CONTROL DEVICE FOR EXCAVATOR

Abstract

A control device for an excavator is provided, wherein the excavator includes a lower traveling body; an upper slewing body slewably mounted on the lower traveling body; and an attachment attached to the upper slewing body, the attachment including a boom, an arm, and an end attachment. The control device includes circuitry configured to operate the arm in response to a command value so as to move a predetermined work part of the end attachment while aligning the predetermined work part with a target surface, and to operate at least one of the boom or the end attachment in accordance with the operation of the arm, wherein the circuitry controls the operation of at least one of the arm or the boom such that a moving speed of a control target along the target surface becomes a predetermined speed, the control target being a predetermined part of the attachment.

Description

BACKGROUND

1. Technical Field

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

2. Description of Related Art

Conventionally, an excavator capable of operating an attachment such that a claw tip of a bucket moves along a target construction surface is known.

SUMMARY

According to one embodiment of the present disclosure, a control device for an excavator is provided, the excavator including a lower traveling body; an upper slewing body slewably mounted on the lower traveling body; and an attachment attached to the upper slewing body, the attachment including a boom, an arm, and an end attachment. The control device includes:

• • circuitry configured to operate the arm in response to a command value so as to move a predetermined work part of the end attachment while aligning the predetermined work part with a target surface, and to operate at least one of the boom or the end attachment in accordance with the operation of the arm,
  • wherein the circuitry controls the operation of at least one of the arm or the boom such that a moving speed of a control target along the target surface becomes a predetermined speed, the control target being a predetermined part of the attachment, and
  • wherein in a case where the target surface includes a steep slope portion, and a gentle slope portion or a horizontal surface portion, and provided that an operation amount of an arm operation lever is same for both portions, the circuitry operates the arm such that a moving speed of the control target when moving the predetermined work part while aligning the predetermined work part with the gentle slope portion or the horizontal surface portion is same as a moving speed of the control target when moving the predetermined work part while aligning the predetermined work part with the steep slope portion.

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 top view of the excavator according to the embodiment of the present disclosure.

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

FIG. 4A is a diagram illustrating a portion of the hydraulic system related to an operation of an arm cylinder.

FIG. 4B is a diagram illustrating a portion of the hydraulic system related to an operation of a boom cylinder.

FIG. 4C is a diagram illustrating a portion of the hydraulic system related to an operation of a bucket cylinder.

FIG. 4D is a diagram illustrating a portion of the hydraulic system related to an operation of a slewing hydraulic motor.

FIG. 4E is a diagram illustrating a portion of the hydraulic system related to an operation of a left travel hydraulic motor.

FIG. 4F is a diagram illustrating a portion of the hydraulic system related to an operation of a right travel hydraulic motor.

FIG. 5 is a diagram illustrating a configuration example of a control system of the excavator.

FIG. 6A is a diagram illustrating a configuration example of a controller according to an embodiment.

FIG. 6B is a diagram illustrating a configuration example of the controller according to the embodiment.

FIG. 7 is a schematic diagram illustrating movement of an attachment.

FIG. 8 is a schematic diagram illustrating speed control of a work part performed by a controller according to another embodiment.

FIG. 9 is a diagram illustrating a change in a speed of a claw tip of a bucket corresponding to an operation by an operator in an excavator according to another embodiment.

FIG. 10A is a diagram illustrating a configuration example of the controller according to another embodiment.

FIG. 10B is a diagram illustrating a configuration example of the controller according to another embodiment.

FIG. 11 is a diagram illustrating a movement route of a claw tip of a bucket according to another embodiment.

DETAILED DESCRIPTION

The excavator described above is capable of moving a work part of the bucket at a constant speed along the target construction surface when an operation amount of an arm operation lever is maintained at a constant amount.

When the operation amount of the operation lever of the attachment is maintained at a constant amount, the movement of the attachment changes to align the work part of the attachment with the target surface when an angle or other change occurs on the target surface, and the moving speed of the work part may change significantly. The change in the moving speed of the work part may cause an operator of the excavator to feel discomfort.

Therefore, it is desirable to improve the operability of the attachment by performing control such that the moving speed of the work part does not change significantly.

The above-described control for device an excavator is capable of improving the operability of the attachment controlling the moving speed of the predetermined part to be the predetermined speed.

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the drawings, the same or corresponding components are denoted by the same reference numerals, and the description thereof may be omitted.

Embodiment

First, an excavator 100 as a digging machine according to an embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a side view of the excavator 100, and FIG. 2 is a top view of the excavator 100.

In the present embodiment, the lower traveling body 1 of the excavator 100 includes a crawler 1C as a driven body. The crawler 1C is driven by a traveling hydraulic motor 2M mounted on the lower traveling body 1. However, the traveling hydraulic motor 2M may be a traveling motor-generator as an electric actuator. In particular, the crawler 1C includes a left crawler 1CL and a right crawler 1CR. The left crawler 1CL is driven by a left traveling hydraulic motor 2ML, and the right crawler 1CR is driven by a right traveling hydraulic motor 2MR. The lower traveling body 1 is driven by the crawler 1C, and the lower traveling body 1 thus functions as a driven body.

An upper slewing body 3 is slewably mounted on the lower traveling body 1 via a slewing mechanism 2. The slewing mechanism 2 as a driven body is driven by a slewing hydraulic motor 2A mounted on the upper slewing body 3. However, the slewing hydraulic motor 2A may be a slewing motor-generator as an electric motor. The upper slewing body 3 is driven by the slewing mechanism 2, and the upper slewing body 3 thus functions as a driven body.

A boom 4 as a driven body is attached to the upper slewing body 3. An arm 5 as a driven body is attached to the tip of the boom 4, and a bucket 6 as a driven body and an end attachment is attached to the tip of the arm 5. The end attachment is a member attached to the distal end of the arm 5, and may be a breaker, a grapple, a lifting magnet, or the like. The boom 4, the arm 5, and the bucket 6 constitute an excavation attachment which is an example of the attachment AT. 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.

A boom angle sensor S1 is attached to the boom 4, an arm angle sensor S2 is attached to the arm 5, and a bucket angle sensor S3 is attached to the bucket 6.

The boom angle sensor S1 detects a rotation angle of the boom 4. In the present embodiment, the boom angle sensor S1 is an accelerometer, and can detect a boom angle which is a rotation angle of the boom 4 with respect to the upper slewing body 3. The boom angle is, for example, a minimum angle when the boom 4 is lowered to the lowest position, and increases as the boom 4 is raised.

The arm angle sensor S2 detects a rotation angle of the arm 5. In the present embodiment, the arm angle sensor S2 is an accelerometer, and can detect an arm angle which is a rotation angle of the arm 5 with respect to the boom 4. The arm angle is, for example, a minimum angle when the arm 5 is fully closed, and increases as the arm 5 is opened.

The bucket angle sensor S3 detects a rotation angle of the bucket 6. In the present embodiment, the bucket angle sensor S3 is an accelerometer, and can detect a bucket angle which is a rotation angle of the bucket 6 with respect to the arm 5. The bucket angle is, for example, a minimum angle when the bucket 6 is fully closed, and increases as the bucket 6 is opened.

The boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3 may be potentiometers using variable resistors, stroke sensors that detect the stroke amounts of the corresponding hydraulic cylinders, rotary encoders that detect the rotation angles around the coupling pins, gyro sensors, combinations of accelerometers and gyro sensors, or the like. The boom angle sensor S1 may be an operation detection unit (operation sensor 29LA described later) that detects an operation amount of a boom operation lever (described later). In this case, a controller 30 may calculate a boom angle based on an output of the operation sensor 29LA. The same applies to the arm angle sensor S2 and the bucket angle sensor S3.

The upper slewing body 3 is provided with a cabin 10 serving as an operator's compartment, 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. Further, an outdoor alarm device 45A, an object detection device 70, a positioning device 85, a body inclination sensor S4, a slewing angular velocity sensor S5, and the like are attached to the upper slewing body 3. An operation device 26, the controller 30, a display device 40, an indoor alarm device 45B, 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 a counterweight is mounted is referred to as a rear side.

The controller 30 is an example of a processing circuitry, and the controller 30 functions as a control device for controlling the excavator 100. In the present embodiment, the controller 30 is configured by a computer including a CPU, a RAM, an NVRAM, a ROM, and the like. The controller 30 reads a program corresponding to each function from the ROM, loads the program into the RAM, and causes the CPU to execute corresponding processing.

The display device 40 is configured to be able to display image information. In the illustrated example, the display device 40 is an organic EL display, and is configured to be able to present image information to the operator of the excavator 100.

The outdoor alarm device 45A is configured to be able to output a sound toward the outside of the cabin 10. In the illustrated example, the outdoor alarm device 45A is an outdoor speaker, and is configured to be able to output a sound for attracting attention of a worker who works around the excavator 100.

The indoor alarm device 45B is configured to output a sound toward the inside of the cabin 10. In the illustrated example, the indoor alarm device 45B is an indoor speaker, and is configured to output a sound for attracting attention of an operator who operates the excavator 100.

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, a 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 present embodiment, 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.

The positioning device 85 is configured to measure the position of the excavator 100. In the present embodiment, the positioning device 85 is a GNSS receiver in which an electronic compass is incorporated, calculates and outputs the latitude, the longitude, and the altitude of the excavator 100 based on the received GNSS signal, and calculates and outputs an orientation of the excavator 100.

The body inclination sensor S4 is configured to detect an inclination of the upper slewing body 3 with respect to a predetermined plane. In the present embodiment, the body inclination sensor S4 is an accelerometer that detects an inclination angle around the front-rear axis and an inclination angle around the left-right axis of the upper slewing body 3 with respect to a horizontal surface. The front-rear axis and the left-right axis of the upper slewing body 3 are, for example, orthogonal to each other and pass through the excavator center point which is one point on the slewing axis of the excavator 100.

The slewing angular velocity sensor S5 is configured to detect a slewing angular velocity of the upper slewing body 3. In the present embodiment, the slewing angular velocity sensor S5 is a gyro sensor. The slewing angular velocity sensor S5 may be a resolver, a rotary encoder, or the like. The slewing angular velocity sensor S5 may be configured to output at least one of the rotation speed and the slewing angle. In this case, at least one of the rotation speed and the slewing angle may be calculated from the slewing angular velocity.

Hereinafter, any combination of the boom angle sensor S1, the arm angle sensor S2, the bucket angle sensor S3, the body inclination sensor S4, and the slewing angular velocity sensor S5 is also collectively referred to as a posture sensor.

Next, a configuration example of a hydraulic system mounted on the excavator 100 will be described with reference to FIG. 3. FIG. 3 is a diagram illustrating a configuration example of a hydraulic system mounted on the excavator 100. FIG. 3 illustrates a mechanical power transmission system, a hydraulic fluid line, a pilot line, and an electrical control system by a double line, a solid line, a broken line, and a dotted line, respectively.

The hydraulic system of the excavator 100 mainly includes the engine 11, a pump regulator 13, a main pump 14, a pilot pump 15, a control valve unit 17, the operation device 26, a discharge pressure sensor 28, the operation sensor 29, the controller 30, a control valve 60, and the like.

In FIG. 3, the hydraulic system circulates the hydraulic fluid from the main pump 14 driven by the engine 11 to a hydraulic fluid tank via a center bypass pipe CB or a parallel pipe PC.

The engine 11 is a drive source of the excavator 100. In the present embodiment, the engine 11 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 configured to supply the hydraulic fluid to the control valve unit 17 via a hydraulic fluid line. In the present embodiment, the main pump 14 is a swash-plate-type variable displacement hydraulic pump.

The pump regulator 13 is configured to control a discharge amount of the main pump 14. In the present embodiment, the pump regulator 13 controls the discharge amount (push-off volume) of the main pump 14 by adjusting the swash plate tilting angle of the main pump 14 in response to a control command from the controller 30.

The pilot pump 15 is configured to supply a pilot oil to hydraulic control devices including the operation device 26 via a pilot line. In the present embodiment, the pilot pump 15 is a fixed displacement hydraulic pump. However, the pilot pump 15 may be omitted. In this case, the function of the pilot pump 15 may be implemented by the main pump 14. That is, the main pump 14 may have, in addition to a function of supplying the hydraulic fluid to the control valve unit 17, a function of supplying a hydraulic fluid as a pilot oil to the operation device 26, a solenoid valve 31 (see FIGS. 4A to 4F), and the like after reducing the pressure of the hydraulic fluid by a throttle or the like.

The control valve unit 17 is a hydraulic control device that controls a hydraulic system in the excavator 100. In the present embodiment, the control valve unit 17 includes control valves 171 to 176. The control valve 175 includes a control valve 175L and a control valve 175R, and the control valve 176 includes a control valve 176L and a control valve 176R. The control valve unit 17 can selectively supply a hydraulic fluid discharged by the main pump 14 to one or a plurality of hydraulic actuators through the control valves 171 to 176. The control valves 171 to 176 control a flow rate of the hydraulic fluid flowing from the main pump 14 to the hydraulic actuator and a flow rate of the hydraulic fluid flowing from the hydraulic actuator to the hydraulic fluid tank. The hydraulic actuators include the boom cylinder 7, an arm cylinder 8, the bucket cylinder 9, the left traveling hydraulic motor 2ML, the right traveling hydraulic motor 2MR, and the slewing hydraulic motor 2A.

The operation device 26 is a device used by an operator to operate an actuator. The actuator includes at least one of a hydraulic actuator and an electric actuator. In the present embodiment, the operation device 26 supplies a pilot oil discharged from the pilot pump 15 to a pilot port of a corresponding control valve in the control valve unit 17 via the pilot line. The pressure of the pilot oil (pilot pressure) supplied to each of the pilot ports is controlled by a lever or a pedal (not illustrated) of the operation device 26 corresponding to each of the hydraulic actuators. The pressure is a pressure corresponding to an operation direction and operation amount of the actuator.

The discharge pressure sensor 28 is configured to detect a discharge pressure of the main pump 14. In the present embodiment, the discharge pressure sensor 28 outputs a detected value to the controller 30.

