Work machine control device, work machine, remote control system, and work machine control method

Abstract

Provided is a work machine control device that makes it possible to assist in an operation by an operator.　A control device (51) is for a work machine (1) comprising a machine body (2), a boom (21) having a base-end section supported by the machine body (2) so as to be rotatable about a first rotation axis (J1), an arm (22) having a base-end section supported by a leading-end section of the boom (21) so as to be rotatable about a second rotation axis (J2), and a work tool (T) supported by a leading-end section of the arm (22) so as to be rotatable about a third rotation axis (J3). In a fixed posture mode, the control device rotates the boom (21), the arm (22), and the work tool (T) so as to cause the work tool (T) to linearly move in a fixed posture in accordance with a rotation operation of the boom (21) or the arm (22).

Description

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[0001] The present invention relates to a control device for a work machine, a work machine, a remote control system, and a control method for a work machine.

[0002] The work machine disclosed in Patent Document 1 includes a lower traveling body, an upper revolving body, and a work device provided on the upper revolving body. The work device includes a boom that can swing in the vertical direction, an arm provided at the tip of the boom and capable of swinging in the front-rear direction or the vertical direction, and a working tool (for example, a pipe joining attachment) that is connected to the tip of the arm and grips a pipe. In this work machine, by an operation by an operator, the pipe gripped by the working tool is brought sufficiently close to the joint pipe arranged in the groove in the ground, and then the pipe is joined to the joint pipe.

[0003] Japanese Patent Laid-Open Gazette "JP-A-2023-62320"

[0004] In the work machine of Patent Document 1, when linearly moving the working tool in a fixed posture (for example, horizontal movement or vertical movement) while gripping a pipe, the operator needs to skillfully operate the working tool, boom, and arm, so a high level of operating skill is required. Thus, the above-described linear movement operation is very burdensome for the operator.

[0005] The present invention has been made to solve such problems of the prior art, and an object thereof is to provide a control device for a work machine, a work machine, a remote control system, and a control method for a work machine that can assist (support) an operation by an operator.

[0006] A control device for a work machine according to an aspect of the present invention is a control device for a work machine including a machine body, a boom whose base end is rotatably supported by the machine body around a first rotation axis, an arm whose base end is rotatably supported by the tip of the boom around a second rotation axis, and a working tool rotatably supported by the tip of the arm around a third rotation axis. In the case of a fixed posture mode, the boom, the arm, and the working tool are rotated so that the working tool linearly moves in a fixed posture in accordance with a rotation operation of the boom or the arm.

[0007] A working machine according to one aspect of the present invention comprises a machine body, a boom whose base end is supported by the machine body so as to be rotatable around a first rotation axis, an arm whose base end is supported by the tip of the boom so as to be rotatable around a second rotation axis, a working tool supported by the tip of the arm so as to be rotatable around a third rotation axis, and the control device described above.

[0008] A remote control system according to one aspect of the present invention comprises the above-mentioned work machine and a remote device for remotely operating the work machine, wherein the remote device comprises a boom operating member that is oscillated, an arm operating member that is oscillated, and a mode indicator unit that instructs the control device to enter the constant posture mode.

[0009] A control method for a work machine according to one aspect of the present invention comprises a machine body, a boom whose base end is supported by the machine body so as to be rotatable around a first rotation axis, an arm whose base end is supported by the tip of the boom so as to be rotatable around a second rotation axis, and a work tool supported by the tip of the arm so as to be rotatable around a third rotation axis, wherein in a constant posture mode, the control device rotates the boom, the arm, and the work tool in response to a rotation operation of the boom or the arm so as to move the work tool in a straight line while maintaining a constant posture.

[0010] The control device for the above-mentioned work machine can assist (support) the operator's operation.

[0011] This is an overall side view of the work machine. This is a plan view with some of the work equipment of the work machine omitted. This is a schematic diagram of the hydraulic system and control system of the work machine. This is an electrical block diagram of the work machine of an embodiment. This is a diagram showing an example of the display of the display device. This is an explanatory diagram showing the horizontal movement of the work tool in a constant posture. This is an explanatory diagram showing the vertical movement of the work tool in a constant posture. This is a diagram showing an example of the calculation of the horizontal movement range. This is a diagram showing an example of the calculation of the vertical movement range. This is a diagram showing an example of the display of the display device. This is a flowchart showing an example of setting the posture of the work tool. This is a flowchart showing an example of linear movement control for moving the work tool in a straight line in a constant posture. This is a flowchart showing an example of horizontal movement control. This is a flowchart showing an example of vertical movement control. This is a flowchart showing an example of drive control when the arm button is ON and the boom is operated. This is a flowchart showing another example of drive control when the arm button is ON and the boom is operated. This is a flowchart showing an example of drive control when the boom button is ON and the arm is operated. This is a flowchart showing another example of drive control when the boom button is ON and the arm is operated. This is a block diagram showing the configuration of the remote control system.

[0012] One embodiment of the present invention will be described below with reference to the drawings.

[0013] First, let's explain the overall configuration of the work machine 1. Figure 1A is an overall side view of the work machine 1. Figure 1B is a plan view of the work machine 1 with some parts of the work device 20 omitted.

[0014] The implement 1 of this embodiment is a backhoe, but a work tool T is attached in place of the bucket. The work tool T is a pipe joining attachment 100 that grips a long object W (for example, a pipe W1). The implement 1 comprises a mobile body 30 and a work device 20 provided on the body 30. The body 30 comprises a machine body 2 (turntable) and a travel device 10 that moves the machine body 2. On top of the machine body 2 is a driver's seat 4 where the operator sits, and a protective mechanism 6 that protects the driver's seat 4 from the front, back, left, right, and above.

[0015] The protective mechanism 6 is also called a cabin. The protective mechanism 6 has a frame attached to the aircraft body 2, a roof attached to the top of the frame, and multiple side walls attached to the front, rear, and left and right sides of the frame, respectively. Each side wall is provided with a transparent section (so-called window) that allows the driver's seat 4 to see the surroundings. Such a protective mechanism 6 separates the space around the driver's seat 4 from the outside. In other words, the protective mechanism 6 forms the driver's compartment 4R containing the driver's seat 4. Note that the protective mechanism 6 may be a canopy or the like, rather than a cabin.

[0016] Inside the protective mechanism 6 (operator's cab 4R), around the driver's seat 4, there are operating devices 5 for operating the work implement 1. The operator can operate the operating devices 5 while seated in the driver's seat 4.

[0017] In this embodiment, the direction the driver (operator) seated in the driver's seat 4 faces (direction of arrow YA1 in Figures 1A and 1B) is forward, and the opposite direction (direction of arrow YA2 in Figures 1A and 1B, etc.) is backward. The left side of the driver (the front side in Figure 1A, the direction of arrow XB1 in Figure 1B) is to the left, and the right side of the driver (the back side in Figure 1A, the direction of arrow XB2 in Figure 1B) is to the right. The horizontal direction, which is perpendicular to the front-rear direction YA3, is the width direction XB3 (see Figure 1B). The direction from the center of the width direction XB3 of the machine body 2 toward the right or left is the outward direction in the width direction.

[0018] The traveling device 10 is a device for moving the machine body 2, and has a traveling frame 11 and a traveling mechanism 12. The traveling frame 11 (track frame) is a structure to which the traveling mechanism 12 is attached around the perimeter and which supports the machine body 2 on top.

[0019] The running mechanism 12 is, for example, a crawler-type running mechanism. The running mechanism 12 is provided on the left and right sides of the running frame 11, respectively. The running mechanism 12 includes an idler 13, a drive wheel 14, a plurality of road wheels 15, an endless crawler belt 16, and a running motor (left running motor ML, right running motor MR).

[0020] The idler 13 is located at the front of the running frame 11. The drive wheel 14 is located at the rear of the running frame 11. Multiple road wheels 15 are provided between the idler 13 and the drive wheel 14. The crawler belt 16 is wrapped around the idler 13, the drive wheel 14, and the road wheels 15.

[0021] The left-hand drive motor ML is included in the drive mechanism 12 located on the left side of the drive frame 11. The right-hand drive motor MR is included in the drive mechanism 12 located on the right side of the drive frame 11. Both the left-hand drive motor ML and the right-hand drive motor MR are composed of hydraulic motors. In each drive mechanism 12, the power from the left-hand drive motor ML and the right-hand drive motor MR drives the drive wheels 14 to rotate, causing the crawler belt 16 to circumferentially move around.

[0022] A dozer device 18 is mounted on the front of the traveling device 10. The dozer device 18 swings up and down by the extension and retraction of the dozer cylinder C3. The dozer cylinder C3 is attached to the traveling frame 11. The dozer cylinder C3 is composed of a hydraulic cylinder.

[0023] The machine body 2 is supported on the travel frame 11 via a slewing bearing 3 so as to be able to rotatably around axis Zm (the axis extending in the vertical direction: Z-axis). The slewing motor MT consists of a hydraulic motor (a hydraulic actuator included in hydraulic equipment). The machine body 2 rotates around axis Zm by the power of the slewing motor MT.

[0024] The working device 20 is mounted on the machine body 2. For example, the working device 20 is supported at the front of the machine body 2. The working device 20 includes a boom 21, an arm 22, a work tool T, and hydraulic actuators (boom cylinder C1, attachment swing cylinder C2, dozer cylinder C3, swing cylinder C4, arm cylinder C9). The base end of the boom 21 is supported by a swing bracket 24 so as to be rotatable around a first rotation axis J1 (an axis extending in the width direction of the machine body 2). As a result, the boom 21 can swing in the up and down direction (vertical direction). The arm 22 is supported at the tip of the boom 21 so as to be rotatable around a second rotation axis J2 (an axis extending in the width direction of the boom 21) which is parallel to the first rotation axis J1. As a result, the arm 22 can swing in the front and back direction or in the up and down direction.

[0025] The boom cylinder C1 is a boom drive device that rotates the boom 21 around the first rotation axis J1. The arm cylinder C9 is an arm drive device that rotates the arm 22 around the second rotation axis J2. The attachment swing cylinder C2 is a work tool drive device that rotates the attachment 100 (work tool T) around the third rotation axis J3, which is parallel to the first rotation axis J1.

[0026] The attachment 100 is pivotably mounted on the tip of the arm 22, replacing the bucket. As shown in Figure 1A, the attachment 100 is a work tool T that grips a joining member (e.g., pipe W1), which is an example of an object to be gripped W, and joins the gripped pipe W1 to a member to be joined (e.g., pipe to be joined) placed in a target area (e.g., groove G). The groove G is a groove formed below the ground surface (a groove underground), such as a flat-bottomed groove formed by excavating the ground. The target area does not have to be a groove; for example, it may be a support base (e.g., a concrete support base exposed above ground, or a steel support base in a field setting) on ​​which the pipe to be joined W2 is placed on the upper surface and which at least a part of it is formed above the ground surface.

[0027] As shown in Figure 1A, the attachment 100 includes an arm connection portion 111, a gripping portion 112, an axial movement mechanism 113, a horizontal rotation mechanism 114, and a joining function portion 115 (a portion that contacts the pipe to be joined). Further details of the attachment 100 will be described later.

[0028] The work machine 1 can be fitted with other work tools T (hydraulic attachments) that can be driven by a hydraulic actuator, instead of attachment 100 (for example, a grapple). Examples of these other work tools T include a tilt rotator, hydraulic breaker, hydraulic crusher, angle broom, earth auger, pallet fork, sweeper, mower, snow blower, etc.

