WORK MACHINE

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2024-213319, filed with Japan Patent Office on Dec. 6, 2024, the entire contents of which are incorporated herein by reference.

BACKGROUND

1. Technical Field

The present invention relates to a work machine.

2. Description of Related Art

Existing technologies allow a work machine to identify its current situation and issue warnings depending on its current situation. For example, there is a technique whereby a warning is issued based on the weight of the load on a work machine's attachment.

SUMMARY

According to an embodiment of the present invention, a work machine includes: a sensor configured to detect information about stress or load occurring with respect to the work machine; and a controller configured to issue a notice when the stress or load occurring in a predetermined part of the work machine, calculated based on the information obtained from the sensor, is greater than a predetermined value in magnitude.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing an example of a work machine control system according to a first embodiment;

FIG. 2 is a side view of the work machine according to the first embodiment;

FIG. 3 is a diagram schematically showing a sample structure of the work machine according to the first embodiment;

FIG. 4 is a diagram illustrating loads produced in varying parts of the work machine according to the first embodiment;

FIG. 5 is a graph for explaining predetermined values, based on which a determining part according to the first embodiment determines whether a certain amount of stress is produced;

FIG. 6 is a graph illustrating a relationship between stress amplitude and the number of times the stress amplitudes occur before a fracture occurs;

FIG. 7 is a graph for explaining how the determining part according to the first embodiment determines a cumulative damage level value in a predetermined part;

FIG. 8 is a diagram illustrating a display screen shown on a display device by a notifying part according to the first embodiment;

FIG. 9 is a diagram illustrating a display screen shown on a management device based on information sent from the notifying part according to the first embodiment;

FIG. 10 is a flowchart illustrating a process of issuing a notice in the work machine according to the first embodiment; and

FIG. 11 is a schematic diagram illustrating a sample structure of an operation system according to a second embodiment.

DETAILED DESCRIPTION

When a work machine is at work, different parts constituting the work machine experience varying loads. Furthermore, every part that constitutes at least part of the work machine has a different likelihood of getting damaged from load. This makes it difficult for the work machine's operator to predict whether or not a certain part of the work machine is likely to be damaged. It is therefore preferable to issue an appropriate notice when there is a possibility of damage occurring in a part that constitutes at least part of the work machine.

In view of the foregoing, the present invention aims to achieve improved safety by issuing appropriate notices.

According to an embodiment of the present invention, improved safety can be achieved by issuing appropriate notices.

Embodiments of the present disclosure will be described below with reference to the accompanying drawings. The embodiments described below are examples, and the present invention is by no means limited to them. All features and/or combinations of features in the following embodiments of the present disclosure are not necessarily essential to the present invention. In addition, parts or components in the drawings that are the same or substantially the same will be assigned the same or substantially the same reference codes so that redundant description can be spared.

The work machine 100 according to the following embodiments of the present disclosure is an excavator. The work machine 100 may also be a machine other than an excavator, such as a construction machine (for example, a crane), an asphalt paver, a forklift, a robot, and so forth. Although the drawings will show the work machine 100 as an excavating machine having a bucket 6 as its end attachment, the work machine 100 may also be an application machine such as a forestry machine with an end attachment other than a bucket 6. Furthermore, the work machine 100 may be a crawler crane equipped with: a lower travel body; an upper rotary body; and an attachment provided as part of the upper rotary body.

First Embodiment

First, an overview of a work machine management system SYS (an example of a work machine control system) according to the first embodiment will be described with reference to FIG. 1. FIG. 1 is a schematic diagram showing an example of the work machine management system SYS according to the first embodiment.

<Devices/Equipment Constituting Remote Operation System>

As shown in FIG. 1, the work machine management system SYS according to the first embodiment includes a work machine 100, a management device 700, and a mobile communication The architecture of the work machine terminal 500. management system SYS shown in FIG. 1 is simply an example and not limited to this example.

The work machine 100, the management device 700, and the mobile communication terminal 500 are connected via a communication network NW so that data can be transmitted and received among them.

The work machine 100 and the mobile communication terminal 500 are capable of wireless communication. The work machine 100 can also transmit and receive data with devices connected to the communication network NW (for example, a remote operation room RC, the management device 700, the mobile communication terminal 500, etc.).

The mobile communication terminal 500 is an information processing device that a person who performs maintenance work for the work machine 100 (hereinafter “worker”) carries with him/her. The worker may, for example, belong to the business that sells the work machine 100, inspect the work machine 100, replace its parts, and so on.

The management device 700 is, for example, a server computer (cloud server) or an edge server. The management device 700 is typically a fixed terminal device, but may also be a portable terminal device (for example, a laptop computer, a tablet, a smartphone, etc.). The management device 700 is installed, for example, in a control center that manages, for example, a job site. The management device 700 is an information processing device that a person who manages the work machine 100 (e.g., the owner of the work machine 100) holds. Although this embodiment shows an example in which the management device 700 is installed in a control center, the functions of the management device may be implemented as cloud services, for example.

The work machine 100 is located at a job site. The work machine 100 sends information about the work machine 100 and the job site, to the management device 700. This allows the management device 700 to check the status of the work machine 100 and the situation at the job site based on the information from the work machine 100. Note that, according to this embodiment, the device that performs measurements at the job site is by no means limited to the work machine 100. That is, different types of devices can also be used, such as a fixed-point measurement device located at the job site, a drone flying over the job site, or an image capturing device that can be carried by the operator.

Furthermore, if necessary, the work machine 100 sends alerts and other messages, corresponding to the current situation of the work machine 100, to the mobile communication terminal 500. The worker identifies the current situation of the work machine 100 by checking the alerts and other messages displayed on the mobile communication terminal 500. The worker performs maintenance services, management, etc, for the work machine 100 when necessary.

The work machine management system SYS may include one or more work machines 100. This allows the work machine management system SYS to provide information about the job site to the management device 700 through one or more work machines 100.

<Explanation of Structure of Work Machine>

First, an overview of the work machine 100 of this embodiment will be described with reference to FIG. 2. FIG. 2 is a side view of the work machine 100 according to the first embodiment.

Referring to FIG. 2, “+X” indicates one direction on an X axis that constitutes part of a three-dimensional Cartesian coordinate system, and “−X” is the opposite direction (not shown) on the X axis. “+Y” indicates one direction on an Y axis that constitutes part of the three-dimensional Cartesian coordinate system, and “−Y” is the opposite direction (not shown) on the Y axis. “+Z” indicates one direction on a Z axis that constitutes part of the three-dimensional Cartesian coordinate system, and “−Z” is the opposite direction (not shown) on the Z axis. In FIG. 2, “+X” relative to the work machine 100 is defined as toward the front of the work machine 100, and “−X” relative to the work machine 100 is defined as toward the rear of the work machine 100. “+Y” relative to the work machine 100 is defined as toward the left side of the work machine 100, and “−Y” relative to the work machine 100 is defined as toward the right side of the work machine 100. “+Z” relative to the work machine 100 is defined as toward the upper side of the work machine 100, and “−Z” relative to the work machine 100 is defined as toward the lower side of the work machine 100. The same applies to the rest of the drawings.

The work machine 100 includes: a lower travel body 1; an upper rotary body 3 that is rotatably mounted on the lower travel body 1 via a rotary mechanism 2; an attachment AT for performing various tasks; and an operation room 10. The operation room 10 is also referred to as a “cabin” or “cab.” The front of the work machine 100 (upper rotary body 3) is the side of the work machine 100 where the attachment AT is attached to the upper rotary body 3, viewed from directly above along the rotation axis of the upper rotary body 3. Furthermore, the left, the right, and the rear of the work machine 100 (upper rotary body 3) are the left, the right, and the rear, respectively, seen from the operator seated in the operator's seat in the operation room 10.

The lower travel body 1 includes, for example, left and right crawlers 1C forming a pair. To be more specific, the crawlers 1C include a left crawler and a right crawler. The left crawler is driven by a left travel hydraulic motor 2ML (see FIG. 3), and the right crawler is driven by a right travel hydraulic motor 2MR (see FIG. 3). The left travel hydraulic motor 2ML is a travel-drive part that drives the left crawler, which is a dependent part, by allowing the left crawler to rotate. The right travel hydraulic motor 2MR is a travel-drive part that drives the right crawler, which is a dependent part, by allowing the right crawler to rotate. The travel-drive parts may be electric motors as well.

A boom 4 is rotatably attached to a center-front part of the upper rotary body 3. An arm 5 is rotatably attached to the tip of the boom 4. A bucket 6 is rotatably attached to the tip of the arm 5. In the illustrated example, the boom 4, the arm 5, and the bucket 6 constitute an excavating attachment, which is an example of the attachment AT. The boom 4, the arm 5, and the bucket 6 are driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, respectively.

The bucket 6 is an example of a work tool (an end attachment). The bucket 6 is used, for example, for excavation. Instead of the bucket 6, other work tools may be attached to the tip of the arm 5 depending on the details of job. Other work tools may be different types of buckets, such as a large bucket, a sloping bucket, a dredging bucket, and so forth. For example, different types of work tools other than buckets may be used, such as a mixer, a breaker, a grapple, a lifting magnet, and so forth may be used. The excavating attachment may be equipped with a bucket tilting mechanism.

A rotary hydraulic motor 2A, a left travel hydraulic motor 2ML, a right travel hydraulic motor 2MR, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 are hydraulic actuators driven by hydraulic oil discharged from a hydraulic pump.

