CN114936685A - Repairable part multi-level inventory optimization method and device - Google Patents

Abstract

The application is suitable for the technical field of inventory optimization, and provides a repairable piece multistage inventory optimization method and a repairable piece multistage inventory optimization device, wherein the repairable piece multistage inventory optimization method comprises the following steps: determining an average annual demand of the repairable base level for the outfield repairable LRU based on the equipment and repairable associated data; determining the fault isolation rate of the repairable part; determining the annual average demand of spare parts of each stage of the repairable part based on the annual average demand of the repairable part base level on the LRU of the outfield repairable part and the fault isolation rate of the repairable part; determining the spare parts number of each stage of supply channel based on the annual average demand of each stage of spare parts of the repairable part; and establishing a spare part inventory optimization model based on the spare part number optimization target of each level of supply channel. The method and the device can complete a set of spare part equipment spare part multistage inventory optimization configuration scheme, meet the use requirement of the spare part and reduce the cost to the minimum.

Description

Repairable part multi-level inventory optimization method and device

Technical Field

The application belongs to the technical field of inventory optimization, and particularly relates to a repairable multi-level inventory optimization method and device.

Background

At present, in the prior art, sufficient and accurate spare part inventory is needed for equipment for storing spare parts so as to deal with the loss caused by various uncertain factors. However, due to the lack of spare parts and the urgent need for maintenance to reduce down time, cost control is often ignored, all of which are caused by poor spare part inventory management. Therefore, under the requirement of the total cost limit of the system, it is necessary to complete a set of spare part equipment spare part multi-level inventory optimization configuration scheme, which not only meets the use requirement of the spare part, but also reduces the cost to the minimum.

Disclosure of Invention

In order to solve the problems in the related art, embodiments of the present application provide a repairable part multi-level inventory optimization method and apparatus, which can complete a set of spare part equipment spare part multi-level inventory optimization configuration scheme, thereby not only meeting the use requirements of spare parts, but also reducing the cost to the minimum.

The application is realized by the following technical scheme:

in a first aspect, an embodiment of the present application provides a repairable piece multi-level inventory optimization method, including: determining an average annual demand of the repairable base level for the outfield repairable LRU based on the associated data of equipment and repairable pieces; determining a fault isolation rate of the repairable piece; determining the annual average demand of spare parts of each stage of the repairable part based on the annual average demand of the repairable part base level on the outer field repairable part LRU and the fault isolation rate of the repairable part; determining the spare parts number of each stage of supply channel based on the annual average demand of each stage of spare parts of the repairable part; and establishing a spare part inventory optimization model based on the spare part number optimization target of each level of supply channel.

In one possible implementation manner of the first aspect, the repairable part includes an external revisable part LRU and an internal revisable part SRU; the outfield repairable LRU is a component detached from the equipment, and the outfield repairable SRU is a component of the outfield repairable.

In one possible implementation manner of the first aspect, the determining an average annual demand of the repair base level to the outfield repair LRU comprises:

by passing

Calculating the annual average demand of the repairable element base level to the outfield repairable element LRU; wherein i is the number of the repairable piece, the item number i of the LRU of the outer field repairable piece is 0, and the rest i represents the item number of the SRU of the inner field repairable piece; j represents a base level number, k represents a relay level number, and k is 0 corresponding to the base level; DC (direct current) _i Representing the ratio of the operation time of the repairable part i to the total operation time of the equipment system; RIP _i Representing the in-situ repair probability of the repairable part i; HW represents equipment average run time; z _i Representing the number of repairable parts i installed on the upper-level part; n is a radical of _j The number of equipment sites used; MTBF (methyl tert-butyl ether) _i Representing the mean time to failure of the repairable element i; ROK _i And representing the false detection probability of the repairable part i, wherein the false detection probability is the probability that the part i is the cause of equipment failure.

In a possible implementation manner of the first aspect, the determining a fault isolation rate of the repairable element includes:

by passing

Calculating the fault isolation rate q of the repairable part; the fault isolation rate indicates the ratio of the number of faults detected in the equipment component g to be not more than a specified ambiguity and the number of faults detected in the same time, wherein g is the number of the component in the next layer above the repairable part i, MTBF, and the detected fault isolation rate is correctly isolated in a specified time by a specified method _g Indicating mean time to failure, RIP, of the component g _g Representing the in-situ repair probability of the part g; ROK _g Indicating the false detection probability of the component g.

In a possible implementation manner of the first aspect, the determining an average annual demand of the spare parts of each stage of the repairable part includes: determining an average annual demand for SRUs by the repairable element base level; determining an annual average demand of the repairable relay stage for SRUs and LRUs; determining an average annual demand of the repairable ground level for SRUs and LRUs; the determining an average annual demand on SRUs by the repairable element base level comprises:

by passing

m _ij ＝m _0j ·r _0j ·q _ij

Calculating the average annual demand of the base level for SRUs;

the determining an average annual demand on SRUs and LRUs by the repairable relay stage comprises:

by passing

Calculating the annual average demand of the repairable relay level on the LRU;

by passing

Calculating the average annual demand of the repairable relay stage on the SRU;

the determining the average annual demand of the repairable ground level on the SRUs and the LRUs comprises:

by passing

Calculating the annual average demand of the repairable element base level to the LRU;

by passing

Calculating the average annual demand of the repairable element-based ground level on the SRU; wherein r is _0j Probability of defective parts for LRU being repairable at base level, r _ij Probability that a failed component that is an SRU can be repaired at the base level; r is _0k Probability that the fault piece of the LRU can be repaired at the relay stage k; r is _ik Probability that a failed component that is an SRU can be repaired at relay level k.

