EXCAVATOR AND CONTROL DEVICE FOR EXCAVATOR

Abstract

A control device for an excavator includes circuitry configured to control the excavator; and a sensor configured to detect information about a ground raised by excavation. The circuitry estimates presence or absence of a buried object based on at least one of an excavation reaction force calculated during excavation by an excavation attachment of the excavator or information detected by the sensor.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims priority to Japanese Patent Application No. 2023-218208, filed on Dec. 25, 2023, the entire contents of which are incorporated herein by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to an excavator and a control device for the excavator.

2. Description of Related Art

Conventionally, an excavator as a digging machine for excavating the ground is known. This excavator is configured to be able to excavate earth by moving an excavation attachment attached to the upper slewing body.

SUMMARY

According to an embodiment of the present disclosure, a control device for an excavator is provided.

The control device includes:

• • circuitry configured to control the excavator; and
  • a sensor configured to detect information about a ground raised by excavation,
  • wherein the circuitry estimates presence or absence of a buried object based on at least one of an excavation reaction force calculated during excavation by an excavation attachment of the excavator or information detected by the sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an excavator according to an embodiment of the present disclosure.

FIG. 2 is a side view of the excavator illustrating a relationship between an excavation attachment of the excavator of FIG. 1 and various physical quantities.

FIG. 3 is a diagram illustrating a configuration example of a basic system mounted on the excavator of FIG. 1.

FIG. 4 is a diagram illustrating a configuration example of an excavation control system mounted on the excavator of FIG. 1.

FIG. 5 is a cross-sectional view of a ground in which a water pipe is buried.

FIG. 6 is a graph illustrating a relationship between an excavation reaction force and an approach distance.

FIG. 7 is a diagram illustrating an example of an output image displayed on an image display unit.

FIG. 8 is a diagram illustrating another configuration example of an excavation control system.

FIG. 9 is a cross-sectional view of a ground in which a water pipe is buried.

FIG. 10 is a top view of an excavation attachment performing an excavation operation.

FIG. 11 is a schematic diagram illustrating a configuration example of a control system of the excavator.

DETAILED DESCRIPTION

However, when excavation work is performed by an excavator at a work site where a buried object, such as a water pipe, is buried in the ground, there is a possibility that the buried object is destroyed by mistake.

Accordingly, in view of the above-described case, it is desirable to provide a control device for an excavator capable of preventing a buried object from being destroyed during excavation work.

According to the above-described embodiment, a control device for an excavator capable of preventing a buried object from being destroyed during excavation work is provided.

First, an excavator (excavator 100) as a digging machine according to an embodiment of the present disclosure will be described with reference to FIG. 1. FIG. 1 is a side view of the excavator 100 according to an embodiment of the present disclosure. An upper slewing body 3 is slewably mounted on a lower traveling body 1 of the excavator 100 illustrated in FIG. 1 via a slewing mechanism 2. A boom 4 is attached to the upper slewing body 3, an arm 5 is attached to the tip of the boom 4, and a bucket 6 is attached to a tip of the arm 5. The boom 4, the arm 5, and the bucket 6 as work elements constitute an excavation attachment AT which is an example of an attachment. The boom 4 is driven by a boom cylinder 7, the arm 5 is driven by an arm cylinder 8, and the bucket 6 is driven by a bucket cylinder 9. The upper slewing body 3 is provided with a cabin 10, and a power source, such as an engine 11, is mounted in the upper slewing body 3.

An attitude detection device M1 is attached to the excavation attachment AT. The attitude detection device M1 is an example of a detection device which is a device that detects information about an excavation reaction force. In particular, the attitude detection device M1 is configured to be able to detect the attitude of the excavation attachment AT. In the illustrated example, the attitude detection device M1 includes a boom angle sensor M1a, an arm angle sensor M1b, and a bucket angle sensor M1c.

The boom angle sensor M1a is a sensor that acquires a boom angle, and includes, for example, a rotation angle sensor that detects a rotation angle of a boom foot pin, a stroke sensor that detects a stroke amount of the boom cylinder 7, and an inclination (accelerator) sensor that detects an inclination angle of the boom 4. The same applies to the arm angle sensor M1b and the bucket angle sensor M1c.

The upper slewing body 3 is provided with a cabin 10 as an operator's seat and a power source, such as an engine 11, is mounted in the upper slewing body 3. The power source may be an electric motor. An object detection device 70 and the like are attached to the upper slewing body 3. An operation device 26, a controller 30, a display device 40, a sound output device 45, and the like are provided inside the cabin 10. In this specification, for convenience, a side of the upper slewing body 3 on which the boom 4 is mounted is referred to as a front side, and a side on which the counterweight is mounted is referred to as a rear side.

The object detection device 70 is configured to detect an object existing around the excavator 100. The object is, for example, a person, an animal, a vehicle, another construction machine, a building, a hole, or the like. The object detection device 70 is, for example, an ultrasonic sensor, a millimeter wave radar, an imaging device, an infrared sensor, or the like. The imaging device is, for example, a monocular camera, a stereo camera, a Light Detection And Ranging (LiDAR), or a range image sensor. In the illustrated example, the object detection device 70 includes a rear camera 70B attached to the rear end of the upper surface of the upper slewing body 3, a front camera 70F attached to the front end of the upper surface of the cabin 10, a left camera 70L attached to the left end of the upper surface of the upper slewing body 3, and a right camera 70R attached to the right end of the upper surface of the upper slewing body 3.

The object detection device 70 may be configured to be able to detect a predetermined object (for example, a person) in a predetermined area set around the excavator 100. For example, the object detection device 70 may be configured to be able to detect a person and an object other than a person in a distinguishable manner.

FIG. 2 is a side view of the excavator 100 illustrating various physical quantities related to the excavation attachment AT. The boom angle sensor M1a acquires, for example, a boom angle θ1. The boom angle θ1 is an angle of a line segment P1-P2 connecting a boom foot pin position P1 and an arm coupling pin position P2 with respect to the horizontal line in an XZ plane. The arm angle sensor M1b acquires, for example, an arm angle θ2. The arm angle θ2 is an angle of a line segment P2-P3 connecting the arm coupling pin position P2 and a bucket coupling pin position P3 with respect to the horizontal line in the XZ plane. The bucket angle sensor M1c acquires, for example, a bucket angle θ3. The bucket angle θ3 is an angle of a line segment P3-P4 connecting a bucket coupling pin position P3 and a bucket claw tip position P4 with respect to the horizontal line in the XZ plane. The bucket angle θ3 may be calculated based on the operation content of the operation device 26. For example, the bucket angle θ3 may be calculated based on the outputs of pilot pressure sensors 15a and 15b, and the like. In this case, the bucket angle sensor M1c may be omitted.

Next, a basic system of the excavator 100 will be described with reference to FIG. 3. The basic system of the excavator 100 mainly includes the engine 11, a main pump 14, a pilot pump 15, the control valve unit 17, the operation device 26, the controller 30, the display device 40, the sound output device 45, an engine control device 74, an operation mode changeover switch 75, a buried object detection mode switch 76, an attitude detection device M1, an excavation pressure sensor S1, and the like.

The engine 11 is a drive source of the excavator 100, and is, for example, a diesel engine that operates to maintain a predetermined rotation speed. An output shaft of the engine 11 is connected to respective input shafts of the main pump 14 and the pilot pump 15.

The main pump 14 is a hydraulic pump that supplies hydraulic fluid to the control valve unit 17 via a hydraulic fluid line 16, and is, for example, a swash-plate-type variable displacement hydraulic pump. In a swash-plate-type variable displacement hydraulic pump, the stroke length of a piston, which determines the displacement volume, changes in response to a change in the swash plate tilt angle, thereby changing the discharge flow rate per rotation. The swash plate tilt angle is controlled by a regulator 14a. The regulator 14a changes the swash plate tilt angle in response to a change in the control current from the controller 30. For example, the regulator 14a increases the swash plate tilt angle in response to an increase in the control current to increase the delivery flow rate of the main pump 14. Alternatively, the regulator 14a reduces the swash plate tilt angle in response to a decrease in the control current to reduce the delivery flow rate of the main pump 14. A discharge pressure sensor 14b detects the discharge pressure of the main pump 14. An oil temperature sensor 14c detects the temperature of the hydraulic fluid sucked by the main pump 14.

The pilot pump 15 is a hydraulic pump for supplying the hydraulic fluid to various hydraulic control devices, such as the operation device 26, via a pilot line 25, and is, for example, a fixed disarrangement hydraulic pump.

The control valve unit 17 is configured to control the flow of hydraulic fluid related to the hydraulic actuator. In the illustrated example, the control valve unit 17 includes a plurality of flow rate control valves. The control valve unit 17 selectively supplies the hydraulic fluid received from the main pump 14 through the hydraulic fluid line 16 to one or a plurality of hydraulic actuators in accordance with a change in pressure (pilot pressure) corresponding to the operation direction and operation amount of the operation device 26. The hydraulic actuators include, for example, the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, a left traveling hydraulic motor 1A, a right traveling hydraulic motor 1B, and the slewing hydraulic motor 2A. In the illustrated example, the hydraulic motors (the left traveling hydraulic motor 1A, the right traveling hydraulic motor 1B, and the slewing hydraulic motor 2A) are swash-plate-type piston motors. However, at least one of the hydraulic motors may be an electric motor.

