JP2024111513A - Automatic control system of work machine and control method of work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic control system of a work machine and a control method of the work machine capable of suppressing interference between a work tool and an object to be loaded.

SOLUTION: A posture detection sensor 20 detects a posture of a work machine 2. A controller 50 identifies a soil discharge point P2 and a passing point P1A on a passage through which a bucket 8 passes upon rotation of a rotational structure 3 based on a detection result of the posture detection sensor 20, sets a position shifted to an opposite side of the soil discharge point P2 from the passing point P1A as a corrected passing point P1B, and controls the bucket 8 to pass through the corrected passing point P1B upon rotation.

SELECTED DRAWING: Figure 5

COPYRIGHT: (C)2024,JPO&INPIT

Description

This disclosure relates to an automatic control system for a work machine and a control method for a work machine.

JP 2019-190234 A (Patent Document 1) describes a technology for changing the target rotation speed during rotation of a rotating body during automatic loading so that the bucket does not interfere with the loading target.

JP 2019-190234 A

However, in the technology described in Patent Document 1, depending on the movement trajectory of a work machine having a tool such as a bucket, there is a possibility that the tool may come into contact with the loading target.

The objective of this disclosure is to provide an automatic control system for a work machine and a control method for a work machine that can reduce interference between a work tool and a loading target.

The automatic control system for a work machine disclosed herein includes a rotating body, a working implement, a posture detection sensor, and a controller. The rotating body rotates. The working implement is attached to the rotating body and has a working implement. The posture detection sensor detects the posture of the working implement. The controller identifies a dumping point and a passing point on the path that the working implement passes through when the rotating body rotates based on the detection result of the posture detection sensor, sets a position shifted from the passing point to the opposite side of the dumping point as a corrected passing point, and controls the working implement to pass through the corrected passing point when rotating.

The control method for a work machine disclosed herein is a control method for a work machine that has a rotating body and a work implement that is attached to the rotating body and has a working tool, and includes the following steps.

Based on the detection results of the work implement's posture, a dumping point and a passing point are identified on the path that the work implement passes through when the rotating body rotates. A position shifted from the passing point to the opposite side of the dumping point is set as the corrected passing point. The work implement is controlled to pass through the corrected passing point when rotating.

This disclosure makes it possible to realize an automatic control system for a work machine and a control method for a work machine that can reduce interference between a work tool and a loading target.

1 is a diagram showing a configuration of a hydraulic excavator as an example of a work machine in an embodiment of the present disclosure. FIG. FIG. 1 is a diagram showing an operation flow of excavation and loading by a hydraulic excavator. FIG. 2 is a perspective view showing a state in which a hydraulic excavator performs automatic loading. FIG. 13 is a diagram showing a movement trajectory of a bucket during automatic loading control. FIG. 2 is a block diagram showing an automatic control system for the hydraulic excavator of FIG. 1 . FIG. 4 is a flowchart showing a control method for a hydraulic excavator in one embodiment of the present disclosure.

The following describes an embodiment of the present disclosure with reference to the drawings.

In the specification and drawings, identical or corresponding components are given the same reference numerals and redundant explanations will not be repeated. In addition, in the drawings, configurations may be omitted or simplified for the convenience of explanation.

In the following description, "up," "down," "front," "rear," "left," and "right" refer to directions relative to the operator seated in the driver's seat 4S in the driver's cab 4 shown in Figure 1.

<Configuration of the work machine>
The configuration of a hydraulic excavator as an example of a work machine according to the present disclosure will be described with reference to FIG. 1 .

Figure 1 is a diagram showing a schematic configuration of a hydraulic excavator according to one embodiment of the present disclosure. As shown in Figure 1, the hydraulic excavator 100 of this embodiment has a main body 1 and a hydraulically operated work machine 2. The main body 1 has a rotating body 3 and a traveling body 5.

The running body 5 has a pair of tracks 5Cr and a travel motor 5M. The hydraulic excavator 100 can travel by rotating the tracks 5Cr. The travel motor 5M is provided as a drive source for the running body 5. The travel motor 5M is a hydraulic motor that is operated by hydraulic pressure. The running body 5 may have wheels (tires).

