Maintenance management method and maintenance management system

Abstract

To provide a maintenance management method capable of predicting future wear of a caster during long-distance runs based on test results of small mileage of the caster, and a maintenance management system.SOLUTION: The maintenance management method includes the steps of: carrying out a running test of a caster by changing the test conditions including the load, the type of caster, and the type of floor surface; measuring the wear amount of the caster and calculating the relational expression between the wear amount and the travel distance based on the obtained measurement value; calculating the future wear amount of the caster provided on a moving body based on the relational expression; and generating a maintenance plan for the moving body based on the calculated future wear amount.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a maintenance management method and a maintenance management system. [Background technology]

[0002] With the expansion of mail order business in recent years, large-scale logistics warehouses need to move a large number of items in a short time. For this reason, automatic guided vehicles (hereinafter referred to as AGVs) that automatically transport items have been used in logistics-related facilities such as large-scale logistics warehouses. For example, 2 In large logistics warehouses exceeding 10,000m in size, hundreds of AGVs operate almost non-stop, 24 hours a day, except for scheduled maintenance periods. Each AGV can travel several thousand kilometers per month, and in some cases, more than 10,000 kilometers per year.

[0003] The surface of AGV casters is made of resin materials such as nylon and urethane. Casters are made in various types, including different hardness and shapes. The amount of caster wear varies depending on the conditions of AGV use. The longer the travel distance, the greater the wear on the casters, and the harder the caster material, the less wear there is relative to the travel distance. To reduce caster wear, select casters made of a hard material. However, if casters made of a hard material are selected, the vibration transmitted to the AGV will increase and there is a risk of increased damage to the slab (floor) surface.

[0004] Furthermore, while using casters made of soft materials reduces vibration transmitted to the AGV, it may increase wear and the need for frequent replacement. Therefore, when selecting casters, it is desirable to have test data for various combinations that replicate the AGV's operating conditions in advance. However, as mentioned above, an AGV in operation travels several thousand kilometers per month, and verifying the performance through reproducible testing of many combinations requires time and effort. For example, assuming a 50 cm (25 cm) caster repeat run test using a 30 cm long concrete specimen, 1 km requires 2,000 run runs, and 100 km requires 200,000 run runs. Assuming one run takes 10 seconds, running 100 km would take approximately 23 days. Taking into account measurements and equipment maintenance along the way, the test would take approximately one month.

[0005] For example, Patent Document 1 describes a method for detecting wheel abnormalities based on measurements of the amount of wear on the wheels of a railway vehicle. Patent Document 2 describes a method for predicting the state of wheel wear based on measurements of the amount of wear on the wheels of a railway vehicle. Patent Document 3 describes a method for estimating the amount of wear on casters of an automated guided vehicle based on detected values ​​of the number of rotations and linear travel distance of the casters and the initial value of the diameter of the casters. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2021-043148 [Patent Document 2] Japanese Patent Publication No. 2020-183767 [Patent Document 3] Japanese Patent Application Laid-Open No. 2007-022282 Summary of the Invention [Problem to be solved by the invention]

[0007] During regular maintenance, AGVs replace casters that have worn beyond the standard. Therefore, in operations that use AGVs, it is desirable to monitor the condition of casters, which are routinely replaced parts, predict when they will be replaced due to wear, and create future maintenance plans that forecast order quantities and inventory levels.

[0008] The methods described in Patent Documents 1 and 2 detect wheel abnormalities and wear based on the relationship between the rail and the wheels, and when applied to AGVs, it is necessary to change the application conditions, such as different floor conditions and different wheel types.The method described in Patent Document 3 estimates the current amount of wear on the casters of an AGV, but does not grasp the amount of wear in the future.

[0009] The present invention aims to provide a maintenance management method and a maintenance management system that predict the future wear amount of a caster when traveling long distances based on test results in which the caster has traveled a short distance. [Means for solving the problem]

[0010] One aspect of the present invention is a maintenance management method comprising the steps of: conducting a running test of a mobile body on which casters are installed by changing test conditions including the applied load, the type of caster, and the type of floor surface; measuring the amount of wear of the casters and calculating a relationship between the amount of wear and the running distance based on the obtained measured values; calculating the future amount of wear of the casters installed on the mobile body while it is in operation based on the relationship; and generating a maintenance plan for the mobile body based on the calculated future amount of wear.