The operation device 26 is a device used by the operator to operate the hydraulic actuators, and includes a lever 26A, a lever 26B, a pedal 26C, and the like. The operation device 26 receives the hydraulic fluid supplied from the pilot pump 15 via the pilot line 25, and generates a pilot pressure. The operation device 26 applies the pilot pressure to the pilot port of the corresponding flow rate control valve through the pilot line 25a. The pilot pressure changes in accordance with the operation direction and the operation amount of the operation device 26. The operation device 26 may be remotely operated. In this case, the operation device 26 generates the pilot pressure in accordance with the information about the operation direction and the operation amount received via wireless communication.

The operation device 26 may be an electric operation device instead of the hydraulic operation device as described above. In this case, an electromagnetic valve for adjusting the pilot pressure may be disposed between the flow rate control valve in the control valve unit 17 and the pilot pump 15. Information about the operation direction and the operation amount of the electric operation device is transmitted as an electric signal from the electric operation device to the controller 30. The controller 30 can adjust the magnitude of the pilot pressure acting on the flow rate control valve by adjusting the opening area of the electromagnetic valve in accordance with the electric signal received from the electric operation device.

The controller 30 is a control device for controlling the excavator 100. In the illustrated example, the controller 30 is configured by a computer including circuitry, or a CPU, a volatile storage device, a nonvolatile storage device, and the like. The CPU of the controller 30 reads programs corresponding to various functions from the nonvolatile storage device, loads the programs into the volatile storage device, and executes the programs, thereby implementing functions corresponding to the programs.

For example, the controller 30 implements a function of controlling the discharge flow rate of the main pump 14. In detail, the controller 30 changes the magnitude of the control current to the regulator 14a according to the hydraulic pressure in the negative control valve, and controls the delivery flow rate of the main pump 14 via the regulator 14a.

The display device 40 is a device that displays various types of information, and is disposed in the vicinity of an operator's seat in the cabin 10. In the illustrated example, the display device 40 includes an image display unit 41 and an input unit 42. The image display unit 41 is a liquid crystal display. The input unit 42 is a membrane switch. An operator can input information and commands to the controller 30 using the input unit 42. Further, the operator can grasp the operation state and the control information of the excavator 100 by viewing the image display unit 41. The display device 40 is connected to the controller 30 via a communication network, such as a Controller Area Network (CAN). However, the display device 40 may be connected to the controller 30 via a dedicated line.

The display device 40 operates by receiving power supplied from a storage battery 90. In the illustrated example, the storage battery 90 is charged with power generated by an alternator 11a. The electric power of the storage battery 90 is also supplied to devices other than the controller 30 and the display device 40, such as an electrical component 72 of the excavator 100. A starter 11b of the engine 11 can be driven by power from the storage battery 90 to start the engine 11.

The sound output device 45 is a device that outputs sound information. In the illustrated example, the sound output device 45 is a speaker disposed in the vicinity of the operator's seat in the cabin 10. The sound output device 45 may be a buzzer.

The engine control device 74 is a device that controls the engine 11. The engine control device 74 controls, for example, the fuel injection amount and the like such that the engine speed set via the input device is implemented.

The engine 11 is controlled by the engine control device 74. The engine control device 74 transmits various kinds of information indicating the state of the engine 11 (for example, information about physical quantities such as information indicating a coolant temperature detected by a coolant temperature sensor 11c) to the controller 30. The controller 30 stores the information in a temporary storage unit (memory) 30a, and can transmit the information to the display device 40 or the like as required. The same applies to data indicating the swash plate tilt angle output by the regulator 14a, data indicating the discharge pressure of the main pump 14 output by the discharge pressure sensor 14b, data indicating the hydraulic fluid temperature output by the oil temperature sensor 14c, and data indicating pilot pressure output by the pilot pressure sensors 15a and 15b.

The operation mode changeover switch 75 is a switch for switching an operation mode of the excavator 100, and is provided in the cabin 10. In the illustrated example, the operator can switch between a manual (M) mode and a semi-automatic (SA) mode by operating the operation mode changeover switch 75. The controller 30 is configured to switch the operation mode of the excavator 100 in accordance with, for example, the output of the operation mode changeover switch 75. FIG. 3 illustrates a state in which the SA mode is selected by the operation mode changeover switch 75.

The M mode is a mode in which the excavator 100 is operated in accordance with the content of an operation input to the operation device 26 by the operator. For example, the operation mode is a mode in which the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, and the like are operated in accordance with the content of the operation input to the operation device 26 by the operator. The SA mode is a mode in which the excavator 100 is automatically operated independent of the content of the operation input to the operation device 26 when a predetermined condition is satisfied. For example, the SA mode is a mode in which at least one of the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 is automatically operated independent of the content of the operation input to the operation device 26 when a predetermined condition is satisfied. The operation mode changeover switch 75 may be configured to be able to switch three or more operation modes.

The buried object detection mode switch 76 is a switch for activating the buried object detection function, and is provided in the cabin 10. The buried object detection function is a function of detecting a buried object in the ground to be excavated. In the illustrated example, the buried object detection function is configured to detect the presence or absence of a buried object based on the excavation reaction force. In the illustrated example, the operator can switch between activation and deactivation of the buried object detection function by operating the buried object detection mode switch 76. The controller 30 is configured to switch between activation and deactivation of the buried object detection function in accordance with, for example, an output of the buried object detection mode switch 76. Specifically, the controller 30 is configured to activate the buried object detection function in response to an activation command from the buried object detection mode switch 76, and to deactivate the buried object detection function in response to a deactivation command from the buried object detection mode switch 76. However, the controller 30 may activate the buried object detection function when it is determined that the excavation operation is being performed based on the attitude of the excavation attachment AT or the like, independent of the operation of the buried object detection mode switch 76. In this case, the controller 30 may continuously execute the buried object detection function, for example, from the time point when the excavation operation is started to the time point when the boom raising operation is performed.

The excavation pressure sensor S1 is an example of a detection device that detects information about an excavation reaction force, and detects a pressure of a hydraulic fluid in hydraulic cylinder, such as the boom cylinder 7, and outputs the detected pressure to the controller 30. In the illustrated example, the excavation pressure sensor S1 includes excavation pressure sensors S11 to S18. Specifically, the excavation pressure sensor S11 detects a boom bottom pressure, which is a hydraulic pressure of the hydraulic fluid in a bottom side hydraulic chamber of the boom cylinder 7. The excavation pressure sensor S12 detects a boom rod pressure, which is a hydraulic pressure of the hydraulic fluid in a rod side hydraulic chamber of the boom cylinder 7. Similarly, the excavation pressure sensor S13 detects an arm bottom pressure, the excavation pressure sensor S14 detects an arm rod pressure, the excavation pressure sensor S15 detects a bucket bottom pressure, and the excavation pressure sensor S16 detects a bucket rod pressure. The excavation pressure sensor S17 detects a left slewing pressure, which is a hydraulic pressure of the hydraulic fluid at a first port (left port) of the slewing hydraulic motor 2A, and the excavation pressure sensor S18 detects a right slewing pressure, which is a hydraulic pressure of the hydraulic fluid at a second port (right port) of the slewing hydraulic motor 2A.

A control valve E1 is operated in response to a command from the controller 30. In the illustrated example, the control valve E1 is used to forcibly operate the flow rate control valves related to predetermined hydraulic cylinders independent of the content of the operation input to the operation device 26. When the above-described electric operation device is employed, the control valve E1 corresponds to an electromagnetic valve disposed between the flow rate control valves and the pilot pump 15.

FIG. 4 is a diagram illustrating a configuration example of an excavation control system mounted on the excavator 100 of FIG. 1. The excavation control system is mainly configured by the attitude detection device M1, the excavation pressure sensor S1, the operation mode changeover switch 75, the buried object detection mode switch 76, the controller 30, the control valve E1, the display device 40, and the sound output device 45. The controller 30 includes an excavation reaction force calculation unit 31 and a buried object detection unit 32.

The excavation reaction force calculation unit 31 is a functional element that calculates an excavation reaction force. The excavation reaction force calculation unit 31 is configured to calculate an excavation reaction force based on at least the output of the excavation pressure sensor S1. In the illustrated example, the excavation reaction force calculation unit 31 calculates the excavation reaction force based on outputs of the excavation pressure sensor S1 and the attitude of the excavation attachment AT detected by the attitude detection device M1. The excavation reaction force calculation unit 31 may additionally use an output of a body inclination sensor. The body inclination sensor may be configured by, for example, an acceleration sensor or a gyro sensor.

The output of the excavation pressure sensor S1 includes, for example, at least one of a boom bottom pressure (P11), a boom rod pressure (P12), an arm bottom pressure (P13), an arm rod pressure (P14), a bucket bottom pressure (P15), and a bucket rod pressure (P16) detected by the excavation pressure sensors S11 to S16.

The excavation reaction force calculation unit 31 may calculate a cylinder thrust based on the output of the excavation pressure sensor S1. The cylinder thrust is calculated, for example, based on an excavation pressure and a pressure receiving area of the piston sliding in the cylinder. The cylinder thrust includes, for example, a boom cylinder thrust (f1), an arm cylinder thrust (f2), and a bucket cylinder thrust (f3). Specifically, as illustrated in FIG. 2, the boom cylinder thrust (f1) is represented by the difference (P11×A11−P12×A12) between a cylinder extension force, which is a product (P11×A11) of the boom bottom pressure (P11) and a pressure-receiving area (A11) of the piston in a boom bottom side oil chamber, and a cylinder contraction force, which is a product (P12×A12) of the boom rod pressure (P12) and a pressure-receiving area (A12) of the piston in a boom rod side oil chamber. The same applies to the arm cylinder thrust (f2) and the bucket cylinder thrust (f3).