The rotating body 3 is placed on the running body 5 and is supported by the running body 5. The rotating body 3 can be rotated relative to the running body 5 around a rotation axis RX by a rotation motor (not shown). The rotation motor is a hydraulic motor that operates by hydraulic pressure. The rotation axis RX is a virtual straight line that is the center of rotation of the rotating body 3. The traveling motor 5M or the rotation motor may be an electric motor.

The rotating body 3 has a cab 4. A driver's seat 4S is provided in the cab 4 where an operator sits. The operator (crew) sits in the cab 4 and can operate the work equipment 2, rotate the rotating body 3 relative to the travelling body 5, and operate the hydraulic excavator 100 using the travelling body 5. The rotating body 3 has an exterior cover 9. The exterior cover 9 covers the machine room. The hydraulic excavator 100 may be remotely operated.

The work machine 2 is supported by the rotating body 3. The work machine 2 has a boom 6, an arm 7, and a bucket 8. The work machine 2 further has a boom cylinder 10, an arm cylinder 11, and a bucket cylinder 12.

The boom 6 is rotatably connected to the main body 1. Specifically, the base end of the boom 6 is rotatably connected to the rotating body 3 with the boom foot pin 13 as a fulcrum. The arm 7 is rotatably connected to the boom 6. Specifically, the base end of the arm 7 is rotatably connected to the tip of the boom 6 with the boom top pin 14 as a fulcrum. The bucket 8 is rotatably connected to the arm 7. Specifically, the base end of the bucket 8 is rotatably connected to the tip of the arm 7 with the arm top pin 15 as a fulcrum. The bucket 8 may be another working tool such as a grapple. Since the total length of the grapple varies depending on whether the claws are open or closed, there is a risk that the grapple may interfere with the loading target 200 due to a change in the state or posture of the grapple. The present disclosure can be applied to any working tool whose horizontal length varies depending on the state or posture, or any working machine whose relative positional relationship with the loading target 200 changes.

One end of the boom cylinder 10 is connected to the rotating body 3, and the other end is connected to the boom 6. The boom 6 can be driven relative to the main body 1 by the boom cylinder 10. This drive allows the boom 6 to rotate vertically relative to the rotating body 3, with the boom foot pin 13 as a fulcrum.

One end of the arm cylinder 11 is connected to the boom 6, and the other end is connected to the arm 7. The arm 7 can be driven relative to the boom 6 by the arm cylinder 11. This drive allows the arm 7 to rotate up and down or back and forth relative to the boom 6, with the boom top pin 14 as a fulcrum.

One end of the bucket cylinder 12 is connected to the arm 7, and the other end is connected to the bucket link 17. The bucket 8 can be driven relative to the arm 7 by the bucket cylinder 12. This drive allows the bucket 8 to rotate up and down or forward and backward relative to the arm 7, with the arm top pin 15 as a fulcrum.

Each of the boom cylinder 10, arm cylinder 11 and bucket cylinder 12 is a hydraulic cylinder driven by hydraulic pressure, but may also be other actuators such as electric cylinders.

The hydraulic excavator 100 further includes a work machine attitude sensor 20 (FIG. 5), a position and orientation sensor 21, an inclination sensor 22 (FIG. 5), and a detection sensor 23. The work machine attitude sensor 20 detects the attitude of the work machine 2 and outputs an attitude signal indicating the attitude of the work machine 2. The work machine attitude sensor 20 can detect the attitude of each of the boom 6, the arm 7, and the bucket 8. The work machine attitude sensor 20 includes sensors disposed on each of the boom 6, the arm 7, and the bucket 8. The work machine attitude sensor 20 may be any one of an IMU (Inertial Measurement Unit), a stroke sensor, a potentiometer, an imaging device, and the like, or any combination of these.

The position and orientation sensor 21 is, for example, a GNSS (Global Navigation Satellite Systems) receiver. The position and orientation sensor 21 includes two GNSS receivers 21a, 21b. Each of the two GNSS receivers 21a, 21b is installed at a different position on the rotating unit 3. Each of the GNSS receivers 21a, 21b receives a satellite positioning signal from a satellite indicating the position of the rotating unit 3 in the global coordinate system. The position and orientation sensor 21 outputs the received satellite positioning signal indicating the position of the rotating unit 3 in the global coordinate system. The controller 50 calculates the position of the rotating unit 3 in the global coordinate system and the direction in which the rotating unit 3 is facing from this satellite positioning signal.