In a possible implementation manner of the first aspect, the determining the number of supply channel reserves at each stage includes: determining the supply channel spare part number expectation and variance of the base-level LRU; the supply channel spare part number of the base-level LRU comprises the following steps: when there is no SRU delay, the number of LRU in the base repair channel and the number of LRU in the base repair channel delayed because the base stock has no needed SRU;

determining supply channel spare part number expectation and variance of the relay stage SRU and the LRU; the number of supply channel spares for the relay stage SRU includes: the number of SRUs under repair and sent for repair, and the number of delays caused by no SRU backup at the base level; the number of supply channel components of the trunk-stage LRU includes: the number of LRU when there is no shortage, the number of delays due to no SRU backup in the relay stage, and the number of LRU repair delays due to base LRU shortage;

determining supply channel spare part number expectations and variances for the base tier SRUs and LRUs; the supply channel spare part count of the base level SRU includes: the number of the SRUs under repair and sent for repair and the number of delays caused by the fact that the relay level has no SRU backup; the supply channel spare part count of the base level SRU includes: the number of LRUs in no shortage, the number of delays due to no SRU backup at the base level, and the number of LRU repair delays due to LRU shortage at the trunk level;

the determining of the spare part number expectation and variance of the base level supply channel LRU comprises:

by passing

ρ ₀₀ ＝m ₀₀ ·q _i0 /m _i0

Calculating the proportion of the SRU requirement generated by the LRU repair to the total SRU requirement at the base level;

by passing

Calculating the supply channel spare part number expectation of the base-level LRU;

by passing

Calculating the variance of the supply channel spare part number of the base-level LRU;

the determining supply channel spare part number expectations and variances for the trunk SRUs and LRUs includes:

by passing

f _ik ＝m _ik (1-r _ik )/m _i0

Calculating the proportion of the SRU requirement generated by the shortage of the relay-level SRU to the total number of the base-level SRU requirement;

by passing

E[X _ik ]＝m _ik ·[(1-r _ik )t _ik +r _ik T _ik ]+f _ik ·EBO(s _i0 |m _i0 T _i0 )

Calculating the supply channel spare part number expectation of the relay stage SRU; by passing

Var[X _ik ]＝m _ik ·[(1-r _ik )t _ik +r _ik T _ik ]+f _ik ·(1-f _ik )·EB0(s _i0 |m _i0 ·T _i0 )+f ² _ik ·VBO(s _i0 |m _i0 ·T _i0 )；

Calculating the supply channel spare part number variance of the relay stage SRU;

by passing

ρ _0k ＝m _0k ·q _ik ·r _0k /m _ik

Calculating the proportion of the SRU requirement in the total SRU requirement generated by LRU repair;

by passing

f _0k ＝m _0k (1-r _0k )/m ₀₀

Calculating the proportion of the LRU demand generated by the shortage of the relay LRU to the total number of the ground-level LRU demand;

by passing

Calculating the supply channel spare part number expectation of the relay LRU;

by passing

Calculating the supply channel spare part number variance of the relay-level LRU;

the determining supply channel spare part number expectations and variances for the base tier SRUs and LRUs comprises:

by passing

f _ij ＝m _ij (1-r _ij )/m _ik

Calculating the proportion of SRU requirements generated by the shortage of the base-level SRUs to the total number of the SRUs of the relay level;

by passing

E[X _ij ]＝m _ij ·[(1-r _ij )t _ij +r _ij T _ij ]+f _ij ·EBO(s _ik |m _ik T _ik )

Calculating the supply channel spare part number expectation of the base-level SRU;

by passing

Var[X _ij ]＝m _ij ·[(1-r _ij )t _ij +r _ij T _ij ]+f _ij ·(1-f _ij )·EBO(s _ik |m _ik ·T _ik )+f ² _ij ·VBO(s _ik |m _ik T _ik )

Calculating the variance of the number of supply channel spare parts of the base-level SRU;

by passing

f _0j ＝m _0j (1-r _0j )/m _0k

Calculating the proportion of the LRU requirement generated by the shortage of the base-level LRU to the total number of the relay-level LRU requirement;

by passing

Calculating a supply channel spare part number expectation of the base-level LRU;

by passing

Calculating a supply channel spare part number variance of the base-level LRU; wherein EBO () is the expected shortage number of each stage of spare parts, VBO () is the variance of shortage number of each stage of spare parts, T ₀₀ Mean repair time for LRU for base level, T _i0 Average repair time to SRU for base grade; t is _0k Average repair time to LRU for relay level; t is a unit of _ik Average repair time for the SRU for the relay stage; t is _0j Average repair time to LRU for base level; t is _ij Average repair time to SRU for base level; t is t _ik Average delay time from applying for the relay stage to the base stage to delivering the SRU; t is t _0k The average delay time from applying to the base level for the relay level to delivering the LRU; t is t _ij For base level to relay levelAverage delay time to apply for delivery of SRUs; t is t _0j The base level applies for the relay level for the average latency to delivery of the LRUs.

In a possible implementation manner of the first aspect, the optimization objective includes: seeking equipment availability; said maximum seeking equipment availability is equivalent to a minimum seeking the sum of said base-level LRU shortages; availability of said equipment formed by LRU and SRU of said base level

Calculating; n is a radical of _j Number of equipment at base level, Z ₀ Is the number of LRUs in one equipment, i.e. the number of single machine installations;

assuming that said equipment is comprised of N said LRUs, any failure of said LRUs results in a failure of said equipment, and therefore the equipment availability comprised of N said LRUs is:

for all the guaranteed sites, the system availability is:

in a possible implementation manner of the first aspect, the establishing a spare part inventory optimization model includes: in ensuring the availability of the system target A _m On the premise of minimizing the spare part cost of the system, the established spare part inventory optimization model is as follows:

A _x ≥A _m

wherein C is _i Is the unit price of the spare part i; s _ij Is as followsAnd the inventory of the ith spare part of the j security stations.

In a possible implementation manner of the first aspect, the step of the marginal optimization algorithm used for establishing the spare part inventory optimization model is as follows:

the first step is as follows: initializing the number of system spare parts, order S _ij ＝0；

The second step is that: performing algorithm iteration, and calculating the marginal benefit epsilon of each spare part in each step of iteration process _ij The calculation formula is as follows:

the third step: determining epsilon _ij Adding 1 to the spare parts corresponding to the maximum value;

the fourth step: according to the stock quantity S of the spare parts _ij In combination with the system availability A _x If A is _x Achieving the target availability A of the system _m Then the algorithm iteration is finished to obtain S _ij The matrix is an optimal inventory scheme of spare parts; otherwise, the second step is entered.

In a second aspect, an embodiment of the present application provides a repairable piece multi-level inventory optimization device, including:

the first determining module is used for determining the average demand of each level of spare parts of the repairable part based on the relevant data of the equipment and the repairable part;

the second determination module is used for determining the fault isolation rate of the repairable part;

the third determining module is used for determining annual average demand of each level of spare parts of the repairable part based on the average demand of each level of spare parts and the fault isolation rate;

the fourth determining module is used for determining the number of spare parts of each level of supply channels based on the annual average demand of each level of spare parts of the repairable parts; the number of the spare parts of each level of supply channel comprises: the number of spare parts under repair and delivery for repair and the number of spare parts being replenished;

and the optimization module is used for optimizing the target and establishing a spare part inventory optimization model based on the spare part number of each level of supply channel.

