State monitoring device and storage medium

Abstract

A state monitoring device is provided with a first acquisition unit (201), a second acquisition unit (202), and an estimation unit (203). The first acquisition unit is provided in a joint portion of a rotatable arm, and acquires a first physical quantity related to a mechanical element provided in the joint portion. The second acquisition unit is provided on a distal end side of the arm, which is different from a base end side on which the joint portion is disposed, and acquires a second physical quantity pertaining to the motion state of the arm. The estimation unit estimates the state of the machine element on the basis of the first physical quantity acquired by the first acquisition unit and the second physical quantity acquired by the second acquisition unit.

Description

Technical Field

[0001] The present invention relates to a state monitoring device and a storage medium.

[0002] This application claims the priority of Japanese Patent Application No. 2022-201123 filed in Japan on December 16, 2022, and incorporates its content herein. Background Art

[0003] Conventionally, a speed reducer has been mounted on a joint portion of an arm of construction machinery. If the deterioration of the speed reducer progresses, the vibration becomes larger than in the normal state. Therefore, for example, the following process is performed: an acceleration sensor is used to determine an abnormality (failure, deterioration) of gears such as a speed reducer. The vibration of the gears is small both during deterioration and in the normal state without deterioration. Therefore, among the vibrations of various frequencies detected by the acceleration sensor, it is necessary to pay attention to the target frequency (target frequency) suitable for estimating the failure of the gears, and determine the abnormality based on the magnitude of the vibration of the target frequency.

[0004] For example, the target frequency is determined based on the number of teeth and the rotational speed of the gear. For example, the rotational speed of the gear can be obtained from the mother machine. As a related technique, the following method is disclosed (for example, refer to Patent Document 1): using an expression obtained by approximating the relationship between the normal rotational speed of a rotating device and the vibration value of the rotating device, the vibration value at an arbitrary rotational speed is corrected to the vibration value at the reference rotational speed, and an abnormality is determined based on the case where the corrected value exceeds a threshold value.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Laid-Open No. 7-218333 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] However, in the method of obtaining the target frequency from the mother machine, wiring of a signal line from the mother machine to the outside of the mother machine is required, which causes trouble. Therefore, it is impossible to obtain the target frequency with a simple structure. Therefore, in the prior art, there is a problem that it is impossible to estimate the abnormality of gears with a simple structure.

[0010] An object of the present invention is to provide a state monitoring device and a storage medium capable of estimating the state of mechanical elements (for example, the state of gears) with a simple structure.

[0011] Means for Solving the Problems

[0012] One aspect of the state monitoring device of the present invention includes: a first detection unit that detects a first physical quantity related to a mechanical element of a joint portion of an arm that can rotate; a second detection unit that is provided on the front end side of the arm different from the base end side where the joint portion is disposed, and detects a second physical quantity related to the motion state of the arm; and an estimation unit that estimates the state of the mechanical element based on the first physical quantity detected by the first detection unit and the second physical quantity detected by the second detection unit.

[0013] According to the above structure, even without obtaining information from the mother machine, the state of the mechanical element can be estimated with a simple structure.

[0014] In the above structure, it may also be that the mechanical element is a gear provided in the joint portion, the first physical quantity is the vibration of the gear, and the second physical quantity is at least one of the acceleration and angular velocity of the arm. The estimation unit may also have a calculation unit that calculates a specific frequency of the vibration based on the detection result of the second physical quantity during a specified period when the arm is moving and the number of teeth of the gear. The estimation unit may further use the calculated specific frequency and the detection result of the first physical quantity during the specified period to estimate the state of the gear.

[0015] According to the above structure, the state of the gear (such as an abnormality of the gear) can be estimated with a simple structure.

[0016] In the above structure, it may also be that the estimation unit extracts data corresponding to the calculated specific frequency from the time series data of the detection result of the first physical quantity, and estimates the state of the gear based on the extracted data.

[0017] According to the above structure, large-scale operations such as FFT (Fast Fourier Transformation) are not required, and power consumption can be reduced. Therefore, the state monitoring device can be applied to a simple device (such as a smart sensor) driven by a battery.

[0018] In the above structure, it may also be that the estimation unit performs a filtering process for extracting data corresponding to the specific frequency from the time series data of the detection result of the first physical quantity, and estimates the state of the gear based on the comparison result between the extracted data and a specified threshold.

[0019] According to the above structure, the state of the gear, such as whether there is an abnormality in the gear, can be estimated with a simpler structure.

[0020] In the above structure, the second physical quantity may also be the three-axis acceleration of the arm. The estimation unit may also have a determination unit that determines whether it is in a constant-speed state indicating that the arm is operating at a constant speed based on the comparison result between the combined value of each axis of the three-axis acceleration and the gravitational acceleration. The estimation unit may also estimate the state of the mechanical element based on the detection result of the first detection unit at the time point determined to be in the constant-speed state.

[0021] According to the above structure, the accuracy of estimating (such as anomaly estimation) the state of the mechanical element can be improved.

[0022] In the above structure, it may also be that when the combined value of each axis within a specified period is consistent with the gravitational acceleration and the values of each axis within the specified period are indeterminate, the determination unit determines that the arm is in the constant-speed state.

[0023] According to the above structure, the constant-speed state of the arm can be simply determined.

[0024] In the above structure, the determination unit may also determine a non-constant-speed state other than the constant-speed state based on the combined value of each axis and the gravitational acceleration. The estimation unit may not estimate the state of the mechanical element in the non-constant-speed state.

[0025] According to the above structure, the accuracy of estimating (such as anomaly estimation) the state of the mechanical element can be improved.

[0026] In the above structure, it may also be that when the combined value of each axis is inconsistent with the gravitational acceleration, the determination unit determines an acceleration / deceleration state indicating that the arm is operating in an accelerating or decelerating manner as the non-constant-speed state.

[0027] According to the above structure, the acceleration / deceleration state of the arm can be simply determined.

[0028] In the above structure, it may also be that the mechanical element is a gear provided at the joint portion, the first physical quantity is the vibration of the gear, and the second physical quantity includes the rotational speed of the arm and the three-axis acceleration of the arm. The estimation unit may also have: a determination unit that determines whether it is in a constant-speed state indicating that the arm is operating at a constant speed based on the comparison result between the combined value of each axis of the three-axis acceleration and the gravitational acceleration; and a calculation unit that calculates a specific frequency of the vibration based on information including at least the rotational speed of the arm and the number of teeth of the gear at the time point determined to be in the constant-speed state. The estimation unit may also extract data corresponding to the calculated specific frequency from the time-series data of the detection result of the first physical quantity and estimate the state of the gear based on the extracted data.

[0029] According to the above structure, the isochronous state of the arm can be simply determined, large-scale operations such as FFT are not required, and power consumption can be reduced. Therefore, the state monitoring device can be applied to a simple device (such as a smart sensor) driven by a battery.

