Work machine

Abstract

A control device of this work machine comprises: an inclination index calculation unit that calculates an inclination index of a traveling body vicinity area when the maximum difference in the axial direction of a revolving axis at each surface position of the traveling body vicinity areas becomes equal to or less than a predetermined first threshold value; an inclination index holding unit that holds a first inclination index which is an inclination index calculated by the inclination index calculation unit while a state in which the maximum difference is equal to or less than the first threshold value continues; and a vehicle body inclination variation determination unit that calculates a second inclination index which is an inclination index of the vehicle body, and provides a stabilization support device with an instruction for a support operation for securing stability of the vehicle body when the difference between the first inclination index held by the inclination index holding unit and the second inclination index of the vehicle body becomes equal to or more than a predetermined second threshold value.

Description

Work machinery

[0001] The present invention relates to a work machine such as a hydraulic excavator.

[0002] A hydraulic excavator, a typical example of a work machine, includes a lower traveling body, an upper rotating body that is rotatably attached to the lower traveling body and that, together with the lower traveling body, constitutes a vehicle body, and an articulated working device attached to the rotating body. The working device has a boom rotatably attached to the upper rotating body, an arm rotatably attached to the boom, and a bucket rotatably attached to the arm. Therefore, the posture and center of gravity of the work machine change depending on the orientation of the upper rotating body and the angle of the boom, etc.

[0003] Such work machines may be affected by the ground while traveling, which can reduce the stability of the vehicle body. Patent Document 1, for example, is a prior art document that discloses a technique for ensuring the stability of a work machine while traveling. Patent Document 1 discloses a technique that includes an imaging device and a distance sensor that acquire information about the surrounding ground, and a controller, and that determines the traveling stability when a shovel travels over the ground based on the information about the ground acquired by the imaging device and the distance sensor.

[0004] Japanese Patent Application Laid-Open No. 2021-155960

[0005] Patent Document 1 describes a method for assisting an operator by determining the level of danger when an excavator travels over ground based on image information about the area around the excavator and displaying the level of danger. However, it is difficult to accurately determine the level of danger from the appearance of the ground, and even on ground determined to be low in danger, if the ground is soft, for example, the weight of the work machine may cause the terrain to change while the excavator is traveling, reducing the stability of the vehicle body.

[0006] The present invention has been made in view of the above-mentioned problems, and its object is to provide a work machine that can ensure the stability of the vehicle body when traveling on terrain that appears to be drivable from the outside but where the stability of the vehicle body may be lost during traveling.

[0007] In order to achieve the above object, the present invention provides a work machine including a lower traveling body, an upper rotating body attached to the lower traveling body so as to be rotatable about a rotating axis and constituting a vehicle body together with the lower traveling body, a working device attached to the upper rotating body, an operation device for operating the lower traveling body, the upper rotating body and the working device, an attitude detection device for detecting the attitude of the vehicle body, a terrain information acquisition device for acquiring terrain information around the vehicle body, and a control device for controlling operations of the lower traveling body, the upper rotating body and the working device in accordance with operation of the operation device, the work machine including a stabilization assistance device that performs assistance operations to ensure the stability of the vehicle body, the control device including a ground area estimation unit that estimates a ground area from the terrain information acquired by the terrain information acquisition device, and a ground area estimation unit that estimates a front area from the ground area. The system has a vehicle vicinity area extraction unit that extracts a vehicle vicinity area including the area of ​​the lower vehicle and an area nearby it; a tilt index calculation unit that calculates a tilt index for the vehicle vicinity area when the maximum difference in the axial direction of the rotation axis of each surface position in the vehicle vicinity area becomes equal to or less than a predetermined first threshold; a tilt index holding unit that holds a first tilt index, which is the tilt index calculated by the tilt index calculation unit, while the maximum difference remains equal to or less than the first threshold; and a vehicle body tilt change determination unit that calculates a second tilt index, which is the tilt index of the vehicle body, from the attitude of the work machine detected by the attitude detection device, and instructs the stabilization assistance device to perform the assistance operation when the difference between the first tilt index held by the tilt index holding unit and the second tilt index of the vehicle body becomes equal to or greater than a predetermined second threshold.

[0008] According to the present invention, it is possible to ensure the stability of the vehicle body when the work machine travels on terrain that appears drivable from the outside but on which the stability of the vehicle body may be compromised during travel.

[0009] 1 is a diagram schematically illustrating the configuration of a hydraulic excavator. FIG. 1 is a diagram illustrating a configuration of a hydraulic system and a control system mounted on the hydraulic excavator. FIG. 2 is a functional block diagram of a control device according to a first embodiment. FIG. 3 is a side view showing a reference coordinate system together with the hydraulic excavator. FIG. 4 is a rear view showing the reference coordinate system together with the hydraulic excavator. FIG. 5 is a plan view showing the reference coordinate system together with the hydraulic excavator. FIG. 6 is a diagram illustrating the reference coordinate system and a grid map. FIG. 7 is a flowchart illustrating processing for extracting an area near a traveling object. FIG. 8 is a flowchart illustrating processing related to a stabilization support function. FIG. 9 is a side view of a hydraulic excavator in a case where a slope different from the slope expected in advance from the terrain occurs. FIG. 10 is a diagram illustrating an area near a traveling object including a slope surface. FIG. 11 is a diagram illustrating an example of operation of a notification device according to a first embodiment. FIG. 12 is a functional block diagram of a control device according to a second embodiment. FIG. 13 is a diagram illustrating movement of a hydraulic excavator according to a second embodiment. FIG. 14 is a diagram illustrating an example of operation of a notification device according to a second embodiment.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following, a hydraulic excavator equipped with a bucket as a working implement (attachment) at the tip of a working mechanism (front working mechanism) will be exemplified as a working machine. However, the present invention may also be applied to working machines equipped with attachments other than a bucket. Furthermore, the present invention may be applied to working machines other than hydraulic excavators, as long as they have an articulated working mechanism configured by connecting multiple front members (work implements, booms, arms, etc.) on a swiveling structure.

