrosion category is, for example, a corrosion category defined in ISO 12944, ISO 9223 to 9226, and DIN 50929-3 (for example, corrosion categories "C1" to "C5" for atmospheric environments, or corrosion category "Im3" for buried in soil). The corrosion category may be determined based on standards. That is, the corrosion category may be determined from corrosion weight loss obtained by an exposure test of a standard test piece, or from data of corrosive environmental factors (for example, in the case of an atmospheric environment, average temperature, wetting time (humidity), airborne salt content (sea salt particles), sulfur oxide content, and precipitation amount). Further, the corrosion category may be determined by being converted from the aforementioned accelerated corrosion test data. The types of service life are, as an example, 9 types (38 years, 41 years, 45 years, 62 years, ...). Since data having 15 sets of combinations and 9 types of service life are combined, the total number of learning data is 135 (=15×9).

[0039] Note that, as in "No. 1" illustrated in FIG. 2, by including data that does not contain "Ni" in the learning data, the arbitrary nature of alloy components is improved in input to a trained machine learning model that uses the learning data. Further, as in "No. 2" and "No. 4" illustrated in FIG. 2, by including data that is the same except for the service life in the learning data, the output (service life) from a trained model having a neural network such as a Bayesian neural network has variation.

[0040] The learning unit 22 uses a machine learning technique to input, into a learning model, information about the service environment of the plated steel sheet, the component content of the plating layer, the thickness of the plating layer, the component content of the steel sheet of the plated steel sheet, and the thickness of the steel sheet of the plated steel sheet that are contained in the learning data. The learning unit 22 uses a machine learning technique to acquire the average service life and the variation in service life (for example, standard deviation) from the learning model. In this way, the learning unit 22 generates a trained model from the learning model.

[0041] The machine learning technique is not limited to a specific learning technique, and is, for example, a Gaussian process regression learning technique or a Bayesian inference learning technique. The trained model includes a neural network that outputs the average service life and the standard deviation of the service life. The trained model includes, for example, a Bayesian neural network.

[0042] It should be noted that when the results of exposure tests and the results of accelerated corrosion tests are expanded, the learning data may be updated periodically. By assigning a version to the trained model, the version of the trained model may be managed. In addition, a user may specify, to the estimation unit 24, the version of the trained model to be used for estimation.

[0043] Figure 3 is a diagram showing an example of conditions specified by a user in the first embodiment. The first communication unit 23 acquires, from the second communication unit 31, information about the service environment of the plated steel sheet, the component content of the plating layer, the thickness of the plating layer, the component content of the steel sheet of the plated steel sheet, and the thickness of the steel sheet of the plated steel sheet.

[0044] Figure 4 shows an example of the estimated average service life and the estimated variation in service life in the first embodiment. The estimation unit 24 estimates the average service life and the variation in service life of the plated steel sheet in the usage environment of the plated steel sheet, based on the usage environment of the plated steel sheet, the component content of the plating layer of the plated steel sheet, the thickness of the plating layer, the component content of the steel sheet of the plated steel sheet, and the thickness of the steel sheet. Here, the estimation unit 24 inputs the usage environment of the plated steel sheet, the component content of the plating layer of the plated steel sheet, the thickness of the plating layer, the component content of the steel sheet of the plated steel sheet, and the thickness of the steel sheet into a trained model. The estimation unit 24 obtains the average μ and variation σ of service life from the trained model as estimation results.

[0045] Alternatively, instead of using a trained model with a neural network to estimate the mean μ and variability σ based on the specified conditions, the estimation unit 24 may use a lookup table in which the specified conditions are associated with the mean μ and variability σ to estimate the mean μ and variability σ based on the specified conditions.

[0046] The determination unit 25 determines the minimum service life t of the plated steel sheet in the usage environment of the plated steel sheet, based on a predetermined coefficient β for variation, the estimated average μ of service life and variation σ. ｍｉｎ This is determined as shown in equation (2).