The operation sensor 29 is configured to detect an operation content of the operation device 26 by the operator. In the present embodiment, the operation sensor 29 is an angle sensor that detects an operation direction and an operation amount of the lever or the pedal of the operation device 26 corresponding to each of the actuators in the form of an angle, and outputs the detected value to the controller 30. The operation content of the operation device 26 may be detected using a sensor other than the angle sensor.

The main pump 14 includes a left main pump 14L and a right main pump 14R. The left main pump 14L circulates a hydraulic fluid to the hydraulic fluid tank via the left center bypass pipeline CBL or the left parallel pipeline PCL, and the right main pump 14R circulates a hydraulic fluid to the hydraulic fluid tank via the right center bypass pipeline CBR or the right parallel pipeline PCR.

The left center bypass pipe CBL is a hydraulic fluid line passing through the control valves 171, 173, 175L, and 176L disposed in the control valve unit 17. The right center bypass pipe CBR is a hydraulic fluid line passing through the control valves 172, 174, 175R, and 176R disposed in the control valve unit 17.

The control valve 171 is a spool valve that switches a flow of the hydraulic fluid in order to supply a hydraulic fluid discharged by the left main pump 14L to the left traveling hydraulic motor 2ML and discharge the hydraulic fluid discharged by the left traveling hydraulic motor 2ML to the hydraulic fluid tank, and is also referred to as a “left traveling hydraulic motor control valve.”

The control valve 172 is a spool valve that switches a flow of the hydraulic fluid in order to supply a hydraulic fluid discharged by the right main pump 14R to the right traveling hydraulic motor 2MR and discharge the hydraulic fluid discharged by the right traveling hydraulic motor 2MR to the hydraulic fluid tank, and is also referred to as a “right traveling hydraulic motor control valve.”

The control valve 173 is a spool valve that switches a flow of the hydraulic fluid in order to supply a hydraulic fluid discharged from the left main pump 14L to the slewing hydraulic motor 2A and discharge the hydraulic fluid discharged from the slewing hydraulic motor 2A to the hydraulic fluid tank, and is also referred to as a “slewing hydraulic motor control valve.”

The control valve 174 is a spool valve that switches a flow of the hydraulic fluid in order to supply a hydraulic fluid discharged by the right main pump 14R to the bucket cylinder 9 and discharge the hydraulic fluid in the bucket cylinder 9 to the hydraulic fluid tank, and is also referred to as a “bucket cylinder control valve.”

The control valve 175L is a spool valve that switches a flow of the hydraulic fluid in order to supply a hydraulic fluid discharged by the left main pump 14L to the boom cylinder 7. The control valve 175R is a spool valve that switches a flow of the hydraulic fluid in order to supply a hydraulic fluid discharged by the right main pump 14R to the boom cylinder 7 and discharge the hydraulic fluid in the boom cylinder 7 to the hydraulic fluid tank. The control valve 175 is also referred to as a “boom cylinder control valve.”

The control valve 176L is a spool valve that switches a flow of the hydraulic fluid in order to supply a hydraulic fluid discharged by the left main pump 14L to the arm cylinder 8 and to discharge the hydraulic fluid in the arm cylinder 8 to the hydraulic fluid tank. The control valve 176R is a spool valve that switches a flow of a hydraulic fluid in order to supply the hydraulic fluid discharged by the right main pump 14R to the arm cylinder 8 and to discharge the hydraulic fluid in the arm cylinder 8 to the hydraulic fluid tank. The control valve 176 is also referred to as an “arm cylinder control valve.”

The left parallel pipeline PCL is a hydraulic fluid line parallel to the left center bypass pipeline CBL. The left parallel pipeline PCL can supply a hydraulic fluid to the control valve at the more downstream side when the flow of the hydraulic fluid passing through the left center bypass pipeline CBL is restricted or blocked by any of the control valves 171, 173, and 175L. The right parallel pipeline PCR is a hydraulic fluid line parallel to the right center bypass pipeline CBR. The right parallel pipeline PCR can supply a hydraulic fluid to the control valve at the more downstream side when the flow of the hydraulic fluid passing through the right center bypass pipeline CBR is restricted or blocked by any of the control valves 172, 174, and 175R.

The pump regulator 13 include a left pump regulator 13L and a right pump regulator 13R. The left pump regulator 13L controls a discharge amount (push-off volume) of the left main pump 14L by adjusting the swash plate tilt angle of the left main pump 14L according to the discharge pressure of the left main pump 14L. Specifically, the left pump regulator 13L, for example, adjusts the swash plate tilt angle of the left main pump 14L to decrease the discharge amount (push-off volume) in response to an increase in the discharge pressure of the left main pump 14L. The same applies to the right pump regulators 13R. This is to ensure that the absorbed power (absorbed horsepower) of the main pump 14, expressed as the product of the discharge pressure and the discharge amount, does not exceed the output power (output horsepower) of the engine 11.

The operation device 26 includes a left operation lever 26L, a right operation lever 26R, and a traveling lever 26D. The traveling lever 26D includes a left traveling lever 26DL and a right traveling lever 26DR.

The left operation lever 26L is used for a slewing operation and an operation of the arm 5. When the left operation lever 26L is operated in the front-rear direction, the left operation lever 26L introduces a control pressure corresponding to the operation amount into the pilot port of the control valve 176 by using the pilot oil discharged from the pilot pump 15. When the left operation lever 26L is operated in the left-right direction, the left operation lever 26L introduces a control pressure corresponding to the operation amount into the pilot port of the control valve 173 by using the pilot oil discharged from the pilot pump 15.

Specifically, when operated in the arm closing direction, the left operation lever 26L causes a pilot oil to be introduced into the right pilot port of the control valve 176L and also causes a pilot oil to be introduced into the left pilot port of the control valve 176R. When operated in the arm opening direction, the left operation lever 26L causes a pilot oil to be introduced into the left pilot port of the control valve 176L and also causes a pilot oil to be introduced into the right pilot port of the control valve 176R. When operated in the left slewing direction, the left operation lever 26L causes a pilot oil to be introduced into the left pilot port of the control valve 173, and when operated in the right slewing direction, the left operation lever 26L causes a pilot oil to be introduced into the right pilot port of the control valve 173. As described above, the left operation lever 26L functions as an “arm operation lever” when operated in the front-rear direction and functions as a “slewing operation lever” when operated in the left-right direction.

The right operation lever 26R is used for operation of the boom 4 and operation of the bucket 6. When operated in the front-rear direction, the right operation lever 26R introduces a control pressure corresponding to the operation amount into the pilot port of the control valve 175 by using the pilot oil discharged from the pilot pump 15. When operated in the left-right direction, the right operation lever 26R introduces a control pressure corresponding to the operation amount into the pilot port of the control valve 174 by using the pilot oil discharged from the pilot pump 15.

