JP5968189B2 - Excavator management apparatus and excavator management method - Google Patents

Description

  The present invention relates to an excavator management apparatus and an excavator management method for calculating the life of a shovel part.

  Stress analysis by the finite element method is widely used to predict the life of excavator parts. In the analysis method disclosed in Patent Document 1, load conditions and boundary conditions used in the finite element method are keyed. The stress range is obtained by performing stress analysis under the load condition and the boundary condition. The obtained stress range is applied to the SN diagram, and the estimated fatigue life is obtained.

JP 2003-149091 A

  When load conditions and boundary conditions for performing stress analysis are different from conditions in an actual operating state, it is difficult to perform life prediction with high accuracy.

According to one aspect of the invention,
An input device that receives detection results from a plurality of sensors that detect the operating state of the excavator;
A processing device that calculates the stress applied to the parts of the excavator by analyzing the detection result of the sensor input through the input device using an analysis model;
The plurality of sensors includes a stress sensor disposed on an upper surface, a bottom surface, and two side surfaces of an attachment connected to the upper swing body of the excavator,
The processing device calculates a time change of stress applied to the attachment from a time change of a detection result of the stress sensor,
There is provided an excavator management device for obtaining a lifetime of the attachment based on a calculation result of a time change of stress.

According to another aspect of the invention,
(A) The detection result of the sensor of the shovel equipped with a plurality of sensors for detecting the operation state, including stress sensors arranged on the upper surface, the bottom surface, and the two side surfaces of the attachment connected to the upper swing body of the shovel. Acquiring time variation;
(B) applying the detection results at a plurality of times acquired from the stress sensor to an analysis using an analysis model, and calculating a stress applied to the attachment, thereby obtaining a time change in stress;
(C) A shovel management method for obtaining the lifetime of the attachment based on the time change of the stress is provided.

  Since the time change of stress is obtained based on the detection result of the sensor attached to the excavator, it is possible to improve the accuracy of component life prediction.

1A and 1B are a side view and a plan view, respectively, of a shovel to be managed by the shovel management apparatus according to the first embodiment. FIG. 2 is a block diagram of the shovel management device according to the first embodiment and a schematic diagram of the shovel to be managed. FIG. 3 is a flowchart of the excavator management method according to the first embodiment. 4A to 4D are schematic diagrams illustrating an example of a series of operations repeated in the excavator. 5A to 5C are graphs showing examples of time waveforms (time changes) of the boom cylinder hydraulic pressure, the arm tip position, and the turning angle during the operation of the shovel, respectively. FIG. 6 is a graph showing the calculation result of the stress distribution in the boom at a certain analysis time in shades. FIG. 7 is a graph showing a time waveform of the stress applied to the evaluation point Ep shown in FIG. FIG. 8 is a graph showing an example of the SN diagram. FIG. 9 is a graph showing the distribution of the cumulative damage degree in the boom in shades. FIG. 10 is a perspective view of an excavator boom to be evaluated by the excavator evaluation method according to the second embodiment. FIG. 11 is a diagram illustrating a method for calculating the lifetime of a part executed by the excavator management device according to the third embodiment. FIG. 12 is a diagram illustrating a method for calculating the lifetime of a part executed by the excavator management device according to the fourth embodiment.

[Example 1]
FIG. 1A shows a side view of a shovel to be managed by the shovel management apparatus according to the first embodiment. An upper turning body 21 is mounted on the lower traveling body 20. A boom 23 is connected to the upper swing body 21, an arm 25 is connected to the boom 23, and a bucket 27 is connected to the arm 25. As the boom cylinder 24 expands and contracts, the posture of the boom 23 changes. As the arm cylinder 26 expands and contracts, the posture of the arm 25 changes. The posture of the bucket 27 changes due to the expansion and contraction of the bucket cylinder 28. The boom cylinder 24, the arm cylinder 26, and the bucket cylinder 28 are hydraulically driven. An attachment is constituted by the boom 23, the arm 25, and the bucket 27.

  As an attachment attitude sensor, a boom angle sensor, an arm angle sensor, and a bucket angle sensor are provided. As an attachment load sensor, a boom pressure sensor that measures the hydraulic pressure (cylinder pressure) in the cylinder of the boom cylinder 24, an arm pressure sensor that measures the cylinder pressure of the arm cylinder 26, and a bucket that measures the cylinder pressure of the bucket cylinder 28. A pressure sensor is provided. Note that a displacement sensor that measures the amount of expansion and contraction of the cylinder can be used as the attachment attitude sensor instead of the angle sensor.

