Work machine target operation setting system

Abstract

To suppress a floating state of a machine body when a work machine operates according to a target operation.SOLUTION: A work machine target operation setting system 1 comprises: a machine body 10a, a tilt detection device 21b, an attachment 15, and a controller 30. The controller 30 determines whether or not the machine body 10a is in a floating state relative to the ground surface based on a tilt of the machine body 10a detected by the tilt detection device 21b. The controller 30 performs a target operation change process when a target operation change condition set in the controller 30 is satisfied. The target operation change process is a process for changing the target operation toward a side where the tilt of the machine body 10a becomes smaller. The target operation change conditions include that the machine body 10a is in a floating state.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a work machine target motion setting system that sets a target motion of a work machine. [Background technology]

[0002] For example, Patent Document 1 describes a technique for creating an excavation plan (target operation) for a bucket based on soil type and topographical information. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-188362 A Summary of the Invention [Problem to be solved by the invention]

[0004] When a work machine performs work according to a target motion, the bottom surface of the machine body may become lifted above the contact surface of the machine body. It is desirable to be able to suppress this lifting state.

[0005] Therefore, an object of the present invention is to provide a work machine target movement setting system that can suppress the floating state of the machine body when the work machine operates in accordance with a target movement. [Means for solving the problem]

[0006] The work machine target motion setting system includes a machine body, a tilt detection device, an attachment, and a controller. The tilt detection device detects the tilt of the machine body. The attachment is attached to the machine body. The attachment has a bucket for performing excavation work. The controller sets a target motion for excavation motion with the bucket. The controller determines whether or not the machine body is in a floating state relative to the ground surface based on the tilt of the machine body detected by the tilt detection device. The controller performs a target motion change process when a target motion change condition set in the controller is satisfied. The target motion change process is a process for changing the target motion to a side where the tilt of the machine body becomes smaller. The target motion change condition includes the machine body being in a floating state. Effect of the Invention

[0007] The above-described work machine target motion setting system can suppress the floating state of the machine body when the work machine operates in accordance with the target motion. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a side view of a work machine 10 of a work machine target movement setting system 1. [Diagram 2] 1 is a block diagram of a work machine target movement setting system 1. FIG. [Diagram 3] FIG. 2 is a side view of the working machine 10 when the machine body 10a shown in FIG. 1 is in a front-floating state. [Figure 4] FIG. 4 is a side view of the target path P and the like that have been changed due to the machine body 10a shown in FIG. 3 being in a front-floating state. [Diagram 5] FIG. 2 is a side view of the working machine 10 when the machine body 10a shown in FIG. 1 is in a rear-floating state. [Figure 6] FIG. 6 is a side view of the target path P and the like that has been changed due to the machine body 10a shown in FIG. 5 being in a rear-floating state. [Figure 7]FIG. 2 is a side view of the work machine 10 when the machine body 10a shown in FIG. 1 is in a front-floating state and the bucket 15c cannot be positioned at the excavation start target bucket ground angle θs. [Figure 8] FIG. 8 is a side view of the target route P and the like in which the target excavation start position Ps shown in FIG. 7 has been changed to a position X1 forward from the position shown in FIG. [Figure 9] 9 is a flowchart of a process relating to the excavation start target bucket ground angle θs and the target excavation start position Ps shown in FIGS. 7 and 8. [Figure 10] 10 is a diagram showing a bucket height H15c and the like that are stored when the machine main body 10a shown in FIG. 1 is in a rear floating state. FIG. [Figure 11] 3 is a graph showing the relationship between the inclination of the machine body 10a shown in FIG. 1 and the amount of change in the target motion by the controller 30 shown in FIG. 2. [Figure 12] 3 is a graph showing the relationship between the working time of the working machine 10 shown in FIG. 1 and the integrated change amount of the target operation by the controller 30 shown in FIG. 2. [Figure 13] 12 is a flowchart of a process for limiting an integrated change amount using an integrated change amount limiting value shown in FIG. 11 . [Figure 14] FIG. 2 is a side view of the work machine 10 in a case where the operating direction of the attachment 15 is changed when the machine main body 10a shown in FIG. 1 is in a floating state. [Figure 15] 2 is a side view of the work machine 10 when a change is made to the elements to be operated of the attachment 15 shown in FIG. 1. FIG. [Figure 16] 2 is a side view of the work machine 10 when the operation of the bucket 15c shown in FIG. 1 is changed to an unloading operation. [Figure 17] 3 is a flowchart of a process of the controller 30 shown in FIG. 2. [Figure 18] 18 is a flowchart showing the process (S50) of "handling the front floating state in the current excavation operation" shown in FIG. 17. [Figure 19] 18 is a flowchart showing the process (S70) of "dealing with the post-floating state in the current excavation operation" shown in FIG. 17. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The work machine target movement setting system 1 will be described with reference to FIGS.

[0010] 1, the work machine target movement setting system 1 is a system that sets a target movement of a work machine 10. The work machine target movement setting system 1 includes the work machine 10 and a controller 30.

[0011] The work machine 10 is a machine that performs work. For example, the work machine 10 is a construction machine that performs construction work. For example, the work machine 10 is a shovel. The work machine 10 may be configured to be operable by automatic control. The automatic control may be automatic driving or semi-automatic driving (machine control described later). The work machine 10 may operate without using automatic control. The work machine 10 may be operated by a worker (operator) on board the work machine 10, or may be remotely operated. The following mainly describes the case where the work machine 10 is a shovel. The work machine 10 includes a machine body 10a, an attachment 15, an actuator 17, a drive control unit 19 (see FIG. 2), and an attitude sensor 21.

[0012] The machine body 10a is the main body of the work machine 10. The machine body 10a includes a lower traveling body 11 and an upper rotating body 13. The lower traveling body 11 can travel on a traveling surface (such as the ground). The lower traveling body 11 may include crawlers or wheels. The upper rotating body 13 is mounted on the lower traveling body 11 so as to be able to rotate. The direction perpendicular to the rotation axis of the upper rotating body 13 relative to the lower traveling body 11 is defined as the up-down direction Z. In the up-down direction Z, the side (direction) from the lower traveling body 11 toward the upper rotating body 13 is defined as the upper side Z1, and the opposite side to the upper side Z1 is defined as the lower side Z2. The direction in which the rotation axis of the attachment 15 (more specifically, the boom 15a) relative to the machine body 10a extends is defined as the machine body lateral direction. The direction intersecting (for example, perpendicular to) each of the up-down direction Z and the machine body lateral direction is defined as the front-rear direction X. In the front-rear direction X, the side where the attachment 15 protrudes from the upper rotating body 13 is defined as a front side X1, and the side opposite to the front side X1 is defined as a rear side X2. When the machine body 10a is placed on a horizontal plane, the up-down direction Z is the vertical direction.

[0013] The attachment 15 is a part that performs work. The attachment 15 is attached to the machine body 10a. For example, the attachment 15 includes a boom 15a, an arm 15b, and a bucket 15c. The boom 15a is attached to the upper rotating body 13 so as to be able to rise and fall (to be able to rotate up and down). The arm 15b is attached to the boom 15a so as to be able to rotate (to be able to rotate in the front-back direction X and the up-down direction Z).

[0014] The bucket 15c performs an excavation operation, which is an operation to excavate a work object. The work object is an object that is the target of the work machine 10 (the bucket 15c). The work object is, for example, soil, granules, chips, powder, etc. Specifically, the work object is earth and sand. The bucket 15c is a tip attachment provided at the tip of the attachment 15. The bucket 15c is attached to the arm 15b so as to be rotatable (rotatable in the front-rear direction X and the up-down direction Z). The direction of rotation of the bucket 15c to the rear side X2 with respect to the arm 15b is defined as the excavation side R1. The direction of rotation of the bucket 15c to the front side X1 with respect to the arm 15b is defined as the discharge side R2. The angle of the bucket 15c with respect to the reference direction is called the ground angle of the bucket 15c. The above-mentioned "reference direction" may be a direction along the surface of the work object to be excavated by the bucket 15c (an excavation surface, for example, the ground), or may be a horizontal direction. The ground angle of the bucket 15c is, for example, an angle of a specific surface of the bucket 15c (for example, a bucket opening surface 15c1) with respect to a certain reference direction. A target value (target angle) of the ground angle of the bucket 15c is a target bucket ground angle θ described later. The bucket 15c includes a bucket opening surface 15c1, a bucket tip back surface 15c3, a bucket tip portion 15c5, and a bucket specific portion 15c7.

[0015] The bucket opening surface 15c1 is the opening surface of the bucket 15c. The bucket tip back surface 15c3 is provided on the tip side portion of the bucket 15c (the portion on the side farther from the connection portion to the arm 15b). The bucket tip back surface 15c3 is disposed on the front side X1 portion of the bucket 15c when the bucket 15c is disposed so that the bucket opening surface 15c1 faces the upper rotating body 13. The bucket tip back surface 15c3 is, for example, flat. The bucket tip portion 15c5 is the tip portion of the bucket 15c (the end portion on the side farther from the connection portion to the arm 15b). The bucket tip portion 15c5 is, for example, claw-shaped (bucket tooth). The bucket specific portion 15c7 is a portion targeted to be disposed on a target path P (described later). For example, the bucket specific portion 15c7 is a portion controlled to be disposed on the target path P in the automatic control of the work machine 10. The bucket specific portion 15c7 may be, for example, the bucket tip portion 15c5. The bucket specific portion 15c7 may be the base end portion of the bucket 15c (the portion connected to the arm 15b).

[0016] The actuator 17 is a device that moves the work machine 10. The actuator 17 may include a hydraulic actuator that is driven by hydraulic pressure, or may include an electric actuator that is driven by electricity. The actuator 17 may include a motor, or may include an extendable cylinder. The actuator 17 includes a cylinder that moves the attachment 15. The actuator 17 includes a boom cylinder 17a, an arm cylinder 17b, and a bucket cylinder 17c. The boom cylinder 17a raises and lowers the boom 15a relative to the upper rotating body 13. The boom cylinder 17a is, for example, a cylinder (hydraulic cylinder) that is driven (extends and retracts) by hydraulic pressure (the same applies to the arm cylinder 17b and the bucket cylinder 17c). The arm cylinder 17b rotates the arm 15b relative to the boom 15a. The bucket cylinder 17c rotates the bucket 15c relative to the arm 15b.

[0017] The drive control unit 19 (see FIG. 2) controls the actuator 17. The drive control unit 19 may include a hydraulic circuit that controls the hydraulic actuator 17. The drive control unit 19 may include an electric circuit that controls the electric actuator 17.

[0018] The attitude sensor 21 detects the attitude of the work machine 10. A part or all of the attitude sensor 21 may be mounted on the work machine 10. A part or all of the attitude sensor 21 may be disposed outside the work machine 10 (for example, at a work site, etc.) and does not have to be a component of the work machine 10. The attitude sensor 21 includes a reference position sensor 21a, a tilt detection device 21b, a rotation sensor 21c, a boom sensor 21d, an arm sensor 21e, and a tip attachment sensor 21f.

[0019] The reference position sensor 21a detects the position and orientation of a reference portion of the work machine 10 with respect to the work site. The reference portion of the work machine 10 may be, for example, a specific portion of the upper rotating body 13, for example, a mounting portion (boom foot) of the boom 15a to the upper rotating body 13, or for example, the center of rotation of the upper rotating body 13 with respect to the lower traveling body 11. The reference position sensor 21a may perform detection using a positioning system using electromagnetic waves (light, radio waves, etc.). For example, the positioning system may be a satellite positioning system, for example, a global navigation satellite system (GNSS), or a system using a (terrestrial) transmitter and receiver without using a satellite. For example, the positioning system may use a total station. In FIG. 1, the reference position sensor 21a is indicated by the symbol of the reference position sensor 21a at the position of the GNSS antenna when the reference position sensor 21a performs detection using a positioning system using the GNSS.