[0030] One aspect of the storage medium of the present invention is a computer-readable storage medium storing a program that causes a computer to function as a state monitoring device. The storage medium stores the program that causes the computer to function as a first acquisition unit, a second acquisition unit, and an estimation unit. The first acquisition unit acquires the first physical quantity from a first detection unit that is provided at a joint portion of a rotatable arm and detects a first physical quantity related to a mechanical element provided at the joint portion. The second acquisition unit acquires the second physical quantity from a second detection unit that is provided at a front end side of the arm different from the base end side where the joint portion is disposed and detects a second physical quantity related to a motion state of the arm. The estimation unit estimates the state of the mechanical element based on the first physical quantity acquired by the first acquisition unit and the second physical quantity acquired by the second acquisition unit.

[0031] According to the above structure, even without obtaining information from the mother machine, the state of the gear (such as an abnormality of the gear) can be estimated with a simple structure.

[0032] Effects of the Invention

[0033] According to the present invention, the state of the gear (such as an abnormality of the gear) can be estimated with a simple structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is an explanatory view of a construction machine 1 according to an embodiment.

[0035] Figure 2 It is a block diagram showing an example of the functional structure of the state monitoring device 100.

[0036] Figure 3 It is a schematic view showing an outline of the state monitoring device 100.

[0037] Figure 4 It is an explanatory view of the hardware structure of the state monitoring device 100.

[0038] Figure 5 It is a flowchart showing an example of the processing performed by the estimation control unit 200.

[0039] Figure 6 It is a timing chart related to the abnormality estimation performed by the estimation control unit 200 and the change amount sensor 24. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] An embodiment of the present invention will be described with reference to the accompanying drawings.

[0041] (Construction machine 1)

[0042] Figure 1 is an explanatory view of the construction machine 1 according to the embodiment. As Figure 1 shown, the construction machine 1 is, for example, a so-called power excavator which is a kind of excavator. The construction machine 1 includes a main body 2, an arm portion 4 (an example of an arm), and a rotating shaft portion 20 (an example of a joint portion). The main body 2 has a slewing portion 3a and a traveling portion 3b.

[0043] (Arm portion 4)

[0044] The arm portion 4 includes a boom 5, an arm 7, and a bucket 9. The boom 5 is connected to the main body 2 and can rotate relative to the main body 2. The arm 7 is connected to the boom 5 and can rotate relative to the boom 5. The bucket 9 is connected to the arm 7 and can rotate relative to the arm 7.

[0045] (Rotating shaft portion 20)

[0046] The rotating shaft portion 20 includes a first rotating shaft portion 20a, a second rotating shaft portion 20b, a third rotating shaft portion 20c, and a fourth rotating shaft portion 20d.

[0047] The first rotating shaft portion 20a rotatably connects the traveling portion 3b and the slewing portion 3a. The second rotating shaft portion 20b rotatably connects the slewing portion 3a (a support portion 3c provided on the slewing portion 3a) and the boom 5. The third rotating shaft portion 20c rotatably connects the boom 5 and the arm 7. The fourth rotating shaft portion 20d rotatably connects the arm 7 and the bucket 9.

[0048] The second rotating shaft portion 20b is provided at a portion of the support portion 3c that is connected to the boom 5 (or a portion of the boom 5 that is connected to the support portion 3c). The third rotating shaft portion 20c is provided at a portion of the boom 5 that is connected to the arm 7 (or a portion of the arm 7 that is connected to the boom 5). The fourth rotating shaft portion 20d is provided at a portion of the arm 7 that is connected to the bucket 9 (or a portion of the bucket 9 that is connected to the arm 7).

[0049] The rotation axis of the first rotating shaft portion 20a is perpendicular to the surface (e.g., the ground) that the traveling portion 3b contacts. The rotation axes of the second rotating shaft portion 20b, the third rotating shaft portion 20c, and the fourth rotating shaft portion 20d are each parallel to the surface that the traveling portion 3b contacts.

[0050] A rotating motor (not shown) and a speed reducer 22 are provided in each of the rotating shaft portions 20.

[0051] Specifically, a first rotation motor (not shown) and a first speed reducer 22a are provided on the first rotation shaft portion 20a. A second rotation motor (not shown) and a second speed reducer 22b are provided on the second rotation shaft portion 20b. A third rotation motor (not shown) and a third speed reducer 22c are provided on the third rotation shaft portion 20c. A fourth rotation motor (not shown) and a fourth speed reducer 22d are provided on the fourth rotation shaft portion 20d. The rotation motor rotates by electricity (power).

[0052] (Reducer 22)

[0053] The speed reducer 22 is a gear mechanism having a plurality of gears that mesh with each other.

[0054] The first speed reducer 22a rotationally drives the slewing unit 3a by the power generated from the first rotation motor. Specifically, the input portion of the first speed reducer 22a is connected to the output portion of the first rotation motor. The output portion of the first speed reducer 22a is connected to the slewing unit 3a. The first speed reducer 22a reduces the rotational speed of the power input from the first rotation motor to the input portion, and outputs the decelerated power from the output portion.

[0055] The second speed reducer 22b rotationally drives the boom 5 by the power generated from the second rotation motor. Specifically, the input portion of the second speed reducer 22b is connected to the output portion of the second rotation motor. The output portion of the second speed reducer 22b is connected to the boom 5. The second speed reducer 22b reduces the rotational speed of the power input from the second rotation motor to the input portion, and outputs the decelerated power from the output portion.

[0056] The third speed reducer 22c rotationally drives the arm 7 by the power generated from the third rotation motor. Specifically, the input portion of the third speed reducer 22c is connected to the output portion of the third rotation motor. The output portion of the third speed reducer 22c is connected to the arm 7. The third speed reducer 22c reduces the rotational speed of the power input from the third rotation motor to the input portion, and outputs the decelerated power from the output portion.

[0057] The fourth speed reducer 22d rotationally drives the bucket 9 by the power generated from the fourth rotation motor. Specifically, the input portion of the fourth speed reducer 22d is connected to the output portion of the fourth rotation motor. The output portion of the fourth speed reducer 22d is connected to the bucket 9. The fourth speed reducer 22d reduces the rotational speed of the power input from the fourth rotation motor to the input portion, and outputs the decelerated power from the output portion.

[0058] (Condition monitoring device 100)

[0059] A state monitoring device 100 (100b to 100d) for estimating an abnormality of a reduction gear 22 is provided in a construction machine 1. The state monitoring device 100 (100b to 100d) estimates the state of mechanical elements constituting the reduction gear 22. Specifically, the state monitoring device 100 (100b to 100d) estimates the state (abnormal state) of the gears constituting the reduction gear 22.

[0060] The abnormalities estimated by the state monitoring device 100 include various objects such as failures, deterioration, the possibility of failure, the degree of deterioration, and the remaining available service life. In addition, by associating thresholds (described later) with various objects respectively, various objects can be discriminated respectively.

[0061] The state monitoring device 100 (100b to 100d) is provided on a rotating shaft portion 20 (20b to 20d).