[0011] In the following description, when there are multiple identical components, a lowercase letter may be added to the end of the reference numeral, but the multiple components may be collectively referred to without the lowercase letter. For example, when there are three identical pumps 190a, 190b, and 190c, they may be collectively referred to as pump 190.

[0012] FIG. 1 is a diagram schematically illustrating the configuration of a hydraulic excavator 1.

[0013] The hydraulic excavator 1 performs the work of excavating a surface to be excavated, such as the ground (excavation work), and the work of loading the excavated material, such as soil and sand, onto a machine to be loaded, such as a transport machine including a dump truck 200 (shown in FIG. 17 ) (loading work). During this loading work, the hydraulic excavator 1 performs the action of transporting the excavated material to above the bed of the machine to be loaded (transporting action), and the action of discharging the excavated material onto the bed of the machine to be loaded (discharging action). The hydraulic excavator 1 is equipped with a multi-joint front working mechanism 2 that holds an object and rotates up and down or fore and aft, and a vehicle body 3 on which the front working mechanism 2 is mounted. The front working mechanism 2 is an example of a working mechanism equipped on a work machine.

[0014] The vehicle body 3 includes a lower traveling body 5 that travels using a right traveling hydraulic motor 4a and a left traveling hydraulic motor 4b, which are hydraulic actuators, and an upper rotating body 7 that is attached to the upper part of the lower traveling body 5 via a rotating device (not shown) and rotates using a swing hydraulic motor 6 (shown in FIG. 2), which is a hydraulic actuator provided on the rotating device. The lower traveling body 5 includes a left crawler 21a and a right crawler 21b that are paired on the left and right sides. In this embodiment, the left crawler 21a and the right crawler 21b are collectively referred to as crawlers 21.

[0015] The front working mechanism 2 is an articulated working mechanism made up of multiple front members attached to the front of the upper rotating structure 7. The front working mechanism 2 includes a boom 8 connected to the front of the upper rotating structure 7 so as to be rotatable in the vertical direction, an arm 9 connected to the tip of the boom 8 so as to be rotatable in the vertical direction, and a bucket 10 connected to the tip of the arm 9 so as to be rotatable in the vertical direction. A counterweight is provided at the rear of the upper rotating structure 7.

[0016] The boom 8 is connected to the upper rotating body 7 by a boom pin 8a (not shown) and rotates by the extension and contraction of a boom cylinder 11, which is a hydraulic actuator. The arm 9 is connected to the tip of the boom 8 by an arm pin 9a and rotates by the extension and contraction of an arm cylinder 12, which is a hydraulic actuator. The bucket 10 is connected to the tip of the arm 9 by a bucket pin 10a and a bucket link 16 and rotates by the extension and contraction of a bucket cylinder 13, which is a hydraulic actuator.

[0017] A boom angle sensor 14 is attached to the boom pin 8a, detecting the rotation angle of the boom 8 relative to the vehicle body 3 (upper rotating body 7). An arm angle sensor 15 is attached to the arm pin 9a, detecting the rotation angle of the arm 9 relative to the boom 8. A bucket angle sensor 17 is attached to the bucket link 16, detecting the rotation angle of the bucket 10 relative to the arm 9.

[0018] The method of acquiring the rotation angles of the boom 8, arm 9, and bucket 10 is not limited to the above-mentioned means, and the angles of the boom 8, arm 9, and bucket 10 relative to a reference plane such as a horizontal plane may be detected by an inertial measurement unit (IMU) and converted into rotation angles. The rotation angles of the boom 8, arm 9, and bucket 10 may also be acquired by detecting the strokes of the boom cylinder 11, arm cylinder 12, and bucket cylinder 13 with a stroke sensor and converting them into rotation angles.

[0019] An inclination angle sensor 18 is attached to the upper rotating body 7, which detects the inclination angle of the vehicle body 3 with respect to a reference plane such as a horizontal plane. A swing angle sensor 19 is attached to a swing device between the lower running body 5 and the upper rotating body 7, which detects the swing angle of the upper rotating body 7 with respect to the lower running body 5. The inclination angle of the lower running body 5 may be obtained by converting the value of the inclination angle sensor 18 attached to the upper rotating body 7 using the value of the swing angle sensor 19, or may be obtained from the inclination angle sensor 18 attached to the lower running body 5.

[0020] The boom angle sensor 14, arm angle sensor 15, bucket angle sensor 17, tilt angle sensor 18, and swing angle sensor 19 constitute an attitude detection device 53 that detects the rotation angles of the front working implement 2 and the swing angle of the upper swing structure 7, etc.

[0021] An operating device for operating the multiple hydraulic actuators 4a, 4b, 6, 11-13 is installed in the operator's cab 71 provided on the upper swing body 7. Specifically, the operating device includes a right travel lever 23a for operating the right travel hydraulic motor 4a, a left travel lever 23b for operating the left travel hydraulic motor 4b, a right operating lever 22a for operating the boom cylinder 11 and the bucket cylinder 13, and a left operating lever 22b for operating the arm cylinder 12 and the swing hydraulic motor 6. In this embodiment, the right travel lever 23a and the left travel lever 23b are collectively referred to as travel levers 23, and the right travel lever 23a, the left travel lever 23b, the right operating lever 22a, and the left operating lever 22b are collectively referred to as operating levers 22, 23. The operating levers 22, 23 are, for example, electric levers.