The excavation reaction force calculation unit 31 may calculate an excavation torque based on the attitude of the excavation attachment AT and the cylinder thrust. As illustrated in FIG. 2, the magnitude of a bucket excavation torque (T3) is represented by a value obtained by multiplying the magnitude of the bucket cylinder thrust (f3) by a distance G3 between the line of action of the bucket cylinder thrust (f3) and the bucket coupling pin position P3. The distance G3 is a function of the bucket angle θ3, and is an example of a link gain. The same applies to the boom excavation torque (T1) and an arm excavation torque (12). The distance G1 is a distance between the line of action of the boom cylinder thrust (f1) and the boom foot pin position P1, and the distance G2 is a distance between the line of action of the arm cylinder thrust (f2) and the arm coupling pin position P2.

The excavation reaction force is calculated as, for example, a product of a mechanism function having the boom angle θ1, the arm angle θ2, and the bucket angle θ3 as arguments and a function having a boom excavation torque (T1), the arm excavation torque (12), and the bucket excavation torque (13) as arguments as illustrated in FIG. 2. The function having the boom excavation torque (T1), the arm excavation torque (12), and the bucket excavation torque (13) as arguments may be a function having the boom cylinder thrust (f1), the arm cylinder thrust (f2), and the bucket cylinder thrust (f3) as arguments.

The function having the boom angle θ1, the arm angle θ2, and the bucket angle θ3 as arguments may be based on a force balance equation, may be based on a Jacobian, or may be based on the principle of virtual work.

In this way, the value of the excavation reaction force is derived based on the current detection values of the various sensors. However, the detection value of the excavation pressure sensor S1 may be used as a value of the excavation reaction force as it is. Alternatively, a value of the cylinder thrust calculated based on the detection value of the excavation pressure sensor S1 may be used as the value of the excavation reaction force. Alternatively, a value of the excavation torque calculated from the value of the cylinder thrust calculated based on the detection value of the excavation pressure sensor S1 and a value related to the attitude of the excavation attachment AT derived based on the detection value of the attitude detection device M1 may be used as the value of the excavation reaction force.

The excavation reaction force calculation unit 31 may calculate an excavation reaction force acting in the slewing direction based on the outputs of the excavation pressure sensor S17 and the excavation pressure sensor S18. In the illustrated example, the upper slewing body 3 attempts to slew in the left direction when a left slewing pressure (P17) detected by the excavation pressure sensor S17 is greater than a right slewing pressure (P18) detected by the excavation pressure sensor S18. Further, the upper slewing body 3 attempts to slew in the right direction when the right slewing pressure (P18) detected by the excavation pressure sensor S18 is greater than the left slewing pressure (P17) detected by the excavation pressure sensor S17. The excavation reaction force calculation unit 31 may calculate, for example, the left slewing pressure (P17) as the excavation reaction force acting in the left slewing direction in a case where the left slewing pressure (P17) is greater than the right slewing pressure (P18). Further, the excavation reaction force calculation unit 31 may calculate, for example, the right slewing pressure (P18) as the excavation reaction force acting in the right slewing direction in the case where the right slewing pressure (P18) is greater than the left slewing pressure (P17). Note that, when a slewing electric motor is mounted instead of the slewing hydraulic motor 2A, the excavation reaction force calculation unit 31 may calculate the excavation reaction force acting in the slewing direction based on information about electric power such as an orientation and magnitude of an electric current supplied to the slewing electric motor.

The buried object detection unit 32 is configured to be able to detect a buried object based on information about the excavation reaction force. In the illustrated example, the buried object detection unit 32 is configured to be able to estimate (determine) the presence or absence of a buried object based on the excavation reaction force calculated by the excavation reaction force calculation unit 31.

Then, for example, when the buried object detection unit 32 estimates that the buried object is present, the buried object detection unit 32 outputs a control command to the control valve E1.

The control valve E1 is configured to forcibly operate the flow rate control valves related to the predetermined hydraulic cylinders to forcibly extend and contract the predetermined hydraulic cylinders independent of the content of the operation input to the operation device 26 when receiving the control command from the buried object detection unit 32. In the illustrated example, the control valve E1 is configured to be able to forcibly extend the boom cylinder 7 by forcibly moving the flow rate control valve related to the boom cylinder 7 even when the boom operation lever is not operated, for example. As a result, the control valve E1 can make the excavation depth shallow by forcibly raising the boom 4. Alternatively, even when the arm operation lever is operated, the control valve E1 may forcibly deactivate the arm cylinder 8 by forcibly moving the flow rate control valve related to the arm cylinder 8. In this case, the control valve E1 can prevent contact between the bucket 6 and the buried object by forcibly deactivating the arm 5. In this way, the control valve E1 can prevent the contact between the excavation attachment AT and the buried object by forcibly extending or contracting, or deactivating at least one of the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 in response to the control command from the buried object detection unit 32.

The buried object detection unit 32 may output a control command to the display device 40 when estimating that there is a buried object. The display device 40 may be configured to display an estimated position of the buried object when receiving a control command from the buried object detection unit 32. For example, the display device 40 may display a virtual viewpoint image representing a state when the excavator 100 is viewed from a virtual viewpoint directly above the excavator 100, and may superimpose and display a figure related to an actually invisible buried object buried in the ground on the virtual viewpoint image. In the illustrated example, the virtual viewpoint image is generated based on images acquired by the rear camera 70B, the left camera 70L, and the right camera 70R. Note that an image acquired by the front camera 70F may be additionally used when the virtual viewpoint image is synthesized. Alternatively, the display device 40 may display an image representing a cross section of the ground where the excavator 100 is located, and may superimpose and display a figure related to an actually invisible buried object buried in the ground on the virtual viewpoint image.

The buried object detection unit 32 may output a control command to the sound output device 45 when estimating that the buried object is present. The sound output device 45 may output a voice message for notifying the operator of the presence of the buried object when receiving the control command from the buried object detection unit 32. Alternatively, the sound output device 45 may output an alarm sound for notifying the operator of the presence of the buried object.

The controller 30 may be configured to activate the buried object detection function in response to an activation command from the buried object detection mode switch 76. In the illustrated example, when the buried object detection function is activated, the buried object detection unit 32 can estimate the presence or absence of the buried object based on the excavation reaction force calculated by the excavation reaction force calculation unit 31. On the other hand, the controller 30 may be configured to deactivate the buried object detection function in response to a deactivation command from the buried object detection mode switch 76. In the illustrated example, when the buried object detection function is deactivated, the buried object detection unit 32 does not estimate the presence or absence of a buried object. This is to prevent the control command from being output to the control valve E1, the display device 40, or the sound output device 45 because the presence of a buried object is incorrectly estimated in response to fluctuations in the excavation reaction force, even though it is clear that there is no buried object.

When the buried object detection function is deactivated, the excavation reaction force calculation unit 31 may be configured not to calculate the excavation reaction force. This is to reduce the calculation load.

In the illustrated example, the buried object detection function is configured to be executed even when the operation mode of the excavator 100 is any of the M (manual) mode and the SA (semi-automatic) mode. However, the buried object detection function may be configured to be executed only when the SA (semi-automatic) mode is selected. This is because, when the SA (semi-automatic) mode is selected, the operator can move the excavation attachment AT along a target trajectory set in advance, and as a result, the detection accuracy of the buried object can be improved. When the SA (semi-automatic) mode is selected, one excavation operation for finding a buried object (a series of operations from the insertion of the claw tip of the bucket 6 into the ground to the separation of the bucket 6 from the ground) may be automatically executed, for example, when the buried object detection mode switch 76 is operated. That is, each excavation operation may be automatically executed every time the buried object detection mode switch 76 is operated.

The target trajectory is, for example, a trajectory to be followed by a predetermined portion of the excavation attachment AT. The predetermined portion of the excavation attachment AT is, for example, the claw tip of the bucket 6.

Next, the movement of the excavator 100 when the operator of the excavator 100 finds a water pipe U1 as the buried object will be described with reference to FIG. 5. FIG. 5 illustrates a cross section of the ground in which a water pipe U1 is buried. The excavator 100 is located on the ground.

In the example illustrated in FIG. 5, the operator of the excavator 100 first operates the operation mode changeover switch 75 to switch the operation mode of the excavator 100 to the SA (semi-automatic) mode. Then, the operator manually operates the operation device 26 to move the claw tip of the bucket 6 to a desired position. The desired position is, for example, a position directly above a point into which the claw tip of the bucket 6 is to be inserted. After moving the claw tip of the bucket 6 to the desired position, the operator operates the buried object detection mode switch 76 to activate the buried object detection function.

In the illustrated example, when the buried object detection function is activated in the SA (semi-automatic) mode, the controller 30 autonomously operates the excavation attachment AT. Specifically, the controller 30 automatically extends and contracts at least one of the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 so as to move the predetermined portion of the excavation attachment AT along a target trajectory TP set in advance. However, the controller 30 may be configured not to autonomously operate the excavation attachment AT as in the case of the M (manual) mode even when the buried object detection function is activated. In this case, the excavation attachment AT operates in accordance with the operation content of the operation device 26 by the operator.

In the example illustrated in FIG. 5, the operator activates the buried object detection function after moving the claw tip of the bucket 6 to a first position PS1. The first position PS1 is a position on a ground ES before excavation is performed. FIG. 5 illustrates the ground ES before excavation is performed in broken lines. When the buried object detection function is activated, the controller 30 automatically operates the excavation attachment AT such that the claw tip of the bucket 6 moves along a preset first target trajectory TP1 (a dash-dot line).