[0047] t ｍｉｎ = μ - β・σ …(2)

[0048] Here, β is a coefficient representing the allowable variability relative to the mean μ. β may be determined by the company presenting the warranty period to the user, by the user, or by agreement between the user and the company. For example, if β = 3, a variability of approximately 99.73% is allowed. In the specified conditions illustrated in Figure 3, for example, if β is 3, the minimum useful life t ｍｉｎ This is 58.49 years. In this case, for example, 58 years, which is 58.49 years with the decimal part truncated, will be presented to the user as the warranty period.

[0049] The second communication unit 31 transmits information about the usage environment of the plated steel sheet, the component content of the plating layer, the thickness of the plating layer, the component content of the steel sheet in the plated steel sheet, and the thickness of the steel sheet in the plated steel sheet. The information about the usage environment of the plated steel sheet is, for example, a corrosion category defined in ISO 12944, ISO 9223-9226, and DIN 50929-3. The second communication unit 31 obtains the minimum service life determined by the determination unit 25 from the first communication unit 23.

[0050] The operation unit 32 is an operating device such as a mouse, keyboard, or touch panel. The operation unit 32 accepts input operations from the user for conditions specified by the user. For example, the operation unit 32 accepts input operations for conditions such as information on the usage environment of the plated steel sheet, the component content of the plating layer, the thickness of the plating layer, the component content of the steel sheet in the plated steel sheet, and the thickness of the steel sheet in the plated steel sheet.

[0051] The display unit 33 is, for example, a display unit having a display device. The display unit 33 may also be, for example, an audio output unit having a speaker. The display unit 33 has a minimum useful life t obtained from the estimation device 2. ｍｉｎ This will be presented to the user as the warranty period for the plated steel sheet.

[0052] Memory 34 stores programs executed by the control unit 35. Memory 34 may also store data acquired from the estimation device 2 by the second communication unit 31. The control unit 35 controls the operation of each functional unit of the user terminal 3.

[0053] Next, an example of the operation of the estimation system 1a will be described. Figure 5 is a sequence diagram showing an example of the operation of the estimation system 1a in the first embodiment. The second communication unit 31 transmits information about the usage environment of the plated steel sheet, the component content of the plating layer, the thickness of the plating layer, the component content of the steel sheet in the plated steel sheet, and the thickness of the steel sheet (step S101).

[0054] The first communication unit 23 acquires information on the usage environment of the plated steel sheet, the component content of the plating layer, the thickness of the plating layer, the component content of the steel sheet in the plated steel sheet, and the thickness of the steel sheet (step S102). The estimation unit 24 estimates the average service life and the variation in service life of the plated steel sheet in the usage environment based on the usage environment of the plated steel sheet, the component content of the plating layer, the thickness of the plating layer, the component content of the steel sheet in the plated steel sheet, and the thickness of the steel sheet (step S103). The determination unit 25 determines the minimum service life t of the plated steel sheet in the usage environment based on a predetermined coefficient β for the variation and the estimated average service life μ and variation σ. ｍｉｎ Determine (step S104).

[0055] The first communications unit 23 has a determined minimum useful life t ｍｉｎ The minimum service life of the plated steel sheet is transmitted to the user terminal 3 as the warranty period (step S105). The second communication unit 31 acquires the determined minimum service life (step S106). The presentation unit 33 presents the acquired minimum service life to the user as the warranty period of the plated steel sheet (step S107).

[0056] As described above, the first communication unit 23 acquires information on the usage environment of the plated steel sheet, the component content of the plating layer, the thickness of the plating layer, the component content of the steel sheet in the plated steel sheet, and the thickness of the steel sheet. The estimation unit 24 estimates the average service life of the plated steel sheet and the variation in service life (e.g., standard deviation) in the usage environment of the plated steel sheet based on the usage environment of the plated steel sheet, the component content of the plating layer, the thickness of the plating layer, the component content of the steel sheet in the plated steel sheet, and the thickness of the steel sheet. The determination unit 25 determines the minimum service life t of the plated steel sheet in the usage environment based on a predetermined coefficient β for the variation, the estimated average μ, and the variation σ. ｍｉｎ The warranty period is determined as (=μ - β・σ).