[0020] The inclination detection device 21b detects the inclination of the machine body 10a. The inclination detection device 21b detects the inclination of the machine body 10a with respect to the horizontal direction. The inclination detection device 21b detects the inclination of the upper rotating body 13 with respect to the horizontal direction. The inclination detection device 21b detects the pitch angle of the machine body 10a with respect to the horizontal direction. The pitch angle is the inclination angle of the central axis of the machine body 10a extending in the front-to-rear direction X with respect to the horizontal direction. The inclination detection device 21b can detect whether the pitch angle of the machine body 10a is front-up or rear-up. "Front-up" is a state in which the central axis of the machine body 10a extending in the front-to-rear direction X is positioned upward (up in the vertical direction) toward the front side X1. "Rear-up" is a state in which the central axis of the machine body 10a extending in the front-to-rear direction X is positioned upward (up in the vertical direction) toward the rear side X2. The tilt detector 21b may be capable of detecting the roll angle of the machine body 10a, or may be capable of detecting the yaw angle of the machine body 10a.

[0021] The tilt detection device 21b may include, for example, a gyro sensor, an acceleration sensor, or an inertial measurement device. The tilt detection device 21b may detect the tilt of the machine body 10a based on the information of the image detected by the imaging device. In this case, the imaging device is included in the tilt detection device 21b. The reference position sensor 21a, the rotation sensor 21c, the boom sensor 21d, the arm sensor 21e, and the tip attachment sensor 21f may also use the information of the image detected by the imaging device. The tilt detection device 21b may detect the tilt of the machine body 10a based on image recognition of a two-dimensional image. The tilt detection device 21b may detect the tilt of the machine body 10a based on a three-dimensional image (distance image) having depth information. The tilt detection device 21b may detect the tilt of the machine body 10a based on a three-dimensional image and a two-dimensional image. The imaging device that detects the image may be a passive type or an active type. Specifically, the imaging device may include a camera (monocular camera) that detects two-dimensional information. The imaging device may include a stereo camera that detects three-dimensional information. The imaging device may detect three-dimensional information of an imaging target by irradiating waves such as electromagnetic waves to the imaging target and detecting the reflected waves. The imaging device may include a TOF (Time Of Flight) sensor that detects distance based on the time from irradiation of waves to return of the reflected waves, or a sensor that detects distance based on the frequency of the reflected waves. The imaging device may include a device that detects three-dimensional information using light (e.g., laser light), and may include, for example, LiDAR (Light Detection and Ranging). The imaging device may include a device that detects three-dimensional information using radio waves (e.g., millimeter wave radar, etc.). Only one imaging device may be provided, or multiple imaging devices may be provided. Only one type of imaging device (e.g., one type) may be used, or multiple types of imaging devices may be combined.

[0022] The rotation sensor 21c detects the rotation angle of the upper rotating body 13 relative to the lower traveling body 11. The rotation sensor 21c may include an angle sensor attached to the rotation shaft or a rotation support part (such as a rotation bearing) of the upper rotating body 13 relative to the lower traveling body 11.

[0023] The boom sensor 21d detects the attitude of the boom 15a. The boom sensor 21d detects the angle (tilt, rotation angle) of the boom 15a with respect to the horizontal direction or the upper rotating body 13. The arm sensor 21e and the tip attachment sensor 21f may also detect the angle with respect to the horizontal direction or the angle with respect to the components of the work machine 10. The boom sensor 21d may include an angle sensor (e.g., a rotary encoder, etc.) attached to the rotation shaft or rotation support part of the boom 15a with respect to the upper rotating body 13. The arm sensor 21e and the tip attachment sensor 21f may also include the angle sensor. The boom sensor 21d may include a sensor that detects the tilt of the boom 15a with respect to the horizontal direction. The arm sensor 21e and the tip attachment sensor 21f may also include a sensor that detects the tilt with respect to the horizontal direction. The boom sensor 21d may include a stroke sensor that detects the stroke of the boom cylinder 17a. The arm sensor 21e and the tip attachment sensor 21f may also include a stroke sensor. The arm sensor 21e detects the posture of the arm 15b. The tip attachment sensor 21f detects the posture of the tip attachment sensor 21f. In the example shown in Fig. 1, the tip attachment sensor 21f is attached to a link member that connects the arm 15b, the bucket 15c, and the bucket cylinder 17c.

[0024] The controller 30 is a computer that performs input and output of signals, calculation (processing), storage of information, etc. For example, the function of the controller 30 shown in FIG. 2 is realized by executing a program stored in the memory unit 30b of the controller 30 in the calculation unit 30a. The controller 30 and other devices may be connected by wireless communication or by wired communication. For example, the detection result is input to the controller 30 from the attitude sensor 21. For example, the controller 30 (more specifically, the operation control unit 33) controls the operation of the work machine 10 (see FIG. 1). For example, the controller 30 outputs a command (signal) for operating the work machine 10 to the drive control unit 19. The controller 30 may be mounted on the work machine 10 or may be disposed outside the work machine 10. The controller 30 may be disposed in a distributed manner in multiple parts (a distributed system may be configured). The controller 30 includes a calculation unit 30a that performs calculation (processing) of information, and a memory unit 30b. Focusing on the functions of the controller 30, the controller 30 includes a target motion setting section 31 and a motion control section 33.

[0025] The memory unit 30b stores information. The memory unit 30b stores programs. For example, the memory unit 30b stores the inclination state of the machine body 10a determined by the controller 30 (specifically, the floating state, the front floating state, and the rear floating state, which will be described later). For example, the memory unit 30b stores the bucket height H15c (see FIG. 10) (the floating state bucket height, which will be described later) when the machine body 10a is in the floating state.

[0026] The target operation setting unit 31 sets a target operation of the work machine 10 (see FIG. 1) (described in detail later).

[0027] The movement control unit 33 controls the movement (movement) of the work machine 10. The movement control unit 33 outputs commands to the drive control unit 19. The movement control unit 33 may output commands to the drive control unit 19 in response to operation by an operator. The movement control unit 33 may automatically control the work machine 10 (see FIG. 1) so that the work machine 10 moves in accordance with a target movement. In this case, the movement control unit 33 automatically controls the movement of the work machine 10 based on the detection value of the attitude sensor 21.

[0028] (Operation of Work Machine 10) 1 may be operated by an operator in the cab 13a, may be remotely operated by an operator from outside the work machine 10 (by a remote control device), or may be automatically operated. The work machine 10 is a machine that utilizes information and communication technology (ICT) (e.g., ICT construction machine).

[0029] For example, the work machine 10 may be operated by an operator using a machine guidance (MG) system function. Specifically, a target operation is set in the controller 30. Then, guidance such as the position to work at is shown to the operator so that the work machine 10 can operate (work) in accordance with the target operation. This guidance is output, for example, to an output device provided in the cab 13a of the work machine 10 or an output device provided in a remote control device. Then, the operator operates the work machine 10 in accordance with the guidance. As a result, the work machine 10 operates in accordance with the target operation.

[0030] Also, for example, the work machine 10 may be operated by a machine control (MC) system. Specifically, a target operation is set in the controller 30. Then, for example, the worker operates only some of the elements of the attachment 15 (for example, only the boom 15a). At this time, the controller 30 (operation control section 33 (see FIG. 2)) automatically controls the elements not operated by the worker (for example, the arm 15b and the bucket 15c) so that the work machine 10 works in accordance with the target operation. At this time, the controller 30 controls the operation of the work machine 10 based on the detection value of the attitude sensor 21 (the same applies in the case of automatic operation). As a result, the work machine 10 operates in accordance with the target operation.

[0031] Also, for example, the work machine 10 may operate by automatic driving. In this case, the controller 30 (operation control section 33) controls the operation of the work machine 10 so that the work machine 10 automatically works in accordance with a target operation. The following mainly describes the case where the work machine 10 operates by automatic control (machine control or automatic driving).

[0032] (Target Action) A target motion of the work machine 10 is set in the controller 30 (more specifically, the target motion setting unit 31). The target motion is a target motion of the work machine 10. The target motion includes a target motion of an excavation motion with the bucket 15c. The target motion may include a target motion of the work machine 10 other than an excavation motion. The target motion may be set (manually) in response to an operation by an operator. The target motion may be automatically generated by the controller 30, or may be set in advance in the controller 30. The target motion may be set in advance outside the controller 30, and input and set in the controller 30. The target motion includes a target path P and a target bucket ground angle θ.

[0033] The target path P is a path that is a target of the bucket 15c. More specifically, the target path P is a path that is a target of the bucket specific part 15c7. The target path P includes a plurality of target points Pp. The target points Pp are information on the target positions of the bucket specific part 15c7. This "position information" is specifically three-dimensional position coordinates. The target path P is an ordered set of the target points Pp. The target path P is information that includes information on the positions of the target points Pp and information on the order of the plurality of target points Pp. Time information may be added to the information on the target path P. Information in which time information is added to the information on the target path P is called a target trajectory. The above "time information" is, for example, a time between two points. The time between two points is a target value of the movement time of the bucket specific part 15c7 between two adjacent (sequential) target points Pp. The time between two points is the time it takes for the bucket specific part 15c7 to arrive from a certain target point Pp to the next target point Pp. The "time information" may be information on the time of day, etc. By adjusting the "time information", the target moving speed of the bucket 15c (specifically, the bucket specific portion 15c7) is adjusted.

[0034] The coordinate axes representing the target path P may be set in any manner as long as they are coordinate axes from which the attitude of the work machine 10 can be derived. The origin (reference position) of this coordinate axis may be set at the work site. The origin of this coordinate axis may be set at a specific portion of the work machine 10, for example, at a specific portion of the upper rotating body 13. Specifically, for example, the origin of this coordinate axis may be set at a mounting portion (boom foot) of the boom 15a to the upper rotating body 13, or may be set at the center of rotation of the upper rotating body 13 relative to the lower traveling body 11. This coordinate axis may include, for example, the front-rear direction X, the up-down direction Z, and the rotation direction of the upper rotating body 13 relative to the lower traveling body 11. This coordinate axis may include, for example, a bucket angle. This bucket angle may be the angle of the bucket 15c relative to the horizontal direction, the angle relative to the arm 15b, or the angle relative to the upper rotating body 13. The controller 30 (more specifically, the operation control unit 33 (see FIG. 2)) determines the attitude of the work machine 10 so that the bucket specific part 15c7 is located on the target path P. For example, once the position of the bucket specific part 15c7 and the bucket angle are determined, the respective attitudes of the boom 15a and the arm 15b are uniquely determined (can be derived).

[0035] The target path P includes a target path of the bucket specific part 15c7 in the excavation operation of the bucket 15c. The target path P may include a target path of the bucket specific part 15c7 in an operation of the work machine 10 that is different from the excavation operation of the bucket 15c. The target path P for the excavation operation of the bucket 15c will be described below. Parameters of the target path P include a target excavation start position Ps, a target excavation end position Pe, a target horizontal excavation distance Lh, and a target excavation depth Ld.

[0036] The target excavation start position Ps is a target position where an excavation operation by the bucket 15c (more specifically, one excavation operation (same below)) starts. For example, the target excavation start position Ps is a target position where the bucket 15c (e.g., the bucket tip 15c5) first comes into contact with a work target in one excavation operation. For example, the target excavation start position Ps is a point (target excavation start point) in three-dimensional coordinates.

[0037] The target excavation end position Pe is a target position where the excavation operation by the bucket 15c ends. For example, the target excavation end position Pe is a target position where the bucket 15c leaves the work target object in one excavation operation. For example, the target excavation end position Pe is a point (target excavation end point) in three-dimensional coordinates.