[0062] As Figure 1 and Figure 2 shown, the state monitoring device 100 includes an acceleration sensor 23 (23b to 23d) and a change amount sensor 24 (24b to 24d). The state monitoring device 100 is, for example, an intelligent sensor and has an acceleration sensor 23 built therein. The acceleration sensor 23 is an example of a first detection unit. The acceleration sensor 23 detects a first physical quantity related to the wear of the gears constituting the reduction gear 22. The first physical quantity is, for example, three-axis acceleration. In addition, the acceleration sensor 23 is a sensor that can detect three-axis angular velocity in addition to three-axis acceleration.

[0063] The change amount sensor 24 is an example of a second detection unit. The change amount sensor 24 (24b to 24d) is provided on an arm portion 4 (boom 5, arm 7, bucket 9).

[0064] The change amount sensor 24 detects a second physical quantity related to the motion state of the arm portion 4. The second physical quantity is, for example, the angular velocity of the arm portion 4. In the present embodiment, the change amount sensor 24 is configured to be able to detect three-axis acceleration and three-axis angular velocity. In addition, for the acceleration sensor 23 and the change amount sensor 24, an intelligent sensor in which each sensor is integrated can also be used.

[0065] (Second state monitoring device 100b)

[0066] A second state monitoring device 100b for estimating an abnormality of a second reduction gear 22b is provided on a second rotating shaft portion 20b. The second state monitoring device 100b includes a second acceleration sensor 23b. The second acceleration sensor 23b detects the vibration of the gears provided in the second reduction gear 22b. In addition, the second state monitoring device 100b may be provided on the housing of the second reduction gear 22b (the housing that houses a plurality of gears of the second reduction gear 22b).

[0067] A second change amount sensor 24b is provided on the boom 5. The second change amount sensor 24b is provided on the front end side of the boom 5 different from the base end side where the second rotation shaft portion 20b is disposed. Specifically, the second change amount sensor 24b is provided on a portion of the boom 5 located on the base end side of the third rotation shaft portion 20c disposed at the front end. The second change amount sensor 24b detects the angular velocity of the boom 5.

[0068] (Third state monitoring device 100c)

[0069] A third state monitoring device 100c for determining a failure (deterioration condition) of the third speed reducer 22c is provided on the third rotation shaft portion 20c. The third state monitoring device 100c includes a third acceleration sensor 23c. The third acceleration sensor 23c detects the vibration of the gears provided in the third speed reducer 22c. In addition, the third state monitoring device 100c may also be provided on the housing of the third speed reducer 22c (the housing that houses a plurality of gears of the third speed reducer 22c).

[0070] A third change amount sensor 24c is provided on the arm 7. The third change amount sensor 24c is provided on the front end side of the arm 7 different from the base end side where the third rotation shaft portion 20c is disposed. Specifically, the third change amount sensor 24c is provided on a portion of the arm 7 located on the base end side of the fourth rotation shaft portion 20d disposed at the front end. The third change amount sensor 24c detects the angular velocity of the arm 7.

[0071] (Fourth state monitoring device 100d)

[0072] A fourth state monitoring device 100d for determining a failure (deterioration condition) of the fourth speed reducer 22d is provided on the fourth rotation shaft portion 20d. The fourth state monitoring device 100d includes a fourth acceleration sensor 23d. The fourth acceleration sensor 23d detects the vibration of the gears provided in the fourth speed reducer 22d. In addition, the fourth state monitoring device 100d may also be provided on the housing of the fourth speed reducer 22d (the housing that houses a plurality of gears of the fourth speed reducer 22d).

[0073] A fourth change amount sensor 24d is provided on the bucket 9. The fourth change amount sensor 24d is provided on a portion of the bucket 9 located on the front end side of the base end side where the fourth rotation shaft portion 20d is disposed. The fourth change amount sensor 24d detects the angular velocity of the bucket 9.

[0074] (Functional structure of the state monitoring device 100)

[0075] Figure 2 It is a block diagram showing an example of the functional structure of the state monitoring device 100.

[0076] Figure 3 is a schematic diagram showing the outline of the state monitoring device 100. Below, with reference to Figure 3 to Figure 2 the estimation control unit 200 shown will be described.

[0077] As Figure 2 shown, the state monitoring device 100 includes an estimation control unit 200, an acceleration sensor 23, and a change amount sensor 24. The estimation control unit 200 includes a first acquisition unit 201, a second acquisition unit 202, an estimation unit 203, a notification unit 204, and a storage unit 210.

[0078] The first acquisition unit 201 acquires vibration data (vibration values) of the gear provided in the speed reducer 22 from the acceleration sensor 23. Thus, the acceleration sensor 23 and the first acquisition unit 201 cooperate with each other to acquire the vibration data of the gear. Therefore, the first acquisition unit 201 functions as a first detection unit together with the acceleration sensor 23. In addition, the vibration data is time series data of the vibration detected by the acceleration sensor 23.

[0079] The second acquisition unit 202 acquires the rotational speed of the arm 4 calculated by the change amount sensor 24. In addition, the change amount sensor 24 and the second acquisition unit 202 cooperate with each other to acquire the rotational speed of the arm 4. Therefore, the second acquisition unit 202 functions as a second detection unit together with the change amount sensor 24.

[0080] Here, the calculation of the rotational speed of the arm 4 will be described. When using the distance L between the acceleration sensor 23 and the change amount sensor 24 and the angular velocity V, the rotational speed N is represented by the following formula 1. In addition, the distance L is pre-stored in the change amount sensor 24.

[0081] N = (V / 2πL) × 60…(1)

[0082] When the change amount sensor 24 detects the angular velocity of the arm 4, it calculates the rotational speed of the arm 4 based on the detected angular velocity and formula 1. In addition, for example, the second acquisition unit 202 may also calculate the rotational speed of the arm 4.

[0083] The estimation unit 203 estimates whether there is an abnormality related to the wear of the gear in the speed reducer 22 based on the vibration data acquired by the first acquisition unit 201 and the rotational speed acquired by the second acquisition unit 202. Below, sometimes estimating whether there is an abnormality related to the wear of the gear in the speed reducer 22 is referred to as "abnormality estimation".

[0084] The storage unit 210 stores various information. The information stored in the storage unit 210 includes, for example, the number of teeth of the speed reducer 22 (the number of teeth of multiple gears), and a threshold value for comparing with the magnitude (amplitude) of the vibration at the target frequency. These information are referred to in the abnormality estimation by the estimation unit 203. In addition, the storage unit 210 may store the estimation result of the abnormality estimation together with the time when the estimation is performed.

[0085] (Regarding abnormality estimation)

[0086] Hereinafter, a specific example of the abnormality estimation will be described.

[0087] The estimation unit 203 includes a calculation unit 203a. The calculation unit 203a calculates a specific frequency (target frequency) for abnormality estimation. Specifically, based on the rotational speed of the arm portion 4 acquired by the second acquisition unit 202 and the number of teeth of the gear, the target frequency is calculated. More specifically, the calculation unit 203a calculates the target frequency by multiplying the rotational speed N acquired by the second acquisition unit 202 by the number of teeth T stored in the storage unit 210. That is, the target frequency F is represented by the following formula 2.