[0029] In the work machine 1, for example, the rotation axes of the boom 21, arm 22, and work tool T (first rotation axis J1, second rotation axis J2, and third rotation axis J3) are parallel, but the three axes do not necessarily have to be in a parallel / perpendicular relationship. For example, in the case of the work machine 1 having a tilt rotator, the tilt rotator can be rotated to a predetermined angle (e.g., 360 degrees) in the horizontal plane by operating the rotation operation part (e.g., joystick, dial, etc.) provided on the work operation member 19L with the left hand, and the tilt angle of the tilt rotator can be changed to a predetermined angle (e.g., 45 degrees) to the left or right by operating the tilt operation part (e.g., joystick, dial, etc.) provided on the work operation member 19R with the right hand. Therefore, in the case of a work machine 1 having a tilt rotator, the rotation axes of the boom 21 and the arm 22 (first rotation axis J1 and second rotation axis J2) are parallel, but the third rotation axis J3 is not necessarily parallel to the first rotation axis J1 and the second rotation axis J2.

[0030] The swing bracket 24 swings from side to side by rotating around the fourth rotation axis J4 (the axis extending in the vertical direction of the machine body 2) due to the extension and retraction of the swing cylinder C4 located inside the machine body 2. The boom 21 swings up and down (back and forth) due to the extension and retraction of the boom cylinder C1. The arm 22 swings up and down (back and forth) due to the extension and retraction of the arm cylinder C9. The attachment 100 swings up and down (back and forth) due to the extension and retraction of the attachment swing cylinder C2. The attachment swing cylinder C2 is called the bucket cylinder if a bucket is attached to the tip of the arm 22. The swing cylinder C4, boom cylinder C1, arm cylinder C9, and attachment swing cylinder C2 are all composed of hydraulic cylinders.

[0031] Figure 2A is a schematic diagram of the hydraulic system and control system of the work machine 1. The hydraulic system of the work machine 1 includes a first hydraulic pump P1, a second hydraulic pump P2, a third hydraulic pump P3, and a plurality of control valves V1 to V10. The first hydraulic pump P1 and the second hydraulic pump P2 are variable displacement hydraulic pumps. The third hydraulic pump P3 is a constant displacement hydraulic pump. The first hydraulic pump P1, the second hydraulic pump P2, and the third hydraulic pump P3 are driven by the power of the prime mover E1 to discharge hydraulic fluid stored in the hydraulic fluid tank. In this embodiment, the hydraulic system of the work machine 1 is equipped with three hydraulic pumps (first hydraulic pump P1, second hydraulic pump P2, and third hydraulic pump P3), but the number is not limited.

[0032] The multiple control valves V1 to V10 are each valves (solenoid control valves) that control the flow rate of hydraulic fluid supplied to hydraulic actuators (work system hydraulic actuators, travel system hydraulic actuators). The multiple control valves V1 to V10 are solenoid 3-position directional control valves whose spool position is switched by the hydraulic fluid (pilot oil) supplied from the third hydraulic pump P3. That is, the multiple control valves V1 to V10 have solenoid valves, and the pressure of the pilot oil acting on the spool changes depending on the opening degree of the solenoid valve, thereby changing the position of the spool. In this embodiment, solenoid 3-position directional control valves with incorporated solenoid valves are shown, but the solenoid valves may be configured as separate components. Furthermore, the multiple control valves V1 to V10 are not limited to 3-position directional control valves, but may also be 2-position directional control valves, 4-position directional control valves, etc.

[0033] The boom control valve V1 controls the boom cylinder C1. The oscillating control valve V2 (= bucket control valve) controls the attachment oscillating cylinder C2 (= bucket cylinder). The dozer control valve V3 controls the dozer cylinder C3. The swing control valve V4 controls the swing cylinder C4. The right travel control valve V5 controls the travel system hydraulic actuator (right travel motor MR) of the first travel device 10R. The left travel control valve V6 controls the travel system travel hydraulic actuator (left travel motor ML) of the second travel device 10L. The first auxiliary control valve V7 controls the auxiliary actuator. In Figure 2A, the first auxiliary control valve V7 controls the flow rate of hydraulic fluid supplied to the attachment 100 (i.e., the hydraulic actuator for pipe joining) as an auxiliary actuator. The second auxiliary control valve V8 controls the auxiliary actuator. The arm control valve V9 controls the arm cylinder C9. The slewing control valve V10 controls the slewing motor MT.

[0034] The boom control valve V1, swing control valve V2, dozer control valve V3, swing control valve V4, and right travel control valve V5 are connected to the first discharge oil passage 41, which is connected to the first hydraulic pump P1. The left travel control valve V6, first auxiliary control valve V7, second auxiliary control valve V8, arm control valve V9, and slewing control valve V10 are connected to the second discharge oil passage 42, which is connected to the second hydraulic pump P2.

[0035] Hereafter, for the sake of explanation, the group of control valves V1 to V5 will be referred to as the first block BL1, and the group of control valves V6 to V10 will be referred to as the second block BL2.

[0036] A communication valve V11 is provided between the first block BL1 and the second block BL2. The communication valve V11 is a switching valve that switches between a first position and a second position, and connects the first discharge oil passage 41 and the second discharge oil passage 42, respectively. When the communication valve V11 is in the first position, the first discharge oil passage 41 and the second discharge oil passage 42 are connected via the communication valve V11, and when the communication valve V11 is in the second position, the communication between the first discharge oil passage 41 and the second discharge oil passage 42 is blocked by the communication valve V11. Note that the communication valve V11 is not limited to a two-position switching valve, but may also be a three-position switching valve, a four-position switching valve, etc. Note that the hydraulic system of the work machine 1 may be configured without a communication valve V11.

[0037] The work machine 1 is equipped with a slewing device 25 (see Figure 2A). The slewing device 25 is a device that includes a slewing bearing 3, a slewing motor MT, and hydraulic pumps (first hydraulic pump P1, second hydraulic pump P2).

[0038] As shown in Figure 2A, the attachment 100 is equipped with a first control valve V71, a second control valve V72, and a third control valve V73, from which the hydraulic fluid from the first pre-control valve V7 is branched and supplied. The first control valve V71 is an electromagnetic control valve for controlling the opening and closing of the gripping portion 112. The second control valve V72 is an electromagnetic control valve for controlling the axial movement mechanism 113. The third control valve V73 is an electromagnetic control valve for controlling the horizontal rotation mechanism 114.

[0039] Next, the configuration of the control system for the work machine 1 will be explained using Figures 2A and 2B. Figure 2B is an electrical block diagram of the work machine 1.

[0040] As shown in Figures 2A and 2B, the control system of the work machine 1 includes a control device 51. The control device 51 consists of a CPU (processor), electronic and electrical circuits, a program, etc. The control device 51 includes a hydraulic control unit 53 that controls the hydraulic system. The hydraulic control unit 53 is a work control device that controls the hydraulic systems of the work machine 20 and the travel machine 10. The hydraulic control unit 53 consists of a CPU (processor), electronic and electrical circuits, a program, etc., provided in the control device 51. The hydraulic control unit 53 controls the hydraulic equipment provided in the work machine 1, for example, a plurality of control valves V1 to V10, a communication valve V11, and hydraulic pumps (first hydraulic pump P1, second hydraulic pump P2). Note that the hydraulic control unit 53 can be anything that controls hydraulic equipment, and the controlled objects are not limited to this embodiment.

[0041] An operating device 5 is connected to the control device 51. The operating device 5 includes work operating members (work operating member 19L, work operating member 19R, work operating member 19D) and travel operating members (travel operating member 20L, travel operating member 20R).

[0042] The control device 51 is connected to work operation members (work operation member 19L, work operation member 19R, and work operation member 19D). Work operation member 19L is positioned so that the driver (operator) can operate it with their left hand, work operation member 19R is positioned so that the driver can operate it with their right hand, and work operation member 19D is positioned separately from work operation member 19R on the right side of the driver's seat 4 so that the driver can operate it with their right hand. Work operation members 19L and 19R are levers having a potentiometer (detection device) that detects the amount of oscillation (operation amount), and are levers that can swing forward, backward, right, and left. Work operation member 19D is a lever having a potentiometer (detection device) that detects the amount of oscillation (operation amount), and is a lever that can swing forward and backward.

[0043] For example, when the work operation member 19L swings in the front-rear direction, it functions as the arm operation member 19LA, and when it swings in the left-right direction, it functions as the turning operation member. As shown in FIG. 2A and FIG. 4 to be described later, the work operation member 19L (arm operation member 19LA) includes a first instruction portion 17L (for example, an arm button) operated by an operator. The arrangement position of the first instruction portion 17L is not particularly limited, but it is preferably provided at a position where it can be operated by any finger of the hand that holds the arm operation member 19LA while the operator holds and swings the arm operation member 19LA.

[0044] For example, when the work operation member 19R swings in the front-rear direction, it functions as the boom operation member 19RB, and when it swings in the left-right direction, it functions as the work tool operation member. As shown in FIG. 2A and FIG. 5 to be described later, the work operation member 19R (boom operation member 19RB) includes a second instruction portion 17R (for example, a boom button) operated by an operator. The arrangement position of the second instruction portion 17R is not particularly limited, but it is preferably provided at a position where it can be operated by any finger of the hand that holds the boom operation member 19RB while the operator holds and swings the boom operation member 19RB.

[0045] When the driver operates the work operation member 19L, the operation amount and operation direction of the work operation member 19L are detected by a potentiometer, and the detected operation amount and operation direction are input to the control device 51. The hydraulic control unit 53 excites the solenoid of the turning electromagnetic valve of the turning control valve V10 according to the operation amount and operation direction of the work operation member 19L, and controls the opening degree of the turning electromagnetic valve, or excites the solenoid of the arm electromagnetic valve of the arm control valve V9, and controls the opening degree of the arm electromagnetic valve. As a result, pilot pressure acts on the pressure receiving portion of the turning control valve V10, the position of the turning control valve V10 is switched, and the rotation direction of the turning motor MT is switched according to the position, or pilot pressure acts on the pressure receiving portion of the arm control valve V9, the position of the arm control valve V9 is switched, and the arm cylinder C9 expands and contracts according to the position.

[0046] When the operator operates the work operation member 19R, the operation amount and operation direction of the work operation member 19R are detected by a potentiometer, and the detected operation amount and operation direction are input to the control device 51. The hydraulic control unit 53 excites the solenoid of the boom solenoid valve of the boom control valve V1 according to the operation amount and operation direction of the work operation member 19R, and controls the opening degree of the boom solenoid valve, or excites the solenoid of the solenoid valve of the swing control valve V2 (referred to as the bucket solenoid valve in the bucket-mounted state) according to the operation amount and operation direction of the work operation member 19R, and controls the opening degree of the solenoid valve (bucket solenoid valve). As a result, pilot pressure acts on the pressure receiving portion of the boom control valve V1, the position of the boom control valve V1 is switched, and the boom cylinder C1 expands and contracts according to the position, or pilot pressure acts on the pressure receiving portion of the swing control valve V2, the position of the swing control valve V2 is switched, and the attachment swing cylinder C2 expands and contracts according to the position.

[0047] When the operator operates the work operation member 19D, the operation amount and operation direction of the work operation member 19D are detected by a potentiometer, and the detected operation amount and operation direction are input to the control device 51. The hydraulic control unit 53 excites the solenoid of the dozer solenoid valve of the dozer control valve V3 according to the operation amount and operation direction of the work operation member 19D, and controls the opening degree of the dozer solenoid valve. As a result, pilot pressure acts on the pressure receiving portion of the dozer control valve V3, the position of the dozer control valve V3 is switched, and the dozer cylinder C3 expands and contracts according to the position.