[0038] The target horizontal excavation distance Lh is a target value of the horizontal movement distance of the bucket 15c during the excavation operation by the bucket 15c. For example, in the example shown in Fig. 1, the target horizontal excavation distance Lh is a target value of the movement distance of the bucket specific part 15c7 when the bucket 15c linearly excavates the work object in the horizontal direction. Also, for example, the target horizontal excavation distance Lh may be a target value of the horizontal distance from the target excavation start position Ps to the target excavation end position Pe (not shown).

[0039] The target excavation depth Ld is a target value of the excavation depth (excavation distance in the vertical direction) of the bucket 15c during an excavation operation by the bucket 15c. For example, the target excavation depth Ld is a target value of the distance in the vertical direction from the height of the bucket tip 15c5 when the bucket tip 15c5 is placed at the deepest position in one excavation operation to a certain reference height. This "reference height" may be, for example, the height of the bottom surface (of the lower traveling body 11) of the machine body 10a. This "reference height" may be, for example, the height of the surface of the work object at the target position where the bucket 15c is going to perform the excavation operation before the bucket 15c performs the excavation operation.

[0040] The target bucket ground angle θ is a target angle (target value) of the ground angle (above) of the bucket 15c. In the example shown in Fig. 1, the target bucket ground angle θ is the angle of the bucket opening surface 15c1 with respect to the horizontal direction. The target bucket ground angle θ includes an excavation start target bucket ground angle θs.

[0041] The excavation start target bucket ground angle θs is the target bucket ground angle θ at the target excavation start position Ps. In detail, the excavation start target bucket ground angle θs is the target bucket ground angle θ when the bucket specific part 15c7 is placed at the target excavation start position Ps.

[0042] (Floating state) As shown in Figures 3 and 5, the machine body 10a may become in a floating state while the work machine 10 is working (for example, during excavation work, etc.). The floating state is a state in which the machine body 10a (more specifically, the lower traveling body 11) is floating above the ground surface (vehicle body floating). The floating state includes a front floating state shown in Figure 3 and a rear floating state shown in Figure 5.

[0043] As shown in FIG. 3, the front-floating state is a state in which the front X1 portion of the bottom surface of the machine body 10a is floating above the ground surface (forward tilt). Examples of causes of the machine body 10a becoming in the front-floating state are as follows. The work machine 10 attempts to move the bucket 15c to the lower side Z2 at the start or during an excavation operation. At this time, the bucket 15c pushes the work object toward the lower side Z2 and receives a reaction force F from the work object toward the upper side Z1. As a result, the front X1 portion of the bottom surface of the machine body 10a floats above the ground surface (i.e., the machine becomes in the front-floating state). The front-floating state is likely to occur when the work object (e.g., the ground) excavated by the bucket 15c is hard. The front-floating state is also likely to occur when the ground angle of the bucket 15c is large (details will be described later).

[0044] As shown in FIG. 5, the rear-floating state is a state in which the rear side X2 portion of the bottom surface of the machine body 10a is floating (rearward tilting) with respect to the ground surface. Examples of causes of the machine body 10a becoming in the rear-floating state are as follows. In the latter half of the excavation operation, the work machine 10 attempts to move (lift) the bucket 15c from a state in which the bucket 15c is buried in the work object to the upper side Z1. At this time, the bucket 15c pushes the work object to the upper side Z1 and receives a reaction force F from the work object to the lower side Z2. As a result, the rear side X2 portion of the bottom surface of the machine body 10a floats with respect to the ground surface (i.e., the rear-floating state occurs). The rear-floating state is likely to occur when the work object (e.g., the ground) excavated by the bucket 15c is hard. In addition, the rear-floating state is likely to occur when the amount of work object is large in the latter half of the target path P (the portion closer to the upper rotating body 13) (see FIG. 10).

[0045] (Determining floating state) The controller 30 shown in FIG. 1 judges whether the machine body 10a is in a floating state based on the inclination (tilt angle) of the machine body 10a. The inclination of the machine body 10a is detected by the inclination detection device 21b and acquired by the controller 30. A specific example of this judgment is as follows. The controller 30 acquires an "initial inclination angle", which is the inclination angle (specifically, pitch angle) of the machine body 10a detected by the inclination detection device 21b when the machine body 10a is not in a floating state (for example, before work). The controller 30 acquires an "inclination angle during work", which is the inclination angle (specifically, pitch angle) of the machine body 10a detected by the inclination detection device 21b when the work machine 10 is working (for example, excavation operation). Then, the controller 30 judges whether the machine body 10a is in a floating state based on the difference between the inclination angle during work and the initial inclination angle (amount of change in the inclination angle). Specifically, the controller 30 judges whether the machine body 10a is in a floating state based on whether the amount of change in the inclination angle exceeds a predetermined threshold (tilt threshold). The controller 30 determines whether the state is a front lift state or a rear lift state depending on whether the amount of change in the tilt angle is a positive value or a negative value.

[0046] (Target action change processing) When the machine body 10a is in a floating state, the controller 30 may perform a target motion change process. The target motion change process is outlined as follows.

[0047] When a target motion change condition (described later) is satisfied, the controller 30 performs a target motion change process. The target motion change process is a process for changing a target motion (e.g., a target path P, an excavation start target bucket ground angle θs, etc.) to a side where the inclination of the machine body 10a becomes smaller. The "side where the inclination of the machine body 10a becomes smaller" is the side where the inclination (inclination angle during work) of the machine body 10a detected by the inclination detection device 21b becomes smaller, and the side where the floating state of the machine body 10a is reduced.

[0048] The target motion change condition is a condition under which the target motion change process is performed. The target motion change condition is set in advance (before the target motion change process is performed) in the controller 30. The target motion change condition includes at least the machine body 10a being in a floating state. The target motion change condition may include the machine body 10a being in a floating state and a condition other than the machine body 10a being in a floating state. For example, the target motion change condition may include a floating state bucket height condition (described later) and the like.

[0049] By carrying out the target motion change process, the floating state of the machine body 10a is suppressed. As a result, vibrations and noises when the machine body 10a is brought down from the floating state to the ground are suppressed, and the machine body 10a is prevented from falling over. Furthermore, the controller 30 automatically changes the target motion to suppress the floating state of the machine body 10a. Therefore, the operator does not need to manually change the target motion.

[0050] The controller 30 can change the target motion in the target motion change process (hereinafter, simply referred to as "changing the target motion") at various times and in various ways. The change of the target motion may include changing the target motion to suppress a front floating state and changing the target motion to suppress a rear floating state. The change of the target motion may include changing the target motion for an excavation motion and changing the target motion for a motion other than an excavation motion. The change of the target motion for an excavation motion may include changing the target motion during the current excavation motion and changing the target motion for the next or subsequent excavation motion. The change of the target motion for an excavation motion may include examples A to E, which will be described later. Details of each example will be described below.

[0051] (Timing of change in target behavior) The controller 30 may change the target motion at various times.

[0052] (Change of target action during current excavation action) If a target motion change condition is satisfied while bucket 15c is performing the "current excavation operation", controller 30 may change the target motion in the "current excavation operation". A specific example of this example is as follows. Controller 30 causes bucket 15c to perform an excavation operation ("current excavation operation") based on the target motion before the change. During this excavation operation, machine body 10a becomes in a floating state. At this time, controller 30 changes the target motion for this "current excavation operation". Then, controller 30 causes bucket 15c to perform an excavation operation based on the changed target motion from the middle of the "current excavation operation".

[0053] (Change of target operation during next excavation operation) If the target motion change condition is satisfied while the bucket 15c is performing the "current excavation operation", the controller 30 may change the target motion for the "next or subsequent excavation operation". The "next or subsequent excavation operation" may be only one excavation operation from the next or subsequent (for example, the next) or multiple excavation operations from the next or subsequent. A specific example of this example is as follows. The controller 30 causes the bucket 15c to perform an excavation operation (the "current excavation operation") based on the target motion before the change. During this excavation operation, the machine body 10a becomes in a floating state. At this time, the controller 30 changes the target motion for the next or subsequent excavation operation. Then, the controller 30 causes the bucket 15c to perform an excavation operation based on the changed target motion in the next or subsequent excavation operation.

[0054] (Changes in target actions at other times) The controller 30 may change a target motion other than the excavation motion of the bucket 15c when a target motion change condition is satisfied when the bucket 15c is not performing an excavation operation (e.g., after completion of an excavation operation, before starting an excavation operation) (specific examples will be described later).

[0055] (Changes to target behavior) Changes to the target motion of the excavation operation may include changes to the target path P (example A) (see Figs. 4 and 6) and changes to the excavation start target bucket ground angle θs (example B) (see Fig. 4). Changes to the target motion of the excavation operation may include changes to the motion direction (reverse playback) (example C) (see Fig. 14), restrictions on the elements of the attachment 15 to be operated (example D) (see Fig. 15), and changes to a discharge motion (example E) (see Fig. 16).

[0056] (Example A: Change of target route P) The controller 30 shown in FIG. 1 may change the target path P as a change in the target operation. This "change in the target path P" is a change in the target path P to a side where the inclination of the machine body 10a becomes smaller. Specifically, the change in the target path P is a change in the parameters of the target path P. The change in the target path P includes a change in the target path P for suppressing a front lifting state (see FIG. 4) and a change in the target path P for suppressing a rear lifting state (see FIG. 6). The controller 30 will be described below with reference to FIG. 1.

[0057] (Example A1: Changing the target path P to suppress the front floating state) As shown in FIG. 3, the machine body 10a may be in a front-floating state because the force of the bucket 15c pushing the work object toward the lower side Z2 is too large, and the reaction force F on the upper side Z1 that the bucket 15c receives from the work object is too large. Therefore, the controller 30 performs the following process when a "front-floating state handling condition" (one example of a target operation change condition) including the machine body 10a being in a front-floating state is satisfied. In this case, as shown in FIG. 4, the controller 30 changes the target path P so that the force of the bucket 15c pushing the work object toward the lower side Z2 (downward) is reduced. Specifically, the controller 30 changes the target excavation depth Ld so that the force of the bucket 15c pushing the work object toward the lower side Z2 is reduced. Specifically, the controller 30 makes the target excavation depth Ld shallower. In FIG. 4, the target path P before the change is indicated by a two-dot chain line, and the target path P after the change is indicated by a solid line.

[0058] (Example A2: Changing the target path P to suppress rear lift) As shown in FIG. 5, the machine body 10a may be in a rear-floating state because the force of the bucket 15c lifting the work object to the upper side Z1 is too large, and the reaction force F of the lower traveling body 11 that the bucket 15c receives from the work object is too large. Therefore, the controller 30 performs the following process when the "rear-floating state handling condition" (one example of the target operation change condition) including the machine body 10a being in the rear-floating state is satisfied. In this case, as shown in FIG. 6, the controller 30 changes the target path P so that the force of the bucket 15c pushing the work object to the upper side Z1 (upward) becomes smaller. Specifically, the controller 30 may change the target excavation depth Ld (example A2-1), may change the target horizontal excavation distance Lh (example A2-2), may change the target excavation end position Pe (example A2-3), or may perform these changes in combination.

[0059] (Example A2-1) The controller 30 may change the target excavation depth Ld when the post-floating state handling condition is satisfied. In this case, the controller 30 changes the target excavation depth Ld so as to reduce the amount of the work object (e.g., the amount of soil) lifted by the bucket 15c. Specifically, the controller 30 makes the target excavation depth Ld shallower.

[0060] (Example A2-2) The controller 30 may change the target horizontal excavation distance Lh when the post-floating state handling condition is satisfied. In this case, the controller 30 changes the target horizontal excavation distance Lh so as to reduce the amount of the work object (e.g., soil volume) lifted by the bucket 15c. Specifically, the controller 30 shortens the target horizontal excavation distance Lh.