Specifically, when operated in the boom lowering direction, the right operation lever 26R causes a pilot oil to be introduced into the right pilot port of the control valve 175R. When operated in the boom raising direction, the right operation lever 26R causes a pilot oil to be introduced into the right pilot port of control valve 175L and also causes a pilot oil to be introduced into the left pilot port of control valve 175R. When operated in the bucket closing direction, the right operation lever 26R causes a pilot oil to be introduced into the right pilot port of the control valve 174, and when operated in the bucket opening direction, the right operation lever 26R causes a pilot oil to be introduced into the left pilot port of the control valve 174. As described above, when operated in the front-rear direction, the right operation lever 26R functions as a “boom operation lever,” and when operated in the left-right direction, the right operation lever 26R functions as a “bucket operation lever.”

The traveling lever 26D is used for operating the crawler 1C. Specifically, the left traveling lever 26DL is used for operating the left crawler 1CL. The left traveling lever 26DL may be configured to be interlocked with the left traveling pedal. When the left traveling lever 26DL is operated in the front-rear direction, the left traveling lever 26DL introduces a control pressure corresponding to the operation amount into the pilot port of the control valve 171 by using the pilot oil discharged from the pilot pump 15. The right traveling lever 26DR is used for operating the right crawler 1CR. The right traveling lever 26DR may be configured to be interlocked with the right traveling pedal. When the right traveling lever 26DR is operated in the front-rear direction, the right traveling lever 26DR introduces a control pressure corresponding to the operation amount into the pilot port of the control valve 172 by using the pilot oil discharged from the pilot pump 15.

The discharge pressure sensor 28 includes a left discharge pressure sensor 28L and a right discharge pressure sensor 28R. The left discharge pressure sensor 28L detects a discharge pressure of the left main pump 14L and outputs a detected value to the controller 30. The same applies to the right discharge pressure sensor 28R.

The operation sensors 29 include operation sensors 29LA, 29LB, 29RA, 29RB, 29DL, and 29DR. The operation sensor 29LA detects an operation content of the left operation lever 26L in the front-rear direction by the operator in the form of an angle, and outputs the detected value to the controller 30. The operation content is, for example, a lever operation direction, a lever operation amount (lever operation angle), and the like. Similarly, the operation sensor 29LB detects an operation content of the left operation lever 26L in the left-right direction by the operator in the form of an angle, and outputs a detected value to the controller 30. The operation sensor 29RA detects an operation content of the right operation lever 26R in the front-rear direction by the operator in the form of an angle, and outputs a detected value to the controller 30. The operation sensor 29RB detects an operation content of the right operation lever 26R in the left-right direction by the operator in the form of an angle, and outputs a detected value to the controller 30. The operation sensor 29DL detects an operation content of the left traveling lever 26DL in the front-rear direction by the operator in the form of an angle, and outputs a detected value to the controller 30. The operation sensor 29DR detects an operation content of the right traveling lever 26DR in the front-rear direction by the operator in the form of an angle, and outputs a detected value to the controller 30.

The controller 30 receives the output of the operation sensor 29, outputs a control command to the pump regulator 13 as necessary, and changes the discharge amount of the main pump 14.

Here, negative control using the throttle 18 and the control pressure sensor 19 will be described. The throttle 18 includes a left throttle 18L and a right throttle 18R, and the control pressure sensor 19 includes a left control pressure sensor 19L and a right control pressure sensor 19R.

In the left center bypass pipe CBL, the left throttle 18L is disposed between the control valve 176L located most downstream and the hydraulic fluid tank. Therefore, the flow of the hydraulic fluid discharged by the left main pump 14L is restricted by the left throttle 18L. The left throttle 18L generates a control pressure for controlling the left pump regulator 13L. The left control pressure sensor 19L is a sensor for detecting the control pressure, and outputs the detected value to the controller 30. The controller 30 controls a discharge amount of the left main pump 14L by adjusting the swash plate tilt angle of the left main pump 14L according to this control pressure. The controller 30 decreases the discharge amount of the left main pump 14L as this control pressure increases, and increases the discharge amount of the left main pump 14L as this control pressure decreases. The discharge amount of the right main pump 14R is controlled in the same manner.

Specifically, in a case of a standby state in which none of the hydraulic actuators in the excavator 100 is operated as illustrated in FIG. 3, the hydraulic fluid discharged from the left main pump 14L reaches the left throttle 18L through the left center bypass pipeline CBL. The flow of the hydraulic fluid discharged from the left main pump 14L increases the control pressure generated upstream of the left throttle 18L. As a result, the controller 30 reduces the discharge amount of the left main pump 14L to the minimum allowable discharge amount, and prevents a pumping loss when the discharged hydraulic fluid passes through the left center bypass pipeline CBL. When any one of the hydraulic actuators is operated, the hydraulic fluid discharged from the left main pump 14L flows into the hydraulic actuators to be operated via the control valves corresponding to the hydraulic actuators to be operated. The flow of the hydraulic fluid discharged from the left main pump 14L reduces or eliminates the amount of the hydraulic fluid reaching the left throttle 18L, and reduces the control pressure generated upstream of the left throttle 18L. As a result, the controller 30 increases the discharge amount of the left main pump 14L, causes sufficient hydraulic fluid to flow into the hydraulic actuators to be operated, and ensures the driving of the hydraulic actuators to be operated. The controller 30 also controls the discharge amount of the right main pump 14R in the same manner.

With the above-described configuration, the hydraulic system of FIG. 3 can prevent wasteful energy consumption in the main pump 14 in the standby state. The wasteful energy consumption includes a pumping loss generated in the center bypass pipe CB by the hydraulic fluid discharged from the main pump 14. Further, in the hydraulic system of FIG. 3, when the hydraulic actuator is operated, a necessary and sufficient amount of hydraulic fluid can be reliably supplied from the main pump 14 to the hydraulic actuator to be operated.

The control valve 60 is configured to switch the operation device 26 between an enabled state and a disabled state. The enabled state of the operation device 26 is a state in which the operator can operate the operation device 26 to move an associated driven body, and the disabled state of the operation device 26 is a state in which the operator cannot operate the operation device 26 to move the associated driven body.

In the present embodiment, the control valve 60 is a solenoid valve that can switch between a communication state and a shutoff state of a pilot line CD1, which connects the pilot pump 15 and the operation device 26. Specifically, the control valve 60 is configured to switch the pilot line CD1 between the communication state and the shutoff state in response to a command from the controller 30.

The control valve 60 may be configured to operate in conjunction with a gate lock lever (not illustrated). Specifically, the pilot line CD1 may be configured to be in the shutoff state when the gate lock lever is pushed down, and the pilot line CD1 may be configured to be in the communication state when the gate lock lever is pulled up. However, the control valve 60 may be a solenoid valve differing from the solenoid valve that can switch the pilot line CD1 between the communication state and the shutoff state in conjunction with the gate lock lever.

Next, a configuration for the controller 30 to operate the actuators will be described with reference to FIGS. 4A to 4F. FIGS. 4A to 4F are diagrams in which a portion of the hydraulic system is extracted. Specifically, FIG. 4A is a diagram in which a hydraulic system portion related to the operation of the arm cylinder 8 is extracted, and FIG. 4B is a diagram in which a hydraulic system portion related to the operation of the boom cylinder 7 is extracted. FIG. 4C is a diagram in which a hydraulic system portion related to the operation of the bucket cylinder 9 is extracted, and FIG. 4D is a diagram in which a hydraulic system portion related to the operation of the slewing hydraulic motor 2A is extracted. FIG. 4E is a diagram in which a hydraulic system portion related to the operation of the left traveling hydraulic motor 2ML is extracted, and FIG. 4F is a diagram in which a hydraulic system portion related to the operation of the right traveling hydraulic motor 2MR is extracted.