[0057] This makes it possible to determine the minimum service life of the plated steel sheet based on conditions specified by the user. Furthermore, it is possible to present the minimum service life of the plated steel sheet to the user as the warranty period for the plated steel sheet.

[0058] (Modification of the first embodiment) The estimation unit 24 may estimate the average service life of the plated steel sheet and the variation in service life without using conditions related to the steel sheet of the plated steel sheet (component content and thickness of the steel sheet).

[0059] The learning unit 22 uses machine learning techniques to input information about the usage environment of the plated steel sheet, the component content of the plating layer, and the thickness of the plating layer from the training data into the learning model. The learning unit 22 uses machine learning techniques to obtain the average service life and the variability of service life (e.g., standard deviation) from the learning model. In this way, the learning unit 22 generates a trained model from the learning model.

[0060] Figure 6 is a sequence diagram showing an example of the operation of the estimation system 1a in a modified version of the first embodiment. The second communication unit 31 transmits information about the usage environment of the plated steel sheet, the component content of the plating layer, and the thickness of the plating layer (step S201). The first communication unit 23 acquires information about the usage environment of the plated steel sheet, the component content of the plating layer, and the thickness of the plating layer (step S202). The estimation unit 24 estimates the average service life and the variation in service life of the plated steel sheet in the usage environment of the plated steel sheet based on the usage environment of the plated steel sheet, the component content of the plating layer of the plated steel sheet, and the thickness of the plating layer (step S203). Each step from step S204 to step S207 is the same as each step from step S104 to step S107 illustrated in Figure 5.

[0061] (Second Embodiment) In the second embodiment, the main difference from the first embodiment is that the combination of parameters such that the minimum useful life (warranty period) is equal to or greater than the desired useful life is determined by search. The second embodiment will be explained focusing on the differences from the first embodiment.

[0062] Figure 7 shows an example configuration of the estimation system 1b in the second embodiment. The estimation system 1b comprises an estimation device 2, a user terminal 3, and a communication line 4. The estimation device 2 comprises a storage device 21, a learning unit 22, a first communication unit 23, an estimation unit 24, and a determination unit 25. The user terminal 3 comprises a second communication unit 31, an operation unit 32, a presentation unit 33, a memory 34, and a control unit 35.

[0063] The user is looking for plated steel sheets whose minimum service life (guarantee period) under specific conditions (acceptable range) is equal to or greater than the desired service life. In other words, in order to ensure user convenience, a mechanism is needed to present the user with the conditions (e.g., the content of the plating layer) of plated steel sheets that satisfy the conditions (acceptable range) specified by the user. Therefore, in the second embodiment, the estimation device 2 presents the user with the conditions (e.g., a combination of the content of the plating layer and the thickness of the plating layer) of plated steel sheets that satisfy the conditions specified by the user.

[0064] The estimation unit 24 estimates the average and variability of the service life of the plated steel sheet under the usage environment of the plated layer, based on a predetermined range for the component content of the plating layer, a predetermined range for the thickness of the plating layer, a predetermined range for the component content of the steel sheet, and a predetermined range for the thickness of the steel sheet.

[0065] The determination unit 25 determines a combination (recommended conditions) of the component content of the plating layer, the thickness of the plating layer, the component content of the steel sheet, and the thickness of the steel sheet, such that the minimum service life is equal to or greater than the desired service life of the plated steel sheet, by searching within a predetermined range for the component content of the plating layer, a predetermined range for the thickness of the plating layer, a predetermined range for the component content of the steel sheet, and a predetermined range for the thickness of the steel sheet.

[0066] Here, the decision unit 25 performs a search using a mathematical optimization algorithm. The mathematical optimization algorithm is not limited to a specific algorithm, but examples include Newton's method, a genetic algorithm, or Particle Swarm Optimization (PSO). The estimation unit 24 and the decision unit 25 perform the search processes exemplified below, for example, from (A1) to (A7).