[0061] (Example A2-3) The controller 30 may change the target excavation end position Pe when the rear floating state handling condition is satisfied. In this case, the controller 30 changes the target excavation end position Pe so as to reduce the amount of the work object (e.g., the amount of soil) lifted by the bucket 15c. Specifically, the controller 30 changes the target excavation end position Pe to the front side X1.

[0062] The reason for changing the target excavation end position Pe to the front side X1 is as follows. The bucket 15c excavates the work object from the front side X1 to the rear side X2. Therefore, the work object is likely to accumulate in the vicinity of the rear side X2 part of the target path P (the part on the front side as seen from the machine body 10a) (see FIG. 10). Therefore, when the bucket 15c tries to lift a large amount of work objects that have accumulated on the front side as seen from the machine body 10a, the machine body 10a is likely to be in a rear floating state. Therefore, when the rear floating state handling condition is satisfied, the controller 30 changes the target excavation end position Pe (the position where the bucket 15c scoops up the work object) to the front side X1. Therefore, the possibility that the bucket 15c will lift the work object that has accumulated on the front side as seen from the machine body 10a is reduced. Therefore, the amount of the work object that the bucket 15c lifts (e.g., the amount of soil) is reduced. Therefore, the rear floating state of the machine body 10a is suppressed. In addition, as a result of changing the target excavation end position Pe to the front side X1, the target horizontal excavation distance Lh may be shortened. As a result of shortening the target horizontal excavation distance Lh, the amount of work object lifted by the bucket 15c may be reduced.

[0063] (Example B: Changing the digging start target bucket ground angle θs) The controller 30 may change the target bucket ground angle θs for starting excavation as a change in the target operation. Here, as shown in FIG. 3, the cause of the machine body 10a being in a front-floating state may be that the ground angle of the bucket 15c (angle corresponding to the target bucket ground angle θs for starting excavation) is too large at the target excavation start position Ps. If the ground angle of the bucket 15c is too large at the target excavation start position Ps, the force with which the bucket tip back surface 15c3 pushes the work object downward Z2 increases when the bucket tip 15c5 is inserted (penetrated) into the work object. Therefore, the reaction force F (resistance) that the bucket 15c receives from the work object increases, making it difficult for the bucket tip 15c5 to be inserted into the work object. As a result, the machine body 10a is in a front-floating state.

[0064] Therefore, as shown in FIG. 4, when the front floating state handling condition is satisfied, the controller 30 changes the excavation start target bucket ground angle θs so that the force with which the bucket 15c pushes the work object downward Z2 (downward) is reduced. In this case, the controller 30 changes the excavation start target bucket ground angle θs so that the reaction force F that the bucket 15c receives when the bucket tip 15c5 is inserted into the work object is reduced. Specifically, in the example shown in FIG. 4, the controller 30 reduces (shallows) the excavation start target bucket ground angle θs. In FIG. 4, the excavation start target bucket ground angle θs and the bucket 15c before the change are shown by two-dot chain lines, and the excavation start target bucket ground angle θs and the bucket 15c after the change are shown by solid lines. When the front floating state handling condition is satisfied, the controller 30 may both change the target path P in the above example A1 and change the excavation start target bucket ground angle θs. Depending on the definition of the excavation start target bucket ground angle θs, increasing the excavation start target bucket ground angle θs may reduce the force with which bucket 15c pushes the work object downward Z2 (downward).

[0065] (Physical limitations of attachment 15 posture) As shown in FIG. 7, when the excavation start target bucket ground angle θs cannot be changed to the smaller side (shallower side) due to the structure of the work machine 10, the controller 30 changes the target excavation start position Ps as shown in FIG.

[0066] The reason for changing the target excavation start position Ps is as follows. As shown in Fig. 7, the structure of the work machine 10 limits the range of possible attitudes of the attachment 15. Specifically, the structure of the work machine 10 limits the range of possible angles of the bucket 15c relative to the arm 15b (bucket rotation angle φ). For example, the range of possible bucket rotation angles φ is limited between the state in which the bucket cylinder 17c is most retracted (or substantially most retracted) and the state in which the bucket cylinder 17c is most extended (or substantially most extended). Therefore, even if an attempt is made to make the excavation start target bucket ground angle θs smaller (shallower) when the front floating state handling condition is satisfied, the bucket rotation angle φ corresponding to the excavation start target bucket ground angle θs may be an angle that cannot be taken due to the structure of the work machine 10. For example, when the excavation position of the work object by the bucket 15c is low (deep) relative to the bottom of the machine body 10a, the bucket rotation angle φ corresponding to the target bucket ground angle θs for starting excavation is likely to be an angle that cannot be taken due to the structure of the work machine 10. Therefore, when the ground angle of the bucket 15c cannot be changed to a smaller angle due to the structure of the work machine 10, the controller 30 changes the target excavation start position Ps as shown in Fig. 8. Specifically, the controller 30 changes the target excavation start position Ps to the front side X1.

[0067] The process of changing the target excavation start position Ps will be described with reference to the flowchart shown in Fig. 9. Each step (S11 to S15) will be described below with reference to Fig. 9. Unless otherwise specified, each process will be described in the order of the process shown in the flowchart (the same applies to flowcharts other than Fig. 9). Note that the order of each process can be changed in various ways.

[0068] In step S11, the controller 30 determines a changed excavation start target bucket ground angle θs when the machine body 10a is in a front floating state and the front floating state handling condition is satisfied as shown in FIG.

[0069] In step S12, the controller 30 calculates a candidate value of the bucket rotation angle φ corresponding to the determined excavation start target bucket ground angle θs. This candidate value of the bucket rotation angle φ is the bucket rotation angle φ when it is assumed that the ground angle of the bucket 15c is set to the determined excavation start target bucket ground angle θs without changing the target excavation start position Ps.

[0070] In step S13, the controller 30 determines whether the calculated candidate value for the bucket rotation angle φ is within the bucket rotation angle allowable range. The bucket rotation angle allowable range is a permissible range of the bucket rotation angle φ, and is set in advance (before this determination) in the controller 30. The bucket rotation angle allowable range is a range of the bucket rotation angle φ that can be obtained due to the structure of the work machine 10. Note that in FIG. 9, the "bucket rotation angle allowable range" is simply described as an "allowable range." If the calculated candidate value for the bucket rotation angle φ is within the bucket rotation angle allowable range (YES in step S13), the controller 30 advances the process flow to step S14. If the calculated candidate value for the bucket rotation angle φ is not within the bucket rotation angle allowable range (NO in step S13), the controller 30 advances the process flow to step S15.

[0071] In step S14, the controller 30 does not perform the process (step S15) of changing the target excavation start position Ps shown in Fig. 7. In this case, the controller 30 controls the bucket 15c so that the ground angle of the bucket 15c at the target excavation start position Ps becomes the excavation start target bucket ground angle θs in the next and subsequent excavation operations.

[0072] In step S15, the controller 30 changes the target excavation start position Ps to the front side X1 (the rear side as viewed from the machine body 10a) as shown in Fig. 8. At this time, the controller 30 changes the target excavation start position Ps so that the ground angle of the bucket 15c becomes the excavation start target bucket ground angle θs after the change determined in step S11 and the bucket rotation angle φ falls within the bucket rotation angle allowable range. This process allows the ground angle of the bucket 15c to become the excavation start target bucket ground angle θs after the change determined in step S11. As a result, the front floating state of the machine body 10a (see Fig. 7) can be suppressed.

[0073] (Change in target movement) The controller 30 may change the amount of change in the target motion (the amount of change in the change in the target motion in the target motion change process) depending on the conditions. The controller 30 may change the amount of change in the target path P shown in FIG. 4 depending on the conditions. The controller 30 may change the amount of change in the excavation start target bucket ground angle θs depending on the conditions. For example, the controller 30 may change the amount of change in the target motion depending on the bucket height H15c (see FIG. 10) during the excavation operation, or depending on the inclination of the machine body 10a. The controller 30 may accumulate the amount of change in the target motion. Details of each example are as follows.

[0074] (Change amount according to bucket height H15c) The controller 30 may change the amount of change in the target motion according to the bucket height H15c (depth, height of the attachment 15) when the bucket 15c shown in FIG. 10 is performing an excavation motion (during an excavation motion). The bucket height H15c is the position of the bucket 15c in the height direction. The bucket height H15c is, for example, the distance in the height direction from a reference position of the machine body 10a (for example, the base end of the boom 15a or the bottom surface of the lower traveling body 11) to the bucket specific part 15c7. The above-mentioned "height direction" may be the vertical direction or the up-down direction Z based on the machine body 10a. The controller 30 may change the amount of change in the target path P or the amount of change in the excavation start target bucket ground angle θs according to the bucket height H15c during an excavation motion.

[0075] The reason for changing the change amount of the target operation according to the bucket height H15c during the excavation operation is as follows. When the bucket height H15c is large (the excavation position is deep), the reaction force F (see Figs. 3 and 5) acting on the bucket 15c is likely to be larger than when the bucket height H15c is small (the excavation position is shallow). For example, a work object that is deep from the surface (ground) of the work object before excavation is often harder than a work object that is shallow. Therefore, when the bucket 15c is inserted into the work object, the reaction force F (see Fig. 3) acting on the bucket 15c is likely to be larger when the bucket height H15c is large than when it is small. Also, when the bucket 15c excavates so as to lift the work object, the amount of the work object (e.g., the amount of soil) lifted by the bucket 15c is larger when the bucket height H15c is large than when the bucket height H15c is small. Therefore, when bucket 15c excavates so as to lift up a work object, reaction force F (see FIG. 5) acting on bucket 15c is likely to be larger when bucket height H15c is large than when it is small.

[0076] In this way, when the bucket height H15c is large, the reaction force F (see Figs. 3 and 5) acting on the bucket 15c is more likely to be large than when it is small, and the machine body 10a is more likely to be in a floating state. Therefore, when the bucket height H15c is large, it is more necessary to change the target operation than when it is small.

[0077] On the other hand, the reaction force F (see FIGS. 3 and 5) acting on the bucket 15c is more likely to be smaller when the bucket height H15c is small than when it is large. Therefore, there is less need to change the target operation when the bucket height H15c is small than when it is large. If the target operation is changed too much to reduce the inclination of the machine body 10a when the bucket height H15c is small, the amount of the work object excavated by the bucket 15c will decrease, and the workability of the work machine 10 will deteriorate.

[0078] Therefore, the controller 30 changes the amount of change in the target operation according to the bucket height H15c during excavation operation. A specific example of this process is as follows. When the bucket 15c is performing excavation work, the machine body 10a becomes floating. At this time, the controller 30 stores the "floating state bucket height." The "floating state bucket height" is the bucket height H15c when the machine body 10a becomes floating.

[0079] After the machine body 10a becomes floating and the "floating state bucket height" is stored in the controller 30, the bucket 15c performs excavation operation at another position (an excavation position different in the forward / backward direction X or rotation direction from the excavation position when the machine body 10a became floating). At that time, the bucket 15c may perform excavation operation at a position higher than the floating state bucket height (or a height close to the floating state bucket height (same below)). When the bucket 15c performs excavation operation at a position higher than the floating state bucket height, it is expected that the machine body 10a is less likely to become floating than when the bucket 15c performs excavation operation at a position lower than the floating state bucket height.

[0080] Therefore, the controller 30 restricts the change of the target operation when the bucket 15c performs an excavation operation at a position above a "height threshold" based on the floating bucket height. The "height threshold" may be the same height as the floating bucket height. The height threshold may be a height different from the floating bucket height that is set based on the floating bucket height. The height threshold may be, for example, a height in the vicinity of the floating bucket height. The "position above" the height threshold may be a position vertically above the height threshold, or may be a position above the height threshold Z1 based on the upper rotating body 13.