In a third aspect, an embodiment of the present application provides a terminal device, including a memory and a processor, where the memory stores a computer program operable on the processor, and the processor, when executing the computer program, implements the repairable piece multi-level inventory optimization method according to any one of the first aspect.

In a fourth aspect, the present application provides a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, the computer program implements the repairable item multi-level inventory optimization method according to any one of the first aspect.

In a fifth aspect, an embodiment of the present application provides a computer program product, which, when run on a terminal device, causes the terminal device to execute the method described in any one of the above first aspects.

Compared with the prior art, the embodiment of the application has the advantages that:

according to the embodiment of the application, sufficient and accurate spare part inventory is needed for the inventory equipment for equipment spare parts so as to deal with loss caused by various uncertain factors, the expected shortage number of the spare parts is reversely recurred based on the predicted spare part demand by predicting the spare part demand, then the model is constructed, the maintenance model of the maintainable spare parts is optimized, and the multi-level inventory optimization problem is solved by combining a marginal optimization algorithm. Therefore, a set of spare part equipment spare part multistage inventory optimization configuration scheme is completed, the use requirement of the spare part is met, and the cost is reduced to the minimum.

It is understood that the beneficial effects of the second aspect to the fifth aspect can be referred to the related description of the first aspect, and are not described herein again.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the specification.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is a schematic flowchart of a repairable item multi-level inventory optimization method according to an embodiment of the present application;

FIG. 2 is a diagram of a multi-level serviceable spare parts inventory assurance operational mode provided in an embodiment of the present application;

FIG. 3 is a block diagram of an equipment system provided in an embodiment of the present application;

FIG. 4 is a schematic diagram of a multi-level inventory assurance structure provided in an embodiment of the present application;

FIG. 5 is a schematic illustration of a process for servicing a serviceable spare part according to an embodiment of the present application;

FIG. 6 is a schematic diagram illustrating a sequence of calculating a spare part requirement according to an embodiment of the present application;

FIG. 7 is a schematic diagram illustrating a sequence of calculating the number of spare parts supply channels according to an embodiment of the present application;

FIG. 8 is a schematic flowchart of a marginal optimization algorithm provided in an embodiment of the present application;

FIG. 9 is a block diagram of a repairable item multi-level inventory optimization device according to an embodiment of the present application;

fig. 10 is a schematic structural diagram of a terminal device according to an embodiment of the present application.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It should also be understood that the term "and/or" as used in this specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items and includes such combinations.

Reference throughout this specification to "one embodiment" or "some embodiments," or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," or the like, in various places throughout this specification are not necessarily all referring to the same embodiment, but rather "one or more but not all embodiments" unless specifically stated otherwise. The terms "comprising," "including," "having," and variations thereof mean "including, but not limited to," unless otherwise specifically stated.

At present, the stock equipment for equipment spare parts needs to have sufficient and accurate stock of spare parts so as to deal with the loss caused by various uncertain factors. However, due to the lack of spare parts and the urgent need for down time reduction by maintainers, cost control is often ignored, all of which are caused by poor spare part inventory management.

Based on the problems, the embodiment of the application provides a repairable part multi-level inventory optimization method, which determines the annual average demand of a repairable part base level to an LRU (remote location repairable part) of an external field based on relevant data of equipment and repairable parts; determining the fault isolation rate of the repairable part; determining the annual average demand of spare parts of each stage of the repairable part based on the annual average demand of the repairable part base level on the LRU of the outfield repairable part and the fault isolation rate of the repairable part; determining the spare parts number of each stage of supply channel based on the annual average demand of each stage of spare parts of the repairable part; and establishing a spare part inventory optimization model based on the spare part number optimization target of each level of supply channel, thereby completing a set of spare part equipment spare part multistage inventory optimization configuration scheme, meeting the use requirement of spare parts and reducing the cost to the minimum.

In order to make the technical solutions of the present invention better understood by those skilled in the art, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings and the detailed description, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Fig. 1 is a schematic flow chart of a repairable part multi-level inventory optimization method according to an embodiment of the present application, and referring to fig. 1, the repairable part multi-level inventory optimization method is described in detail as follows:

in step 101, based on the relevant data of the equipment and the repairable part, the average annual demand of the repairable part base level on the LRU of the outfield repairable part is determined.

In one possible implementation manner, in step 101, the repairable elements include Line Repair Unit (LRU) and Shop Repair Unit (SRU); the outfield repairable LRU is a component detached from the equipment, and the outfield repairable is a component of the outfield repairable.

By way of example, the simplest expression for repairable multi-level inventory management is: when a piece of equipment is diagnosed as malfunctioning together, the malfunctioning piece is removed from the equipment and sent to the base repair facility. If the base layer supply station has stock spare parts, sending the stock spare parts out and loading the stock spare parts to equipment; otherwise, the user determines that there is a spare part shortage. Since the spare part is directly mounted on the equipment, called first level spare part or field replacement part, the occurrence of a shortage of first level spare parts in the base layer means a stoppage of the equipment.

The failed first-level spare part is sent to the primary service plant and is determined to be repairable or not. If repairable, a base layer repair is scheduled and sent to the base layer supply station after the repair. If the supply station has shortage, the supply station utilizes the repair product to directly fill the shortage; if there is no shortage, the product is put on the shelf of the existing stock for storage. If the base level cannot be repaired, the failed component is sent to a post repair shop, and an application for supplying the spare component is sent to a post warehouse, and after the spare component supply is delayed for a period of time, the base supply station receives a repair product, which is shown in the multi-level maintainable spare component inventory guarantee operation mode diagram of fig. 2.

Illustratively, the LRU out-of-stock causes equipment downtime, and the SRU out-of-stock causes LRU repairs to be delayed. The number of SRUs per LRU depends on the equipment implementation, see the equipment system architecture diagram of fig. 3.

For example, the commonly used security levels in multi-level security include a base level, a relay level and a base level three-level security site structure: the base level site is the lowest level in the multi-level guarantee structure, base level maintenance work is usually carried out on the working site of equipment, an equipment system is also configured on the site, and the site is the weakest in maintenance capacity; the relay station is an upper station of a base level, one relay station can provide spare parts for a plurality of base level stations, and the relay station can complete more complex maintenance of fault parts; the base station belongs to the highest level guarantee unit, not only provides resources for subordinate relay stations, but also can complete any complex fault maintenance. See fig. 4 for a multi-level inventory assurance structure.