[0088] F = N × T…(2)

[0089] Then, the estimation unit 203 extracts the data corresponding to the target frequency from the time series data of the vibration acquired by the first acquisition unit 201. Specifically, the estimation unit 203 extracts the vibration data of the target frequency from the time series data of the vibration at various frequencies by performing, for example, a filtering process. In the filtering process, for example, a band-pass filter or a low-pass filter is used. These filters can be implemented either by an analog circuit or by software. The estimation unit 203 changes the sampling speed and the interval of the moving average in the filtering process to extract the vibration data of the target frequency.

[0090] Then, the estimation unit 203 performs abnormality estimation based on the extracted data. Specifically, the estimation unit 203 performs abnormality estimation based on the comparison result between the extracted vibration data (vibration data at the target frequency) and the threshold value stored in the storage unit 210. More specifically, the estimation unit 203 compares the amplitude (for example, the root mean square of the amplitude) of the extracted vibration data with the threshold value, and when the comparison result shows that the vibration data is above the threshold value, it is estimated that there is an abnormality related to the wear of the gear.

[0091] In addition, the rotational speed of the arm portion 4 is not limited to being calculated by the change amount sensor 24, and can also be calculated by the calculation unit 203a. In this case, the second acquisition unit 202 only needs to acquire the angular velocity of the arm portion 4 from the change amount sensor 24. The calculation unit 203a can also calculate the rotational speed of the arm portion 4 based on the angular velocity acquired by the second acquisition unit 202 and the above formula 1.

[0092] (Regarding the notification unit 204)

[0093] The estimation unit 203 outputs the estimated result to the notification unit 204. In addition, the estimation unit 203 may be configured to output the estimated result to the notification unit 204 when an abnormality is estimated, and not to output the estimated result to the notification unit 204 when no abnormality is estimated. Additionally, the estimation unit 203 may store the estimated result in the storage unit 210.

[0094] In addition, the estimation unit 203 may be configured to store the estimated result in the storage unit 210 when an abnormality is estimated, and not to store the estimated result in the storage unit 210 when no abnormality is estimated.

[0095] The notification unit 204 causes a prescribed output device to notify the estimated result output from the estimation unit 203. Specifically, when the estimation unit estimates that an abnormality exists, the notification unit 204 causes the prescribed output device to notify this fact. The prescribed output device includes a light-emitting unit such as an LED, a speaker, and an external device. That is, the notification unit 204 notifies the fact of an abnormality through the light emission of an LED or the like, the sound from the speaker, and the external device based on communication.

[0096] In addition, the notification unit 204 may perform this notification by at least one of the methods of light emission, sound, and communication. For example, it may also perform this notification by all methods.

[0097] (Regarding the timing of estimating an abnormality)

[0098] Here, when the arm 4 is in the stopped state, the speed reducer 22 does not vibrate. Therefore, even if an abnormality is estimated, no abnormal estimated result can be obtained. In addition, when the arm 4 is in the acceleration / deceleration state, a quantity corresponding to the acceleration / deceleration is added to the vibration detected by the acceleration sensor 23, resulting in an indefinite target frequency. That is, when the arm 4 is in the stopped state or the acceleration / deceleration state, it is impossible to perform abnormality estimation with high precision.

[0099] Therefore, in the present embodiment, it is set to perform abnormality estimation when the arm 4 is in the constant-speed state. Next, the determination of the constant-speed state of the arm 4 will be described.

[0100] (Regarding the determination of the constant-speed state)

[0101] The change amount sensor 24 detects the acceleration of three axes as the second physical quantity related to the motion state of the arm 4. The second acquisition unit 202 acquires the acceleration of three axes from the change amount sensor 24. The estimation unit 203 includes a determination unit 203b. The determination unit 203b determines whether the arm 4 is in a constant velocity state based on the comparison result between the combined value of each axis of the three-axis acceleration acquired by the second acquisition unit 202 and the gravitational acceleration. In addition, the motion of the arm 4 is low speed (low frequency) compared to the vibration of the speed reducer 22. Therefore, the determination unit 203b extracts, for example, by a low-pass filter, the acceleration related to the motion of the arm 4 and determines whether the arm 4 is in a constant velocity state.

[0102] The determination unit 203b determines the constant velocity state when the combined value of each axis within a specified period is consistent with the gravitational acceleration and the values of each axis within the specified period are indeterminate. The specified period is a preset period, for example, about several seconds.

[0103] Here, if the vibrations of the X-axis, Y-axis, and Z-axis of the acceleration acquired by the second acquisition unit 202 are defined as Ax, Ay, and Az respectively, the acceleration caused by the gravitational acceleration is defined as Gx, Gy, and Gz, and the acceleration caused by the motion of the speed reducer 22 is defined as Rx, Ry, and Rz, the vibration A is expressed by the following equations 3 to 5.

[0104] Ax = Gx + Rx…(3)

[0105] Ay = Gy + Ry…(4)

[0106] Az = Gz + Rz…(5)

[0107] The combined value of Gx, Gy, and Gz is expressed by the following equation 6.

[0108] (Gx 2 + Gy 2 + Gz 2 ) 1 / 2 = 9.8m / s 2 …(6)

[0109] In the case of being in a constant velocity state, since there is no acceleration or deceleration,

[0110] Rx = Ry = Rz = 0

[0111] Therefore, the above equations 3 to 5 are expressed as follows.

[0112] Ax = Gx

[0113] Ay = Gy

[0114] Az = Gz

[0115] Therefore, the combined values of Ax, Ay, and Az are 9.8 m / s 2 .

[0116] In addition, since the arm 4 moves, the directions of the accelerations of the three axes detected by the change amount sensor 24 are not fixed. That is, the respective values of Ax, Ay, and Az (= Gx, Gy, Gz) are not fixed. Therefore, when the conditions of "the combined value of Ax, Ay, and Az = 9.8 m / s 2 " and "the respective values of Ax, Ay, and Az = not fixed" are satisfied, the determination unit 203b can determine that it is in a constant speed state.

[0117] When the determination unit 203b determines that it is in a constant speed state, the estimation unit 203 estimates anomalies based on the detection results of the acceleration sensor 23. In other words, the estimation unit 203 estimates whether there are anomalies related to the wear of the speed reducer 22 based on the detection results of the acceleration sensor 23 and the detection results of the change amount sensor 24.

[0118] (Regarding the determination of non-constant speed state)

[0119] Next, the determination of the non-constant speed state will be described.

[0120] The determination unit 203b determines a non-constant speed state other than the constant speed state based on the combined value of the accelerations of each axis detected by the change amount sensor 24 and the gravitational acceleration. Specifically, when the combined value of each axis is inconsistent with the gravitational acceleration, the determination unit 203b determines an acceleration / deceleration state indicating that the arm is moving in an accelerating or decelerating manner as a non-constant speed state.