[0067] (A1) The estimation unit 24 randomly selects conditions (parameters) from a predetermined range of conditions specified by the user. (A2) The estimation unit 24 estimates the average service life and the variation in service life of the plated steel sheet in the usage environment of the plated steel sheet for the selected conditions. (A3) The determination unit 25 determines the minimum service life t based on the average service life μ and the variation in service life σ. ｍｉｎ (=μ - β・σ) is determined. (A4) The estimation unit 24 or the determination unit 25 calculates the error between the desired service life specified by the user and the determined minimum service life. (A5) The estimation unit 24 selects a modified condition (parameter) from a predetermined range of conditions specified by the user that reduces the error. (A6) The estimation unit 24 and the determination unit 25 repeatedly perform steps (A1) to (A5) until the error falls below the first threshold. (A7) The determination unit 25 may determine the combination that minimizes the error (absolute error) between the minimum service life and the desired service life as a recommended condition by searching within each range. That is, the determination unit 25 may determine the combination (recommended condition) that brings the minimum service life closest to the desired service life by searching within each range.

[0068] In addition, in (A6) above, the estimation unit 24 and the determination unit 25 may repeatedly perform steps (A1) to (A5) until the error exceeds the second threshold. Here, the determination unit 25 may determine the combination that has the longest minimum service life (recommended condition) among the combinations in which the minimum service life is equal to or greater than the desired service life of the plated steel sheet, by searching within each range.

[0069] Figure 8 shows an example of user-specified conditions in the second embodiment. In Figure 8, the desired service life (the number of years of warranty desired by the user) is, for example, 50 years. The first communication unit 23 acquires information on the usage environment of the plated steel sheet, the desired service life of the plated steel sheet, a predetermined range for the component content of the plating layer, a predetermined range for the thickness of the plating layer, a predetermined range for the component content of the steel sheet in the plated steel sheet, and a predetermined range for the thickness of the steel sheet. The user-specified conditions (specified conditions) include predetermined ranges (tolerance ranges) for each parameter. Each tolerance range is predetermined by the user.

[0070] Figure 9 shows an example of recommended conditions and warranty period presented to the user in the second embodiment. The determination unit 25 optimizes the minimum service life by, for example, performing particle group optimization on an objective function that represents the absolute error between the minimum service life (warranty period) and the desired service life of "50 years". In Figure 9, the determined minimum service life (warranty period) is 50.1 years as an example. The presentation unit 33 presents the combination (recommended conditions) obtained by the second communication unit 31 to the user. Here, the presentation unit 33 presents the obtained minimum service life of "50.1" to the user as the warranty period for the plated steel sheet.

[0071] Next, an example of the operation of the estimation system 1b will be described. Figure 10 is a sequence diagram showing an example of the operation of the estimation system 1b in the second embodiment. The second communication unit 31 transmits information on the usage environment of the plated steel sheet, the desired service life of the plated steel sheet, a predetermined range (tolerance range) of the component content of the plating layer, a predetermined range of the thickness of the plating layer, a predetermined range of the component content of the steel sheet in the plated steel sheet, and a predetermined range of the thickness of the steel sheet (step S401).

[0072] The first communication unit 23 acquires information on the usage environment of the plated steel sheet, the desired service life of the plated steel sheet, a predetermined range for the component content of the plating layer, a predetermined range for the thickness of the plating layer, a predetermined range for the component content of the steel sheet in the plated steel sheet, and a predetermined range for the thickness of the steel sheet (step S402).

[0073] The estimation unit 24 estimates the average and variation of the service life of the plated steel sheet in the service environment of the plating layer with respect to a predetermined range of the component content of the plating layer, a predetermined range of the thickness of the plating layer, a predetermined range of the component content of the steel sheet of the plated steel sheet, and a predetermined range of the thickness of the steel sheet (step S403).

[0074] The determination unit 25 determines a combination (recommended condition) of the component content of the plating layer, the thickness of the plating layer, the component content of the steel sheet of the plated steel sheet, and the thickness of the steel sheet that satisfies that the minimum service life is not less than the desired service life of the plated steel sheet by searching within the predetermined range of the component content of the plating layer, the predetermined range of the thickness of the plating layer, the predetermined range of the component content of the steel sheet of the plated steel sheet, and the predetermined range of the thickness of the steel sheet. The determination unit 25 may determine the combination (recommended condition) where the minimum service life is closest to the desired service life by searching within each range. The determination unit 25 may also determine the combination (recommended condition) where the minimum service life is the longest by searching within each range (step S404).