Illustratively, assume that a multi-level, multi-tier process begins with a failure of an LRU of a house replacement and sends it to the base tier repository, which replaces it if there is one LRU backup, otherwise there is a shortage at the base tier. The LRU fault parts only account for a small proportion of the repair at the base level, and if the LRU fault parts can be repaired at the base level, the LRU fault parts are transferred to the base level for inventory after being repaired; if the LRU can not be repaired, the LRU is sent to the relay stage for repair, and the LRU is applied for one piece to the relay stage.

If the outfield replacement LRU is repaired at the base level, it is assumed that one and only one of the inflield replacements SRU will have failed. If there is a spare SRU in the existing stock, it is installed to the LRU to complete the repair. The base level has a certain probability of repairing the SRU, if the SRU can not be repaired, the SRU is sent to the relay level, and meanwhile, an order application of the SRU is made to the relay level. The relay-level and base-level processes are the same, and the specific process is shown in fig. 5.

For example, assume that the warehouse has three levels: the system comprises a base level, a relay level and a base level, wherein the spare part level comprises two levels, the aircraft is stopped due to the shortage of the LRU, and the LRU repair is delayed due to the shortage of the SRU; the requirements of different types of replaceable units on spare parts are mutually independent; spare parts can only apply for gradual supply step by step, and are not supplied from an indirect higher stage, and transverse supply among the same stages is not considered; the spare part protection system is in a stable state; the maintenance channels of all the sites are unlimited, the fault parts cannot be in queue for maintenance because the maintenance channels are occupied, and whether the LRU is maintained at the base level is irrelevant to the inventory or the repair workload.

Illustratively, the spare part inventory countermeasure of each guarantee level is (S-1, S), namely, a one-for-one ordering strategy, namely, when a certain part on the equipment fails, the failed part is sent for repair immediately. If the part has spare parts, the spare parts are immediately replaced, if the spare parts do not exist, the equipment is stopped due to supply delay, the equipment is restarted after the fault parts are repaired and returned, and under the strategy, the initial stock is the current stock + the stock in repair or supply-the spare parts shortage.

Illustratively, the problem of disassembly and repair and spare part redundancy is not considered; in the process of fault part maintenance and spare part replenishment, the replenishment priority among guarantee stations and the maintenance priority among fault units are not considered, namely, a first-come first-supply and first-come first-maintenance supply strategy is adopted; the maintenance time of the fault pieces is independent; the shortage of different faulty units has the same impact on the availability of the equipment, i.e. the importance of all equipment components is the same.

For an exemplary calculation sequence of spare part requirements, see fig. 6.

In one possible implementation, the step 101 of determining an average annual demand of the repair base level to the outfield repair LRU includes:

by passing

Calculating the annual average demand of the repairable element base level to the LRU of the outfield repairable element; wherein i is the number of the repairable piece, the item number i of the LRU of the outer field repairable piece is 0, and the rest i represents the item number of the SRU of the inner field repairable piece; j represents a base level number, k represents a relay level number, and k is 0 corresponding to the base level; DC (direct current) _i Representing the ratio of the operation time of the repairable part i to the total operation time of the equipment system; RIP _i Representing the in-situ repair probability of the repairable part i; HW represents equipment average run time; z is a linear or branched member _i Representing the number of repairable parts i installed on the upper-level part; n is a radical of hydrogen _j The number of equipment sites used; MTBF (methyl tert-butyl ether) _i Representing the mean time to failure of the repairable element i; ROK _i And representing the false detection probability of the repairable part i, wherein the false detection probability is the probability that the part i is the cause of equipment failure.

In step 102, determining a fault isolation rate of the repairable part includes:

by passing

Calculating the fault isolation rate q of the repairable part; the failure isolation rate indicates the ratio of the number of failures detected in a predetermined method to the number of failures detected in the same time, wherein g is the number of the component of the previous layer of the repairable part i, MTBF, and the number of failures detected in the same time, and the detected failure of the equipment component g is correctly isolated in a predetermined time by a predetermined method _g Indicating mean time to failure, RIP, of the component g _g Representing the in-situ repair probability of the part g; ROK (remote Ok) _g Indicating the false detection probability of the component g.

In step 103, an average annual demand of spare parts of each stage of the repairable part is determined based on the average annual demand of the repairable part base level to the LRUs of the outfield repairable part and the fault isolation rate of the repairable part.

Specifically, determining the annual average demand of each grade spare part of the repairable part comprises the following steps: determining the average annual demand of the repairable element base level on the SRU; determining the annual average demand of the repairable relay stage on the SRUs and the LRUs; an annual average demand on the SRUs and LRUs by the repairable ground level is determined.

For example, determining the average annual demand of the repairable base level for the SRU includes:

by passing

m _ij ＝m _0j ·r _0j ·q _ij (3)

Calculating the average annual demand of the base level on the SRU;

determining an average annual demand of the repairable relay stage for the SRUs and LRUs, comprising:

by passing

Calculating the annual average demand of the repairable relay level on the LRU;

by passing

Calculating the average annual demand of the repairable relay level on the SRU;

determining an annual average demand on the SRUs and LRUs by the repairable ground level, comprising:

by passing

Calculating the annual average demand of the repairable element base level to the LRU;

by passing

Calculating the average annual demand of the repairable element-based ground level on the SRU; wherein r is _0j Probability of defective parts for LRU being repairable at base level, r _ij Probability that a failed component that is an SRU can be repaired at the base level;r _0k probability that fault pieces of the LRU can be repaired at the relay level k; r is _ik Probability that a failed component that is an SRU can be repaired at relay level k.

In step 104, the number of supply channels at each level is determined based on the annual average demand for spare parts at each level of repairable parts.

Illustratively, the supply channel inventory consists essentially of two parts: the number of spare parts under repair and delivery, and the number of spare parts being replenished.