As illustrated in FIGS. 4A to 4F, the hydraulic system includes a solenoid valve 31. The solenoid valve 31 includes solenoid valves 31AL to 31FL and solenoid valves 31AR to 31FR.

The solenoid valve 31 is disposed in a pipeline connecting the pilot pump 15 and a pilot port of a corresponding control valve in the control valve unit 17, and is configured to be able to change a flow passage area of the pipeline by changing an opening area. In the present embodiment, the solenoid valve 31 is an electromagnetic proportional valve, and operates in response to a control command output from the controller 30. Therefore, the controller 30 can supply the pilot oil discharged by the pilot pump 15 to the pilot port of the corresponding control valve in the control valve unit 17 via the solenoid valve 31, in response to the operation of the operation device 26 by the operator or independently of the operation of the operation device 26 by the operator. The controller 30 can cause the pilot pressure generated by the solenoid valve 31 to act on the pilot port of the corresponding control valve.

With this configuration, the controller 30 can operate the hydraulic actuator corresponding to the specific operation device 26 even when the specific operation device 26 is not operated in addition to when the specific operation device 26 is operated. Further, even when an operation is being performed on the specific operation device 26, the controller 30 can forcibly stop the operation of the hydraulic actuator corresponding to the specific operation device 26.

For example, as illustrated in FIG. 4A, the left operation lever 26L is used to operate the arm 5. Specifically, the left operation lever 26L uses the pilot oil discharged from the pilot pump 15 to apply a pilot pressure corresponding to the operation in the front-rear direction to the pilot port of the control valve 176. Specifically, when the left operation lever 26L is operated in the arm closing direction (rearward direction), the left operation lever 26L applies a pilot pressure corresponding to the operation amount to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R. When the left operation lever 26L is operated in the arm opening direction (forward direction), the left operation lever 26L applies a pilot pressure corresponding to the operation amount to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R.

The operation device 26 is provided with a switch SW. In the present embodiment, the switch SW includes a switch SW1 and a switch SW2. The switch SW1 is a push button switch provided at the tip of the left operation lever 26L. The operator can operate the left operation lever 26L while pressing the switch SW1. The switch SW1 may be provided on the right operation lever 26R or may be provided at another position in the cabin 10. The switch SW2 is a push button switch provided at the tip of the left traveling lever 26DL. The operator can operate the left traveling lever 26DL while pressing the switch SW2. The switch SW2 may be provided on the right traveling lever 26DR or at another position in the cabin 10.

The operation sensor 29LA detects the operation content of the left operation lever 26L in the front-rear direction by the operator, and outputs the detected value to the controller 30.

The solenoid valve 31AL operates in response to a control command (current command) output from the controller 30. The pilot pressure is adjusted by the pilot oil introduced from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the solenoid valve 31AL. The solenoid valve 31AR operates in response to a control command (current command) output from the controller 30. The pilot pressure is adjusted by the pilot oil introduced from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the solenoid valve 31AR. The solenoid valve 31AL can adjust the pilot pressure such that the control valves 176L and 176R can be stopped at any given positions. Similarly, the solenoid valve 31AR can adjust the pilot pressure such that the control valves 176L and 176R can be stopped at any given positions.

With this configuration, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the solenoid valve 31AL in response to the arm closing operation by the operator. Further, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the solenoid valve 31AL, independent of the arm closing operation by the operator. That is, the controller 30 can close the arm 5 in response to the arm closing operation by the operator or independently of the arm closing operation by the operator. Thus, the solenoid valve 31AL functions as an “arm solenoid valve” or an “arm closing solenoid valve.”

Further, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the solenoid valve 31AR in response to the arm opening operation by the operator. Further, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the solenoid valve 31AR, independent of the arm opening operation by the operator. That is, the controller 30 can open the arm 5 in response to the arm opening operation by the operator or independently of the arm opening operation by the operator. In this manner, the solenoid valve 31AR functions as an “arm solenoid valve” or an “arm opening solenoid valve.”

Further, with this configuration, even when the arm closing operation is performed by the operator, the controller 30 can forcibly stop the closing operation of the arm 5 by reducing the pilot pressure acting on the pilot ports on the closing side of the control valves 176 (the left pilot port of the control valve 176L and the right pilot port of the control valve 176R) as necessary. The same applies to a case where the opening operation of the arm 5 is forcibly stopped when the arm opening operation is performed by the operator.

Alternatively, even when the operator is performing the arm closing operation, the controller 30 may, as necessary, control the solenoid valve 31AR to increase the pilot pressure acting on the pilot ports on the opening side of the control valves 176 (the right pilot port of the control valve 176L and the left pilot port of the control valve 176R) opposite to the pilot ports on the closing side of the control valves 176, and forcibly return the control valve 176 to the neutral position, to forcibly stop the closing operation of the arm 5. The same applies to a case where the opening operation of the arm 5 is forcibly stopped when the arm opening operation is performed by the operator.

Although description will be omitted with reference to FIGS. 4B to 4F, the same applies to a case where the operation of the boom 4 is forcibly stopped when the boom raising operation or the boom lowering operation is performed by the operator, a case where the operation of the bucket 6 is forcibly stopped when the bucket closing operation or the bucket opening operation is performed by the operator, and a case where the slewing operation of the upper slewing body 3 is forcibly stopped when the slewing operation is performed by the operator. The same applies to a case where the traveling operation of the lower traveling body 1 is forcibly stopped when the traveling operation is performed by the operator.

Further, the controller 30 may be configured to apply a small amount of the pilot pressure to the pilot ports on both sides of the control valves 176 even before the arm operation is performed, in order to improve the responsiveness of the arm operation (arm closing and arm opening operation). The same applies to other operations such as boom operations (boom raising operation and boom lowering operation). That is, the controller 30 can increase the responsiveness of the hydraulic actuators by using a larger amount of pilot oil.

As illustrated in FIG. 4B, the right operation lever 26R is used to operate the boom 4. Specifically, the right operation lever 26R uses the pilot oil discharged from the pilot pump 15 to apply a pilot pressure corresponding to the operation in the front-rear direction to the pilot port of the control valve 175. Specifically, when the right operation lever 26R is operated in the boom raising direction (rearward direction), the right operation lever 26R applies a pilot pressure corresponding to the operation amount to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R. When the right operation lever 26R is operated in the boom lowering direction (forward direction), the right operation lever 26R applies a pilot pressure corresponding to the operation amount to the right pilot port of the control valve 175R.

The operation sensor 29RA detects the operation content of the right operation lever 26R in the front-rear direction by the operator, and outputs the detected value to the controller 30.