[0121] (Regarding the determination of acceleration / deceleration state)

[0122] In the acceleration / deceleration state, Rx, Ry, and Rz are not fixed. In addition, since the arm 4 moves, the directions of the accelerations of the three axes detected by the change amount sensor 24 are not fixed. That is, the respective values of Ax, Ay, and Az (= Gx, Gy, Gz) are not fixed.

[0123] Therefore, when the condition of "the combined value of Ax, Ay, and Az ≠ 9.8 m / s 2 " is satisfied, the determination unit 203b can determine that it is in an acceleration / deceleration state.

[0124] When the determination unit 203b determines that it is in an acceleration / deceleration state, the estimation unit 203 does not estimate anomalies.

[0125] (Regarding the determination of stop state)

[0126] When the combined value of each axis within a specified period by the determination unit 203b is consistent with the gravitational acceleration and the values of each axis within the specified period are constant, the stopped state is determined. When specifically described, in the case of the stopped state, since there is no acceleration or deceleration,

[0127] Rx = Ry = Rz = 0

[0128] Therefore, the above equations 3 to 5 are expressed as follows.

[0129] Ax = Gx

[0130] Ay = Gy

[0131] Az = Gz

[0132] Therefore, the combined value of Ax, Ay, and Az is 9.8 m / s 2 .

[0133] In addition, since the arm unit 4 does not move, the orientations of the accelerations of the three axes detected by the change amount sensor 24 do not change. Therefore, the values of Ax, Ay, and Az (= Gx, Gy, Gz) are constant.

[0134] That is, when the conditions that "the combined value of Ax, Ay, and Az = 9.8 m / s 2 " and "the values of Ax, Ay, and Az = constant" are satisfied, the determination unit 203b can determine that it is in the stopped state.

[0135] When the determination unit 203b determines that it is in the stopped state, the estimation unit 203 does not perform abnormal estimation.

[0136] (Hardware Structure of the State Monitoring Device 100)

[0137] Figure 4 is an explanatory diagram of the hardware structure of the state monitoring device 100. As Figure 4 shown, the state monitoring device 100 includes a CPU (Central Processing Unit) 401, a memory 402, an I / F (interface) 403, an acceleration sensor 23, and a change amount sensor 24. Each unit is connected by a bus 410.

[0138] The CPU 401 is responsible for the overall control of the state monitoring device 100. For example, the CPU 401 executes Figure 2 the respective processes of the first acquisition unit 201, the second acquisition unit 202, the estimation unit 203, and the notification unit 204 shown. The CPU 401 can also control the operations of the acceleration sensor 23 and the change amount sensor 24.

[0139] The memory 402 is a general term for storage devices such as ROM, RAM, USB (Universal Serial Bus) flash memory, SSD (Solid State Drive), etc. For example, Figure 2 the storage unit 210 shown is constituted by the memory 402.

[0140] The I / F 403 is a general term for an input I / F and an output I / F (including a communication I / F). For example, the second acquisition unit 202 acquires the angular velocity and acceleration of the arm unit 4 from the change amount sensor 24 via the I / F 403 (communication I / F).

[0141] In addition, various programs including the abnormality estimation program related to the present embodiment are stored in the memory 402. The CPU 401 realizes the functions of the first acquisition unit 201, the second acquisition unit 202, the estimation unit 203, and the notification unit 204 by executing the abnormality estimation program. That is, the first acquisition unit 201, the second acquisition unit 202, the estimation unit 203, and the notification unit 204 are realized by the CPU 401.

[0142] (Processing performed by the estimation control unit 200)

[0143] Figure 5 is a flowchart showing an example of the processing performed by the estimation control unit 200.

[0144] In Figure 5 , the estimation control unit 200 determines whether the abnormality estimation has started (step S501). The start timing of the abnormality estimation can be set to a preset timing (a specified timing several times a day) or a timing when an input of a start instruction from an operator exists.

[0145] The estimation control unit 200 stands by until the abnormality estimation starts (step S501: "No"), and if the abnormality estimation starts (step S501: "Yes"), it acquires the three-axis acceleration detected by the change amount sensor 24 (step S502).

[0146] Next, the estimation control unit 200 determines whether the arm unit 4 is in an acceleration / deceleration state (the combined value of Ax, Ay, and Az ≠ 9.8 m / s 2 )(step S503). When the arm unit 4 is in an acceleration / deceleration state (step S503: "Yes"), the estimation control unit 200 returns to step S502. On the other hand, when the arm unit 4 is not in an acceleration / deceleration state (step S503: "No"), the estimation control unit 200 determines whether it is in a stopped state ("the combined value of Ax, Ay, and Az = 9.8 m / s 2 " and "each value of Ax, Ay, and Az = constant") (step S504).

[0147] In the case of being in the stopped state (step S504: "Yes"), the estimation control unit 200 returns to step S502. On the other hand, in the case where the arm 4 is not in the stopped state (step S504: "No"), that is, in the case of being in the constant velocity state ("the combined value of Ax, Ay, and Az = 9.8 m / s 2 " and "each value of Ax, Ay, and Az = indefinite"), the abnormal estimation process is executed ( Figure 6 )(step S505), and a series of processes is ended.

[0148] (Processes performed by the estimation control unit 200 and the change amount sensor 24)

[0149] Figure 6 is a timing chart related to the abnormal estimation performed by the estimation control unit 200 and the change amount sensor 24. In addition, Figure 6 the process performed by the estimation control unit 200 shown is equivalent to Figure 5 the abnormal estimation process (step S505) shown.

[0150] In Figure 6 , the estimation control unit 200 issues a transmission request for the rotational speed of the arm 4 to the change amount sensor 24 (step S601). When the change amount sensor 24 receives this transmission request from the estimation control unit 200, it starts (step S602) and detects the angular velocity of the arm 4 (step S603).

[0151] Then, the change amount sensor 24 calculates the rotational speed of the arm 4 based on the detected angular velocity and the above formula 1 (step S604). Then, the change amount sensor 24 transmits the calculated rotational speed to the estimation control unit 200 (step S605) and ends the process. After issuing the transmission request for the rotational speed in step S601, the estimation control unit 200 acquires the vibration data detected by the acceleration sensor 23 (step S606).

[0152] Then, when the estimation control unit 200 acquires the rotational speed of the arm 4 from the change amount sensor 24 (step S607), it multiplies the number of teeth stored in the storage unit 210 by the rotational speed acquired in step S607 to calculate the target frequency (step S608). Then, the estimation control unit 200 extracts the vibration data at the target frequency (step S609). Next, the estimation control unit 200 estimates an abnormality related to gear wear (step S610). Then, the estimation control unit 200 notifies the estimation result (step S611) and ends a series of processes.