Note that, in the work machine 100, some or all of the dependent parts, such as the lower travel body 1, the upper rotary body 3, the boom 4, the arm 5, and the bucket 6, may be driven electrically. In other words, the work machine 100 may be a hybrid excavator, an electric excavator, or the like, in which some or all of the dependent parts are driven by electric actuators.

Image capturing devices S6 are provided in the upper rotary body 3 and take pictures around the work machine 100, thus obtaining image information showing the surroundings of the work machine 100. In the illustrated example, the image capturing devices S6 include a front camera S6F, a left camera S6L, a right camera S6R, and a back camera S6B.

The front camera S6F is a camera that takes pictures in front of the work machine 100 and provided outside the operation room 10. For example, the front camera S6F may be provided on the roof of the operation room 10, on the side of the boom 4, and so forth. The left camera S6L takes pictures to the left of the work machine 100. The right camera S6R takes pictures to the right of the work machine 100. The back camera S6B takes pictures behind the work machine 100. To be more specific, the front camera S6F, the left camera S6L, the right camera S6R, and the back camera S6B are all monocular wide-angle cameras with image capturing elements such as charge couple devices (CCDs), complementary metal oxide semiconductors (CMOSs), and so forth. Image data taken by these cameras is input to a controller 30. Images taken by the image capturing devices S6 may also be output to a display device D1 (see FIG. 3).

In the illustrated example, the front camera S6F is attached to the roof of the operation room 10, the left camera S6L is attached to a top left edge part of the upper rotary body 3, the right camera S6R is attached to a top right edge part of the upper rotary body 3, and the back camera S6B is attached to a top rear edge part of the upper rotary body 3.

The image capturing device S6 may constitute an object detecting device that detects objects around the work machine 100. The object detecting device may be a device other than a camera. For example, the object detecting device may be a LiDAR. A LiDAR generally refers to a device that can measure the distance between the LiDAR (laser source) and a group of one million or more points within the device's monitoring range. The object detecting device may also be another device that can measure the distance to an object, such as a stereo camera, a range imaging camera, a millimeter-wave radar, and so forth. When a millimeter-wave radar or the like is used as the object detecting device, the object detecting device may transmit multiple signals (e.g., laser beams) toward an object and receive their reflected signals to determine the direction of and the distance to the object. Alternatively, the object detecting device may be a combination of two or more types of devices. For example, the object detecting device may be a combination of an image capturing device and a LiDAR, a combination of an image capturing device and a millimeter-wave radar, or a combination of an image capturing device and a stereo camera.

The controller 30 is an example of a control device. The controller 30 is, for example, a computer including a CPU, a volatile memory device, a non-volatile memory device, various input/output interfaces, etc. The controller 30 implements various functions by, for example, reading programs from the non-volatile memory device, loading them in the volatile memory device, and having the CPU execute them. In the illustrated example, the controller 30 is structured to implement various functions to control the work machine 100. The various functions may include, for example, a machine guidance function to guide the operator in manual maneuvering of the work machine 100. The various functions may also include a contact-avoiding function to move or stop the work machine 100 automatically or autonomously so as to prevent the work machine 100 from coming into contact with objects in the monitoring range around the work machine 100.

The boom angle sensor S1 detects the rotating angle of the boom 4. According to this embodiment, the boom angle sensor S1 is an acceleration sensor that can detect changes in the rotating angle of the boom 4 (hereinafter referred to as “boom angle”), relative to the upper rotary body 3, per unit time. The boom angle sensor S1 can detect: the angular velocity of the boom 4, which indicates, for example, a change in the boom angle; and the angular acceleration of the boom 4, which indicates the magnitude (proportion) of that change. For example, the boom angle is at its minimum when the boom 4 is lowered to its lowest position and increases as the boom 4 is raised.

The arm angle sensor S2 detects the rotating angle of the arm 5. According to this embodiment, the arm angle sensor S2 is an acceleration sensor that can detect the rotating angle of the arm 5 relative to the boom 4 (hereinafter referred to as “arm angle”). The arm angle sensor S2 can detect: the angular velocity of the arm 5, which indicates, for example, a change in the arm angle; and the angular acceleration of the arm 5, which is the proportion of that change. For example, the arm angle is at its minimum when the arm 5 is completely closed and increases as the arm 5 opens.

The bucket angle sensor S3 detects the rotating angle of the bucket 6. According to this embodiment, the bucket angle sensor S3 is an acceleration sensor that can detect the rotating angle of the bucket 6 relative to the arm 5 (hereinafter referred to as the “bucket angle”). The bucket angle sensor S3 can detect: the angular velocity of the bucket 6, which indicates, for example, a change in the bucket angle; and the angular acceleration of the bucket 6, which is the proportion of that change. For example, the bucket angle is at its minimum when the bucket 6 is completely closed and increases as the bucket 6 opens.

The boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3 have only to be sensors (for example, posture sensors) wherefrom information about the attachment's posture can be obtained. The boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3 may be, for example, an inertial measurement unit (IMU), a six-axis sensor, a potentiometer using a variable resistor, a stroke sensor for detecting the amount of stroke of applicable hydraulic cylinders, a rotary encoder for detecting the rotating angle about a connecting pin, a gyro sensor, a combination of an acceleration sensor and a gyro sensor, and so forth. With this embodiment, an example will be described in which the boom angle, the arm angle, and the bucket angle are acquired as information about the posture of the work machine 100 (hereinafter “posture information”). However, the posture information is by no means limited to the boom angle, the arm angle, and the bucket angle, and may relate to least one of the boom angle, the arm angle, and the bucket angle. The posture information may also be image information that captures the posture of the attachment AT in a visible fashion.

A detection signal associated with the boom angle is obtained by the boom angle sensor S1, a detection signal associated with the arm angle is obtained by the arm angle sensor S2, and a detection signal associated with the bucket angle is obtained by the bucket angle sensor S3. These detection signals are input into the controller 30. The detection signals may include angular velocities in addition to angles.

The body angle sensor S4 detects the tilting state of the body (the lower travel body 1 or the upper rotary body 3) of the work machine 100 relative to a horizontal plane. The body angle sensor S4 is attached, for example, to the upper rotary body 3, and detects the tilting angle of the work machine 100 (i.e., the upper rotary body 3) about two axes, that is, the tilting angle of the work machine 100 in the front-to-rear direction and in the left-to-right direction. The body angle sensor S4 may be, for example, an acceleration sensor, a six-axis sensor, an IMU, or the like. A detection signal that indicates the tilting angle detected by the body angle sensor S4 is input to the controller 30.

The rotation sensor S5 outputs information about the rotation of the upper rotary body 3. The rotation sensor S5 detects, for example, the rotation angular velocity and the rotation angular acceleration of the upper rotary body 3 relative to the lower travel body 1. The rotation sensor S5 may also detect the rotation angle. The rotation sensor S5 may be, for example, a gyro sensor, a resolver, a rotary encoder, or the like. Detection signals that indicate the rotation angle, the rotation angular velocity, and the rotation angular acceleration of the upper rotary body 3 detected by the rotation sensor S5 are input to the controller 30.

A boom rod pressure sensor S7R and a boom bottom pressure sensor S7B are attached to the boom cylinder 7. An arm rod pressure sensor S8R and an arm bottom pressure sensor S8B are attached to the arm cylinder 8. A bucket rod pressure sensor S9R and a bucket b bottom pressure sensor S9B are attached to the bucket cylinder 9. The boom rod pressure sensor S7R, the boom bottom pressure sensor S7B, the arm rod pressure sensor S8R, the arm bottom pressure sensor S8B, the bucket rod pressure sensor S9R, and the bucket bottom pressure sensor S9B are examples of sensors for obtaining information about the stress or load occurring with respect to the work machine 100, and may be collectively referred to as “cylinder pressure sensors.”

The boom rod pressure sensor S7R detects the rod-side oil chamber pressure in the boom cylinder 7 (hereinafter “boom rod pressure”). The boom bottom pressure sensor S7B detects the bottom-side oil chamber pressure in the boom cylinder 7 (hereinafter “boom bottom pressure”). The arm rod pressure sensor S8R detects the rod-side oil chamber pressure in the arm cylinder 8 (hereinafter “arm rod pressure”). The arm bottom pressure sensor S8B detects the bottom-side oil chamber pressure in the arm cylinder 8 (hereinafter “arm bottom pressure”). The bucket rod pressure sensor S9R detects the rod-side oil chamber pressure in the bucket cylinder 9 (hereinafter “bucket rod pressure”). The bucket bottom pressure sensor S9B detects the bottom-side oil chamber pressure in the bucket cylinder 9 (hereinafter “bucket bottom pressure”).

A positioning device PS measures the position of the upper rotary body 3. The positioning device PS is, for example, a global navigation satellite system (GNSS) compass, which detects the position and orientation of the upper rotary body 3. A detection signal that i indicates the position and orientation of the upper rotary body 3 is input to the controller 30. A function to detect the orientation of the upper rotary body 3 may be implemented using an azimuth sensor provided in the upper rotary body 3. The positioning device PS according to this embodiment measures the current position of the work machine 100 using a reference coordinate system that allows world-wide positioning of the work machine 100.