The solenoid valve 31BL operates in response to a control command (current command) output from the controller 30. The pilot pressure is adjusted by the pilot oil introduced from the pilot pump 15 to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the solenoid valve 31BL. The solenoid valve 31BR operates in response to a control command (current command) output from the controller 30. The pilot pressure is adjusted by the pilot oil introduced from the pilot pump 15 to the right pilot port of the control valve 175R via the solenoid valve 31BR. The solenoid valve 31BL can adjust the pilot pressure such that the control valves 175L and 175R can be stopped at any given positions. The solenoid valve 31BR can adjust the pilot pressure such that the control valves 175R can be stopped at any given positions.

With this configuration, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the solenoid valve 31BL in response to the boom raising operation by the operator. The controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the solenoid valve 31BL, independent of the boom raising operation by the operator. That is, the controller 30 can raise the boom 4 in response to the boom raising operation by the operator or independently of the boom raising operation by the operator. In this manner, the solenoid valve 31BL functions as a “boom solenoid valve” or a “boom raising solenoid valve.”

Further, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 175R via the solenoid valve 31BR in response to the boom lowering operation by the operator. Further, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 175R via the solenoid valve 31BR, independent of the boom lowering operation by the operator. That is, the controller 30 can lower the boom 4 in response to the boom lowering operation by the operator or independently of the boom lowering operation by the operator. In this manner, the solenoid valve 31BR functions as a “boom solenoid valve” or a “boom lowering solenoid valve.”

As illustrated in FIG. 4C, the right operation lever 26R is also used to operate the bucket 6. Specifically, the right operation lever 26R uses the pilot oil discharged from the pilot pump 15 to apply a pilot pressure corresponding to the operation in the left-right direction to the pilot port of the control valve 174. Specifically, when the right operation lever 26R is operated in the bucket closing direction (left direction), the right operation lever 26R applies a pilot pressure corresponding to the operation amount to the left pilot port of the control valve 174. When the right operation lever 26R is operated in the bucket opening direction (right direction), the right operation lever 26R applies a pilot pressure corresponding to the operation amount to the right pilot port of the control valve 174.

The operation sensor 29RB detects the operation content of the right operation lever 26R in the left-right direction by the operator, and outputs the detected value to the controller 30.

The solenoid valve 31CL operates in response to a control command (current command) output from the controller 30. The pilot pressure is adjusted by the pilot oil introduced from the pilot pump 15 to the left pilot port of the control valve 174 via the solenoid valve 31CL. The solenoid valve 31CR operates in response to a control command (current command) output from the controller 30. The pilot pressure is adjusted by the pilot oil introduced from the pilot pump 15 to the right pilot port of the control valve 174 via the solenoid valve 31CR. The solenoid valve 31CL can adjust the pilot pressure such that the control valve 174 can be stopped at any given position. Similarly, the solenoid valve 31CR can adjust the pilot pressure such that the control valve 174 can be stopped at any given position.

With this configuration, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 174 via the solenoid valve 31CL in response to the bucket closing operation by the operator. The controller 30 can supply the pilot oil discharged by the pilot pump 15 to the left pilot port of the control valve 174 via the solenoid valve 31CL, independent of the bucket closing operation by the operator. That is, the controller 30 can close the bucket 6 in response to the bucket closing operation by the operator or independently of the bucket closing operation by the operator. In this manner, the solenoid valve 31CL functions as a “bucket solenoid valve” or a “bucket closing solenoid valve.”

Further, the controller 30 can supply the pilot oil discharged by the pilot pump 15 to the right pilot port of the control valve 174 via the solenoid valve 31CR in response to the bucket opening operation by the operator. The controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 174 via the solenoid valve 31CR, independent of the bucket opening operation by the operator. That is, the controller 30 can open the bucket 6 in response to the bucket opening operation by the operator or independently of the bucket opening operation by the operator. Thus, the solenoid valve 31CR functions as a “bucket solenoid valve” or a “bucket opening solenoid valve.”

As illustrated in FIG. 4D, the left operation lever 26L is also used to operate the slewing mechanism 2. Specifically, the left operation lever 26L uses the pilot oil discharged from the pilot pump 15 to apply a pilot pressure corresponding to the operation in the left-right direction to the pilot port of the control valve 173. Specifically, when the left operation lever 26L is operated in the left slewing direction (left direction), the left operation lever 26L applies a pilot pressure corresponding to the operation amount to the left pilot port of the control valve 173. When the left operation lever 26L is operated in the right slewing direction (right direction), the left operation lever 26L applies a pilot pressure corresponding to the operation amount to the right pilot port of the control valve 173.

The operation sensor 29LB detects the operation content of the left operation lever 26L in the left-right direction by the operator, and outputs the detected value to the controller 30.

The solenoid valve 31DL operates in response to a control command (current command) output from the controller 30. The pilot pressure is adjusted by the pilot oil introduced from the pilot pump 15 to the left pilot port of the control valve 173 via the solenoid valve 31DL. The solenoid valve 31DR operates in response to a control command (current command) output from the controller 30. The pilot pressure is adjusted by the pilot oil introduced from the pilot pump 15 to the right pilot port of the control valve 173 via the solenoid valve 31DR. The solenoid valve 31DL can adjust the pilot pressure such that the control valve 173 can be stopped at any given position. Similarly, the solenoid valve 31DR can adjust the pilot pressure such that the control valve 173 can be stopped at any given position.

With this configuration, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 173 via the solenoid valve 31DL in response to the left slewing operation by the operator. The controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 173 via the solenoid valve 31DL, independent of the left slewing operation by the operator. That is, the controller 30 can slew the slewing mechanism 2 to the left in response to the left slewing operation by the operator or independently of the left slewing operation by the operator. In this manner, the solenoid valve 31DL functions as a “slewing solenoid valve” or a “left slewing solenoid valve.”

Further, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 173 via the solenoid valve 31DR in response to the right slewing operation by the operator. The controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 173 via the solenoid valve 31DR, independent of the right slewing operation by the operator. That is, the controller 30 can slew the slewing mechanism 2 to the right in response to the right slewing operation by the operator or independently of the right slewing operation by the operator. In this manner, the solenoid valve 31DR functions as a “slewing solenoid valve” or a “right slewing solenoid valve.”

As illustrated in FIG. 4E, the left traveling lever 26DL is used to operate the left crawler 1CL. Specifically, the left traveling lever 26DL uses the pilot oil discharged from pilot pump 15 to apply a pilot pressure corresponding to the operation in the front-rear direction to the pilot port of the control valve 171. Specifically, when the left traveling lever 26DL is operated in the forward traveling direction (forward direction), the left traveling lever 26DL applies a pilot pressure corresponding to the operation amount to the left pilot port of the control valve 171. When the left traveling lever 26DL is operated in the rearward traveling direction (rearward direction), the left traveling lever 26DL applies a pilot pressure corresponding to the operation amount to the right pilot port of the control valve 171.

The operation sensor 29DL electrically detects the operation content of the left traveling lever 26DL in the front-rear direction by the operator, and outputs the detected value to the controller 30.