[0011] According to the present invention, by obtaining measurement values ​​based on caster wear tests, the amount of wear of the caster 10 over a long travel distance can be predicted based on a short travel distance, thereby significantly reducing measurement time and labor.

[0012] Furthermore, the relational equation of the present invention may be an approximation that linearly represents the relationship between the logarithm of the travel distance of the moving body based on the test conditions and the logarithm of the amount of wear of the caster, and may include a step of calculating parameters in the relational equation based on the measured values.

[0013] According to the present invention, the future wear amount of the caster can be easily calculated by regressing the relationship between the travel distance of the caster and the wear amount into a simple linear equation.

[0014] The present invention may also include a step of accumulating test results of the running tests based on different test conditions, a step of periodically measuring the amount of operating wear of the casters provided on the operating moving body, and a step of adjusting the parameters based on the test results and the measured values ​​of the amount of operating wear.

[0015] According to the present invention, by measuring the amount of wear on the casters of a moving object that has actually been driven at a predetermined timing in addition to the results of the running test, it is possible to adjust the parameters of the calculated relational equation and improve the accuracy of the predicted value.

[0016] The present invention may also include a step of conducting a running test of the caster for which information on the type is insufficient, and a step of estimating the type of the caster based on the test results.

[0017] According to the present invention, even when there is little information about a caster, a running test can be performed, measurement values ​​can be obtained, and the measurement values ​​can be compared with the measurement values ​​of other casters, thereby making it possible to estimate the type of caster based on similar data.

[0018] The present invention may also include a step of designing a new caster based on the test results and the amount of operational wear.

[0019] According to the present invention, the database of test results can be used to develop new caster products that are suited to conditions of use such as the method of use and the place of use.

[0020] One aspect of the present invention is a maintenance management system having a calculation unit that calculates a relationship between the amount of wear and the distance traveled based on measured values ​​of the amount of wear of the casters obtained through running tests of a mobile body on which the casters are installed, where the running tests are conducted under different test conditions including the applied load, the type of caster, and the type of floor surface, calculates the future amount of wear of the casters installed on the mobile body while it is in operation based on the relationship, and generates a maintenance plan for the mobile body based on the calculated future amount of wear.

[0021] According to the present invention, by obtaining measurement values ​​based on caster wear tests, the amount of wear of the caster 10 over a long travel distance can be predicted based on a short travel distance, thereby significantly reducing measurement time and labor. [Effects of the Invention]

[0022] According to the present invention, it is possible to estimate the future amount of wear of casters provided on a moving body. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a diagram showing a configuration of a test device according to an embodiment of the present invention; [Figure 2] FIG. 1 is a block diagram showing the configuration of a maintenance management system. [Figure 3] FIG. 10 is a diagram showing the relationship between the travel distance of a caster and the amount of wear. [Figure 4] FIG. 10 is a diagram showing the relationship between the travel distance of a caster and the amount of wear by an approximation formula. [Figure 5] FIG. 10 is a diagram showing the relationship between the logarithm of the travel distance of a caster and the logarithm of the wear amount. [Figure 6] 1 is a flowchart showing the flow of each step of a maintenance management method. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of a maintenance management method and a maintenance management system according to the present invention will be described with reference to the drawings. The maintenance management system supports a periodic maintenance plan for casters of an AGV (mobile vehicle) based on the maintenance management method.

[0025] As shown in Fig. 1, a running test is performed on a caster 10 used in an AGV using a testing device 100. In the testing device 100, a running test is performed in which the running of an AGV equipped with casters is reproduced by changing test conditions including, for example, the load, the type of caster 10, and the type of floor surface. In the running test, the running of the AGV is reproduced and the amount of wear on the caster 10 equipped on the AGV is periodically measured.