Then, the excavation reaction force calculation unit 31 repeatedly calculates the excavation reaction force based on the output of the attitude detection device M1 and the output of the excavation pressure sensor S1 at a predetermined control cycle when the claw tip of the bucket 6 moves along the first target trajectory TP1.

The buried object detection unit 32 repeatedly estimates the presence or absence of a buried object based on the excavation reaction force calculated by the excavation reaction force calculation unit 31 at the predetermined control cycle when the claw tip of the bucket 6 moves along the first target trajectory TP1.

When the claw tip of the bucket 6 reaches the end of the first target trajectory TP1, the controller 30 stops the autonomous operation of the excavation attachment AT. This means that the buried object detection unit 32 does not detect the buried object up to the claw tip of the bucket 6 reaching the end of the first target trajectory TP1.

Thereafter, the operator operates the buried object detection mode switch 76 to deactivate the buried object detection function. The controller 30 may deactivate the buried object detection function when the operator manually operates the operation device 26 to perform the boom raising operation or the boom raising and slewing operation. Thereafter, the operator performs the earth discharging operation and the boom lowering and slewing operation, and then moves the claw tip of the bucket 6 to a next desired position in order to perform a next excavation operation. In the example illustrated in FIG. 5, the operator discharges the earth in the bucket 6 by manual operation, and then moves the claw tip of the bucket 6 to a second position PS2. At least one of the discharging of the earth in the bucket 6 and the movement of the bucket 6 to the second position PS2 may be automatically performed. The second position PS2 is a position on a first exposed surface exposed by the previous excavation operation. Specifically, the second position PS2 on the first exposed surface is a position at a depth D1 from the ground ES before the excavation is started, and is a position substantially directly below the first position PS1. The operator moves the claw tip of the bucket 6 to the second position PS2 and then activates the buried object detection function. When the buried object detection function is activated, the controller 30 automatically operates the excavation attachment AT such that the claw tip of the bucket 6 moves along a preset second target trajectory TP2 (a dash-dot line).

Then, the excavation reaction force calculation unit 31 repeatedly calculates the excavation reaction force based on the output of the attitude detection device M1 and the output of the excavation pressure sensor S1 at the predetermined control cycle when the claw tip of the bucket 6 moves along the second target trajectory TP2.

The buried object detection unit 32 repeatedly estimates the presence or absence of the buried object based on the excavation reaction force calculated by the excavation reaction force calculation unit 31 at the predetermined control cycle when the claw tip of the bucket 6 moves along the second target trajectory TP2.

When the claw tip of the bucket 6 reaches the end of the second target trajectory TP2, the controller 30 stops the autonomous operation of the excavation attachment AT. This means that the buried object detection unit 32 does not detect the buried object until the claw tip of the bucket 6 reaches the end of the second target trajectory TP2.

Thereafter, the operator operates the buried object detection mode switch 76 to deactivate the buried object detection function. The controller 30 may deactivate the buried object detection function when the operator manually operates the operation device 26 to perform the boom raising operation or the boom raising and slewing operation.

Thereafter, the operator performs the earth discharging operation and the boom lowering and slewing operation, and then moves the claw tip of the bucket 6 to a next desired position in order to perform a next excavation operation. In the example illustrated in FIG. 5, the operator moves the claw tip of the bucket 6 to a third position PS3. The third position PS3 is a position on the second exposed surface exposed by the previous excavation operation. Specifically, the third position PS3 on the second exposed surface is located at a depth D2 from the first exposed surface and is located substantially directly below the second position PS2. In the example illustrated in FIG. 5, the depth D2 is the same depth as the depth D1. The operator activates the buried object detection function after moving the claw tip of the bucket 6 to the third position PS3. When the buried object detection function is activated, the controller 30 automatically operates the excavation attachment AT such that the claw tip of the bucket 6 moves along a preset third target trajectory TP3 (dash-dot line).

Then, the excavation reaction force calculation unit 31 repeatedly calculates the excavation reaction force based on the output of the attitude detection device M1 and the output of the excavation pressure sensor S1 at the predetermined control cycle when the claw tip of the bucket 6 moves along the third target trajectory TP3.

The buried object detection unit 32 repeatedly estimates the presence or absence of a buried object based on the excavation reaction forces calculated by the excavation reaction force calculation unit 31 at the predetermined control cycle when the claw tip of the bucket 6 moves along the third target trajectory TP3.

In the example illustrated in FIG. 5, the buried object detection unit 32 estimates that the buried object is present when the claw tip of the bucket 6 reaches a fourth position PS4. The fourth position PS4 is a position at a depth D3 from the second exposed surface and is a position on the third target trajectory TP3. In the example illustrated in FIG. 5, the depth D3 is the same depth as each of the depth D1 and the depth D2. The fourth position PS4 is a position at which the distance between the water pipe U1 and the claw tip of the bucket 6 in the direction along the third target trajectory TP3 becomes a value AD1. In the example illustrated in FIG. 5, the direction along the third target trajectory TP3 is a horizontal direction.

Here, the details of the process of estimating the presence or absence of the buried object by the buried object detection unit 32 based on the output of the excavation reaction force calculation unit 31 will be described with reference to FIG. 6. FIG. 6 is a graph illustrating a relationship between an excavation reaction force F and an approach distance AD. A vertical axis of FIG. 6 corresponds to the excavation reaction force F calculated by the excavation reaction force calculation unit 31, and a horizontal axis of FIG. 6 corresponds to the approach distance AD. In the example illustrated in FIG. 5, the approach distance AD is a distance between the current position of the claw tip of the bucket 6 and the water pipe U1 in the direction along the target trajectory TP. FIG. 6 illustrates that the approach distance AD decreases from left to right on the horizontal axis until the approach distance AD reaches a value of zero. That is, the claw tip of the bucket 6, when the approach distance AD is at a value AD0, is located farther from the water pipe U1 than when the approach distance AD is at the value AD1.

Specifically, a first transition TL1 indicated by a dash-dot line in FIG. 6 indicates a relationship between the excavation reaction force and the approach distance AD repeatedly calculated at a predetermined control cycle when the excavation attachment AT operates autonomously or semi-autonomously to cause the claw tip of the bucket 6 to move along the first target trajectory TP1 (see FIG. 5). In addition, a second transition TL2 indicated by a dotted line in FIG. 6 indicates a relationship between the excavation reaction force and the approach distance AD repeatedly calculated at a predetermined control cycle when the excavation attachment AT operates autonomously or semi-autonomously to cause the claw tip of the bucket 6 to move along the second target trajectory TP2 (see FIG. 5). A third transition TL3 indicated by a solid line in FIG. 6 indicates a relationship between the excavation reaction force and the approach distance AD repeatedly calculated at a predetermined control cycle when the excavation attachment AT operates autonomously or semi-autonomously to cause the claw tip of the bucket 6 to move along the third target trajectory TP3 (see FIG. 5).

All the first to third transitions TL1 to TL3 illustrate states in which the excavation reaction force F increases at a substantially constant increase rate as the approach distance AD decreases. This is because the amount of earth taken into the bucket 6 increases as the bucket 6 approaches the body (upper slewing body 3).

In the first transition TL1 and the second transition TL2, an increase tendency of the excavation reaction force F continues at substantially the same increase rate both when the approach distance AD approaches the value zero and when the approach distance AD exceeds the value zero and moves away from the value zero. This is because the water pipe U1 is not present on the target trajectory TP (the first target trajectory TP1 and the second target trajectory TP2). The points on the first transition TL1 and the second transition TL2 (the values of the excavation reaction forces F) when the approach distance AD is zero mean values of the excavation reaction forces F when the claw tip of the bucket 6 is directly above the water pipe U1.

On the other hand, the increase rate of the third transition TL3 significantly changes (increases) at the time point when the approach distance AD reaches the value AD0. This is because the water pipe U1 is present on the third target trajectory TP3, and the earth between the bucket 6 and the water pipe U1 is compressed between the bucket 6 and the water pipe U1 as the claw tip of the bucket 6 approaches the water pipe U1.

FIG. 6 illustrates a state in which the excavation reaction force F becomes a value F0 when the approach distance AD is at the value AD0, and the excavation reaction force F becomes the value F1 when the approach distance AD is at the value AD1. FIG. 5 illustrates a state in which the approach distance AD becomes the value AD1 when the claw tip of the bucket 6 reaches the fourth position PS4 on the third target trajectory TP3.

In the illustrated example, the buried object detection unit 32 is configured to estimate that a buried object is present when the value of the excavation reaction force F exceeds a predetermined excavation reaction force threshold Ft. The predetermined excavation reaction force threshold Ft becomes a value stored in advance in a nonvolatile storage device or the like. However, the predetermined excavation reaction force threshold Ft may be a value that is dynamically set. For example, the predetermined excavation reaction force threshold Ft may be derived based on the value of the excavation reaction force F calculated during the preceding excavation operation.

Alternatively, the buried object detection unit 32 may be configured to estimate that a buried object is present when the average increase rate of the excavation reaction force F with respect to the approach distance AD exceeds a predetermined threshold.

The buried object detection unit 32 may be configured to estimate the presence or absence of a buried object based on the magnitude of a horizontal component or a vertical component of the excavation reaction force F.