The position and orientation sensor 21 may have a rotation angle sensor. The rotation angle sensor is fixed to the rotating body 3, for example. The rotation angle sensor detects the rotation angle of the rotating body 3 relative to the running body 5, and outputs a rotation angle signal indicating the rotation angle of the rotating body 3. The rotation angle sensor can detect the rotation angle in the machine coordinate system (local coordinate system). The rotation angle sensor may be an IMU, a potentiometer, an imaging device, or any combination of these. The machine coordinate system is an orthogonal coordinate system whose origin is the center of rotation of the rotating body 3 and is represented by an axis extending in the front-rear direction, an axis extending in the left-right direction, and an axis extending in the up-down direction (rotation axis RX).

The tilt sensor 22 measures the acceleration and angular velocity (rotation speed) of the rotating body 3, and detects the attitude of the rotating body 3 (e.g., roll angle, pitch angle, yaw angle) based on the measurement results. The tilt sensor 22 is installed, for example, on the underside of the rotating body 3. The tilt sensor 22 is, for example, an IMU. The tilt sensor 22 outputs a tilt signal obtained by the measurement.

The detection sensor 23 detects the terrain or objects around the work site of the hydraulic excavator 100. The detection sensor 23 may be attached to, for example, the operator's cab 4, the exterior cover 9, or a location other than these. The detection sensor 23 outputs a detection signal based on the detected information.

The detection sensor 23 is, for example, a LiDAR (Light Detection and Ranging) that emits laser light to acquire information about the target. The detection sensor 23 may also be a Radar (Radio Detection and Ranging) that acquires information about the target by emitting radio waves. The radar may be, for example, a millimeter wave radar that uses a receiving antenna to detect how millimeter wave band radio waves emitted from a transmitting antenna are reflected off the surface of an object and returned. The detection sensor 23 may also be a visual sensor including a camera. The detection sensor 23 may also have a function of detecting the attitude of the work machine 2, similar to the work machine attitude sensor 20.

The hydraulic excavator 100 further has a command unit 24 (Fig. 5) and an operation unit 25 (Fig. 5). The command unit 24 and the operation unit 25 are each disposed in the cab 4. The command unit 24 and the operation unit 25 are manually operated by an operator in the cab 4, and output operation commands for manual operation. The command unit 24 is a section for indicating the point through which the bucket 8 should pass in automatic loading control. The operation unit 25 is a section for controlling the movement, rotation, and traveling of the boom 6, arm 7, and bucket 8.

<Excavation and loading operation flow and automatic loading control>
Next, the operation flow of excavation and loading by the work machine and the automatic loading control will be described with reference to Figs.

Figure 2 shows the operational flow of excavation and loading by a hydraulic excavator. Figure 3 is a perspective view showing how the hydraulic excavator performs automatic loading. Figure 4 shows the movement trajectory of the bucket during automatic loading control.

As shown in Figures 2 and 3, in excavation and loading by the hydraulic excavator 100, excavation is first performed (step SA). This excavation loads a load such as soil into the bucket 8. After excavation, the rotating body 3 rotates with the load loaded into the bucket 8 (step SB). This rotation is the so-called loading rotation. During this loading rotation, the bucket 8 is controlled so as not to interfere with the object 200 to be loaded. The object 200 to be loaded is, for example, a dump truck. The dump truck 200 has a vessel 200A for loading the load in the bucket 8.

When the bucket 8 reaches the point where the load in the bucket 8 is dumped into the vessel 200A by the loading rotation, the rotation of the rotating body 3 stops. After this, the load in the bucket 8 is discharged (discharged) into the vessel 200A of the dump truck 200 (step SC). After the discharge, the rotating body 3 rotates back to excavate again (step SD).