The solenoid valve 31EL operates in response to a current command output from the controller 30. The solenoid valve 31EL adjusts the pilot pressure by the pilot oil introduced from the pilot pump 15 to the left pilot port of the control valve 171 via the solenoid valve 31EL. The solenoid valve 31ER operates in response to a current command output from the controller 30. The solenoid valve 31ER adjusts the pilot pressure by the pilot oil introduced from the pilot pump 15 to the right pilot port of the control valve 171 via the solenoid valve 31ER. The solenoid valves 31EL and 31ER can adjust the pilot pressure such that the control valve 171 can be stopped at any given position.

With this configuration, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 171 via the solenoid valve 31EL, independent of the left forward traveling operation by the operator. That is, the left crawler 1CL can be moved forward. The controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 171 via the solenoid valve 31ER, independent of the left rearward traveling operation by the operator. That is, the left crawler 1CL can be moved rearward. Thus, the solenoid valve 31EL functions as a “left traveling solenoid valve” or a “left forward traveling solenoid valve”, and the solenoid valve 31ER functions as a “left traveling solenoid valve” or a “left rearward traveling solenoid valve.”

As illustrated in FIG. 4F, the right traveling lever 26DR is used to operate the right crawler 1CR. Specifically, the right traveling lever 26DR uses the pilot oil discharged by the pilot pump 15 to apply a pilot pressure corresponding to the operation in the front-rear direction to the pilot port of the control valve 172. Specifically, when the right traveling lever 26DR is operated in the forward traveling direction (forward direction), the right traveling lever 26DR applies a pilot pressure corresponding to the operation amount to the right pilot port of the control valve 172. When the right traveling lever 26DR is operated in the rearward traveling direction (rearward direction), the pilot pressure corresponding to the operation amount is applied to the left pilot port of the control valve 172.

The operation sensor 29DR electrically detects the operation content of the right traveling lever 26DR in the front-rear direction by the operator, and outputs the detected value to the controller 30.

The solenoid valve 31FL operates in response to a current command output from the controller 30. The solenoid valve 31FL adjusts the pilot pressure by the pilot oil introduced from the pilot pump 15 to the left pilot port of the control valve 172 via the solenoid valve 31FL. The solenoid valve 31FR operates in response to a current command output from the controller 30. The solenoid valve 31FR adjusts the pilot pressure by the pilot oil introduced from the pilot pump 15 to the right pilot port of the control valve 172 via the solenoid valve 31FR. The solenoid valves 31FL and 31FR can adjust the pilot pressure such that the control valve 172 can be stopped at any given position.

With this configuration, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 172 via the solenoid valve 31FL, independent of the operation of the vehicle to move forward to the right. That is, the right crawler 1CR can be moved forward. The controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 172 via the solenoid valve 31FR, independent of the operation of the vehicle to move rearward to the right. That is, the right crawler 1CR can be moved rearward. In this manner, the solenoid valve 31FL functions as a “right traveling solenoid valve” or a “right forward traveling solenoid valve”, and the solenoid valve 31FR functions as a “right traveling solenoid valve” or a “right rearward traveling solenoid valve.”

The excavator 100 may have a configuration in which the bucket tilt mechanism is automatically operated. In this case, a hydraulic system portion related to the bucket tilt cylinder constituting the bucket tilt mechanism may be configured in the same manner as the hydraulic system portion related to the operation of the boom cylinder 7.

Further, although the electric operation lever has been described as the form of the operation device 26, a hydraulic operation lever may be employed instead of the electric operation lever. In this case, the operation amount of the hydraulic operation lever may be detected in the form of pressure by a pressure sensor and input to the controller 30. Further, a solenoid valve may be disposed between the operation device 26 serving as the hydraulic operation lever and the pilot port of each control valve. The solenoid valve is configured to operate in response to an electrical signal from the controller 30. With this configuration, when a manual operation is performed using the operation device 26 as a hydraulic operation lever, the operation device 26 can move each control valve by increasing or decreasing the pilot pressure in accordance with the operation amount. Further, each control valve may be constituted by an electromagnetic spool valve. In this case, the electromagnetic spool valve operates in response to an electric signal from the controller 30 corresponding to the operation amount of the electric operation lever.

Next, an overview of a machine guidance function and a machine control function of the excavator 100 will be described with reference to FIG. 5. FIG. 5 is a diagram illustrating a configuration example of a control system of the excavator 100. Specifically, FIG. 5 illustrates an example of a configuration related to a machine guidance function and a machine control function of the excavator 100.

The controller 30 is configured to be able to execute a machine guidance function of guiding a manual operation of the excavator 100 by the operator.

Specifically, the controller 30 informs the operator of work information such as distances between the target construction surface such as the design surface and a predetermined work part of the bucket 6 (for example, the claw tip of the bucket 6 or the back surface of the bucket 6) (hereinafter, simply referred to as a “work part”) which is a tip portion of the attachment AT through the display device 40, the indoor alarm device 45B, and the like.

Specifically, the controller 30 acquires information from the boom angle sensor S1, the arm angle sensor S2, the bucket angle sensor S3, the body inclination sensor S4, the slewing angular velocity sensor S5, the operation sensor 29, the object detection device 70, the positioning device 85, the switch SW, and the like. Then, the controller 30 calculates a distance between the bucket 6 and the target construction surface based on the acquired information, for example, and notifies the operator of the calculated distance by an image displayed on the display device 40, a sound output from the indoor alarm device 45B, and the like. The data related to the target construction surface is stored in an internal memory of the controller 30, an external storage device connected to the controller 30, or the like, for example, based on a setting input through an information input device (not illustrated) by an operator or by being downloaded from the outside (for example, a predetermined management server). The data related to the target construction surface is expressed by, for example, a reference coordinate system. The reference coordinate system is, for example, a world geodetic system. The world geodetic system is a three dimensional orthogonal XYZ coordinate system with the origin at the center of gravity of the earth, the X-axis in the direction of the intersection of the Greenwich meridian and the equator, the Y-axis in the direction of 90 degrees east longitude, and the Z-axis in the direction of the north pole. The operator may set an any given point of the construction site as a reference point, and may set the target construction surface based on a relative positional relationship with the reference point through the information input device. Thus, the controller 30 can notify the operator of the work information through the display device 40, the indoor alarm device 45B, and the like, and guide the operation of the excavator 100 by the operator through the operation device 26.

The controller 30 is configured to be able to execute a machine control function of supporting manual operation of the excavator 100 by an operator or automatically or autonomously operating the excavator 100.

Specifically, when the operator manually performs the excavation operation, the leveling operation, or the like, the controller 30 automatically operates at least one of the boom 4, the arm 5, and the bucket 6 such that the target construction surface conforms to the tip portion of the attachment AT, that is, a shape element to be controlled (hereinafter, simply referred to as a “control target”) set in the work part or the like of the bucket 6. The control target may include, for example, a plane or a curved surface constituting a claw tip as a work part of the bucket 6, a line segment defined on the plane or the curved surface, a point defined on the plane or the curved surface, and the like. The control target may include, for example, a plane or a curved surface constituting the back surface as the work part of the bucket 6, a line segment defined on the plane or the curved surface, a point defined on the plane or the curved surface, and the like. The control target may be set to the arm top pin (bucket coupling pin).

