Control device

Abstract

In the present invention, a controller: acquires starting position information that is positional information relative to a target shape of a tracking control target portion at the start of tracking control; adjusts, on the basis of the starting position information, the target shape to the position of the tracking control target portion at the start or a position between the target shape and the tracking control target portion at the start; and adjusts the target shape so that an offset amount that is the difference between the target shape before being adjusted and the target shape after being adjusted approaches zero as attachment work proceeds under the tracking control.

Description

Control device

[0001] The present invention relates to a control device for controlling a work machine.

[0002] For example, Patent Document 1 describes a technique for controlling a work machine based on the distance between an attachment (called a work implement in the document) and a target shape (called a target construction terrain in the document) (see claim 1, etc. of the document). In this technique, the attachment is controlled so that it moves along the target shape (see Figures 6 and 7, etc. of the document).

[0003] However, as the attachment approaches the target shape and reaches the target shape, it may be necessary to abruptly change the movement of the attachment. However, it is difficult to accurately control the attachment to abruptly change its movement. As a result, it is difficult to accurately control the attachment so that it moves along the target shape.

[0004] Patent No. 6096988

[0005] An object of the present invention is to provide a control device that can accurately control an attachment so that the attachment moves along a target shape.

[0006] A control device according to one aspect of the present invention includes a controller capable of performing tracking control, which is control for automatically moving a specific tracking-controlled portion of an attachment of a work machine so that the attachment moves along a target shape. The controller acquires start position information, which is position information of the tracking-controlled portion relative to the target shape at the start of the tracking control, and corrects the target shape based on the start position information to the position of the tracking-controlled portion at the start or to a position between the tracking-controlled portion and the target shape at the start, and corrects the target shape so that an offset, which is the difference between the target shape before and after correction, approaches zero as work of the attachment progresses under the tracking control.

[0007] FIG. 1 is a side view of a work machine according to an embodiment of the present invention. FIG. 2 is a block diagram of a control device according to an embodiment of the present invention. FIG. 3 is a side view showing a corrected target shape and the like when the offset amount approaches 0 as the movement distance of the controlled portion of the work machine according to an embodiment of the present invention increases. FIG. 4 is a side view showing a corrected target shape and the like when the offset amount approaches 0 as the elapsed time of movement of the controlled portion of the work machine according to an embodiment of the present invention increases. FIG. 5 is a side view showing the movement of the attachment when the controlled portion of the work machine according to an embodiment of the present invention moves along the corrected target shape. FIG. 6 is a graph showing the time changes in the height of the controlled portion of the work machine according to an embodiment of the present invention and the boom operation command. FIG. 7 is a flowchart of example 1 of the processing by the controller of the control device according to an embodiment of the present invention. FIG. 8 is a flowchart of example 2 of the processing by the controller of the control device according to an embodiment of the present invention.

[0008] An embodiment of the present invention will be described below with reference to the accompanying drawings. Note that the following embodiment is merely an example of a specific embodiment of the present invention and is not intended to limit the technical scope of the present invention. A control device 1 according to this embodiment will be described with reference to FIGS. 1 to 8. FIG. 1 is a side view of a work machine 10 according to this embodiment. FIG. 2 is a block diagram of the control device 1 according to this embodiment. FIG. 3 is a side view showing a corrected target shape and the like when the offset amount approaches zero as the movement distance of the controlled part of the work machine 10 according to this embodiment increases. FIG. 4 is a side view showing a corrected target shape and the like when the offset amount approaches zero as the elapsed time of movement of the controlled part of the work machine 10 according to this embodiment increases. FIG. 5 is a side view showing the movement of the attachment when the controlled part of the work machine 10 according to this embodiment moves along the corrected target shape. FIG. 6 is a graph showing the time changes in the height of the controlled part of the work machine 10 and the boom operation command according to this embodiment. FIG. 7 is a flowchart of Example 1 of processing by the controller 70 of the control device 1 according to this embodiment. FIG. 8 is a flowchart of a second example of processing by the controller 70 of the control device 1 according to this embodiment.

[0009] The control device 1 is a device that controls the movement of the work machine 10 shown in Fig. 1. The control device 1 is equipped with the work machine 10, a detection unit 40 shown in Fig. 2, an input unit 60, a controller 70, and an output unit 80. Note that the control device 1 may not include the work machine 10, or may include a part of it.

[0010] As shown in FIG. 1 , the work machine 10 is a machine that performs work. The work machine 10 may be a construction machine that performs construction work, or a loading and unloading machine that performs loading and unloading work. The work machine 10 may be, for example, a shovel or a crane. The work machine 10 may be a bulldozer or a wheel loader. The following mainly describes the case where the work machine 10 is a shovel. The work machine 10 is configured to be operable by automatic control. The automatic control may be automatic operation or semi-automatic operation (described later). The work machine 10 may also operate in response to operation by a worker (operator) without using automatic control. For example, the work machine 10 may be operated (operated from inside) by a worker in a cab 13c (described later), or may be remotely operated from outside the work machine 10. The work machine 10 includes a machine main body 10a, an attachment 15, a drive control unit 17 (see FIG. 2 ), and an actuator 30.

[0011] The machine body 10a is the main body portion of the work machine 10. The machine body 10a includes a lower body 11 and an upper rotating body 13.

[0012] The lower body 11 rotatably supports the upper rotating body 13. The lower body 11 may be a lower traveling body that can travel on a traveling surface (such as the ground). When the lower body 11 is capable of traveling, the lower body 11 may be provided with crawlers or wheels.

[0013] The upper rotating body 13 is rotatably mounted on the lower main body 11. A boom 15a and the like are attached to the upper rotating body 13. The upper rotating body 13 is equipped with a cab 13c. The cab 13c is a section where a worker (operator) can operate (ride in and operate) the work machine 10.

[0014] (Directions) The direction in which the rotation axis of the upper rotating body 13 extends relative to the lower main body 11 is the up-down direction Z. In the up-down direction Z, the direction from the lower main body 11 toward the upper rotating body 13 is the upward direction Z1, and the direction opposite to the upward direction Z1 is the downward direction Z2. The direction in which the rotation axis of the boom 15a extends relative to the upper rotating body 13 is the lateral direction. The direction perpendicular to both the up-down direction Z and the lateral direction is the fore-and-aft direction X. In the fore-and-aft direction X, the direction in which the attachment 15 protrudes relative to the upper rotating body 13 is the rearward direction X1, and the direction opposite to the rearward direction X1 is the forward direction X2. The up-down direction Z may or may not coincide with the vertical direction, and the fore-and-aft direction X and the lateral direction do not need to coincide with the horizontal direction. Furthermore, when the upper rotating body 13 is rotating relative to the lower main body 11, the above directions are based on the upper rotating body 13.

[0015] The attachment 15 is a part that performs work. The attachment 15 is attached to the machine body 10a. For example, the attachment 15 includes a boom 15a, an arm 15b, a tip attachment 15c, and a control target part 15s (a part that is subject to follow-up control and a part that is subject to stop control).

[0016] The boom 15a is rotatably attached (rotatable along a plane including the front-rear direction X and the up-down direction Z) to the upper rotating body 13. The arm 15b is rotatably attached (rotatable along a plane including the front-rear direction X and the up-down direction Z) to the boom 15a.

[0017] The tip attachment 15c is provided at the tip of the attachment 15. The tip attachment 15c is rotatably mounted on the arm 15b (rotatable along a plane including the front-rear direction X and the up-down direction Z). The tip attachment 15c may be a bucket capable of scooping up and excavating the work object G. The tip attachment 15c may be equipped with a device for gripping the work object G (grapple, nibbler, rotating fork, etc.), a device for crushing the work object G (breaker, etc.), or a magnet for attracting metal work objects G. The work object G (construction object) is the object that the work machine 10 will operate on. The work object G may be soil, granular, chipped, powdered, etc. The work object G may be soil or sand, rock, a magnetic material (such as metal), resin, waste, wood (such as logs), or a structure (such as a block).

[0018] The controlled portion 15s (following control portion, stop control portion) is a specific portion of the attachment 15. For example, the controlled portion 15s is a specific portion of the tip attachment 15c. For example, the controlled portion 15s may be the tip of the tip attachment 15c. The tip of the tip attachment 15c is the end of the tip attachment 15c opposite to the attachment portion (base end) to the arm 15b. The tip of the tip attachment 15c is, for example, the claw of the bucket. The controlled portion 15s may also be a specific portion of the arm 15b (for example, the tip) or a specific portion of the boom 15a.

[0019] This controlled part 15s is the part that is subject to follow-up control (follow-up control target part), which will be described later, and is a part that is controlled to move along the target shape T. The controller 70, which will be described later, controls the attachment 15 in follow-up control so that the controlled part 15s moves along the target shape T.

[0020] This control target part 15s is a part that is the target of stop control (stop control target part) described later, and is a part that is controlled to stop at a target stop position P1 (see FIG. 3). In the stop control, a controller 70 described later controls the attachment 15 so that the control target part 15s stops at the target stop position P1. Note that the follow-up control target part and the stop control target part may be the same part or different parts.

[0021] The drive control unit 17 (see FIG. 2) controls the actuator 30. The drive control unit 17 may include a hydraulic circuit that controls a hydraulic actuator that is operated by hydraulic pressure. The drive control unit 17 may include an electric circuit that controls an electric actuator that is operated by electricity. The drive control unit 17 controls each of the travel motor 31, the swing motor 33, the boom cylinder 35 a, the arm cylinder 35 b, and the tip attachment cylinder 35 c, which will be described later.