The reference coordinate system is, for example, a world positioning system that can identify locations on the Earth's surface. The world positioning system is a three-dimensional Cartesian XYZ coordinate system with: an origin at the Earth's center of gravity; an X axis extending toward the intersection of the Greenwich Meridian and the equator; a Y axis pointing toward 90 degrees east longitude; and a Z axis pointing toward the north pole.

The operation room 10 is a compartment to be occupied by the operator of the work machine 100, and located in a front left part of the upper rotary body 3. However, if the work machine 100 is maneuvered from a remote location, or if the work machine 100 runs fully automatically, the operation room 10 may be omitted.

The communication device T1 communicates with outside devices/equipment through communication networks such as a mobile communication network, a satellite communication network, the Internet, and so forth. The communication device T1 may be, for example: a mobile communication module compatible with mobile communication standards such as long term evolution (LTE), 4th generation (4G), and 5th generation (5G); a communication module compatible with short-range wireless communication standards such as Wi-Fi (registered trademark) and Bluetooth (registered trademark); and a satellite communication module for connecting with a satellite communication network.

The work machine 100 runs the actuators in accordance with the way the operator in the operation room 10 maneuvers the work machine 100, drives dependent parts such as the lower travel body 1, the upper rotary body 3, the boom 4, the arm 5, and the bucket 6.

Alternatively, the work machine 100 may be structured such that it can be maneuvered from a remote location, outside the work machine 100. When the work machine 100 is maneuvered from a remote location, the inside of the operation room 10 may be unmanned.

In addition, the work machine 100 may run the actuators automatically, regardless of the details of the operator's maneuvering of the work machine 100. This allows the work machine 100 to implement a function to allow at least some of the dependent parts such as the lower travel body 1, the upper rotary body 3, the boom 4, the arm 5, and the bucket 6 to move automatically. This function is also known as a “machine control function.”

FIG. 3 is a diagram schematically showing a sample structure of the work machine 100 of this embodiment. In FIG. 3, the double line, the bold solid lines, the bold dashed line, and the dotted lines are a mechanical power transmission system, hydraulic oil lines, pilot lines, and an electrical control system, respectively.

The drive system of the work machine 100 includes an engine 11, a regulator 13, a main pump 14, and a control valve unit 17. The hydraulic drive system of the work machine 100 also includes hydraulic actuators such as the rotary hydraulic motor 2A, the left travel hydraulic motor 2ML, the right travel hydraulic motor 2MR, the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, and so forth.

The engine 11 is an example of a drive source for the work machine 100, and mounted, for example, in a rear part of the upper rotary body 3. The drive source for the work machine 100 may be a combination of: a power source such as a battery or a fuel cell; and an electric motor. To be more specific, the engine 11 rotates at a predetermined number of rotations per unit time, under direct or indirect control of the controller 30, driving the main pump 14 and a pilot pump 15. The engine 11 is, for example, a diesel engine fueled by diesel. The engine 11 may also be a gasoline engine, a hydrogen engine, and so forth.

The regulator 13 controls the amount of discharge from the main pump 14. For example, the regulator 13 controls the amount of discharge from the main pump 14 by adjusting the angle (tilting angle) of the swash plate of the main pump 14 in accordance with control commands from the controller 30.

Similar to the engine 11, the main pump 14 is mounted, for example, in a rear part of the upper rotary body 3, and supplies hydraulic oil to the control valve unit 17 via the hydraulic oil line. In the illustrated example, the main pump 14 is a variable displacement hydraulic pump.

The control valve unit 17 is one of the hydraulic control devices that control the hydraulic system in the work machine 100. In the illustrated example, the control valve unit 17 includes control valves 171 to 176. The control valve unit 17 is structured such that the hydraulic oil discharged from the main pump 14 can be supplied, selectively, to one or more hydraulic actuators via the control valves 171 to 176. The control valves 171 to 176 control the flow rate of hydraulic oil from the main pump 14 to the hydraulic actuators and the flow rate of hydraulic oil from the hydraulic actuators to the hydraulic oil tank. The hydraulic actuators include the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, the left travel hydraulic motor 2ML, the right travel hydraulic motor 2MR, and the rotary hydraulic motor 2A. To be more specific, the control valve 171 is associated with the left travel hydraulic motor 2ML, the control valve 172 is associated with the right travel hydraulic motor 2MR, and the control valve 173 is associated with the rotary hydraulic motor 2A. Likewise, the control valve 174 is associated with the bucket cylinder 9, the control valve 175 is associated with the boom cylinder 7, and the control valve 176 is associated with the arm cylinder 8.

The pilot pump 15 is an example of a pilot pressure generating device and structured to supply hydraulic oil to the hydraulic control devices via pilot lines. In the illustrated example, the pilot pump 15 is a fixed displacement hydraulic pump. However, the pilot pressure generating device may be implemented by the main pump 14 as well. That is, in addition to the function to supply hydraulic oil to the control valve unit 17 via a hydraulic oil line, the main pump 14 may also have a function to supply hydraulic oil to various hydraulic control devices via pilot lines. In this case, the pilot pump 15 may be omitted.

The discharge pressure sensor 28 is structured to detect the discharge pressure of the main pump 14. In the example shown in the figure, the discharge pressure sensor 28 outputs the values detected thereby to the controller 30.

The operator controls the actuators using operating devices 26. The operating devices 26 include, for example, operating levers, operating pedals, and so forth. The actuators may be hydraulic actuators or electric actuators.

An operation sensor 29 is structured to detect the details of maneuvers the operator performs on the operating devices 26. In this embodiment, for example, the operation sensor 29 detects the directions and amounts of maneuvers performed on the operating devices 26 in association with respective actuators, and outputs the detected values to the controller 30. In the illustrated example, for example, the controller 30 can control the opening area of a proportional valve 31 in accordance with outputs from the operation sensor 29. The controller 30 then supplies the hydraulic oil discharged from the pilot pump 15, to the pilot ports of corresponding control valves in the control valve unit 17. The pressure (pilot pressure) of hydraulic oil supplied to each pilot port depends, in principle, on the directions and amounts of maneuvers performed on the operating devices 26 in association with corresponding hydraulic actuators. In this way, the operating devices 26 are structured to supply the hydraulic oil discharged from the pilot pump 15 to the pilot ports of control valves in the control valve unit 17.

The proportional valve 31 functions as a control valve in machine control and is located on a pipeline connecting the pilot pump 15 and the control valves' pilot ports in the control valve unit 17. The proportional valve 31 is structured such that the pipeline's flow path area can be adjusted. In the illustrated example, the proportional valve 31 works in accordance with control commands output from the controller 30. Therefore, the controller 30 can adjust the pilot pressure that acts on the pilot port of each control valve by using the proportional valve 31, regardless of what maneuvers the operator performs on the operating devices 26.

Structured thus, the controller 30 can, for example, run a hydraulic actuator that is associated with a specific operating device 26 even when that specific operating device 26 is not maneuvered.

Furthermore, as shown in FIG. 3, the control system of the work machine 100 includes a controller 30, a secondary storage device ST, a display device D1, an input device D2, a communication device T1, etc.

The display device D1 is situated in a location that the operator seated in the operation room 10 can see with ease, and, under the control of the controller 30, displays images representing various information. In the illustrated example, the display device D1 is located to the front right of the operator's seat, and connected to the controller 30 via a dedicated line. The display device D1 displays various pieces of image information. The display device D1 includes a display screen that displays information such as the job conditions and the status of operation of the work machine 100. The operator seated in the operator's seat can perform jobs using the work machine 100 while checking the variety of information displayed on the display device D1. The input device D2 may be provided in the display device D1.

The input device D2 is located within reach of the operator seated in the operator's seat. Various maneuvers are performed and received as inputs by the input device D2, and signals corresponding to or matching the maneuvers are output to the controller 30. The input device D2 includes at least: a touch panel, which is mounted on the display of the display device D1 and displays images representing various information; a knob switch, which is mounted on the tip of one or more of multiple operating levers included in the operating device 26; and a button switch, a lever, a toggle switch, a rotary dial, and so forth, which are mounted around the display device D1. Signals corresponding to the details of maneuvers performed on the input device D2 are input to the controller 30.

The controller 30 is structured to output control commands to the regulator 13 when necessary, and change the amount of discharge from the main pump 14.

The controller 30 may also be structured to control the machine guidance function to guide the operator in maneuvering the work machine 100 manually via the operating devices 26. The controller 30 may also be structured to control the machine control function to automatically assist the operator in maneuvering the work machine 100 manually via the operating devices 26.

Note that some of the functions of the controller 30 may be implemented through other controllers (control devices). In other words, the functions of the controller 30 may be implemented in a distributed manner spanning multiple controllers. For example, the machine guidance function and the machine control function may be implemented by respective dedicated controllers (control devices).

The secondary storage device ST is a readable, writable, and non-volatile storage medium.

[Explanation of Load on Work Machine]

The work machine 100 is used under a variety of circumstances depending on, for example, the place where a job takes place, the details of the job, and so forth. Consequently, when the work machine 100 performs a job, a case might occur in which a part of the work machine 100 is subject to load greater than expected and gets damaged quickly.

FIG. 4 is a diagram illustrating loads produced in varying parts of the work machine 100 according to this embodiment. The example shown in FIG. 4 illustrates a case in which, when the boom 4 is lowered, a strong impact 1402 acts on the toe of the bucket 6 because the boom 4 moves fast and the stones and other objects contained under the ground 1401 are hard.