[0026] The test device 100 includes, for example, a test stand 101 on which the caster 10 is placed, a running device 102 that causes the caster 10 to run back and forth on the test stand 101, a loading device 103 that applies a load to the caster 10, and a measuring device 104 connected to the running device 102. The test stand 101 has, for example, a test object formed into a plate shape using the same material as the floor material on its surface. The running device 102 is, for example, a device that applies a reciprocating motion to the caster 10 based on a rotational motion. The running device 102 causes the caster 10 to reciprocate once with one rotation of the rotor 102R, for example.

[0027] The rotor 102R is provided with a link device 102L having a plurality of link rods. The travel device 102 has a stroke amount adjusted so that one reciprocation is 50 cm. The loading device 103 applies a load to the caster 10 from above using, for example, a weight. The configuration of the testing device 100 described above is one example, and any device configuration may be used as long as it is capable of measuring the amount of wear of the caster 10.

[0028] The measuring device 104, for example, detects the detection value of an encoder 102A that detects the number of rotations provided on the traveling device 102, calculates the travel distance of the caster 10 based on the detected value, and records the calculated value together with the time and the number of reciprocation movements. When the travel distance of the caster 10 reaches a predetermined distance or a predetermined number of reciprocation movements, the outer diameter of the caster 10 is measured. The outer diameter of the caster 10 may be measured using a measuring tool such as a micrometer or calipers, or may be calculated automatically based on the number of rotations of the caster 10 and the reciprocation distance after measuring the number of rotations.

[0029] The measurement device 104 is configured by an information processing device such as a personal computer, a tablet terminal, a smartphone, etc. The measurement device 104 may be a server device connected to a network W, which will be described later.

[0030] The test device 100 can be used to change test conditions, including the applied load, the type of caster 10, and the type of floor surface, to collect data indicating the degree of wear of the caster 10 under various conditions. The test data obtained from the running test is input into the maintenance management device 1 described below.

[0031] 2, the maintenance management device 1 is connected to a measuring device 104, for example, via a network W. The network W is configured, for example, by a public line, a LAN, a WAN, etc. The network W may also be configured by various types of lines, such as wired and wireless.

[0032] The maintenance management device 1 acquires test data from the measuring device 104, for example, via a network W. The maintenance management device 1 is configured, for example, by an information processing device such as a personal computer, a tablet terminal, or a smartphone. The maintenance management device 1 may be a server device connected to the network W. The maintenance management device 1 may be configured to operate in conjunction with the measuring device 104 on the network W, or may be configured integrally with the measuring device 104.

[0033] The maintenance management device 1 includes, for example, an acquisition unit 2 that acquires measurement data from a measuring device 104. The acquisition unit 2 is, for example, a communication interface that can send and receive data via a network W. The acquisition unit 2 stores the acquired data in a memory unit 4. The memory unit 4 is, for example, a non-temporary storage device configured with a hard disk drive (HDD), flash memory, etc. The measurement data stored in the memory unit 4 is read by a calculation unit 3 that executes various calculations.

[0034] The calculation unit 3 calculates a relational expression between the amount of wear and the distance traveled by the mobile object based on, for example, the measured value of the outer diameter of the caster 10. The calculation unit 3 calculates, for example, the future amount of wear of the caster 10 provided on the mobile object in operation based on the relational expression. The calculation unit 3 generates a maintenance plan for the AGV (mobile object) based on, for example, the calculated future amount of wear of the caster 10. The generated maintenance plan is displayed on the display unit 5. The display unit 5 is a display device configured, for example, by a liquid crystal display, an organic EL display, or the like. The calculation contents of the calculation unit 3 will be described below.

[0035] As shown in FIG. 3, the wear amount (mm) of the caster 10 increases as the travel distance (km) increases. The wear amount of the caster 10 also varies depending on the material of the caster 10. Under the same travel distance, the wear amount of the caster 10 is smaller when the caster 10 is made of a hard material such as a hard resin than when the caster 10 is made of a soft material such as a soft resin. At the predetermined reference value of the wear amount that requires replacement of the caster 10, when the caster 10 is made of a hard material, the travel distance is shorter than when the caster 10 is made of a soft material. As shown in the figure, the wear amount of the caster 10 increases in a curve with respect to the travel distance.