[0048] As described above, by operating the work operation members (work operation member 19L, work operation member 19R, work operation member 19D), the machine body 2, the boom 21, the arm 22, the attachment 100 (only swing), and the dozer device 18 can be operated.

[0049] The control device 51 is connected to a driving operation member (driving operation member 20L, driving operation member 20R). The driving operation member 20L and the driving operation member 20R are located in front of the driver's seat 4. The driving operation member 20L and the driving operation member 20R are levers having a potentiometer (detection device) for detecting the amount of swing (operation amount), and are levers that can swing forward and backward. Note that the driving operation member 20L and the driving operation member 20R are not limited to levers, but may be pedals, for example.

[0050] When the driver operates the travel control member 20L and the travel control member 20R, the amount and direction of operation of the travel control member 20L and the travel control member 20R are detected by the potentiometer, and the detected amount and direction of operation are input to the control device 51. The hydraulic control unit 53 energizes the solenoid of the left travel solenoid valve of the left travel control valve V6 according to the amount and direction of operation of the travel control member 20L, and energizes the solenoid of the right travel solenoid valve of the right travel control valve V5 according to the amount and direction of operation of the travel control member 20R. As a result, pilot pressure is applied to the pressure receiving parts of the right travel control valve V5 and the left travel control valve V6, and the right travel control valve V5 and the left travel control valve V6 are switched, and the rotation direction of the right travel motor MR and the left travel motor ML is determined.

[0051] As described above, when operating the work operation members (work operation member 19L, work operation member 19R, work operation member 19D) and the travel operation members (travel operation member 20L, travel operation member 20R), the control device 51 outputs control signals for excitation and demagnetization of the solenoids, thereby enabling control of the machine body 2, boom 21, arm 22, attachment 100, dozer device 18, first travel device 10R, and second travel device 10L.

[0052] The attachment 100 will be explained using Figure 1A. Pipe W1 and pipe W2 to be joined are, for example, earthquake-resistant pipes having an earthquake-resistant joint that can be bent at a predetermined angle. Note that pipe W1 and pipe W2 may be piping other than earthquake-resistant pipes.

[0053] As shown in Figure 1A, the attachment 100 is configured to grip the pipe W1, and the gripped pipe W1 can be rotated horizontally around a rotation axis Q extending in the vertical direction and moved in the axial direction of the pipe W1. The attachment 100 includes an arm connection part 111, a gripping part 112, an axial movement mechanism 113, a horizontal rotation mechanism 114, and a joining function part 115.

[0054] The arm connection portion 111 is located at the upper end of the attachment 100 and is connected to the other end of the arm 22 of the work machine 1.

[0055] The gripping portion 112 is supported so as to be movable in the axial direction by an axial movement mechanism 113. The gripping portion 112 grips the pipe W1. The gripping portion 112 has a pair of gripping claws 121 and a gripping drive portion 122 (see Figure 2B).

[0056] The pair of gripping claws 121 are positioned side by side in the width direction perpendicular to the axial direction so as to be able to grip the pipe W1. The base ends of the pair of gripping claws 121 are connected to the gripping drive unit 122. The pair of gripping claws 121 are rotatable around their base ends in directions in which their tips move closer together and away from each other, by the driving force of the gripping drive unit 122. The pair of gripping claws 121 grip the pipe W1 in the width direction.

[0057] As shown in Figure 1A, the axial movement mechanism 113 is supported by the horizontal rotation mechanism 114 so as to be rotatable horizontally about the rotation axis Q. When joining pipe W1 to pipe W2, the axial movement mechanism 113 moves the gripping portion 112 in the axial direction of pipe W1 gripped by the gripping portion 112.

[0058] The horizontal rotation mechanism 114 is connected to the arm 22 of the work machine 1 via the arm connection part 111. That is, the arm connection part 111 is fixed to the upper part of the horizontal rotation mechanism 114. The axial drive unit 133 is connected to the lower part of the horizontal rotation mechanism 114 so as to be rotatable horizontally around the rotation axis Q. The horizontal rotation mechanism 114 generates a driving force to rotate the axial drive unit 133 horizontally around the rotation axis Q, for example, using hydraulic pressure output from the first pre-control valve V7 to the third control valve V73 of the work machine 1.

[0059] As a result, the horizontal rotation mechanism 114 can rotate the attachment 100 horizontally around the rotation axis Q relative to the arm 22 of the work machine 1. Therefore, the pipe W1 gripped by the gripping portion 112 of the attachment 100 can be rotated along the trench G in the ground without moving or rotating the work machine 1.

[0060] When joining the gripped pipe W1 to the pipe to be joined W2, the joining function part 115 contacts the peripheral edge W2a on the end W2b side of the pipe to be joined W2, and positions the end W1b of the pipe W1 gripped by the gripping part 112 relative to the end W2b of the pipe to be joined W2 (see Figure 1A). Then, the axial movement mechanism 113 of the attachment 100 moves the pipe W1 toward the pipe to be joined W2 in its axial direction, and the end W1b of the pipe W1 is inserted into the end W2b of the pipe to be joined W2.

[0061] As shown in Figure 2B, the operating device 5 is equipped with gripping operation members (gripping button 5a, operating lever 5b, mode setting button 5e). The gripping operation members are connected to the control device 51.

[0062] The operating lever 5b is located separately from the work operation member 19L, on the left side of the driver's seat 4, in a position where the driver can operate it with their left hand. The operating lever 5b is a lever having a potentiometer (detection device) that detects the amount of swing (amount of operation), and is a lever that can swing forward, backward, right, and left.

[0063] When the operating lever 5b is operated by the operator, the amount and direction of operation of the operating lever 5b are detected by the potentiometer, and the detected amount and direction of operation are input to the control device 51. The hydraulic control unit 53 energizes the solenoid of the solenoid valve of the second control valve V72 according to the amount and direction of operation of the operating lever 5b (for example, forward or backward), and controls the opening degree of the solenoid valve. As a result, pilot pressure acts on the pressure receiving part of the second control valve V72, the position of the second control valve V72 is switched, and the axial movement mechanism 113 moves forward or backward according to the position. The hydraulic control unit 53 also energizes the solenoid of the solenoid valve of the third control valve V73 according to the amount and direction of operation of the operating lever 5b (for example, left or right), and controls the opening degree of the solenoid valve. As a result, pilot pressure acts on the pressure-receiving part of the third control valve V73, the position of the third control valve V73 is switched, and the rotation direction of the horizontal rotation mechanism 114 is switched to left rotation or right rotation according to the position.

[0064] The grip button 5a is located above the operating lever 5b and is a push button that can be pressed with the thumb of the left hand holding the operating lever 5b.

[0065] Each time the operator presses the grip button 5a, a grip ON signal or a grip OFF signal is input to the control device 51. The hydraulic control unit 53 energizes the solenoid of the solenoid valve of the first control valve V71 in response to the grip ON signal or grip OFF signal, and controls the opening degree of the solenoid valve. As a result, pilot pressure acts on the pressure receiving part of the first control valve V71, and the position of the first control valve V71 is switched, and the gripping part 112 (a pair of gripping claws 121) becomes either closed (gripping the pipe W1) or open (not gripping the pipe W1) depending on the position.

[0066] The mode setting button 5e is a dial switch located on the top of the operating lever 5b, and according to the operator's operation, one of the normal work mode or the constant posture mode is selected. The control device 51 receives a mode signal indicating the mode selected by the mode setting button 5e. The normal work mode is a mode in which the boom 21, arm 22, and work tool T (e.g., attachment 100) can be operated in the normal manner. The constant posture mode is a mode in which the work tool T can be moved in a straight line while maintaining a constant posture (constant relative angle with respect to the horizontal plane) by operating the boom 21 or arm 22. The mode setting button 5e may be any other type of button or switch besides the dial switch. The positions of the gripping button 5a and the mode setting button 5e are not limited to the positions described above, but it is preferable to position them so that they can be operated with any finger of the hand gripping the operating lever 5b while performing a swinging operation on the operating lever 5b.

[0067] As shown in Figures 2A and 2B, the work machine 1 is equipped with a display device 70. The display device 70 has a display unit 71 and is capable of displaying information related to the work machine 1 and surrounding information. The display unit 71 is made up of a panel such as a liquid crystal display. Figure 3 is a diagram showing an example of the display of the display device 70. When the control device 51 receives an instruction to display the work status screen, it causes the display unit 71 to display the screen shown in Figure 3. As shown in Figure 3, the display unit 71 displays an image showing the work status of the work machine 1.

[0068] When either the normal work mode or the fixed posture work mode is selected by the mode setting button 5e, the display unit 71 displays the selected mode. In Figure 3, the display unit 71 displays a marker 71a indicating that the mode has been selected in the position corresponding to the "fixed posture" item field (for example, to the left) and displays a message M1 indicating that the fixed posture work mode is selected. If the normal work mode is selected, the display unit 71 displays a marker 71a indicating that the mode has been selected in the position corresponding to the "normal work" item field and displays a message M1 indicating that the normal work mode is selected.

[0069] As shown in Figure 2A, the control device 51 is connected to a first setting member 61 and a second setting member 62. The first setting member 61 is a member that accepts selections regarding the rotational speed setting of the prime mover E1 (a member that sets the rotational speed of the prime mover E1). The second setting member 62 is a member that accepts selections regarding the speed setting of the hydraulic actuator (a member that sets the speed of the hydraulic actuator). The control device 51 includes a rotational speed control unit 55, a speed control unit 56, and a storage unit 54.

[0070] The rotational speed control unit 55 is composed of a CPU (processor), electronic and electrical circuits, a program, etc., provided in the control device 51. The rotational speed control unit 55 sets the rotational speed of the prime mover E1 based on the operation signal of the first setting member 61. That is, the rotational speed control unit 55 increases or decreases the rotational speed of the prime mover E1 based on the operation of the first setting member 61.

[0071] The speed control unit 56 is composed of a CPU (processor), electronic and electrical circuits, and a program provided in the control device 51, and sets the work speed based on operation signals input from the first setting member 61 and the second setting member 62. Based on the work speed read from the storage unit 54, the speed control unit 56 energizes the solenoid valves of the control valves V1 to V10 with control signals corresponding to the operation amounts of the work operation members 19L, 19R, and 19D, thereby controlling the control valves V1 to V10. Specifically, the speed control unit 56 controls the maximum speed of the hydraulic actuators connected to each control valve V1 to V10 by changing the opening degree of the control valves V1 to V10.

[0072] Here, we will explain the work machine coordinate system. As shown in Figures 1A and 1B, the work machine coordinate system is a three-dimensional coordinate system (Xm, Ym, Zm) for the work machine 1. In this embodiment, the origin position PL1 of the work machine coordinate system is the intersection of axis Zm, which is the rotational axis of the machine body 2, and a plane perpendicular to axis Zm within the swing circle of the machine body 2, but is not limited to this. Axis Ym is an axis that extends in the front-rear direction of the machine body 2 and is perpendicular to axis Zm. Axis Ym is the reference axis in the front-rear direction of the machine body 2. Axis Xm is an axis that extends in the width direction of the machine body 2 and is perpendicular to axes Zm and Ym.

[0073] As shown in Figure 2B, the work machine 1 is equipped with a first sensing device 81, a second sensing device 82, and a position acquisition device 83, which are connected to the control device 51.