In this case, the toe of the bucket 6 is not the only place where load is produced; varying loads are produced in different parts of the work machine 100. For example, the load that a predetermined part 1411 in a lower plate (i.e. flat part) of the arm 5 experiences, the load that a predetermined part 1412 near the center of a lower plate of the boom 4 experiences, and the load that a predetermined part 1413 near the base of the boom 4 experiences all vary.

Structured thus, the work machine 100 has parts that are resistant to load and parts that are vulnerable to load. Parts that are vulnerable to load include, but are not limited to, welding parts in plates constituting at least part of the attachment AT of the work machine 100, and parts nearby.

The controller of this embodiment is therefore structured to calculate the stress or load produced in each part constituting at least part of the attachment AT of the work machine 100, and issue a notice if there is a part where the stress or load occurring there is greater than or equal to a pre-configured value.

To be more specific, various sensors provided in the work machine 100 of this embodiment acquire information about the stress or load on the work machine 100. For example, the controller 30 calculates the stress produced in a predetermined part of the work machine 100 based on the information acquired by the sensors, and issues a notice if the stress the predetermined part is experiencing is greater than a predetermined value.

<Block Structure of Work Machine's Controller>

The functional elements of the controller 30 and the secondary storage device ST of the work machine 100 of this embodiment will be described below with reference to FIG. 3. The controller 30 (an example of a control part) of this embodiment is structured to control the entire work machine 100. The functional blocks shown in the controller 30 are conceptual representations and do not necessarily have to be formed in the physical structure shown in the figure. Part or all of the functional blocks can be physically or functionally separate, or integrated together in a desired unit. Part or all of the processes and functions performed by each functional block are implemented by executing programs on a CPU. Alternatively, the functional blocks may be implemented using hardware incorporating wired logic. The controller 30 includes an acquiring part 301, a determining part 302, a notifying part 303, a saving part 304, and an evaluation part 305, which are implemented by executing programs. Furthermore, the secondary storage device ST has a cumulative value storage part ST1.

In the cumulative value storage part ST1, for example, a predetermined part and the cumulative damage level value in the predetermined part are associated with each other and stored. The cumulative damage level value in a predetermined part is the value obtained by adding up the damage levels having occurred there up until then. In the event the cumulative damage level value in a predetermined part increases, the controller 30 then assumes that chances are high that the predetermined part will suffer damage. Specific examples of damage levels will be described later.

The cumulative value storage part ST1 of this embodiment thus stores cumulative damage level values calculated per predetermined part of the work machine 100. The controller 30 can issue notices based on these cumulative values. By issuing notices this way, for example, the work machine 100 can be inspected before anomalies arise due to metal fatigue or other factors, thereby improving the safety of the work machine 100.

Next, the structure of the controller 30 will be described. The acquiring part 301 acquires signals from various detection devices provided in the work machine 100. For example, the acquiring part 301 acquires position information, which indicates the results of measuring the position, orientation, etc. of the work machine 100, from the positioning device PS. The acquiring part 301 acquires image information from the image capturing devices S6.

In addition, the acquiring part 301 acquires cylinder pressures from the cylinder pressure sensors S7R, S7B, S8R, S8B, S9R, and S9B. These cylinder pressures are an example of information about stress or load occurring with respect to the work machine 100, acquired from various detection devices. Furthermore, according to this embodiment, cylinder pressures acquired from the cylinder pressure sensors S7R, S7B, S8R, S8B, S9R, and S9B are by no means the only information about stress or load occurring with respect to the work machine 100, and any information wherefrom the stress or load occurring in a predetermined part of the work machine 100 can be calculated may be used. For example, in the event a strain gauge or the like is provided in the attachment AT of the work machine 100, the acquiring part 301 may acquire information that indicates the stress or load occurring in the part where the strain gauge is provided as information for calculating the stress or load occurring in a predetermined part of the work machine 100. The acquiring part 301 may also acquire detection results obtained by an acceleration sensor provided in the attachment AT of the work machine 100 as information for calculating the stress or load occurring in a predetermined part of the work machine 100. Furthermore, the acquiring part 301 may acquire movies taken by the image capturing devices S6, sound signals collected by a sound collecting device, and so forth, as information for calculating the stress or load occurring in a predetermined part of the work machine 100.

The acquiring part 301 then calculates the stress produced in each of multiple predetermined parts of the work machine 100 based on detection results obtained from the detection devices including the cylinder pressure sensors S7R, S7B, S8R, S8B, S9R, and S9B. Any method may be used for the calculation of stress. For example, a predetermined algorithm that takes into account: cylinder pressures detected by the cylinder pressure sensors S7R, S7B, S8R, S8B, S9R, and S9B; and the structure of the work machine 100, may be used. Furthermore, the acquiring part 301 may determine the stress in each predetermined part by using machine learning. For example, the acquiring part 301 may input detection results obtained by detection devices in a trained model and determine the stress produced in each of multiple predetermined parts from the trained model. The trained model may be, for example, a machine learning model built on training data that combines detection results obtained by various detection devices and the stresses occurring in multiple predetermined parts together.

Furthermore, the acquiring part 301 may determine, for example, the stress occurring in a predetermined part of the work machine 100 based on at least one of: an acceleration measured by an acceleration sensor; a movie taken by an image capturing device S6 and showing the work machine 100 move; and the sound produced when the work machine 100 comes into contact with an object, collected by a sound collecting device (not shown), and so forth. For example, by inputting at least one of these acceleration, movie, and sound in a trained model, the acquiring part 301 determines the stress occurring in every predetermined part in the work machine 100.

Which “predetermined parts” are subject to the calculation of stress is determined by, for example, the business or the operator that owns the work machine 100. For example, at least one predetermined part among: a part where the worker wants to check the damage level; a part that is likely to be damaged in the work machine 100; a part that is likely to experience structural load; and a part that has been damaged in the past, is determined as being subject to monitoring. A welding part in the attachment AT of the work machine 100 and parts nearby are examples of predetermined parts.

To be more specific, examples of welding parts in the boom 4 and arm 5 of the attachment AT and parts nearby include, but are not limited to, the following: a part in a side plate welded with an upper/lower plate, and parts nearby; a part in an upper plate welded with a lower plate, and parts nearby; a part in an upper/lower plate where a rolled plate is welded, and parts nearby; a part where a side plate and a rolled plate are welded together, and parts nearby; a part in a side plate where a boss is welded, and parts nearby; a part in an upper/lower plate where a boss is welded, and parts nearby; a part in a side plate welded with a partitioning member, and parts nearby; a part in an upper/lower plate welded with a rolled plate, and parts nearby; a part in an upper/lower plate welded with a partitioning member, and parts nearby; and a part in an upper/lower plate where a bracket is welded, and parts nearby. Note that these parts are only examples, and other parts may be made subject to the calculation of stress as well.

The determining part 302 determines, for example, whether the stress produced in a predetermined part of the work machine 100 is greater than a predetermined value. According to this embodiment, the predetermined value is determined depending on various factors related to the work machine 100, including, but not limited to, the structure and materials of the work machine 100. The predetermined value may be determined per predetermined part subject to the calculation of stress, or a common value may be used for multiple predetermined parts.

Based on the result obtained in the determining part 302, the notifying part 303 issues a notice to at least one of: the display device D1 (an example of an output device), which is for use by the operator who maneuvers the work machine 100; the mobile communication terminal 500 (an example of a first information processor), which the worker who performs maintenance work for the work machine 100 carries with him/her; and the management device 700 (an example of a second information processor), which is for use by the managing person who manages the work machine 100. When issuing a notice to the mobile communication terminal 500 or the management device 700, the notifying part 303 uses the communication device T1. With this embodiment, a notice is issued to at least one of the display device D1, the mobile communication terminal 500, and the management device 700. This allows people at work around or in relationship to the work machine 100 to learn the circumstances with respect to the load (stress) the work machine 100 is experiencing. Consequently, for example, maintenance for the work machine 100 can be performed before damage occurs due to load, thereby improving the safety of the work machine 100.

In this embodiment, an example in which a notice is issued to the operator using the display device D1 has been described. However, the present invention is by no means limited to techniques using the display device D1 when issuing a notice to the operator. For example, sound/voice may be output from a speaker (not shown) that is installed in the operation room 10, or a light source may be turned on to alert the operator.

According to this embodiment, when the notifying part 303 issue a notice to one or both of the mobile communication terminal 500 and the managing person's management device 700, a method of sending information such as a message containing that notice is used. However, the present invention is by no means limited to sending information such as messages, and different types of information such as visual information, audio information, and so forth may be sent when issuing a notice.

According to this embodiment, when the stress occurring in a predetermined part of the work machine 100 is determined to be greater than a predetermined value, the notifying part 303 issues a notice containing at least one of: information that indicates where in the work machine 100 the predetermined part is located; information that indicates the level of damage occurring in the predetermined part; and information that indicates the details of the job having made the stress or load on the predetermined part greater than the predetermined value. The notice issued thus allows the location where the stress is occurring and the situation in which the stress occurred to be known.

FIG. 5 is a graph for explaining predetermined values, based on which the determining part 302 according to this embodiment determines whether a certain amount of stress is produced. In the graph shown in FIG. 5, the vertical axis is stress and the horizontal axis is time.

In the example shown in FIG. 5, first predetermined values “Th1” and “−Th1,” which are positive and negative values respectively, and second predetermined values “Th2” and “−Th2,” are shown as thresholds for detecting stress.