As shown in FIG. 3, in order to automate the above loading operation, it is necessary to identify the points through which the bucket 8 passes during the loading operation. In automation, it is necessary to control the operation of the work machine 2 so that the bucket 8, which is a work tool, does not interfere with the vessel 200A. At least a passing point (interference avoidance point) P1A, a discharge point P2, and a return point (digging point) P3 are identified as points through which the bucket 8 must pass during the loading operation.

Passing point P1A is a point where the center of the arm top pin 15 in the left-right direction is located directly above the side edge SE of the loading object 200 (for example, the side edge of the vessel 200A). Discharge point P2 is a point where the center of the arm top pin 15 in the left-right direction is located directly above the loading object 200 (for example, the vessel 200A). Return point P3 is a point where the center of the arm top pin 15 in the left-right direction is located directly above the location where excavation is performed. Here, in order to identify passing point P1A, discharge point P2, and return point P3, the point where the center of the arm top pin 15 in the left-right direction is located is described, but other points may be used to identify them. For example, passing point P1A, discharge point P2, and return point P3 may be identified using a point on the blade tip 8T of the bucket 8. In addition, for example, the position of the loading target 200 may be detected by an external sensor, and when the indicator 24 is operated, the passing point P1A, the unloading point P2, and the return point P3 may be identified using the point on the working machine 2 that is closest relative to the loading target 200.

The passing point P1A, the unloading point P2, and the return point P3 are each identified by, for example, the operator operating the indicator 24 while the rotating body 3 is rotating. Specifically, the operator operates the indicator 24 when he visually determines that the center of the arm top pin 15 in the left-right direction is located directly above the side edge SE of the loading target 200 (for example, the side edge of the vessel 200A) during the rotation of the rotating body 3. The operator also operates the indicator 24 when he visually determines that the center of the arm top pin 15 in the left-right direction is located directly above the point where the load in the bucket 8 should be unloaded during the rotation of the rotating body 3. The operator also operates the indicator 24 when he visually determines that the center of the arm top pin 15 in the left-right direction is located directly above the point where excavation should be performed during the rotation of the rotating body 3.

The coordinates of each of points P1A, P2, and P3 in the machine coordinate system are calculated based on the posture of the work machine 2 and the rotation angle of the rotating body 3 at the time the operator operates the instruction unit 24. This identifies each of points P1A, P2, and P3. Points P1A, P2, and P3 are identified, for example, during return rotation after unloading. In automatic loading control, the operation of the work machine 2 and the rotation of the rotating body 3 are controlled so that the left-right center of the arm top pin 15 passes through the passing point P1A from the return point P3 to the unloading point P2.

The passing point P1A is specified so that the bucket 8 does not interfere with the loading target 200. However, depending on the movement trajectory of the bucket 8, the bucket 8 may interfere with the loading target 200. Specifically, as shown in FIG. 4, in the automatic loading control, the center of the arm top pin 15 in the left-right direction moves from the return point P3 to the passing point P1A and reaches the unloading point P2 as described above. At this time, the movement trajectory from the return point P3 to the passing point P1A is not specified. Or, even if the movement trajectory from the return point P3 to the passing point P1A is specified, there may be a variation in control. For this reason, there are cases where the passing point P1A is reached from the return point P3 via the movement trajectory R1, and cases where the passing point P1A is reached from the return point P3 via the movement trajectory R2. For example, when the weight of the load loaded into the bucket 8 is large, there is a high tendency for the movement trajectory R2 to be more likely than the movement trajectory R1. If the bucket 8 moves along the movement trajectory R2 in this manner, there is a risk that the bucket 8 will interfere with the loading target 200 (vessel 200A).

Therefore, in this disclosure, during automatic loading control, the passing point P1A is calibrated to a corrected passing point P1B so that the bucket 8 does not interfere with the loading target 200 regardless of the movement trajectory from the return point P3 to the passing point. An automatic control system for a work machine and a control method for a work machine that calibrates the passing point P1A to the corrected passing point P1B are described below.

<Automatic control system for work machines>
First, the configuration of the automatic control system in this embodiment will be described with reference to FIG.