[0081] Controller 30 reduces (i.e., limits) the amount of change in the target motion when bucket 15c performs an excavation operation at a position above the height threshold compared to the amount of change in the target motion when bucket 15c performs an excavation operation at a height equal to or less than the height threshold. Controller 30 does not need to change the target motion when bucket 15c performs an excavation operation at a position above the height threshold. In other words, the above-mentioned "limitation" of the target motion change process may include setting the amount of change in the target motion when bucket 15c performs an excavation operation at a position above the height threshold to zero.

[0082] By limiting the change in the target motion when the bucket 15c performs an excavation operation at a position above the height threshold, the excavation amount (e.g., soil volume) of the work object can be stably ensured. Also, the change in the target motion when the bucket 15c performs an excavation operation at a position below the height threshold may be greater than the change in the target motion when the bucket 15c performs an excavation operation at a position above the height threshold. In this case, the target motion is changed more to the side where the inclination of the machine body 10a is reduced, so that the machine body 10a is prevented from floating.

[0083] (Amount of change according to the inclination of the machine body 10a) The controller 30 may change the amount of change in the target motion according to the inclination (amount of inclination, angle of inclination) of the machine body 10a detected by the inclination detection device 21b shown in FIG. 1 (see FIG. 11).

[0084] The reason for changing the amount of change in the target motion in response to the inclination of the machine body 10a is as follows. As described above, the controller 30 changes the target motion to the side where the reaction force F (see Figs. 3 and 5) acting on the bucket 15c is reduced by the target motion change process (see Figs. 4 and 6). This may result in the target motion being changed to the side where the amount of excavation of the work object by the bucket 15c is reduced. Therefore, if the amount of change in the target motion is made too large, the amount of excavation of the work object by the bucket 15c may be reduced too much. On the other hand, if the amount of change in the target motion is too small, the machine body 10a may again become floating. Therefore, the controller 30 changes the amount of change in the target motion in response to the inclination of the machine body 10a.

[0085] The controller 30 may change the amount of change in the target motion according to the in-work tilt angle (absolute value of the tilt angle) of the machine body 10a. The controller 30 may change the amount of change in the target motion according to the difference between the in-work tilt angle of the machine body 10a and the initial tilt angle (relative value of the tilt angle, amount of lift). The controller 30 increases the amount of change in the target motion as the tilt angle increases. The controller 30 may change the amount of change in the target motion stepwise (two or more steps) or continuously as the tilt of the machine body 10a increases (see FIG. 11). The relationship between the amount of change in the target motion and the tilt of the machine body 10a may include, for example, a linear function, or may include, for example, a proportional relationship (see FIG. 11).

[0086] (Accumulation of change in target behavior) The controller 30 may change the target motion multiple times. In this case, the controller 30 may accumulate the amount of change in the target motion (see FIG. 12).

[0087] A specific example of the accumulation of the change amount of the target motion (see FIG. 12) is as follows. When the machine body 10a is in a floating state and the target motion change condition is satisfied, the controller 30 changes the target motion. This change is set as an "initial change". The change amount of the target motion in the initial change is set as an "initial change amount". The controller 30 causes the bucket 15c to perform an excavation operation in the target motion (changed target motion) in which the "initial change" has been performed. Then, when the bucket 15c performs an excavation operation in the changed target motion, the machine body 10a may again be in a floating state. In this case, the controller 30 further changes the target motion to the side where the inclination of the machine body 10a becomes smaller. This change of the target motion is set as an "additional change". The change amount of the target motion in the additional change is set as an "additional change amount". The controller 30 may change the additional change amount according to the bucket height H15c. The controller 30 may change the additional change amount according to the inclination of the machine body 10a.

[0088] The controller 30 sets the sum of the initial change amount and the additional change amount as the accumulated change amount. The controller 30 changes the target motion based on this accumulated change amount. The controller 30 may perform additional changes multiple times. When the controller 30 performs additional changes multiple times, the controller 30 sets the sum of the initial change amount and the accumulated value of the additional change amounts as the accumulated change amount.

[0089] Further specific examples of the accumulation of the change amount of the target operation are as follows. Here, a case where the target excavation depth Ld is changed as a change of the target operation will be described. When the bucket 15c is performing an excavation operation, the machine body 10a becomes in a floating state (first time). At this time, the controller 30 changes the target excavation depth Ld for the next or current excavation operation to be shallower by the initial change amount, as shown in FIG. 4. The controller 30 also changes the target excavation depth Ld for the subsequent excavation operation to be shallower by the initial change amount. When the bucket 15c performs an excavation operation at the target excavation depth Ld that has been changed to be shallower by the initial change amount, the machine body 10a becomes in a floating state (second time) again. At this time, the controller 30 changes the target excavation depth Ld for the next or current excavation operation to be shallower by the sum of the initial change amount and the additional change amount (accumulated change amount). When the machine body 10a becomes in a floating state from the third time onwards, the controller 30 further adds the additional change amount to the accumulated change amount (see FIG. 12). In this example, the case where the change amount of the target excavation depth Ld is accumulated is described, but the change amounts of the target horizontal excavation distance Lh, the target excavation end position Pe, the target bucket ground angle θs for the start of excavation, etc. may also be accumulated in a similar manner.

[0090] (Limits on accumulated change amount) If the integrated change amount becomes too large, the amount of the work object excavated by the bucket 15c will decrease. Therefore, the controller 30 limits the change in the target motion so that the integrated change amount is equal to or less than the integrated change amount limit value (see FIG. 12). The integrated change amount limit value is set in advance in the controller 30 (before limiting the change amount of the target motion). As a result of limiting the integrated change amount to or less than the integrated change amount limit value, the amount of the work object excavated by the bucket 15c is ensured.

[0091] A specific example of limiting the integrated change amount will be described with reference to the flowchart shown in Fig. 13. Steps S21 to S24 will be described below with reference to Fig. 13.

[0092] In step S21, the controller 30 shown in Fig. 1 calculates a candidate value for the integrated change amount. In detail, when the machine body 10a is in a floating state, the controller 30 calculates a candidate value for the "current change amount." This "current change amount" is the change amount of the target operation in the current process (corresponding to the current floating state), and is an initial change amount or an additional change amount. Then, the controller 30 calculates the sum of the integrated change amount up to the previous time and the current change amount as the candidate value for the integrated change amount.

[0093] In step S22, the controller 30 determines whether the candidate value for the integrated change amount is equal to or greater than the integrated change amount limit value. The integrated change amount limit value is set in advance (before this determination) in the controller 30. If the candidate value for the integrated change amount is equal to or greater than the integrated change amount limit value (YES in step S22), the controller 30 advances the process flow to step S23. If the candidate value for the integrated change amount is less than the integrated change amount limit value (NO in step S22), the controller 30 sets the candidate value for the integrated change amount as the determined value for the integrated change amount, and advances the process flow to step S24.

[0094] In step S23, if the candidate value for the integrated change amount is equal to or greater than the integrated change amount limit value (YES in step S22), the controller 30 corrects (sets) the determined value of the integrated change amount to be equal to or less than the integrated change amount limit value (see FIG. 12). In this case, the controller 30 may set the determined value of the integrated change amount to a value equal to the integrated change amount limit value or a value less than the integrated change amount limit value. Next, the controller 30 advances the process flow to step S24.

[0095] In step S24, the controller 30 stores the determined value of the integrated change amount, and then changes the target motion based on the determined value of the integrated change amount.

[0096] (Example C: Changing the direction of motion (reverse playback)) As shown in Fig. 14, the controller 30 may change the movement direction of the attachment 15 as a change in the target movement. Specifically, the controller 30 may change the target movement so as to perform reverse playback of the target path P when a reverse playback execution condition (described later) (one example of a target movement change condition) is satisfied. Note that in Fig. 14, the work machine 10 before reverse playback is performed is indicated by a two-dot chain line, and the work machine 10 after reverse playback is performed is indicated by a solid line.

[0097] The reason for changing the target motion to change the motion direction of the attachment 15 is as follows. One of the causes of the floating state of the machine body 10a is that when the bucket 15c performs an excavation motion along the target path P, a reaction force F (see Figs. 3 and 5) acts on the bucket 15c from the work target. Therefore, the controller 30 changes the motion direction of the attachment 15. Specifically, the controller 30 performs reverse playback of the target path P. "Reverse playback" means moving (operating) the attachment 15 in a direction opposite (returning direction) to the direction of movement of the attachment 15 in the excavation motion along the target path P. In reverse playback, the controller 30 moves (operates) the bucket 15c in a direction opposite (returning direction) to the direction of movement of the bucket 15c in the excavation motion along the target path P. In reverse playback, the controller 30 moves the bucket 15c so as to trace the past trajectory of the bucket 15c in the excavation motion along the target path P.

[0098] In the example shown in FIG. 1, in a normal excavation operation, the bucket 15c performs, for example, a digging operation, a horizontal excavation operation, and a lifting operation. In the digging operation, the bucket 15c digs down the work object on the lower side Z2 and the rear side X2. In the horizontal excavation operation, the bucket 15c excavates the work object on the rear side X2. In the lifting operation, the bucket 15c lifts (digs up) the work object while excavating it on the upper side Z1 and the rear side X2. If the normal excavation operation is such an operation, in the reverse playback of the lifting operation, the bucket 15c moves to the lower side Z2 and the front side X1. In the reverse playback of the horizontal excavation operation, the bucket 15c moves to the front side X1. In the reverse playback of the excavation operation, the bucket 15c moves to the front side X1 and the upper side Z1. Note that, although FIG. 14 illustrates a case where reverse playback is performed when the machine body 10a is in a front floating state, reverse playback may also be performed when the machine body 10a is in a rear floating state.

[0099] (Conditions for reverse playback) As described above, the controller 30 may perform reverse playback of the target path P when the reverse playback execution condition (one example of the target motion change condition) is satisfied. The reverse playback execution condition can be set in various ways. The reverse playback execution condition includes at least that the machine body 10a is in a floating state. The reverse playback execution condition may include that the machine body 10a is in a floating state and the inclination of the machine body 10a detected by the inclination detection device 21b is a specific inclination state (a specific state other than the floating state). The above-mentioned "specific inclination state" is set in advance in the controller 30 (before determining whether or not the reverse playback execution condition is satisfied). For example, the above-mentioned "specific inclination state" may be a state in which the inclination of the machine body 10a is a specific magnitude, for example, a state in which the inclination exceeds a predetermined threshold (reverse playback execution inclination threshold). The above-mentioned "specific inclination state" may be a state in which the inclination of the machine body 10a increases (worsens). The reverse playback execution condition may include a condition different from the above-mentioned conditions.

[0100] (Example D: Restricting the elements of attachment 15 to be activated) 15, when a motion element limiting condition (an example of a target motion change condition) (described later) is satisfied, the controller 30 may limit the elements of the attachment 15 to be operated as a change in the target motion. The controller 30 may change the target motion so as to limit the elements of the attachment 15 to be operated to a side where the inclination of the machine body 10a becomes smaller.

[0101] The reason for changing the target motion to limit the elements of the attachment 15 to be operated is as follows. For example, when all the elements of the attachment 15 (boom 15a, arm 15b, and bucket 15c) perform an excavation motion, the reaction force F (see Figs. 3 and 5) acting from the work target to the bucket 15c may be large, causing the machine body 10a to float. In this case, if only some of the elements of the attachment 15 (for example, only the bucket 15c) are made to perform the excavation motion, the reaction force F acting from the work target to the bucket 15c is likely to be small, and the floating state of the machine body 10a is likely to be suppressed.