[0022] The actuator 30 is a device that moves the work machine 10. The actuator 30 may be a hydraulic actuator that is powered by hydraulic pressure, or an electric actuator that is powered by electricity. The actuator 30 may be equipped with a motor that drives rotation, or may be equipped with a cylinder that drives extension and retraction (telescopic cylinder). The actuator 30 is equipped with a travel motor 31, a swing motor 33, a boom cylinder 35a, an arm cylinder 35b, and a tip attachment cylinder 35c.

[0023] The travel motor 31 generates a driving force for moving the lower body 11. The travel motor 31 may be, for example, a hydraulic motor or an electric motor (the same applies to the swing motor 33). The swing motor 33 generates a driving force for swinging the upper swing body 13 relative to the lower body 11. The boom cylinder 35a extends and retracts to rotate the boom 15a relative to the upper swing body 13. The boom cylinder 35a is, for example, a hydraulic cylinder (the same applies to the arm cylinder 35b and the tip attachment cylinder 35c). The arm cylinder 35b extends and retracts to rotate the arm 15b relative to the boom 15a. The tip attachment cylinder 35c extends and retracts to rotate the tip attachment 15c relative to the arm 15b. If the tip attachment 15c itself is drivable, such as a device for clamping objects, an actuator 30 may be provided for driving the tip attachment 15c. Below, the work machine 10 and the components of the work machine 10 will be described with reference to FIG. 1 (however, for the drive control unit 17, see FIG. 2).

[0024] The detection unit 40 (see Figure 2) detects various conditions. Part or all of the detection unit 40 shown in Figure 2 may be mounted on the work machine 10, or may be located outside the work machine 10. The same applies to the input unit 60, controller 70, and output unit 80, which will be described later, which may be mounted on the work machine 10 or located outside the work machine 10. The detection unit 40 may detect the condition of the work machine 10, or may detect the condition outside the work machine 10 (surrounding conditions). The detection unit 40 includes an attitude detection unit 50.

[0025] The attitude detection unit 50 detects the attitude of the work machine 10. The attitude detection unit 50 may detect the position and orientation of the work machine 10 relative to the work site. The attitude detection unit 50 may detect the position and orientation of a reference position of the work machine 10 relative to the work site. The reference position of the work machine 10 is, for example, a specific position of the upper rotating body 13 or the lower main body 11. The reference position of the work machine 10 may be the attachment portion (boom foot) of the boom 15a to the upper rotating body 13, or a specific position on the rotation center axis of the upper rotating body 13 relative to the lower main body 11. The attitude detection unit 50 may detect the inclination of the work machine 10 with respect to the horizontal plane. The attitude detection unit 50 may detect information (angle, angular velocity, angular acceleration, etc.) about the rotation of the boom 15a relative to the upper rotating body 13. The attitude detection unit 50 may detect information regarding the rotation of the arm 15b relative to the boom 15a. The attitude detection unit 50 may detect information regarding the rotation of the bucket relative to the arm 15b.

[0026] The attitude detection unit 50 may be equipped with one or more types of detection devices. The attitude detection unit 50 may be equipped with a detection device (e.g., a rotary encoder) that detects information about the angle of a certain element of the work machine 10 relative to another element. The attitude detection unit 50 may be equipped with a stroke sensor that detects the stroke of a cylinder (e.g., the boom cylinder 35a) that moves the attachment 15. The attitude detection unit 50 may be equipped with an inclination sensor that detects the angle (inclination) relative to the horizontal direction. The attitude detection unit 50 may be equipped with a sensor (e.g., a gyro sensor) that detects angular velocity relative to the work site, or may be equipped with a sensor that detects acceleration relative to the work site. The attitude detection unit 50 may be equipped with an inertial measurement unit or the like.

[0027] The attitude detection unit 50 may be equipped with a position detection unit that detects the position of a specific part (one or more parts) of the work machine 10 at the work site. In this case, the attitude detection unit 50 may detect the attitude of the "specific part of the work machine 10" based on position information detected by the position detection unit. The attitude detection unit 50 may be equipped with a direction detection unit that detects the direction of the specific part of the work machine 10. The attitude detection unit 50 may be equipped with an imaging device that detects images. The attitude detection unit 50 may detect the attitude of the work machine 10 based on image recognition of a two-dimensional image. The attitude detection unit 50 may detect the attitude of the work machine 10 based on a three-dimensional image (distance image). The attitude detection unit 50 may detect the attitude of the work machine 10 based on a three-dimensional image (distance image) and a two-dimensional image.

[0028] The input unit 60 is used to input information (input device). The input unit 60 is operated by an operator and outputs a signal in accordance with the operation. The input unit 60 outputs information to the controller 70. The input unit 60 may be provided with a touch panel, a mouse, a keyboard, or a switch. The input unit 60 may be provided on a tablet, a smartphone, or a personal computer. The input unit 60 may be provided on the work machine 10, and may be provided in the cab 13c, for example. The input unit 60 may be provided on a remote control device for remotely operating the work machine 10. The input unit 60 may be provided with a switch or the like provided on an operation unit 61 (e.g., an operation lever), or may be provided with a switch or the like provided on a display that displays information about the work machine 10 (e.g., a cluster gauge). The input unit 60 is provided with an operation unit 61.

[0029] The control unit 61 is operated by a worker (operator) who operates the work machine 10. The control unit 61 receives input for operations to move the work machine 10. The control unit 61 may be located in the driver's cab 13c or it may be located in a remote control device for remotely controlling the work machine 10. The control unit 61 may be equipped with a lever (operating lever) or a pedal (operating pedal). The control unit 61 outputs a command corresponding to the operation input to the control unit 61. The control unit 61 may output a command corresponding to the amount of operation input to the control unit 61. The control unit 61 may receive input for operations to move the lower body 11 (traveling operation). The control unit 61 may receive input for operations to rotate the upper slewing body 13 relative to the lower body 11 (slewing operation). The control unit 61 may receive input for operations to move the attachment 15 (attachment operation). The control unit 61 may receive input for an operation to rotate the boom 15a relative to the upper slewing body 13 (boom operation). The control unit 61 may receive input for an operation to rotate the arm 15b relative to the boom 15a (arm operation). The control unit 61 may receive input for an operation to rotate the tip attachment 15c relative to the arm 15b (tip attachment operation).

[0030] The controller 70 is a computer that performs signal input / output, calculations (processing), and information storage. The functions of the controller 70 are realized by the execution of a program stored in the storage unit 70b of the controller 70 by the calculation unit 70a. The controller 70 may be connected to other devices by wireless communication or by wired communication. The components of the controller 70 may be connected to each other by wireless communication or by wired communication. For example, communication is performed by means of communication such as a mobile phone line, optical line, wireless LAN (Local Area Network), or wired LAN. For example, information is input to the controller 70 from the detection unit 40 and the input unit 60. For example, the controller 70 outputs a command (signal) to the drive control unit 17 to move the work machine 10. For example, the controller 70 outputs information to the output unit 80. The controller 70 may be mounted on the work machine 10 or placed outside the work machine 10. The controller 70 may be distributed and placed in multiple locations (constituting a distributed system). The controller 70 includes a calculation unit 70a and a storage unit 70b. Focusing on the functions of the controller 70, the controller 70 includes a work plan setting unit 71 and an automatic control unit 73. The controller 70 will be described below with reference to FIG. 2.

[0031] The arithmetic unit 70a performs calculations (processing) of information. The storage unit 70b stores the information.

[0032] The work plan setting unit 71 sets the work plan for the work machine 10. The work plan is information about the objective of the work of the work machine 10. For example, the work plan includes information about the target shape T (see Figure 3) for the follow control described later. The work plan may also include information about the follow control start position P2 (see Figure 3) described later. The work plan may also include information about the target stop position P1 (see Figure 3) for the stop control described later.

[0033] The automatic control unit 73 automatically controls the movement (including stopping) of the work machine 10. The automatic control unit 73 may control the movement of the work machine 10 in fully automatic operation, or it may control the movement of the work machine 10 in semi-automatic operation. The automatic control unit 73 outputs commands to the drive control unit 17 so that the work machine 10 moves automatically or semi-automatically according to the work plan. The automatic control unit 73 controls the movement of the work machine 10 based on the posture detected by the posture detection unit 50. The automatic control unit 73 performs follow-up control, which will be described later. The automatic control unit 73 may also perform stop control (including deceleration control), which will be described later.

[0034] The output unit 80 is an output device that outputs information. The output unit 80 outputs information based on the signal output from the controller 70. The output unit 80 may output light (such as a display), sound (such as voice), or vibration. The output unit 80 may be provided in a tablet, a smartphone, or a personal computer. The output unit 80 may be provided in the driver's cab 13c. The output unit 80 may be provided in a remote control device for remotely operating the work machine 10. The output unit 80 may be equipped with a display device (monitor).

[0035] (Operation of Work Machine 10) As described above, the work machine 10 shown in FIG. 1 may be operated by an operator in the cab 13c (operated from within), may be remotely operated by an operator from outside the work machine 10 (using a remote control device), or may be automatically operated. The work machine 10 is a machine that utilizes information and communication technology (ICT) (e.g., ICT construction machinery). For example, the work machine 10 may be operated by a machine control system (MC) (semi-automatic operation). Specifically, a work plan (e.g., a target shape T) is set in the controller 70. Then, the operator operates, for example, only some of the elements of the attachment 15 (e.g., only the arm 15b). At this time, the controller 70 automatically controls elements that are not operated by the operator (for example, the boom 15a and the tip attachment 15c) so that the work machine 10 moves in accordance with the work plan (specific examples will be described later). At this time, the controller 70 controls the movement of the work machine 10 based on information detected by the attitude detection unit 50 (the same applies to the case of automatic operation). As a result, the work machine 10 moves in accordance with the work plan.