[0022] Furthermore, a surrounding information acquisition device 54 (terrain information acquisition device) that acquires information about objects (including the terrain and the ground surface) around the hydraulic excavator 1 is attached to the upper rotating body 7, for example, above the operator's cab 71. The surrounding information acquisition device 54 may be, for example, a LiDAR (Light Detection and Ranging) or a stereo camera. A plurality of surrounding information acquisition devices 54 may be attached to the hydraulic excavator 1. Alternatively, a configuration may be adopted in which information acquired by a surrounding information acquisition device 54 installed at a work site rather than on the hydraulic excavator 1 is acquired via a communication device.

[0023] FIG. 2 is a configuration diagram of a hydraulic system and a control system mounted on the hydraulic excavator 1.

[0024] As shown in FIG. 2 , an engine 103, which is a prime mover mounted on the upper rotating structure 7, drives a hydraulic pump 102 and a pilot pump 104. The control device 40 controls the rotational movement of the front working implement 2, the traveling movement of the undercarriage 5, and the swinging movement of the upper rotating structure 7 in accordance with operation information (amount and direction of operation) of the control levers 22, 23 by the operator. Specifically, the control device 40 detects the operation information (amount and direction of operation) of the control levers 22, 23 by the operator using operation detection devices 52a-52f, and outputs control commands in accordance with the detected operation information to the electromagnetic proportional valves 51a-51l. The electromagnetic proportional valves 51a-51l are provided on a pilot line 100, and are activated when a control command is input from the control device 40, outputting pilot pressure to a flow control valve 101 to operate the flow control valve 101.

[0025] The flow control valve 101 controls the pressurized oil supplied from the hydraulic pump 102 to each of the swing hydraulic motor 6, the arm cylinder 12, the boom cylinder 11, the bucket cylinder 13, the right traveling hydraulic motor 4a, and the left traveling hydraulic motor 4b in accordance with the pilot pressure from the electromagnetic proportional valves 51a to 51l.

[0026] The boom cylinder 11, arm cylinder 12, and bucket cylinder 13 each extend and retract using the supplied pressure oil, rotating the boom 8, arm 9, and bucket 10, respectively. This changes the position and attitude of the bucket 10. The swing hydraulic motor 6 rotates using the supplied pressure oil, causing the upper swing structure 7 to swing. The right traveling hydraulic motor 4a and the left traveling hydraulic motor 4b rotate using the supplied pressure oil, causing the lower traveling structure 5 to travel. Even if the operator does not operate the control levers 22 and 23, the hydraulic actuators 4a, 4b, 6, 11 to 13 can be driven by operating the electromagnetic proportional valves 51a to 51l and the flow control valve 101 according to commands from the control device 40. Even if the operator operates the control levers 22 and 23, the amount of operation by the operator can be limited according to commands from the control device 40.

[0027] Fig. 3 is a functional block diagram illustrating the processing functions of the control device 40 together with the related configuration. Fig. 4 is a side view showing the reference coordinate system together with the hydraulic excavator, Fig. 5 is a rear view, and Fig. 6 is a plan view.

[0028] Although not shown, the control device 40 is a computer including a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and an external I / F (Interface), which are connected to one another via a bus. The external I / F of the control device 40 is connected to an electromagnetic proportional valve 51, an operation detection device 52, an attitude detection device 53, a surrounding information acquisition device 54 (terrain information acquisition device), a notification device 55 (stabilization support device), and a storage device (e.g., a hard disk drive or a large-capacity flash memory), which is not shown.

[0029] The notification device 55 is a device that notifies the operator of information from the control device 40. The notification device 55 is, for example, a display. The notification device 55 may also be equipped with a speaker and may notify the operator using sound.

[0030] In FIG. 3 , the control device 40 includes a coordinate conversion unit 41, an object detection unit 42, a ground area estimation unit 43, a vehicle vicinity area extraction unit 44, an inclination index calculation unit 45, an inclination index storage unit 46, and a vehicle body inclination change determination unit 47.

[0031] A reference coordinate system 300 that specifies the positions and postures of the components of the hydraulic excavator 1 is set in advance in the control device 40. As shown in Figures 4, 5, and 6, the reference coordinate system 300 in this embodiment is defined as a right-handed coordinate system with its origin at the point where the rotation axis 120 of the upper rotating body 7 intersects with the ground contact surface G of the lower traveling body 5. In the reference coordinate system 300, the forward movement direction of the lower traveling body 5 is defined as the positive direction of the X axis. In this embodiment, the reference coordinate system 300 is defined as the direction in which the rotation axis 120 extends upward as the positive direction of the Z axis. In this embodiment, the reference coordinate system 300 is defined as being orthogonal to each of the X axis and the Z axis, and the left side is defined as the positive direction of the Y axis.

[0032] In addition, in the reference coordinate system 300 of this embodiment, the rotation angle of the upper rotating structure 7 is defined as 0 degrees when the front working implement 2 is parallel to the X-axis. When the rotation angle of the upper rotating structure 7 is 0 degrees, the operating plane of the front working implement 2 is parallel to the XZ plane, the direction of the lifting operation of the boom 8 is the positive direction of the Z-axis, and the dumping direction of the arm 9 and bucket 10 is the positive direction of the X-axis.

[0033] Furthermore, the inclination of the lower traveling body 5 in the fore-and-aft direction relative to the direction of gravity is referred to as the lower traveling body pitch angle θlp, the inclination in the lateral direction is referred to as the lower traveling body roll angle θlr, the inclination of the upper rotating body in the fore-and-aft direction is referred to as the upper rotating body pitch angle θup, and the inclination angle in the lateral direction is referred to as the upper rotating body roll angle θur. When the swing angle is 0 degrees, the lower traveling body pitch angle θlp and the upper rotating body pitch angle θup, and the lower traveling body roll angle θlr and the upper rotating body roll angle θur, respectively, are identical. Figures 4 and 5 show a situation where the swing angle is 0 degrees and the lower traveling body pitch angle θlp and the upper rotating body pitch angle θup, and the lower traveling body roll angle θlr and the upper rotating body roll angle θur are identical.