[0074] As shown in Figure 1A, the first sensing device 81 is provided on the attachment 100. The first sensing device 81 recognizes the position of the joint portion (i.e., the position of one end W1b of the pipe W1) of the joining member (pipe W1) that the attachment 100 is gripping, relative to the member to be joined (pipe W2). In this embodiment, the first sensing device 81 is a camera (for example, a CCD camera), but it may also be a LiDAR (Laser Imaging Detection and Ranging), TOF (Time Of Flight) camera, etc.

[0075] Furthermore, if the first sensing device 81 is a TOF camera or LiDAR, the position of one end W1b of the pipe W1 being gripped by the gripping part 112 can be detected by the distance measurement function. Note that the first sensing device 81 may be provided on the boom 21 or arm 22 instead of the attachment 100.

[0076] As shown in Figure 1A, the position acquisition device 83 acquires the position of the joint portion (one end W1b of pipe W1) of the joined member (joined pipe W2) to which it is joined (i.e., one end W2b of pipe W2). The position acquisition device 83 is, for example, a LiDAR, a TOF camera, or a camera (CCD camera), and is provided on the attachment 100. For example, the position acquisition device 83 is located in the same place as the first sensing device 81 (located side by side in close proximity). The position acquisition device 83 may be provided on the boom 21 or the arm 22 instead of the attachment 100.

[0077] The second sensing device 82 detects the orientation of the main body 30 and the attachment 100. The second sensing device 82 includes, for example, an inertial measurement unit (IMU) and a potentiometer. Alternatively, a cylinder stroke sensor may be used instead of the potentiometer.

[0078] The inertial measurement unit (IMU) is provided, for example, on the main body 30 and can determine the roll angle, pitch angle, and yaw angle of the work machine 1 (main body 30). The potentiometers are a boom angle sensor 91, an arm angle sensor 92, a work tool angle sensor 93, and a swing angle sensor 94, and are provided at various positions on the work device 20 or the machine body 2.

[0079] As shown in Figure 1A, the boom angle sensor 91 detects the swing angle θ2 (rotation position) of the boom 21. The arm angle sensor 92 detects the swing angle θ3 (rotation position) of the arm 22. The tool angle sensor 93 detects the swing angle θ4 (rotation position) of the attachment 100 (or bucket) around the third rotation axis J3 relative to the tip of the arm 22. The swing angle sensor 94 detects the swing angle θ1 (rotation position) of the swing bracket 24 (see Figure 1B for swing angle θ1). As shown in Figure 2A, the boom angle sensor 91, arm angle sensor 92, tool angle sensor 93, and swing angle sensor 94 are connected to the control device 51.

[0080] For example, the oscillation angle θ2 is the angle between the horizontal plane of the work machine 1 including the first rotation axis J1 and the straight line connecting the first rotation axis J1 and the second rotation axis J2 (a straight line with a length L11 of the boom 21). The oscillation angle θ3 is the angle between the straight line connecting the first rotation axis J1 and the second rotation axis J2 (a straight line with a length L11 of the boom 21) and the straight line connecting the second rotation axis J2 and the third rotation axis J3 (a straight line with a length L12 of the arm 22). The oscillation angle θ4 is the angle between the straight line connecting the second rotation axis J2 and the third rotation axis J3 (a straight line with a length L12 of the arm 22) and the reference line of the attachment 100.

[0081] The work machine 1 uses potentiometers as boom angle sensor 91, arm angle sensor 92, work tool angle sensor 93, and swing angle sensor 94, but is not limited to these. For example, the work machine 1 may use a cylinder stroke sensor to detect the stroke (extended position) of the boom cylinder C1, arm cylinder C9, attachment swing cylinder C2, and swing cylinder C4, and calculate the swing angles θ1 to θ4 of the boom 21, arm 22, attachment 100 (or bucket), and swing bracket 24 from the detection results.

[0082] The memory unit 54 stores data related to the work implement 1 (work implement data). The work implement data includes the length L11 of the boom 21, the length L12 of the arm 22, the length L13 of the attachment 100, and the length L14 of the swing bracket 24, as shown in Figure 1A. The length L11 of the boom 21 corresponds to the length from the first rotation axis J1 to the second rotation axis J2. The length L12 of the arm 22 corresponds to the length from the second rotation axis J2 to the third rotation axis J3. The length L13 of the attachment 100 corresponds to the length from the third rotation axis J3 to the origin position PL2 of the attachment 100. The length L14 of the swing bracket 24 corresponds to the length from the first rotation axis J1 to the pivot center of the swing bracket 24. Furthermore, the work machine data includes information on the position of the swing bracket 24 from the origin position PL1 of the work machine coordinate system (e.g., the pivot axis position) to the rotation center, and information on the position of the attachment 100 from the origin position PL2 to the tip position PR of the gripping part 112 in the axial direction. The tip position PR of the gripping part 112 is the tip closest to the joining function part 115. The control device 51 can determine the tip position PR of the gripping part 112 relative to the origin position PL1 using the lengths L11, L12, L13, L14, the position information, the swing angles θ1, θ2, θ3, θ4, and the origin positions PL1, PL2. In other words, it can determine the tip position PR of the gripping part 112 in the work machine coordinate system.

[0083] Furthermore, if the swing bracket 24 is fixed to axis Ym (in the front-rear direction of the machine body 2) or if the work machine 1 does not have a swing function, the control device 51 can use the lengths L11, L12, L13, position information (however, instead of information on the position of the swing bracket 24 to the rotation center relative to the origin position PL1 of the work machine coordinate system, information on the position to the first rotation axis J1 relative to the origin position PL1 of the work machine coordinate system is used), swing angles θ1, θ2, θ3 and origin positions PL1, PL2 to determine the tip position PR of the gripping part 112 relative to the origin position PL1.

[0084] More specifically, the first sensing device 81 recognizes the position of one end W1b of the pipe W1 gripped by the attachment 100, that is, its position relative to the first sensing device 81. Alternatively, the first sensing device 81 may recognize the position of the end W1b in the work machine coordinate system based on position information from the origin PL2 shown in Figure 1 to the first sensing device 81, position information from the first sensing device 81 to the end W1b, and the work machine coordinate system.

[0085] Furthermore, the position acquisition device 83 recognizes the position of one end W2b of the pipe to be joined W2, that is, its position in the coordinate system of the position acquisition device 83 (which is approximately the same as the coordinate system of the first sensing device 81). Alternatively, the position of one end W2b of the pipe to be joined W2 in the work machine coordinate system may be recognized based on the position information from the origin position PL2 shown in Figure 1 to the position acquisition device 83, the position information from the position acquisition device 83 to the end W2b, and the work machine coordinate system.

[0086] Now, in constant posture mode, the control device 51 rotates the boom 21, arm 22, and work tool T in response to the rotation operation of the boom 21 or arm 22 so that the work tool T (attachment 100) moves linearly (for example, horizontally or vertically) while maintaining a constant posture.

[0087] Figure 4 is an explanatory diagram showing how to move the work tool T horizontally in a constant posture. For example, in constant posture mode, the control device 51 rotates the arm 22 in response to the rotation operation of the arm 22, as shown in Figure 4, and also rotates the boom 21 and the work tool T so that the work tool T is moved horizontally in a constant posture. When the first instruction unit 17L (arm button) is operated, the control device 51 moves the work tool T horizontally in a constant posture in response to the swing operation of the arm operating member 19LA. In other words, only the arm 22 is rotated manually by the operator, while the boom 21 and the work tool T are rotated under automatic control by the control device 51. That is, the swing angle θ3 of the arm 22 is changed by manual operation, and the swing angle θ2 of the boom 21 and the swing angle θ4 of the work tool T are changed under automatic control.

[0088] Figure 5 is an explanatory diagram showing the vertical movement of the work tool T in a constant posture. In the constant posture mode, the control device 51 rotates the boom 21 in response to the rotation operation of the boom 21, as shown in Figure 5, and also rotates the arm 22 and the work tool T to move the work tool T vertically in a constant posture. When the second instruction unit 17R (boom button) is operated, the control device 51 moves the work tool T vertically in a constant posture in response to the swing operation of the boom operating member 19RB. In other words, only the boom 21 is rotated manually by the operator, while the arm 22 and the work tool T are rotated under automatic control by the control device 51. That is, the swing angle θ2 of the boom 21 is changed by manual operation, and the swing angle θ3 of the arm 22 and the swing angle θ4 of the work tool T are changed under automatic control.

[0089] Figure 6 shows an example of the calculation of the horizontal movement range HMR. As shown in Figure 6, the control device 51 calculates the current position PP, which is the coordinate position (e.g., tip position PR) of the work tool T at the present time in a three-dimensional coordinate system (e.g., work tool coordinate system), calculates the horizontal line HL that includes the current position PP, and calculates the horizontal movement range HMR in which the work tool T can move while maintaining a constant posture on the horizontal line HL.

[0090] As shown in Figure 6, the control device 51 calculates the furthest coordinate position FP, which is the furthest position the work tool T can be located on the horizontal line HL from the machine body 2. The control device 51 also calculates the nearest coordinate position CP, which is the closest position the work tool T can be located on the horizontal line HL to the machine body 2. The calculation order of the furthest coordinate position FP and the nearest coordinate position CP may be reversed, or they may be calculated simultaneously in parallel. Note that the × marks in Figure 6 indicate positions on the horizontal line HL where the work tool T cannot or should not be located. The control device 51 defines the range from the furthest coordinate position FP to the nearest coordinate position CP on the horizontal line HL as the horizontal movement range HMR.

[0091] The control device 51 may display the horizontal movement range HMR and the current position PP of the work tool T on the display unit 71 shown in Figure 3, etc. This allows the operator to know the horizontal movement range HMR and the current position PP of the work tool T within the horizontal movement range HMR in advance before moving the work tool T horizontally while maintaining a constant posture.

[0092] The control device 51 calculates the target position of the work tool T within the horizontal movement range HMR from the current position PP in response to the rotation operation of the arm 22, calculates the target rotational positions of the boom 21, arm 22, and work tool T when the work tool T is in the target position with a constant posture, and drives the boom 21, arm 22, and work tool T to their respective target rotational positions.

[0093] Figure 7 shows an example of the calculation of the vertical movement range VMR. As shown in Figure 7, the control device 51 calculates the current position PP, which is the coordinate position (e.g., tip position PR) of the work tool T at the present time in a three-dimensional coordinate system (e.g., work tool coordinate system), calculates a vertical line VL that includes the current position PP, and calculates the vertical movement range VMR in which the work tool T can move while maintaining a constant posture along the vertical line VL.

[0094] As shown in Figure 7, the control device 51 calculates the highest coordinate position HP at which the work tool T can move to the highest position on the vertical line VL. The control device 51 also calculates the lowest coordinate position LP at which the work tool T can move to the lowest position on the vertical line VL. The calculation order of the highest coordinate position HP and the lowest coordinate position LP may be reversed, or they may be calculated simultaneously in parallel. Note that the × marks shown in Figure 6 indicate positions on the vertical line VL where the work tool T cannot or should not be positioned. The control device 51 defines the range from the highest coordinate position HP to the lowest coordinate position LP on the vertical line VL as the vertical movement range VMR.

[0095] The minimum coordinate position LP can be changed depending on the positional relationship of the attachment 100 to the target area (for example, the groove G). When the attachment 100 is located above the groove G, the control device 51 calculates the minimum coordinate position LP by considering the position up to the depth of the groove G (the bottom position of the groove G). On the other hand, when the attachment 100 is not located above the groove G, the control device 51 calculates the minimum coordinate position LP by considering the position up to the ground. Whether or not the attachment 100 is located above the groove G can be determined based on the detected value from the first sensing device 81 or the position acquisition device 83.