Specifically, determining the number of the supply channel reserves at each stage comprises the following steps: determining supply channel spare part number expectation and variance of the base-level LRU; the supply channel spare number of the base-level LRU comprises: when there is no SRU delay, the number of LRU of base-level service channel and the number of LRU of base-level service channel delayed because there is no SRU in base-level stock; determining the supply channel spare part number expectation and variance of the SRU and the LRU of the relay stage; the number of supply channel spares for the relay stage SRU includes: the number of the SRUs under repair and delivery for repair, and the number of delays caused by no SRU backup at the base level; the number of supply channel spare parts of the trunk-stage LRU includes: the number of LRU when there is no shortage, the number of delays due to no SRU backup in the relay stage, and the number of LRU repair delays due to base LRU shortage; determining supply channel spare part number expectation and variance of the base level SRU and the LRU; the number of supply channel spares for the base level SRU includes: the number of the SRUs under repair and service and the number of delays caused by the fact that no SRU backup exists in the relay level; the number of supply channel spares for the base level SRU includes: the number of LRUs without shortages, the number of LRU repair delays due to lack of SRU backups at the base level, and the number of LRU repair delays due to LRU shortages at the trunk level.

Illustratively, determining the spare part count expectation and variance of the base supply channel LRU includes:

by passing

ρ ₀₀ ＝m ₀₀ ·q _i0 /m _i0 (8)

Calculating the proportion of SRU (simplified request Unit) requirements generated by LRU (least recently used) repair to the total number of the SRU requirements at the base level;

by passing

Calculating the supply channel spare part number expectation of the base-level LRU;

by passing

And calculating the supply channel spare part number variance of the base-level LRU.

Illustratively, determining supply channel spare part number expectations and variances for the trunk SRUs and LRUs includes:

by passing

f _ik ＝m _ik (1-r _ik )/m _i0 (11)

Calculating the proportion of the SRU requirement generated by the shortage of the relay-level SRU to the total number of the base-ground-level SRU requirements;

by passing

E[X _ik ]＝m _ik ·[(1-r _ik )t _ik +r _ik T _ik ]+f _ik ·EBO(s _i0 |m _i0 T _i0 ) (12)

Calculating the supply channel spare part number expectation of the relay stage SRU; by passing

Var[X _ik ]＝m _ik ·[(1-r _ik )t _ik +r _ik T _ik ]+f _ik ·(1-f _ik )·EB0(s _i0 |m _i0 ·T _i0 )+f ² _ik .VBO(s _i0 |m _i0 ·T _i0 ) (13)

Calculating the variance of the number of spare parts of a supply channel of the SRU;

by passing

ρ _0k ＝m _0k ·q _ik ·r _0k /m _ik (14)

Calculating the ratio of the SRU requirement to the total SRU requirement generated by LRU repair;

by passing

f _0k ＝m _0k (1-r _0k )/m ₀₀ (15)

Calculating the proportion of the LRU demand generated by the shortage of the relay LRU to the total number of the ground-level LRU demand;

by passing

Calculating the supply channel spare part number expectation of the relay LRU;

by passing

And calculating the supply channel spare part number variance of the LRU at the relay level.

Illustratively, determining supply channel spare part number expectations and variances for base level SRUs and LRUs includes:

by passing

f _ij ＝m _ij (1-r _ij )/m _ik (18)

Calculating the proportion of the SRU requirement generated by the shortage of the base-level SRUs to the total number of the SRUs of the relay level;

by passing

E[X _ij ]＝m _ij ·[(1-r _ij )t _ij +r _ij T _ij ]+f _ij ·EBO(s _ik |m _ik T _ik ) (19)

Calculating the supply channel spare part number expectation of the base level SRU;

by passing

Var[X _ij ]＝m _ij ·[(1-r _ij )t _ij +r _ij T _ij ]+f _ij ·(1-f _ij )·EBO(s _ik |m _ik ·T _ik )+f ² _ij ·VBO(s _ik |m _ik T _ik ) (20)

Calculating the variance of the number of spare parts of the supply channel of the base level SRU;

by passing

f _0j ＝m _0j (1-r _0j )/m _0k (21)

Calculating the proportion of the LRU requirement generated by the shortage of the base-level LRU to the total number of the relay-level LRU requirement;

by passing

Calculating the supply channel spare part number expectation of the base level LRU;

by passing

And calculating the supply channel spare part number variance of the base level LRU.

Wherein EBO () is the expected shortage number of each stage of spare parts, VBO () is the variance of the shortage number of each stage of spare parts, T ₀₀ Mean repair time, T, for LRU for base level _i0 Average repair time to SRUs for base grade; t is _0k Average repair time to LRU for a relay level; t is _ik Average repair time to SRUs for relay level; t is _0j Average repair time to LRU for base level; t is _ij Average repair time to SRU for base level; t is t _ik Average delay time from applying for the relay stage to the base stage to delivering the SRU; t is t _0k The average delay time from applying to the base level for the relay level to delivering the LRU; t is t _ij Applying for the base level to the relay level for the average latency to deliver the SRU; t is t _0j The base level applies for the relay level for the average latency to delivery of the LRUs.

In step 105, a spare part inventory optimization model is established based on the spare part number optimization objective of each level of supply channel.

Illustratively, the model constraint is that the system availability is highest with the lowest total cost, and the system availability is defined as the expected value of the percentage of the number of equipment that is not shut down by any spare parts.

Specifically, the optimization objective includes: seeking equipment availability; seeking a maximum for equipment availability is equivalent to seeking a minimum for the sum of base-level LRU shortages.

Availability of said equipment formed by base level LRU and SRU can be obtained

Calculating; n is a radical of _j Number of equipment at base level, Z ₀ Is the number of LRUs in one equipment, i.e., the number of stand-alone installations.

If an equipment consists of N LRUs, any LRU failure causes the equipment to fail, so the equipment availability, consisting of N LRUs, is:

for all the guaranteed sites, the system availability is:

illustratively, because of the specificity of the system, the outage penalty is large, so the present application uses the availability as a constraint and tries to optimize its cost.

Specifically, establishing a spare part inventory optimization model includes:

in ensuring the availability of the system target A _m On the premise of minimizing the spare part cost of the system, the established spare part inventory optimization model is as follows:

A _x ≥A _m (28)

wherein C is _i Is the unit price of the spare part i; s. the _ij The inventory of the ith spare part of the jth security station.

Illustratively, the marginal optimization algorithm is the most commonly used algorithm for solving the multi-level inventory optimization problem, and is widely used at present. Marginal optimization achieves reasonable utilization of effective resources through balance analysis of cost-to-efficiency ratio, namely benefit and cost of marginal units. The cost-to-efficiency ratio is defined as the ratio of the reduction value of the adjacent expected shortage number to the corresponding spare part cost, namely:

the main idea of marginal analysis is that only one spare part is added in the algorithm each time, and the spare part added is judged to have the largest influence on the marginal benefit, namely the cost-benefit ratio is the largest, the number of the largest spare parts is correspondingly increased by one, and the others are kept unchanged. And the like until the cost is not enough to buy the next spare part. At this time, the total shortage number of the equipment spare parts is the sum of the EBOs corresponding to each spare part.

