Working machinery
The work machine integrates posture and operation detection with a control device to prevent deep excavation, addressing operator inconvenience and productivity issues by automatically controlling the bucket's movement to avoid damaging the travel path.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- HITACHI CONSTRUCTION MACHINERY CO LTD
- Filing Date
- 2024-12-20
- Publication Date
- 2026-07-02
Smart Images
Figure 2026109775000001_ABST
Abstract
Description
Technical Field
[0005]
[0001] The present invention relates to a working machine.
Background Art
[0002] A working machine including an upper revolving body rotatably attached to a lower traveling body and an articulated working device rotatably attached to the upper revolving body is known. The working device has a boom rotatably attached to the upper revolving body, an arm rotatably attached to the boom, and a bucket rotatably attached to the arm.
[0003] The working machine performs an excavation operation of excavating an excavation target such as a slope with the working device, a transportation operation of transporting excavated materials such as earth and sand above the loading platform of a loading machine such as a dump truck, a dumping operation of discharging the excavated materials onto the loading platform of the loading machine, and a return operation of moving the working device to the excavation position, thereby performing an excavation loading operation.
[0004] As an excavation support function for assisting the excavation operation, there is a technique for executing semi-automatic control by operating the working device according to predetermined conditions when the operating device is operated by an operator. In Patent Document 1, as an example of the excavation support function, a technique for automatically switching the target height of the bucket when executing semi-automatic control to a value suitable for the work is described. This Patent Document 1 describes that "a control unit that controls the working machine so that a working tool included in the working machine does not enter a predetermined target shape, and based on the posture of the working tool with respect to a target construction terrain that is a target shape of the finish of the construction target, a switching unit that sets the target shape to an offset terrain separated from the target construction terrain by a predetermined distance or the target construction terrain."
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
[0006] In excavation and loading work sites, the work machinery is positioned on a bench higher than the travel path of the loading machine. The work device rotates downwards to excavate the target area, and then transports and discharges the excavated material to the loading machine. If the work device unintentionally excavates too deep during the excavation operation, it will damage the travel path of the loading machine. Damaged travel path can hinder the movement of the loading machine, requiring leveling work on the travel path. However, leveling the travel path reduces the productivity of the work site. Therefore, to prevent unintentional deep excavation, it is conceivable to apply an excavation support function to the work machinery.
[0007] On the other hand, in order to use the excavation support function described in Patent Document 1, it is necessary to prepare data on the target construction terrain. Furthermore, with the excavation support function described in Patent Document 1, the operator needs to specify the offset amount relative to the target construction terrain and the offset direction, such as whether the offset is upward or downward. This can be time-consuming for the operator, and they may find the excavation support function cumbersome.
[0008] The present invention has been made in view of the above, and aims to provide a work machine equipped with an excavation support function that can reduce the hassle for the operator while preventing unintentional deep excavation. [Means for solving the problem]
[0009] To solve the above problems, the present invention provides a work machine comprising: a work device rotatably attached to a machine body and having a boom, arm and bucket; a posture detection device for detecting the posture of the work device; an operation detection device for detecting operator operation information for the work device; and a control device for assisting the operator's operation of the work device, wherein the control device includes an excavation operation determination unit that determines, based on the detection results of the posture detection device and the operation detection device, whether or not the operator's excavation operation to instruct the work machine to excavate an object to be excavated with the bucket has started, and The device comprises a lower limit height setting unit that sets the height of a lower limit surface that determines the limit of downward movement of the bucket during the excavation operation, and an excavation operation support unit that controls the raising movement of the boom so that the tip of the bucket does not enter below the lower limit surface during the excavation operation, wherein the lower limit height setting unit calculates the height of the lowest point that the tip of the bucket can reach when the arm or the bucket rotates downward from the position of the work device when it is determined that the excavation operation has started, and sets the height of the lower limit surface between the height of the tip of the bucket when it is determined that the excavation operation has started and the height of the lowest point. [Effects of the Invention]
[0010] According to the present invention, it is possible to provide a work machine equipped with an excavation support function that can reduce the hassle for the operator while preventing unintentional deep excavation. Other issues, components, and effects will be clarified by the following description of the embodiments. [Brief explanation of the drawing]
[0011] [Figure 1] Side view of the work machine. [Figure 2] A diagram illustrating how construction machinery operates at a work site. [Figure 3] A diagram illustrating the configuration of a hydraulic system installed in a work machine. [Figure 4] A block diagram illustrating the functional configuration of the control device of the first embodiment. [Figure 5] A diagram showing the reference coordinate system set in the control device shown in FIG. 4. [Figure 6] A diagram for explaining the lower limit height setting unit shown in FIG. 4. [Figure 7] A flowchart showing the processing of the excavation operation determination unit shown in FIG. 4. [Figure 8] A flowchart showing the processing of the lower limit height setting unit shown in FIG. 4. [Figure 9] A flowchart showing the processing of the excavation operation support unit shown in FIG. 4. [Figure 10] A diagram showing the relationship between the distance from the tip of the bucket to the lower limit surface height and the limit value of the velocity vector. [Figure 11] A diagram for explaining an operation example of the working machine when the operator's excavation operation is performed. [Figure 12] A block diagram for explaining the functional configuration of the control device of the second embodiment. [Figure 13] A flowchart showing the processing of the lower limit height setting unit shown in FIG. 12. [Figure 14] A block diagram for explaining the functional configuration of the control device of the third embodiment. [Figure 15] A flowchart showing the processing of the excavation operation determination unit shown in FIG. 14. [Figure 16] A block diagram for explaining the functional configuration of the control device of the fourth embodiment. [Figure 17] A diagram showing an example display of the display device shown in FIG. 16. [Figure 18] A diagram for explaining a remote operation device for operating the working machine of the fifth embodiment.
Embodiments for Carrying Out the Invention
[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each embodiment, components denoted by the same reference numerals have the same components in each embodiment and the description thereof will be omitted unless otherwise specified.
[0013] In this embodiment, a hydraulic excavator equipped with a bucket 10 as a work tool (attachment) at the tip of a work device (front work device 2) will be used as an example to describe the work machine 1. The work machine 1 may be a work machine equipped with attachments other than the bucket 10. The work machine 1 may be a work machine other than a hydraulic excavator, as long as it has a multi-jointed work device that is constructed by connecting multiple members (boom 8, arm 9, attachments, etc.) on a rotatable structure (upper slewing body 7).
[0014] [First Embodiment] A first embodiment of the present invention will be described using Figures 1 to 11. Figure 1 is a side view of the work machine 1. Figure 2 is a diagram illustrating how the work machine 1 works at a work site.
[0015] The work machine 1 excavates the target to be excavated, such as a slope, using the front work device 2, and performs excavation and loading work by loading the excavated material onto the loading platform (vessel) 201 of the loading machine 200, such as a dump truck or other transport machine. The loading machine 200 travels on the travel path 210. The work machine 1 is positioned on the upper surface of the bench 220, which is higher than the travel path 210.