[0096] The control device 51 may display the vertical movement range VMR and the current position PP of the work tool T on the display unit 71 shown in Figure 3, etc. This allows the operator to know the vertical movement range VMR and the current position PP of the work tool T within the vertical movement range VMR in advance before moving the work tool T vertically while maintaining a constant posture.

[0097] The control device 51 calculates the target position of the work tool T within the vertical movement range VMR from the current position PP in response to the rotation operation of the boom 21, calculates the target rotational positions of the boom 21, arm 22, and work tool T when the work tool T is in the target position with a constant posture, and drives the boom 21, arm 22, and work tool T to the target rotational positions.

[0098] The work machine 1 can set a posture that keeps the work tool T constant, that is, it can set the posture of the work tool T. Figure 8 shows an example of the display on the display device 70. When the control device 51 receives a command to display the posture setting screen for the work tool T, it displays the screen shown in Figure 8 on the display unit 71. As shown in Figure 8, the display unit 71 displays the work tool posture setting message M2 and displays the items for the current posture, horizontal posture and power-on posture.

[0099] The "Current Position" item indicates that the position of the work tool T remains constant during rotational operation of the boom 21 or arm 22. The "Horizontal Position" item indicates that the work tool T remains horizontal to the ground. The "Power-On Position" item indicates that the position of the work tool T is maintained when the power is turned on.

[0100] In Figure 8, the display unit 71 displays message M2 indicating that the horizontal posture is set when the marker 71a is in the position corresponding to the "horizontal posture" item field (for example, the left side) due to a selection operation by the operator. The control device 51 maintains the work tool T horizontal to the ground. For example, the second sensing device 82 (IMU) can detect the posture of the main body 30. Based on the detection value of the second sensing device 82, the control device 51 detects the slope of the ground on which the work machine 1 is located, stores the horizontal posture of the work tool T parallel to the ground, and maintains that posture constant.

[0101] If marker 71a is in the position corresponding to the "Current Position" field, message M2 is displayed to indicate that the current position is set. The control device 51 stores the position of the work tool T during the rotation operation of the boom 21 or arm 22 (for example, immediately before the rotation operation) and maintains that position constant.

[0102] If marker 71a is in the position corresponding to the "Power-on position" field, message M2 is displayed to indicate that the power-on position is set. The control device 51 stores the position of the work tool T when the power is turned on and maintains that position constant.

[0103] Figure 9 is a flowchart showing an example of setting the posture of the work tool T. As shown in Figure 9, the control device 51 determines whether or not there is an instruction to set the current posture (S11). If the marker 71a is in the position corresponding to the "current posture" item field due to a selection operation by the operator, the control device 51 determines that there is an instruction to set the current posture (Yes in S11), sets the posture at the time the boom 21 or arm 22 was rotated, that is, the current posture (S12), and stores it in the memory unit 54.

[0104] If the marker 71a is not in the position corresponding to the "Current Position" field due to a selection operation by the operator, the control device 51 determines that there is no instruction to set the current position (No in S11) and determines whether there is an instruction to set the horizontal position (S13). If the marker 71a is in the position corresponding to the "Horizontal Position" field due to a selection operation by the operator, the control device 51 determines that there is an instruction to set the horizontal position (Yes in S13), sets the horizontal position (S14), and stores it in the storage unit 54.

[0105] If the marker 71a is not in the position corresponding to the "horizontal posture" field due to a selection operation by the operator, the control device 51 determines that there is no instruction to set the horizontal posture (No in S13), and determines whether or not there is an instruction to set the posture when the power is turned on (S15). If the marker 71a is in the position corresponding to the "power-on posture" field due to a selection operation by the operator, the control device 51 determines that there is an instruction to set the posture when the power is turned on (Yes in S15), sets the posture when the power is turned on (S16), and stores it in the storage unit 54.

[0106] The control device 51 terminates this process after S12, after S14, after S16, or if it determines that there is no instruction to set the posture when the power is turned on (No in S15).

[0107] Here, we will explain linear motion control, which involves moving the work tool T in a straight line while maintaining a constant posture using the work machine 1, with reference to Figure 10. Figure 10 is a flowchart showing an example of linear motion control for moving the work tool T in a straight line while maintaining a constant posture.

[0108] As shown in Figure 10, the control device 51 determines whether or not the constant posture mode is active (S1). If the normal work mode is selected using the mode setting button 5e (normal work is displayed on the display unit 71 shown in Figure 3), the control device 51 determines that it is in normal work mode (No in S1) and performs normal movement control (S7). In other words, the control device 51 drives the boom 21 in response to the operation of the boom operating member 19RB, drives the arm 22 in response to the operation of the arm operating member 19LA, and drives the work tool T in response to the operation of the work tool operating member.

[0109] On the other hand, if the constant posture mode is selected using the mode setting button 5e (the display unit 71 shown in Figure 3 displays "constant posture"), the control device 51 determines that it is in constant posture mode (Yes in S1) and determines whether the first instruction unit 17L (arm button) is ON or OFF (S2).

[0110] If the first instruction unit 17L (arm button) is ON (Yes in S2), the control device 51 performs horizontal movement control (S3). The horizontal movement control (S3) is performed according to the flowchart shown in Figure 11. Figure 11 is a flowchart of an example of horizontal movement control.

[0111] As shown in Figure 11, the control device 51 calculates the current position PP, which is the coordinate position of the work tool T at the moment in the work tool coordinate system (for example, the tip position PR) (S31). The control device 51 calculates the horizontal line HL that includes the current position PP (S32). The control device 51 calculates the horizontal movement range HMR, which is the range in which the work tool T can move while maintaining a constant posture on the horizontal line HL (S33).

[0112] The control device 51 determines whether or not the work operating member 19L is swung in the forward and backward direction, that is, whether or not the arm operating member 19LA is swung (S34). If the control device 51 does not swung the arm operating member 19LA (No in S34), it returns to S34 and waits until the arm operating member 19LA is swung.

[0113] If the control device 51 detects a swinging operation of the arm operating member 19LA (Yes in S34), it moves the work tool T horizontally while maintaining a constant posture (S35). At this time, as shown in Figure 3, the display unit 71 displays "Constant Posture Horizontal Movement". For example, the display unit 71 displays the marker 71a at the position corresponding to the item field for "Constant Posture Horizontal Movement", indicating that it is in constant posture work mode and moving horizontally.

[0114] The control device 51 calculates the target position of the work tool T within the horizontal movement range HMR from the current position PP in response to the rotational operation of the arm operating member 19LA. For example, the target position is calculated in proportion to the amount of operation of the arm operating member 19LA. If the arm operating member 19LA is swung forward or backward and the amount of operation of the swing is the maximum amount, the control device 51 calculates the target position as the furthest coordinate position FP or the nearest coordinate position CP within the horizontal movement range HMR. Alternatively, if the arm operating member 19LA is swung forward or backward and the amount of operation of the swing is half of the maximum amount, the control device 51 calculates the target position as the halfway point from the current position PP to the furthest coordinate position FP or the nearest coordinate position CP within the horizontal movement range HMR. The control device 51 may also calculate the target position according to the operating speed instead of the amount of operation.

[0115] The control device 51 calculates the target swing angles for the boom 21, arm 22, and work tool T as target rotational positions when the work tool T is in a constant position at the target position, and drives the arm drive device (arm cylinder C9), boom drive device (boom cylinder C1), and work tool drive device (attachment swing cylinder C2) to move the boom 21, arm 22, and work tool T to their respective target swing angles.

[0116] In the above, the control device 51 calculates only the target position of the work tool T within the horizontal movement range HMR, but it may further calculate one or more intermediate point positions up to the target position. The control device 51 calculates the swing angle of each intermediate point as the rotation position of each intermediate point for the boom 21, arm 22, and work tool T for each of the intermediate point positions while the work tool T maintains a constant posture, and drives the arm drive device (arm cylinder C9), boom drive device (boom cylinder C1), and work tool drive device (attachment swing cylinder C2) so that the boom 21, arm 22, and work tool T reach each intermediate point swing angle, or it may drive the arm drive device (arm cylinder C9), boom drive device (boom cylinder C1), and work tool drive device (attachment swing cylinder C2) so that the boom 21, arm 22, and work tool T reach each target swing angle. In this case, the posture of the work tool T is kept constant at one or more intermediate points within the horizontal movement range HMR and at the target position, so that the posture of the work tool T can be kept constant and moved horizontally with greater precision.

[0117] Returning to S2 in Figure 10, if the first instruction unit 17L (arm button) is not ON (No in S2), the control device 51 determines whether the second instruction unit 17R (boom button) is ON or not (S4). If the second instruction unit 17R (boom button) is ON, the control device 51 performs vertical movement control (S5). Vertical movement control (S5) is performed according to the flowchart shown in Figure 12. Figure 12 is a flowchart of an example of vertical movement control.

[0118] As shown in Figure 12, the control device 51 calculates the current position PP, which is the coordinate position of the work tool T at the moment in the work tool coordinate system (for example, the tip position PR) (S51). The control device 51 calculates the vertical line VL that includes the current position PP (S52). The control device 51 calculates the vertical movement range VMR on the vertical line VL, which is the range in which the work tool T can move while maintaining a constant posture (S53).

[0119] The control device 51 determines whether or not the work operating member 19R is swung in the forward and backward direction, that is, whether or not the boom operating member 19RB is swung (S54). If the control device 51 does not swung the boom operating member 19RB (No in S54), it returns to S54 and waits until the boom operating member 19RB is swung.

[0120] If the boom operating member 19RB is oscillated (Yes in S54), the control device 51 moves the work tool T vertically while maintaining a constant posture (S55). At this time, as shown in Figure 3, the display unit 71 displays "Constant Posture Vertical Movement". For example, the display unit 71 displays the marker 71a at the position corresponding to the item field for "Constant Posture Vertical Movement", indicating that the operation is in constant posture mode and moving vertically.

[0121] The control device 51 calculates the target position of the work tool T within the vertical movement range VMR from the current position PP in response to the rotational operation of the boom operating member 19RB. For example, the target position is calculated in proportion to the amount of operation of the boom operating member 19RB. If the boom operating member 19RB is swung forward or backward and the amount of operation of the swing is the maximum amount, the control device 51 calculates the highest coordinate position HP or the lowest coordinate position LP of the vertical movement range VMR as the target position. Alternatively, if the boom operating member 19RB is swung forward or backward and the amount of operation of the swing is half of the maximum amount, the control device 51 calculates the target position as half the distance from the current position PP to the highest coordinate position HP or the lowest coordinate position LP of the vertical movement range VMR. The control device 51 may also calculate the target position according to the operating speed instead of the amount of operation.

[0122] The control device 51 calculates the target swing angles for the boom 21, arm 22, and work tool T as target rotational positions when the work tool T is in a constant position at the target position, and drives the arm drive device (arm cylinder C9), boom drive device (boom cylinder C1), and work tool drive device (attachment swing cylinder C2) to move the boom 21, arm 22, and work tool T to their respective target swing angles.

[0123] In the above, the control device 51 calculates only the target position of the work tool T within the vertical movement range VMR, but it may further calculate one or more intermediate point positions up to the target position. The control device 51 calculates the swing angle of each intermediate point as the rotation position of each intermediate point for the boom 21, arm 22, and work tool T for each of the intermediate point positions while the work tool T maintains a constant posture, and drives the arm drive device (arm cylinder C9), boom drive device (boom cylinder C1), and work tool drive device (attachment swing cylinder C2) so that the boom 21, arm 22, and work tool T reach each intermediate point swing angle, and may drive the arm drive device (arm cylinder C9), boom drive device (boom cylinder C1), and work tool drive device (attachment swing cylinder C2) so that the boom 21, arm 22, and work tool T reach each target swing angle. In this case, the posture of the work tool T is kept constant at one or more intermediate points within the vertical movement range VMR and at the target position, so the constant posture of the work tool T can be maintained with higher precision and moved vertically.