[0075] The first communication unit 23 transmits the determined combination (recommended condition) and the minimum service life t corresponding to the determined combination ｍｉｎ (warranty period) to the user terminal 3 (step S405). The second communication unit 31 acquires the determined minimum service life and the minimum service life t corresponding to the determined combination ｍｉｎ (warranty period) (step S406). The presentation unit 33 presents the acquired combination (recommended condition) to the user. In addition, the presentation unit 33 presents the acquired minimum service life to the user as the warranty period of the plated steel sheet (step S407).

[0076] As described above, the first communication unit 23 obtains information on the usage environment, the desired service life of the plated steel sheet, a predetermined range for the component content of the plating layer, a predetermined range for the thickness of the plating layer, a predetermined range for the component content of the steel sheet in the plated steel sheet, and a predetermined range for the thickness of the steel sheet from the user terminal 3. The estimation unit 24 estimates the average μ and variation σ of the service life of the plated steel sheet in the usage environment of the plating layer, based on the predetermined range for the component content of the plating layer, the predetermined range for the thickness of the plating layer, the predetermined range for the component content of the steel sheet in the plated steel sheet, and the predetermined range for the thickness of the steel sheet. The determination unit 25 determines a combination (recommended conditions) of the component content of the plating layer, the thickness of the plating layer, the component content of the steel sheet, and the thickness of the steel sheet, such that the minimum service life is equal to or greater than the desired service life of the plated steel sheet, by searching within a predetermined range for the component content of the plating layer, a predetermined range for the thickness of the plating layer, a predetermined range for the component content of the steel sheet, and a predetermined range for the thickness of the steel sheet.

[0077] This makes it possible to determine the minimum service life of the plated steel sheet based on conditions specified by the user. Furthermore, it is possible to present the minimum service life of the plated steel sheet to the user as the warranty period for the plated steel sheet.

[0078] (First Modification of the Second Embodiment) Figure 11 shows an example of user-specified conditions in the first modification of the second embodiment. In the specified conditions illustrated in Figure 11, the component content of the steel plate and the thickness of the steel plate are specified as fixed values ​​rather than within an allowable range. The component content of the plating layer and the thickness of the plating layer may also be specified as fixed values ​​rather than within an allowable range.

[0079] Figure 12 shows an example of recommended conditions and warranty period presented to the user in the first modified example of the second embodiment. In Figure 12, the minimum service life (warranty period) is 50.1 years, as an example. The presentation unit 33 presents the acquired combination (recommended conditions) to the user. The presentation unit 33 also presents the acquired minimum service life of "50.1" to the user as the warranty period for the plated steel sheet.

[0080] (Second Modification of the Second Embodiment) Figure 13 shows an example of recommended conditions and warranty period that are not presented to the user in a second modification of the second embodiment. If there is a discrepancy between the minimum useful life (e.g., 68.0 years) and the desired useful life (e.g., 100 years), the determination unit 25 may notify the presentation unit 33 using the first communication unit 23 that recommended conditions cannot be presented. Instead of presenting recommended conditions to the user, the presentation unit 33 notifies the user that recommended conditions cannot be presented.

[0081] (Third modified example of the second embodiment) The estimation unit 24 may estimate the average service life of the plated steel sheet and the variation in service life without using conditions related to the steel sheet of the plated steel sheet (component content and thickness of the steel sheet).