[0016] The work machine 1 performs a series of operations in the excavation and loading operation, including excavation, transport, soil discharge, and return. The work machine 1 repeats these operations multiple times for one loading machine 200. The excavation operation is the operation of excavating the target to be excavated using the bucket 10. The transport operation is the operation of rotating the upper rotating body 7 while holding the excavated material in the bucket 10 to transport the excavated material to the top of the loading platform (vessel) 201 of the loading machine 200. The soil discharge operation is the operation of rotating the bucket 10 in the dump direction to discharge the excavated material onto the loading platform 201 of the loading machine 200. The return operation is the operation of moving the bucket 10 from above the loading platform 201 to the excavation position of the next target to be excavated.
[0017] The work machine 1 comprises a multi-jointed front work device 2 that holds the excavated material and rotates in the vertical or horizontal direction, and a machine body 3 on which the front work device 2 is mounted.
[0018] The machine body 3 comprises a lower traveling body 5 which is driven by a right-travel hydraulic motor 4a and a left-travel hydraulic motor 4b provided on the right and left sides of the lower traveling body 5, and an upper slewing body 7 which is attached to the upper part of the lower traveling body 5 via a slewing device and rotates by a slewing hydraulic motor 6 of the slewing device. In this embodiment, the right-travel hydraulic motor 4a and the left-travel hydraulic motor 4b are collectively referred to as the traveling hydraulic motor 4.
[0019] The front working device 2 is a multi-jointed working device composed of multiple front members attached to the front of the upper slewing body 7. The front working device 2 includes a boom 8 that is rotatably connected in the vertical direction to the front of the upper slewing body 7, an arm 9 that is rotatably connected in the vertical direction to the tip of the boom 8, and a bucket 10 that is rotatably connected in the vertical direction to the tip of the arm 9.
[0020] The boom 8 is connected to the upper slewing body 7 by a boom pin 8a and rotates by the extension and retraction of the boom cylinder 11. The arm 9 is connected to the tip of the boom 8 by an arm pin 9a and rotates by the extension and retraction of the arm cylinder 12. 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 retraction of the bucket cylinder 13.
[0021] A boom angle sensor 14 is attached to the boom pin 8a to detect the rotation angle of the boom 8 relative to the machine body 3 (i.e., the upper slewing body 7). An arm angle sensor 15 is attached to the arm pin 9a to detect the rotation angle of the arm 9 relative to the boom 8. A bucket angle sensor 17 is attached to the bucket link 16 to detect the rotation angle of the bucket 10 relative to the arm 9.
[0022] The rotation angles of the boom 8, arm 9, and bucket 10 may also be obtained by detecting the angles of the boom 8, arm 9, and bucket 10 relative to a reference plane such as the horizontal plane using an inertial measurement unit (IMU) and converting them to rotation angles. Alternatively, the rotation angles of the boom 8, arm 9, and bucket 10 may also be obtained by detecting the strokes of the boom cylinder 11, arm cylinder 12, and bucket cylinder 13 using stroke sensors and converting them to rotation angles.
[0023] An inclination angle sensor 18 is attached to the upper slewing body 7 to detect the inclination angle of the machine body 3 with respect to a reference plane such as a horizontal plane. A slewing angle sensor 19 is attached to the slewing device between the lower traveling body 5 and the upper slewing body 7 to detect the slewing angle of the upper slewing body 7 with respect to the lower traveling body 5.
[0024] The boom angle sensor 14, arm angle sensor 15, bucket angle sensor 17, tilt angle sensor 18, and slewing angle sensor 19 constitute an attitude detection device 53 that detects the tilt angle of the machine body 3, the rotation angles of the front work device 2, and the slewing angle of the upper slewing body 7, etc.
[0025] An operating device for operating multiple hydraulic actuators 4, 6, 11, 12, and 13 is installed in the operator's cab 71 located in the upper slewing 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 bucket cylinder 13, and a left operating lever 22b for operating the arm cylinder 12 and slewing hydraulic motor 6. In this embodiment, the right travel lever 23a, left travel lever 23b, right operating lever 22a, and left operating lever 22b are collectively referred to as operating levers 22 and 23. For example, electric lever type operating levers may be used for operating levers 22 and 23. Operating levers 22 and 23 include switches that can specify whether the control is enabled or disabled.
[0026] Figure 3 is a diagram illustrating the configuration of the hydraulic system installed on the work machine 1.
[0027] The engine 103, which is the prime mover mounted on the upper slewing body 7, drives the main hydraulic pump 102 and the pilot pump 104. The control device 40 controls the rotational movement of the front work device 2, the travel movement of the lower traveling body 5, and the slewing movement of the upper slewing body 7 according to the operation information (operation amount and direction) of the operation levers 22 and 23 by the operator. Specifically, the control device 40 detects the operation information of the operation levers 22 and 23 by the operator using sensors 52a to 52f such as rotary encoders or potentiometers, and outputs control commands to electromagnetic proportional valves 51a to 51l according to the detected operation information. The electromagnetic proportional valves 51a to 51l are located on the pilot line 100 and operate when a control command is input from the control device 40, outputting pilot pressure to the flow control valve 101 and operating the flow control valve 101. In this embodiment, the sensors 52a to 52f that detect the operation information of the operating levers 22 and 23 by the operator are collectively referred to as the operation detection device 52.
[0028] The flow control valve 101 controls the pressure oil supplied from the hydraulic pump 102 to the swing hydraulic motor 6, arm cylinder 12, boom cylinder 11, bucket cylinder 13, travel right hydraulic motor 4a, and travel left hydraulic motor 4b, respectively, according to the pilot pressure from the electromagnetic proportional valves 51a to 51l. Electromagnetic proportional valves 51a and 51b output pilot pressure to the flow control valve 101 to control the pressure oil supplied to the swing hydraulic motor 6. Electromagnetic proportional valves 51c and 51d output pilot pressure to the flow control valve 101 to control the pressure oil supplied to the arm cylinder 12. Electromagnetic proportional valves 51e and 51f output pilot pressure to the flow control valve 101 to control the pressure oil supplied to the boom cylinder 11. Electromagnetic proportional valves 51g and 51h output pilot pressure to the flow control valve 101 to control the pressure oil supplied to the bucket cylinder 13. The solenoid proportional valves 51i and 51j output pilot pressure to the flow control valve 101 to control the pressurized oil supplied to the right travel hydraulic motor 4a. The solenoid proportional valves 51k and 51l output pilot pressure to the flow control valve 101 to control the pressurized oil supplied to the left travel hydraulic motor 4b.
[0029] The boom cylinder 11, arm cylinder 12, and bucket cylinder 13 extend and retract using supplied pressurized oil, respectively, to rotate the boom 8, arm 9, and bucket 10. This changes the position and orientation of the bucket 10. The slewing hydraulic motor 6 rotates using supplied pressurized oil to slewing the upper slewing body 7. The travel right hydraulic motor 4a and travel left hydraulic motor 4b rotate using supplied pressurized oil to move the lower travel body 5. Even when there is no operation of the operating levers 22 and 23 by the operator, the control device 40 can activate the electromagnetic proportional valves 51a to 51l and the flow control valve 101, thereby driving the hydraulic actuators 4, 6, 11, 12, and 13. In this embodiment, the electromagnetic proportional valves 51a to 51l are collectively referred to as electromagnetic proportional valve 51.