[0034] The coordinate conversion unit 41 converts the point cloud data obtained from the surrounding information acquisition device 54 into point cloud data in the reference coordinate system 300 using the position and attitude of the surrounding information acquisition device 54 relative to the hydraulic excavator 1 and the rotation angle of the upper rotating body 7.

[0035] The object detection unit 42 uses the point cloud data in the reference coordinate system 300 to detect objects of a certain height that exist around the hydraulic excavator 1. Objects to be detected here include other work machines and rocks, and are objects that obstruct the travel of the hydraulic excavator 1.

[0036] The ground surface area estimation unit 43 estimates the area (ground surface area) that is the ground surface around the hydraulic excavator 1 by removing the area in which the object was detected from the area around the hydraulic excavator 1. The ground surface area also includes an approximate plane that has an inclination different from the approximate plane on which the hydraulic excavator 1 is located. For example, if the approximate plane on which the hydraulic excavator 1 is located is an approximate horizontal plane (an approximate plane that is not inclined with respect to the direction of gravity), a sloped surface (an approximate plane that is inclined with respect to the direction of gravity) that is connected to the approximate horizontal plane is also included in the ground surface area.

[0037] The processing by the object detection unit 42 and the ground area estimation unit 43 may be performed on grid data 400 obtained by dividing the area around the hydraulic excavator 1 into a grid pattern with a reference coordinate system 300 as the origin, as shown in Fig. 7. This reduces the calculation load on the control device 40, and enables the information on the ground area to be managed in a unified manner using the grid data 400.

[0038] The running object vicinity area extraction unit 44 extracts a running object vicinity area 500, which is an area including the undercarriage 5 and its vicinity, from the ground area estimated by the ground area estimation unit 43. The size of the running object vicinity area 500 is, for example, the range in which the undercarriage 5 can move during a calculation cycle of the control device 40. The running object vicinity area 500 is indicated by a dashed line in FIG. 7. The running object vicinity area extraction unit 44 also determines whether the running object vicinity area 500 is a single, approximately flat surface. Specifically, if the maximum difference in the direction of the rotation axis 120 between the respective surface positions of the running object vicinity area 500 is equal to or less than a predetermined threshold (first threshold), the running object vicinity area 500 is determined to be a single, approximately flat surface.

[0039] When the running object vicinity area extraction unit 44 determines that the running object vicinity area 500 is a single, substantially flat surface, the inclination index calculation unit 45 calculates the sum of squares of the pitch angle and roll angle of the lower running structure 5 as the inclination index of the running object vicinity area 500. Note that the inclination index may be any value that indicates the magnitude of the inclination, and is not limited to the sum of squares of the pitch angle and roll angle of the lower running structure 5.

[0040] While the hydraulic excavator 1 is moving, i.e., during movement associated with the driving of the crawler 21, the inclination index holding unit 46 determines that the lower running body 5 is moving on an approximate plane having the same inclination index while the running body vicinity area extraction unit 44 determines that the running body vicinity area 500 is a single approximate plane, and continues to hold the inclination index of the running body vicinity area 500 calculated by the inclination index calculation unit 45 at the time when it was first determined that the running body vicinity area 500 was a single approximate plane.

[0041] When the inclination index holding unit 46 holds an inclination index for the region 500 near the vehicle body, the vehicle body inclination change judgment unit 47 calculates the sum of the squares of the pitch angle and roll angle of the lower vehicle body 5 from the attitude detection device 53 as the inclination index for the vehicle body 3 (second inclination index), calculates the difference between the inclination index for the region 500 near the vehicle body that is held (first inclination index) and the second inclination index, and if the difference is greater than or equal to a predetermined threshold value (second threshold value), judges that an inclination of the lower vehicle body 5 has occurred that is different from that predicted from the prior terrain, and activates the stabilization assistance function.

[0042] Next, the notification process in this embodiment will be described with reference to the flowcharts shown in Figures 8 and 9. Figure 8 is a flowchart showing the process of extracting the area 500 near the moving object, and Figure 9 is a flowchart showing the process related to the stabilization support function.

[0043] First, in step S1 in FIG. 8 , the coordinate conversion unit 41 converts the three-dimensional point cloud data acquired by the surrounding information acquisition device 54 into the reference coordinate system 300 of the hydraulic excavator 1 .

[0044] In step S2, the object detection unit 42 detects objects around the hydraulic excavator 1.

[0045] In step S3, the ground area estimation unit 43 estimates the area of ​​the ground around the hydraulic excavator 1.

[0046] In step S4 , the running body vicinity area extraction unit 44 extracts the running body vicinity area 500 , which is the area near the lower running body 5 .

[0047] In step S5, the vehicle vicinity area extraction unit 44 determines whether the vehicle vicinity area 500 is a single, approximately flat surface. If it is determined that it is a single, approximately flat surface, the process proceeds to step S6. If it is not determined that it is a single, approximately flat surface, the process proceeds to step S1.

[0048] In step S6, the inclination index calculation unit 45 calculates the inclination index of the region 500 near the moving object.

[0049] In steps S7 and S8, while the region near the running object 500 is a single, approximately flat surface, the inclination indicator holding unit 46 holds the inclination indicator for the region near the running object 500, and the process proceeds to step S7. If the region near the running object 500 is no longer a single, approximately flat surface, the inclination indicator for the region near the running object 500 is discarded, and the process proceeds to step S9. The process of extracting the region near the running object 500 and the process of determining whether the region near the running object 500 is a single, approximately flat surface are continued.

[0050] In step S9, the inclination indicator holding unit 46 discards the inclination indicator for the region 500 near the moving object.

[0051] 9, in step S100, the vehicle body tilt fluctuation determination unit 47 determines whether the tilt index of the vehicle vicinity area 500 is held, and if it is held, the process proceeds to step S101. If it is not held, the process ends.