In the example shown in FIG. 5, the first predetermined values Th1 and −Th1 and the second predetermined values Th2 and −Th2 are used to detect the negative stress and positive stress occurring in predetermined parts of the work machine 100.

The second predetermined values Th2 and −Th2 are applied to stress with greater absolute values than stress comparable to the first predetermined values Th1 and −Th1. When stress greater than the second predetermined values Th2 and −Th2 occurs, a notice needs to be issued to the operator of the work machine 100 to prevent or substantially prevent such stress from occurring again.

For example, if the determining part 302 determines that the absolute value of a peak stress value occurring in a predetermined part of the work machine 100 exceeds a second predetermined value |Th2|, the notifying part 303 issues a notice to the display device D1. When the notifying part 303 issues a notice to the display device D1 thus, the notice contains information indicating the details of the job having made the stress greater than the second predetermined value |Th2|. Examples of the details a job include, but are not limited to, the movement the work machine 100 makes during the job. Note that, according to this embodiment, the notice issued to the display device D1 is by no means limited to information that indicates the details of jobs. For example, the notifying part 303 may issue a notice containing at least one of: information that indicates where in the work machine 100 a predetermined part in which the stress is greater than the second predetermined value |Th2| is located; and information that indicates the level of damage occurring in that predetermined part.

Referring to the example shown in FIG. 5, if a stress peak value 1502 having an absolute value greater than the second predetermined value |Th2 | is calculated while the work machine 100 is engaged in moving the boom 4 downward for excavation, the notifying part 303 pops up a warning on the display device D1 urging the operator to reduce the speed the next time he/she moves the boom 4 downward.

The first predetermined values Th1 and −Th1 are thresholds determined based on, for example, the stress that a predetermined part of the work machine 100 can withstand, as predicted upon design of the work machine 100, and are set in order to predict damage to the predetermined part or to detect damage early. In other words, if stress greater than the first predetermined values Th1 and −Th1 occurs in a predetermined part of the work machine 100, the stress is more than the stress that the predetermined part can withstand; that is, the impact is greater than might occur upon intended usage of the work machine 100, and therefore a notice needs to be issued.

For example, if the determining part 302 determines that the absolute value of a peak stress value occurring in a predetermined part of the work machine 100 is greater than the first predetermined value |Th1|, the notifying part 303 issues a notice to one or both of the mobile communication terminal 500 and the management device 700.

To be more specific, if the stress occurring in a predetermined part of the work machine 100 yields peak stress values 1501, 1502, 1503, and 1504, in other words, if the determining part 302 determines that the absolute values of these peak stress values occurring in a predetermined part of the work machine 100 are greater than the first predetermined value |Th1|, the notifying part 303 issues a notice to one or more of the mobile communication terminal 500 and the management device 700. When the notifying part 303 issues the notice to one or more of the mobile communication terminal 500 and the management device 700, the notice contains: information that indicates where in the work machine 100 the predetermined part experiencing greater stress than the second predetermined value |Th1| is located; information that indicates the level of damage occurring in the predetermined part; and information that indicates the details of the job having made the stress greater than the first predetermined value |Th1|. Here, according to this embodiment, the information to be included in the notice issued to one or more of the mobile communication terminal 500 and the management device 700 is by no means limited to: information that indicates where in the work machine 100 the predetermined part is located; information that indicates the level of damage occurring in the predetermined part; and information that indicates the details of the job (for example, the movement of the work machine 100 during the job). At least one of these pieces of information, or other information, may be included in the notice.

The controller 30 according to this embodiment places different information in a notice depending on whether it is issued to the display device D1 (an example of an output device) or to the mobile communication terminal 500 or the management device 700. Furthermore, according to this embodiment, the information to be included in a notice need not be the same between the mobile communication terminal 500 and the management device 700. That is, a notice that is issued to the mobile communication terminal 500 and a notice that is issued to the management device 700 may contain different information. The controller 30 of this embodiment provides greater serviceability by presenting appropriate information depending on to which recipient a notice is issued.

The controller 30 according to this embodiment issues a notice when the stress produced in a predetermined part of the work machine 100 is greater than the absolute values of a predetermined negative value and a predetermined positive value. In other words, according to this embodiment, a notice is issued regardless of whether the stress produced in a predetermined part of the work machine 100 is tensile stress or compressive stress. Consequently, any unexpected stress occurring in a predetermined part can be detected reliably, leading to improved safety.

Note that although this embodiment has illustrated examples in which certain information is included in a notice when issued by the controller 30, the types of information in the above description are only examples and the present invention is by no means limited to these. For example, the notifying part 303 may be structured such that, when issuing a notice to the display device D1 and (1) information that identifies a predetermined part in the work machine 100 where stress or load greater than a predetermined value is occurring, (2) information that indicates the level of damage occurring in the predetermined part, and (3) information that indicates the job's details having made the stress or load on the predetermined part greater than the predetermined value, are available for inclusion in the notice, at least one of the information (1) to (3) is sent in the notice. Conversely, when a notice is issued to one or more of the mobile communication terminal 500 and the management device 700 and the information (1) to (3) are available, more information may be selected from the information (1) to (3) and sent in the notice than when a notice is issued to the display device D1.

In this way, when a notice is issued to one or more of the mobile communication terminal 500 and the management device 700, the notice contains more information than does a notice issued to the display device D1. In other words, according to this embodiment, considering that the operator is engaged in maneuvering of the work machine 100, the information to be sent in the notice is narrowed down and presented to the operator such that the operator is not distracted and led to maneuvering the work machine 100 in a potentially damaging way. Furthermore, more (i.e. a greater amount of) information is presented to at least one of the managing person and the worker so that at least one of them can be updated with the current damage level of the work machine 100. By issuing these notices, according to this embodiment, the level of damage to the work machine 100 due to the operator's maneuvering can be reduced, and, furthermore, at least one of the managing person and the worker can be updated with the current damage level of the work machine 100. This allows maintenance and services to be performed for the work machine 100 based on its current damage level, thus improving the safety of the work machine 100.

Despite the foregoing, this embodiment is by no means limited to an example in which a notice is issued when the absolute value of a peak stress value occurring in a predetermined part of the work machine 100 exceeds a predetermined value. For example, the determining part 302 identifies the job being performed by the work machine 100 based on at least one of: detection results obtained by the angle sensors S1, S2, and S3; detection results obtained by the rotation sensor S5; the stress produced in a predetermined part of the work machine 100; and images taken by the image capturing devices S6, and issues a notice if the work machine 100 is performing a predetermined job. An example of the predetermined job is “brooming,” in which the bucket 6 moves sideways to move an object such as a clay pipe. In other words, the controller 30 issues a notice when a job (movement) that the work machine 100 is not supposed to perform is detected. The recipient of the notice has only to be one or more among the display device D1, the mobile communication terminal 500, and the management device 700.

In the example shown in FIG. 5, the controller 30 issues a notice when the stress occurring in a predetermined part of the work machine 100 has a peak value greater than one of the predetermined values. However, this embodiment is by no means limited to an example in which a notice is issued when the stress occurring in a predetermined part of the work machine 100 shows a peak value that is greater than a predetermined value. The controller 30 according to this embodiment also issues a notice when a cumulative damage level value determined based on the stress occurring in a predetermined part of the work machine 100 is greater than a predetermined threshold.

When the determining part 302 determines that the value of a peak stress value occurring in a predetermined part of the work machine 100 is greater than the first predetermined value |Th1|, the saving part 304 calculates the level of damage based on the stress occurring in the predetermined part, and saves the cumulative damage level value in the predetermined part in the cumulative value storage part ST1. Next, “the damage level in a predetermined part of the work machine 100” according to this embodiment will be described.

According to this embodiment, when stress is produced in a predetermined part of the work machine 100, it is either tensile stress (i.e. stress in the positive direction) or compressive stress (i.e. stress in the negative direction).

For example, referring again to the example shown in FIG. 5, the peak value 1501 of tensile stress in a predetermined part of the work machine 100 occurs in the period 1511. Furthermore, the peak value 1504 of tensile stress in the predetermined part occurs in the period 1513.

Conversely, the peak value 1502 of tensile stress in the predetermined part occurring in the period 1512 is followed by the peak value 1503 of compressive stress.

Thus, when tensile stress is produced in a predetermined part of the work machine 100, followed by compressive stress, the degree of metal fatigue is greater (that is, the damage level in the predetermined part is greater) than when tensile stress alone or compressive stress alone is produced in the predetermined part.

Therefore, the controller 30 according to this embodiment calculates the damage level in a predetermined part of the work machine 100 based on stress amplitude. Stress amplitude is defined as half the difference between the maximum stress and the minimum stress in a predetermined period of time. For example, halving the difference 1521 between the maximum stress and the minimum stress gives the stress amplitude for the period 1511. Likewise, halving the difference 1522 between the maximum stress and the minimum stress is the stress amplitude for the period 1512, and halving the difference 1523 between the maximum stress and the minimum stress is the stress amplitude for the period 1513.

There is a relationship between a stress amplitude ow and the number of times (“N”) the stress amplitude ow occurs before a fracture (damage) occurs in a predetermined part of the work machine 100. FIG. 6 shows an example relationship between the stress amplitude ow and the number of times N the stress amplitude ow occurs before a fracture (damage) occurs in a predetermined part of the work machine 100. The vertical axis is the logarithm (log σw) of stress amplitude, and the horizontal axis is the logarithm (log N) of the number of times a stress amplitude occurs before a fracture (damage) occurs in a predetermined part of the work machine 100.