The specific marginal optimization algorithm for establishing the spare part inventory optimization model comprises the following steps:

the first step is as follows: initializing the number of system spare parts, order S _ij ＝0。

The second step is that: performing algorithm iteration, and calculating the marginal benefit epsilon of each spare part in each step of iteration process _ij The calculation formula is as follows:

the third step: determining epsilon _ij The maximum corresponds to the spare part and the number is increased by 1.

The fourth step: according to the stock quantity S of spare parts _ij Availability of bonded systems A _x If A is _x Reach the target availability A of the system _m Then the algorithm iteration is finished to obtain S _ij Matrix for optimal inventory of spare partsA scheme; otherwise, the second step is entered to continue the execution of the algorithm. The above-mentioned marginal optimization algorithm flow is shown in fig. 8.

It should be understood that, the sequence numbers of the above steps do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

Fig. 9 shows a structural block diagram of a repairable item multi-level inventory optimization device provided in the embodiment of the present application, corresponding to the repairable item multi-level inventory optimization method described in the above embodiment, and for convenience of description, only the parts related to the embodiment of the present application are shown.

Referring to fig. 9, the repairable item multi-level inventory optimization apparatus in the embodiment of the present application may include a first determination module 201, a second determination module 202, a third determination module 203, a fourth determination module 204, and an optimization module 205.

The first determining module 201 is configured to determine, based on the relevant data of the equipment and the repairable part, an average required quantity of spare parts at each level of the repairable part;

a second determining module 202, configured to determine a fault isolation rate of the repairable element;

a third determining module 203, configured to determine an annual average demand of each stage of spare parts of the repairable part based on the average demand of each stage of spare parts and the fault isolation rate;

a fourth determining module 204, configured to determine the number of spare parts in each level of supply channels based on the annual average demand of each level of spare parts of repairable parts; the number of supply channel spare parts at each level includes: the number of spare parts under repair and delivery and the number of spare parts being replenished;

and the optimization module 205 is used for optimizing the target and establishing a spare part inventory optimization model based on the spare part number of each level of supply channel.

It should be noted that, for the information interaction, the execution process, and other contents between the above-mentioned apparatuses, the specific functions and the technical effects of the embodiments of the method of the present application are based on the same concept, and specific reference may be made to the section of the embodiments of the method, which is not described herein again.

It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-mentioned division of the functional units and modules is illustrated, and in practical applications, the above-mentioned function distribution may be performed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-mentioned functions. Each functional unit and module in the embodiments may be integrated in one processing unit, or each unit may exist alone physically, or two or more units are integrated in one unit, and the integrated unit may be implemented in a form of hardware, or in a form of software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. For the specific working processes of the units and modules in the system, reference may be made to the corresponding processes in the foregoing method embodiments, which are not described herein again.

An embodiment of the present application further provides a terminal device, and referring to fig. 10, the terminal device 300 may include: at least one processor 310 and a memory 320, wherein the memory 320 stores a computer program operable on the at least one processor 310, and the processor 310 executes the computer program to implement the steps of any of the method embodiments described above, such as the steps 101 to 105 in the embodiment shown in fig. 1. Alternatively, the processor 310, when executing the computer program, implements the functions of the modules/units in the device embodiments, such as the functions of the modules 201 to 205 shown in fig. 9.

Illustratively, the computer program may be divided into one or more modules/units, which are stored in the memory 320 and executed by the processor 310 to accomplish the present application. The one or more modules/units may be a series of computer program segments capable of performing specific functions, which are used to describe the execution of the computer program in the terminal device 300.

Those skilled in the art will appreciate that fig. 10 is merely an example of a terminal device and is not limiting and may include more or fewer components than shown, or some components may be combined, or different components such as input output devices, network access devices, buses, etc.

The Processor 310 may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic device, discrete hardware component, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The memory 320 may be an internal storage unit of the terminal device, or may be an external storage device of the terminal device, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), and the like. The memory 320 is used for storing the computer programs and other programs and data required by the terminal device. The memory 320 may also be used to temporarily store data that has been output or is to be output.

The bus may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended ISA (EISA) bus, or the like. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, the buses in the figures of the present application are not limited to only one bus or one type of bus.

The repairable piece multilevel inventory optimization method provided by the embodiment of the application can be applied to terminal equipment such as a computer, a tablet computer, a notebook computer, a netbook, a Personal Digital Assistant (PDA) and the like, and the specific type of the terminal equipment is not limited at all by the embodiment of the application.

Embodiments of the present application further provide a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, the computer program implements the steps in the foregoing repairable piece multi-level inventory optimization method.

The embodiment of the application provides a computer program product, and when the computer program product runs on a mobile terminal, the steps in each embodiment of the repairable part multi-level inventory optimization method can be realized when the mobile terminal is executed.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, all or part of the processes in the methods of the embodiments described above can be implemented by a computer program, which can be stored in a computer-readable storage medium and can implement the steps of the embodiments of the methods described above when the computer program is executed by a processor. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer readable medium may include at least: any entity or device capable of carrying computer program code to a photographing apparatus/terminal apparatus, a recording medium, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), an electrical carrier signal, a telecommunications signal, and a software distribution medium. Such as a usb-drive, a removable hard drive, a magnetic or optical disk, etc. In some jurisdictions, computer-readable media may not be an electrical carrier signal or a telecommunications signal in accordance with legislative and proprietary practices.

In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the embodiments provided in the present application, it should be understood that the disclosed apparatus/network device and method may be implemented in other ways. For example, the above-described apparatus/network device embodiments are merely illustrative, and for example, the division of the modules or units is only one logical division, and there may be other divisions when actually implementing, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not implemented. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.

Claims (10)

1. A repairable piece multi-level inventory optimization method, comprising:

determining an average annual demand of the repairable base level for the outfield repairable LRU based on the associated data of equipment and repairable pieces;

determining a fault isolation rate of the repairable piece;

determining the annual average demand of spare parts of each stage of the repairable part based on the annual average demand of the repairable part base level to the LRU of the outfield repairable part and the fault isolation rate of the repairable part;

determining the spare parts number of each stage of supply channel based on the annual average demand of each stage of spare parts of the repairable part;

and establishing a spare part inventory optimization model based on the spare part number optimization target of each level of supply channel.