Here, an example of an image displayed on the image display unit 41 of the display device 40 when the buried object detection unit 32 detects the water pipe U1 will be described with reference to FIG. 7. FIG. 7 is a diagram illustrating an example of an output image displayed on the image display unit 41. As illustrated in FIG. 7, the image display unit 41 schematically displays a relationship between the bucket 6 and a buried object (water pipe U1). The buried object, such as a water pipe U1, in the ground is not actually visible. Therefore, in the example illustrated in FIG. 7, the controller 30 acquires position information of the buried object from construction information. The construction information is stored in advance in, for example, a nonvolatile storage device. The construction information may include two-dimensional or three-dimensional construction drawing data in addition to the position information of the buried object.

Specifically, FIG. 7 schematically illustrates the relationship between the excavation attachment AT and the buried object when viewed from directly above by a bucket figure G11, an arm figure G12, a buried object figure G13, and an approach restriction line G14. The output image illustrated in FIG. 7 illustrates a state immediately after the fourth excavation operation is started after the water pipe U1 is detected by the third excavation operation illustrated in FIG. 5. In addition, the output image illustrated in FIG. 7 indicates that the finer (denser) the dot pattern is, the larger (deeper) the excavation depth is. The output image illustrated in FIG. 7 is displayed on the entire screen of the image display unit 41, but may be displayed on a part of the image display unit 41.

The bucket figure G11 is a figure representing a current state of the bucket 6. The arm figure G12 is a figure representing a current state of the arm 5. The display position, display shape, display size, and the like of each of the bucket figure G11 and the arm figure G12 are determined based on the output of the attitude detection device M1. The output image may include a boom figure which is a figure representing a current state of the boom 4.

The buried object figure G13 is a figure representing a position and a size of the buried object. In the example illustrated in FIG. 7, the buried object figure G13 includes a buried object figure G13A generated based on the construction information and a buried object figure G13B generated based on a detection result of the buried object detection unit 32.

The approach restriction line G14 is a figure representing a position and a size of an approach restriction area set around the buried object. In the example illustrated in FIG. 7, as in the buried object figure G13, the approach restriction line G14 includes an approach restriction line G14A corresponding to the buried object figure G13A generated based on the construction information and an approach restriction line G14B corresponding to the buried object figure G13B generated based on a detection result of the buried object detection unit 32.

The display device 40 does not display the buried object figure G13B and the approach restriction line G14B until the buried object is detected by the buried object detection unit 32. This is because the display device 40 cannot specify display positions of the buried object figure G13B and the approach restriction line G14B. On the other hand, after the buried object is detected by the buried object detection unit 32, the display device 40 may omit the display of the buried object figure G13A and the approach restriction line G14A. This is because the buried object represented by the buried object figure G13A is estimated to be actually present at the position represented by the buried object figure G13B.

The approach restriction area is an area where the entry of the predetermined portion of the excavation attachment AT is restricted. In the example illustrated in FIG. 7, the approach restricted area is a space including a space where it is determined that the buried object is present. The controller 30 attracts the operator's attention such that, for example, the predetermined portion of the excavation attachment AT does not enter the approach restriction area. Specifically, the controller 30 may inform the operator of the magnitude of the distance between the claw tip of the bucket 6 and the buried object by using, for example, intermittent sound from the sound output device 45. In this case, the controller 30 may shorten the interval of the intermittent sound as the distance decreases. Further, when the claw tip of the bucket 6 enters the approach restriction area, the controller 30 may issue a warning to the operator via the sound output device 45. The warning is, for example, a sound that is significantly louder than the intermittent sound. The controller 30 may present the operator with the magnitude of the distance between the claw tip of the bucket 6 and the buried object by using a bar gauge.

The controller 30 may autonomously control the movement of the excavation attachment AT such that the predetermined portion of the excavation attachment AT does not enter the approach restriction area. Specifically, for example, when the controller 30 determines that the claw tip of the bucket 6 will enter the approach restriction area if the operator manually performs the arm closing operation as it is, the controller 30 may disable that arm closing operation. Alternatively, the controller 30 may automatically extend the boom cylinder 7 to raise the boom 4 such that the claw tip of the bucket 6 does not enter the approach restriction area.

The controller 30 may simultaneously display the buried object figure G13A and the buried object figure G13B. This is because the degree of deviation of the buried object from the initial position or the deformation of the buried object is presented to the operator in an easily understandable manner. The operator can estimate the deviation of another buried object buried nearby by viewing such an image. Further, the operator can predict the deviation of the buried object which may occur in the future.

Further, the controller 30 may display auxiliary information represented by a dash-dot line, a double-headed arrow, and the like. The auxiliary information may include, for example, a sub-window for displaying details of the buried object data, a balloon image for displaying information about the object to be excavated taken into the bucket 6, and the like. The sub-window may display, for example, the time when the buried object is buried, the type of the buried object, the material of the buried object, the size of the buried object, or the like. The balloon image may display, for example, the weight of the earth taken into the bucket 6.

The auxiliary information may include a vertical distance between the approach restriction area and the ground above the approach restriction area, a vertical distance between the buried object and the ground above the buried object, a vertical distance between the claw tip of the bucket 6 and the buried object, a horizontal distance between the buried object and the ground (wall surface) on the excavator 100 side, a horizontal distance between the claw tip of the bucket 6 and the buried object, a bucket back surface angle, or the like. The bucket back surface angle is an angle formed between a virtual plane including the back surface of the bucket 6 and a virtual horizontal plane.

The auxiliary information may include information about a horizontal deviation or a vertical deviation between the position of the buried object based on the construction information and the position of the buried object based on the detection result of the buried object detection unit 32.

The controller 30 may project an output image as illustrated in FIG. 7 onto the ground using a projector attached to the upper slewing body 3. In this case, the bucket figure G11 and the arm figure G12 are preferably not displayed, and the image is projected such that the actual position of the buried object matches the display position of the buried object figure G13.

Next, another configuration example of the excavation control system that can be mounted on the excavator 100 of FIG. 1 will be described with reference to FIG. 8. FIG. 8 is a diagram illustrating another configuration example of an excavation control system. The excavation control system of FIG. 8 differs from the excavation control system of FIG. 4, which is configured to detect a buried object based on excavation reaction force, mainly in that the buried object is detected using an image acquired by the front camera 70F that is one of the object detection devices 70.

In the excavation control system of FIG. 8, the front camera 70F also functions as a detection device which is a device that detects information about the ground raised by excavation. The front camera 70F may be an imaging device attached to the excavation attachment AT, such as an imaging device attached to the side surface or the inward surface e of the arm 5.

The buried object detection unit 32 is configured to be able to detect a buried object based on information about the ground raised by excavation. In the example illustrated in FIG. 8, the buried object detection unit 32 is configured to be able to estimate the presence or absence of a buried object based on an image acquired by the front camera 70F.

Here, an example of a process in which the buried object detection unit 32 estimates the presence or absence of a buried object will be described with reference to FIG. 9. FIG. 9 is a view illustrating a cross section of the ground in which the water pipe U1 as a buried object is buried. The position represented by a broken line circle PT1 in FIG. 9 indicates an excavation start position, the position represented by a broken line circle PT2 in FIG. 9 indicates a bucket claw tip position, and the position represented by a broken line circle PT3 in FIG. 9 indicates an earth pile end position. In FIG. 9, for the purpose of clarity, a rough dot pattern is applied to a cross section of the ground to be excavated, and a fine dot pattern is applied to a cross section of an earth pile formed by the raised ground.

The bucket claw tip position means a position of the claw tip of the bucket 6. The buried object detection unit 32 can calculate the bucket claw tip position based on the output of the attitude detection device M1. The buried object detection unit 32 may calculate the bucket claw tip position based on the image acquired by the front camera 70F.

The excavation start position means a position at which excavation is started. In the illustrated example, the excavation start position is a bucket claw tip position when the claw tip of the bucket 6 comes into contact with the ground to be excavated. The buried object detection unit 32 can determine whether or not the claw tip of the bucket 6 has come into contact with the ground based on the output of the excavation pressure sensor S1. The buried object detection unit 32 may determine whether the claw tip of the bucket 6 has come into contact with the ground based on the image acquired by the front camera 70F. The buried object detection unit 32 may calculate the excavation start position based on the image acquired by the front camera 70F.

The earth pile end position, indicated by the broken line circle PT3 in FIG. 9, means a position of the edge of the ground raised by excavation on the side closer to the cabin 10 (upper slewing body 3). In the illustrated example, the buried object detection unit 32 can calculate the earth pile end position based on the image acquired by the front camera 70F. In this case, the buried object detection unit 32 may determine a range of the ground (a range of the earth pile) raised by excavation, for example, based on an image of the ground before the excavation and an image of the ground during the excavation. For example, the buried object detection unit 32 may set a range in which a change in an image occurs due to excavation as the range of the earth pile. Alternatively, the buried object detection unit 32 may calculate distances between the front camera 70F and respective points on the ground based on the image acquired by the front camera 70F. The buried object detection unit 32 may set a portion raised by a predetermined height or more by excavation as the range of the earth pile.

In the illustrated example, the buried object detection unit 32 repeatedly calculates the bucket claw tip position and the earth pile end position at the predetermined calculation cycle. The buried object detection unit 32 repeatedly calculates the distances DS1, DS2, and DS3 at the predetermined calculation cycle based on the calculated excavation start position, bucket claw tip position, and earth pile end position. The buried object detection unit 32 may omit the calculation of a distance DS3.