[0036] The amount of wear of the caster 10 actually measured by the test device 100 differs depending on the material of the caster 10. In the test, the amount of wear of two types of casters 10 (caster (1) and caster (2)) attached to the AGV was measured periodically. Caster (1) is made of, for example, a soft material. Caster (2) is made of, for example, a harder material than caster (1).

[0037] 4 shows an example of a graph in which the relationship between the travel distance (km) and the amount of wear (mm) of the caster 10 is approximated by a function based on the measured values. As shown in the figure, the approximated curve obtained is a power curve.

[0038] As shown in Figure 5, when the travel distance of the caster 10 on the horizontal axis and the wear amount of the caster 10 on the vertical axis are graphed as logarithmic values, the relationship between the travel distance of the caster 10 and the wear amount can be expressed as a straight line. As shown in the figure, the relationship between the travel distance of the caster 10 and the wear amount can be expressed based on a simple equation that is linearly regressed, such as Y = AX + B. By calculating the coefficient A and constant B in the linear relationship, the future wear amount of the caster 10 can be predicted.

[0039] Parameters such as coefficient A and constant B in the relational expression change depending on differences in running conditions such as the material, shape, load capacity, and type of floor test specimen of the caster 10. Therefore, by accumulating data on combinations of many different running conditions and creating a database, it is possible to obtain wear trends from short-term test data even for products for which accurate caster information is not available, such as overseas products.

[0040] That is, according to the maintenance management method, a relational expression for the caster 10 may be calculated based on test data for the caster 10 for which type information is insufficient, and a type similar to the caster 10 may be estimated based on the calculation results. According to the maintenance management method, a caster 10 for which type information is insufficient may be attached to an AGV and operated, the amount of operational wear of the caster 10 that wears during operation may be periodically measured, a relational expression for the caster 10 may be calculated based on the amount of operational wear, and a type similar to the caster 10 may be estimated based on the calculation results. Furthermore, when developing a caster 10 as a product, it is possible to predict trends based on this database, significantly reducing the testing time required to measure the amount of wear of the caster 10. According to the maintenance management method, a new caster may be designed based on the test results and the amount of operational wear.

[0041] Furthermore, finding the travel distance that corresponds to the reference value for wear amount while the test is being carried out is difficult to predict at the test planning stage. Therefore, by reflecting wear amount data obtained by actually running the AGV in the test database, the parameters in the relational equation can be adjusted, and wear amount trends can be more accurately grasped. In other words, in a maintenance management method, test results from running tests under different test conditions can be accumulated, the operating wear amount of the casters 10 attached to the operating AGV can be periodically measured, and the parameters included in the relational equation can be adjusted based on the test results and the measured operating wear amount.

[0042] The above-described caster 10 maintenance management method can be executed by a maintenance management device 1. In the maintenance management device 1, an acquisition unit 2 acquires measured values ​​of caster wear obtained through periodic running tests of a mobile object equipped with casters, which are conducted by changing test conditions including the applied load, the type of caster, and the type of floor surface. A calculation unit 3 calculates a relational expression between the amount of wear and the running distance of the mobile object based on the measured values. The relational expression is an approximation that expresses the relationship between the logarithm of the running distance of the mobile object based on the test conditions and the logarithm of the caster wear by linear regression. The calculation unit 3 calculates parameters in the relational expression based on the measured values.

[0043] The calculation unit 3 calculates the future wear amount of the casters attached to the moving body based on the relational expression. The calculation unit 3 may generate a maintenance plan for the casters 10 based on the calculated future wear amount. The maintenance plan determines the time when the outer diameter of the casters 10 will become equal to or smaller than a reference value based on a relational expression calculated based on, for example, the type of attached casters 10, the type of floor surface in the movable area, and the applied load, and indicates the time to replace the casters 10 of the AGV. The calculation unit 3 generates a maintenance plan for each AGV based on the operating status of each AGV. The maintenance plan may be updated based on actual measurements of the casters 10. The maintenance plan is displayed on the display unit 5 of the maintenance management device 1. The manager replaces the casters 10 attached to the AGV based on the maintenance plan.

[0044] Next, a maintenance management method for the caster 10 attached to the AGV will be described.