[0153] (Effects of the embodiment)

[0154] As described above, the state monitoring device 100 according to the present embodiment estimates an abnormality based on the detection result of the acceleration sensor 23 provided on the rotating shaft portion 20 (vibration data of the speed reducer 22) and the detection result of the change amount sensor 24 provided on the arm portion 4 (rotation speed of the arm portion 4). Thus, even without obtaining information from the mother machine, it is possible to estimate an abnormality of the speed reducer 22 with a simple structure.

[0155] In addition, the state monitoring device 100 according to the present embodiment estimates an abnormality based on the detection result of the acceleration sensor 23 provided on the rotating shaft portion 20 (vibration data of the speed reducer 22) and the detection result of the change amount sensor 24 provided on the arm portion 4 (acceleration of three axes of the arm portion 4). Thus, even without obtaining information from the mother machine, it is possible to estimate an abnormality based on the detection result of the acceleration sensor 23 at the best timing obtained from the acceleration of the three axes of the arm portion 4. Therefore, it is possible to estimate an abnormality of the speed reducer 22 with high precision using a simple structure.

[0156] In addition, the state monitoring device 100 according to the present embodiment calculates a target frequency based on the rotation speed of the arm portion 4 and the number of teeth of the gear, extracts data corresponding to the target frequency from the vibration data detected by the acceleration sensor 23, and estimates an abnormality based on the extracted data. Thus, the state monitoring device 100 can perform without large-scale operations such as FFT (Fast Fourier Transformation), and thus can reduce power consumption.

[0157] Therefore, the state monitoring device 100 can be applied to a simple device (such as an intelligent sensor) driven by a battery.

[0158] In addition, the state monitoring device 100 according to the present embodiment extracts data corresponding to the target frequency from the time series data of the vibration through filtering processing, and estimates whether an abnormality exists based on the comparison result between the extracted data and a specified threshold value. Thus, it is possible to estimate whether an abnormality exists with a simpler structure.

[0159] In addition, the state monitoring device 100 according to the present embodiment determines that the arm portion 4 is in a constant speed state based on the comparison result between the combined value of each axis of the three-axis acceleration of the arm portion 4 and the gravitational acceleration. Moreover, the state monitoring device 100 estimates whether an abnormality exists based on the detection result of the acceleration sensor 23 at the time point determined to be in the constant speed state. Thus, the accuracy of abnormality estimation can be improved.

[0160] In addition, when the combined value of the triaxial acceleration of the arm 4 within a specified period in the state monitoring device 100 according to the present embodiment is consistent with the gravitational acceleration and the values of each axis within the specified period are indeterminate, a constant velocity state is determined. Thus, the constant velocity state can be simply determined.

[0161] In addition, the state monitoring device 100 according to the present embodiment determines the non-constant velocity state of the arm 4 based on the combined value of the triaxial acceleration of the arm 4 and the gravitational acceleration, and does not estimate whether there is an abnormality in the non-constant velocity state. In the non-constant velocity state, it is impossible to estimate an abnormality with high accuracy. Therefore, by setting not to perform abnormality estimation, the accuracy of abnormality estimation can be improved.

[0162] In addition, when the combined value of the triaxial acceleration of the arm 4 in the state monitoring device 100 according to the present embodiment is inconsistent with the gravitational acceleration, the acceleration / deceleration state of the arm 4 is determined. Thus, the acceleration / deceleration state can be simply determined.

[0163] In addition, the state monitoring device 100 according to the present embodiment determines that the arm 4 is in a constant velocity state based on the comparison result between the combined value of the triaxial acceleration of the arm 4 and the gravitational acceleration. And the state monitoring device 100 calculates a target frequency based on the rotational speed of the arm 4 and the number of teeth of the gear in the constant velocity state. Moreover, the state monitoring device 100 extracts data corresponding to the target frequency from the time series data of the vibration detected by the acceleration sensor 23, and estimates whether there is an abnormality based on the extracted data. Thus, the constant velocity state can be simply determined, and the accuracy of abnormality estimation can be improved. In addition, the state monitoring device 100 does not require large-scale operations such as FFT, so the power consumption can be reduced. Therefore, the state monitoring device 100 can be applied to a simple device (such as a smart sensor) driven by a battery.

[0164] (Modification example of the embodiment)

[0165] Next, modification examples of the embodiment will be listed. In addition, in each of the following modification examples, descriptions of the content described in the above embodiment will be appropriately omitted. Also, it can be set as a structure in which the above embodiment is combined with the structures shown in the respective modification examples.

[0166] (Modification example 1)

[0167] In the above embodiment, the following example has been described: the state monitoring device 100 calculates a target frequency and extracts data corresponding to the target frequency from the time series data of the vibration detected by the acceleration sensor 23.

[0168] The state monitoring device 100 according to Modification 1 can also extract data corresponding to a target frequency by performing FFT analysis on the time-series data of vibrations detected by the acceleration sensor 23.

[0169] However, in Modification 1 as well, similar to the above-described embodiment, the state monitoring device 100 estimates an abnormality at the optimal timing (e.g., a constant-speed state) based on the detection result of the change amount sensor 24 provided on the arm portion 4 (the acceleration in three axes of the arm portion 4).

[0170] According to Modification 1, even without obtaining information from the mother machine, it is possible to perform abnormality estimation based on FFT analysis at the optimal timing obtained from the acceleration in three axes of the arm portion 4. Therefore, it is possible to perform FFT analysis to improve the estimation accuracy in the case of estimating an abnormality of the speed reducer 22.

[0171] (Modification 2)

[0172] In the above-described embodiment, the following example has been described: the acceleration sensor 23 is used as the first detection unit.

[0173] The state monitoring device 100 according to Modification 2 can also use an iron powder sensor as the first detection unit. The iron powder sensor is a sensor that detects the amount of iron powder (wear amount) contained in the grease in the speed reducer 22. Regarding the iron powder in the speed reducer 22, for example, the iron powder is likely to spread during the acceleration / deceleration state, so it is expected that the detection accuracy of the iron powder will be improved during the acceleration / deceleration state.

[0174] Therefore, the state monitoring device 100 determines the acceleration / deceleration state based on the detection result of the change amount sensor 24 (the acceleration in three axes of the arm portion 4), and at the determined timing, performs abnormality estimation based on the detection result of the iron powder sensor.

[0175] According to Modification 2, even without obtaining information from the mother machine, it is possible to perform abnormality estimation based on the detection result of the iron powder sensor at the optimal timing obtained from the acceleration in three axes of the arm portion 4. Therefore, it is possible to improve the accuracy related to the abnormality estimation of the speed reducer 22.

[0176] (Modification 3)

[0177] In the above-described embodiment, the following example has been described: the change amount sensor 24 is provided at a portion of the arm portion 4 that is closer to the base end side than the rotary shaft portion 20 disposed on the front end side.

[0178] The change amount sensor 24 according to Modification 3 can also be provided on the rotary shaft portion 20 disposed on the front end side of the arm portion 4.