A distance DS1 is a distance (horizontal distance) between the excavation start position and the bucket claw tip position in the front-rear direction, and corresponds to an “excavation length.” The front-rear direction is a direction parallel to the front-rear axis of the excavator 100. The front-rear axis of the excavator 100 is an axis perpendicular to the slewing axis of the excavator 100 and perpendicular to the right-left axis of the excavator 100, and extends so as to bisect the excavation attachment AT in a top view. The left-right axis of the excavator 100 is an axis perpendicular to the slewing axis of the excavator 100 and perpendicular to the front-rear axis of the excavator 100. A distance DS2 is a distance (horizontal distance) between the bucket claw tip position and the earth pile end position in the front-rear direction. The distance DS3 is a distance (vertical distance) between the excavation start position and the bucket claw tip position in the up-down direction, and corresponds to an “excavation depth.” The up-down direction is a direction parallel to the slewing axis of the excavator 100. The claw tip position that determines the distances DS1, DS2, and DS3 may be replaced with a monitoring position such as a position of the coupling pin that couples the arm 5 and the bucket 6 or a position of the tip of the rod of the bucket cylinder 9. In this case, the buried object detection unit 32 may calculate the monitoring position based on the image acquired by the front camera 70F. This is because the monitoring position is less likely to be buried in the ground than the bucket claw tip position.

The buried object detection unit 32 estimates the presence or absence of a buried object based on a comparison result between the distance DS2 and a predetermined threshold. In detail, the buried object detection unit 32 estimates that the buried object is present when the distance DS2 falls below the threshold. This is because, when the buried object is present in the traveling direction of the bucket 6, the ground is prevented from being raised by the buried object, and the edge (the edge including the earth pile end position represented by the broken line circle PT3 in FIG. 9) of the ground raised by excavation on the side closer to the cabin 10 is formed at a position closer to the bucket 6 than when the buried object is not present.

The nonvolatile storage device of the controller 30 stores in advance a correspondence between the distances DS1 and the distance thresholds as a reference table. The buried object detection unit 32 can repeatedly derive a distance threshold corresponding to the calculated current distance DS1 at the predetermined calculation cycle with reference to the reference table. In the illustrated example, the distance threshold is set to increase as the distance DS1 increases, that is, the distance threshold is set to increase as the bucket claw tip position moves away from the excavation start position. Note that the nonvolatile storage device of the controller 30 may store in advance a correspondence between the distances DS1, the distances DS3, and the distance thresholds as a reference table. In this case, the buried object detection unit 32 can repeatedly derive the distance threshold corresponding to the calculated current distance DS1 (excavation length) and the distance DS3 (excavation depth) at the predetermined calculation cycle. Further, the nonvolatile storage device of the controller 30 may store a plurality of reference tables in a selectable manner in consideration of differences in the shape of the bucket 6, the characteristics (viscosity and the like) of the earth, the type of the earth, and the like. In this case, information about the shape of the bucket 6, the characteristics (viscosity and the like) of the earth, the type of the earth, and the like may be input to the controller 30 before the excavation is performed.

The buried object detection unit 32 estimates the presence or absence of a buried object by comparing the current distance DS2 with the distance thresholds derived by referring to the reference table. In the illustrated example, the buried object detection unit 32 repeatedly estimates the presence or absence of a buried object at an estimation cycle, which is the same as the predetermined calculation cycle, from the time point when the claw tip of the bucket 6 comes into contact with the ground to the time point when the claw tip of the bucket 6 is separated from the ground. The buried object detection unit 32 may determine that the claw tip of the bucket 6 is separated from the ground when the distance DS3 becomes zero, for example.

The buried object detection unit 32 that is a part of the excavation control system of FIG. 8 may output a control command to the control valve E1, may output a control command to the display device 40, and may output a control command to the sound output device 45 when it is estimated that a buried object is present, as in the case of the excavation control system of FIG. 4.

The controller 30 that is a part of the excavation control system of FIG. 8 may be configured to activate the buried object detection function in response to an activation command from the buried object detection mode switch 76, as in the case of the excavation control system of FIG. 4. In the example illustrated in FIG. 8, when the buried object detection function is activated, the buried object detection unit 32 can estimate the presence or absence of a buried object based on the image acquired by the front camera 70F. On the other hand, the controller 30 may be configured to deactivate the buried object detection function in response to a deactivation command from the buried object detection mode switch 76.

In the example illustrated in FIG. 8, the buried object detection function may be configured to be executed even when the operation mode of the excavator 100 is any of the M (manual) mode and the SA (semi-automatic) mode, as in the case of the excavation control system of FIG. 4. However, the buried object detection function may be configured to be executed only when the SA (semi-automatic) mode is selected.

When the SA (semi-automatic) mode is selected, one excavation operation for finding a buried object (a series of operations from the insertion of the claw tip of the bucket 6 into the ground to the separation of the bucket 6 from the ground) may be automatically executed when the buried object detection mode switch 76 is operated, as in the case of the excavation control system of FIG. 4. That is, each excavation operation may be automatically executed every time the buried object detection mode switch 76 is operated.

Further, the controller 30 that is a part of the excavation control system of FIG. 8 may include the excavation reaction force calculation unit 31 as in the case of the excavation control system of FIG. 4. In this case, the buried object detection unit 32 may estimate that the buried object is present when the value of the excavation reaction force F calculated by the excavation reaction force calculation unit 31 exceeds a predetermined excavation reaction force threshold Ft and the distance DS2 falls below a distance threshold.

Alternatively, the buried object detection unit 32 may start deriving the distances DS1, DS2, and the distance threshold when the value of the excavation reaction force F calculated by the excavation reaction force calculation unit 31 exceeds the predetermined excavation reaction force threshold Ft. In addition, the buried object detection unit 32 may estimate that the buried object is present when the distance DS2 falls below the distance threshold. However, the buried object detection unit 32 may start the calculation of the excavation reaction force F when the distance DS2 falls below the distance threshold. In addition, the buried object detection unit 32 may estimate that the buried object is present when the value of the excavation reaction force F exceeds the predetermined excavation reaction force threshold Ft. This is to reduce the calculation load of the controller 30.

Next, an example of a process in which the buried object detection unit 32 estimates an arrangement of a buried object will be described with reference to FIG. 10. FIG. 10 includes top views of the excavation attachment AT during an excavation operation. A rectangle indicated by a broken line in FIG. 10 indicates an arrangement of a buried object U which is buried in the ground and is not visible in practice. In FIG. 10, the buried object U is a rod-shaped member extending horizontally. In FIG. 10, for the purpose of clarity, a rough dot pattern is applied to the ground to be excavated, a fine dot pattern is applied to the earth pile formed by the raised ground, and a cross pattern is applied to a hole formed by the excavation. Specifically, the left drawing of FIG. 10 illustrates the buried object U (a buried object U11) buried to extend to the left and right (perpendicular to the front-rear direction) on the side closer to the bucket 6 when viewed from the operator's seat in the cabin 10. The middle drawing of FIG. 10 illustrates the buried object U (a buried object U12) buried such that a left end of the buried object is closer to the cabin 10 than a right end of the buried object (obliquely with respect to the front-rear direction). The right drawing of FIG. 10 illustrates the buried object U (a buried object U13) buried such that the right end of the buried object is closer to the cabin 10 than the left end of the buried object (obliquely with respect to the front-rear direction).

The buried object detection unit 32 estimates the arrangement of the buried object U based on information about the ground raised by excavation. In the illustrated example, the buried object detection unit 32 repeatedly calculates a left end position and a right end position at the predetermined calculation cycle. The left end position means a position of an edge on the front left side (a position closest to the cabin 10) of the ground raised by excavation, and the right end position means a position of an edge on the front right side (a position closest to the cabin 10) of the ground raised by excavation. The term “left” means to the left of the center plane CP of the excavation attachment AT, and the term “right” means to the right of the center plane CP of the excavation attachment AT. The center plane CP of the excavation attachment AT is a plane that includes the front-rear axis of the excavator 100 and the slewing axis of the excavator 100. In the illustrated example, the buried object detection unit 32 can calculate the left end position and the right end position based on the image acquired by the front camera 70F. The buried object detection unit 32 repeatedly calculates the distance DS2 (a left-side distance DS2L and a right-side distance DS2R) at the predetermined calculation cycle based on the calculated left end position and right end position.

The left-side distance DS2L is a distance between the bucket claw tip position and the left end position in the front-rear direction. The right-side distance DS2R is a distance between the bucket claw tip position and the right end position in the front-rear direction.

Then, when the buried object detection unit 32 estimates that the buried object U is present based on the excavation reaction force and the like, the buried object detection unit 32 estimates the arrangement of the buried object U based on the comparison result between the left-side distance DS2L and the right-side distance DS2R. The buried object detection unit 32 may simultaneously perform determination of the presence or absence of the buried object U and estimation of the arrangement of the buried object U, may estimate the arrangement of the buried object U without performing the determination of the presence or absence of the buried object U, or may perform the determination of the presence or absence of the buried object U after the estimation of the arrangement of the buried object U.

For example, as illustrated in the left drawing of FIG. 10, when the difference between the left-side distance DS2L and the right-side distance DS2R falls below a first threshold, the buried object detection unit 32 may estimate that the buried object U11 is buried so as to extend along the left-right direction. This is because, when the buried object U is buried along the left-right direction, the shape of the earth pile on the left side of the center plane CP and the shape of the earth pile on the right side of the center plane CP are likely to be substantially the same. The left-right direction is a direction parallel to the left-right axis of the excavator 100.