FIG. 5 is a block diagram showing an automatic control system for a hydraulic excavator according to the present disclosure. As shown in FIG. 5, the automatic control system has a controller 50. The controller 50 includes a processor, a main memory, and a storage unit 53. The processor is, for example, a CPU (Central Processing Unit). The main memory includes, for example, a non-volatile memory such as a ROM (Read Only Memory) and a volatile memory such as a RAM (Random Access Memory). The controller 50 reads out a program stored in the storage unit 53, expands it in the main memory, and executes a predetermined process according to the program.

The controller 50 has an indication point identification unit 51, a corrected passing point calculation unit 52, a memory unit 53, and an EPC valve control unit 54.

The indication point identification unit 51 acquires the attitude signal output from the work machine attitude sensor 20. The indication point identification unit 51 acquires the satellite positioning signal and the turning angle signal output from the position and orientation sensor 21. The indication point identification unit 51 acquires the tilt signal output from the tilt sensor 22. The indication point identification unit 51 acquires the detection signal output from the detection sensor 23. The indication point identification unit 51 acquires the indication signal output from the indication unit 24.

The indication point identification unit 51 identifies the coordinates of the point through which the bucket should pass during automatic loading control. Specifically, the indication point identification unit 51 calculates the coordinates of the center position in the left-right direction of the arm top pin 15 at the time when the indication signal is received from the indication unit 24.

When the operator operates the instruction unit 24 to obtain the passing point P1A, the coordinates of the center position in the left-right direction of the arm top pin 15 at the time when the instruction unit 24 is operated are calculated by the passing point identification unit 51A as the coordinates of the passing point P1A. Also, when the operator operates the instruction unit 24 to obtain the earth discharge point P2, the coordinates of the center position in the left-right direction of the arm top pin 15 at the time when the instruction unit 24 is operated are calculated by the earth discharge point identification unit 51B as the coordinates of the earth discharge point P2. Also, when the operator operates the instruction unit 24 to obtain the return point P3, the coordinates of the center position in the left-right direction of the arm top pin 15 at the time when the instruction unit 24 is operated are calculated by the return point identification unit 51C as the coordinates of the return point P3.

The coordinates of each of points P1A, P2, and P3 are calculated based on signals acquired from each of the work machine attitude sensor 20, the position and orientation sensor 21, and the tilt sensor 22. At this time, the indication point identification unit 51 may refer to the dimensions of each component of the work machine 2 stored in the memory unit 53. The indication point identification unit 51 outputs the coordinate signals of the identified passing point P1A, earth discharge point P2, and return point P3 to the corrected passing point calculation unit 52.

In the figure, the passing point identification unit 51A, the earth discharge point identification unit 51B, and the return point identification unit 51C are shown separately, but the passing point identification unit 51A, the earth discharge point identification unit 51B, and the return point identification unit 51C may not be separate and may be the same part. In other words, each point P1A, P2, and P3 may be identified by the same part of the indication point identification unit 51. Furthermore, the indication point identification unit 51 may output the coordinate signals of the identified earth discharge point P2 and return point P3 directly to the EPC valve control unit 54, rather than to the corrected passing point calculation unit 52.

The modified pass point calculation unit 52 acquires the coordinate signal of the pass point P1A from the pass point identification unit 51A. The modified pass point calculation unit 52 calibrates the acquired coordinate of the pass point P1A to the modified pass point P1B.

As shown in FIG. 4, the coordinates of the passing point P1A are calibrated by setting a position shifted by a distance L from the passing point P1A on the opposite side of the unloading point P2 as a corrected passing point P1B, and calculating the coordinates of the corrected passing point P1B.

The distance L by which the position is shifted is, for example, equal to or greater than half (W/2) of the width W (FIG. 1) of the bucket 8 in the left-right direction. This further prevents the bucket 8 from interfering with the loading target 200.

Moreover, the corrected passing point P1B is set at a position shifted from the passing point P1A in the horizontal direction in a machine coordinate system (local coordinate system) based on the hydraulic excavator 100. Specifically, when the hydraulic excavator 100 is placed on a horizontal plane in the global coordinate system, the horizontal direction in the global coordinate system and the horizontal direction in the machine coordinate system coincide. Therefore, in this case, the corrected passing point P1B is set at a position shifted from the passing point P1A in the horizontal direction of the machine coordinate system, which is the same as the horizontal direction of the global coordinate system.