[0082] Figure 14 is a sequence diagram showing an example of the operation of the estimation system 1b in a third modified example of the second embodiment. The second communication unit 31 transmits information on the usage environment of the plated steel sheet, the desired service life of the plated steel sheet, a predetermined range (tolerance range) of the component content of the plating layer, and a predetermined range of the thickness of the plating layer (step S501). The first communication unit 23 acquires information on the usage environment of the plated steel sheet, the desired service life of the plated steel sheet, a predetermined range of the component content of the plating layer, and a predetermined range of the thickness of the plating layer (step S502). The estimation unit 24 estimates the average and variability of the service life of the plated steel sheet in the usage environment of the plating layer, based on the predetermined range of the component content of the plating layer and the predetermined range of the thickness of the plating layer (step S503). Each step from step S504 to step 508 is the same as each step from step S404 to step S408 illustrated in Figure 10.

[0083] (Fourth Modification of the Second Embodiment) The predetermined range (search range) does not need to be specified by the user. For example, if the user specifies the thickness of the plating layer as 30 μm, the predetermined range may be set to a range of 30 ± 20 μm based on a predetermined width of 20 μm centered on the specified 30 μm. The same applies to the ranges of parameters other than the thickness of the plating layer (component content of the plating layer, component content of the steel sheet in the plated steel sheet, and thickness of the steel sheet).

[0084] Figure 15 is a sequence diagram showing an example of the operation of the estimation system 1b in a fourth modified example of the second embodiment. The second communication unit 31 transmits information about the usage environment of the plated steel sheet and the desired service life of the plated steel sheet (step S601). The first communication unit 23 acquires information about the usage environment of the plated steel sheet and the desired service life of the plated steel sheet (step S602). Each step from step S503 to step 508 is the same as each step from step S403 to step S408 illustrated in Figure 10.

[0085] (Third Embodiment) In the third embodiment, the main difference from the first and second embodiments is that the estimation device 2 is provided on the user terminal 3. The third embodiment will be explained focusing on the differences from the first and second embodiments.

[0086] Figure 16 shows an example configuration of the estimation system 1c in the third embodiment. The estimation system 1c comprises a user terminal 3, a communication line 4, and a learning device 5. The learning device 5 is used, for example, by a person in charge belonging to a certain company. The user terminal 3 is used by a user. The user terminal 3 comprises an estimation device 2, a second communication unit 31, an operation unit 32, a presentation unit 33, a memory 34, and a control unit 35. The estimation device 2 comprises an estimation unit 24 and a determination unit 25. The learning device 5 comprises a storage device 21 (database device), a learning unit 22, and a first communication unit 23.

[0087] The first communication unit 23 transmits the trained model stored in the memory device 21 to the second communication unit 31. The second communication unit 31 retrieves the trained model from the first communication unit 23. The second communication unit 31 records the retrieved trained model in the memory 34. The memory 34 stores the trained model retrieved from the estimation device 2 by the second communication unit 31.

[0088] In the user terminal 3, the control unit 35 controls the operation of each functional unit provided in the user terminal 3. The estimation device 2 obtains the conditions specified by the user from the operation unit 32. Based on the conditions specified by the user, the estimation unit 24 estimates the average service life and the variation in service life of the plated steel sheet in the usage environment of the plated steel sheet. Based on a predetermined coefficient β for the variation, the estimated average μ, and the variation σ, the determination unit 25 determines the minimum service life t of the plated steel sheet in the usage environment of the plated steel sheet. ｍｉｎ The presentation unit 33 determines the following. The presentation unit 33 presents the user with a combination of parameters (recommended conditions). The presentation unit 33 presents the user with the minimum service life as the guaranteed period for the plated steel sheet.

[0089] As described above, the estimation device 2 may be provided in the user terminal 3. In the user terminal 3, the estimation unit 24 may estimate the average service life and the variation in service life of the plated steel sheet in the usage environment of the plated steel sheet, based on conditions specified by the user. The determination unit 25 determines the minimum service life t of the plated steel sheet in the usage environment of the plated steel sheet based on a predetermined coefficient β for the variation, the estimated average μ and variation σ. ｍｉｎ You may decide that.

[0090] This makes it possible to determine the minimum service life of the plated steel sheet based on conditions specified by the user. Furthermore, it is possible to present the minimum service life of the plated steel sheet to the user as the warranty period for the plated steel sheet.