  FIG. 1B is a plan view of an excavator to be managed by the excavator management apparatus according to the first embodiment. The turning motor 34 turns the upper turning body 21 with respect to the lower traveling body 20. As the turning motor 34, an electric motor or a hydraulic motor is used. The turning angle sensor 35 measures the rotation angle of the rotation shaft of the turning motor 34. For the turning angle sensor 35, for example, a resolver is used. Based on the measurement result of the turning angle sensor 35, the turning angle θ of the upper turning body 21 can be calculated. Here, the turning angle θ means an angle at which the upper turning body 21 turns with reference to the posture in which the boom 23 or the like faces the front of the lower traveling body 20. Note that an acceleration sensor may be used instead of the turning angle sensor as a sensor for measuring a physical quantity related to the turning motion of the upper turning body 21.

FIG. 2 shows a block diagram of the excavator management device 40 according to the first embodiment and a schematic diagram of the excavator 50 to be managed. The excavator management device 40 includes an input device 41, a processing device 42, a storage device 43, and an output device 44. The input device 41 receives data transmitted from the shovel 50 that is a management target via the communication network 51.

  The hydraulic pressure in each hydraulic cylinder measured by the load sensor of the attachment, the angle measured by the attitude sensor of the attachment, and the turning angle θ measured by the turning angle sensor 35 (FIG. 1B) are processed via the input device 41. Input to the device 42. Based on the measurement values of the load sensor, the posture sensor, and the turning angle sensor 35, the posture of the attachment and the load applied to the attachment are specified. The output device 44 displays the processing result of the processing device 42. The input device 41 is also used for an operator to input a command to the processing device 42. The input device 41 includes a keyboard, a communication device, and the like. The storage device 43 stores a computer program executed by the processing device 42 and various data used for processing.

  FIG. 3 shows a flowchart of the excavator management method according to the first embodiment. First, in step S1, the processing device 42 obtains measured values for at least one cycle of a series of repeated operations during work by the excavator 50, the attachment attitude sensor, the attachment load sensor, and the turning angle sensor 35 (see FIG. 1B). From the turning angle sensor 35, the turning angle θ (FIG. 1B) of the upper turning body 21 is acquired. The attitude of the shovel is specified by the detected values of the attachment attitude sensor and the turning angle sensor 35. Of the series of operations, an operator may set a range in which measurement values are acquired by the attachment attitude sensor, the attachment load sensor, and the turning angle sensor 35.

  4A to 4D show an example of a series of operations repeated in the excavator 50. FIG. 4A to 4D schematically illustrate the posture of the excavator 50 at any point in each step within one cycle of a series of operations, specifically, excavation start, lifting swivel, soil removal, and return swirl steps. Shown in At the time of driving the shovel, for example, the postures shown in FIGS. 4A to 4D appear in order by repeating a series of operations.

  FIGS. 5A to 5C show examples of time waveforms (time changes) of the hydraulic pressure in the boom cylinder 24 (FIG. 1A), the height of the tip of the arm 25 (FIG. 1A), and the turning angle during the operation of the shovel, respectively. . Solid lines L1 and L2 shown in FIG. 5A indicate the rod-side hydraulic pressure and the bottom-side hydraulic pressure in the boom cylinder 24, respectively. 5A to 5C, time t1 corresponds to the excavation start shown in FIG. 4A. Excavation is performed during a period from time t1 to t2. During the period from time t2 to t3, the boom lifting and turning operations shown in FIG. 4B are performed. During the period from time t3 to t4, the soil removal and return turning operations shown in FIG. 4C are performed. Corresponding to the repetition of a series of operations, a waveform that approximates the waveform from time t1 to t4 appears periodically.

  In step S2 shown in FIG. 3, a plurality of times to be analyzed (hereinafter referred to as “analysis time”) are extracted within one cycle of a series of operations. As an example, as shown in FIG. 5A, four analysis times of times t1 to t4 are extracted from one cycle. For example, characteristic times such as the hydraulic pressure in the cylinder, the peak of the time waveform of the turning angle, and the inflection point are extracted as the analysis time. If the number of analysis times to be extracted is increased, the analysis accuracy is improved, but the calculation time required for the analysis is increased. The processing device 42 (FIG. 2) may automatically extract the analysis time based on the time waveforms shown in FIGS. 5A to 5C, or the operator may determine the analysis time by observing the time waveform. The analysis time may be input from the input device 41.