[0036] Alternatively, for example, the work machine 10 may operate automatically. In this case, the controller 70 controls the movement of the work machine 10 so that it moves automatically according to the work plan.

[0037] (Follow-up control) The controller 70 performs follow-up control. As shown in Figure 3, follow-up control is a control that automatically moves the attachment 15 so that the controlled part 15s (more specifically, the part subject to follow-up control) moves along the target shape T (approaching the target shape T).

[0038] The target shape T is information about the shape of the target movement path (target path) of the control target portion 15s. For example, the target shape T may be a surface (surface information). The target shape T, which is a surface, may be a target construction surface. For example, when the work performed by the work machine 10 using tracking control is excavation work to excavate a work object G (e.g., earth and sand) (hereinafter also referred to as "when excavation work is performed using tracking control"), the target construction surface is the target shape of the surface of the work object G (e.g., the ground) after the work. The target shape T may include one or more planes (flat surfaces). This plane may be a horizontal surface, a vertical surface, or a surface inclined relative to the horizontal direction (an inclined surface). The target shape T may include one or more curved surfaces. The target shape T may be a surface that combines a flat surface and a curved surface. The target shape T may be a line (line information). The target shape T may include one or more straight lines, one or more curved lines, or a line that combines a straight line and a curved line. The target shape T may also include information that includes the positions (coordinates) of multiple target points and information that includes the order of each target point.

[0039] This target shape T may be set by various methods (the same applies to the method of setting information other than the target shape T). For example, information such as the target shape T may be set based on a manual operation (manual input) of the input unit 60 (see FIG. 2) by an operator, or may be information (initial values, initial information) previously set in the controller 70. Information such as the target shape T may also be automatically set by the controller 70 based on some condition (for example, the detection result of the detection unit 40 (see FIG. 2)). Information such as the target shape T may be stored in a storage device external to the controller 70 and set in the controller 70 by being read into the controller 70.

[0040] (Specific Example of Tracking Control) Tracking control may be performed in semi-automatic operation or automatic operation. A specific example of tracking control performed in semi-automatic operation is as follows. Here, an example in which tracking control is performed in semi-automatic operation by arm operation will be described. In this example, an operator performs arm operation on the operation unit 61 (see FIG. 2) to rotate the arm 15b relative to the boom 15a shown in FIG. 1. The arm operation includes an arm pushing operation that moves the tip of the arm 15b in the backward direction X1, and an arm pulling operation that moves the tip of the arm 15b in the forward direction X2. The arm 15b moves in the forward / backward direction X in accordance with the arm operation performed on the operation unit 61 (manual operation). In semi-automatic tracking control, when work is performed to move the tip attachment 15c in the forward / backward direction X, semi-automatic operation is performed by moving the arm 15b in the forward / backward direction X (arm operation), making it easy for the operator to operate intuitively. The operation of the operating unit 61 performed during semi-automatic operation does not have to be arm operation, but may be boom operation or swing operation, for example.

[0041] When an operation (e.g., arm operation) is performed during semi-automatic operation, the controller 70 automatically controls the movement of the boom 15a. Specifically, the controller 70 automatically controls the boom 15a so that the boom 15a rotates in the vertical direction Z relative to the upper rotating body 13. More specifically, the controller 70 calculates the position of the control target portion 15s from the attitude information detected by the attitude detection unit 50 (see FIG. 2). The controller 70 calculates the deviation E of the position of the control target portion 15s from the target shape T shown in FIG. 3. The controller 70 then automatically controls (e.g., proportionally controls) the boom 15a shown in FIG. 1 so that the deviation E approaches zero. This control causes the control target portion 15s to move along the target shape T. For example, when excavation work is performed using tracking control, it is assumed that the tip of the bucket (cutting edge) is set as the control target portion 15s. In this case, the tip of the bucket moves along the target shape T and excavates the work object G using tracking control. As a result, the position and shape of the surface (e.g., the ground) of the work object G become the same or approximately the same as the position and shape of the target shape T (target construction surface).

[0042] In the above example, the controller 70 automatically controls the boom 15 a, but the controller 70 may also automatically control the movement of the tip attachment 15 c. When tracking control is performed in automatic operation, the controller 70 also automatically controls an element (the arm 15 b in the above example) that moves in response to the operation of the operation unit 61 in semi-automatic operation.

[0043] As shown in FIG. 3 , the deviation E is the difference (deviation) in the position of the control target part 15 s relative to the target shape T. In other words, the deviation E is relative position information of the control target part 15 s (the tracking control target part) relative to the target shape T. The deviation E may be a distance deviation E or an angle deviation E (see FIG. 5 ). The distance deviation E is the difference in distance of the control target part 15 s relative to the target shape T in a certain direction (e.g., the tracking cross direction W described below). For example, if the "certain direction" is the vertical direction Z, the distance deviation E is the distance deviation E (height deviation) in the vertical direction Z (height direction). As shown in FIG. 5 , the angle deviation E is defined, for example, as follows: A reference center point O is set. The center point O may be, for example, a position on the target shape T or a specific position on the machine body 10 a (the lower body 11 or the upper revolving body 13) shown in FIG. 1 . As shown in FIG. 5 , the line segment connecting the center point O and the control target part 15 s is designated as line segment L1. An arc having a center at center point O and a radius equal to the length of line segment L is defined as arc C. A line segment connecting the center point O and the intersection point of arc C and target shape T is defined as line segment L2. In FIG. 5, the range of target shape T corresponding to line segment L2 is indicated by symbol L2. In this case, the angle formed by line segments L1 and L2 is defined as angular deviation E. FIG. 5 shows the angular deviation E when target shape T extends in the front-rear direction X and a point on target shape T is defined as center point O.

[0044] (Directions Related to Automatic Control) As shown in FIG. 3 , directions related to automatic control by the controller 70 include a tracking direction U and a tracking cross direction W. The tracking direction U is a direction along the target shape T (more specifically, a pre-correction target shape T1 described later) (the direction in which the target shape T extends). In the tracking direction U, the direction of movement of the control target part 15s during tracking control (the direction of advancement, the direction in which the attachment 15 performs work) is defined as the work progress direction U2. The tracking cross direction W is a direction intersecting (e.g., perpendicular to) the tracking direction U. The tracking cross direction W may be, for example, the direction of the distance deviation E. In the tracking cross direction W, the direction from the control target part 15s before the start of tracking control toward the pre-correction target shape T1 is defined as the approach direction W2, and the direction opposite to the approach direction W2 is defined as the anti-approach direction W1. Note that the tracking direction U and the tracking cross direction W are directions along the plane of movement of the control target part 15s during tracking control.

[0045] In the example shown in FIG. 3 , the direction along the pre-correction target shape T1 is the front-rear direction X, so the following direction U is the front-rear direction X. The following direction U may be the up-down direction Z, the lateral direction, or a direction intersecting these directions. Furthermore, in the example shown in FIG. 3 , the pre-correction target shape T1 is linear. However, if the pre-correction target shape T1 is curved, the following direction U will be a direction along the curved pre-correction target shape T1. In the example shown in FIG. 3 , the work progress side U2 is the near side X2. Which side of the following direction U is the work progress side U2 may be determined depending on the direction of operation of the operation unit 61 (see FIG. 2 ) by the operator, or may be set in advance in the controller 70. In the example shown in FIG. 3 , the following intersecting direction W (the direction of the deviation E) is the up-down direction Z (height direction). In the example shown in FIG. 3 , the approaching side W2 is the lower side Z2, and the anti-approaching side W1 is the upper side Z1. Below, we will mainly explain the case where the following direction U is the forward / backward direction X, the work progress side U2 is the near side X2, the following cross direction W is the up / down direction Z, the approaching side W2 is the lower side Z2, and the anti-approaching side W1 is the upper side Z1.

[0046] (Timing of Start of Follow-Up Control) The timing of start of follow-up control (also referred to as follow-up control start time t2) can be set in various ways. The follow-up control may be started manually or automatically by the controller 70.

[0047] The controller 70 may start the tracking control when an operation to start the tracking control is performed on the input unit 60 (see FIG. 2 ). Specifically, the "operation to start the tracking control" is, for example, an operation to turn on a switch (such as an MC (Machine Control) switch or an MC start switch (an example of the input unit 60)) that commands the start of semi-automatic driving.

[0048] The controller 70 may automatically start the tracking control when a predetermined condition is satisfied. The "predetermined condition" may be, for example, a specific portion of the attachment 15 (e.g., the control target portion 15s) reaching the tracking control start position P2. The tracking control start position P2 (e.g., the MC start position or the MC start height) is set in advance in the controller 70 (before the tracking control is started). The tracking control start position P2 is set at a position different from the target shape T (more specifically, the pre-correction target shape T1). The tracking control start position P2 is set at a position a predetermined distance away from the target shape T on the anti-approach side W1 (e.g., the upper side Z1). This "predetermined distance" is set in advance in the controller 70 (before the tracking control is started). The tracking control start position P2 may be the same position as the target stop position P1 (described in detail below) (details will be described later).

[0049] (Correction of Target Shape T) The controller 70 corrects the target shape T at the start time t2 of the tracking control. The correction of the target shape T is outlined as follows. The controller 70 acquires the deviation Et2 at the start of the tracking control. The controller 70 corrects the target shape T to the position of the control target portion 15s at the start time t2 of the tracking control based on the deviation Et2 at the start of the tracking control. Alternatively, the controller 70 corrects the target shape T to a position between the control target portion 15s and the target shape T at the start time t2 of the tracking control based on the deviation Et2 at the start of the tracking control. The controller 70 corrects the target shape T so that the offset amount To approaches 0 (zero) as the work of the attachment 15 under tracking control progresses. Here, the target shape T before correction is referred to as the pre-correction target shape T1. The target shape T after correction is referred to as the corrected target shape T2. The correction of the target shape T is detailed below.