[0030] Figure 4 is a block diagram illustrating the functional configuration of the control device 40 of the first embodiment. Figure 5 is a diagram illustrating the reference coordinate system set in the control device 40 shown in Figure 4. Figure 6 is a diagram illustrating the lower limit height setting unit 44 shown in Figure 4.
[0031] Although not shown in the diagram, the control device 40 is composed of a computer in which a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and external I / F (Interface) are connected to each other 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, and a storage device (e.g., a hard disk drive or high-capacity flash memory).
[0032] The control device 40 is pre-set with a reference coordinate system that specifies the position and orientation of the components of the work machine 1. As shown in Figure 5, the reference coordinate system in this embodiment is defined as a right-handed coordinate system with the origin O being the point on the pivot axis where the lower traveling body 5 and the ground surface G are in contact. The reference coordinate system defines the forward direction of the lower traveling body 5 as the positive direction of the X axis. The reference coordinate system defines the direction in which the pivot axis extends upward as the positive direction of the Z axis. The reference coordinate system defines the left direction of the left-right direction of the lower traveling body 5, which is perpendicular to the X axis and Z axis respectively, as the positive direction of the Y axis.
[0033] In the reference coordinate system of this embodiment, the rotation angle of the upper slewing body 7 is defined as 0 degrees when the front working device 2 is parallel to the X-axis. When the rotation angle of the upper slewing body 7 is 0 degrees, the operating plane of the front working device 2 is parallel to the XZ plane. The positive direction of the Z-axis is the direction of the upward movement of the boom 8 (hereinafter also referred to as the "upward direction"), and the negative direction of the Z-axis is the direction of the downward movement of the boom 8 (hereinafter also referred to as the "downward direction"). The positive direction of the X-axis is the direction of the dumping movement of the arm 9 and bucket 10 (hereinafter also referred to as the "dumping direction"), and the negative direction of the X-axis is the direction of the clouding movement of the arm 9 and bucket 10 (hereinafter also referred to as the "clouding direction").
[0034] The control device 40 has an excavation support function that assists the operator's excavation operation by instructing the excavation operation of the work machine 1 that excavates the target to be excavated with the bucket 10. To realize this excavation support function, the control device 40 has a posture calculation unit 41, an operation speed calculation unit 42, an excavation operation determination unit 43, a lower limit height setting unit 44, an excavation operation support unit 45, and an actuator control unit 46.
[0035] The posture calculation unit 41 calculates the posture of the components of the work machine 1 in the reference coordinate system based on the detection results of the posture detection device 53. Specifically, the posture calculation unit 41 calculates the rotation angle θbm of the boom 8 with respect to the X axis from the detection signal of the rotation angle of the boom 8 output from the boom angle sensor 14. The posture calculation unit 41 calculates the rotation angle θam of the arm 9 with respect to the boom 8 from the detection signal of the rotation angle of the arm 9 output from the arm angle sensor 15. The posture calculation unit 41 calculates the rotation angle θbk of the bucket 10 with respect to the arm 9 from the detection signal of the rotation angle of the bucket 10 output from the bucket angle sensor 17. The posture calculation unit 41 calculates the rotation angle θsw of the upper slewing body 7 with respect to the X axis (lower traveling body 5) from the detection signal of the slewing angle of the upper slewing body 7 output from the slewing angle sensor 19.
[0036] Furthermore, the attitude calculation unit 41 calculates the planar position and height of the boom 8, arm 9, and bucket 10 based on the calculated rotation angles θbm, θam, θbk of the front working device 2 and the rotation angle θsw of the upper slewing body 7, as well as the length Lbm of the boom 8, the length La of the arm 9, and the length Lbk of the bucket 10. The length Lbm of the boom 8 is the length from the boom pin 8a to the arm pin 9a. The length Lam of the arm 9 is the length from the arm pin 9a to the bucket pin 10a. The length Lbk of the bucket 10 is the length from the bucket pin 10a to the tip of the bucket 10. Also, when the rotation angle θsw is 0 degrees, the boom pin 8a is offset by Lox in the positive X-axis direction from the rotation center axis.
[0037] The operating speed calculation unit 42 calculates the speeds of the boom cylinder 11, arm cylinder 12, and bucket cylinder 13 based on the amount of operation of the operating levers 22 and 23 by the operator detected by the operation detection device 52. For example, the control device 40's storage device has a table pre-stored that shows the correlation between the amount of operation of the operating levers 22 and 23 and the speeds of the boom cylinder 11, arm cylinder 12, and bucket cylinder 13. The operating speed calculation unit 42 can use this table to estimate the speeds of the boom cylinder 11, arm cylinder 12, and bucket cylinder 13. Furthermore, the operating speed calculation unit 42 calculates the speeds (angular velocities) of the boom 8, arm 9, and bucket 10 from the speeds of the boom cylinder 11, arm cylinder 12, and bucket cylinder 13 based on the posture of the front work device 2 calculated by the posture calculation unit 41. Alternatively, the operating speed calculation unit 42 may calculate the angular velocities of the boom 8, arm 9, and bucket 10 by calculating the time change of each angle detected by the boom angle sensor 14, arm angle sensor 15, and bucket angle sensor 17. Alternatively, the operating speed calculation unit 42 may directly acquire the angular velocities of the boom 8, arm 9, and bucket 10 from sensors that detect these angular velocities.
[0038] The excavation operation determination unit 43 determines whether or not the operator has started excavation based on the detection results of the attitude detection device 53 and the operation detection device 52. Specifically, the excavation operation determination unit 43 determines whether or not excavation has started based on the amount of operation of the operator's operating levers 22 and 23 detected by the operation detection device 52 and the attitude of the front work device 2 calculated by the attitude calculation unit 41. More specifically, the excavation operation determination unit 43 determines whether or not the operator has started excavation based on the amount of operation of the arm 9 or bucket 10 in the cloud direction by the operator and the positional relationship between the ground surface G of the lower traveling body 5 and the bucket pin 10a (tip of the arm 9). More precisely, the excavation operation determination unit 43 determines that an excavation operation has started when the bucket pin 10a is located below the height of the ground contact surface G of the lower traveling body 5 (hereinafter also referred to as "ground contact height 83"), at least one of the arm 9 and the bucket 10 is operated in the cloud direction, neither the arm 9 nor the bucket 10 is operated in the dump direction, and the boom 8 is not operated in the downward direction.
[0039] The lower limit height setting unit 44 sets the height of the lower limit surface (hereinafter also referred to as "lower limit surface height 80") which determines the limit of downward movement of the bucket 10 during the operator's excavation operation. Specifically, first, the lower limit height setting unit 44 obtains the height of the tip of the bucket 10 in the reference coordinate system (hereinafter also referred to as "excavation start height 81") when the excavation operation determination unit 43 determines that the excavation operation has started. The lower limit height setting unit 44 also calculates the height of the lowest point in the reference coordinate system (hereinafter also referred to as "lowest point height 82") that the tip of the bucket 10 can reach if the arm 9 or bucket 10 rotates downward from the posture of the front work device 2 (the rotation angles θbm, θam, θbk of the boom 8, arm 9, and bucket 10) when the excavation operation determination unit 43 determines that the excavation operation has started. The lower limit height setting unit 44 then sets the lower limit surface height 80 between the excavation start height 81 and the lowest point height 82.