On the other hand, when the hydraulic excavator 100 is placed on a slope that is inclined with respect to the horizontal plane in the global coordinate system, the horizontal direction in the global coordinate system does not coincide with the horizontal direction in the machine coordinate system. For this reason, in this case, the corrected passing point P1B is set at a position shifted by a distance L from the passing point P1A, for example, on the opposite side of the earth discharge point P2, in the horizontal direction of the machine coordinate system, which is different from the horizontal direction of the global coordinate system.

As shown in FIG. 5, when calculating the corrected passing point P1B, the corrected passing point calculation unit 52 refers to shape data of the bucket 8 stored in the memory unit 53. The memory unit 53 stores dimensions of each component of the work machine 2, etc.

Various information is input to the memory unit 53 from the input device 26. The input device 26 may be a touch panel, a keyboard, or the like. The input device 26 may be mounted on the hydraulic excavator 100, or may be located away from the hydraulic excavator 100 and connected to the controller 50 by wire or wirelessly. The memory unit 53 may also store shape data of the bucket 8 (work tool) and the like in advance, and this data may be transmitted wirelessly from the outside to the memory unit 53 by the input device 26.

The corrected passing point calculation unit 52 outputs signals indicating the coordinates of the calculated corrected passing point P1B, the discharge point P2, and the return point P3 to the EPC valve control unit 54. The EPC valve control unit 54 controls the EPC valve 28 based on the signals indicating the coordinates of the acquired corrected passing point P1B, the discharge point P2, and the return point P3.

The EPC valve 28 controls the hydraulic valve 30 based on a command current from the EPC valve control section 54 of the controller 50. In this way, the EPC valve 28 controls the supply of oil pumped up from an oil tank (not shown) by the hydraulic pump 27 to the actuator 29. The actuator 29 is, for example, a hydraulic actuator, such as the boom cylinder 10, the arm cylinder 11, the bucket cylinder 12, or a swing motor.

By controlling the EPC valve 28 by the EPC valve control unit 54, each hydraulic actuator is controlled so that the center of the arm top pin 15 in the left-right direction passes from the return point P3 through the corrected passing point P1B and reaches the unloading point P2 during automatic loading control. This enables automatic loading control in which interference between the bucket 8 and the loading target 200 is suppressed.

The EPC valve control unit 54 acquires an operation signal from the operation unit 25. The EPC valve control unit 54 may control the EPC valve 28 based on a manual operation command output from the operation unit 25. This allows the operator to manually operate the operation of the work machine 2 and the rotation of the rotating body 3. This allows the operator to move the work machine to the positions that serve as the passing point P1A, the earth discharge point P2, and the return point P3.

The series of excavation and loading operations shown in FIG. 2 may also be fully automated based on the detection signal from the detection sensor 23. The detection sensor 23 detects the situation and objects around the hydraulic excavator 100, making it possible to detect the relative positional relationship between the hydraulic excavator 100 and the excavation point or loading target 200. This makes it possible to automatically identify the passing point P1A, the earth discharge point P2, and the return point P3 during automatic return swing SD (FIG. 2). Furthermore, the detection sensor 23 detects the topography and other factors around the hydraulic excavator 100, making it possible to automatically perform excavation SA (FIG. 2). This makes it possible to fully automate the series of excavation and loading operations in combination with automatic loading control.

The controller 50, the instruction unit 24, the operation unit 25, and the input device 26 may each be mounted on the hydraulic excavator 100, or may be disposed remotely outside the hydraulic excavator 100. When the controller 50, the instruction unit 24, the operation unit 25, and the input device 26 are disposed remotely outside the hydraulic excavator 100, the controller 50, the instruction unit 24, the operation unit 25, and the input device 26 may each be wirelessly connected to the various sensors 20 to 23, the EPC valve 28, and the like. The controller 50 may be stored in a server separate from the hydraulic excavator 100. In addition, since the operation unit 25 is separate from the hydraulic excavator 100, the operator may operate the hydraulic excavator 100 remotely without being seated in the driver's seat 4 of the hydraulic excavator 100.