[0045] FIG. 7 is a flowchart showing the steps of a maintenance management method using the maintenance management system S. Using the test device 100, a running test is performed on an AGV equipped with the casters 10 by changing test conditions, including the applied load, the type of caster 10, and the type of floor surface (step S100). The maintenance management device 1 measures the amount of wear on the casters 10 at a predetermined timing and obtains a measurement value correlating the amount of wear with the travel distance of the casters 10 (step S102). The maintenance management device 1 calculates a relational expression between the amount of wear and the travel distance of the casters 10 based on the obtained measurement value (step S104). The maintenance management device 1 calculates the future amount of wear on the casters equipped on the operating mobile object based on the relational expression (step S106). The maintenance management device 1 generates a maintenance plan for the mobile object based on the calculated future amount of wear (step S108).

[0046] As described above, the maintenance management method allows for the prediction of the amount of wear of the caster 10 over long travel distances based on short travel distances in caster wear tests, significantly reducing measurement time and labor. The maintenance management method can be useful for understanding the wear trends of casters 10, for which information is scarce, such as imported products, based on a database of test results obtained from a wide variety of combinations of caster materials, shapes, and load capacities. The maintenance management method can also be used to develop new casters tailored to usage conditions, such as usage method and location, based on the test results database. When the caster 10 is installed on an actual AGV, the maintenance management method allows for the prediction of the amount of wear of the caster based on travel distance, and a maintenance plan can be generated that predicts the replacement period.

[0047] The calculation unit 3 is realized by a processor such as a central processing unit (CPU) or a graphics processing unit (GPU) executing a program (software). Some or all of these functional units may be realized by hardware such as a large-scale integration (LSI), an application-specific integrated circuit (ASIC), or a field-programmable gate array (FPGA), or may be realized by a combination of software and hardware. The program may be stored in a storage device such as a hard disk drive (HDD) or flash memory included in the storage unit 4, or may be stored in a removable storage medium such as a DVD or CD-ROM and installed in the storage device by inserting the storage medium into a drive device. Furthermore, a program is not necessarily required; a predetermined operation may be performed by configuring a sequential circuit in the maintenance management device 1.

[0048] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be modified as appropriate without departing from the spirit of the present invention. For example, the maintenance management device 1 may be applied not only to an AGV but also to a mobile body that is equipped with casters 10 and can run. [Explanation of symbols]

[0049] 1 Maintenance management device 2 Acquisition part 3 Arithmetic section 4 Storage section 5 Display section 10 Caster 100 Test Equipment 101 Test Stand 102 Running gear 102A Encoder 102L Link Device 102R rotor 103 Loading device 104 Measuring Equipment S Maintenance Management System W Network

Claims

1. a step of conducting a running test of the caster while changing test conditions including the applied load, the type of caster, and the type of floor surface; measuring the amount of wear of the caster and calculating a relational expression between the amount of wear and the running distance based on the obtained measurement value; A step of calculating a future wear amount of the caster provided on the moving body in operation based on the relational expression; and generating a maintenance plan for the mobile body based on the calculated amount of future wear.

2. the relational expression is an approximation expression that expresses, by a straight line, the relationship between the logarithm of the travel distance of the movable body based on the test conditions and the logarithm of the wear amount of the caster, calculating a parameter in the relational expression based on the measured value; The maintenance management method according to claim 1.

3. accumulating test results of the running tests under different test conditions; a step of periodically measuring the operating wear amount of the caster provided on the moving body while it is in operation; and adjusting the parameters based on the test results and the measured values ​​of the operational wear. The maintenance management method according to claim 2.

4. conducting the running test of the caster for which the type information is lacking; and estimating the type of the caster based on the test results. The maintenance management method according to claim 3.

5. and a step of designing a new caster based on the test results and the amount of operational wear. The maintenance management method according to claim 3 or 4.

6. a calculation unit that calculates a relational expression between the amount of wear and a running distance based on measured values ​​of the amount of wear of the casters obtained by running tests of the casters, the test conditions of which include the applied load, the type of caster, and the type of floor surface, calculates future amounts of wear of the casters provided on an operating mobile body based on the relational expression, and generates a maintenance plan for the mobile body based on the calculated future amounts of wear; Maintenance management system.

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