In step S3 shown in FIG. 3, at each analysis time, the distribution of stress applied to each component such as a boom and an arm is calculated using the analysis model. The stress distribution is calculated based on the specific posture of the excavator determined at each analysis time. That is, the distribution of stress is calculated based on the load applied to the parts of the shovel for each position of the various shovels that appear within one cycle of a series of repeated operations. For the calculation of the stress distribution, for example, a numerical analysis method such as a finite element method can be applied. At this time, the posture applied to the shovel and the load applied to the parts of the shovel are used as boundary conditions. Here, the load is represented by a vector. The magnitude and direction of the load are determined by the hydraulic pressure in the hydraulic cylinder, the axial direction of the hydraulic cylinder (attachment posture), and the turning angular acceleration. The turning angular acceleration is calculated by differentiating the turning angle θ (FIG. 1B) twice.

  FIG. 6 shows the calculation result of the stress distribution of a part in the boom 23 at a certain analysis time. The stress is calculated for each node constituting each element of the analysis model. In FIG. 6, locations where the stress is relatively large are shown in a relatively dark color. The analysis result of the stress distribution as shown in FIG. 6 is calculated for each analysis time and for each part.

  In FIG. 7, the time waveform of the stress added to the evaluation location Ep (FIG. 6) of the parts of the excavator is shown. The stress is calculated at each of the analysis times t1 to t4. The time waveform of the stress shown in FIG. 7 is obtained for a plurality of evaluation points (a plurality of nodes when the finite element method is used) for each component such as the boom 23, the arm 25, and the bucket 27.

  In step S4 shown in FIG. 3, the cumulative damage degree is calculated for each evaluation point of each part. Thereby, the distribution of the cumulative damage degree in the part is obtained. The cumulative damage degree is calculated based on the extreme value of the stress extracted from the time change of the stress. Here, the “accumulated damage degree” is obtained by accumulating damage received during a series of repeated operations over a period of one cycle. Hereinafter, an example of a method for calculating the cumulative damage degree will be described. First, the maximum value and the minimum value of the time waveform of stress shown in FIG. 7 are detected. Based on the maximum value and the minimum value, a stress range Δσ that is a range in which the stress fluctuates is obtained, and an appearance frequency for each stress range Δσ is obtained. The appearance frequency of the stress range Δσi is represented by ni.

FIG. 8 shows an example of the SN diagram. For example, in the SN diagram shown in FIG. 8, the fatigue life (number of repetitions of fracture) in the stress range Δσi is Ni. The cumulative damage degree D is expressed by the following formula according to the cumulative fatigue damage law (also known as the linear damage law).

  FIG. 9 shows an example of the distribution of the cumulative damage degree D in a part of the boom 23. In FIG. 9, a region where the cumulative damage degree D is relatively large is indicated by a relatively dark color. Fatigue failure occurs when the cumulative damage degree D becomes 1 or more. The fatigue life can be obtained from the cumulative damage degree D and the operation status (time corresponding to the sampled period).

  In step S5 shown in FIG. 3, the lifetime of the component is calculated. The fatigue life of the evaluation portion where the cumulative damage degree D obtained in step S4 is the maximum is the life of the component. In step S6, the evaluation result is output. For example, the processing device 42 (FIG. 2) displays the distribution of the cumulative damage degree D shown in FIG. 9 and the life of the parts on the output device 44 (FIG. 2).

  In step S7 shown in FIG. 3, it is determined whether or not the evaluation result satisfies the reference condition. As an example, when a short life is calculated with respect to a predetermined life, it is determined that the load is large, and a warning is issued in step S8. If the evaluation result satisfies the standard condition, the process is terminated.

Based on the distribution of the cumulative damage degree D, the maintenance inspector can extract a portion that should be inspected particularly at the next inspection. When a warning is issued, preparation for parts replacement can be started. The excavator designer can extract a portion where the mechanical strength should be increased based on the distribution of the cumulative damage degree D.

  In the first embodiment, stress analysis using a numerical analysis model is performed based on the posture of the attachment collected during the actual operation of the excavator, the load applied to the attachment, and the turning angle, and the predicted life is calculated. For this reason, the prediction precision of a lifetime can be improved. Furthermore, the excavator owner and the operator can grasp and learn an operation method for reducing damage to the excavator parts. As a result, the life of the shovel can be extended. For the shovel designer, the load status and operating status can be obtained.