<Method of controlling a work machine>
Next, a control method for the work machine in this embodiment will be described with reference to FIGS.

Figure 6 is a flow diagram showing a control method for a hydraulic excavator in one embodiment of the present disclosure. As shown in Figures 5 and 6, the indication point identification unit 51 of the controller 50 acquires the attitude signal (working machine attitude information) output from the working machine attitude sensor 20 (step S1: Figure 6). The indication point identification unit 51 of the controller 50 acquires the satellite positioning signal and the turning angle signal (turning angle information) output from the position and orientation sensor 21 (step S2: Figure 6). The indication point identification unit 51 of the controller 50 acquires the tilt signal output from the tilt sensor 22. The indication point identification unit 51 of the controller 50 acquires the detection signal output from the detection sensor 23. The indication point identification unit 51 of the controller 50 acquires the indication signal output from the indication unit 24.

The indication point identification unit 51 of the controller 50 identifies the coordinates of the point through which the bucket 8 should pass during automatic loading control. Specifically, the indication point identification unit 51 calculates the coordinates of the center position in the left-right direction of the arm top pin 15 at the time when the indication signal is received from the indication unit 24.

When the operator determines that the left-right center of the arm top pin 15 is located directly above the side edge of the loading target 200 and operates the indicator 24, or when the detection sensor 23 determines this, the coordinates of the left-right center position of the arm top pin 15 at that timing are calculated by the pass point identification unit 51A as the coordinates of pass point P1A. This identifies pass point P1A (step S3: Figure 6).

In addition, when the operator determines that the left-right center of the arm top pin 15 is located directly above the point where the load is to be discharged and operates the instruction unit 24, or when the detection sensor 23 determines this, the coordinates of the left-right center position of the arm top pin 15 at that timing are calculated by the discharge point identification unit 51B as the coordinates of the discharge point P2. This identifies the discharge point P2.

In addition, when the operator determines that the left-right center of the arm top pin 15 is located directly above the point to be excavated and operates the indicator 24, or when the detection sensor 23 determines this, the coordinates of the left-right center position of the arm top pin 15 at that timing are calculated by the return point identification unit 51C as the coordinates of the return point P3. This identifies the return point P3.

The instruction point identification unit 51 outputs the coordinate signals of the identified passing point P1A, earth discharge point P2, and return point P3 to the modified passing point calculation unit 52. Note that the instruction point identification unit 51 may output the coordinate signals of the identified earth discharge point P2 and return point P3 directly to the EPC valve control unit 54, instead of to the modified passing point calculation unit 52.

When the modified pass point calculation unit 52 acquires the coordinate signal of the pass point P1A from the pass point identification unit 51A, it calibrates the acquired coordinate of the pass point P1A to the modified pass point P1B. That is, the modified pass point calculation unit 52 of the controller 50 calculates the modified pass point P1B by modifying the pass point P1A (step S4: FIG. 6).

As explained with reference to FIG. 4, the coordinates of the passing point P1A are calibrated by setting a position shifted by a distance L from the passing point P1A on the opposite side of the unloading point P2 as the corrected passing point P1B, and then calculating the coordinates of the corrected passing point P1B.

The corrected passing point calculation unit 52 outputs signals indicating the coordinates of the calculated corrected passing point P1B, the discharge point P2, and the return point P3 to the EPC valve control unit 54. The EPC valve control unit 54 controls the EPC valve 28 based on the signals indicating the coordinates of the acquired corrected passing point P1B, the discharge point P2, and the return point P3.

By controlling the EPC valve 28 by the EPC valve control unit 54, each hydraulic actuator is controlled so that the center of the arm top pin 15 in the left-right direction passes from the return point P3 through the corrected passing point P1B and reaches the unloading point P2 during automatic loading control (step S5: Figure 6). This enables automatic loading control in which interference between the bucket 8 and the loading target 200 is suppressed.

＜Effects＞
Next, the effects of this embodiment will be described.

In this embodiment, as shown in FIG. 4, a position shifted from the passing point P1A to the opposite side of the unloading point P2 is set as the corrected passing point P1B, and the coordinates of the corrected passing point P1B are calculated. The operation of the work machine 2 is then controlled so that it passes through the corrected passing point P1B when turning. This makes it possible to suppress interference between the bucket 8 and the loading target 200 during automatic loading control.