[0102] Therefore, the controller 30 limits the elements of the attachment 15 that perform the excavation operation to only a part of the attachment 15. Specifically, the controller 30 limits the elements of the attachment 15 that perform the excavation operation to only the bucket 15c. More specifically, in the target motion before the change, the controller 30 sets the target motion to perform the excavation operation of the bucket 15c and the elements other than the bucket 15c (one or both of the boom 15a and the arm 15b). Then, in the target motion after the change, the controller 30 sets the target motion to perform the excavation operation of only the bucket 15c among the elements of the attachment 15. Specifically, in the target motion after the change, the controller 30 sets the target motion to stop the boom 15a and the arm 15b and rotate the bucket 15c to the excavation side R1 with respect to the arm 15b. By limiting the elements of the attachment 15 that are excavated by the controller 30 to only a part of the attachment 15 (for example, only the bucket 15c), the reaction force F (see Figs. 3 and 5) acting on the bucket 15c from the work object tends to be small. As a result, the floating state of the machine body 10a tends to be eliminated.

[0103] (Operational element restrictions) As described above, when the motion element limiting condition (one example of the target motion change condition) is satisfied, the controller 30 may limit the elements of the attachment 15 to be operated. The motion element limiting condition can be set in various ways. The motion element limiting condition includes that the machine body 10a is in a floating state. For example, the motion element limiting condition may include that the machine body 10a is in a floating state, and the inclination of the machine body 10a detected by the inclination detection device 21b is in a specific inclination state (a specific state other than the floating state). This "specific inclination state" is set in advance in the controller 30 (before determining whether the motion element limiting condition is satisfied). This "specific inclination state" may include that the magnitude of the inclination of the machine body 10a is a specific magnitude, may include that the machine body 10a is in a rear floating state, or may include that the machine body 10a is in a front floating state.

[0104] (Example E: Change to ejection operation) 16, when a discharge condition (described later) is satisfied, the controller 30 may change the target operation to cause the bucket 15c to perform a discharge operation (for example, adjusting the amount of soil in the bucket 15c). In particular, when a discharge condition is satisfied in a state in which the bucket 15c is not performing a discharge operation, the controller 30 may change the target operation to cause the bucket 15c to perform a discharge operation.

[0105] The reason for changing the target operation to have the bucket 15c perform the discharge operation is as follows. When the work machine 10 is not performing an excavation operation, if the amount of work object in the bucket 15c is too large, the machine body 10a may enter a rear floating state. The above-mentioned "when the work machine 10 is not performing an excavation operation" refers, for example, to after the excavation operation is completed and before the bucket 15c discharges the work object. The above-mentioned "when the work machine 10 is not performing an excavation operation" refers, for example, to when the bucket 15c is moving (lifting) the work object to the upper side Z1. Therefore, the controller 30 changes the target operation to have the bucket 15c perform the discharge operation when the discharge condition is satisfied.

[0106] The above-mentioned "discharge operation" is an operation for discharging a work object from the bucket 15c. Specifically, the discharge operation is an operation including rotation of the bucket 15c to the discharge side R2. When the controller 30 causes the bucket 15c to perform the discharge operation, the amount of work object (e.g., the amount of soil) in the bucket 15c is reduced. As a result, the rear floating state of the machine body 10a is eliminated. In this discharge operation, it is preferable that the work object in the bucket 15c is discharged from the bucket 15c until the rear floating state of the machine body 10a is eliminated. This discharge operation may be ended with the work object remaining in the bucket 15c.

[0107] When discharging the bucket 15c, the controller 30 may operate one or both of the boom 15a and the arm 15b. For example, when discharging the bucket 15c, the controller 30 may move the boom 15a in a direction in which the tip of the boom 15a moves to the upper side Z1 (the controller 30 may perform a lifting operation of the boom 15a).

[0108] (Emission conditions) As described above, the controller 30 may cause the bucket 15c to perform a discharge operation when a discharge condition (an example of a target operation change condition) is satisfied. The discharge condition can be set in various ways. The discharge condition includes that the machine body 10a is in a floating state (more specifically, a rear floating state). The discharge condition may also include that the machine body 10a is in a rear floating state and that an excavation operation is not being performed.

[0109] (Examples of changing target behavior) The above examples of changing the target motion can be combined in various ways. The timing of changing the target motion can be set in various ways, and the contents of the change in the target motion can be set in various ways. Below, specific examples of the target motion changing process of the controller 30 will be described with reference to the flowcharts shown in Figs. 17 to 19. Below, steps S31 to S34 will be described with reference to Fig. 17.

[0110] In step S31, the controller 30 shown in FIG. 1 acquires the inclination of the machine body 10a detected by the inclination detection device 21b.

[0111] In step S32, the controller 30 judges whether the machine body 10a is floating or not from the inclination acquired in step S31. If the machine body 10a is not floating (NO in step S32), the controller 30 returns the process flow to step S31 (start). If the machine body 10a is floating (YES in step S32), the controller 30 advances the flow to step S33.

[0112] In step S33, the controller 30 stores the "floating state bucket height" which is the bucket height H15c (see FIG. 10) when the machine body 10a is in the floating state. In FIG. 9, the floating state bucket height is simply described as the "bucket height."

[0113] In step S34, the controller 30 judges whether the machine body 10a is in a front-floating state from the inclination acquired in step S31. If the machine body 10a is in a front-floating state (YES in step S34), the controller 30 performs processing to deal with the front-floating state in the current excavation operation (step S50). If the machine body 10a is in a rear-floating state (NO in step S34), the controller 30 performs processing to deal with the rear-floating state in the current excavation operation (step S70).

[0114] As shown in Fig. 18, in step S50, when the machine body 10a is in a front-floating state, the controller 30 shown in Fig. 1 performs processing for dealing with the front-floating state in the current excavation operation. Steps S52 to S54 will be described below with reference to Fig. 18.

[0115] In step S52, the controller 30 shown in FIG. 1 judges the inclination state of the machine body 10a. Specifically, the controller 30 judges whether the inclination state of the machine body 10a in the front floating state is a "large inclination state" (simply indicated as "large" in FIG. 18) or not. The large inclination state is set in advance in the controller 30 (before the judgment of whether the machine body 10a is in a large inclination state or not is made). The large inclination state may be, for example, that the difference between the inclination angle during work and the initial inclination angle (relative value of the inclination angle) is equal to or greater than a threshold value, or that the value of the inclination angle during work (absolute value of the inclination angle) is equal to or greater than a threshold value. If the inclination state of the machine body 10a is not a "large inclination state" (NO in step S52), the controller 30 advances the flow to step S52n. If the inclination state of the machine body 10a is a "large inclination state" (YES in step S52), the controller 30 advances the flow to step S53.

[0116] In step S52n, the controller 30 changes the target path P for the current excavation operation. For example, the controller 30 makes the target excavation depth Ld shallower (see example A1 above) (see FIG. 4). Then, the controller 30 ends the process for dealing with the front floating state in the current excavation operation (step S50), and causes the flow to proceed to step S61 (see FIG. 17).

[0117] In step S53, the controller 30 causes the bucket 15c to move in a direction opposite to the movement of the bucket 15c along the target path P in the excavation operation (reverse playback), as shown in FIG. 14 (see example C above).

[0118] In step S54, the controller 30 judges whether the front floating state of the machine body 10a has been resolved. The controller 30 continues the reverse playback of step S53 until the front floating state of the machine body 10a is resolved (until YES is determined in step S54). If the front floating state of the machine body 10a has been resolved (YES in step S54), the controller 30 ends the process for dealing with the front floating state in the current excavation operation (step S50) and causes the flow to proceed to step S61 shown in FIG. 17.

[0119] In step S61, the controller 30 determines whether the bucket height H15c (see FIG. 10) in the next excavation operation is greater (deeper) than the "floating bucket height" stored in step S33. If the bucket height H15c in the next excavation operation is greater than the floating bucket height (YES in step S61), the controller 30 advances the flow to step S62. If the bucket height H15c in the next excavation operation is the same as or smaller (shallower) than the floating bucket height (NO in step S61), the controller 30 ends the current processing flow (proceeds to RETURN). Then, the controller 30 starts the next processing flow (returns to START).

[0120] In step S62, the controller 30 performs processing to deal with the front floating state in the next excavation operation. For example, the controller 30 changes the target path P in the next excavation operation as shown in FIG. 4 (see Example A above). Specifically, the controller 30 decreases the target excavation depth Ld in the next excavation operation (see Example A1 above). Also, for example, the controller 30 changes the excavation start target bucket ground angle θs in the next excavation operation (see Example B above). Then, the controller 30 ends the current processing flow and starts the next processing flow.

[0121] As shown in Fig. 19, in step S70, if the machine body 10a is in a rear-floating state (NO in step S34 in Fig. 17), the controller 30 performs processing to deal with the rear-floating state in the current excavation operation. Steps S71 to S76 shown in Fig. 19 will be described below with reference to Fig. 19.

[0122] In step S71, the controller 30 shown in Fig. 1 determines whether the bucket 15c (the attachment 15) is in an excavation operation. If the bucket 15c is in an excavation operation (YES in step S71), the controller 30 advances the flow to step S72. If the bucket 15c is not in an excavation operation (NO in step S71), the controller 30 advances the flow to step S71n.

[0123] In step S71n, the controller 30 causes the bucket 15c to perform a discharge operation as shown in Fig. 16 (see Example E above). In particular, when the machine body 10a is in a rear-floating state and the bucket 15c is not performing an excavation operation, the controller 30 causes the bucket 15c to perform a discharge operation. At this time, the controller 30 may also cause the boom 15a to perform a lifting operation. Then, the controller 30 ends the process of dealing with the rear-floating state during the current excavation operation (step S70), and causes the flow to proceed to step S81 (see Fig. 17).

[0124] In step S72, the controller 30 judges the inclination state of the machine body 10a. Specifically, the controller 30 judges whether the inclination state of the machine body 10a is a "large inclination state" (simply indicated as "large" in FIG. 19) as in step S52 (see FIG. 18). Note that the "large inclination state" in step S52 (see FIG. 18) and the "large inclination state" in step S72 may be the same or different. If the inclination state of the machine body 10a is not a "large inclination state" (NO in step S72), the controller 30 advances the flow to step S72n. If the inclination state of the machine body 10a is a "large inclination state" (YES in step S72), the controller 30 advances the flow to step S73.

[0125] In step S72n, the controller 30 changes the target path P in the current excavation operation. For example, as shown in FIG. 6, the controller 30 may shallow the target excavation depth Ld (see example A2-1 above), shorten the target horizontal excavation distance Lh (see example A2-2 above), or set the target excavation end position Pe to the front side X1 (see example A2-3 above). The controller 30 may make only one of these changes, or may make multiple changes. Then, the controller 30 ends the process for dealing with the rear floating state in the current excavation operation (step S70), and causes the flow to proceed to step S81 (see FIG. 17).

[0126] In step S73, when the rear floating state of the machine body 10a is not the "large tilt state", the controller 30 causes only the bucket 15c to perform the excavation operation as shown in FIG. 15 (see example D above).

[0127] In step S74, the controller 30 judges whether the rear floating condition of the machine body 10a has worsened (the inclination has increased) as a result of performing the excavation operation of only the bucket 15c (performing step S73). If the rear floating condition of the machine body 10a has worsened (YES in step S74), the controller 30 advances the flow to step S74. If the rear floating condition of the machine body 10a has not worsened (NO in step S74), the controller 30 advances the flow to step S74n.

[0128] In step S74n, the controller 30 determines whether the excavation operation using only the bucket 15c (step S73) has been completed. Specifically, the controller 30 determines whether the ground angle of the bucket 15c or the bucket rotation angle φ has reached a predetermined angle (excavation operation end angle). If the excavation operation using only the bucket 15c has been completed (YES in step S74n), the controller 30 ends the process for dealing with the front floating state in this excavation operation (step S70) and advances the flow to step S81 (see FIG. 17). If the excavation operation using only the bucket 15c has not been completed (NO in step S74n), the controller 30 continues the excavation operation using only the bucket 15c (returns the flow to step S73).