[0040] The lowest point height 82 can be calculated by fixing the rotation angle θbm of the boom 8 when it is determined that the excavation operation has started, as shown in Figure 6, and calculating the position that is moved downward by the length Lam of the arm 9 and the length Lbk of the bucket 10 from the position of the arm pin 9a. In Figure 6, the boom 8, arm 9, and bucket 10 when it is determined that the excavation operation has started are shown with solid lines. In Figure 6, the boom 8, arm 9, and bucket 10 when the tip of the bucket 10 reaches the lowest point height 82 are shown with dashed lines. Note that Figure 6 shows the case where the rotation angle θbk of the bucket 10 does not change from 0 degrees, and the rotation angle θam of the arm 9 changes. In the reference coordinate system, when the rotation angle θbk of the bucket 10 is 0 degrees, the lowest point height 82 is the height of the tip of the bucket 10 when the sum of the rotation angle θbm of the boom 8 and the rotation angle θam of the arm 9 is 90 degrees.
[0041] When setting the lower limit surface height 80, the lower limit height setting unit 44 may set the lower limit surface height 80 to a height midway between the excavation start height 81 and the lowest point height 82. Alternatively, the lower limit height setting unit 44 may set the lower limit surface height 80 to a height a predetermined amount below the excavation start height 81. In this case, the lower limit height setting unit 44 can change the predetermined amount according to the excavation start height 81. For example, the lower limit height setting unit 44 can change the predetermined amount so that the distance from the excavation start height 81 to the lower limit surface height 80 becomes smaller the lower the excavation start height 81 is located in the reference coordinate system.
[0042] The excavation operation support unit 45 controls the front work device 2 so that the tip of the bucket 10 does not go below the lower limit surface set by the lower limit height setting unit 44 during excavation. Specifically, the excavation operation support unit 45 controls the raising operation of the boom 8 so that the tip of the bucket 10 does not go below the lower limit surface set by the lower limit height setting unit 44 during excavation. In this embodiment, when the operator operates the operating levers 22 and 23 to rotate the arm 9 toward the cloud, the excavation operation support unit 45 calculates a target speed for the raising operation of the boom 8 so that the tip of the bucket 10 does not go below the said lower limit surface. This target speed for the raising operation of the boom 8 is a type of excavation support request speed that the excavation operation support unit 45 requests in order to automatically control the front work device 2 as excavation operation support. However, this target speed for the raising operation of the boom 8 is not a target speed for accurately excavating the excavation target to a desired target shape, but rather a target speed to prevent unintentionally excavating the excavation target to a deep depth. Therefore, the algorithm of the drilling operation support unit 45 can be simple, and the computational load on the drilling operation support unit 45 can be small.
[0043] The actuator control unit 46 outputs a control signal to the electromagnetic proportional valve 51 so that the boom cylinder 11, arm cylinder 12, and bucket cylinder 13 operate according to the target speed of the front work device 2 calculated by the excavation operation support unit 45. In this embodiment, the actuator control unit 46 outputs a control signal to the electromagnetic proportional valve 51 so that the boom cylinder 11 operates according to the target speed related to the raising operation of the boom 8.
[0044] The operation of the control device 40 and the work machine 1 will be explained using Figures 7 to 11. Figure 7 is a flowchart showing the processing of the excavation operation determination unit 43 shown in Figure 4. The excavation operation determination unit 43 performs the processing shown in Figure 7 at predetermined control cycles.
[0045] In step S101, the excavation operation determination unit 43 determines, based on the posture of the front work device 2 calculated by the posture calculation unit 41, whether the bucket pin 10a is located below the ground contact height 83 of the lower traveling body 5 in the reference coordinate system. If the bucket pin 10a is located below the ground contact height 83 of the lower traveling body 5, the excavation operation determination unit 43 proceeds to step S102. If the bucket pin 10a is not located below the ground contact height 83 of the lower traveling body 5, the excavation operation determination unit 43 proceeds to step S106.
[0046] In step S102, the drilling operation determination unit 43 determines whether the amount of operation of at least one of the arm 9 and bucket 10 in the cloud direction (hereinafter also referred to as "cloud operation amount") is greater than or equal to a threshold, based on the amount of operation of the operating levers 22 and 23 by the operator detected by the operation detection device 52. If the cloud operation amount of at least one of the arm 9 and bucket 10 is greater than or equal to the threshold, the drilling operation determination unit 43 proceeds to step S103. If the cloud operation amount of at least one of the arm 9 and bucket 10 is less than the threshold, the drilling operation determination unit 43 proceeds to step S106.
[0047] In step S103, the excavation operation determination unit 43 determines whether the amount of operation in the lowering direction of the boom 8 (hereinafter also referred to as the "boom lowering operation amount") is less than a threshold, based on the amount of operation of the operating levers 22 and 23 by the operator detected by the operation detection device 52. If the boom lowering operation amount is less than the threshold, the excavation operation determination unit 43 proceeds to step S104. If the boom lowering operation amount is equal to or greater than the threshold, the excavation operation determination unit 43 proceeds to step S106.
[0048] In step S104, the excavation operation determination unit 43 determines whether the amount of operation in the dumping direction of both the arm 9 and the bucket 10 (hereinafter also referred to as "dumping operation amount") is less than a threshold, based on the amount of operation of the operating levers 22 and 23 by the operator detected by the operation detection device 52. If the dumping operation amounts of both the arm 9 and the bucket 10 are less than the threshold, the excavation operation determination unit 43 proceeds to step S105. If the dumping operation amount of either the arm 9 or the bucket 10 is greater than or equal to the threshold, the excavation operation determination unit 43 proceeds to step S106.
[0049] In step S105, the excavation operation determination unit 43 determines that the operator has started excavation. The excavation operation determination unit 43 then sets the excavation operation flag, which indicates that the excavation operation has started, to "TRUE" as a result of its determination. After that, the excavation operation determination unit 43 terminates the process shown in Figure 7.
[0050] In step S106, the excavation operation determination unit 43 determines that the operator has not started excavation. The excavation operation determination unit 43 then sets the excavation operation flag to "FALSE" as a result of its determination. After that, the excavation operation determination unit 43 terminates the process shown in Figure 7.
[0051] Figure 8 is a flowchart showing the process of the lower limit height setting unit 44 shown in Figure 4. The lower limit height setting unit 44 performs the process shown in Figure 8 at predetermined control cycles.
[0052] In step S201, the lower height setting unit 44 determines whether the excavation operation flag is TRUE or not. If the excavation operation flag is TRUE, the lower height setting unit 44 proceeds to step S202. If the excavation operation flag is FALSE, the lower height setting unit 44 proceeds to step S206.