[0052] In step S101, the vehicle body tilt fluctuation determination unit 47 calculates the sum of squares of the pitch angle and roll angle of the lower traveling structure 5 (second tilt index).

[0053] In step S102, the difference between the stored inclination index (first inclination index) of the traveling body vicinity region 500 and the calculated sum of squares of the pitch angle and roll angle (second inclination index) of the lower traveling body 5 is compared to determine whether it is equal to or greater than a second threshold. If it is equal to or greater than the second threshold, the process proceeds to step S103, and if it is less than the second threshold, the process ends.

[0054] In step S103, the stabilization support function is activated. The stabilization support function in this embodiment is an alarm function performed by the alarm device 55.

[0055] The effect of performing such processing will be described below.

[0056] As shown in Figure 10, when the hydraulic excavator 1 is traveling on terrain that appears to be a single, substantially flat surface from the outside (terrain on which the inclination of the hydraulic excavator 1 is not expected to fluctuate), if the lower carriage 5 actually reaches the terrain, the inclination of the hydraulic excavator 1 may fluctuate due to reasons such as the terrain being soft or easily collapsing, which may reduce the stability of the hydraulic excavator 1. In this embodiment, by notifying the operator when the inclination of the hydraulic excavator 1 predicted from the prior terrain information differs from the inclination actually occurring on the hydraulic excavator 1, the operator can easily become aware of the inclination of the hydraulic excavator 1, thereby ensuring the stability of the hydraulic excavator 1. Even if the absolute values ​​of the pitch angle or roll angle of the hydraulic excavator 1 with respect to the direction of gravity are small, it is possible to notify the operator when these angles differ from the inclination angles predicted from the prior terrain information.

[0057] Furthermore, by using the sum of the squares of the pitch angle and roll angle of the lower track body 5 as the inclination index, it is possible to handle cases where a turning operation is performed on a sloping surface or where the orientation of the lower track body changes with respect to the surface on the slope while traveling. The lower track body pitch angle θlp, lower track body roll angle θlr, upper swing body pitch angle θup, upper swing body roll angle θur, and swing angle θswg have the following relationship.

[0058]

[0059]

[0060] If we square both sides of the above two equations and add the left and right sides together, we get

[0061]

[0062] It can be seen that the value of the sum of squares is preserved regardless of the turning angle θswg. Here, the turning angle θswg can also be regarded as the orientation of the lower traveling structure 5 with respect to the slope surface. In other words, the sum of squares of the pitch angle θlp and roll angle θlr of the lower traveling structure 5 is preserved regardless of the orientation of the lower traveling structure 5 with respect to the slope surface.

[0063] When the pitch angle θlp and the roll angle θlr of the lower running body 5 alone change, it is not possible to distinguish whether the change in these angles is due to a change in the orientation of the lower running body 5 relative to the slope surface or whether the change in these angles is due to a change in the terrain as a result of running. However, if only the orientation of the lower running body 5 has changed, the sum of the squares of the pitch angle θlp and the roll angle θlr of the lower running body 5 is preserved, making it possible to distinguish between a change in the orientation of the lower running body 5 relative to the slope surface and a change in the shape of the terrain.

[0064] 11 shows a case where the hydraulic excavator 1 is located on a substantially horizontal plane and a slope surface is included in the traveling body vicinity area 500. Fig. 11(a) shows a side view, and Fig. 11(b) shows the state of the grid data 400 at that time. In the grid data 400 in Fig. 11(b), the shaded area represents the slope surface.

[0065] 11 , if the running body vicinity area 500 includes a slope surface that is estimated to be ground but has a slope different from the approximate plane on which the undercarriage 5 is located, the running body vicinity area 500 is not determined to be a single approximate plane, the slope index of the running body vicinity area 500 is not maintained, and the stabilization support function is not activated. With this configuration, the stabilization support function does not operate when the undercarriage 5 enters a slope surface or enters from a slope surface onto an approximately horizontal surface. In other words, if a change in the slope of the undercarriage 5 is predicted based on the terrain in advance, the stabilization support function does not operate, thereby reducing the sense of discomfort felt by the operator.

[0066] 12 shows an example of the operation of the alarm device 55. When an inclination different from the inclination predicted from the terrain occurs, regardless of the magnitude of the pitch angle or roll angle of the hydraulic excavator 1, this is notified.

[0067] Furthermore, the notification device 55 may notify the operator of the extraction result of the running object nearby area 500 by the running object nearby area extraction unit 44. Since the running object nearby area 500 is extracted from an area estimated to be the ground, this configuration allows the operator to easily know that there are no obstacles near the lower running structure 5.

[0068] Furthermore, the notification device 55 may notify whether or not the inclination indicator holding unit 46 holds the inclination indicator of the vehicle body 3. This allows the operator to know in advance whether or not there is a possibility that the stabilization assistance function will be activated.

[0069] (Summary) In the first embodiment, the hydraulic excavator 1 (working machine) includes a lower traveling body 5, an upper rotating body 7 that is attached to the lower traveling body 5 so as to be rotatable about a rotation axis and that constitutes a vehicle body together with the lower traveling body 5, a working device 2 attached to the upper rotating body 7, operation devices 22, 23 for operating the lower traveling body 5, the upper rotating body 7, and the working device 2, an attitude detection device 53 that detects the attitude of the vehicle body 3, a terrain information acquisition device 54 that acquires terrain information around the vehicle body 3, and a control device 40 that controls the operations of the lower traveling body 5, the upper rotating body 7, and the working device 2 in accordance with the operation of the operation levers 22, 23 (operation devices), and the control device 40 is equipped with a stabilization support device 55 that performs support operations to ensure the stability of the vehicle body 3, and the control device 40 is equipped with a ground area estimation unit 43 that estimates a ground area from the terrain information acquired by the terrain information acquisition device 54, and a ground area estimation unit 44 that estimates a ground area from the ground area. a tilt index calculation unit 45 that calculates a tilt index for the traveling body vicinity area 500 when the maximum difference in the axial direction of the rotation axis 120 at each surface position in the traveling body vicinity area 500 becomes equal to or less than a predetermined first threshold; a tilt index holding unit 46 that holds a first tilt index, which is the tilt index calculated by the tilt index calculation unit 45, while the maximum difference remains equal to or less than the first threshold; and a vehicle body tilt change determination unit 47 that calculates a second tilt index, which is the tilt index of the vehicle body 3, from the attitude of the hydraulic excavator 1 detected by the attitude detection device 53, and instructs the stabilization assistance device 55 to perform the assistance operation when the difference between the first tilt index held by the tilt index holding unit 46 and the second tilt index of the vehicle body 3 becomes equal to or greater than a predetermined second threshold.