[0124] Returning to Figure 10, after S3 or after S5, the control device 51 determines whether the constant posture mode has ended (S6). If the constant posture mode is selected using the mode setting button 5e, the control device 51 determines that the constant posture mode has not ended (No in S6) and returns to S2. On the other hand, if the normal work mode is selected using the mode setting button 5e, the control device 51 determines that the constant posture mode has ended (Yes in S6).

[0125] The control method for the work machine 1 shown in Figure 10 includes control steps (S3, S5) in which the control device 51 rotates the boom 21, arm 22, and work tool T in response to the rotation operation of the boom 21 or arm 22 so that the work tool T moves in a straight line while maintaining a constant posture, when in constant posture mode.

[0126] Here, we will explain the drive control in the case of irregular operation using Figures 13A and 14A. First, we will explain the drive control in Figure 13A. The control device 51, when (i) there is no instruction to the second instruction unit 17R (boom button) and there is an instruction to the first instruction unit 17L (arm button), and there is a swinging operation of the boom operating member 19RB, will not accept the instruction to the first instruction unit 17L (arm button) and will rotate the boom 21 without keeping the working tool T in a constant position.

[0127] Figure 13A is a flowchart showing an example of drive control when the arm button is ON and boom operation is performed. As shown in Figure 13A, the control device 51 determines that the second instruction unit 17R (boom button) is OFF (Yes in S71) and that the first instruction unit 17L (arm button) is ON (Yes in S72), and then determines whether or not to perform boom operation (S73).

[0128] If the boom operating member 19RB is oscillating, i.e., the boom is being operated (Yes in S73), the control device 51 ignores the ON status of the first instruction unit 17L (arm button) (S74) and drives the boom 21 normally. In other words, if the second instruction unit 17R (boom button) corresponding to the boom operating member 19RB is OFF, it ignores the ON status of the other first instruction unit 17L (arm button) and performs normal boom driving.

[0129] Next, the drive control shown in Figure 14A will be explained. (ii) When there is no instruction to the first instruction unit 17L (arm button) and there is an instruction to the second instruction unit 17R (boom button), and the arm operating member 19LA is oscillating, the control device 51 does not accept the instruction to the second instruction unit 17R (boom button) and rotates the arm 22 without keeping the working tool T in a constant position.

[0130] Figure 14A is a flowchart showing an example of drive control when the boom button is ON and the arm is being operated. As shown in Figure 14A, the control device 51 determines that the first instruction unit 17L (arm button) is OFF (Yes in S81) and that the second instruction unit 17R (boom button) is ON (Yes in S82), and then determines whether or not the arm is being operated (S83).

[0131] If the control device 51 detects that the arm operating member 19LA is being swung, i.e., the arm is being operated (Yes in S83), it ignores the ON status of the second instruction unit 17R (boom button) (S84) and drives the arm 22 normally. In other words, if the first instruction unit 17L (arm button) corresponding to the arm operating member 19LA is OFF, it ignores the ON status of the other second instruction unit 17R (boom button) and performs normal arm driving.

[0132] Next, we will explain other examples of drive control in the case of irregular operation using Figures 13B and 14B. First, we will explain the drive control in Figure 13B.

[0133] Figure 13B is a flowchart showing another example of drive control when the arm button is ON and boom operation is enabled. Figure 13B differs from Figure 13A in that S74A and S75A are used instead of S74A and S75A. Therefore, S74A and S75A in Figure 13B will be explained below.

[0134] (iii) When there is no instruction to the second instruction unit 17R (boom button) and there is an instruction to the first instruction unit 17L (arm button), and the boom operating member 19RB is oscillating, the control device 51 accepts the instruction to the first instruction unit 17L (arm button) and rotates the boom 21 while keeping the work tool T in a constant position.

[0135] As shown in Figure 13B, if the boom operating member 19RB is oscillated, i.e., the boom is operated (Yes in S73), the control device 51 maintains a constant position for the work tool T (S74A) and drives the boom 21 with the work tool T in a constant position (S75A). At this time, since the arm operating member 19LA is not operated, the arm 22 is not driven. In other words, if the second instruction unit 17R (boom button) corresponding to the boom operating member 19RB is OFF, but the other first instruction unit 17L (arm button) is ON, the boom is driven with the work tool T in a constant position.

[0136] Figure 14B is a flowchart showing another example of drive control when the boom button is ON and the arm is being operated. Figure 14B differs from Figure 14A in that S84A and S85A are replaced with S84A and S85A. Therefore, S84A and S85A in Figure 14B will be explained below.

[0137] (iv) When there is no instruction to the first instruction unit 17L (arm button) and there is an instruction to the second instruction unit 17R (boom button), and the arm operating member 19LA is swung, the control device 51 accepts the instruction to the second instruction unit 17R (boom button) and rotates the arm 22 while keeping the working tool T in a constant position.

[0138] As shown in Figure 14B, if the control device 51 detects a swing operation of the arm operating member 19LA, i.e., an arm operation (Yes in S83), it sets the working tool T to a constant position (S84A) and drives the arm 22 (S85A). At this time, since the boom operating member 19RB is not operated, the boom 21 is not driven. In other words, if the first instruction unit 17L (arm button) corresponding to the arm operating member 19LA is OFF, but the other second instruction unit 17R (boom button) is ON, the working tool T is set to a constant position and the arm is driven.

[0139] Furthermore, the control device 51 may (v) have instructions for both the first instruction unit 17L (arm button) and the second instruction unit 17R (boom button), and when the arm operating member 19LA is swung, move the work tool T horizontally while maintaining a constant posture, and when the boom operating member 19RB is swung, move the work tool T vertically while maintaining a constant posture.

[0140] By the way, in the above embodiment, we have described an example in which an operator (driver) riding on the work machine 1 rotates the boom 21 or arm 22 to move the work tool T in a straight line while maintaining a constant posture, but we are not limited to this. For example, it can also be applied to a remote control system SY that remotely controls the work machine 1.

[0141] Figure 15 is a block diagram showing the configuration of the remote control system SY. As shown in Figure 15, the remote control system SY comprises the above-mentioned work machine 1 and a remote control device 200 for remotely operating the work machine 1.

[0142] The remote control device 200 includes a remote control device 205 which is operated by a remote operator (operator). The remote control device 205 includes work operation members (work operation member 219L, work operation member 219R, work operation member 219D) and travel operation members (travel operation member 220L, travel operation member 220R).

[0143] The work operation members 219L, 219R, and 219D are remote operation members with the same configuration as the work operation members 19L, 19R, and 19D of the work machine 1. The travel operation members 220L and 220R are remote operation members with the same configuration as the travel operation members 20L and 20R of the work machine 1.

[0144] The work operation member 219L functions as an arm operation member 219LA when swung in the front-to-back direction, and as a swivel operation member when swung in the left-to-right direction. The work operation member 219L (arm operation member 219LA) is equipped with a first instruction unit 217L (e.g., an arm button) that is operated by the operator.

[0145] The work operation member 219R functions as a boom operation member 219RB when swung in the front-to-back direction, and as a work tool operation member when swung in the left-to-right direction. The work operation member 219R (boom operation member 219RB) is equipped with a second instruction unit 217R (e.g., a boom button) that is operated by the operator.

[0146] The remote control device 205 includes a mode indicator unit 205e that instructs the control device 51 to enter the constant posture mode. The mode indicator unit 205e is a remote operating member with a configuration similar to the mode setting button 5e of the work machine 1. The mode indicator unit 205e selects either the normal work mode or the constant posture mode according to the operation of the remote operator.

[0147] The remote control device 200 includes a control device 251, a display device 270, and a communication device 275. The control device 251 is a processor that controls the operation of each part of the remote control device 200. This processor controls the operation of each part of the remote control device 200, for example, by executing a pre-stored remote control program.

[0148] The display device 270 is, for example, a liquid crystal display or an organic EL display. The display device 270 displays captured images of the area around the work machine 1, and various information for remotely operating the work machine 1.

[0149] The communication device 275 communicates wirelessly with the work machine 1. The communication device 275 consists of an antenna, an IC (integrated circuit), and electrical circuits for wireless communication via a mobile phone network, the internet, or a wireless LAN.

[0150] The work machine 1 is equipped with a communication device 75. The communication device 75 communicates wirelessly with the remote device 200. The communication device 75 consists of an antenna, an IC (integrated circuit), and electrical circuits for wireless communication via a mobile phone network, the internet, or a wireless LAN.

[0151] The control device 251 of the remote device 200 remotely instructs the work machine 1 when the remote operator operates the mode indicator unit 205e to enter constant posture mode. The control device 251 calculates the horizontal movement range HMR based on the operation of the first indicator unit 217L (arm button) and calculates the vertical movement range VMR based on the operation of the second indicator unit 217R (boom button). In constant posture mode, the control device 251 remotely instructs the boom 21, arm 22 and work tool T to rotate in response to the rotation operation of the boom operating member 219RB or arm operating member 219LA, so that the work tool T (attachment 100) moves linearly (for example, horizontally or vertically) while maintaining a constant posture. In the remote control system SY, the control device 51 of the work machine 1 may perform some or all of the calculations performed by the control device 251.

[0152] The main characteristic features and effects of the control device 51, the work machine 1, the remote control system SY, and the control method for the work machine 1 in the embodiments described above are as follows.

[0153] (Item A1) A control device 51 for a work machine 1 comprising a machine body 2, a boom 21 whose base end is supported by the machine body 2 so as to be rotatable around a first rotation axis J1, an arm 22 whose base end is supported at the tip of the boom 21 so as to be rotatable around a second rotation axis J2, and a work tool T supported at the tip of the arm 22 so as to be rotatable around a third rotation axis J3, wherein in constant posture mode, the control device 51 rotates the boom 21, the arm 22, and the work tool T in response to rotational operation of the boom 21 or the arm 22 so as to move the work tool T in a straight line while maintaining a constant posture.

[0154] With this configuration, in constant posture mode, the operator only needs to rotate either the boom 21 or the arm 22, and the control device 51 can move the work tool T of the work machine 1 in a straight line while maintaining a constant posture. Therefore, the operator does not need to perform the difficult operation of rotating both the arm 22 and the boom 21 to move the work tool T in a straight line while maintaining a constant posture. As a result, the operator can easily perform the operation of moving the work tool T in a straight line while maintaining a constant posture. Thus, the control device 51 can assist (support) the operation performed by the operator.

[0155] (Item A2) The control device 51 according to Item A1, which, in the constant posture mode, rotates the arm 22 in response to the rotation operation of the arm 22, and rotates the boom 21 and the work tool T so that the work tool T moves horizontally in a constant posture.

[0156] With this configuration, in constant-position mode, the operator only needs to rotate the arm 22, and the work machine 1 can move the work tool T horizontally while maintaining a constant position. Therefore, the operator does not need to perform the difficult operation of rotating both the arm 22 and the boom 21 to move the work tool T horizontally while maintaining a constant position. As a result, the operator can easily move the work tool T horizontally while maintaining a constant position. Thus, the control device 51 can assist (support) the operator's operation of moving the work tool T horizontally.

[0157] (Item A3) The control device 51 according to item A1 or A2, which, in the constant posture mode, rotates the boom 21 in response to the rotation operation of the boom 21, and rotates the arm 22 and the work tool T so as to move the work tool T vertically in a constant posture.