[0053] In step S202, the lower height setting unit 44 determines whether the drilling operation flag set in the previous control cycle is FALSE. If the drilling operation flag set in the previous control cycle is FALSE, the lower height setting unit 44 proceeds to step S203. If the drilling operation flag set in the previous control cycle is TRUE, the lower height setting unit 44 proceeds to step S207.
[0054] In step S203, the lower limit height setting unit 44 obtains the height of the tip of the bucket 10 in the reference coordinate system when it is determined that the excavation operation has started, i.e., the excavation start height 81.
[0055] In step S204, the lower limit height setting unit 44 calculates the height in the reference coordinate system of the lowest point that the tip of the bucket 10 can reach, i.e., the lowest point height 82, when the arm 9 or bucket 10 rotates downward from the position of the front work device 2 when it is determined that the excavation operation has started.
[0056] In step S205, the lower limit height setting unit 44 calculates and sets the lower limit surface height 80 in the reference coordinate system from the excavation start height 81 obtained in step S203 and the lowest point height 82 calculated in step S204. After that, the lower limit height setting unit 44 completes the process shown in Figure 8.
[0057] In step S206, the lower limit height setting unit 44 determines that the excavation operation has not started, and therefore sets the lower limit surface height 80 to a value far below in the reference coordinate system so that the boom 8 is not raised by the control of the excavation operation support unit 45. For example, the lower limit height setting unit 44 sets the lower limit surface height 80 to -40m, which is approximately twice the length of the front work device 2. After that, the lower limit height setting unit 44 completes the process shown in Figure 8.
[0058] In step S207, the lower limit height setting unit 44 continues to maintain the lower limit surface height 80 set in the previous control cycle because the excavation operation is in progress (i.e., the work machine 1 is in the middle of an excavation operation). After that, the lower limit height setting unit 44 completes the process shown in Figure 8.
[0059] Figure 9 is a flowchart showing the processing of the excavation operation support unit 45 shown in Figure 4. Figure 10 is a diagram showing the relationship between the distance D from the tip of the bucket 10 to the lower limit surface height 80 and the limit value az of the velocity vector B. The excavation operation support unit 45 performs the processing shown in Figure 9 at predetermined control cycles. The excavation operation support unit 45 can utilize the contents described in Japanese Patent Application Publication No. 2021-1439.
[0060] In the process shown in Figure 9, as shown in the legend in the upper right of Figure 9, it is assumed that a velocity vector B is generated at the tip of the bucket 10 by the operator's excavation operation. The lifting operation of the boom 8, which generates a velocity vector C, is automatically added to the excavation operation that generates the velocity vector B, so that the component of the velocity vector B generated at the tip of the bucket 10 that is perpendicular to the lower limit surface (hereinafter also referred to as the "vertical component bz") is limited to a predetermined limit value az, as shown in Figure 10.
[0061] In step S301, the excavation operation support unit 45 calculates the velocity vector B of the tip of the bucket 10 generated by the excavation operation, based on the angular velocities of the boom 8, arm 9, and bucket 10 calculated by the operation speed calculation unit 42 and the attitude of the boom 8, arm 9, and bucket 10 calculated by the attitude calculation unit 41.
[0062] In step S302, the excavation operation support unit 45 calculates the distance D from the tip of the bucket 10 to the lower limit surface height 80 based on the position of the tip of the bucket 10 calculated by the attitude calculation unit 41 and the lower limit surface height 80 set by the lower limit height setting unit 44. Then, the excavation operation support unit 45 calculates a limit value az corresponding to the calculated distance D based on the graph shown in Figure 10. The limit value az is calculated to limit the vertical component bz of the velocity vector B generated at the tip of the bucket 10.
[0063] In step S303, the drilling operation support unit 45 obtains the vertical component bz of the velocity vector B calculated in step S301.
[0064] In step S304, the drilling operation support unit 45 determines whether the limit value az calculated in step S302 is 0 or greater. If the limit value az is 0 or greater, the drilling operation support unit 45 proceeds to step S305. If the limit value az is less than 0, the drilling operation support unit 45 proceeds to step S310.
[0065] The excavation operation support unit 45 has an xz coordinate system set up as shown in the legend of Figure 9. In this xz coordinate system, the x-axis is a coordinate axis parallel to the lower limit plane, and the z-axis is a coordinate axis perpendicular to the lower limit plane. The positive direction of the x-axis is the cloud direction of the arm 9 and bucket 10, and the positive direction of the z-axis is the upward direction of the boom 8. In the legend shown in Figure 9, the vertical component bz and the limit value az are negative, and the horizontal component bx, the horizontal component cx, and the vertical component cz are positive. Also, the legend shown in Figure 9 assumes a situation where the lower limit plane is located below the tip of the bucket 10. From the graph shown in Figure 10, when the limit value az is 0, the distance D is 0, meaning the tip of the bucket 10 is on the lower limit plane. When the limit value az is positive, the distance D is negative, meaning the tip of the bucket 10 is below the lower limit plane. When the limit value az is negative, the distance D is positive, meaning the tip of the bucket 10 is above the lower limit plane. If it is determined in step S304 that the limit value az is 0 or greater, it means that the tip of the bucket 10 is located on or below the lower limit surface.
[0066] In step S305, the drilling operation support unit 45 determines whether the vertical component bz obtained in step S303 is 0 or greater. If the vertical component bz is 0 or greater, the drilling operation support unit 45 proceeds to step S306. If the vertical component bz is less than 0, the drilling operation support unit 45 proceeds to step S307. A positive vertical component bz indicates that the vertical component bz of the velocity vector B is upward, and a negative vertical component bz indicates that the vertical component bz of the velocity vector B is downward.
[0067] In step S306, the drilling operation support unit 45 compares the absolute value of the limit value az with the absolute value of the vertical component bz. If the absolute value of the limit value az is greater than or equal to the absolute value of the vertical component bz, the drilling operation support unit 45 proceeds to step S307. If the absolute value of the limit value az is less than the absolute value of the vertical component bz, the drilling operation support unit 45 proceeds to step S312.
[0068] In step S307, the excavation operation support unit 45 selects "cz = az - bz" as the formula for calculating the component cz (hereinafter also referred to as "vertical component cz") perpendicular to the lower limit plane of the velocity vector C at the tip of the bucket 10 that should be generated by the raising motion of the boom 8. Then, the excavation operation support unit 45 substitutes the limit value az calculated in step S302 and the vertical component bz obtained in step S303 into the selected formula to calculate the vertical component cz.
[0069] In step S308, the drilling operation support unit 45 calculates a velocity vector C that can output the vertical component cz calculated in step S307, and calculates a component cx (hereinafter also referred to as "horizontal component cx") parallel to the lower limit plane of the calculated velocity vector C.
[0070] In step S309, the excavation operation support unit 45 calculates the target velocity vector T of the tip of the bucket 10. The component of the target velocity vector T perpendicular to the lower limit plane is denoted as tz (hereinafter also referred to as "vertical component tz"), and the component parallel to the lower limit plane is denoted as tx (hereinafter also referred to as "horizontal component tx"). The vertical component tz of the target velocity vector T is expressed as "tz = bz + cz". The horizontal component tx of the target velocity vector T is expressed as "tx = bx + cx". Substituting the equation from step S307 (cz = az - bz) into this, the vertical component tz and horizontal component tx of the target velocity vector T become "tz = az, tx = bx + cx". That is, when step S309 is reached, the vertical component tz of the target velocity vector T is limited to the limit value az, and the raising operation of the boom 8 is automatically controlled.