[0050] (Correction of target shape T at the start of tracking control) The controller 70 acquires the tracking control start deviation Et2. The tracking control start deviation Et2 is the deviation E of the position of the controlled part 15s at t2 at the start of tracking control with respect to the target shape T (specifically, the pre-correction target shape T1).

[0051] The controller 70 corrects the target shape T at the start of tracking control t2. At this time, the controller 70 corrects the target shape T according to the deviation Et2 at the start of tracking control (setting the corrected target shape T2). Specifically, the controller 70 determines the offset amount To according to the deviation Et2 at the start of tracking control. The offset amount To is the difference between the corrected target shape T2 and the target shape T1 before correction (an index indicating the difference in relative position). For example, if the deviation E is a distance deviation E, the offset amount To is also expressed as distance (distance in the direction of the deviation E (tracking crossing direction W)). For example, if the deviation E is an angle deviation E (see Figure 5), the offset amount To is also expressed as an angle. Note that when the deviation E is a distance deviation E, the offset amount To may be expressed as an angle, and when the deviation E is an angle deviation E, the offset amount To may be expressed as distance. Furthermore, the offset described above, i.e., the difference in the relative positions of the pre-correction target shape T1 and the post-correction target shape T2, may be such that parts of the two shapes overlap while other parts differ. Also, the offset amount To may be the maximum value of the difference between the two shapes (an indicator representing the furthest apart parts).

[0052] [Setting Example A1] For example, the controller 70 may correct the target shape T to the position of the controlled part 15s at the start of tracking control t2 (e.g., the MC start coordinate) (set the corrected target shape T2). More specifically, the controller 70 may set the position of the controlled part 15s at the start of tracking control t2 as the position of the controlled part 15s at the start of tracking control t2. In this case, the controller 70 sets the deviation Et2 at the start of tracking control as the offset amount To. The controller 70 sets the position (e.g., height) of the corrected target shape T2 in the tracking intersection direction W as the position (e.g., height) of the controlled part 15s at the start of tracking control t2 in the tracking intersection direction W.

[0053] [Setting Example A2] For example, the controller 70 may correct the target shape T (set the corrected target shape T2) to a position between the position of the control target part 15s at the start time t2 of the tracking control and the target shape T (more specifically, the pre-correction target shape T1). Specifically, the controller 70 may set the position of the corrected target shape T2, which the control target part 15s aims for at the start time t2 of the tracking control, to a position between the position of the control target part 15s at the start time t2 of the tracking control and the pre-correction target shape T1. In this case, the controller 70 sets the offset amount To to be smaller than the deviation Et2 at the start of the tracking control and larger than 0. The controller 70 sets the position (e.g., height) of the corrected target shape T2 in the cross-tracking direction W to be closer to the control target part 15s at the start time t2 of the tracking control (e.g., lower side Z2) and closer to the pre-correction target shape T1 (e.g., upper side Z1).

[0054] (Corrected target shape T2 after start of tracking control (time t3)) The controller 70 corrects the target shape T so that the offset amount To approaches 0 (zero) (so that it gradually decreases) as the work of the attachment 15 progresses under tracking control. The controller 70 sets the offset amount To to 0 when the degree of progress of the work of the attachment 15 reaches a predetermined degree (at time t4). At this time, the controller 70 matches the corrected target shape T2 with the pre-correction target shape T1. The "work progress" of the attachment 15 under tracking control may be the travel distance or the travel time.

[0055] [Setting Example B1] Details of the case where the "work progress" of the attachment 15 under follow-up control is the movement distance of the attachment 15 are as follows: The controller 70 corrects the target shape T so that the offset amount To approaches 0 in accordance with the movement distance (more specifically, the movement distance in the follow-up direction U) of the control target part 15s under follow-up control (from the start time t2 of follow-up control). The controller 70 reduces the offset amount To as the movement distance of the control target part 15s under follow-up control (from the start time t2 of follow-up control) increases.

[0056] [Setting Example B2] The details of the case where the "progress of work" of the attachment 15 in follow-up control is the movement time of the attachment 15 are as follows. As shown in Figure 4, the controller 70 corrects the target shape T so that the offset amount To approaches 0 according to the elapsed time of movement of the controlled part 15s in follow-up control. The "elapsed time of movement of the controlled part 15s in follow-up control" is the total time (cumulative time) that the controlled part 15s has been moving since the start of follow-up control t2. The controller 70 reduces the offset amount To as the elapsed time of movement of the controlled part 15s in follow-up control increases. In this case, the slower the movement speed of the controlled part 15s (for example, a very slow operation), the smaller the distance that the controlled part 15s moves in the follow-up direction U from the start of follow-up control until the offset amount To becomes 0. When the movement speed of the attachment 15 is slow, the offset amount To becomes 0 with only a small movement (immediately) of the controlled part 15s in the tracking direction U. The corrected target shape T2-2 shown in Figure 4 is the corrected target shape T2 when the movement speed of the controlled part 15s is fast, and the corrected target shape T2-1 is the corrected target shape T2 when the movement speed of the controlled part 15s is slow.

[0057] In other words, the controller 70 acquires initial position information (the deviation E), which is the relative position information of the controlled portion 15s with respect to the target shape T at the start of the tracking control. Based on the initial position information, the controller 70 moves one end of the first portion of the target shape T, which is the region close to the controlled portion 15s at the start, to the position of the controlled portion 15s at the start, or to a position between the controlled portion 15s and the target shape T at the start, and corrects the target shape so that the other end of the first portion connects to the second portion, which is the region farther from the controlled portion 15s at the start.

[0058] 3, the controller 70 corrects the portion (first portion) of the target shape T corresponding to the time from the start of tracking control t2 to time t5 so as to move closer to the control target part 15s. As a result, in tracking control, the control target part 15s moves along the corrected first portion and eventually can smoothly reach the original target shape T (second portion).

[0059] 3, the target shape T is corrected so that the first portion is inclined relative to the second portion and approaches the second portion from the one end of the first portion toward the other end of the first portion. As a result, the movement from the first portion to the second portion is smooth. Furthermore, the first portion of the target shape T is corrected so that the first portion has a convex curved surface that faces the target shape T at the start.

[0060] When excavation work is performed using a tracking operation, a finishing operation (see FIG. 1 ) may be performed to finish the work object G (see FIG. 1 ) into a shape that conforms to the target shape T as accurately as possible. Because the accuracy of the position of the attachment 15 is important during finishing work, the movement speed of the attachment 15 is often slowed. When finishing work is performed using semi-automatic operation, the attachment 15 is often operated at a very slow speed. When the "progress of work" refers to the passage of time, slowing down the movement speed of the attachment 15 during finishing work reduces the movement distance of the attachment 15 in the tracking direction U from the start of tracking control until the offset amount To becomes 0. Therefore, during finishing work, the work object G (see FIG. 1 ) can be made closer to a shape that conforms to the pre-correction target shape T1 (the original target shape T) (the work (construction) can be performed as intended).

[0061] [Setting Example C1] As shown in Figure 3, the controller 70 may set the shape of the corrected target shape T2 to be different from the shape of the pre-correction target shape T1. Specifically, the controller 70 sets the position of the corrected target shape T2 that the controlled part 15s targets at the start of the follow control t2 (the start position of the follow control) according to the deviation Et2 at the start of the follow control (as described above). After the start of the follow control (time t3), the controller 70 may set the shape of the corrected target shape T2 such that the offset amount To approaches 0 as the corrected target shape T2 shifts in the follow direction U from the start position of the follow control.

[0062] [Setting Example C2] The controller 70 may set the shape of the corrected target shape T2 to be the same as the shape of the pre-correction target shape T1 (not shown). Specifically, for example, if the pre-correction target shape T1 is a plane (flat surface), the controller 70 may set the corrected target shape T2 to a plane. More specifically, at the start of the tracking control t2, the controller 70 may set the corrected target shape T2 to a position shifted by an offset amount To from the pre-correction target shape T1 without changing its shape. Alternatively, after the start of the tracking control (time t3), the controller 70 may set the shape of the corrected target shape T2 to be the same as the shape of the pre-correction target shape T1, and gradually reduce the offset amount To as the work of the attachment 15 progresses.

[0063] [Setting Example D] The controller 70 may set a corrected target shape T2 on both sides of the tracking direction U (e.g., the rear side X1 and the front side X2) relative to the position of the control target part 15s at the start time t2 of the tracking control. Specifically, for example, the controller 70 may set a corrected target shape T2 for each of a task performed by an arm pulling operation and a task performed by an arm pushing operation. Note that, when the orientation of the work progress side U2 in the tracking control is predetermined (e.g., when it is set in advance in the controller 70), the controller 70 may set the corrected target shape T2 only for the portion of the work progress side U2. Furthermore, when the controller 70 corrects the target shape T so that the offset amount To approaches 0 according to the elapsed time of movement of the control target part 15s in the tracking control (in the case of the above [Setting Example B2]), the corrected target shape T2 is set only for the portion of the work progress side U2.

[0064] (Path Shape of Controlled Part 15s Along Corrected Target Shape T2) The shape of the path (movement path) of the controlled part 15s when the controlled part 15s moves along the corrected target shape T2 is defined as the path shape T2p. Here, the path shape T2p is defined as the (ideal) shape of the path of the controlled part 15s when it is assumed that the controlled part 15s moves exactly along the corrected target shape T2 (see [Example E1 of Path Shape T2p] described later). Note that when the corrected target shape T2 is set as in the above [Setting Example A1] and [Setting Example C1], the path shape T2p is the shape of the corrected target shape T2 itself.