[0070] According to the first embodiment configured as described above, when the inclination indicator of the vehicle body 3 deviates from the inclination indicator of the vehicle body vicinity area 500 while the hydraulic excavator 1 is traveling in the vehicle body vicinity area 500, which is a single substantially flat surface, the stabilization of the vehicle body 3 is assisted by the stabilization assistance device 55. This makes it possible to ensure the stability of the vehicle body 3 when the hydraulic excavator 1 travels on terrain that appears drivable from the outside but on which the stability of the vehicle body 3 may be lost during travel.

[0071] Furthermore, the inclination index calculation unit 45 according to the first embodiment calculates the sum of squares of the pitch angle θlp and roll angle θlr of the lower running structure 5 as the inclination index of the running structure vicinity region 500, and the vehicle body inclination fluctuation determination unit 47 calculates the sum of squares of the pitch angle θlp and roll angle θlr of the lower running structure 5 as the inclination index of the vehicle body 3. This makes it possible to distinguish and detect inclination fluctuation of the vehicle body 3 caused by deformation of the ground surface from inclination fluctuation of the vehicle body 3 caused by a change in the orientation of the lower running structure 5. Furthermore, by calculating the sum of squares of the pitch angle θup and roll angle θur of the upper rotating structure 7, it is possible to calculate the sum of squares of the pitch angle θlp and roll angle θlr of the lower running structure 5, which makes it possible to install the attitude detection device 53 together with the control device 40 on the upper rotating structure 7. As a result, it is not necessary to route wiring for the attitude detection device 53 through the rotating device to the lower running structure 5.

[0072] Furthermore, in the first embodiment, the hydraulic excavator 1 includes a cab 71 provided on the upper rotating body 7, the stabilization assistance device 55 includes an alarm device 55 provided in the cab 71, and the vehicle body inclination change determination unit 47 instructs the alarm device 55 to issue an alarm when the difference between the first inclination index held by the inclination index holding unit 46 and the second inclination index of the vehicle body 3 becomes equal to or greater than the second threshold value. This makes it possible to prompt the operator to take action to ensure the stability of the vehicle body 3 when an unexpected inclination occurs in the vehicle body 3.

[0073] Furthermore, the notification device 55 according to the first embodiment displays the running body vicinity area 500 extracted by the running body vicinity area extraction unit 44. This allows the operator to easily understand that there is no obstacle near the lower running body 5.

[0074] Furthermore, the notification device 55 according to the first embodiment notifies whether the first tilt index is held by the tilt index holding unit 46. This allows the operator to know in advance whether there is a possibility that the stabilization assistance function will be activated.

[0075] In the second embodiment of the present invention, a configuration will be described in which the stabilization assistance function is a function of intervening in the operation of the operation devices 22 and 23. Note that a description of the same parts as in the first embodiment will be omitted.

[0076] 13 is a functional block diagram of the control device 40 in this embodiment. An operation control unit 48 is added to the first embodiment (shown in FIG. 3). Furthermore, a command from the operation control unit 48 can be received by the electromagnetic proportional valve 51 and the alarm device 55.

[0077] The operation control unit 48 calculates the difference between the stored inclination index of the area near the traveling body and the sum of squares of the pitch angle and roll angle of the undercarriage 5 from the attitude detection device 53 using the vehicle body inclination variation determination unit 47, and when this difference is equal to or greater than a predetermined threshold value (second threshold value), restricts the operation of the hydraulic excavator 1. Here, the second threshold value in this embodiment is set to a value greater than the threshold value (second threshold value) for determining whether to issue a notification in the first embodiment.

[0078] The operation controlled by the operation control unit 48 is, for example, the traveling operation of the hydraulic excavator 1. When the difference between the inclination index of the area near the traveling body that is being held and the sum of the squares of the pitch angle and roll angle of the lower traveling body 5 from the attitude detection device 53 is equal to or greater than a second threshold, the operation amount is limited as operation control. In other words, the operation amount of the traveling lever 23 is limited.

[0079] The operation controlled by the operation control unit 48 is, for example, the operation of the front working mechanism 2 of the hydraulic excavator 1. When the difference between the tilt index of the area near the traveling body being held and the sum of the squares of the pitch angle and roll angle of the lower traveling body 5 from the attitude detection device 53 becomes equal to or greater than a second threshold value, the boom 8 is automatically lowered without operator operation, and the bucket 10 is lowered so that the hydraulic excavator 1 can be easily supported.

[0080] The operation controlled by the operation control unit 48 is the swing operation of the upper rotating unit 7 of the hydraulic excavator 1. For example, as shown in FIG. 14 , while the upper rotating unit 7 swings 90 degrees to the right and the undercarriage 5 is moving forward, the difference between the inclination index of the area near the traveling unit being held and the sum of squares of the pitch angle and roll angle of the undercarriage 5 detected by the attitude detection device 53 becomes equal to or greater than a second threshold value. Furthermore, comparison of the roll angles and pitch angles of the undercarriage 5 before and after the difference becomes equal to or greater than the second threshold value determines that the undercarriage 5 is experiencing a pitch angle in a forward downward direction that is not predicted from the terrain information. In this case, if the center of gravity of the upper rotating unit 7 is located on the opposite side of the front working implement (on the counterweight side), the swing operation of the upper rotating unit 7 to the right is restricted. The center of gravity position can be calculated based on information from the attitude detection device 53. Furthermore, as shown in FIG. 15 , the operation controlled by the operation control unit 48 may be notified by an alarm device 55.