[0179] When specifically described, the third rotation axis portion 20c is provided at one end (front end) of the boom 5, and thus is included in the boom 5. Therefore, in Modification 3, the second change amount sensor 24b is provided at the third rotation axis portion 20c included in the boom 5.

[0180] In addition, the fourth rotation axis portion 20d is provided at one end (front end) of the arm 7, and thus is included in the arm 7. Therefore, in Modification 3, the third change amount sensor 24c is provided at the fourth rotation axis portion 20d included in the arm 7.

[0181] Both the second change amount sensor 24b and the third change amount sensor 24c are sensors capable of detecting the acceleration of three axes and the angular velocity of three axes. Thus, the second change amount sensor 24b not only substitutes for the function of detecting the rotational speed of the boom 5 (the function of the second detection unit), but also substitutes for the function of detecting the vibration of the third speed reducer 22c (the gear at the joint portion of the boom 5 and the arm 7) (the function of the first detection unit).

[0182] Similarly, the third change amount sensor 24c not only substitutes for the function of detecting the rotational speed of the arm 7 (the function of the second detection unit), but also substitutes for the function of detecting the vibration of the fourth speed reducer 22d (the gear at the joint portion of the arm 7 and the bucket 9) (the function of the first detection unit).

[0183] According to Modification 3, the number of sensors as the first detection unit can be reduced, and thus a simpler structure can be achieved.

[0184] (Modification 4)

[0185] In the above-described embodiment, the following example has been described: directly notifying the estimation result of the abnormality estimation.

[0186] In Modification 4, the following example is described: predicting an abnormality based on the actual performance data obtained by performing the abnormality estimation. Hereinafter, an example of predicting an abnormality using a learned model will be described.

[0187] In Modification 4, the generation of a learned model is described in the case where the rotational speed of the arm portion 4 and the vibration data of the speed reducer 22 are used as input samples, and the period until the maintenance of the speed reducer 22 (usable period: remaining 1 month, remaining 2 months, etc.) is used as an output sample.

[0188] The learned model is generated by a learning device such as a personal computer. The learning device uses a pre-prepared data set to learn the parameters of a classification model such as a neural network. The data set uses the actual data of various detection results and estimation results of the state monitoring device 100. The classification model includes an input unit, a feature quantity calculation unit, a classification unit, and an output unit. The input unit outputs the rotational speed of the arm 4 and the vibration data of the reduction gear 22 that are input as a vector to the feature quantity calculation unit. The input unit constitutes the input layer of the neural network.

[0189] The feature quantity calculation unit and the classification unit are the intermediate layers of the neural network. The output unit is the output layer of the neural network. The feature quantity calculation unit transforms the vector input from the input unit into a low-dimensional feature vector and outputs it to the classification unit. The classification unit transforms the feature vector input from the feature quantity calculation unit into a P-dimensional vector representing the posterior probability of the service life represented by the feature vector. P is the number of service lives to be estimated.

[0190] The learning device obtains a learning data set obtained by associating the rotational speed of the arm 4 and the vibration data of the reduction gear 22 as input samples. When the number of service lives in the data set is set to P, the rotational speed of the arm 4 and the vibration data of the reduction gear 22 are represented by a P-dimensional one-hot vector.

[0191] The learning device uses the obtained learning data set to learn the parameters of the classification model so that when the rotational speed of the arm 4 and the vibration data of the reduction gear 22 are input, a P-dimensional vector representing the posterior probability of the service life is output. Specifically, the learning device uses the obtained data set to learn the parameters of the classification model. At this time, the learning device updates the parameters of the feature quantity calculation unit and the classification unit in the classification model.

[0192] More specifically, the learning device updates each parameter by the gradient descent method in such a way that the loss function is minimized using the calculation result of the classification model. For example, the loss function represents the cross-entropy error between the output value of the classification model and the output sample of the data set. The learning device ends the learning process and generates a learned model when the evaluation value of the loss function is lower than a specified threshold or when the learning process has been repeated a specified number of times.

[0193] By inputting the rotational speed of the arm 4 and the vibration data of the reduction gear 22 into the learned model, it is possible to calculate an estimated value and output the service life with a high estimated value.

[0194] The generated learned model can also be stored in another device (e.g., a server) different from the state monitoring device 100. In this case, when the state monitoring device 100 detects the rotational speed of the arm 4 and the vibration data of the speed reducer 22, it sends the detection result to the other device storing the learned model. This other device determines the available period based on the detection result and outputs the determined available period. The output available period is, for example, displayed on the display of the construction machine 1 or on the personal computer configured in the maintenance factory of the construction machine 1.

[0195] In addition, the learned model can also be stored in the state monitoring device 100. In this case, the state monitoring device 100 only needs to determine the available period based on the detection result and output the determined available period.

[0196] According to Modification Example 4, the learned model can be used to determine the available period based on the rotational speed of the arm 4 and the vibration data of the speed reducer 22 detected by the state monitoring device 100. In addition, even without obtaining information from the mother machine, the abnormality of the speed reducer 22 can be predicted with a simple structure.

[0197] In addition, in Modification Example 4, an example in which the output sample is set as the available period is described, but it is not limited thereto, and the output sample can also be set as the replacement period (year, month, etc.).

[0198] (Other Examples)

[0199] In the above-described embodiment, an example in which the speed reducer 22 is a gear mechanism having a plurality of gears is described. However, the speed reducer 22 may also have pins (internal gear pins) in addition to gears. For example, the speed reducer 22 may be configured such that a plurality of pin grooves are formed on the inner peripheral surface of the housing, the plurality of pin grooves respectively hold a plurality of internal gear pins, and a gear mechanism (e.g., one or more oscillating gears) in the housing meshes with the plurality of internal gear pins.

[0200] The pin grooves or pins can also be regarded as part of the gear mechanism. For example, the plurality of pin grooves can be called gears, and each pin can be called a tooth. For example, the number of teeth can also include the number of pins. In addition, when the number of teeth is set not to include the number of pins, the target frequency is obtained by multiplying the rotational speed of the arm 4, the number of teeth of the gear, and the number of pins.

[0201] In the above-described embodiment, an example in which the state monitoring device 100 is applied to the construction machine 1 is described. However, the state monitoring device 100 can also be applied to a robot (e.g., a 6-axis robot). The robot is, for example, an industrial robot.

[0202] In this case, the state monitoring device 100 may detect a first physical quantity related to the wear of a gear provided at a joint portion of the robotic arm and a second physical quantity related to the motion state of the front end side of the robotic arm, and estimate whether there is an abnormality related to the wear of the gear based on these detection results.

[0203] As described above, the embodiments of the present invention have been described in detail with reference to the accompanying drawings. However, the specific structure is not limited to this embodiment, and also includes designs and the like within the scope not departing from the gist of the present invention.

[0204] For example, in the embodiments disclosed in this specification, in the embodiments where multiple functions are dispersedly arranged, a part or all of these multiple functions may be integrally arranged. Conversely, in the embodiments where multiple functions can be integrally arranged, these multiple functions may be arranged in a dispersed manner in part or in whole. Whether the functions are integrated or dispersed, as long as it is configured to be able to achieve the object of the invention.