Furthermore, as shown by the line labeled “1601” in FIG. 6, there is a relationship between the logarithm (log OW) of stress amplitude in a predetermined part and the logarithm (log N) of the number of times a stress amplitude occurs before a predetermined part is damaged. In the example shown in FIG. 6, σW₁>σw₂>σw₃ and N₁<N₂<N₃ hold true.

Referring to FIG. 6, if a stress amplitude σw₁ occurs N₁ times, if a stress amplitude σw₂ occurs N₂ times, or if a stress amplitude σw₃ occurs N₃ times, there is a high possibility that a predetermined part will suffer damage. In other words, the stress amplitude σw₁ is associated with a damage level (damage) of 1/N₁ until a predetermined part of the work machine 100 is damaged. The stress amplitude σw₂ is associated with a damage level (damage) of 1/N₂ until the predetermined part is damaged. The stress amplitude σw₃ is associated with a damage level (damage) of 1/N₃ until the predetermined part is damaged.

For each metal material, the stress amplitude ow and the number of times N the stress amplitude ow occurs before a fracture occurs in a predetermined part of the work machine 100 can be expressed using mathematical expressions. The following mathematical expression 1 is an equation that shows the relationship between the stress amplitude ow and the number of times N the stress amplitude ow occurs before a fracture occurs. m and C are material constants for the metal used in the predetermined part.

σ ⁢ w m · N = C m ( 1 )

According to this embodiment, the damage level is: D=1/N. In other words, when the cumulative value of damage levels D reaches “1,” the controller 30 can determine that a fracture (damage) is likely to occur in a predetermined part of the work machine 100. The saving part 304 calculates the damage level D using the following mathematical expression 2.

D = 1 / N = ( σ ⁢ w / C ) m ( 2 )

In the event the absolute value of a peak stress value occurring in a predetermined part of the network machine 100 exceeds the first predetermined value |Th1|, the saving part 304 of this embodiment calculates the damage level D in that predetermined part from the stress amplitude in the predetermined period in which the stress occurred (and which lasts 3 seconds, for example), adds this damage level D to the cumulative damage level value for the predetermined part stored in the cumulative value storage part ST1, and saves the resulting cumulative value in the cumulative value storage part ST1.

In the event stress is produced in a predetermined part and the absolute value of its peak value exceeds the first predetermined value |Th1|, the saving part 304 of this embodiment may store a movie taken by an image capturing device S6 and audio information collected by a sound collecting device (not shown) and capturing a predetermined period (lasting 3 seconds, for example) including the point where the first predetermined value |Th1| is exceeded, in the secondary storage device ST, as the status of job when the stress occurred.

When the saving part 304 thus updates a value stored in the cumulative value storage part ST1, the notifying part 303 may send, to one or both of the mobile communication terminal 500 and the managing person's management device 700, a message stating that the current damage level in the predetermined part of the work machine 100 is approximately X (X being a value on a scale of 0 to 1).

The determining part 302 makes decisions based on the cumulative damage level value in the predetermined part. FIG. 7 is a graph for explaining how the determining part 302 of this embodiment makes decisions based on the cumulative damage level value in a predetermined part of the work machine 100. The vertical axis is the cumulative damage level value, and the horizontal axis is time.

In the example shown in FIG. 7, as shown by the line labeled “1701,” the cumulative damage level value in a predetermined part of the work machine 100 increases over time.

According to this embodiment, two thresholds are provided for evaluating the cumulative damage level value in a predetermined part of the work machine 100. For example, a warning threshold Th11 is defined to send a notice stating that damage has been accumulating, to at least one of the operator, the managing person, and the worker. The warning threshold Th11 is, for example, 0.6. A replacement threshold Th12 is defined to recommend replacing a predetermined part when a fracture (damage) is likely to occur in the predetermined part. The replacement threshold Th12 is, for example, 0.8.

For example, if the determining part 302 determines that the cumulative damage level value in a predetermined part of the work machine 100 is greater than the warning threshold Th11, the notifying part 303 displays a message on the display device D1 stating that damage has been accumulating and that the work machine 100 needs to be maneuvered with care. The message is displayed, for example, when the work machine 100 completes a job.

In the event the determining part 302 determines that the cumulative damage level value in a predetermined part of the work machine 100 is greater than the warning threshold Th11, the notifying part 303 may send information indicating that damage has been accumulating to one or both of the mobile communication terminal 500 and the managing person's management device 700.

For example, if the determining part 302 determines that the cumulative damage level value in a predetermined part of the work machine 100 is greater than the replacement threshold Th12, the notifying part 303 displays a message, on the display device D1, stating that an engineer is needed and that the work machine 100 requires a detailed inspection. This message may be displayed, for example, when the work machine 100 finishes a job, or at the timing the cumulative damage level value in a predetermined part of the work machine 100 becomes greater than the replacement threshold Th12.

Furthermore, if the determining part 302 determines that the cumulative damage level value in the predetermined part is greater than the replacement threshold Th12, the notifying part 303 sends a message recommending replacement of a component/components associated with the predetermined part, to one or both of the mobile communication terminal 500 and the managing person's management device 700. Thus, even if damage occurs in a predetermined part of the work machine 100, the worker and the managing person can prepare for replacement of a component/components associated with the predetermined part.

Thus, according to this embodiment, the notifying part 303 issues a notice when a peak stress value that is greater than a predetermined value occurs in a predetermined part of the work machine 100, or when the cumulative damage level value (example of a stress-based cumulative value) in a predetermined part of the work machine 100 becomes greater than a warning threshold Th11 or a replacement threshold Th12. Although an example is described with this embodiment in which the notifying part 303 issues a notice based on a peak stress value occurring in a predetermined part of the work machine 100 or issues a notice based on the cumulative damage level value (example of a stress-based cumulative value) in a predetermined part of the work machine 100, the issuance of notices according to this embodiment is by no means limited to this example. For example, between the above two types of notices, the notifying part 303 may issue only the notice based on the peak stress value in a predetermined part of the work machine 100, or issue only the notice based on the cumulative damage level value (example of a stress-based cumulative value) in a predetermined part of the work machine 100. The notifying part 303 may furthermore issue a notice based on an average value of stress occurring in a predetermined part of the work machine 100. In addition, this embodiment is by no means limited to issuing notices based on stress, and may issue notices based on load (for example, based on at least one of a peak load value and a load-based cumulative value). For example, the notifying part 303 may issue a notice based on: the load applied to the toe of the attachment AT during excavation; the rotational force applied to the entire attachment AT when thee attachment AT starts or stops rotating; the weight of the entire attachment AT when the attachment AT is lifted upward; and the load applied to the bucket 6 when lifting the load or the content of the bucket 6.

Furthermore, a technique may be available for this embodiment whereby, when the absolute value of a peak stress value occurring in a predetermined part of the work machine 100 exceeds the first predetermined value |Th1|, the notifying part 303 issues a notice indicating the number of times the peak stress value exceeds the first predetermined value |Th1| during a predetermined period (which lasts, for example, 3 seconds), identifying the points at which the peak stress value exceeds the first predetermined value |Th1|.

In the example shown in FIG. 5, when the peak value 1501 or the peak value 1504 is detected, the notifying part 303 sends, in a notice, the number of times the peak value 1501 or the peak value 1504 exceeds the first predetermined value |Th1| (i.e., one time in the figure). Furthermore, in the event the peak value 1502 is detected, since the peak value 1502 and the peak value 1503 are also observed in the same predetermined period, the notifying part 303 sends, in a notice, the number of times these peak values 1502 and 1503 exceed the first predetermined value |Th1| (i.e., twice in the figure). In addition to this technique of reporting the number of times a given peak value exceeds the first predetermined value |Th1|, the notifying part 303 of this embodiment can also send, for example, a peak stress value or a stress amplitude determined from the maximum stress and the minimum stress in a predetermined period, in a notice. At least one of the mobile communication terminal 500 and the managing person's management device 700 is the recipient. If a peak stress value is detected to exceed a predetermined value a predetermined number of times or more, the display device D1 may be added as another recipient. The predetermined period need not be 3 seconds long. The duration of the predetermined period has only to be determined depending on the embodiment and may last, for example, from when the engine 11 of the work machine 100 is started, until the engine 11 is stopped.

Returning to FIG. 3, the evaluation part 305 evaluates the operator's maneuvering skills of the work machine 100. For example, the evaluation part 305 calculates the score of the operator's maneuvering skills of the work machine 100 based on cumulative damage level values in multiple predetermined parts of the work machine 100 up until the engine 11 is stopped.

For example, the secondary storage device ST stores typical data of cumulative damage level values in multiple predetermined parts when the work machine 100 performs a job for an hour. When the engine 11 stops, the evaluation part 305 calculates hourly average values of cumulative damage level values per predetermined part. For example, the evaluation part 305 compares the average damage level values calculated thus, with typical data, to calculate the score of the operator's maneuvering skills of the work machine 100. Any method may be used to calculate the score, including existing methods.