[0091] (Fourth Embodiment) In the fourth embodiment, the main difference from the third embodiment is that the storage device 21 (database device) is provided in the user terminal 3. The fourth embodiment will be explained focusing on the differences from the third embodiment.

[0092] Figure 17 shows an example configuration of the estimation system 1d in the fourth embodiment. The estimation system 1d comprises a user terminal 3 and a communication line 4. The user terminal 3 comprises an estimation device 2, a second communication unit 31, an operation unit 32, a presentation unit 33, a memory 34, and a control unit 35. A server (not shown) that distributes programs may be connected to the communication line 4.

[0093] The second communication unit 31 obtains a program via the communication line 4. This program includes a trained model. The second communication unit 31 records the program in at least one of the storage device 21 and the memory 34.

[0094] The learning unit 22 generates a trained model by executing a program stored in at least one of the storage device 21 and the memory 34. The estimation unit 24 estimates the average service life and the variation in service life of the plated steel sheet in the usage environment of the plated steel sheet by executing a program stored in at least one of the storage device 21 and the memory 34. The determination unit 25 determines the minimum service life t of the plated steel sheet in the usage environment of the plated steel sheet based on a predetermined coefficient β for variation, the estimated average service life μ and variation σ, by executing a program stored in at least one of the storage device 21 and the memory 34. ｍｉｎ The determination unit 25 may perform a search for recommended conditions by executing a program stored in at least one of the storage device 21 and memory 34.

[0095] As described above, the storage device 21 (database device) may be provided in the user terminal 3. The user terminal 3 may estimate the average service life and the variation in service life of the plated steel sheet in the usage environment of the plated steel sheet. The user terminal 3 estimates the minimum service life t of the plated steel sheet in the usage environment of the plated steel sheet. ｍｉｎ The user terminal 3 may decide on the following. The user terminal 3 may perform a search for recommended conditions.

[0096] This makes it possible to determine the minimum service life of the plated steel sheet based on conditions specified by the user. Furthermore, it is possible to present the minimum service life of the plated steel sheet to the user as the warranty period for the plated steel sheet.

[0097] Although embodiments of this invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and includes designs and the like that do not depart from the spirit of this invention. Furthermore, each embodiment may be combined.

[0098] 1a, 1b, 1c, 1d... Estimation system, 2... Estimation device, 3... User terminal, 4... Communication line, 5... Learning device, 21... Storage device, 22... Learning unit, 23... First communication unit, 24... Estimation unit, 25... Decision unit, 31... Second communication unit, 32... Operation unit, 33... Presentation unit, 34... Memory, 35... Control unit

Claims

1. An estimation device comprising: an estimation unit that estimates the average service life and the variation of the service life of a plated steel sheet in a given usage environment, based on the usage environment of the plated steel sheet, the component content of the plating layer of the plated steel sheet, and the thickness of the plating layer; and a determination unit that determines the minimum service life of the plated steel sheet in the given usage environment based on a predetermined coefficient for the variation and the estimated average and variation.

2. The estimation device according to claim 1, further comprising a communication unit for transmitting the determined minimum service life to a user terminal.

3. The estimation device according to claim 2, wherein the communication unit obtains information about the usage environment, the component content of the plating layer, and the thickness of the plating layer from the user terminal.

4. The estimation device according to claim 2, wherein the communication unit obtains information on the usage environment and the desired service life of the plated steel sheet from the user terminal; the estimation unit estimates the average and variation in the usage environment for a predetermined range of the component content of the plating layer and a predetermined range of the thickness of the plating layer; the determination unit determines a combination of the component content of the plating layer and the thickness of the plating layer such that the minimum service life is equal to or greater than the desired service life of the plated steel sheet, by searching within the predetermined range of the component content of the plating layer and the predetermined range of the thickness of the plating layer; and the communication unit transmits the determined combination and the minimum service life corresponding to the determined combination to the user terminal.

5. The estimation device according to claim 4, wherein the communication unit further obtains a predetermined range of the component content of the plating layer and a predetermined range of the thickness of the plating layer from the user terminal.