[0071] In step S310, the drilling operation support unit 45 determines whether the vertical component bz obtained in step S303 is 0 or greater. If the vertical component bz is 0 or greater, the drilling operation support unit 45 proceeds to step S312. If the vertical component bz is less than 0, the drilling operation support unit 45 proceeds to step S311.
[0072] In step S311, the drilling operation support unit 45 compares the absolute value of the limit value az with the absolute value of the vertical component bz. If the absolute value of the limit value az is greater than or equal to the absolute value of the vertical component bz, the drilling operation support unit 45 proceeds to step S312. If the absolute value of the limit value az is less than the absolute value of the vertical component bz, the drilling operation support unit 45 proceeds to step S307.
[0073] In step S312, the excavation operation support unit 45 does not need to perform the raising operation of the boom 8, so the velocity vector C is set to zero.
[0074] In step S313, the excavation operation support unit 45 calculates the target velocity vector T of the tip of the bucket 10. Specifically, based on the equation (tz=bz+cz, tx=bx+cx) from step S309, the excavation operation support unit 45 determines that the vertical component tz and horizontal component tx of the target velocity vector T are "tz=bz, tx=bx". That is, the target velocity vector T at the time of step S313 coincides with the velocity vector B of the tip of the bucket 10 generated by the operator's excavation operation. After that, the excavation operation support unit 45 proceeds to step S314.
[0075] In step S314, the excavation operation support unit 45 calculates the target speed of the front working device 2 based on the target velocity vector T(tz,tx) calculated in step S309 or S313. Specifically, the excavation operation support unit 45 calculates the target speed for the raising operation of the boom 8 so that the speed of the tip of the bucket 10 follows the target velocity vector T calculated in step S309 or S313. After that, the excavation operation support unit 45 completes the process shown in Figure 9.
[0076] As shown in Figure 9, if the vertical component bz of velocity vector B exceeds the limit value az, the boom 8 is automatically raised to generate velocity vector C. This keeps the vertical component of the velocity vector at the tip of the bucket 10 at the limit value az. As shown in Figure 10, the limit value az is set to approach zero as the tip of the bucket 10 approaches the lower limit surface. However, the horizontal component of the velocity vector at the tip of the bucket 10 is the sum of the horizontal components of velocity vectors B and C and is not limited. Therefore, even when the tip of the bucket 10 is located above the lower limit surface, the excavation operation support unit 45 can move the tip of the bucket 10 along the lower limit surface, preventing the tip of the bucket 10 from going below the lower limit surface without interfering with the operator's excavation operation.
[0077] Figure 11 illustrates an example of the operation of the work machine 1 when the operator performs an excavation operation.
[0078] Figure 11 shows the work machine 1 located on the bench 220. The dotted lines in Figure 11 indicate the positions of the arm 9 and bucket 10 when the boom 8 does not rotate from the position of the front work device 2 when it is determined that the excavation operation has started, and the arm 9 and bucket 10 rotate to the lowest point height 82.
[0079] When the operator moves the arm 9 toward the cloud to perform an excavation operation in which the bucket 10 excavates the target 230, the lower limit height setting unit 44 of the work machine 1 automatically sets the lower limit surface height 80. Then, the work machine 1 automatically raises the boom 8 to prevent the tip of the bucket 10 from going below the lower limit surface height 80 during the operator's excavation operation.
[0080] Since the work machine 1 can automatically set the lower limit height 80, it is not necessary to have the operator perform an operation separate from the normal excavation operation to set the lower limit height 80, nor is it necessary for the operator to prepare prior design data for setting the lower limit height 80. Therefore, the work machine 1 can reduce the burden on the operator. Generally, in excavation operations, the operator takes into account that the position of the tip of the bucket 10 will decrease as the arm 9 is moved toward the cloud, and starts moving the arm 9 toward the cloud from a position higher than the lower limit height 80 intended by the operator. According to this embodiment, the work machine 1 sets the lower limit height 80 below the excavation start height 81, so it can automatically set the lower limit height 80 to match the operator's sense.
[0081] Furthermore, the working machine 1 automatically raises the boom 8 to prevent the tip of the bucket 10 from entering below the lower limit surface height 80 during the operator's excavation operation, thus preventing the bucket 10 from unintentionally excavating too deep and damaging the travel path 210 of the loading machine 200. In addition, the working machine 1's excavation support function does not interfere with the operator's excavation operation. Moreover, the working machine 1 determines whether or not the operator's excavation operation has started based on the amount of movement of the arm 9 or bucket 10 in the cloud direction by the operator and the positional relationship between the bucket pin 10a and the ground surface G. As a result, the working machine 1 can operate the excavation support function (raising the boom 8) only when the operator is performing an excavation operation, thus preventing malfunctions of the excavation support function.
[0082] The work machine 1 performs excavation and loading work by repeatedly performing excavation, transport, soil discharge, and return operations. Generally, the transport and soil discharge operations are performed with the bucket pin 10a positioned above the ground contact height 83 of the lower traveling body 5. Therefore, even if the operator moves the arm 9 or bucket 10 in the cloud direction for the purpose of adjusting the position of the bucket 10 for transport or soil discharge operations, the work machine 1 does not determine that the operator's excavation operation has started. Thus, the work machine 1 can prevent the excavation support function from operating unintentionally during transport and soil discharge operations. Furthermore, generally, during the return operation, the operator operates the boom 8 in the downward direction and the arm 9 and bucket 10 in the dump direction to position the bucket 10 at the next excavation position. If the operator operates the boom 8 in the downward direction or the arm 9 and bucket 10 in the dump direction, the work machine 1 does not determine that the operator's excavation operation has started. Thus, the work machine 1 can prevent the excavation support function from operating unintentionally during the return operation. Therefore, the work machine 1 can only operate the excavation support function (raising the boom 8) when the operator is performing the excavation operation, thus preventing malfunctions of the excavation support function.
[0083] Furthermore, since the work machine 1 can set the lower limit surface height 80 to a height midway between the excavation start height 81 and the lowest point height 82, the distance from the excavation start height 81 to the lower limit surface height 80 can be changed according to the height of the excavation start height 81. Therefore, the work machine 1 can set the lower limit surface height 80 to suit the operator's senses.