  The difference between the calculated cumulative damage value (the value for one cycle) over the entire cycle that has been operated up to the present time and 1 that indicates fatigue failure is the remaining time from the current time until fatigue failure occurs. This corresponds to the cumulative damage level. Using this fact, the remaining life can be obtained from the remaining cumulative damage degree and the operation time up to the present time. When the obtained remaining life falls below a predetermined reference value, the remaining life is displayed on the output device 44 (FIG. 2), and a display prompting maintenance of a portion where fatigue failure may occur may be performed. Is possible.

[Example 2]
Next, an excavator management method according to the second embodiment will be described with reference to FIG. Hereinafter, differences from the first embodiment will be described, and description of the same configuration will be omitted. In Example 1, in step S2 shown in FIG. 3, the analysis time was extracted based on the time waveform of the detected values of the posture sensor and the load sensor. In the second embodiment, the analysis time is extracted based on the result of measuring the stress.

  FIG. 10 is a perspective view of the shovel boom 23. A plurality of stress sensors 37 are attached to the boom 23. For example, a strain gauge can be used as the stress sensor 37. The boom 23 is mainly composed of an upper surface, a bottom surface, and side surfaces. The stress sensor 37 is attached to, for example, the upper surface, the bottom surface, and the two side surfaces in the vicinity of the intermediate point between the base portion and the central portion of the boom 23 and in the vicinity of the intermediate point between the distal end and the central portion.

  In the second embodiment, in step S <b> 1 illustrated in FIG. 3, in addition to the physical quantity indicating the attachment posture and the like, a strain detection value by the stress sensor 37 is acquired. Thereby, instead of obtaining the stress by converting the detection value of the pressure sensor, the stress is directly detected by the stress sensor 37, and the analysis time is determined from the detected stress. Further, a stress distribution as shown in FIG. 6 is calculated for each of a plurality of preset load conditions, and a plurality of calculation results of the stress distribution are prepared as a stress distribution reference table. The detected value of the stress by the stress sensor is compared with the calculated value of the stress at the node corresponding to the stress sensor mounting position in the plurality of stress distributions stored in the stress distribution reference table. A stress distribution in which both are approximated is selected from a plurality of stress distributions stored in the stress distribution reference table. For each determined analysis time, an approximate stress distribution is selected from the stress distribution reference table, and the fatigue life can be obtained.

  Hereinafter, the analysis time determination method will be described in more detail. The strain is detected by the stress sensor 37 during a series of operations of the shovel. Based on the detected strain, a time waveform of stress for one cycle of a series of operations is obtained. Paying attention to the maximum value and the minimum value of the stress time waveform, the analysis time is extracted from a plurality of times when the stress shows the maximum value and the minimum value.

When a plurality of postures to be analyzed are determined using one evaluation target shovel, it is not necessary to attach a stress sensor to the evaluation target shovel when evaluating another shovel. Moreover, in order to extract the analysis times t1 to t4, the stress sensor may be removed after the analysis time is determined for the excavator in which the stress sensor is attached and the data is collected.

  In the first embodiment and the second embodiment, data communication is performed between the excavator 50 and the excavator management device 40 (FIG. 2) via the communication network 51. However, the excavator management device 40 is mounted on the excavator 50. Also good. In this case, the measurement values measured by the attachment attitude sensor, load sensor, and turning angle sensor 35 attached to the excavator are input to the processing device 42 via the input device 41 without passing through the communication network 51. The

  Stress is a parameter directly related to fatigue life prediction. In the second embodiment, as described above, when the fatigue life is predicted, the stress distribution is obtained using the detected value of the stress directly measured by the stress sensor. For this reason, the accuracy of calculation of the stress distribution can be increased. As a result, the fatigue life prediction accuracy can be increased.

[Example 3]
With reference to FIG. 11, a method for calculating the lifetime of a part executed by the shovel management apparatus according to the third embodiment will be described. Hereinafter, differences from the first embodiment will be described, and description of the same configuration will be omitted.

  In the storage device 43 (FIG. 2), excavator typical postures A1, A2, A3,..., Standard loads B1, B2, B3,..., And standard stresses C1, C2, C3 are stored. ,... Are stored in advance. The representative postures include postures at the analysis time such as excavation start, lifting swivel, earth removal, and return swirl shown in FIGS. 4A to 4D, for example. The posture at the start of excavation, which is one analysis time, includes a plurality of postures depending on the distance from the base to the excavation site, the depth of the excavation site, and the like. Similarly, a plurality of postures are also included in the representative postures at the time of lifting, earth removal, and return turning.