[0065] The path shape T2p may include one or more straight lines. The straight lines may be inclined with respect to the pre-correction target shape T1. The inclination (gradient) of the straight lines with respect to the pre-correction target shape T1 can be set in various ways. The path shape T2p may include one or more curved lines. The curved lines may include an arc shape (e.g., a circular arc shape) or an S-shape. The curved lines may include a curve that smoothly continues (connects) to the pre-correction target shape T1 (without bending). The path shape T2p may be a shape that combines straight lines and curved lines. In the example shown in FIG. 3 , the path shape T2p is a straight line from the position of the control target part 15s at the tracking control start time t2 (strictly speaking, near this position) to a predetermined position, and is a curved line that smoothly continues to the pre-correction target shape T1 on the work progress side U2 of the “predetermined position.”

[0066] (Follow-up control to corrected target shape T2) After correcting the target shape T, the controller 70 automatically moves the attachment 15 so that the control target portion 15s approaches the corrected target shape T2. More specifically, the controller 70 automatically controls (e.g., proportionally controls) the attachment 15 so that the actual deviation E_real approaches 0. The actual deviation E_real is the difference in position of the control target portion 15s relative to the corrected target shape T2. Further details of the follow-up control are as described above in "(Specific example of follow-up control)."

[0067] (Comparison of Correcting and Not Correcting Target Shape T) Specific examples of the operation of the work machine 10 when correcting the target shape T and when not correcting it are as follows.

[0068] Before the start of follow-up control (time t1), the control target part 15s is moved from a position on the anti-approach side W1 (e.g., upper side Z1) of the follow-up control start position P2 to the approach side W2 (e.g., lower side Z2). Before the start of follow-up control (time t1), the work machine 10 may be operated by an operator (operated from inside or remotely), may be operated semi-automatically, or may be operated automatically. In the example shown in FIG. 6, the boom operation command is "lower" from time t1 to the start time t2 of follow-up control. At this time, the boom 15a (see FIG. 1) is lowered (moved to the lower side Z2), and the control target part 15s is lowered. When the controlled part 15s shown in Figure 3 moves to the approaching side W2 (for example, the lower side Z2) and reaches the follow control start position P2 (see Figure 3) (for example, the follow control start height P2z (see Figure 6)) (when follow control starts t2), the controller 70 starts follow control.

[0069] (Example of Problems That Result When Target Shape T Is Not Corrected) A specific example of the operation of the work machine 10 when follow-up control is performed without correcting the target shape T is as follows. In this case, the controller 70 automatically controls the attachment 15 through follow-up control so that the control target portion 15s moves toward the target shape T (toward the approaching side W2). In the example shown in FIG. 6 , even after follow-up control start time t2, the controller 70 sets the boom operation command to "lower" (see the comparative example shown in FIG. 6 ), in the same way as from time t1 to time t2 when follow-up control was started, and controls the boom 15a to be lowered.

[0070] Then, the controlled part 15s reaches the target shape T (the position of the pre-correction target shape T1 in this embodiment). This time is denoted as time t4. At the moment the controlled part 15s reaches the target shape T (at time t4), the controller 70 abruptly changes the movement of the components of the attachment 15 (see Figure 1). For example, the controller 70 abruptly stops the components of the attachment 15. Depending on the conditions, the controller 70 may also move the components of the attachment 15 in opposite directions before and after time t4 (causing a sharp reversal (switching) operation). In the comparative example shown in Figure 6, the controller 70 controls the boom 15a to be lowered before time t4, and controls the boom 15a to be raised after time t4. Thus, in the comparative example shown in Figure 6, the controller 70 attempts to control a sharp reversal operation of the boom 15a at the moment of time t4.

[0071] However, it is difficult for the controller 70 to accurately control sudden changes in the movement (sudden stops, turning operations) of the components of the attachment 15 (e.g., the boom 15a). Examples of the reasons for this are as follows: A delay occurs between when the controller 70 outputs a command to move the actuator 30 shown in FIG. 1 and when the actuator 30 actually moves in accordance with the command (response is affected). Furthermore, fluctuations in the force that the attachment 15 (specifically, the tip attachment 15c) receives from the work object G cause fluctuations in the load on the actuator 30, which in turn causes fluctuations in the command value required to move the actuator 30 (load fluctuations). Furthermore, the inertial force due to the weight of the attachment 15 makes it difficult to move the attachment 15 suddenly. For these reasons, it is difficult for the controller 70 to accurately control sudden changes in the movement of the components of the attachment 15. Therefore, it is difficult to make the controlled part 15s accurately follow the target shape T at the moment it reaches the target shape T (at time t4). Specifically, it is difficult to accurately bring the deviation E (see Figure 3) close to zero. As a result, as shown in the comparative example in Figure 6, the controlled part 15s may move toward the approaching side W2 (for example, the lower side Z2) toward the target shape T, and after reaching the target shape T, it may move beyond the target shape T (for example, move toward the lower side Z2).

[0072] For example, if the target shape T is exceeded when excavation work is performed using tracking control, the attachment 15 shown in FIG. 1 will excavate the work object G beyond the target shape T (over-digging). This will require additional work (additional construction) to replenish the work object G at the over-digged position and perform excavation work again using tracking control along the target shape T. Furthermore, even when work other than excavation work is performed using tracking control, it is not desirable for the control target portion 15s to exceed the target shape T. Therefore, it is important to accurately track the control target portion 15s to the target shape T (to move along the target shape T).

[0073] (When correcting the target shape T) In this embodiment, as shown in Figure 3, the controller 70 corrects the target shape T to the position of the controlled part 15s at the start of follow control t2 (setting the corrected target shape T2) (see [Setting Example A1] above). Alternatively, the controller 70 corrects the target shape T to a position between the controlled part 15s and the target shape T (pre-correction target shape T1) at the start of follow control t2 (setting the corrected target shape T2) (see [Setting Example A2] above). Therefore, the controlled part 15s is more likely to reach the corrected target shape T2 before reaching the pre-correction target shape T1 (original target shape T) (before time t5). Specifically, in the case of [Setting Example A1] above, the controlled part 15s reaches the corrected target shape T2 at the start of follow control t2. Furthermore, in the case of the above [Setting Example A2], the controlled part 15s is likely to reach the corrected target shape T2 before it reaches the pre-correction target shape T1 (early, before time t5).

[0074] Therefore, the controller 70 is likely to perform control to change the movement (stop, reverse) of the components of the attachment 15 (e.g., boom 15a) before the controlled part 15s reaches the pre-correction target shape T1. Thus, when the controlled part 15s reaches the pre-correction target shape T1 (time t5), the need to abruptly change the movement of the components of the attachment 15 (sudden stop, sudden reverse) can be suppressed. As a result, as shown in Figure 6, from the moment the controlled part 15s reaches the pre-correction target shape T1 (time t5), it becomes possible to make the controlled part 15s accurately follow the pre-correction target shape T1 (move along the target shape T). For example, when excavation work is performed with follow control, the attachment 15 shown in Figure 1 is prevented from digging beyond the target shape T into the work object G (over-digging is suppressed).

[0075] In the example shown in Figure 6, when the controlled part 15s reaches the corrected target shape T2 (time t2 when follow-up control starts), the controller 70 starts follow-up control and sets the boom operation command to "raise," controlling it to raise the boom 15a (see Figure 5). The controller 70 then continues to control the boom 15a to raise even after the time t2 when follow-up control starts (without stopping or reversing). In the example shown in Figure 6, the controller 70 also controls the boom 15a to raise when the controlled part 15s reaches the pre-correction target shape T1 (time t5) (without stopping or reversing).

[0076] (Information Output) The controller 70 may cause the output unit 80 (see FIG. 2 (same applies to the output unit 80 below)) to output (for example, display) information relating to the corrected target shape T2.

[0077] (Display of path shape T2p) The controller 70 may display the path shape T2p of the controlled part 15s along the corrected target shape T2 shown in Figure 3 on the output unit 80. In this case, the operator looking at the output unit 80 can grasp the information (position, shape, etc.) of the path shape T2p. As described above, the path shape T2p is the shape of the path of the controlled part 15s when the controlled part 15s moves along the corrected target shape T2.

[0078] [Example E1 of route shape T2p] The route shape T2p displayed by the output unit 80 may be the shape of the route of the control target part 15s when it is assumed that the control target part 15s moves accurately (ideally, with the actual deviation E_real being 0) along the corrected target shape T2.

[0079] [Example E2 of path shape T2p] The path shape T2p displayed by the output unit 80 may be the shape of the path (trajectory) of the controlled part 15s as it actually moved along the corrected target shape T2. For example, as in the above [Setting Example B2], the controller 70 may correct the target shape T so that the offset amount To approaches 0 according to the elapsed time of movement of the controlled part 15s in follow control. In this case, if the movement speed of the controlled part 15s is not predetermined (for example, if it is determined according to manual operation of the operation unit 61), the path of the controlled part 15s cannot be determined until after the controlled part 15s has actually moved. In this case, if the path of the controlled part 15s cannot be determined until after the controlled part 15s has actually moved, the path shape T2p displayed by the output unit 80 will be the shape of the path of the controlled part 15s as it actually moved along the corrected target shape T2.

[0080] The controller 70 may display the pre-correction target shape T1 on the output unit 80. In this case, when the control target part 15s moves along the post-correction target shape T2, the worker looking at the output unit 80 can understand the part of the control target part 15s that does not follow the pre-correction target shape T1.