Furthermore, the evaluation part 305 may compare the scores calculated thereby, with scores calculated nationwide, per operator who maneuvers the work machine 100, thus calculating a national ranking of operators. The operators subject to this comparison/ranking do not have to belong to a group of a national scale. Operators may be ranked within a job site where a particular operator belongs, or operators may be ranked within the business that owns the work machine 100. The notifying part 303 then displays, on the display device D1, one or both of the scores and the ranking of operators calculated by the evaluation part 305. Any method may be used to calculate the ranking. For example, the evaluation part 305 may obtain a cumulative damage level value for each operator managed via the management device 700, from the management device 700, and determine the ranking (ranks) of operators based on the cumulative values obtained on a per operator basis.

Next, the contents of notices displayed on the display device D1 will be described. According to this embodiment, the notifying part 303 displays, for example, the content of a notice on the display device D1 when the engine 11 of the work machine 100 is stopped.

FIG. 8 is a diagram illustrating an example of a display screen shown on the display device D1 by the notifying part 303 according to this embodiment. As shown in FIG. 8, an image display part 42 is turned on when the engine 11 of the work machine 100 is stopped.

The image display part 42 includes, for example, a date/time display field 42a, a travel mode display field 42b, an attachment display field 42c, a mileage display field 42d, an engine control status display field 42e, a coolant temperature display field 42g, a fuel level display field 42h, a rotation rate display field 42i, a diesel exhaust fluid level display field 42j, a hydraulic oil temperature display field 42k, an image display field 1801, and a notice display field 1802.

In the date/time display field 42a, an image showing the current date and time is displayed.

In the travel mode display field 42b, an image showing the current travel mode is displayed. In the attachment display field 42c, an image showing the attachment mounted at present is displayed. In the engine control status display field 42e, an image showing the control status of the engine 11 is displayed. In the rotation rate display field 42i, an image showing the level of the current rotation rate (e.g., revolutions per minute (rpm)) set by a dial is displayed. In the rotation rate display field 42i, a value/number indicating the currently selected level is displayed.

In the mileage display field 42d, an image showing mileage information calculated by the controller 30 is displayed. The mileage display field 42d includes, for example, an average mileage display field 42d1 for displaying an image showing the lifetime average mileage or the average mileage per period, and an instantaneous mileage display field 42d2 for displaying an image showing instantaneous mileage.

In the coolant temperature display field 42g, an image showing the engine coolant's current temperature is displayed. In the fuel level display field 42h, an image showing the remaining amount of fuel in the fuel tank is displayed. In the diesel exhaust fluid level display field 42j, an image showing the remaining amount of aqueous urea solution in the aqueous urea solution tank is displayed. In the hydraulic oil temperature display field 42k, an image showing the temperature of hydraulic oil in the hydraulic oil tank is displayed.

In the image display field 1801, images captured by the image capturing devices S6 before the engine 11 stopped are displayed.

The notice display field 1802 is a display field that pops up over the image display field 1801 when the engine 11 stops. For example, if the absolute value of a peak stress value produced in a predetermined part of the work machine 100 becomes greater than the second predetermined value |Th2| while the work machine 100 is performing a job, the notice display field 1802 displays information about the job's details having made the peak stress value greater than the second predetermined value |Th2 |. The example shown in FIG. 8 assumes that the absolute value of a peak stress value is greater than the second predetermined value |Th2| during rotating movement, so that the notifying part 303 displays, in the notice display field 1802, advice 1802B stating that attention needs to be paid not to come into contact with surrounding objects during rotating movement.

The notifying part 303 also displays a message 1802A reading “45/100” as the score of the operator's maneuvering skills of the work machine 100 in the notice display field 1802. The notifying part 303 also displays a message 1802C stating that the operator's rank at the job site is: “Job site ranking: 5th.”

In this way, the notifying part 303 ranks the operators who can maneuver the work machine 100 within the country, within the business, or within the job site, based on cumulative damage level values that are determined based on the stress produced in predetermined parts of the work machine 100 while the operator maneuvers the work machine 100, up until the engine 11 (which is an example of a drive source) is stopped, and sends the ranking in a notice at the timing the engine 11 is stopped. This embodiment by no means limits the content of the notice to the ranking. The content of the notice has only to relate to any form of evaluation of operators' maneuvering skills within the country, within the business, within the job site, and so forth. For example, the operator's rank or standard deviation score may be included in the notice. Any method may be used to obtain other operators' cumulative damage level values. For example, the controller 30 may obtain other operators' cumulative damage level values from the management device 700.

According to this embodiment, advice is displayed regarding the details of the job having made the stress occurring in a predetermined part greater than the second predetermined value |Th2 |. Following this, the operator maneuvers the work machine 100 taking this advice into account, thereby ensuring improved safety. This advice may be associated with the job's details and stored in the secondary storage device ST together. This enables the notifying part 303 to provide advice according to the details of jobs in a notice.

According to this embodiment, the operator's score, which is determined based on his/her maneuvering skills of the work machine 100, as well as the ranking of workers, are displayed. This allows the operator to compete with other workers for a higher score or a higher worker rank by maneuvering the work machine 100 such that predetermined parts of the work machine 100 do not experience excessive stress, thereby ensuring improved safety and durability of the work machine 100.

Although this embodiment has shown an example of a display screen that is displayed when the engine 11 is stopped, the present invention is by no means limited to this example display. Other pieces or types of information may be displayed on the display screen, such as the mileage while a job is in progress.

In addition, the notifying part 303 sends a notice to at least one of the mobile communication terminal 500 and the management device 700. This enables one or both of the mobile communication terminal 500 and the management device 700 to display the content of the notice.

FIG. 9 is a diagram illustrating an example in which a display screen is shown on the management device 700 based on information sent from the notifying part 303 of this embodiment. The display screen 1900 shown in FIG. 9 displays information about a job site A, which is managed by a managing person. For example, the first display field 1901 displays the name of the job site and the names of work machines used at the job site. In another example, the second display field 1902 displays an image taken by an image capturing device installed at the job site A.

If the absolute value of a peak stress value occurring in a predetermined part of a first work machine (an example of the work machine 100) is determined to be greater than the first predetermined value |Th1|, a notice display field 1911 pops up over the second display field 1902.

The notice display field 1911 displays the movement 1911A (job details) of the work machine 100, the part 1911B, the damage level 1911C, and the cumulative damage level 1911D.

The work machine's movement 1911A indicates the movement (job details) having caused the stress to exceed the first predetermined value |Th1|. For example, displaying “rotating movement” can help identify the movement that caused the excessive stress.

The part 1911B identifies the predetermined part where the stress exceeded the first predetermined value |Th1|. For example, when content to identify a part in a side of the arm welded with an upper/lower plate and parts nearby is indicated, the operator can learn that damage is likely to occur in this predetermined part.

The damage level 1911C displays the damage level in the predetermined part.

The damage level refers to information that indicates the magnitude of damage such that the managing person can comprehend the magnitude of damage (damage). The damage level is expressed, for example, on a scale of 1 to 5. For example, stress amplitudes and damage levels may be associated with each other and set in advance, so that, when a stress amplitude occurs in a predetermined part of the work machine 100, the damage level 1911C displays the damage level that corresponds to the stress amplitude.

The cumulative damage level 1911D displays the cumulative damage level value in the predetermined part as a percentage. For example, if the cumulative damage level value in the predetermined part is 0.65, “65/100” is displayed.

According to this embodiment, the management device 700 displays the display screen 1900, allowing the managing person to learn information about the stress occurring in a predetermined part of the work machine 100. By identifying the specific circumstances of the work machine 100 and, for example, adjusting the maintenance plan for the work machine 100 based thereon, improved safety of the work machine 100 can be ensured.

The information to be displayed on the management device 700 is by no means limited to the display screen shown in FIG. 9. The management device 700 may display, for example, the ranking of operators at the job site A (which is an example of a group). The managing person can decide whether each operator maneuvers the work machine 100 carefully. Therefore, the managing person can assign the work machine 100 to an operator based on whether the operator maneuvers the work machine 100 carefully. For example, a work machine 100 with a low cumulative damage level value may be assigned to an operator whose maneuvering of the work machine 100 is rough and a work machines 100 with a high cumulative damage level value may be assigned to an operator whose maneuvering of the work machine 100 is careful, thereby preventing or substantially preventing the work machines 100 from being damaged.

Furthermore, although an example in which the display screen 1900 of FIG. 9 is displayed on the management device 700 has been described, the display screen 1900 of FIG. 9 is not limited to being displayed on the management device 700, and may be displayed on the mobile communication terminal 500. This allows the worker to learn information about the stress occurring in predetermined parts of the work machine 100.

As described above, the notifying part 303 of this embodiment issues a notice at the timing the stress occurring in a predetermined part of the work machine 100 is determined to be greater than a predetermined value, and issues a notice at the timing the work machine 100 stops its engine 11. The timings to issue notices are by no means limited to the ones described with this embodiment. For example, a notice may be issued at the timing the stress occurring in a predetermined part of the work machine 100 is determined to be greater than a predetermined value, a notice may be issued at the timing the work machine 100 stops its engine 11, and so forth. This embodiment is structured to issue a notice at the timing the stress occurring in a predetermined part of the work machine 100 is determined to be greater than a predetermined value, so that the current situation of the work machine 100 can be learned. This makes it possible to take appropriate action depending on the current situation of the work machine 100, thereby ensuring improved safety. Furthermore, by issuing a notice at the timing the work machine 100 stops the engine 11, the operator can view the content of the notice without discontinuing the ongoing job. This prevents or substantially prevents a decrease in job efficiency.

Next, the flow in which the work machine 100 of this embodiment issues a notice will be described. FIG. 10 is a flowchart showing the flow in which the work machine 100 of this embodiment issues a notice.