  As a standard load corresponding to each representative posture, a load measured by one load sensor among a plurality of load sensors is employed. As the value of the standard load, for example, the most common load that is generated when the excavator takes a representative posture during excavation work is adopted. The standard stress corresponding to each of the representative postures means the stress applied to the component when the shovel takes the representative posture and a standard load is applied to the attachment. The standard stress is defined at a plurality of evaluation points Ep (FIG. 6). The standard stress value is calculated in advance using, for example, an analysis method such as the finite element method described in the first embodiment.

  Similar to step S1 shown in FIG. 3 of the first embodiment, the posture sensor and the load sensor obtain measurement values for at least one cycle of a series of repeated operations. At the analysis time, the posture acquired by the posture sensor and the representative posture stored in the correspondence table 45 are compared, and the most representative representative posture is extracted. As an example, the posture A2 is extracted.

  In the first embodiment, the stress distribution is calculated using the analysis model in step S3 of FIG. 3, but in the third embodiment, the stress is calculated from the correspondence table 45 stored in the storage device 43 without using the analysis model. Ask for. Hereinafter, a method for obtaining the stress will be described with reference to FIG.

  The actual measurement value of the load sensor is compared with the standard load B2 corresponding to the representative posture A2 in the correspondence table 45. Based on the comparison result, a stress conversion coefficient is obtained. The conversion coefficient is calculated by dividing the actual measurement value of the load sensor by the standard load B2.

The stress is obtained by multiplying the standard stress C2 corresponding to the representative posture A2 by the conversion coefficient. The stress can be obtained by a similar procedure at a plurality of analysis times. Thereby, the time waveform of the stress as shown in FIG. 7 is obtained. The procedure after the time waveform of the stress is obtained is the same as the procedure after step S4 of the first embodiment shown in FIG.

  In the third embodiment, it is not necessary to perform calculations such as the finite element method when calculating the stress applied to the parts of the excavator. For this reason, the load added to the processing apparatus 42 (FIG. 2) can be reduced.

[Example 4]
With reference to FIG. 12, a method for calculating the lifetime of a part executed by the excavator management device according to the fourth embodiment will be described. Hereinafter, differences from the first embodiment will be described, and description of the same configuration will be omitted.

  In the fourth embodiment, the storage device 43 (FIG. 2) stores a map 46 that associates the stress generated in the component with the combination of the shovel posture and the load applied to the component. In the map 46, stress R for various postures P1, P2, P3,... Appearing in a series of operations of the excavator and various loads Q1, Q2, Q3,. Are associated. For example, the stress Rij is associated with the combination of the posture Pi and the load Qj. Here, i and j are positive integers.

  Similar to step S1 shown in FIG. 3 of the first embodiment, the posture sensor and the load sensor obtain measurement values for at least one cycle of a series of repeated operations. At the analysis time, the stress is obtained from the map 46 based on the posture acquired by the posture sensor and the load acquired by the load sensor. For example, stresses R32, R43, R34, and R24 are extracted corresponding to the analysis times t1, t2, t3, and t4. Thereby, the time waveform of the stress as shown in FIG. 7 is obtained. The procedure after the time waveform of the stress is obtained is the same as the procedure after step S4 of the first embodiment shown in FIG.

  In the fourth embodiment, similarly to the third embodiment, it is not necessary to perform an operation such as a finite element method when calculating the stress applied to the parts of the excavator. For this reason, the load added to the processing apparatus 42 (FIG. 2) can be reduced.

  In the first embodiment, the stress is calculated using the analysis model. In the third embodiment, the stress is calculated using the correspondence table 45 (FIG. 11). In the fourth embodiment, the stress is calculated using the map 46 (FIG. 12). Stress was calculated. You may correct | amend the stress calculated | required by these methods using the measured value of the stress sensor directly attached to the shovel as shown in Example 2. FIG. Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made. Moreover, in Examples 1-4, although the cumulative damage degree was calculated based on the stress change for 1 period repeated with an excavator, only the arbitrary process in 1 period was extracted, and the stress change in the extracted process Based on the above, the cumulative damage degree and the remaining life may be calculated.