In this embodiment, as shown in FIG. 4, a position shifted from the passing point P1A on the opposite side of the earth unloading point P2 by half the dimension (W/2) of the width W (FIG. 1) in the left-right direction of the bucket 8 is set as the corrected passing point P1B. This makes it possible to further suppress interference between the bucket 8 and the loading target 200 during automatic loading control.

In addition, in this embodiment, a position shifted from the passing point P1A in the horizontal direction in a machine coordinate system based on the hydraulic excavator 100 is set as the corrected passing point P1B. This makes it possible to suppress interference between the bucket 8 and the loading target 200 during automatic loading control, even if the hydraulic excavator 100 is placed on a slope that is inclined with respect to the horizontal plane in the global coordinate system.

In this embodiment, as shown in FIG. 5, the automatic control system has an operation unit 25 that outputs a manual operation command to drive the actuator 29, and an instruction unit 24 that indicates the passing point P1A when the operation command is output to operate the work machine 2. This allows the operator to manually operate the work machine 2 and the rotating body 3 to identify the passing point P1A.

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

1 Main body, 2 Work machine, 3 Swivel body, 4 Cab, 4S Cab, 5 Traveling body, 5Cr Track, 5M Traveling motor, 6 Boom, 7 Arm, 8 Bucket, 9 Exterior cover, 10 Boom cylinder, 11 Arm cylinder, 12 Bucket cylinder, 13 Boom foot pin, 14 Boom top pin, 15 Arm top pin, 17 Bucket link, 20 Work machine attitude sensor, 21 Position and direction sensor, 21a Receiver, 22 Tilt sensor, 23 Detection sensor, 24 Indication unit, 25 Operation unit, 26 Input device, 27 Hydraulic pump, 28 EPC valve, 29 Actuator, 50 Controller, 51 Indication point identification unit, 51A Passing point identification unit, 51B Earth discharge point identification unit, 51C Return point identification unit, 52 Corrected passing point calculation unit, 53 Memory unit, 54 EPC valve control unit, 100 Hydraulic excavator, 200 loading target, 200A vessel, P1A passing point, P1B corrected passing point, P2 unloading point, P3 return point, R1, R2 movement trajectory, RX rotation axis, SE side edge.

Claims (7)

A rotating body that rotates;
A work machine attached to the rotating body and having a work tool;
a posture detection sensor for detecting a posture of the work machine;
a controller that identifies a discharge point and a passing point on a path that the work implement passes through when the rotating body rotates based on the detection results of the attitude detection sensor, sets a position shifted from the passing point to the opposite side of the discharge point as a corrected passing point, and controls the work implement to pass through the corrected passing point when rotating. The automatic control system for a work machine according to claim 1, wherein the controller sets the corrected passing point to a position shifted from the passing point by half the width of the implement on the opposite side of the earth removal point. The automatic control system for a work machine according to claim 1, wherein the controller sets the corrected passing point to a position horizontally shifted from the passing point in a machine coordinate system based on the work machine. The automatic control system for a work machine according to claim 1, which identifies the passing point as a point located above the side edge of the loading target on the path through which the work implement passes when the rotating body rotates. An actuator that drives the working machine;
an operation unit that outputs a manual operation command for driving the actuator;
5. The automatic control system for a work machine according to claim 1, further comprising: an instruction unit that indicates the passing point when the operation command is output to operate the work machine. A control method for a work machine including a rotating body and a work implement having a working tool attached to the rotating body, comprising:
A step of identifying an earth unloading point and a passing point on a path through which the work implement passes when the rotating body rotates based on a detection result of the attitude of the work implement;
setting a position shifted from the passing point to an opposite side to the earth unloading point in a top view as a corrected passing point;
and controlling the work implement so that it passes through the corrected passing point during a turn. 7. The control method for a work machine according to claim 6, wherein in the step of identifying the passing point, the passing point is identified based on a detection result of an attitude of the work machine at the time an operation signal based on manual operation is input.

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