[0081] (Display of region T2r) The controller 70 displays region T2r on the output unit 80, which is the area between the path shape T2p shown in Figure 5 and the target shape T1 before correction (for example, the area in the following crossing direction W). In this case, the operator looking at the output unit 80 can grasp the information (position, shape, etc.) of region T2r. For example, when excavation work is performed with follow control, this region T2r is the part where the work object G (see Figure 1) cannot be excavated in one operation of the attachment 15 with follow control and remains.

[0082] (Information about the Next Task) As described above, the controller 70 outputs the path shape T2p or the region T2r to the output unit 80. This output allows the worker viewing the output unit 80 to understand the portion of the control target part 15s that did not move along the pre-correction target shape T1 during the current task under tracking control (hereinafter, the "unworkable portion"). As a result, the worker can understand the appropriate start position for the next task under tracking control. This "appropriate start position for the next task under tracking control" is the start position for the next task under tracking control that allows the portion that could not be worked under the current task under tracking control to be worked under the next task under tracking control (the control target part 15s follows the pre-correction target shape T1). For example, assume that the movement direction (the work progress side U2) of the attachment 15 during the current task under tracking control is the forward direction X2. In this case, the controller 70 outputs the path shape T2p or the region T2r to the output unit 80. This output can prompt the operator to start the next follow-up control at an appropriate position on the far side X1 from the start position of the current follow-up control.

[0083] The controller 70 may cause the output unit 80 to output (present) the above-mentioned "appropriate start position for the next tracking control." In particular, the controller 70 may cause the output unit 80 to output a start position for the next tracking control such that the control target portion 15s moves along the pre-correction target shape T1 in the next tracking control in the "portion that could not be worked on" in the work of the current tracking control.

[0084] (Operation of the work machine 10 before follow-up control is started) The following describes the operation of the work machine 10 before follow-up control is performed. Before follow-up control is performed, the work machine 10 may be operated by manual operation by an operator (operation from on board or remote operation), may be operated by semi-automatic operation, or may be operated by automatic operation.

[0085] (Stop Control) The controller 70 may perform stop control before performing follow-up control. The stop control is control that automatically stops the attachment 15 when the control target portion 15s (stop control target portion) shown in FIG. 3 reaches the target stop position P1. The stop control is control that stops the attachment 15 when the attachment 15 is at a position away from the target shape T (on the anti-approach side W1) so that the attachment 15 does not exceed (enter) the target shape T. When excavation work is performed using follow-up control, stopping the control target portion 15s at the target stop position P1 can prevent the attachment 15 (e.g., the control target portion 15s) from exceeding the pre-correction target shape T1 and excavating the work object G (see FIG. 1) (over-digging).

[0086] The target stop position P1 is a target position at which the control target part 15s is stopped. The target stop position P1 is set at a position on the anti-approach side W1 (the side toward the attachment 15 from the pre-correction target shape T1) of the pre-correction target shape T1. The target stop position P1 is set at a position away from the pre-correction target shape T1 on the anti-approach side W1 by a predetermined stop deviation Es. For example, in the example shown in FIG. 3 , the target stop position P1 is set at a position (higher position) on the upper side Z1 by the stop deviation Es from the pre-correction target shape T1.

[0087] The stopping deviation Es is set in advance in the controller 70 (before the stopping control is performed). The stopping deviation Es is set to the following magnitude, for example. Assume that the attachment 15 approaches the target shape T at the maximum anticipated speed while capturing a work object G (see FIG. 1 ) with the largest anticipated mass (for example, a state in which the work object G with the largest anticipated mass is in the bucket). From this state, when the control target portion 15s reaches the target stopping position P1, the attachment 15 is stopped with the maximum operation command. Even in this case, the stopping deviation Es is set so that the control target portion 15s does not exceed the pre-correction target shape T1. For example, the stopping deviation Es may be set based on test results.

[0088] This stop deviation Es may be set (manually) based on operation of the input unit 60 by the operator. The stop deviation Es may also be set automatically by the controller 70 in accordance with certain conditions (conditions for determining the stop deviation Es). The conditions for determining the stop deviation Es may include information detected by the detection unit 40 (see FIG. 2 ), and may include, for example, information about the work machine 10. Specifically, the conditions for determining the stop deviation Es may include information about the movement speed of the attachment 15, or may include information about the mass (own weight) of the attachment 15. The conditions for determining the stop deviation Es may also include the load on the attachment 15. For example, the detection unit 40 may detect the amount (mass, volume, etc.) of the work object G held by the attachment 15 shown in FIG. 1 , and the controller 70 may calculate the load on the attachment 15 from the detected amount of the work object G. Also, for example, the detection unit 40 may detect the magnitude of the load acting on the actuator 30 (e.g., the height of the holding pressure), and the controller 70 may calculate the load acting on the attachment 15 from the magnitude of the detected load.

[0089] 3 may be, for example, a surface (or a target stop surface). In this case, the target stop position P1 may include one or more flat surfaces or one or more curved surfaces (similar to the case where the target shape T is a surface). For example, when the target shape T is a surface, the target stop position P1 may be a surface having the same shape as the target shape T, but shifted by the stop deviation Es to the anti-approach side W1.

[0090] During the stop control, when the controller 70 stops the attachment 15, the controller 70 may terminate the stop control and start the follow-up control. Specifically, when the control target part 15s (more specifically, the stop control target part) is located on the anti-approach side W1 of the target stop position P1, the controller 70 executes the stop control but does not execute the follow-up control. When the control target part 15s (more specifically, the stop control target part) reaches the target stop position P1, the controller 70 stops the attachment 15, terminates the stop control, and starts the follow-up control. In this case, interference (control interference) between the stop control and the follow-up control does not occur.

[0091] For example, the part to be stopped and the part to be followed are the same part (the part to be controlled 15s), and the target stop position P1 and the follow-up control start position P2 are the same position. In this case, the controller 70 switches between stop control and automatic control on the condition that the part to be controlled 15s reaches the follow-up control start position P2, which is the target stop position P1. Note that the target stop position P1 is a different position from the follow-up control start position P2. For example, the target stop position P1 may be a position W1 that is not approaching the follow-up control start position P2.

[0092] (Deceleration Control) The controller 70 may perform deceleration control, limiting the speed of the attachment 15 according to the stopping position deviation F. Deceleration control may be included in the stopping control. The stopping position deviation F is the difference (deviation) of the controlled part 15s (more specifically, the stopping control target part) with respect to the target stopping position P1. The stopping position deviation F may be a difference in distance or a difference in angle, similar to the deviation E described above.

[0093] For example, the controller 70 calculates a restricted operation command (restricted operation command (see Figure 8, described later)) to limit the speed of the attachment 15 according to the stopping position deviation F. This "operation command" is an command to move the attachment 15 (attachment operation command), and is a command that the controller 70 inputs to the drive control unit 17 (see Figure 2). The controller 70 limits the speed of the attachment 15 (increases the degree of restriction) as the controlled part 15s approaches the target stopping position P1. For example, the controller 70 may reduce the maximum value of the attachment speed by decreasing the maximum value of the attachment operation command as the controlled part 15s approaches the target stopping position P1. For example, the controller 70 may control the attachment 15 so that the controlled part 15s gradually decelerates as it approaches the target stopping position P1, and the controlled part 15s stops at the target stopping position P1. For example, the controller 70 may decrease the ratio of the attachment operation command input to the drive control unit 17 to the amount of attachment operation input to the operation unit 61, etc., as the control target part 15s approaches the target stop position P1.

[0094] The elements of the attachment 15 whose speeds are limited by the controller 70 during deceleration control (targets of speed limit during deceleration control) may be some or all of the elements of the attachment 15. For example, the targets of speed limit during deceleration control are elements of the attachment 15 that are moved (operated) when the control target part 15s approaches the target stop position P1. For example, when the control target part 15s is brought closer (lowered) to the target stop position P1 by lowering the boom 15a (see FIG. 1), the boom 15a becomes the target of speed limit during deceleration control. Furthermore, for example, the targets of speed limit during deceleration control may include elements (such as the arm 15b) that are manually operated when tracking control is performed in semi-automatic operation.

[0095] In the example shown in FIG. 8 (see step S213), the controller 70 is previously set with a relationship (e.g., a map) between the deviation E (the difference between the pre-correction target shape T1 shown in FIG. 3 and the control target portion 15s) and the limited operation command. This relationship is set, for example, for each element of the attachment 15 (for each target of speed limit in deceleration control). The limited operation command is an operation command obtained by limiting the original operation command. For example, the limited operation command is an operation command obtained by limiting the operation command corresponding to the operation amount (original operation amount) of the operation unit 61 (see FIG. 2) by the operator. For example, the limited operation command is a maximum value of the operation command corresponding to the deviation E. The controller 70 calculates the limited operation command based on the acquired deviation E and this relationship (map). In the example shown in FIG. 8, the controller 70 does not limit the original operation command when the deviation E is greater than a certain value (predetermined deviation Ea). Furthermore, the controller 70 limits the maximum value of the operation command when the deviation E is equal to or less than the predetermined deviation Ea and equal to or greater than the stop deviation Es. In this case, the controller 70 reduces the limiting operation command (maximum value of the attachment operation command) as the deviation E decreases. In the example shown in FIG. 8 , when the deviation E is equal to or less than the predetermined deviation Ea and equal to or greater than the stop deviation Es, the limiting operation command is a linear function of the deviation E (the graph showing the relationship between the limiting operation command and the deviation E is a straight line). Note that the limiting operation command does not have to be a linear function of the deviation E. The graph showing the relationship between the limiting operation command and the deviation E may be a curved line.

[0096] The controller 70 selects the smaller of the two operation commands: the operation command corresponding to the operation input to the operation unit 61 (see Figure 2) (the original operation command) and the limited operation command determined based on the deviation E (lower selection). The controller 70 determines the lower-selected operation command to be input to the drive control unit 17 as the operation command (the operation command to actually move the attachment 15).