[0081] 16 , the hydraulic excavator 1 may be configured to be remotely controlled by including a remote control device 600 that is arranged at a location remote from the hydraulic excavator 1 and configured to be able to transmit operation commands to the control device 40, a wireless transmitter 601 that transmits operation commands from the remote control device 600, and a wireless receiver 602 that receives the commands transmitted from the wireless transmitter 601. In this case, when the operation control unit 48 intervenes in the operation of the remote control device 600, the remote control device 600 may generate a reaction force in a direction opposite to the direction of operation.

[0082] In extracting the traveling body vicinity region 500, the traveling body vicinity region 500 may be extracted so that the bench edge 211 is not included in the traveling body vicinity region 500. Here, the bench edge 211 is the edge of the bench 210 on which the hydraulic excavator 1 is positioned when the hydraulic excavator 1 performs loading work on the dump truck 200, as shown in FIG. 17 . Because the traveling body vicinity region 500 does not include the area beyond the bench edge 211, when the bench edge 211 is present near the undercarriage 5, displaying the extraction result of the traveling body vicinity region 500 makes it possible for the operator to easily notice the presence of the bench edge 211.

[0083] (Summary) In the second embodiment, the stabilization assistance device 48 has an operation control unit 48 provided in the control device 40 as a function of intervening in the operation of the operating devices 22, 23, and the vehicle body tilt fluctuation determination unit 47 instructs the operation control unit 48 to intervene in the operation of the operating devices 22, 23 so as to suppress tilt fluctuation of the vehicle body 3 when the difference between the first tilt index, which is the tilt index held by the tilt index holding unit 46, and the second tilt index, which is the tilt index of the vehicle body 3, becomes equal to or greater than a predetermined second threshold value.

[0084] According to the second embodiment configured as described above, when an unexpected tilt occurs in the vehicle body 3, the hydraulic excavator 1 operates to suppress fluctuations in the tilt of the vehicle body 3, thereby making it possible to ensure the stability of the vehicle body 3.

[0085] Moreover, in the second embodiment, the stabilization assistance device 48 has an operation control unit 48 provided in the control device 40 as a function of intervening in the operation of the operation device 23, and when the difference between the first inclination indicator held by the inclination indicator holding unit and the second inclination indicator of the vehicle body 3 becomes equal to or greater than the second threshold value, the vehicle body tilt fluctuation determination unit 47 instructs the operation control unit 48 to intervene in the operation of the lower traveling body 5 by the operation device 23 so as to suppress tilt fluctuation of the vehicle body 3. As a result, when an unexpected tilt occurs in the vehicle body 3, the lower traveling body 5 operates to suppress tilt fluctuation of the vehicle body 3, making it possible to ensure the stability of the vehicle body 3.

[0086] Moreover, in the second embodiment, the stabilization assistance device 48 has an operation control unit 48 provided in the control device 40 as a function of intervening in the operation of the operation device 22, and when the difference between the first inclination indicator held by the inclination indicator holding unit 46 and the second inclination indicator of the vehicle body 3 becomes equal to or greater than the second threshold value, the vehicle body tilt change determination unit 47 instructs the operation control unit 48 to intervene in the operation of the upper rotating body 7 or the work device 2 by the operation device 22 so as to suppress inclination fluctuation of the vehicle body 3. As a result, when an unexpected inclination occurs in the vehicle body 3, the upper rotating body 7 or the work device 2 operates so as to suppress inclination fluctuation of the vehicle body 3, making it possible to ensure the stability of the vehicle body 3.

[0087] Furthermore, in the second embodiment, the hydraulic excavator 1 (work machine) is equipped with a remote control device 600 arranged outside the vehicle body, and the control device 40 has a function of controlling the undercarriage 5, the upper rotating body 7, and the work device 2 in accordance with the operation of the remote control device 600. This makes it possible to ensure the stability of the vehicle body 3 when the remotely operated hydraulic excavator 1 travels over terrain that appears drivable from the outside but on which the stability of the vehicle body 3 may be compromised during travel.

[0088] Moreover, in the second embodiment, the operation control unit 48 has a function of intervening in the operation of the remote control device 600, and when the difference between the first inclination indicator held by the inclination indicator holding unit 46 and the second inclination indicator of the vehicle body 3 becomes equal to or greater than the second threshold value, the vehicle body tilt fluctuation determination unit 47 instructs the operation control unit 48 to intervene in the operation of the remote control device 600 so as to suppress tilt fluctuation of the vehicle body 3, and the remote control device 600 generates a reaction force in the opposite direction to the operation direction of the remote control device 600 while the operation control unit 48 is intervening in the operation of the remote control device 600. This makes it possible to notify the operator that the operation direction of the remote control device 600 will reduce the stability of the vehicle body 3.

[0089] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to add part of the configuration of one embodiment to the configuration of another embodiment, or to delete part of the configuration of one embodiment or replace it with part of another embodiment.