2. The repairable item multi-level inventory optimization method of claim 1, wherein the repairable items include an outfield repairable item LRU and an outfield repairable item SRU; the outfield repairable LRU is a component removed from the equipment, and the outfield repairable SRU is a component of the outfield repairable LRU.

3. The repairable item multi-level inventory optimization method of claim 1, wherein said determining an average annual demand of said repairable item base level on outfield repairable item LRU comprises:

by passing

Calculating the annual average demand of the repairable part base level to the outfield repairable part LRU;

wherein i is the number of the repairable piece, the item number i of the LRU of the outer field repairable piece is 0, and the rest i represents the item number of the SRU of the inner field repairable piece; j represents a base level number, k represents a relay level number, and k is 0 corresponding to the base level; DC (direct current) _i Representing the ratio of the operation time of the repairable part i to the total operation time of the equipment system; RIP _i Representing the in-situ repair probability of the repairable part i; HW represents equipment average run time; z _i Indicating the number of repairable elements i installed on the upper level part；N _j The number of equipment sites used; MTBF (methyl tert-butyl ether) _i Representing mean time to failure of repairable item i; ROK _i And representing the false detection probability of the repairable part i, wherein the false detection probability is the probability that the part i is the cause of equipment failure.

4. The repairable item multi-level inventory optimization method of claim 3, wherein the determining a fault isolation rate for the repairable item comprises:

by passing

Calculating the fault isolation rate q of the repairable part;

the fault isolation rate indicates the ratio of the number of faults detected in the equipment component g to be not more than a specified ambiguity and the number of faults detected in the same time, wherein g is the number of the component in the next layer above the repairable part i, MTBF, and the detected fault isolation rate is correctly isolated in a specified time by a specified method _g Indicating mean time to failure, RIP, of the component g _g Representing the in-situ repair probability of the part g; ROK (remote Ok) _g Indicating the false detection probability of the component g.

5. The repairable part multi-level inventory optimization method of claim 4, wherein the determining the annual average demand for each level of spare parts of the repairable part comprises:

determining an average annual demand of the repairable element base level for an infield repairable element SRU;

determining the average annual demand of the repairable relay stage on the interior repairable SRU and the exterior repairable LRU;

determining the average annual demand of the repairable element base level for the inner field repairable element SRU and the outer field repairable element LRU;

the determining an average annual demand of the repairable element base level for infield repairable element SRUs comprises:

by passing

m _ij ＝m _0j ·r _0j ·q _ij

Calculating the average annual demand of the repairable element base level on the internal field repairable element SRU;

said determining an average annual demand of said repair relay stage for inlield repair SRUs and outlay repair LRUs comprising:

by passing

Calculating the average annual demand of the repairable piece relay level to the outfield repairable piece LRU;

by passing

Calculating the average annual demand of the repairable piece relay level on the internal field repairable piece SRU;

the determining an average annual demand of the repairable base level for the interior field repairable SRU and the exterior field repairable LRU comprises:

by passing

Calculating the annual average demand of the repairable element base level to the outfield repairable element LRU;

by passing

Calculating the average annual demand of the repairable element base level on the internal field repairable element SRU;

wherein r is _0j Probability r of a failed item of the outfield repairable item LRU being repairable at the base level _ij Failed components for infield repairable SRUs can be at the base levelThe probability of repair; r is _0k Probability that fault parts of the LRU can be repaired at the relay level k; r is _ik Probability that a failed component, which is an infield repairable component SRU, can be repaired at relay level k.

6. The repairable item multi-level inventory optimization method of claim 5, wherein said determining the number of supply channel inventory levels at each level comprises:

determining the supply channel spare part number expectation and variance of the base-level outfield repairable part LRU; the supply channel spare part number of the base-level outfield repairable part LRU comprises: when there is no delay of the internal field repairable piece SRU, the number of the external field repairable piece LRUs of the base-level delivery channel and the number of the delayed base-level delivery external field repairable piece LRUs due to the fact that the base-level current inventory does not have the required internal field repairable piece SRU;

determining supply channel spare part number expectation and variance of the trunk-level inside field repaired parts SRU and outside field repaired parts LRU; the supply channel spare part number of the field repairable part SRU in the relay stage comprises the following steps: the number of the internal field repairable SRUs repaired and sent for repair, and the number of delays caused by the fact that no internal field repairable SRU backup exists at the base level; the supply channel spare parts number of the trunk-level outfield repairable part LRU comprises: the number of LRUs of the external field repairable elements when the number of LRUs is not in shortage, the number of delays caused by the fact that the relay level does not have SRU backup of the internal field repairable elements, and the number of LRUs of the external field repairable elements caused by the shortage of LRUs of the base external field repairable elements;

determining supply channel spare part number expectations and variances for the base level infield repairable SRUs and the outfield repairable LRUs; the supply channel spare part number of the base-level infield repairable part SRU comprises: the number of the repaired and sent-to-repair inner field repairable SRUs and the number of delays caused by the fact that no inner field repairable SRU backup exists at the relay level; the supply channel spare part number of the base-level infield repairable part SRU comprises: the number of out field repairable LRUs when there is no shortage, the number of delays due to no backup of the base level with the inner field repairable SRUs, and the number of out field repairable LRU repair delays due to the shortage of the trunk level LRUs;

the determining the expectation and variance of spare part number of the LRU of the outfield repairable part of the base supply channel comprises the following steps:

by passing

ρ ₀₀ ＝m ₀₀ ·q _i0 /m _i0

Calculating the proportion of the inner field repairable SRU requirement generated by the LRU repair of the outer field repairable element to the total number of the inner field repairable SRU requirements of the base level;

by passing

Calculating the supply channel spare part number expectation of the LRU of the base-level outfield repairable part;

by passing

Calculating the supply channel spare part number variance of the LRU of the base-level outfield repairable part;

the determining supply channel spare part number expectation and variance of the intra-field repairable part SRU and the extra-field repairable part LRU of the relay stage comprises:

by passing

f _ik ＝m _ik (1-r _ik )/m _i0

Calculating the proportion of the demand of the interior field repairable SRU generated by the shortage of the relay interior field repairable SRU to the total demand of the base interior field repairable SRU;

by passing

E[X _ik ]＝m _ik ·[(1-r _ik )t _ik +r _ik T _ik ]+f _ik ·EBO(s _i0 |m _i0 T _i0 )