[0129] In step S75, the controller 30 causes the bucket 15c to move in a direction opposite to the movement of the bucket 15c along the target path P in the excavation operation (performs reverse playback of the target path P) (see example C above) as shown in Fig. 14. In detail, if the rear floating state has worsened due to the excavation operation of only the bucket 15c shown in Fig. 15 (step S73) (if YES in step S74), the controller 30 performs reverse playback of the target path P as shown in Fig. 14.

[0130] In step S76, the controller 30 judges whether the rear-floating state of the machine body 10a has been resolved by the reverse playback of the target path P (step S75). If the rear-floating state of the machine body 10a has not been resolved (NO in step S76), the controller 30 continues the reverse playback of the target path P (return to step S75). If the rear-floating state of the machine body 10a has been resolved (YES in step S76), the controller 30 ends the reverse playback of the target path P. Then, the controller 30 ends the process of dealing with the front-floating in the current excavation operation (step S70), and causes the flow to proceed to step S81 shown in FIG. 17.

[0131] In step S81, the controller 30 determines whether the bucket height H15c (see FIG. 10) in the next excavation operation is greater (deeper) than the "floating bucket height" stored in step S33 (similar to step S61). If the bucket height H15c in the next excavation operation is greater (deeper) than the floating bucket height (YES in step S81), the controller 30 advances the flow to step S82. If the bucket height H15c in the next excavation operation is the same as or smaller (shallower) than the floating bucket height (NO in step S81), the controller 30 ends the current processing flow (proceeds to RETURN). Then, the controller 30 starts the next processing flow (returns to START).

[0132] In step S82, the controller 30 performs processing to deal with the rear floating state in the next excavation operation. For example, the controller 30 changes the target path P in the next excavation operation as shown in FIG. 6. For example, the controller 30 may make the target excavation depth Ld shallower (see Example A2-1 above), may shorten the target horizontal excavation distance Lh (see Example A2-2 above), or may set the target excavation end position Pe to the front side X1 (see Example A2-3 above). The controller 30 may make only one of these changes, or may make multiple changes. Then, the controller 30 ends the current processing flow and starts the next processing flow.

[0133] (Consider) In the working machine target motion setting system 1 of this embodiment, when it is determined that the machine body 10a is in a floating state based on the inclination of the machine body 10a detected by the inclination detection device 21b shown in FIG. 1, a target motion change process may be performed. Here, a case where the target motion of the excavation motion is changed according to information other than the inclination of the machine body 10a will be considered. For example, a case where the target motion of the excavation motion is changed according to shape information of the surface of the work object (e.g., the ground surface) will be considered (a considered example). In this considered example, even if the shape of the work object is the same, whether or not the machine body 10a is in a floating state changes when the environment such as the quality of the work object (e.g., soil quality) changes. In addition, a database showing the relationship between the shape information of the surface of the work object and the target motion may be required. In this case, the processing load of the controller 30 may be large. On the other hand, in this embodiment, when it is determined that the machine body 10a is in a floating state based on the detected (actual) inclination of the machine body 10a, a target motion change process may be performed. Therefore, there is no need to prepare a large amount of information, such as a database showing the relationship between the shape information of the surface of the workpiece and the target motion, and the processing load on the controller 30 can be reduced.

[0134] (Effects of the first invention) The effects of the work machine target movement setting system 1 shown in Fig. 1 are as follows. The work machine target movement setting system 1 includes a machine body 10a, a tilt detection device 21b, an attachment 15, and a controller 30. The tilt detection device 21b detects the tilt of the machine body 10a. The attachment 15 is attached to the machine body 10a and has a bucket 15c that performs excavation work. The controller 30 sets a target movement for the excavation operation of the bucket 15c.

[0135] [Configuration 1] The controller 30 judges whether the machine body 10a is in a floating state relative to the ground surface based on the inclination of the machine body 10a detected by the inclination detection device 21b. When the target motion change condition set in the controller 30 is satisfied, the controller 30 performs a target motion change process. The target motion change process is a process for changing the target motion to a side where the inclination of the machine body 10a becomes smaller. The target motion change condition includes that the machine body 10a is in a floating state.

[0136] In the above [Configuration 1], when a target motion change condition including the machine body 10a being in a floating state is satisfied, the controller 30 performs a target motion change process to change the target motion to a side where the inclination of the machine body 10a becomes smaller. Therefore, when the machine body 10a is in a floating state, the controller 30 can change the target motion to a side where the inclination of the machine body 10a becomes smaller. Therefore, it is possible to suppress the floating state of the machine body 10a when the work machine 10 operates according to the target motion.

[0137] (Effects of the second invention) [Configuration 2] The target motion change process changes one or both of the target bucket ground angle θs at the start of excavation, which is the angle of the bucket 15c with respect to the ground at the start position of the excavation motion, and the target path P of the bucket 15c in the excavation motion.

[0138] The above [Configuration 2] provides the following effects. The reaction force F (see Figs. 3 and 5) that the bucket 15c receives from the work target changes depending on the angle (ground angle) of the bucket 15c with respect to the ground at the start position of the excavation operation and the path of the bucket 15c in the excavation operation. This reaction force F may cause the machine body 10a to float. Therefore, in the above [Configuration 2], the change in the target operation is a change in one or both of the target bucket ground angle θs at the start of the excavation operation, which is the angle of the bucket 15c with respect to the ground at the start position of the excavation operation, and the target path P of the bucket 15c in the excavation operation. Therefore, it is possible to change one or both of the target bucket ground angle θs at the start of the excavation operation and the target path P so that the reaction force F that the bucket 15c receives from the work target when the bucket 15c is performing the excavation operation is suppressed. As a result, it is possible to suppress the floating state of the machine body 10a.

[0139] (Effects of the third invention) [Configuration 3] The target operation change condition includes a front floating state handling condition. The front floating state handling condition includes a front floating state in which the front X1 portion of the machine body 10a is floating above the ground surface, as shown in Fig. 3. When the front floating state handling condition is satisfied, the controller 30 changes one or both of the target bucket ground angle θs at the start of excavation and the target excavation depth Ld of the bucket 15c during the excavation operation in the target operation change process, as shown in Fig. 4.

[0140] The above [Configuration 3] provides the following effects. The reaction force F (see FIG. 3) that the bucket 15c receives from the work object when the bucket 15c is performing the excavation operation changes depending on the angle of the bucket 15c with respect to the ground at the start position of the excavation operation and the excavation depth of the bucket 15c during the excavation operation. This reaction force F may cause the machine body 10a to be in a front-floating state. Therefore, in the above [Configuration 3], when the machine body 10a is in a front-floating state, one or both of the excavation start target bucket ground angle θs and the target excavation depth Ld may be changed. Therefore, one or both of the excavation start target bucket ground angle θs and the target excavation depth Ld can be changed so that the reaction force F that the bucket 15c receives from the work object in an upward direction (e.g., the upper side Z1) is suppressed. As a result, the front-floating state of the machine body 10a can be suppressed.

[0141] (Effect of the fourth invention) [Configuration 4] The target operation change condition includes a post-floating state handling condition. The post-floating state handling condition includes a post-floating state in which the rear X2 portion of the machine body 10a is floating above the ground surface, as shown in FIG. 5. When the post-floating state handling condition is satisfied, the controller 30 changes one or more of the target horizontal excavation distance Lh, the target excavation depth Ld of the bucket 15c in the excavation operation, and the target excavation end position Pe, as shown in FIG. 6, in the target operation change process. The target horizontal excavation distance Lh is the excavation distance in the horizontal direction of the bucket 15c in the excavation operation. The target excavation end position Pe is the position where the excavation operation ends.

[0142] The above [Configuration 4] provides the following effects. Depending on the horizontal excavation distance, excavation depth, and excavation end position of the bucket 15c in the excavation operation, the reaction force F (see FIG. 5) that the bucket 15c receives from the work object when the bucket 15c is performing the excavation operation may change. This reaction force F may cause the machine body 10a to be in a rear-floating state. Therefore, in the above [Configuration 4], when the machine body 10a is in a rear-floating state, one or more (parameters) of the target horizontal excavation distance Lh, the target excavation depth Ld, and the target excavation end position Pe may be changed. Therefore, one or more of the target horizontal excavation distance Lh, the target excavation depth Ld, and the target excavation end position Pe can be changed so that the reaction force F that the bucket 15c receives from the work object in a downward direction (for example, the lower side Z2) is suppressed. As a result, the rear-floating state of the machine body 10a can be suppressed.

[0143] (Effect of the fifth aspect of the invention) [Configuration 5] The controller 30 stores a floating state bucket height, which is the position of the bucket 15c in the height direction (bucket height H15c) when the machine body 10a is in a floating state, as shown in Fig. 10. The controller 30 limits the change of the target motion in the target motion change process when the bucket 15c performs an excavation motion at a position above the height threshold. The height threshold is a threshold that is set based on the floating state bucket height.

[0144] The above [Configuration 5] provides the following effects. When the bucket 15c excavates at a position (shallow position, for example, the position on the upper side Z1) above the floating state bucket height, the risk of the machine body 10a becoming in a floating state is lower than when the bucket 15c excavates at the same height or a position (deep position) below the floating state bucket height. Also, when the bucket 15c excavates at a position above the floating state bucket height, if the target operation is changed too much to the side where the inclination of the machine body 10a becomes smaller, the amount of the work object excavated by the bucket 15c may be reduced too much. Therefore, in the above [Configuration 5], when the bucket 15c performs an excavation operation at a position above the height threshold based on the floating state bucket height, the controller 30 limits the change of the target operation in the target operation change process. Therefore, when the bucket 15c performs an excavation operation at a position above the height threshold, the amount of the work object excavated by the bucket 15c can be secured.

[0145] (Effect of the sixth aspect of the invention) 7, the attachment 15 includes an arm 15b to which a bucket 15c is rotatably attached. A bucket rotation angle allowable range is set in the controller 30, which is an allowable range of the angle of the bucket 15c relative to the arm 15b (bucket rotation angle φ).

[0146] [Configuration 6] When performing the target operation change process, the controller 30 determines the changed excavation start target bucket ground angle θs (step S11 in FIG. 9). If the angle of the bucket 15c with respect to the arm 15b (bucket rotation angle φ) for positioning the bucket 15c at the determined excavation start target bucket ground angle θs is outside the bucket rotation angle allowable range, the controller 30 performs the following process. In this case (if NO in step S13 in FIG. 9), the controller 30 changes the target excavation start position Ps, which is the position where the excavation operation is started.

[0147] In the above [Configuration 6], when the bucket rotation angle φ is outside the bucket rotation angle allowable range, the target excavation start position Ps is changed. Therefore, with the bucket rotation angle φ being within the bucket rotation angle allowable range, it becomes easy to set the ground angle of the bucket 15c at the start position of the excavation operation (target excavation start position Ps) to the changed target bucket ground angle θs for excavation start. As a result, the front floating state of the machine body 10a can be suppressed.

[0148] (Effects of the seventh aspect of the invention) [Configuration 7] In the target motion change process, the controller 30 shown in FIG. 1 changes the amount of change in the target motion according to the inclination of the machine body 10a detected by the inclination detection device 21b (see FIG. 11).

[0149] With the above [Configuration 7], the controller 30 can set the change amount of the target motion to an appropriate change amount according to the inclination of the machine body 10a. As a result, the floating state of the machine body 10a can be suppressed compared to when the change amount of the target motion is too small. Also, the amount of excavation of the work object by the bucket 15c can be secured compared to when the change amount of the target motion is too large.

[0150] (Effect of the eighth aspect of the invention) [Configuration 8] If the target motion change condition is satisfied when the bucket 15c performs an excavation operation with the changed target motion, the controller 30 further changes the target motion to one that reduces the inclination of the machine body 10a in the target motion change process (see Figure 12).