6. The estimation device according to claim 4 or 5, wherein the determination unit determines by the search the combination that brings the minimum useful life closest to the desired useful life, or the combination that brings the minimum useful life the longest.

7. The estimation device according to claim 1 or 2, wherein the estimation unit estimates the average and variation in the usage environment for a predetermined range of the component content of the plating layer and a predetermined range of the thickness of the plating layer, and the determination unit determines a combination of the component content of the plating layer and the thickness of the plating layer such that the minimum service life is equal to or greater than the desired service life of the plated steel sheet, by searching within the predetermined range of the component content of the plating layer and the predetermined range of the thickness of the plating layer.

8. The estimation device according to claim 1 or 2, wherein the estimation unit further estimates the average and the variation based on the component content of the steel sheet and the thickness of the steel sheet.

9. Estimation system comprising an estimation device and a user terminal, wherein the estimation device includes: an estimation unit that estimates the average service life and the variation of the service life of the plated steel sheet in the usage environment based on the usage environment of the plated steel sheet, the component content of the plating layer of the plated steel sheet, and the thickness of the plating layer; a determination unit that determines the minimum service life of the plated steel sheet in the usage environment based on a predetermined coefficient for the variation and the estimated average and variation; and a first communication unit that transmits the determined minimum service life to the user terminal, and the user terminal includes: a second communication unit that obtains the determined minimum service life from the estimation device; and a presentation unit that presents the obtained minimum service life to the user.

10. The estimation system according to claim 9, wherein the second communication unit further transmits information about the usage environment, the component content of the plating layer, and the thickness of the plating layer to the estimation device, and the first communication unit further obtains information about the usage environment, the component content of the plating layer, and the thickness of the plating layer from the user terminal.

11. The second communication unit transmits the information on the usage environment and the desired service life of the plated steel sheet to the estimation device; the first communication unit obtains the information on the usage environment and the desired service life of the plated steel sheet from the user terminal; the estimation unit estimates the average and variation in the usage environment for a predetermined range of the component content of the plating layer and a predetermined range of the thickness of the plating layer; the determination unit determines a combination of the component content of the plating layer and the thickness of the plating layer such that the minimum service life is equal to or greater than the desired service life of the plated steel sheet, by searching within the predetermined range of the component content of the plating layer and the predetermined range of the thickness of the plating layer; the first communication unit further transmits the determined combination and the minimum service life corresponding to the determined combination to the user terminal. The estimation system according to claim 9, wherein the second communication unit further obtains the determined combination and the minimum service life corresponding to the determined combination from the estimation device, and the presentation unit presents the determined combination and the minimum service life corresponding to the determined combination to the user.

12. The estimation system according to claim 11, wherein the second communication unit further transmits a predetermined range of the component content of the plating layer and a predetermined range of the thickness of the plating layer to the estimation device, and the first communication unit further obtains a predetermined range of the component content of the plating layer and a predetermined range of the thickness of the plating layer from the user terminal.

13. The estimation system according to claim 11 or 12, wherein the determination unit determines by the search the combination that brings the minimum useful life closest to the desired useful life, or the combination that brings the minimum useful life the longest.

14. The estimation system according to claim 9, wherein the estimation unit further estimates the average and the variation based on the component content of the plated steel sheet and the thickness of the steel sheet.

15. Estimation method performed by an estimation device, comprising: an estimation step of estimating the average service life and the variation of the service life of the plated steel sheet in the usage environment, based on the usage environment of the plated steel sheet, the component content of the plating layer of the plated steel sheet, and the thickness of the plating layer; and a determination step of determining the minimum service life of the plated steel sheet in the usage environment based on a predetermined coefficient for the variation and the estimated average and variation.

16. A program for causing a computer to perform the following steps: a procedure for estimating the average service life and the variation in service life of a plated steel sheet in a given usage environment, based on the usage environment of the plated steel sheet, the component content of the plating layer of the plated steel sheet, and the thickness of the plating layer; and a procedure for determining the minimum service life of the plated steel sheet in a given usage environment, based on a predetermined coefficient for the variation and the estimated average and variation.

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