Alternatively, as illustrated in the middle drawing of FIG. 10, when the left-side distance DS2L is greater than the right-side distance DS2R and the difference between the left-side distance DS2L and the right-side distance DS2R is equal to or greater than a second threshold, the buried object detection unit 32 may estimate that the buried object U12 is buried such that the left end is closer to the cabin 10 than the right end (obliquely with respect to the front-rear direction). This is because, when the buried object U12 is buried as illustrated in the middle drawing of FIG. 10, the earth pile on the left side of the center plane CP is likely to spread in the front-rear direction, and the earth pile on the right side of the center plane CP is unlikely to spread in the front-rear direction.

Alternatively, as illustrated in the right drawing of FIG. 10, when the right-side distance DS2R is greater than the left-side distance DS2L and the difference between the left-side distance DS2L and the right-side distance DS2R is equal to or greater than a third threshold, the buried object detection unit 32 may estimate that the buried object U13 is buried such that the right end is closer to the cabin 10 than the left end (obliquely with respect to the front-rear direction). This is because, when the buried object U13 is buried as illustrated in the right drawing of FIG. 10, the earth pile on the left side of the center plane CP is less likely to spread in the front-rear direction, and the earth pile on the right side of the center plane CP is more likely to spread in the front-rear direction. The first threshold, the second threshold, and the third threshold may be the same value or may be different values.

Alternatively, the buried object detection unit 32 may repeatedly calculate an earth pile left end position and an earth pile right end position at the predetermined calculation cycle. The earth pile left end position means a position of a left edge of the ground raised by excavation, and the earth pile right end position means a position of a right edge of the ground raised by excavation. In the illustrated example, the buried object detection unit 32 can calculate the earth pile left end position and the earth pile right end position based on the image acquired by the front camera 70F. The buried object detection unit 32 repeatedly calculates a left-side width WDL and a right-side width WDR at the predetermined calculation cycle based on the calculated earth pile left end position and earth pile right end position.

The left-side width WDL is a distance between the center plane CP of the excavation attachment AT and the earth pile left end position in the left-right direction. The right-side width WDR is a distance between the center plane CP of the excavation attachment AT and the earth pile right end position in the right-left direction.

Then, when the buried object detection unit 32 estimates that the buried object U is present based on the excavation reaction force or the like, the buried object detection unit 32 may estimate the arrangement of the buried object U based on the comparison result between the left-side width WDL and the right-side width WDR. The buried object detection unit 32 may simultaneously perform determination of the presence or absence of the buried object U and estimation of the arrangement of the buried object U, may estimate the arrangement of the buried object U without performing the determination of the presence or absence of the buried object U, or may perform the determination of the presence or absence of the buried object U after the estimation of the arrangement of the buried object U.

For example, as illustrated in the left drawing of FIG. 10, when the difference between the left-side width WDL and the right-side width WDR falls below the first threshold, the buried object detection unit 32 may estimate that the buried object U11 is buried so as to extend along the left-right direction. This is because, when the buried object U is buried along the left-right direction, the shape of the earth pile on the left side of the center plane CP and the shape of the earth pile on the right side of the center plane CP are likely to be substantially the same.

Alternatively, as illustrated in the middle drawing of FIG. 10, when the left-side width WDL is greater than the right-side width WDR and the difference between the left-side width WDL and the right-side width WDR is equal to or greater than the second threshold, the buried object detection unit 32 may estimate that the buried object U12 is buried such that the left end is closer to the cabin 10 than the right end (obliquely with respect to the front-rear direction). This is because, when the buried object U12 is buried as illustrated in the middle drawing of FIG. 10, the earth pile on the left side of the center plane CP is likely to spread to the left side, and the earth pile on the right side of the center plane CP is unlikely to spread to the right side.

Alternatively, as illustrated in the right drawing of FIG. 10, when the right-side width WDR is greater than the left-side width WDL and the difference between the left-side width WDL and the right-side width WDR is equal to or greater than the third threshold, the buried object detection unit 32 may estimate that the buried object U13 is buried such that the right end is closer to the cabin 10 than the left end (obliquely with respect to the front-rear direction) This is because, when the buried object U13 is buried as illustrated in the right drawing of FIG. 10, the earth pile on the left side of the center plane CP is less likely to spread to the left side, and the earth pile on the right side of the center plane CP is more likely to spread to the right side. The first threshold, the second threshold, and the third threshold may be the same value or may be different values.

The buried object detection unit 32 may estimate the arrangement of the buried object U based on the comparison result between the left-side distance DS2L and the right-side distance DS2R and the comparison result between the left-side width WDL and the right-side width WDR.

The buried object detection unit 32 may estimate the arrangement of the buried object U based on the information about the excavation reaction force, or may estimate the arrangement of the buried object U based on the information about the ground raised by excavation and the information about the excavation reaction force. For example, the buried object detection unit 32 may estimate the arrangement of the buried object U based on the excavation reaction force acting in the slewing direction calculated by the excavation reaction force calculation unit 31.

Specifically, the buried object detection unit 32 may estimate that the buried object U12 is buried such that the left end is closer to the cabin 10 than the right end (obliquely with respect to the front-rear direction) when the excavation reaction force acting in the left slewing direction is equal to or greater than a left slewing threshold. This is because, when the buried object U12 is buried as illustrated in the middle drawing of FIG. 10, the excavation reaction force acting on the right half of the bucket 6 becomes greater than the excavation reaction force acting on the left half of the bucket 6, and a rotational moment in a direction indicated by an arrow AR1 acts on the bucket 6. In the illustrated example, the excavation reaction force acting in the left slewing direction is the left slewing pressure (P17) when the left slewing pressure (P17) is greater than the right slewing pressure (P18).

Similarly, the buried object detection unit 32 may estimate that the buried object U13 is buried such that the right end is closer to the cabin 10 than the left end (obliquely with respect to the front-rear direction) when the excavation reaction force acting in the right slewing direction is equal to or greater than a right slewing threshold. This is because, when the buried object U13 is buried as illustrated in the middle drawing of FIG. 10, the excavation reaction force acting on the left half of the bucket 6 becomes greater than the excavation reaction force acting on the right half of the bucket 6, and a rotational moment in a direction indicated by an arrow AR2 acts on the bucket 6. In the illustrated example, the excavation reaction force acting in the right slewing direction is the right slewing pressure (P18) when the right slewing pressure (P18) is greater than the left slewing pressure (P17). The left slewing threshold and the right slewing threshold may be the same value or may be different values.

Further, FIG. 10 illustrates an example of a case where the buried object U is present in the traveling direction of the left half of the bucket 6 and the buried object U is also present in the traveling direction of the right half of the bucket 6. However, the buried object detection unit 32 may estimate that the buried object U is buried by the same method such that the buried object U is present only in the traveling direction of the left half of the bucket 6 and the buried object U is not present in the traveling direction of the right half of the bucket 6. Further, the buried object detection unit 32 may estimate that the buried object U is buried by the same method such that the buried object U is present only in the traveling direction of the right half of the bucket 6 and the buried object U is not present in the traveling direction of the left half of the bucket 6.

Next, a control system SYS of the excavator will be described with reference to FIG. 11. FIG. 11 is a diagram illustrating a configuration example of the control system SYS of the excavator. The information acquired by the excavator 100 may be shared with a manager, an operator of another excavator, and the like through the control system SYS of the excavator as illustrated in FIG. 11.

The control system SYS is a system that controls the excavator 100. In the illustrated example, the control system SYS is mainly configured by the excavator 100, a support device 200, and a management device 300. Each of the excavator 100, the support device 200, and the management device 300 includes a communication device, and is directly or indirectly connected to each other via a mobile phone communication network, a satellite communication network, a near-field communication network, or the like. The number of each of the excavators 100, the support devices 200, and the management devices 300 that form the control system SYS may be one or more. In the example of FIG. 11, the control system SYS includes one excavator 100, one support device 200, and one management device 300.

The support device 200 is typically a portable terminal device, and is, for example, a computer, such as a laptop PC, a tablet PC, or a smartphone carried by a worker or the like at a construction site. The support device 200 may be a computer carried by an operator of the excavator 100. However, the support device 200 may be a fixed terminal device.

The management device 300 is typically a fixed terminal device, and is, for example, a server computer installed in a management center or the like outside the construction site. The management device 300 may be a portable computer (for example, a portable terminal device, such as a laptop PC, a tablet PC, or a smartphone).

At least one of the support device 200 and the management device 300 may include a monitor and an operation device for remote control. In this case, the excavator 100 and at least one of the support device 200 and the management device 300 constitute a remote control system of the excavator. The operator can operate the excavator 100 while using the operation device for remote control. The operation device for remote control is connected to the controller 30 through a communication network, such as a mobile phone communication network, a satellite communication network, or a near-field communication network. The controller 30 may be included in the support device 200 or may be included in the management device 300. A11 or some of the functions executed by the controller 30 may be executed by the support device 200 or the management device 300. The excavator 100 may be an unmanned excavator. In this case, the excavator 100 autonomously operates independently of the operation performed on the operation device 26 (including an operation device for remote control).

In the example illustrated in FIG. 11, the buried object detection mode switch 76 may be provided in the support device 200 or the management device 300. The buried object detection function may be executed by the support device 200 or the management device 300.