[0084] Furthermore, since the work machine 1 can set the lower limit surface height 80 to a predetermined amount below the excavation start height 81, the distance from the excavation start height 81 to the lower limit surface height 80 can be kept constant regardless of the height of the excavation start height 81. Therefore, the work machine 1 can set the lower limit surface height 80 to a position that is always a fixed distance away from the excavation start height 81, which meets the needs of the operator. In addition, the work machine 1 can change the predetermined amount according to the height of the excavation start height 81. For example, the work machine 1 can reduce the predetermined amount so that the distance from the excavation start height 81 to the lower limit surface height 80 becomes smaller the lower the excavation start height 81 is. For the operator, the lower the excavation start height 81, the longer the distance from which they can look down on the tip of the bucket 10, making it difficult to judge the distance to the bucket 10, and thus it is easy to excavate too deep unintentionally. The work machine 1 can set a lower limit surface height 80 that is in line with the operator's senses by reducing the predetermined amount as the starting excavation height 81 decreases, while reliably preventing the bucket 10 from unintentionally excavating too deep.
[0085] Thus, according to the first embodiment, it is possible to provide a work machine 1 equipped with an excavation support function that can reduce the hassle for the operator while preventing unintentional deep excavation.
[0086] [Second Embodiment] A second embodiment of the present invention will be described using Figures 12 and 13. In the second embodiment, the lower limit surface height 80 will be described in relation to the pressure of the hydraulic cylinders 11 to 13. In the second embodiment, the same components as in the first embodiment will not be described.
[0087] Figure 12 is a block diagram illustrating the functional configuration of the control device 40 of the second embodiment.
[0088] A load detection device 54 is connected to the control device 40 of the second embodiment. The load detection device 54 is a device that detects the load (hereinafter also referred to as "cylinder load") applied to the hydraulic cylinders 11 to 13 of the front work device 2. The load detection device 54 is composed of pressure sensors that detect the pressure of the boom cylinder 11, the arm cylinder 12, and the bucket cylinder 13, respectively. The lower limit height setting unit 44 of the second embodiment sets the lower limit surface height 80 based on the detection result of the load detection device 54.
[0089] Figure 13 is a flowchart showing the processing of the lower limit height setting unit 44 shown in Figure 12. In the flowchart shown in Figure 13, steps S208 and S209 are added after step S202 in the flowchart shown in Figure 8. In the flowchart shown in Figure 13, the processing of steps S201, S203 to S207 is the same as in the flowchart shown in Figure 8.
[0090] In step S202, the lower limit height setting unit 44 proceeds to step S207, similar to step S202 in Figure 8, if the drilling operation flag set in the previous control cycle is TRUE. However, if the drilling operation flag set in the previous control cycle is FALSE, it proceeds to step S208.
[0091] In step S208, the lower height setting unit 44 determines whether the cylinder load detected by the load detection device 54 is above a threshold. This threshold is a value that distinguishes whether the tip of the bucket 10 has come into contact with the object to be excavated. If the cylinder load is above the threshold, the lower height setting unit 44 proceeds to step S209. If the cylinder load is below the threshold, the lower height setting unit 44 proceeds to step S203.
[0092] In step S209, the lower limit height setting unit 44 acquires the height of the tip of the bucket 10 in the reference coordinate system when it is determined that the excavation operation has started, i.e., the excavation start height 81. The lower limit height setting unit 44 then sets the acquired excavation start height 81 to the lower limit surface height 80. After that, the lower limit height setting unit 44 completes the process shown in Figure 13.
[0093] As described above, in the second embodiment, when the bucket 10 comes into contact with the object to be excavated, the lower limit height setting unit 44 sets the excavation start height 81, which is the height of the tip of the bucket 10 when it is determined that the operator's excavation operation has started, to the lower limit surface height 80. As a result, the work machine 1 of the second embodiment can only operate the excavation support function (raising the boom 8) when the operator performs an excavation operation and the bucket 10 is actually excavating the object to be excavated, thereby reliably preventing malfunctions of the excavation support function.
[0094] [Third Embodiment] A third embodiment of the present invention will be described with reference to Figures 14 and 15. In the third embodiment, the determination of whether or not the operator's excavation operation has started will be described based on the operator's operation of switch 55. In the third embodiment, the same components as in the first embodiment will not be described.
[0095] Figure 14 is a block diagram illustrating the functional configuration of the control device 40 of the third embodiment.
[0096] A switch 55 is connected to the control device 40 of the third embodiment. The switch 55 is a switch that outputs a signal indicating that the excavation operation has been started by an operator's operation. The switch 55 is located inside the operator's cab 71. The switch 55 may be attached to, for example, the operating levers 22, 23 (specifically, the right operating lever 22a or the left operating lever 22b). The operator can indicate that the excavation operation is about to start by operating the switch 55 to the ON state. The switch 55 may be a momentary switch that outputs a signal indicating the ON state only for the duration that it is pressed. The excavation operation determination unit 43 of the third embodiment determines whether or not the excavation operation has started based on the signal indicating the ON state output from the switch 55.
[0097] Figure 15 is a flowchart showing the processing of the excavation operation determination unit 43 shown in Figure 14. In the flowchart shown in Figure 15, steps S107 and S108 are added before step S101 in the flowchart shown in Figure 7. In the flowchart shown in Figure 15, the processing of steps S101 to S106 is the same as in the flowchart shown in Figure 7.
[0098] In step S107, the drilling operation determination unit 43 determines whether the switch 55 is in the ON state by determining whether or not a signal indicating the ON state has been output from the switch 55. If the signal is output from the switch 55, the drilling operation determination unit 43 determines that the switch 55 is in the ON state and proceeds to step S101. If the signal is not output from the switch 55, the drilling operation determination unit 43 determines that the switch 55 is in the OFF state and proceeds to step S108.
[0099] In step S108, the drilling operation determination unit 43 determines whether the drilling operation flag set in the previous control cycle is FALSE. If the drilling operation flag set in the previous control cycle is FALSE, the drilling operation determination unit 43 proceeds to step S106. If the drilling operation flag set in the previous control cycle is TRUE, the drilling operation determination unit 43 proceeds to step S101.
[0100] In Figure 15, when the operator turns switch 55 to the ON position to start the drilling operation, the drilling operation flag is set to TRUE. After the drilling operation flag is set to TRUE, even if switch 55 is not turned to the ON position, the drilling operation flag remains TRUE if "Yes" is determined in steps S101 to S104.
[0101] Thus, the excavation operation determination unit 43 of the third embodiment determines whether or not the operator has started an excavation operation based on the signal output from the switch 55. This allows the work machine 1 of the third embodiment to explicitly indicate that the operator is performing an excavation operation as a signal from the switch 55, and prevents the unnecessary operation of the excavation support function when the operator performs an operation that is similar to an excavation operation but does not require the operation of the excavation support function. In addition, if "Yes" is determined in steps S101 to S104, the excavation operation flag of the work machine 1 of the third embodiment is maintained as TRUE. As a result, the work machine 1 of the third embodiment does not need to perform an excavation operation while the operator has operated the switch 55 to the ON state, thus reducing the hassle for the operator.
[0102] [Fourth Embodiment] A fourth embodiment of the present invention will be described with reference to Figures 16 and 17. In the fourth embodiment, the content displayed on the display device 56 when the set lower limit surface height 80 is reached will be described. In the fourth embodiment, the same components as in the first embodiment will not be described.
[0103] Figure 16 is a diagram illustrating the functional configuration of the control device 40 of the fourth embodiment. Figure 17 is a diagram showing an example of the display of the display device 56 shown in Figure 16.