[0097] (Specific Example of Processing by Controller 70) A specific example of processing by the controller 70 will be described with reference to the flowcharts shown in Figures 7 and 8. Unless otherwise specified, the following description will be given in the order of processing performed by the controller 70. Note that the order of processing can be changed in various ways.

[0098] (Processing Example 1) As mentioned above, Figure 7 shows a flowchart of Processing Example 1 of the controller 70. In Processing Example 1, no stop control is performed, and as shown in Figure 3, the corrected target shape T2 is set so that the offset amount To approaches 0 as the movement distance of the controlled part 15s in the follow control increases (see [Setting Example B1] above). In the following, each step shown in Figure 7 will be explained with reference to Figure 7.

[0099] In step S11, the controller 70 sets the pre-correction target shape T1 as shown in Figure 3. As described above, the pre-correction target shape T1 may be set by the operator manually operating the input unit 60 (see Figure 2). The pre-correction target shape T1 may be set in advance in the controller 70, set automatically by the controller 70 according to some conditions, or input to the controller 70 from an external storage device. Specifically, the controller 70 may set information about the shape of the pre-correction target shape T1, set information about the position of the pre-correction target shape T1 (e.g., height), or set information about the inclination angle if the pre-correction target shape T1 is an inclined surface.

[0100] In step S12, the controller 70 acquires the deviation E. Specifically, the controller 70 calculates the position (coordinates) of the control target part 15s from the attitude detected by the attitude detection unit 50 (see FIG. 2). Then, the controller 70 calculates (calculates) the deviation E of the control target part 15s with respect to the pre-correction target shape T1.

[0101] In step S14, the controller 70 determines whether or not to start the tracking control. For example, the controller 70 may determine whether or not an operation to start the tracking control has been input to the input unit 60. Specifically, the controller 70 may determine whether or not the MC switch has been turned on. Furthermore, for example, the controller 70 may determine whether or not the control target part 15s has reached the tracking control start position P2. If the controller 70 determines to start the tracking control, it starts the tracking control and performs the process of step S21. If the controller 70 determines not to start the tracking control, it does not start the tracking control and performs the process of step S15.

[0102] In step S15, the controller 70 manually controls the operation of the attachment 15. In this case, the attachment operation command is an operation command that corresponds to the amount of operation (lever operation amount) of the operation unit 61 (see FIG. 2) by the worker (operator).

[0103] In step S21, the controller 70 corrects the target shape T. Specifically, the controller 70 corrects the target shape T in accordance with the deviation E (deviation Et2 at the start of tracking control) at the start time t2 of tracking control (e.g., the moment the MC switch is turned on). In the example shown in FIG. 7 , the controller 70 corrects the target shape T so that the offset amount To approaches 0 as the moving distance of the control target part 15s in tracking control increases (the above-mentioned [Setting Example B1]).

[0104] In step S22, the controller 70 calculates (calculates) the actual deviation E_real of the control target portion 15s with respect to the corrected target shape T2 shown in FIG. 3 (a specific example of the calculation method is the same as the calculation method for the deviation E).

[0105] In step S23, the controller 70 calculates an attachment operation command (in the figure, "ATT operation command"). The controller 70 calculates the operation command such that the larger the actual deviation E_real, the larger the operation command to move the controlled part 15s closer to the corrected target shape T2 (towards the approach side W2). In this example, the follow control is performed in semi-automatic operation by arm operation. In this case, the controller 70 increases the operation command to move the boom 15a (boom operation command) the larger the actual deviation E_real. Specifically, the controller 70 performs proportional control, making the boom operation command proportional to the actual deviation E_real. In the example shown in Figure 7, the controller 70 uses the product of the proportional control constant (coefficient) Kp and the actual deviation E_real (Kp × E_real) as the boom operation command. When the follow control is performed in semi-automatic operation by arm operation, the controller 70 may also calculate an operation command to move the tip attachment 15c (tip attachment operation command). Furthermore, when follow-up control is performed in semi-automatic operation, the operation command for the operation performed in semi-automatic operation (arm operation in this example) is the operation command corresponding to the amount of operation (lever operation amount) performed by the operator on the control unit 61 (see Figure 2).

[0106] After the processing in step S23 or step S15, the processing flow returns to the start. Note that the process of setting the target shape T (step S11) only needs to be performed once unless the target shape T is changed. The controller 70 continues to calculate the deviation E until tracking control is started (repeat the processing in step S12). After tracking control is started, the controller 70 continues to calculate the actual deviation E_real (repeat the processing in step S22).

[0107] (Processing Example 2) Similarly, Figure 8 shows a flowchart of Processing Example 2 of the controller 70. In Processing Example 2, stop control is performed, and as shown in Figure 4, the corrected target shape T2 is set so that the offset amount To approaches 0 as the elapsed time of movement of the controlled part 15s in the follow control increases (see [Setting Example B2] above). The differences between Processing Example 2 and Processing Example 1 described above will be explained below. In the following, each step shown in Figure 8 will be explained with reference to Figure 8.

[0108] After processing in step S12, the controller 70 performs the processing in step S213. In step S213, the controller 70 performs deceleration control. As described above, the controller 70 calculates a limiting operation command according to the deviation E.

[0109] In step S214, the controller 70 determines whether or not to start follow control. Specifically, the controller 70 determines whether the following conditions are met: the deviation E is less than or equal to the stopping deviation Es, and an operation to start follow control has been input to the input unit 60 (for example, the MC switch is turned on). Note that "deviation E is less than or equal to the stopping deviation Es" means that the controlled part 15s shown in Figure 3 has reached the target stopping position P1. If the controller 70 determines to start follow control, it stops the attachment 15 (performs stop control), finishes the stop process, starts follow control, and performs the process in step S221. If the deviation E is greater than the stopping deviation Es, or if an operation to start follow control has not been input to the input unit 60, the controller 70 determines not to start follow control. If the controller 70 determines not to start follow control, it does not start follow control, performs the process in step S15, and operates the attachment 15 manually.

[0110] In step S221, the controller 70 corrects the target shape T. The controller 70 corrects the target shape T according to the deviation E at the start of the follow control t2 (for example, the moment the MC switch is turned on) (follow control start deviation Et2) (similar to step S21 in processing example 1). In the example shown in Figure 8, the controller 70 corrects the target shape T so that the offset amount To approaches 0 as the elapsed time of movement of the controlled part 15s in the follow control increases. After that, the controller 70 performs the processing in steps S22 and S23 (similar to processing example 1).

[0111] The effects of the control device 1 shown in Fig. 1 are as follows. The control device 1 includes a controller 70 that performs follow-up control. Follow-up control is control that automatically moves the attachment 15 of the work machine 10 so that a specific follow-up control target portion (control target portion 15s) of the attachment 15 moves along the target shape T. The controller 70 acquires the follow-up control start deviation Et2 shown in Fig. 3. The follow-up control start deviation Et2 is the deviation E of the control target portion 15s from the target shape T at the start of follow-up control (follow-up control start time t2).

[0112] [Configuration 1-1] The controller 70 corrects the target shape T to the position of the control target part 15s at the start time t2 of the tracking control based on the deviation Et2 at the start of the tracking control (start time position information). Alternatively, the controller 70 corrects the target shape T to a position between the control target part 15s at the start time t2 of the tracking control and the target shape T based on the deviation Et2 at the start of the tracking control. Note that correcting the target shape T includes changing a part of its shape.

[0113] [Configuration 1-2] As the work of the attachment 15 progresses under tracking control, the controller 70 corrects the target shape T so that the offset amount To approaches 0. The offset amount To is the difference between the target shape T before correction (pre-correction target shape T1) and the target shape T after correction (post-correction target shape T2).

[0114] The above-described [Configuration 1-1] makes it easier for the control target part 15s to reach the post-correction target shape T2 before the control target part 15s reaches the pre-correction target shape T1 (before time t5). Furthermore, the movement of the attachment 15 is likely to change before and after the control target part 15s reaches the post-correction target shape T2. This reduces the need to abruptly change the movement of the attachment 15 at the moment the control target part 15s reaches the pre-correction target shape T1 (at time t5). As a result, for example, the control target part 15s can be prevented from exceeding the pre-correction target shape T1. The above-described [Configuration 1-2] allows the control target part 15s to move along the pre-correction target shape T1 (the original target shape T) as the attachment 15 works under tracking control. Therefore, the attachment 15 can be accurately controlled so that the attachment 15 moves along the target shape T (more specifically, the pre-correction target shape T1).

[0115] For example, when the work performed by the work machine 10 using tracking control is excavation work to excavate a work object G (see FIG. 1) (e.g., earth and sand), the attachment 15 can be prevented from digging too far into the work object G beyond the pre-correction target shape T1. Therefore, the shape of the work object G can be accurately made to follow the pre-correction target shape T1.

[0116] [Configuration 2] The controller 70 corrects the target shape T in accordance with the movement distance of the control target part 15s in the tracking control so that the offset amount To approaches 0 (zero).

[0117] The above-described [Configuration 2] allows the control target part 15s, which moves by tracking control, to gradually approach the pre-correction target shape T1. This further reduces the need to abruptly change the movement of the attachment 15 at the moment when the control target part 15s reaches the pre-correction target shape T1 (at time t5). As a result, the attachment 15 can be controlled with greater precision so that the attachment 15 moves along the target shape T.

[0118] [Configuration 3] The controller 70 corrects the target shape T so that the offset amount To approaches 0 (zero) according to the elapsed time of movement of the controlled part 15s in the follow-up control (see step S221 in Figure 8).