[0205] In the embodiment, as a mechanical element provided at the joint portion of the arm portion 4, a gear is taken as an example for description, but it is not limited to a gear. For example, as a mechanical element, it may also be a bearing or a motor provided at the joint portion, etc.

[0206] Moreover, in the embodiment, as the first physical quantity related to the mechanical element, the vibration of the gear is taken as an example for description, but it is not limited to this case. For example, the motor current of the motor (mechanical element) may also be used as the first physical quantity. In this case, for example, the rotational speed of the arm portion 4 may also be used as the second physical quantity related to the motion state of the arm portion 4. In this case, for example, the amplitude value of the frequency of the motor current determined according to the rotational speed may also be monitored to estimate the fault omen (the state of the mechanical element) of the motor.

[0207] A program (for example, a state monitoring program) for implementing the functions of the device (for example, the state monitoring device 100) related to the above-described embodiments may also be stored in a computer-readable storage medium, and the computer system may be made to read and execute the program stored in this storage medium for processing.

[0208] In addition, the "computer system" may also include an operating system (OS: Operating System) or hardware such as peripheral devices. Further, the "computer-readable storage medium" refers to a writable non-volatile memory such as a floppy disk, an optical disk, a ROM (Read Only Memory), a flash memory, a removable medium such as a DVD (Digital Versatile Disc), or a storage device such as a hard disk built into the computer system.

[0209] Furthermore, the "computer-readable storage medium" also includes a medium that holds a program for a certain period of time, such as an information processing device when a program is transmitted via a network such as the Internet or a communication line such as a telephone line, or a volatile memory (e.g., DRAM (Dynamic Random Access Memory)) inside the computer system of a client. In addition, the above-mentioned program can also be transmitted from a computer system that stores the program in a storage device or the like to other computer systems via a transmission medium or by a transmission wave in the transmission medium.

[0210] Here, the "transmission medium" for transmitting a program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication wire) such as a telephone line.

[0211] In addition, the above-mentioned program can also be a program for implementing a part of the above-mentioned functions. And the above-mentioned program can also be a program that can implement the above-mentioned functions through combination with a program already stored in the computer system, that is, a so-called differential file (differential program).

[0212] Industrial Applicability

[0213] According to the present invention, the state of mechanical elements (e.g., abnormality of gears) can be estimated with a simple structure.

[0214] Description of Reference Numerals

[0215] 1: Construction machine; 2: Main body; 4: Arm part; 5: Boom; 7: Dipper arm; 9: Bucket; 20: Rotating shaft part; 22: Reducer; 23: Acceleration sensor; 24: Variation sensor; 100: State monitoring device; 200: Estimation control unit; 201: First acquisition unit; 202: Second acquisition unit; 203: Estimation unit; 203a: Calculation unit; 203b: Determination unit; 204: Notification unit.

Claims

1. A state monitoring device, comprising: a first detection unit, which is provided at a joint portion of a rotatable arm and detects a first physical quantity related to a mechanical element provided at the joint portion; a second detection unit, which is provided at a front end side of the arm different from a base end side where the joint portion is disposed and detects a second physical quantity related to a motion state of the arm; and an estimation unit, which estimates a state of the mechanical element based on the first physical quantity detected by the first detection unit and the second physical quantity detected by the second detection unit.

2. The state monitoring device according to claim 1, wherein the mechanical element is a gear provided at the joint portion, the first physical quantity is vibration of the gear, the second physical quantity is at least one physical quantity of acceleration and angular velocity of the arm, the estimation unit has a calculation unit, and the calculation unit calculates a specific frequency of the vibration based on a detection result of the second physical quantity during a specified period when the arm is in motion and the number of teeth of the gear; the estimation unit further estimates the state of the gear by using the calculated specific frequency and the detection result of the first physical quantity during the specified period.

3. The state monitoring device according to claim 2, wherein the estimation unit extracts data corresponding to the calculated specific frequency from time series data of the detection result of the first physical quantity during the specified period, and estimates the state of the gear based on the extracted data.

4. The state monitoring device according to claim 3, wherein the estimation unit performs a filtering process for extracting data corresponding to the specific frequency from the time series data of the detection result of the first physical quantity, and estimates the state of the gear based on a comparison result between the extracted data and a specified threshold.

5. The state monitoring device according to any one of claims 1 to 4, wherein the second physical quantity is a three-axis acceleration of the arm, the estimation unit has a determination unit, and the determination unit determines whether it is in a constant speed state indicating that the arm is operating in a constant speed manner based on a comparison result between a combined value of each axis of the three-axis acceleration and gravitational acceleration; the estimation unit estimates the state of the mechanical element based on the detection result of the first detection unit at a time point when it is determined to be in the constant speed state.

6. The state monitoring device according to claim 5, wherein when the combined value of each axis during a specified period is consistent with gravitational acceleration and the values of each axis during the specified period are indefinite, the determination unit determines that the arm is in the constant speed state.

7. The state monitoring device according to claim 5 or 6, wherein the determination unit determines a non-constant speed state other than the constant speed state based on the combined value of each axis and gravitational acceleration; the estimation unit does not estimate the state of the mechanical element in the non-constant speed state.

8. The state monitoring device according to claim 7, wherein In a case where the combined value of each axis is inconsistent with the gravitational acceleration, the determination unit determines an acceleration / deceleration state indicating that the arm is operating in an accelerating or decelerating manner as the non-uniform velocity state.

9. The state monitoring device according to claim 1, wherein the mechanical element is a gear provided in the joint portion, the first physical quantity is the vibration of the gear, the second physical quantity includes the rotational speed of the arm and the three-axis acceleration of the arm, the estimation unit includes: a determination unit that determines whether it is in a uniform velocity state indicating that the arm is operating in a uniform velocity manner based on a comparison result between the combined value of each axis of the three-axis acceleration and the gravitational acceleration; and a calculation unit that calculates a specific frequency of the vibration based on information including at least the rotational speed of the arm and the number of teeth of the gear at a time point determined to be in the uniform velocity state, and the estimation unit extracts data corresponding to the calculated specific frequency from the time-series data of the detection result of the first physical quantity and estimates the state of the gear based on the extracted data.

10. A computer-readable storage medium storing a program that causes a computer to function as a state monitoring device, the program causing the computer to function as a first acquisition unit, a second acquisition unit, and an estimation unit, Among them, the first acquisition unit acquiring the first physical quantity from a first detection unit that is provided in a joint portion of a rotatable arm and detects a first physical quantity related to a mechanical element provided in the joint portion, the second acquisition unit acquiring the second physical quantity from a second detection unit that is provided on a front end side of the arm different from a base end side where the joint portion is disposed and detects a second physical quantity related to a motion state of the arm, the estimation unit estimating the state of the mechanical element based on the first physical quantity acquired by the first acquisition unit and the second physical quantity acquired by the second acquisition unit.

Images