[0158] With this configuration, in constant posture mode, the operator only needs to rotate the boom 21, and the work machine 1 can move the work tool T vertically while maintaining a constant posture. Therefore, the operator does not need to perform the difficult operation of rotating both the arm 22 and the boom 21 to move the work tool T vertically while maintaining a constant posture. As a result, the operator can easily move the work tool T vertically while maintaining a constant posture. Thus, the control device 51 can assist (support) the operator's operation of moving the work tool T vertically.

[0159] (Item A4) The control device 51 described in Item A2, which calculates the current position PP, which is the coordinate position of the work tool T at the present time in a three-dimensional coordinate system, calculates a horizontal line HL that includes the current position PP, and calculates the horizontal movement range HMR on the horizontal line HL in which the work tool T can move while maintaining a constant posture.

[0160] With this configuration, the control device 51 can suitably acquire a horizontal movement range HMR that allows the work tool T to be moved horizontally from its current position PP while maintaining a constant posture.

[0161] (Item A5) A control device 51 according to Item A4, which calculates the target position of the work tool T within the horizontal movement range HMR from the current position PP in response to the rotation operation of the arm 22, calculates the target rotational positions of the boom 21, the arm 22, and the work tool T when the work tool T is in the target position with a constant posture, and drives the boom 21, the arm 22, and the work tool T to their respective target rotational positions.

[0162] With this configuration, the operator only needs to rotate the arm 22, and the work machine 1 can move the work tool T horizontally from its current position PP while maintaining a constant posture to reach the target position. Therefore, even an inexperienced operator can easily perform the horizontal movement operation.

[0163] (Item A6) A control device 51 according to item A4 or A5, which calculates the furthest coordinate position FP at which the work tool T can be positioned furthest from the machine body 2 on the horizontal line HL, calculates the nearest coordinate position CP at which the work tool T can be positioned closest to the machine body 2 on the horizontal line HL, and defines the horizontal movement range HMR as the range between the furthest coordinate position FP and the nearest coordinate position CP on the horizontal line HL.

[0164] With this configuration, the control device 51 can suitably calculate the horizontal movement range HMR of the work tool T at the current position PP, and can know the horizontal movement range HMR of the work tool T in advance.

[0165] (Item A7) The control device 51 described in Item A3, which calculates the current position PP, which is the coordinate position of the work tool T at the present time in a three-dimensional coordinate system, calculates a vertical line VL that includes the current position PP, and calculates the vertical movement range VMR on the vertical line VL in which the work tool T can move while maintaining a constant posture.

[0166] With this configuration, the control device 51 can suitably acquire the vertical movement range VMR, which allows the work tool T to be moved vertically from its current position PP while maintaining a constant posture.

[0167] (Item A8) A control device 51 according to Item A7, which calculates the target position of the work tool T within the vertical movement range VMR from the current position PP in response to the rotation operation of the boom 21, calculates the target rotation positions of the boom 21, the arm 22, and the work tool T when the work tool T is in the target position with a constant posture, and drives the boom 21, the arm 22, and the work tool T to the target rotation positions.

[0168] With this configuration, the operator only needs to rotate the boom 21, and the control device 51 can move the work tool T vertically from its current position PP while maintaining a constant posture to reach the target position. Therefore, even an inexperienced operator can easily perform the vertical movement operation.

[0169] (Item A9) A control device 51 according to Item A7 or A8, which calculates the highest coordinate position HP to which the work tool T can move to the highest position on the vertical line VL, calculates the lowest coordinate position LP to which the work tool T can move to the lowest position on the vertical line VL, and sets the range between the highest coordinate position HP and the lowest coordinate position LP on the vertical line VL as the vertical movement range VMR.

[0170] With this configuration, the control device 51 can suitably calculate the vertical movement range VMR of the work tool T and can know the vertical movement range VMR of the work tool T in advance.

[0171] (Item A10) A control device 51 according to any one of items A1 to A9 that maintains a constant posture of the work tool T when the boom 21 or the arm 22 is rotated.

[0172] With this configuration, the control device 51 can maintain the posture of the work tool T during rotational operation of the boom 21 or arm 22 and move the work tool T in a straight line (horizontal or vertical).

[0173] (Item A11) A control device 51 according to any one of items A1 to A9 that maintains the posture of the work tool T when the power of the work machine 1 is turned on.

[0174] With this configuration, the control device 51 can maintain the orientation of the work tool T when the power to the work machine 1 is turned on and move the work tool T in a straight line (horizontal or vertical). For example, the power to the work machine 1 may be turned off while the work tool T is in contact with the ground. Therefore, when the power to the work machine 1 is turned on, the work tool T is in a position where it is touching the ground, and in this position, the work tool T is parallel to the ground (i.e., horizontal). Therefore, the work machine 1 can maintain this orientation and move the work tool T in a straight line (horizontal or vertical).

[0175] (Item A12) A work machine 1 comprising a machine body 2, a boom 21 whose base end is supported by the machine body 2 so as to be rotatable around a first rotation axis J1, an arm 22 whose base end is supported at the tip of the boom 21 so as to be rotatable around a second rotation axis J2 parallel to the first rotation axis J1, a work tool T supported at the tip of the arm 22 so as to be rotatable around a third rotation axis J3 parallel to the first rotation axis J1, and a control device as described in any one of items A1 to A11.

[0176] In this configuration, in a work machine 1 where the rotation axes of the boom 21, arm 22, and work tool T (first rotation axis J1, second rotation axis J2, and third rotation axis J3) are parallel, in constant posture mode, the work machine 1 can move the work tool T in a straight line while maintaining a constant posture simply by the operator rotating either the boom 21 or the arm 22. Therefore, the operator does not need to perform the difficult operation of rotating both the arm 22 and the boom 21 to move the work tool T in a straight line while maintaining a constant posture. As a result, the operator can easily perform the operation of moving the work tool T in a straight line while maintaining a constant posture. Thus, the work machine 1 can assist (support) the operation performed by the operator.

[0177] (Item A13) The work machine 1 according to Item A12, comprising an arm operating member 19LA which is swung by an operator to operate the arm 22, and a first instruction unit 17L provided on the arm operating member 19LA and operated by an operator, wherein when the first instruction unit 17L is operated, the control device 51 moves the work tool T in a straight line while maintaining a constant posture in response to the swinging operation of the arm operating member 19LA.

[0178] With this configuration, the operator can move the work tool T in a straight line (for example, horizontally) while maintaining a constant posture simply by swinging the arm operating member 19LA, without swinging the boom operating member 19RB.

[0179] (Item A14) The work machine 1 according to Item A12, comprising a boom operating member 19RB which is swung by an operator to operate the boom 21, and a second instruction unit 17R provided on the boom operating member 19RB and operated by an operator, wherein when the second instruction unit 17R is operated, the control device 51 moves the work tool T in a straight line while maintaining a constant posture in response to the swinging operation of the boom operating member 19RB.

[0180] With this configuration, the operator can move the work tool T in a straight line (for example, vertically) while maintaining a constant posture simply by swinging the boom operating member 19RB, without swinging the arm operating member 19LA.

[0181] (Item A15) The work machine 1 according to Item A12, comprising: an arm operating member 19LA which is swung by an operator to operate the arm 22; a first instruction unit 17L provided on the arm operating member 19LA and operated by an operator; a boom operating member 19RB which is swung by an operator to operate the boom 21; and a second instruction unit 17R provided on the boom operating member 19RB and operated by an operator, wherein when the first instruction unit 17L is operated, the control device 51 moves the work tool T horizontally in a constant position in response to the swinging operation of the arm operating member 19LA, and when the second instruction unit 17R is operated, the work tool T moves vertically in a constant position in response to the swinging operation of the boom operating member 19RB.

[0182] With this configuration, the operator can move the work tool T horizontally while maintaining a constant posture simply by swinging the arm operating member 19LA, without swinging the boom operating member 19RB. Furthermore, the operator can move the work tool T vertically while maintaining a constant posture simply by swinging the boom operating member 19RB, without swinging the arm operating member 19LA.

[0183] (Item A16) The work machine 1 according to item A13 or A15, wherein the first instruction unit 17L is positioned so that it can be operated by the fingers of the hand that is gripping the arm operating member 19LA while the operator is gripping the arm operating member 19LA and swinging it.

[0184] With this configuration, the first instruction unit 17L (arm button), or assist button, can be operated with one hand while simultaneously performing the rocking motion with the same hand. This results in excellent operability.

[0185] (Item A17) The work machine 1 according to item A14 or A15, wherein the second instruction section 17R is provided in a position that can be operated by the fingers of the hand that is gripping the boom operating member 19RB while the operator is gripping the boom operating member 19RB and swinging it.

[0186] With this configuration, the second instruction unit 17R (boom button), or assist button, can be operated with one hand while simultaneously controlling the swing motion with the same hand. This results in superior operability.

[0187] (Item A18) The work tool T is an attachment 100 for gripping a long object W, as described in any one of Items A12 to A17.

[0188] With this configuration, in constant-position mode, the operator can rotate either the boom 21 or the arm 22, and the work machine 1 will move the work tool T (i.e., the attachment 100 for gripping a long object W) in a straight line while maintaining a constant position. Therefore, the operator can easily perform the operation of moving the long object W in a straight line while maintaining a constant position. Thus, the work machine 1 can assist (support) the operator's operation.

[0189] (Item A19) A remote control system SY comprising a work machine 1 described in any one of items A12 to A18, and a remote control device 200 for remotely controlling the work machine 1, wherein the remote control device 200 comprises a boom operating member 219RB that is oscillating, an arm operating member 219LA that is oscillating, and a mode indicator unit 205e that instructs the control device 51 to enter the constant posture mode.

[0190] With this configuration, the mode instruction unit 205e instructs the control device 51 of the remote work implement 1 to enter constant posture mode, and then the remote operator simply rotates either the boom operating member 219RB or the arm operating member 219LA, allowing the work implement 1 to move the work tool T in a straight line while maintaining a constant posture. Therefore, the remote operator does not need to perform the difficult operation of rotating both the arm 22 and the boom 21 to move the work tool T in a straight line while maintaining a constant posture. As a result, the remote operator can easily perform the operation of moving the work tool T in a straight line while maintaining a constant posture. Thus, the remote control system SY can assist (support) the remote operator in remotely controlling the work implement 1.

[0191] (Item A20) A control method for a work machine 1 comprising a machine body 2, a boom 21 whose base end is supported by the machine body 2 so as to be rotatable around a first rotation axis J1, an arm 22 whose base end is supported at the tip of the boom 21 so as to be rotatable around a second rotation axis J2, and a work tool T supported at the tip of the arm 22 so as to be rotatable around a third rotation axis J3, wherein in a constant posture mode, the control device 51 rotates the boom 21, the arm 22, and the work tool T in response to a rotation operation of the boom 21 or the arm 22 so as to move the work tool T in a straight line while maintaining a constant posture.

[0192] With this configuration, in constant-position mode, the operator can move the work tool T in a straight line while maintaining a constant position simply by rotating either the boom 21 or the arm 22. Therefore, the operator does not need to perform the difficult operation of rotating both the arm 22 and the boom 21 to move the work tool T in a straight line while maintaining a constant position. As a result, the operator can easily move the work tool T in a straight line while maintaining a constant position. Thus, the work tool 1 can assist (support) the operator's operation.