20 Lower traveling body 21 Upper revolving body 23 Boom 24 Boom cylinder 25 Arm 26 Arm cylinder 27 Bucket 28 Bucket cylinder 34 Turning motor 35 Turning angle sensor 37 Stress sensor 40 Excavator management device 41 Input device 42 Processing device 43 Storage device 44 Output device 45 Correspondence table 46 Map 50 Excavator 51 Communication network

Claims (11)

An input device that receives detection results from a plurality of sensors that detect the operating state of the excavator;
A processing device that calculates the stress applied to the parts of the excavator by analyzing the detection result of the sensor input through the input device using an analysis model;
The plurality of sensors includes a stress sensor disposed on an upper surface, a bottom surface, and two side surfaces of an attachment connected to the upper swing body of the excavator,
The processing device calculates a time change of stress applied to the attachment from a time change of a detection result of the stress sensor,
An excavator management device for obtaining a lifetime of the attachment based on a calculation result of a time change of stress. An input device that receives detection results from a plurality of sensors that detect the operating state of the excavator;
A processing device for calculating the stress applied to the parts of the excavator by analyzing the detection result of the sensor input through the input device using an analysis model;
Have
The plurality of sensors includes a stress sensor disposed on an upper surface, a bottom surface, and two side surfaces of an attachment connected to the upper swing body of the excavator,
The processing device calculates a time change of stress applied to the attachment from a time change of detection results of the plurality of sensors,
Based on the calculation result of the time change of stress, obtain the life of the attachment,
The plurality of sensors further includes a sensor that measures a load applied to the excavator component and a posture of the excavator, and the processing device includes a load corresponding to the posture of the shovel that appears in a series of repeated operations, and the detection result of said stress sensor, calculated to Cie Yoberu management device the time change of stress applied to the attachment.   The shovel management device according to claim 2, wherein the processing device obtains the life of the attachment based on an extreme value of stress extracted from a time change of the stress for one cycle of the series of operations.   The excavator management device according to claim 2, wherein the processing device obtains a portion having the shortest life from a stress distribution in the attachment.   The processing apparatus performs an analysis using the analysis model at a plurality of time points determined based on a time change of stress applied to the attachment measured by the stress sensor during a period in which the excavator performs the series of operations. The shovel management device according to any one of claims 2 to 4. In addition, including an output device,
The processing apparatus obtains and obtains a distribution in the attachment of a cumulative damage degree obtained by accumulating damage received during the series of operations over a period of one cycle based on a calculation result of a time change of stress applied to the attachment. The excavator management device according to any one of claims 2 to 5, wherein a distribution of the cumulative damage degree thus obtained is output to the output device. (A) The detection result of the sensor of the shovel equipped with a plurality of sensors for detecting the operation state, including stress sensors arranged on the upper surface, the bottom surface, and the two side surfaces of the attachment connected to the upper swing body of the shovel. Acquiring time variation;
(B) applying the detection results at a plurality of times acquired from the stress sensor to an analysis using an analysis model, and calculating a stress applied to the attachment, thereby obtaining a time change in stress;
(C) A shovel management method for obtaining a lifetime of the attachment based on a time change of the stress. (A) The detection result of the sensor of the shovel equipped with a plurality of sensors for detecting the operation state, including stress sensors arranged on the upper surface, the bottom surface, and the two side surfaces of the attachment connected to the upper swing body of the shovel. Acquiring time variation;
(B) analyzing the detection results of a plurality of times acquired from the sensor using an analysis model, and calculating a stress applied to the attachment, thereby obtaining a time change of stress;
(C) obtaining a lifetime of the attachment based on a time change of the stress ;
Have
The plurality of sensors further measure a load applied to the attachment and an attitude of the shovel,
In the step (a), obtaining a load corresponding to the posture of the shovel that appears in a series of repeated operations,
Wherein In the step (b), the posture of the shovel, the load corresponding to the position, and on the basis of the detection result of said stress sensor, shovel management method asking you to time variation of the stress. The shovel management method according to claim 8, wherein in the step (c), the lifetime of the attachment is obtained based on an extreme value of stress extracted from a time change of the stress for one cycle of the series of operations. The excavator management method according to claim 8 or 9, wherein, in the step (c), an evaluation point having the shortest lifetime is obtained from a plurality of evaluation points of the attachment. Furthermore, before the step (a),
(D) obtaining a time change of stress actually measured by the stress sensor during a period in which the excavator performs the series of operations;
(E) determining a plurality of evaluation times to be analyzed based on the time change of the stress,
The excavator management method according to any one of claims 8 to 10, wherein in the step (a), the analysis using the analysis model is performed at the evaluation time determined in the step (e).