[0119] The above [Configuration 3] provides the following effect. In work where it is important to move the control target part 15s shown in FIG. 4 with precision (such as finishing work), the movement speed of the control target part 15s is slowed. In the above [Configuration 3], the slower the movement speed of the control target part 15s (for example, in very slow operation), the shorter the movement distance of the control target part 15s (more specifically, the movement distance in the following direction U) from the start of following control until the offset amount To becomes 0. Therefore, the control target part 15s can be moved along the pre-correction target shape T1 over a wider range.

[0120] [Configuration 4] The control device 1 includes an output unit 80 (see Figure 2) that outputs information. The controller 70 causes the output unit 80 to display the shape of the path of the controlled part 15s (path shape T2p) when the controlled part 15s moves along the corrected target shape T2 shown in Figure 3.

[0121] With the above configuration [4], the path shape T2p of the controlled portion 15s along the corrected target shape T2 can be understood by the operator by looking at the display on the output unit 80.

[0122] [Configuration 5] The control device 1 includes an output unit 80 (see FIG. 2) that outputs information. The controller 70 causes the output unit 80 to display an area T2r (see FIG. 5) between the path (path shape T2p) of the control target part 15s when the control target part 15s moves along the corrected target shape T2 and the pre-correction target shape T1.

[0123] With the above configuration [5], the area T2r between the path shape T2p and the pre-correction target shape T1 can be made known to the operator by looking at the display of the output unit 80. For example, when excavation work is performed with follow control, if the controlled part 15s moves along the corrected target shape T2, the attachment 15 cannot excavate the work object G (see Figure 1) along the pre-correction target shape T1, resulting in a portion (area T2r) where the work object G remains. In this case, the output unit 80 displays area T2r, allowing the operator who looks at the display of the output unit 80 to know where the work object G remains (area T2r).

[0124] [Configuration 6] The controller 70 sets the target stop position P1 at a position on the side (direction) (anti-approach side W1) from the pre-correction target shape T1 toward the attachment 15, rather than the pre-correction target shape T1. The controller 70 performs stop control. Stop control is a control that automatically stops the attachment 15 when a specific control target part 15s (stop control target part) of the attachment 15 reaches the target stop position P1.

[0125] With the above configuration [6], the controlled part 15s is moved to approach the pre-correction target shape T1, and the attachment 15 stops when the controlled part 15s reaches the target stop position P1. Therefore, it is possible to suppress the controlled part 15s, which is the part to be stopped, from exceeding the pre-correction target shape T1. As a result, it is possible to suppress the controlled part 15s, which is the part to be followed, from exceeding the pre-correction target shape T1. For example, when excavation work is performed with follow-up control, it is possible to further suppress the attachment 15 from digging beyond the pre-correction target shape T1 into the work object G (see Figure 1) (over-digging).

[0126] [Configuration 7] The controller 70 limits the speed of the attachment 15 in accordance with the stop position deviation F, which is the deviation of the controlled part 15s (stop control target part) from the target stop position P1, particularly the closer the relative position of the controlled part 15s is to the target stop position P1.

[0127] According to the above [Configuration 7], the smaller the stop position deviation F, the more the speed of the attachment 15 can be restricted. In this case, the control target part 15s of the attachment 15 can be reliably stopped at the target stop position P1.

[0128] [Configuration 8] When the controller 70 stops the attachment 15 by the stop control, it ends the stop control and starts the follow-up control.

[0129] The above [Configuration 8] makes it possible to prevent control interference between the follow-up control and the stop control.

[0130] (Modifications) The above-described embodiments (including modification examples within the embodiments (the same applies hereinafter)) may be modified in various ways. For example, the number of components in the above-described embodiments may be changed, or some of the components may not be provided. For example, the arrangement of the components may be changed. For example, the connections between the components shown in FIG. 2 and the like may be changed. For example, the inclusion relationships of the components may be modified in various ways. For example, a component described as a lower-level component included in a higher-level component may not be included in this higher-level component, but may be included in another component. For example, what is described as multiple different elements may be combined into a single element. For example, what is described as a single element may be provided as multiple different elements. For example, each component may have only a portion of its features (function, arrangement, shape, operation, etc.).

[0131] For example, the order of steps in the flowcharts shown in Figures 7 and 8 may be changed, some steps may be omitted, and steps from different flowcharts may be combined. For example, various types of information (values, ranges, etc.) (e.g., target shape T) may be pre-set in the controller 70, or they may be set by being read into the controller 70 from an external storage device. Various types of information may be set in the controller 70 based on information set by manual operation by an operator (operation of the input unit 60 (see Figure 2)). Various types of information may be set in the controller 70 based on information detected by the detection unit 40 (see Figure 2). For example, various types of information may not be changed, may be changed by manual operation, or may be automatically changed by the controller 70 according to some condition. For example, the controller 70 may perform substantially the same processing as the processing (calculation, judgment, etc.) of the above embodiment. For example, the mathematical formulas used in the processing, the processing procedures, and the information used in the processing can be changed in various ways. Specifically, the controller 70 may perform processing using information that can be converted into the various types of information used in the above embodiment. The processing performed by the controller 70 may be combined in various ways.

[0132] The control device 1 is configured to perform each of the operations described above. A control program may be set to cause a computer (controller 70) to execute the processes that cause each of the operations described above. A control method may be used to perform each of the operations described above. Each of the operations described above may be referred to as a "step" in the control program and control method described above. For example, the correction of the target shape T may be referred to as a "target shape correction step".

[0133] The above-described specific embodiment includes the invention having the following configuration.

[0134] A control device according to a first aspect of the present invention includes a controller capable of performing tracking control, which is control for automatically moving a specific tracking control target portion of an attachment of a work machine so that the attachment moves along a target shape. The controller acquires start position information, which is position information of the tracking control target portion relative to the target shape at the start of the tracking control, and based on the start position information, moves one end of a first portion, which is an area of ​​the target shape at the start that is close to the tracking control target portion, to a position of the tracking control target portion at the start or to a position between the tracking control target portion and the target shape at the start, and corrects the target shape so that the other end of the first portion is connected to a second portion, which is an area of ​​the target shape at the start that is far from the tracking control target portion.

[0135] In the first embodiment, the controller of the second aspect of the present invention corrects the target shape such that the first portion is inclined with respect to the second portion and approaches the second portion from one end of the first portion toward the other end of the first portion.

[0136] In a third aspect of the present invention, the control device, in the first or second aspect, corrects the target shape such that the smaller the movement speed of the part to be followed in the follow-up control, the smaller the movement distance of the part to be followed in the first part.

[0137] A control device according to a fourth aspect of the present invention includes, in any of the first to third aspects, an output unit that outputs information, wherein the controller causes the output unit to display the shape (trajectory) of the path of the tracking control target part as the tracking control target part moves along the corrected target shape.

[0138] A control device according to a fifth aspect of the present invention is, in any one of the first to third aspects, provided with an output unit that outputs information, and the controller causes the output unit to display the area between the path of the part to be tracked when it moves along the target shape after correction and the target shape before correction.

[0139] A control device according to a sixth aspect of the present invention is any of the first to fifth aspects, in which the controller sets a target stop position at a position that is closer to the target shape before correction in the direction toward the attachment than the target shape before correction, and performs stop control that automatically stops the attachment when a specific stop control target part of the attachment reaches the target stop position.

[0140] A seventh aspect of the present invention provides the control device of the sixth aspect, wherein the controller limits the speed of the attachment more as the relative position of the stop control target portion becomes closer to the target stop position.

[0141] The control device according to an eighth aspect of the present invention is the sixth or seventh aspect, wherein when the attachment is stopped by the stop control, the controller ends the stop control and starts the follow-up control.

[0142] A control device according to a ninth aspect of the present invention, in any of the first to eighth aspects, corrects the first portion of the target shape so that the first portion consists of a convex curved surface toward the target shape at the start.

Claims

1. A control device comprising: a controller capable of performing tracking control, which is control for automatically moving a specific tracking control target portion of an attachment of a work machine so that the attachment moves along a target shape, wherein the controller: acquires start position information, which is position information of the tracking control target portion relative to the target shape at the start of the tracking control; corrects the target shape based on the start position information, to the position of the tracking control target portion at the start, or to a position between the tracking control target portion and the target shape at the start; and corrects the target shape as work by the attachment progresses under the tracking control so that an offset, which is the difference between the target shape before and after correction, approaches zero.

2. A control device according to claim 1, wherein the controller corrects the target shape so that the offset amount approaches zero in accordance with the moving distance of the target part of the tracking control in the tracking control.

3. A control device according to claim 1 or 2, wherein the controller corrects the target shape so that the offset amount approaches zero according to the elapsed time of movement of the target part of the tracking control in the tracking control.

4. A control device according to any one of claims 1 to 3, comprising an output unit that outputs information, wherein the controller causes the output unit to display the shape of the path of the part to be tracked when the part to be tracked moves along the corrected target shape.

5. A control device according to any one of claims 1 to 3, comprising an output unit that outputs information, wherein the controller causes the output unit to display the area between the path of the part to be tracked when it moves along the corrected target shape and the target shape before correction.

6. A control device according to any one of claims 1 to 5, wherein the controller sets a target stop position at a position closer to the target shape before correction in a direction toward the attachment from the target shape before correction, and performs stop control that automatically stops the attachment when a specific portion of the attachment that is subject to stop control reaches the target stop position.

7. A control device according to claim 6, wherein the controller limits the speed of the attachment as the relative position of the stop control target portion becomes closer to the target stop position.

8. A control device according to claim 6 or 7, wherein when the attachment is stopped by the stop control, the controller ends the stop control and starts the follow-up control.

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