As described above, the excavator 100 according to the embodiment of the present disclosure includes the lower traveling body 1, the upper slewing body 3 mounted on the lower traveling body 1, the controller 30 mounted on the upper slewing body 3, the excavation attachment AT attached to the upper slewing body 3, and the detection device that detects information about at least one of the excavation reaction force during excavation performed by the excavation attachment AT or the ground raised by excavation. The detection device that detects information about the excavation reaction force is, for example, an excavation pressure sensor S1. The information about the excavation reaction force is, for example, an analog value, a digital value, or the like representing a physical quantity used for calculation of the excavation reaction force. The detection device that detects information about the excavation reaction force may include the attitude detection device M1. The detection device that detects information about the raised ground is, for example, the object detection device 70. The information about the raised ground is, for example, a boundary line between the raised ground and the non-raised ground, a height of the raised portion, a shape of the raised portion, a volume of the raised portion, a surface area of the raised portion, or the like. The object detection device 70 is, for example, an imaging device, such as a monocular camera or a LiDAR. The detection device that detects information about the raised ground may include at least one of the attitude detection device M1 and the excavation pressure sensor S1. The excavator 100 is configured to estimate the presence or absence of the buried object based on the information detected by the detection device.

With this configuration, the excavator 100 can estimate the presence or absence of the buried object during the excavation work, and thus can prevent the buried object from being destroyed due to contact between the excavation attachment AT and the buried object during the excavation work.

The excavator 100 may include the controller 30 that controls the movement of the excavation attachment AT. In this case, the controller 30 may be configured to control the movement of the excavation attachment AT so as to avoid contact between the buried object and the excavation attachment AT when it is estimated that the buried object is present.

The controller 30 may be configured to calculate an excavation reaction force during excavation by the excavation attachment AT. In this case, the detection device may be configured to detect information about the ground raised by excavation. The controller 30 may be configured to estimate the presence or absence of the buried object based on at least one of the excavation reaction force and the information detected by the detection device.

With this configuration, even when the operator of the excavator 100 performs a manual operation of bringing the excavation attachment AT close to the buried object, the controller 30 can move the excavation attachment AT away from the buried object or stops the movement of the excavation attachment AT. Therefore, the controller 30 can more reliably prevent the buried object from being destroyed due to contact between the excavation attachment AT and the buried object during the excavation work.

The excavator 100 may be configured to notify an outside of the presence of the buried object when the presence of the buried object is estimated. For example, as illustrated in FIG. 4, the buried object detection unit 32 of the controller 30 may output a control command to at least one of the display device 40 and the sound output device 45 when it is estimated that the buried object is present, and visually or audibly notify the operator of the excavator 100 that the buried object is present near the claw tip of the bucket 6.

With this configuration, the controller 30 can more reliably prevent the buried object from being destroyed due to contact between the excavation attachment AT and the buried object during the excavation work.

The excavator 100 may be configured to estimate the presence or absence of a buried object based on at least one of the excavation reaction force calculated when the excavation attachment AT is moved along a predetermined trajectory to perform the excavation and the information about the ground raised by excavation. For example, the buried object detection unit 32 of the controller 30 may be configured to estimate the presence or absence of a buried object based on a comparison result between the excavation reaction force calculated by the excavation reaction force calculation unit 31 and the excavation reaction force threshold when the claw tip of the bucket 6 moves along the target trajectory TP. Alternatively, the buried object detection unit 32 may be configured to estimate the presence or absence of the buried object based on the comparison result between the distance DS2 calculated when the claw tip of the bucket 6 moves along the target trajectory TP and the distance threshold. Alternatively, the buried object detection unit 32 may be configured to estimate the presence or absence of a buried object based on the comparison result between the excavation reaction force calculated when the claw tip of the bucket 6 moves along the target trajectory TP and the excavation reaction force threshold, and the comparison result between the distance DS2 calculated when the claw tip of the bucket 6 moves along the target trajectory TP and the distance threshold.

The excavator 100 may be configured to estimate the presence or absence of a buried object based on at least one of an excavation reaction force generated when the bucket 6 that is a part of the excavation attachment AT is moved in a direction approaching a body of the upper slewing body 3 to perform excavation and information about the ground raised by excavation. For example, as illustrated in FIG. 5, the buried object detection unit 32 of the controller 30 may be configured to estimate that a buried object is present when the excavation reaction force F calculated when the claw tip of the bucket 6 moves toward the body of the upper slewing body 3 along the target trajectory TP exceeds the predetermined excavation reaction force threshold Ft (see FIG. 6). Alternatively, as illustrated in FIG. 9, the buried object detection unit 32 may be configured to estimate that a buried object is present when the distance DS2 calculated when the claw tip of the bucket 6 moves toward the body of the upper slewing body 3 falls below the distance threshold. Alternatively, the buried object detection unit 32 may be configured to estimate that a buried object is present when the excavation reaction force F calculated when the claw tip of the bucket 6 moves toward the body of the upper slewing body 3 along the target trajectory TP exceeds the excavation reaction force threshold Ft and the distance DS2 calculated when the claw tip of the bucket 6 moves toward the body of the upper slewing body 3 falls below the distance threshold.

With this configuration, the excavator 100 can accurately estimate the presence or absence of the buried object, and thus can more reliably prevent the buried object from being destroyed due to contact between the excavation attachment AT and the buried object during the excavation work.

In the above-described embodiment, the buried object detection unit 32 is configured to estimate the presence or absence of a buried object based on the excavation reaction force calculated by the excavation reaction force calculation unit 31 when the claw tip of the bucket 6 moves along the target trajectory TP. However, the buried object detection unit 32 may be configured to estimate the presence or absence of a buried object based on the excavation reaction force calculated by the excavation reaction force calculation unit 31 when the claw tip of the bucket 6 moves independently of a predetermined trajectory, such as the target trajectory TP.

As illustrated in FIG. 1, an excavator 100 according to the embodiment of the present disclosure includes a lower traveling body 1, an upper slewing body 3 mounted on the lower traveling body 1, an excavation attachment AT attached to the upper slewing body 3, and a detection device that detects information about at least one of an excavation reaction force during excavation by the excavation attachment AT and a ground raised by excavation. The detection device that detects information about the excavation reaction force is, for example, the excavation pressure sensor S1. The detection device that detects information about the excavation reaction force may include the attitude detection device M1. The detection device that detects information about the raised ground is, for example, the object detection device 70. The object detection device 70 is, for example, an imaging device, such as a monocular camera or a LiDAR. The excavator 100 is configured to estimate the arrangement of the buried object U based on the information detected by the detection device.

With this configuration, the excavator 100 can estimate the arrangement of the buried object U during the excavation work, and thus can prevent the buried object U from being destroyed due to contact between the excavation attachment AT and the buried object U during the excavation work.

Further, as illustrated in FIG. 10, the information about the ground raised by excavation may include information about a range of a portion of the earth pile formed by the ground raised by excavation, the portion being located on the left side of the center plane CP of the excavation attachment AT extending in the front-rear direction, and information about a range of a portion of the earth pile formed by the ground raised by excavation, the portion being located on the right side of the center plane CP.

The information about the excavation reaction force during excavation performed by the excavation attachment AT may include information about excavation reaction force acting in the slewing direction.

With these configurations, the excavator 100 can more accurately estimate the arrangement of the buried object U buried in the ground. For example, the excavator 100 can estimate whether or not the buried object U is buried obliquely with respect to the front-rear direction. Alternatively, the excavator 100 can estimate that the distance between the left end of the bucket 6 and the buried object U in the front-rear direction is greater or smaller than the distance between the right end of the bucket 6 and the buried object U in the front-rear direction. Alternatively, the excavator 100 can estimate that the buried object U is present in the traveling direction of the left half of the bucket 6, and the buried object is not present in the traveling direction of the right half of the bucket 6.

Although the preferred embodiments of the present disclosure have been described in detail, the present disclosure is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present disclosure.

Claims

1. A control device for an excavator, the control device comprising: circuitry configured to control the excavator; anda sensor configured to detect information about a ground raised by excavation,wherein the circuitry estimates presence or absence of a buried object based on at least one of an excavation reaction force calculated during excavation by an excavation attachment of the excavator or information detected by the sensor.

2. The control device according to claim 1, wherein the circuitry controls a movement of the excavation attachment so as to avoid contact between the buried object and the excavation attachment when the presence of the buried object is estimated.

3. The control device according to claim 1, wherein the circuitry notifies an outside of the presence of the buried object when the presence of the buried object is estimated.

4. The control device according to claim 1, wherein the circuitry estimates the presence or absence of the buried object based on at least one of an excavation reaction force calculated when the excavation attachment is moved along a predetermined trajectory to perform excavation or the information about the ground raised by excavation.

5. The control device according to claim 1, wherein the circuitry estimates the presence or absence of the buried object based on at least one of an excavation reaction force generated when a bucket that is a part of the excavation attachment is moved in a direction approaching a body of the excavator to perform excavation or the information about the ground raised by excavation.

6. A control device for an excavator, the control device comprising: circuitry configured to control the excavator; anda sensor configured to detect information about a ground raised by excavation, wherein the circuitry estimates an arrangement of a buried object based on at least one of an excavation reaction force during excavation by an excavation attachment of the excavator or information detected by the sensor.

7. The control device according to claim 6, wherein the information about the ground raised by excavation includes information about a range of a portion of an earth pile formed by the ground raised by excavation, the portion being located on a left side of a center plane of the excavation attachment extending in a front-rear direction, and information about a range of another portion of the earth pile formed by the ground raised by excavation, the another portion being located on a right side of the center plane.

8. The control device according to claim 6, wherein the excavation reaction force during excavation by the excavation attachment includes an excavation reaction force acting in a slewing direction.

9. An excavator, comprising: the control device according to claim 1;a lower traveling body;an upper slewing body mounted on the lower traveling body; andan excavation attachment attached to the upper slewing body.