[0151] The above [Configuration 8] provides the following effect. In the above [Configuration 1], when the target motion change condition including the machine body 10a being in a floating state is satisfied, the controller 30 performs a target motion change process to change the target motion to a side where the inclination of the machine body 10a becomes smaller. Then, when the bucket 15c performs an excavation operation with the changed target motion, the target motion change condition including the machine body 10a being in a floating state may be satisfied again. In this case, in the above [Configuration 8], the controller 30 further changes the target motion to a side where the inclination of the machine body 10a becomes smaller in the target motion change process (adds or accumulates the amount of change). Therefore, when the bucket 15c performs an excavation operation with the changed target motion, it is possible to prevent the machine body 10a from becoming in a floating state.

[0152] (Effect of the ninth aspect of the invention) [Configuration 9] In the target motion change process, the controller 30 limits the change of the target motion so that the accumulated change amount obtained by accumulating the change amounts of the target motion is equal to or less than the accumulated change amount limit value set in the controller 30 (see FIG. 12).

[0153] The above [Configuration 9] provides the following effect. In the above [Configuration 8], when the bucket 15c performs an excavation operation with the changed target operation and the machine body 10a again becomes floating, the controller 30 further changes the target operation to the side where the inclination of the machine body 10a becomes smaller. Therefore, it is assumed that the target operation is changed too much to the side where the inclination of the machine body 10a becomes smaller. Therefore, in the above [Configuration 9], the controller 30 limits the change of the target operation so that the integrated change amount obtained by integrating the change amount of the target operation is equal to or less than the integrated change amount limit value set in the controller 30. Therefore, the amount of excavation of the work object by the bucket 15c can be secured.

[0154] (Effect of the 10th Invention) [Configuration 10] When a target motion change condition is satisfied while the bucket 15c is performing the current excavation motion, the controller 30 changes the target motion for the next or subsequent excavation motions in the target motion change process (see steps S62 and S82 in FIG. 17).

[0155] In the above [Configuration 10], the floating state of the machine body 10a in the next and subsequent excavation operations can be suppressed. When the target motion in the next and subsequent excavation operations is changed but the target motion in the current excavation operation is not changed, it is easy to ensure the excavation amount of the work object by the bucket 15c in the current excavation operation.

[0156] (Effects of the eleventh aspect of the invention) [Configuration 11] When a target motion change condition is satisfied while the bucket 15c is performing the current excavation operation, the controller 30 changes the target motion for the current excavation operation in the target motion change process (see step S52n in FIG. 18 and step S72n in FIG. 19).

[0157] In the above [Configuration 11], the floating state of the machine body 10a during the current excavation operation can be suppressed.

[0158] (Effects of the twelfth aspect of the invention) [Configuration 12] The target motion change condition includes a reverse playback execution condition. The reverse playback execution condition includes that the machine body 10a is in a floating state, and the inclination of the machine body 10a detected by the inclination detection device 21b is a specific inclination state set in the controller 30. As shown in FIG. 14, when the reverse playback execution condition is satisfied, the controller 30 performs the following process in the target motion change process. In this case, the controller 30 changes the target motion so that the bucket 15c moves in a direction opposite to the direction of movement of the bucket 15c along the target path P of the bucket 15c (see reverse playback in Example C above).

[0159] By the above [Configuration 12], when the bucket 15c operates in the direction opposite to the direction of movement of the bucket 15c along the target path P, the reaction force F (see Figs. 3 and 5) acting on the bucket 15c from the work object is reduced. Therefore, the floating state of the machine body 10a can be suppressed.

[0160] (Effects of the thirteenth aspect of the invention) [Configuration 13] The target motion change condition includes a motion element limiting condition. The motion element limiting condition includes that the machine body 10a is in a floating state, and that the inclination of the machine body 10a detected by the inclination detection device 21b is in a specific inclination state set in the controller 30. When the motion element limiting condition is satisfied, as shown in FIG. 15, the controller 30 changes the target motion in the target motion change process so that only the bucket 15c among the elements of the attachment 15 is operated.

[0161] The above [Configuration 13] provides the following effect. When only the bucket 15c is in motion, the reaction force F (see Figs. 3 and 5) acting on the bucket 15c from the work object is reduced, compared to when the bucket 15c and elements other than the bucket 15c among the elements of the attachment 15 are in motion. This makes it possible to suppress the floating state of the machine body 10a.

[0162] (Effects of the fourteenth aspect of the invention) [Configuration 14] The target motion change condition includes a discharge condition. The discharge condition includes that the rear X2 portion of the machine body 10a is in a floating state after floating from the ground surface and no excavation motion is being performed, as shown in Fig. 16. When the discharge condition is satisfied, the controller 30 changes the target motion in the target motion change process so that the bucket 15c performs a discharge motion.

[0163] In the above [Configuration 14], when the machine body 10a is in the rear floating state, the work object may be discharged from the bucket 15c. In this case, the load due to the mass of the work object acting on the bucket 15c is reduced. As a result, the rear floating state of the machine body 10a is suppressed.

[0164] (Effects of the fifteenth aspect of the invention) [Configuration 15] The controller 30 automatically controls the attachment 15 so that the excavation operation of the bucket 15c is performed in accordance with a target operation.

[0165] The above [Configuration 15] makes it possible to suppress the floating state of the machine body 10a when the work machine 10 operates under automatic control.

[0166] (Modification) The above embodiment may be modified in various ways. For example, the modified examples of the above embodiment may be combined in various ways. For example, the number of components (including modified examples) of the above embodiment may be changed, or some of the components may not be provided. For example, the components may be fixed or connected directly or indirectly. For example, the connection of each component shown in FIG. 2 may be changed. For example, the arrangement of the components may be changed. For example, the inclusion relationship of the components may be changed in various ways. For example, a component described as a lower component included in a higher-level component may not be included in this higher-level component, but may be included in another component. For example, a component described as a plurality of different members or parts may be treated as a single member or part. For example, a component described as a single member or part may be provided as a plurality of different members or parts. For example, the order of steps in a flowchart (see FIG. 17, etc.) may be changed, some of the steps may not be performed, or steps of different flowcharts may be combined. For example, various parameters (for example, various parameters of the target path P, etc.) used in the control by the controller 30 shown in FIG. 1 may not be the same as these various parameters, and may be parameters that can be converted into various parameters. For example, the controller 30 may perform substantially the same processing as that of the above embodiment (including the modified example). Various processing may be combined in various ways. For example, each component may have only a part of each feature (function, arrangement, shape, operation, etc.). [Explanation of symbols]

[0167] 1. Work Machine Target Operation Setting System 10a Machine body 15 Attachment 15b Arm 15c Bucket 21b Tilt detection device 30 Controller Ld Target drilling depth Lh Target horizontal drilling distance P Target Route Pe Target drilling end position Ps Target drilling start position θs Excavation start target bucket ground angle

Claims

1. The machine body, a tilt detection device for detecting a tilt of the machine body; An attachment having a bucket attached to the machine body for performing excavation work; A controller that sets a target operation of the excavation operation of the bucket; Equipped with The controller: determining whether or not the machine body is in a floating state with respect to a ground surface based on the inclination of the machine body detected by the inclination detection device; When a target motion change condition set in the controller is satisfied, a target motion change process is performed to change the target motion to a side in which the inclination of the machine body becomes smaller; The target motion change condition includes that the machine body is in a floating state. Work machine target motion setting system.

2. 2. The work machine target operation setting system according to claim 1, The target motion change process includes: An excavation start target bucket ground angle, which is the angle of the bucket with respect to the ground at the start position of the excavation operation; A target path of the bucket in the excavation operation; A change in one or both of Work machine target motion setting system.

3. 3. A work machine target operation setting system according to claim 2, the target motion change condition includes a front floating state handling condition including a front portion of the machine body being in a front floating state with respect to a ground surface, When the front floating state handling condition is satisfied, the controller performs the target motion change process. The excavation start target bucket ground angle; a target excavation depth of the bucket in the excavation operation; change one or both of the Work machine target motion setting system.

4. 3. A work machine target operation setting system according to claim 2, The target motion change condition includes a rear floating state handling condition including a rear portion of the machine body being in a rear floating state with respect to a ground surface, When the rear floating state handling condition is satisfied, the controller performs the target action change process. A target horizontal excavation distance, which is an excavation distance in the horizontal direction of the bucket during the excavation operation; a target excavation depth of the bucket in the excavation operation; A target excavation end position at which the excavation operation ends; change one or more of the following: Work machine target motion setting system.

5. 3. A work machine target operation setting system according to claim 2, The controller: A floating state bucket height, which is the position of the bucket in the height direction when the machine body is in the floating state, is stored; limiting the change of the target motion in the target motion change process when the bucket performs the excavation motion at a position above a height threshold, the height threshold being a threshold set based on the floating state bucket height; Work machine target motion setting system.

6. 3. A work machine target operation setting system according to claim 2, The attachment includes an arm to which the bucket is rotatably attached; a bucket rotation angle allowable range, which is an allowable range of an angle of the bucket with respect to the arm, is set in the controller; The controller: When performing the target motion change process, the excavation start target bucket ground angle after the change is determined; When an angle of the bucket with respect to the arm for positioning the bucket at the determined excavation start target bucket ground angle is outside the bucket rotation angle allowable range, a target excavation start position, which is a position at which the excavation operation is started, is changed. Work machine target motion setting system.

7. 3. A work machine target operation setting system according to claim 2, the controller changes an amount of change in the target motion in response to the inclination of the machine body detected by the inclination detection device in the target motion change process. Work machine target motion setting system.

8. 3. A work machine target operation setting system according to claim 2, When the target motion change condition is satisfied when the bucket is caused to perform the excavation motion with the changed target motion, the controller further changes the target motion to a side where the inclination of the machine body becomes smaller in the target motion change process. Work machine target motion setting system.

9. 9. A work machine target operation setting system according to claim 8, the controller limits the change of the target motion in the target motion change process so that an integrated change amount obtained by integrating the change amounts of the target motion is equal to or less than an integrated change amount limit value set in the controller. Work machine target motion setting system.

10. 2. The work machine target operation setting system according to claim 1, When the target motion change condition is satisfied while the bucket is performing the current excavation motion, the controller changes the target motion of the next or subsequent excavation motions in the target motion change process. Work machine target motion setting system.

11. 2. The work machine target operation setting system according to claim 1, the controller changes the target motion for the current excavation motion in the target motion change process when the target motion change condition is satisfied while the bucket is performing the current excavation motion. Work machine target motion setting system.

12. 12. A work machine target operation setting system according to claim 11, the target motion change condition includes a reverse playback execution condition including that the machine body is in a floating state and the inclination of the machine body detected by the inclination detection device is in a specific inclination state set in the controller, when the reverse playback execution condition is satisfied, in the target motion change process, the controller changes the target motion so that the bucket moves in a direction opposite to a direction of movement of the bucket along the target path of the bucket. Work machine target motion setting system.

13. 12. A work machine target operation setting system according to claim 11, the target motion change condition includes a motion element limiting condition including that the machine body is in a floating state and that the inclination of the machine body detected by the inclination detection device is in a specific inclination state set in the controller; When the motion element restriction condition is satisfied, the controller changes the target motion in the target motion change process so as to operate only the bucket among the elements of the attachment. Work machine target motion setting system.

14. 12. A work machine target operation setting system according to claim 11, The target motion change condition includes a discharge condition including a state in which a rear portion of the machine body is in a floating state after floating from a ground surface and the excavation motion is not being performed, When the discharge condition is satisfied, the controller changes the target operation in the target operation change process so as to cause the bucket to perform a discharge operation. Work machine target motion setting system.

15. 2. The work machine target operation setting system according to claim 1, The controller automatically controls the attachment so that an excavation operation with the bucket is performed in accordance with the target operation. Work machine target motion setting system.

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