[0193] (Item A21) The control device 51, as described in Item A15, (i) when there is no instruction to the second instruction unit 17R and there is an instruction to the first instruction unit 17L and the boom operating member 19RB is swung, does not accept an instruction to the first instruction unit 17L and rotates the boom 21 without keeping the working tool T in a constant position, and (ii) when there is no instruction to the first instruction unit 17L and there is an instruction to the second instruction unit 17R and the arm operating member 19LA is swung, does not accept an instruction to the second instruction unit 17R and rotates the arm 22 without keeping the working tool T in a constant position.

[0194] With this configuration, if an instruction is given to the first instruction unit 17L, which is unrelated to the boom operating member 19RB, the instruction is not accepted (ignored), so the boom 21 can be driven normally. Also, if an instruction is given to the second instruction unit 17R, which is unrelated to the arm operating member 19LA, the instruction is not accepted (ignored), so the arm 22 can be driven normally.

[0195] (Item A22) The control device 51, as described in Item A15, (iii) when there is no instruction to the second instruction unit 17R and there is an instruction to the first instruction unit 17L and there is a swinging operation of the boom operating member 19RB, receives an instruction to the first instruction unit 17L and rotates the boom 21 while keeping the work tool T in a constant position, and (iv) when there is no instruction to the first instruction unit 17L and there is an instruction to the second instruction unit 17R and there is a swinging operation of the arm operating member 19LA, receives an instruction to the second instruction unit 17R and rotates the arm 22 while keeping the work tool T in a constant position.

[0196] With this configuration, when an instruction is given to the first instruction unit 17L, which is unrelated to the boom operating member 19RB, the instruction can be received, and the boom 21 can be driven while the working tool T maintains a constant position. Also, when an instruction is given to the second instruction unit 17R, which is unrelated to the arm operating member 19LA, the instruction can be received, and the arm 22 can be driven while the working tool T maintains a constant position.

[0197] (Item A23) The control device 51 (v) when instructions are given to both the first instruction unit 17L and the second instruction unit 17R, and when the arm operating member 19LA is swung, the work tool T is moved horizontally while maintaining a constant posture, and when the boom operating member 19RB is swung, the work tool T is moved vertically while maintaining a constant posture, as described in Item A15.

[0198] With this configuration, if both the first indicator unit 17L and the second indicator unit 17R are indicated, horizontal and vertical movement can be performed.

[0199] In the above embodiment, the constant posture mode is set using the mode setting button 5e, horizontal movement is set by operating the first instruction unit 17L (arm button), and vertical movement is set by operating the second instruction unit 17R (boom button), but the embodiment is not limited to this. For example, the constant posture mode and horizontal movement may be set by operating only the first instruction unit 17L (arm button), and the constant posture mode and vertical movement may be set by operating only the arm operating member 19LA.

[0200] In the above embodiment, the object to be gripped W is assumed to be a straight (long) pipe W1, but it may be a pipe of various shapes other than a straight pipe, such as a U-shape, S-shape, or L-shape, and all other items that can be gripped (for example, wood, iron rods, steel materials, parts, etc.) are included.

[0201] In the above embodiment, the control device 51 may move the work tool T linearly (for example, horizontally or vertically) while maintaining a constant posture, using not only the work tool coordinate system, but also the global coordinate system, the coordinate system of the work tool T, the coordinate system of the first sensing device 81, etc. It is possible to change the coordinate systems with each other using known coordinate transformation calculations.

[0202] In the above embodiment, the control device 51 is not limited to one that is initially provided with the work machine 1, but may be retrofitted to an existing (current) work machine 1. For example, a control device 51 having the function of moving in a straight line while maintaining a constant posture may be used to replace or add to an existing control device that does not have this function.

[0203] In the above embodiment, the work machine 1 is configured to drive the first hydraulic pump P1, the second hydraulic pump P2, and the third hydraulic pump P3 with the power of the prime mover E1. However, it may also be an electric type or a hybrid type equipped with a drive battery and an electric motor instead of or in addition to the prime mover E1. In this case, the work machine 1 drives an electric motor with power from the drive battery, drives the first hydraulic pump P1, the second hydraulic pump P2 and the third hydraulic pump P3 with the power of the electric motor, and drives the hydraulic actuators (boom cylinder C1, attachment swing cylinder C2, dozer cylinder C3, swing cylinder C4, arm cylinder C9), left-hand travel motor ML, right-hand travel motor MR and slewing motor MT with the hydraulic fluid discharged from the first hydraulic pump P1 and the second hydraulic pump P2, and drives the work device 20 and the travel device 10 with the power of the hydraulic actuators (boom cylinder C1, attachment swing cylinder C2, dozer cylinder C3, swing cylinder C4, arm cylinder C9), left-hand travel motor ML, right-hand travel motor MR and slewing motor MT.

[0204] Furthermore, the work machine 1 may be configured such that some or all of the actuators provided in the work device 20 and the travel device 10 are electric actuators, and these electric actuators are driven by battery power, thereby driving the work device 20 and the travel device 10. For example, in addition to a configuration in which all actuators are electric actuators, the work machine 1 may also be configured to have at least one electric motor for driving the hydraulic pump and an electric motor for slewing.

[0205] In the above embodiment, the work implement 1 is a model with a swing function, but it may also be a model without a swing device (swing cylinder C4), that is, a model without a swing function (such as an ultra-short swing machine). Furthermore, the work implement 1 may be a two-piece boom type, regardless of whether it has a swing function or not.

[0206] Having described the present invention above, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope of equivalents of the claims are intended to be included.

[0207] In the embodiments described above, examples of applying the present invention to a work machine 1 such as a backhoe were explained, but the application of the present invention is not limited to this, and it may also be applied to other construction machinery such as wheel loaders, compact track loaders, and skid steer loaders.

[0208] 1. Work machine 2. Machine body 17L First instruction unit (arm button) 17R Second instruction unit (boom button) 19RB Boom operating member 19LA Arm operating member 21 Boom 22 Arm 51 Control device 100 Attachment 200 Remote control device 219RB Boom operating member 219LA Arm operating member 205e Mode instruction unit C1 Boom cylinder (boom drive device) C2 Attachment oscillating cylinder (work tool drive device) C9 Arm cylinder (arm drive device) J1 First rotation axis J2 Second rotation axis J3 Third rotation axis SY Remote control system T Work tool W Gripping object (joining member)

Claims

1. A control device for a work machine comprising a machine body, a boom whose base end is supported by the machine body so as to be rotatable around a first rotation axis, an arm whose base end is supported by the tip of the boom so as to be rotatable around a second rotation axis, and a work tool supported by the tip of the arm so as to be rotatable around a third rotation axis, wherein, in constant posture mode, the control device rotates the boom, the arm, and the work tool in response to rotational operation of the boom or the arm so as to move the work tool in a straight line while maintaining a constant posture.

2. The control device according to claim 1, wherein, in the constant posture mode, the arm is rotated in response to the rotation operation of the arm, and the boom and the work tool are rotated so that the work tool is moved horizontally in a constant posture.

3. The control device according to claim 1, wherein, in the constant posture mode, the boom is rotated in response to the rotation operation of the boom, and the arm and the work tool are rotated so that the work tool is moved vertically in a constant posture.

4. The control device according to claim 2, which calculates the current position, which is the coordinate position of the work tool at the present time in a three-dimensional coordinate system, calculates a horizontal line including the current position, and calculates the horizontal movement range in which the work tool can move while maintaining a constant posture on the horizontal line.

5. The control device according to claim 4, which calculates a target position of the work tool within the horizontal movement range from the current position in response to the rotation operation of the arm, calculates the target rotational positions of the boom, the arm, and the work tool when the work tool is positioned at the target position with a constant posture, and drives the boom, the arm, and the work tool to their respective target rotational positions.

6. The control device according to claim 4, which calculates the furthest coordinate position at which the work tool can be positioned furthest from the machine on the horizontal line, calculates the nearest coordinate position at which the work tool can be positioned closest to the machine on the horizontal line, and defines the range between the furthest coordinate position and the nearest coordinate position on the horizontal line as the horizontal movement range.

7. The control device according to claim 3, which calculates the current position, which is the coordinate position of the work tool at the present time in a three-dimensional coordinate system, calculates a vertical line including the current position, and calculates the vertical movement range in which the work tool can move while maintaining a constant posture along the vertical line.

8. The control device according to claim 7, which calculates a target position of the work tool within the vertical movement range from the current position in response to the rotation operation of the boom, calculates the target rotation positions of the boom, the arm, and the work tool when the work tool is positioned at the target position with a constant posture, and drives the boom, the arm, and the work tool to the target rotation positions.

9. The control device according to claim 7, which calculates the highest coordinate position at which the work tool can move to the highest position on the vertical line, calculates the lowest coordinate position at which the work tool can move to the lowest position on the vertical line, and defines the range between the highest coordinate position and the lowest coordinate position on the vertical line as the vertical movement range.

10. The control device according to any one of claims 1 to 9, which maintains a constant posture of the work tool when the boom or arm is rotated.

11. A control device according to any one of claims 1 to 9, which maintains the posture of the work tool when the power of the work machine is turned on.

12. A work machine comprising: a machine body; a boom whose base end is supported by the machine body so as to be rotatable around a first rotation axis; an arm whose base end is supported by the tip of the boom so as to be rotatable around a second rotation axis; a work tool supported by the tip of the arm so as to be rotatable around a third rotation axis; and the control device described in claim 1.

13. The work machine according to claim 12, further comprising: an arm operating member which is swung by an operator to operate the arm; and a first indicator unit provided on the arm operating member and operated by an operator, wherein when the first indicator unit is operated, the control device moves the work tool in a straight line while maintaining a constant posture in response to the swinging operation of the arm operating member.

14. The work machine according to claim 12, further comprising: a boom operating member which is oscillated by an operator to operate the boom; and a second indicator unit provided on the boom operating member and operated by an operator, wherein when the second indicator unit is operated, the control device moves the work tool in a straight line while maintaining a constant posture in response to the oscillation operation of the boom operating member.

15. The work machine according to claim 12, comprising: an arm operating member which is swung by an operator to operate the arm; a first indicator provided on the arm operating member and operated by an operator; a boom operating member which is swung by an operator to operate the boom; and a second indicator provided on the boom operating member and operated by an operator, wherein when the first indicator is operated, the control device moves the work tool in a straight line while maintaining a constant posture in response to the swinging operation of the arm operating member, and when the second indicator is operated, the work tool moves in a straight line while maintaining a constant posture in response to the swinging operation of the boom operating member.

16. The work machine according to claim 13 or 15, wherein the first instruction unit is provided in a position that can be operated by the fingers of the hand that is gripping the arm operating member while the operator is gripping the arm operating member and swinging it.

17. The work machine according to claim 14 or 15, wherein the second indicator is provided in a position that can be operated by the fingers of the hand that is gripping the boom operating member while the operator is gripping the boom operating member and swinging it.

18. The work machine according to claim 12, wherein the work tool is an attachment for gripping a long object to be gripped.

19. A remote control system comprising: a work machine as described in claim 12; and a remote control device for remotely controlling the work machine, wherein the remote control device comprises: a boom operating member that is oscillating; an arm operating member that is oscillating; and a mode indicator unit that instructs the control device to enter the constant posture mode.

20. A control method for a work machine comprising a machine body, a boom whose base end is supported by the machine body so as to be rotatable about a first rotation axis, an arm whose base end is supported by the tip of the boom so as to be rotatable about a second rotation axis, and a work tool supported by the tip of the arm so as to be rotatable about a third rotation axis, wherein, in constant posture mode, the control device includes a control step of rotating the boom, the arm, and the work tool in response to a rotation operation of the boom or the arm so as to move the work tool in a straight line while maintaining a constant posture.

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