[0104] A display device 56 is connected to the control device 40 of the fourth embodiment. The display device 56 displays a figure 62 indicating the lower limit surface at the lower limit surface height 80 set by the lower limit height setting unit 44. The display device 56 is installed in the operator's cab 71. When the lower limit surface height 80 is set, the display device 56 displays a figure 62 indicating the lower limit surface. The figure 62 may be a line (for example, a straight line) along the lower limit surface, as shown in Figure 17. The display device 56 may also display an icon 61 indicating the current position and orientation of the bucket 10, regardless of whether the lower limit surface height 80 has been set. The display device 56 may also display a message 63 indicating that the excavation support function is in operation.
[0105] As a result, the working machine 1 of the fourth embodiment allows the operator to easily understand the positional relationship between the bucket 10 and the lower limit surface height 80. Furthermore, the working machine 1 of the fourth embodiment allows the operator to easily understand whether or not the excavation support function is in operation.
[0106] [Fifth Embodiment] A fifth embodiment of the present invention will be described using Figure 18. In the fifth embodiment, the details of the invention being applied to a work machine 1 that is remotely controlled will be described. In the fifth embodiment, the same components as in the first embodiment will not be described.
[0107] Figure 18 is a diagram illustrating a remote control device 300 for operating the work machine 1 of the fifth embodiment.
[0108] In the fifth embodiment, the work machine 1 is operated by a remote control device 300 located at a remote location away from the work machine 1. The remote control device 300 includes a communication device 301 that communicates with the communication device 70 of the work machine 1, a remote control lever 302 operated by a remote operator, and a display 303 that displays the area around the work machine 1, including the object to be excavated.
[0109] Furthermore, the work machine 1 may communicate with the remote control device 300 via a relay device (not shown). In this case, the work machine 1 and the relay device may communicate via wired or wireless communication. The relay device and the remote control device 300 may communicate via wired or wireless communication.
[0110] A remote operator can operate the work machine 1 by operating the remote control lever 302 while viewing the excavation target displayed on the display 303. The operator's operation information for the remote control lever 302 is transmitted from the communication device 301 to the communication device 70 of the work machine 1. The communication device 70 of the work machine 1 receives the operation information transmitted from the communication device 301 of the remote control device 300 and outputs it to the control device 40. The control device 40 controls the work machine 1 according to the operation information transmitted from the communication device 301 of the remote control device 300.
[0111] In this remotely operated fifth embodiment of the work machine 1, the control device 40, similar to the first embodiment, automatically sets the lower limit surface height 80 and controls the raising operation of the boom 8 so that the tip of the bucket 10 does not enter below the lower limit surface during the excavation operation. Therefore, according to the fifth embodiment, similar to the first embodiment, it is possible to provide a work machine 1 equipped with an excavation support function that reduces the hassle for the operator while preventing unintentional deep excavation.
[0112] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are described in detail to make the present invention easier to understand, and are not necessarily limited to those comprising all the components described. Furthermore, it is possible to replace some of the components of one embodiment with components of another embodiment, and it is also possible to add components of another embodiment to the components of one embodiment. In addition, it is possible to add, delete, or replace some of the components of each embodiment with components of other embodiments.
[0113] Furthermore, each of the above-mentioned components, functions, processing units, or processing means may be implemented in hardware, in whole or in part, for example, by designing them as integrated circuits. Alternatively, each of the above-mentioned components or functions may be implemented in software by a processor interpreting and executing programs that implement each function. Information such as programs, tables, or files that implement each function can be stored in a recording device such as memory, a hard disk, or an SSD (solid state drive), or in a recording medium such as an IC card, SD card, or DVD.
[0114] Furthermore, the control lines and information lines shown are those deemed necessary for explanatory purposes, and not all control lines and information lines are necessarily shown in the actual product. In reality, it can be assumed that almost all components are interconnected. [Explanation of symbols]
[0115] 1...Working machine, 2...Front working device (working device), 3...Machine body, 8...Boom, 9...Arm, 10...Bucket, 40...Control device, 41...Attitude calculation unit, 42...Operation speed calculation unit, 43...Excavation operation determination unit, 44...Lower limit height setting unit, 45...Excavation operation support unit, 46...Actuator control unit, 52...Operation detection device, 53...Attitude detection device, 54...Load detection device, 55...Switch, 56...Display device, 61...Icon, 62...Shape, 63...Message, 70...Communication device, 81...Excavation start height, 80...Lower limit surface height, 82...Lowest point height, 83...Ground contact height, 300...Remote control device
Claims
1. A working device that is rotatably mounted to the machine body and has a boom, arm and bucket, A posture detection device for detecting the posture of the work device, An operation detection device for detecting operator operation information for the work device, A control device that assists the operator's operation of the work device, A work machine equipped with, The control device is Based on the detection results of the attitude detection device and the operation detection device, an excavation operation determination unit determines whether or not the operator has started the excavation operation to instruct the work machine to excavate the target to be excavated by the bucket, A lower limit height setting unit that sets the height of the lower limit surface that determines the downward movement limit of the bucket during the excavation operation, The excavation operation support unit controls the raising motion of the boom so that the tip of the bucket does not enter below the lower limit surface during the excavation operation, The lower limit height setting unit is, When it is determined that the excavation operation has started, the height of the lowest point that the tip of the bucket can reach is calculated if the arm or the bucket rotates downward from the position of the work device at that time. The height of the lower limit surface is set between the height of the tip of the bucket and the height of the lowest point when it is determined that the excavation operation has started. A work machine characterized by the following features.
2. The bucket is rotatably connected to the tip of the arm, The excavation operation determination unit determines whether or not the excavation operation has started based on the amount of movement of the arm or bucket by the operator in the cloud direction and the relative height between the ground surface of the machine body and the tip of the arm. The work machine according to feature 1.
3. The lower limit height setting unit sets the height of the lower limit surface to the height midway between the height of the bucket tip when it is determined that the excavation operation has started and the height of the lowest point. The work machine according to feature 2.
4. The lower limit height setting unit sets the height of the lower limit surface to a predetermined amount below the height of the bucket tip when it is determined that the excavation operation has started. The work machine according to feature 2.
5. The lower limit height setting unit changes the predetermined amount according to the height of the bucket tip when it is determined that the excavation operation has started. The work machine according to feature 4.
6. When the bucket comes into contact with the object to be excavated, the lower limit height setting unit sets the height of the tip of the bucket at the time it is determined that the excavation operation has started to the height of the lower limit surface. The work machine according to feature 2.
7. The system further includes a display device that displays a figure indicating the lower limit surface at the height of the lower limit surface set by the lower limit height setting unit. The work machine according to feature 1.
8. The system further includes a switch that outputs a signal indicating that the excavation operation has been initiated by the operator, The excavation operation determination unit determines whether or not the excavation operation has started based on the signal output from the switch. The work machine according to feature 1.
9. It is further equipped with a communication device for communicating with the remote control device, The communication device receives operation information transmitted from the remote control device and outputs it to the control device. The control device controls the work machine in accordance with the operation information transmitted from the remote control device. The work machine according to feature 1.