[0090] 1... Hydraulic excavator (work machine), 2... Front working device, 3... Vehicle body, 4a... Right-hand hydraulic motor for traveling, 4b... Left-hand hydraulic motor for traveling, 5... Lower traveling body, 6... Swing hydraulic motor, 7... Upper rotating body, 8... Boom, 8a... Boom pin, 9... Arm, 9a... Arm pin, 10... Bucket, 10a... Bucket pin, 11... Boom cylinder, 12... Arm cylinder, 13... Bucket cylinder, 14... Boom angle sensor, 15... Arm angle sensor, 16... Bucket link, 17... Bucket angle sensor, 18... Tilt angle sensor, 19... Swing angle sensor, 21a... Left-hand crawler, 21b... Right-hand crawler, 22a... Right operating lever (operating device), 22b... Left operating lever (operating device), 23a... Right traveling lever (operating device), 23b... Left traveling Lever (operating device), 40...control device, 41...coordinate conversion unit, 42...object detection unit, 43...ground area estimation unit, 44...vehicle vicinity area extraction unit, 45...tilt index calculation unit, 46...tilt index holding unit, 47...vehicle body tilt change determination unit, 48...motion control unit (stabilization support device), 51a to 51l...electromagnetic proportional valves, 52a to 52f...operation detection device, 53...attitude detection device, 54...surrounding information acquisition device (terrain information acquisition device), 55...alarm device (stabilization support device), 71...driver's cab, 100...pilot line, 101...flow control valve, 102...hydraulic pump, 103...engine, 104...pilot pump, 120...swing axis, 200...dump truck, 300...reference coordinate system, 400...grid data, 500...vehicle vicinity area, G...ground surface.

Claims

1. A work machine comprising: a lower running body; an upper rotating body attached to the lower running body so as to be rotatable about a rotating axis and constituting a vehicle body together with the lower running body; a working device attached to the upper rotating body; an operating device for operating the lower running body, the upper rotating body, and the working device; an attitude detection device for detecting the attitude of the vehicle body; a terrain information acquisition device for acquiring terrain information around the vehicle body; and a control device for controlling the operation of the lower running body, the upper rotating body, and the working device in accordance with the operation of the operating device, the work machine comprising: a stabilization support device that performs support operations to ensure the stability of the vehicle body, the control device comprising: a ground area estimation unit that estimates a ground area from the terrain information acquired by the terrain information acquisition device; a vehicle nearby area extraction unit that extracts a vehicle nearby area including the area of ​​the lower running body and an area nearby from the ground area; and a gradient index calculation unit that calculates a gradient index of the vehicle nearby area when a maximum difference in the axial direction of the rotating axis of each surface position in the vehicle nearby area becomes equal to or less than a predetermined first threshold. a tilt index holding unit that holds a first tilt index, which is the tilt index calculated by the tilt index calculation unit, while the state in which the maximum difference is equal to or less than the first threshold continues; and a vehicle body tilt change determination unit that calculates a second tilt index, which is the tilt index of the vehicle body, from the attitude of the work machine detected by the attitude detection device, and that instructs the stabilization assistance device to perform the assistance operation when the difference between the first tilt index held by the tilt index holding unit and the second tilt index of the vehicle body becomes equal to or greater than a predetermined second threshold.

2. A work machine as described in claim 1, wherein the tilt index calculation unit calculates the sum of squares of the pitch angle and roll angle of the lower traveling body as the tilt index of the area near the traveling body, and the vehicle body tilt fluctuation determination unit calculates the sum of squares of the pitch angle and roll angle of the lower traveling body as the tilt index of the vehicle body.

3. A work machine as described in claim 1, comprising a cab provided on the upper rotating body, the stabilization assistance device having an alarm device provided in the cab, and the vehicle body tilt fluctuation determination unit instructs the alarm device to issue an alarm when the difference between the first tilt index held by the tilt index holding unit and the second tilt index of the vehicle body becomes equal to or greater than the second threshold value, which indicates that an unexpected tilt has occurred in the vehicle body.

4. A work machine according to claim 3, wherein the notification device displays the area near the moving object extracted by the area near the moving object extraction unit.

5. A work machine according to claim 3, wherein the notification device notifies whether the first tilt indicator is being held by the tilt indicator holding section.

6. A work machine as described in claim 1, wherein the stabilization assistance device has an operation control unit provided in the control device as a function of intervening in the operation of the operating device, and the vehicle body tilt fluctuation determination unit instructs the operation control unit to intervene in the operation of the operating device so as to suppress tilt fluctuation of the vehicle body when the difference between the first tilt index held by the tilt index holding unit and the second tilt index of the vehicle body becomes equal to or greater than the second threshold value.

7. A work machine as described in claim 1, wherein the stabilization assistance device has an operation control unit provided in the control device as a function of intervening in the operation of the operating device, and the vehicle body tilt fluctuation determination unit instructs the operation control unit to intervene in the operation of the lower traveling body by the operating device so as to suppress tilt fluctuation of the vehicle body when the difference between the first tilt index held by the tilt index holding unit and the second tilt index of the vehicle body becomes equal to or greater than the second threshold value.

8. A work machine as described in claim 1, wherein the stabilization assistance device has an operation control unit provided in the control device as a function of intervening in the operation of the operating device, and the vehicle body tilt fluctuation determination unit instructs the operation control unit to intervene in the operation of the upper rotating body or the work device by the operating device when the difference between the first tilt index held by the tilt index holding unit and the second tilt index of the vehicle body becomes equal to or greater than the second threshold value, so as to suppress tilt fluctuation of the vehicle body.

9. A work machine as claimed in any one of claims 6 to 8, comprising a remote control device arranged outside the vehicle body, the control device having the function of controlling the undercarriage, the upper rotating body and the work equipment in response to the operation of the remote control device.

10. A work machine as described in claim 9, wherein the operation control unit has a function of intervening in the operation of the remote control device, and the vehicle body tilt fluctuation determination unit instructs the operation control unit to intervene in the operation of the remote control device so as to suppress tilt fluctuation of the vehicle body when the difference between the first tilt index held by the tilt index holding unit and the second tilt index of the vehicle body becomes equal to or greater than the second threshold value, and the remote control device generates a reaction force in a direction opposite to the operation direction of the remote control device when the operation control unit intervenes in the operation of the remote control device.

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