Calculating the supply channel spare part number expectation of the field repairable part SRU in the relay level;

by passing

Var[X _ik ]＝m _ik ·[(1-r _ik )t _ik +r _ik T _ik ]+f _ik ·(1-f _ik )·EB0(s _i0 |m _i0 ·T _i0 )+f ² _ik ·VBO(s _i0 |m _i0 ·T _i0 )；

Calculating the supply channel spare part number variance of the relay level infield repairable part SRU;

by passing

ρ _0k ＝m _0k ·q _ik ·r _0k /m _ik

Calculating the proportion of the inner field repairable SRU requirement generated by LRU repair to the total number of the inner field repairable SRU requirements;

by passing

f _0k ＝m _0k (1-r _0k )/m ₀₀

Calculating the proportion of the LRU demand of the repaired outside field to the total LRU demand of the repaired outside field of the base level, which is generated by the shortage of the repaired LRU outside field of the relay level;

by passing

Calculating the supply channel spare part number expectation of the LRU of the relay class outfield repairable part;

by passing

Calculating the supply channel spare part number variance of the LRU of the relay level outfield repairable part;

the determining supply channel spare part number expectations and variances for the base level infield and outfield repairable element SRUs and LRUs comprises:

by passing

f _ij ＝m _ij (1-r _ij )/m _ik

Calculating the proportion of the inner field repairable SRU requirement generated by the shortage of the inner field repairable SRUs at the base level to the total number of the inner field repairable SRUs at the relay level;

by passing

E[X _ij ]＝m _ij ·[(1-r _ij )t _ij +r _ij T _ij ]+f _ij ·EBO(s _ik |m _ik T _ik )

Calculating the supply channel spare part number expectation of the field repairable part SRU in the base level;

by passing

Var[X _ij ]＝m _ij ·[(1-r _ij )t _ij +r _ij T _ij ]+f _ij ·(1-f _ij )·EBO(s _ik |m _ik ·T _ik )+f ² _ij ·VBO(s _ik |m _ik T _ik )

Calculating the supply channel spare part number variance of the field repairable part SRU in the base level;

by passing

f _0j ＝m _0j (1-r _0j )/m _0k

Calculating the proportion of the LRU demand of the external field repairable parts generated by the shortage of the base-level external field repairable parts to the total LRU demand of the relay-level external field repairable parts;

by passing

Calculating a supply channel spare part number expectation of the base-level outfield repairable part LRU;

by passing

Calculating the supply channel spare part number variance of the base level outfield repairable part LRU;

wherein EBO () is the expected shortage number of each stage of spare parts, VBO () is the variance of shortage number of each stage of spare parts, T ₀₀ Mean repair time for LRU for base level, T _i0 Average repair time for the base level to the infield repairable SRU; t is _0k Average repair time to LRU for a relay level; t is _ik For relay class to infield repairable SRAverage repair time of U; t is _0j Average repair time for outfield repairable LRU for the base level; t is _ij Average repair time for the base level to the infield repairable SRU; t is t _ik The average delay time from the relay stage applying to the base stage to delivering the interior field repairable piece SRU; t is t _0k The average delay time from the relay to the base to the delivery of the LRU of the field repairable part; t is t _ij Applying for the average delay time from the base level to the relay level to the delivery of the infield repairable piece SRU; t is t _0j Applying for the average delay time from the relay level to the delivery of the export repairable LRU for the base level; s _ij SRU inventory at base level; s _ik The SRU stock of the relay level; s is _0k LRU stock for the relay level; s _i0 The base level SRU inventory; s ₀₀ LRU inventory at base level; x _ij The number of supply channels for the infield repairable SRUs of the base level; x _0j The number of supply channels for the outfield repairable LRU of the base level; x _ik The number of supply channels for the relay-level infield repairable SRUs; x _0k The number of supply channels of the LRU for the outfield repairable part of the relay level; x ₀₀ The number of supply channels for the outfield repairable LRU at base level.

7. The repairable item multi-level inventory optimization method of claim 1, wherein the optimization objective includes:

seeking equipment availability; said maximum seeking equipment availability is equivalent to a minimum seeking the sum of said base-level LRU shortages;

availability of said equipment formed by LRU and SRU of said base level

Calculating; n is a radical of hydrogen _j Number of equipment at base level, Z ₀ Is the number of LRUs in one equipment, i.e. the number of single machine installations;

assuming that said equipment consists of N of said LRUs, any failure of said LRUs results in a failure of said equipment, and therefore the equipment availability consisting of N of said LRUs is:

for all the guaranteed sites, the system availability is:

8. the repairable part multi-level inventory optimization method of claim 7, wherein the establishing a spare part inventory optimization model comprises:

in ensuring the availability of the system target A _m On the premise of minimizing the spare part cost of the system, the established spare part inventory optimization model is as follows:

A _x ≥A _m

wherein C is _i Is the unit price of the spare part i; s _ij The inventory of the ith spare part of the jth guarantee site.

9. The repairable part multi-level inventory optimization method of claim 8, wherein the marginal optimization algorithm used for establishing the spare part inventory optimization model comprises the following steps:

the first step is as follows: initializing the number of system spare parts, order S _ij ＝0；

The second step is that: performing algorithm iteration, and calculating the marginal benefit epsilon of each spare part in each step of iteration process _ij The calculation formula is as follows:

the third step: determining epsilon _ij Adding 1 to the spare parts corresponding to the maximum value;

the fourth step: according to the stock quantity S of the spare parts _ij In combination with said system availability A _x If A is _x Achieving the system target availability A _m Then the algorithm iteration is finished to obtain S _ij The matrix is an optimal inventory scheme of spare parts; otherwise, go to the second step.

10. A repairable piece multi-level inventory optimization device, comprising:

the first determining module is used for determining the average demand of each level of spare parts of the repairable part based on the relevant data of the equipment and the repairable part;

the second determination module is used for determining the fault isolation rate of the repairable part;

the third determining module is used for determining annual average demand of each level of spare parts of the repairable part based on the average demand of each level of spare parts and the fault isolation rate;

the fourth determining module is used for determining the spare part number of each level of supply channel based on the annual average demand of each level of spare parts of the repairable part; the number of the supply channel spare parts at each level comprises: the number of spare parts under repair and delivery and the number of spare parts being replenished;

and the optimization module is used for optimizing the target and establishing a spare part inventory optimization model based on the spare part number of each level of supply channel.

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