First, the acquiring part 301 acquires information about the stress on the work machine 100 from the cylinder pressure sensors S7R, S7B, S8R, S8B, S9R, and S9B (S2001).

According to this embodiment, the acquiring part 301 calculates the stress occurring in a predetermined part A of the work machine 100 (S2002A). The determining part 302 then determines whether the absolute value of a peak stress value in the predetermined part A is greater than a first predetermined value (S2002A). If the determining part 302 determines that the absolute value of a peak stress value in the predetermined part A is less than or equal to the first predetermined value (“NO” in S2002A), the process of S2001 is repeated. On the other hand, if the determining part 302 determines that the absolute value of a peak stress value in the predetermined part A is greater than the first predetermined value (“YES” in S2002A), the process of S2004 is performed.

The acquiring part 301 calculates the stress occurring in a predetermined part B of the work machine 100 (S2002B). The determining part 302 then determines whether the absolute value of a peak stress value in the predetermined part B is greater than the first predetermined value (S2002B). If the determining part 302 determines that the absolute value of a peak stress value in the predetermined part B is less than or equal to the first predetermined value (“NO” in S2002B), the process of S2001 is repeated. On the other hand, if the determining part 302 determines that the absolute value of a peak stress value in the predetermined part B is greater than the first predetermined value (“YES” in S2002B), the process of S2004 is performed.

The acquiring part 301 performs the same process on every predetermined part included in the work machine 100 and being subject to monitoring, as it did on the predetermined part A and the predetermined part B. In other words, the acquiring part 301 calculates the stress occurring in each predetermined part in the work machine 100 being subject to monitoring, and, based on the stresses on the work machine 100 calculated thus, the determining part 302 determines whether there is a peak stress value having an absolute value greater than the first predetermined value.

If the determining part 302 determines that peak stress values pertaining to one or more predetermined parts of the work machine 100 being subject to monitoring, including the predetermined part A and the predetermined part B, have absolute values greater than the first predetermined value (“YES” in S2002A, “YES” in S2002B, etc.), the notifying part 303 sends a notice to (at least one of) the management device 700 and the mobile communication terminal 500 (S2004).

Then, for each predetermined part where a peak stress value is determined to have an absolute value that is greater than the first predetermined value, the saving part 304 calculates the damage level D in that predetermined part from the stress amplitude during the time period in which the stress occurred, and saves the cumulative value of damage levels D in the cumulative value storage part ST1 (S2005).

Furthermore, the determining part 302 determines whether, according to the calculations of S2002A, S2002B, etc., a peak stress value with an absolute value greater than a second predetermined value (>first predetermined value) is found in any of the predetermined parts of the work machine 100 being subject to monitoring, including the predetermined part A and the predetermined part B (S2006).

If the determining part 302 determines that a peak stress value with an absolute value greater than the second predetermined value (>first predetermined value) is not found in any of the predetermined parts (“NO” in S2006), the process moves on to S2008.

On the other hand, if the determining part 302 determines that there is a predetermined part where a peak stress value has an absolute value greater than the second predetermined value (>first predetermined value) (“YES” in S2006), the notifying part 303 displays a pop-up warning (example of a notice) on the display device D1 to tell the operator to moderate the ongoing operation (S2007).

Then, the controller 30 determines whether an operation to stop the engine 11 has been entered (S2008). If the controller determines that that an operation to stop the engine 11 has not been entered (“NO” in S2008), the process resumes from S2001.

On the other hand, if the controller 30 determines that an operation to stop the engine 11 has been entered (“YES” in S2008), the notifying part 303 displays a notice on the display device D1, including a score calculated by the evaluation part 305 (S2009). FIG. 8 shows the display screen displayed based on this notice.

An example has been described above with this embodiment in which a notice is issued based on the stress occurring in a predetermined part of the work machine 100. However, this embodiment is by no means limited to examples in which a notice is issued based on the stress occurring in a predetermined part of the work machine 100, and, for example, an example in which a notice is issued based on the load occurring in a predetermined part of the work machine 100 is likewise applicable. The same or substantially the same processes and steps as those described above may be performed in examples in which a notice is issued based on the load occurring in a predetermined part of the work machine 100, and so their description will not be repeated below.

Second Embodiment

A case will be described below as a second embodiment in which the operator remotely controls the work machine 100.

A sample structure of an operation system SYS (an example of a control system) according to the second embodiment will be described with reference to FIG. 11. FIG. 11 is a schematic diagram showing a sample structure of the operation system SYS according to the second embodiment. As shown in FIG. 11, the operation system SYS includes a work machine 100, a remote operation room RC, a management device 700, and a mobile communication terminal 500. FIG. 11 does not show the structures of the work machine 100, the management device 700, and the mobile communication terminal 500 in detail.

The work machine 100, the remote operation room RC, the management device 700, and the mobile communication terminal 500 are connected with each other so that they can send and receive data via the communication network NW. The work machine 100, the remote operation room RC, the management device 700, and the mobile communication terminal 500 may also be connected with each other so that they can send and receive data directly without involving the communication network NW. In the illustrated example, the work machine 100 sends information about the job site to the remote operation room RC. This allows the remote operator OP in the remote operation room RC to identify the situation at the job site based on the information from the work machine 100.

For example, the work machine 100 may send an image captured by an image capturing device S6 to the remote operation room RC.

The operation system SYS may include one work machine 100 or multiple work machines 100. When the operation system SYS includes multiple work machines 100, the remote operator OP of a given work machine 100 can obtain job site-related information that is available via that specific work machine 100, as well as job site-related information that is available via one or more other work machines 100.

The remote operation room RC is equipped with at least a communication device T2, a remote controller R40, an operating device R42, an operation sensor R43, and a display device DIE. The remote operation room RC is also equipped with an operator's seat DS to be occupied by the remote operator OP who maneuvers the work machine 100 from a remote location.

The communication device T2 can communicate with the communication device T1 attached to the work machine 100.

The remote controller R40 is a computing device that performs various calculations. According to this embodiment, the remote controller R40 is composed of a microcomputer including a CPU and a memory. The functions of the remote controller R40 are implemented when the CPU executes programs stored in the memory.

The display device DIE can display various information. The display device DIE displays images based on information transmitted from the work machine 100, so that the remote operator OP in the remote operation room RC can see the area around the work machine 100. In the illustrated example, the display device DIE is an LCD display for displaying images captured by the image capturing devices S6 mounted on the work machine 100. Note that the display device DIE may be a display or projector that provides naked-eye stereoscopic vision, VR goggles, etc.

An operation sensor R43 is installed on the operating device R42 to detect the details of maneuvers performed on the operating device R42. The operation sensor R43 may be, for example, an inclination sensor that detects the tilting angle of an operating lever, or an angle sensor that detects the swing angle of an operating lever about its swing axis. The operation sensor R43 may be other sensors as well, such as a pressure sensor, a current sensor, a voltage sensor, a distance sensor, and so forth. The operation sensor R43 outputs information that indicates the details of maneuvers performed on the operating device R42, to the remote controller R40. The remote controller R40 generates an operation signal based on the received information and sends the operation signal to the work machine 100. The operation signal may be generated by the operation sensor R43. In this case, the operation sensor R43 may output the operation signal to the communication device T2 without involving the remote controller R40. This structure allows the remote operator OP to maneuver the work machine 100 from the remote operation room RC.

The controller 30 according to this embodiment is structured the same or substantially the same as that of the first embodiment. The notifying part 303 of this embodiment issues a notice to the remote controller R40 instead of issuing it to the display device DIE. The remote controller R40 then displays the received notice on the display device D1E.

This embodiment is by no means limited to examples in which the controller 30 issue notices, and the remote controller R40 may be structured to issue notices. For example, the controller 30 may transmit signals from various detection devices provided in the work machine 100 to the remote controller R40, and the remote controller R40 may perform processes or steps that are the same or substantially the same as those performed by the controller 30 in the above-described first embodiment.

In the operation system of this embodiment, even when the remote operator OP maneuvers the work machine 100 from the remote operation room RC, notices are issued in the same manner as in the first embodiment described earlier, providing the same advantages as those of the first embodiment.

<Advantages>

According to the embodiments described above, the controller 30 is configured to issue a notice when a predetermined part of the work machine 100 experiences excessive load. The operator can then maneuver the work machine 100 such that excessive load will no longer be experienced. Furthermore, the managing person can share information with the operator and others to prevent excessive load from occurring. Furthermore, the worker can know which work machines 100 are experiencing excessive load and identify in which predetermined parts of these work machines 100 excessive load is produced. Therefore, the worker can schedule the maintenance plan for the work machine 100 in accordance with the circumstances of load occurring in the work machine 100, and identify parts of the work machine 100 that need to be inspected. Therefore, the embodiments described above can prevent the work machine 100 from getting damaged. Furthermore, by issuing notices as explained in the above description, the worker or the managing person can predict damage to the work machine 100 or detect damage to the work machine 100 from a remote location, at an early stage. Therefore, the downtime of the work machine 100 can be reduced.

Preferred embodiments variations of the present disclosure have been described above. However, the present invention according to the present disclosure is by no means limited to the above-described embodiments. Various modifications, substitutions, etc. may be applied to the above-described embodiments without departing from the scope of the present invention according to this disclosure. Furthermore, the features described above with reference to the embodiments may be combined as appropriate unless technical inconsistencies arise.