Specifically, when the operator operates the left operation lever 26L to move the arm 5 while operating (pressing) the switch SW, the controller 30 automatically operates the boom 4, the arm 5, and the bucket 6 in response to the operation of the left operation lever 26L by the operator such that the target construction surface and the control target coincide with each other. More specifically, the controller 30 controls the solenoid valve 31 to automatically operate the boom 4, the arm 5, and the bucket 6 as described above. Thus, the operator can cause the excavator 100 to perform an excavating operation, a leveling operation, or the like along the target construction surface by simply operating the left operation lever 26L in the front-rear direction.

The work part of the bucket 6 may be set in accordance with, for example, a setting input by an operator or the like through the information input device. The work part of the bucket 6 may be automatically set according to the work content of the excavator 100, for example. Specifically, the work part of the bucket 6 may be set as the claw tip of the bucket 6 when the work content of the excavator 100 is the excavation work or the like, and may be set as the back surface of the bucket 6 when the work content of the excavator 100 is the leveling work, the rolling compaction work, or the like. In this case, the work content of the excavator 100 may be automatically determined based on the captured image of the front camera 70F or the like, or may be set according to the selected content or the input content by the operator or the like selecting or inputting through the information input device.

When the work part is the claw tip of the bucket 6, the control target in the work part of the bucket 6 (hereinafter, simply referred to as “control target of the bucket 6”) may be set to one point on a curved surface or a plane forming a tip portion of a specific one claw among the plurality of claws of the bucket 6. Further, for example, when the work part is the back surface of the bucket 6, the control target of the bucket 6 can be optionally set on a curved surface or a plane constituting the back surface of the bucket 6. In this case, the controller 30 may optionally set the control target on the back surface of the bucket 6 in accordance with a setting operation by the operator or the like through the information input device, or may automatically set (change) the control target on the back surface of the bucket 6 based on a predetermined condition.

Next, an example of a detailed configuration related to the machine control function will be described with reference to FIGS. 6A and 6B. FIG. 6A and FIG. 6B are diagrams illustrating a configuration example of the controller 30. In particular, FIGS. 6A and 6B illustrate an example of a detailed configuration of the machine control function. The following description with reference to FIGS. 6A and 6B relates to a machine control function executed when the left operation lever 26L (arm operation lever) for moving the arm 5 is operated in a state where the switch SW is operated.

The controller 30 includes, as functional units related to the machine control function, an operation content acquisition unit 3001, a target construction surface acquisition unit 3002, a target trajectory setting unit 3003, a current position calculation unit 3004, a target position calculation unit 3005, an operation command generation unit 3006, a pilot command generation unit 3007, a posture angle calculation unit 3008, a control target speed calculation unit 3009, and a restriction unit 3010. In the illustrated example, each of ten functional units is implemented by software. However, each of the ten functional units may be implemented by hardware (electronic circuit or the like) or may be implemented by a combination of software and hardware. In the illustrated example, each of the ten functional units repeatedly executes processing described later at predetermined control intervals when the switch SW is operated.

The operation content acquisition unit 3001 acquires an operation content of the arm operation lever based on a detection signal captured from the operation sensor 29LA. For example, the operation content acquisition unit 3001 acquires (calculates) an operation direction (whether the operation is an arm opening operation or an arm closing operation) and an operation amount as the operation content.

The target construction surface acquisition unit 3002 acquires data related to the target construction surface from, for example, an internal memory or an external storage device.

The target trajectory setting unit 3003 sets information about a target trajectory of the control target of the bucket 6 for moving the control target of the bucket 6 which is the tip portion of the attachment AT along the target construction surface based on the data related to the target construction surface. For example, the target trajectory setting unit 3003 may set an inclination angle of the target construction surface in the front-rear direction with respect to the body (upper slewing body 3) of the excavator 100 as the information about the target trajectory.

The current position calculation unit 3004 calculates a position (current position) of the control target of the bucket 6. Specifically, a position of the control target of the bucket 6 may be calculated based on the boom angle β1, the arm angle β2, and the bucket angle 3 calculated by the posture angle calculation unit 3008.

The target position calculation unit 3005 calculates a target position of the control target of the bucket 6 based on the operation content (operation direction and operation amount) of the arm operation lever, information related to the set target trajectory, and the current position of the control target of the bucket 6. The target position is a position on the target construction surface (in other words, a target trajectory) to be reached in the current control cycle when it is assumed that the arm 5 operates in accordance with the operation direction and the operation amount of the arm operation lever. The target position calculation unit 3005 may calculate the target position of the control target of the bucket 6 using a map, an arithmetic expression, or the like stored in advance in the internal memory or the like.

The operation command generation 3006 generates a command value related to the operation of the boom 4 (hereinafter referred to as a “boom command value β1r”), a command value related to the operation of the arm 5 (hereinafter referred to as an “arm command value β2r”), and a command value related to the operation of the bucket 6 (hereinafter referred to as a “bucket command value β3r”) based on the target position of the control target of the bucket 6. In the illustrated example, the boom command value β1r, the arm command value β2r, and the bucket command value β3r are the boom angle, the arm angle, and the bucket angle, respectively, when the control target of the bucket 6 can reach the target position. The boom command value β1r, the arm command value β2r, and the bucket command value β3r may be angular velocities or angular accelerations of the boom 4, the arm 5, and the bucket 6 required for the control target of the bucket 6 to reach the target position.

The operation command generation unit 3006 includes a controller command generation unit 3006A and a responder command generation unit 3006B. The controller command generation unit 3006A generates a command value (hereinafter, referred to as a “controller command value”) related to the operation of a work element (hereinafter, referred to as a “controller element”) that operates in accordance with the operation content of the operation device 26. The operation lever for operating the controller element is also referred to as a “controller operation lever.” In the illustrated example, the controller element is the arm 5, the controller operation lever is an arm operation lever, and the controller command generation unit 3006A generates an arm command value β2r and outputs the arm command value β2r to the arm pilot command generation unit 3007B. Specifically, the controller command generation unit 3006A generates the arm command value β2r corresponding to the operation content (operation direction and operation amount) of the arm operation lever. The controller command generation unit 3006A may generate and output the arm command value β2r based on a predetermined map, a conversion formula, or the like that defines a relationship between the operation content of the arm operation lever and the arm command value β2r.

The responder command generation unit 3006B generates a command value (hereinafter, referred to as a “responder command value”) related to the operation of a work element (hereinafter, referred to as a “responder element”) that operates such that the control target of the bucket 6 moves along the target construction surface in accordance with (in synchronization with) the operation of the controller element (arm 5) among the work elements constituting the attachment AT. In the illustrated example, the responder elements are the boom 4 and the bucket 6, and the responder command generation unit 3006B generates a boom command value β1r and a bucket command value β3r, and outputs the generated command values to a boom pilot command generation unit 3007A and a bucket pilot command generation unit 3007C, respectively. Specifically, the responder command generation unit 3006B generates the boom command value β2r and the bucket command value β1r such that at least one of the boom 4 and the bucket 6 operates in accordance with (in synchronization with) the operation of the arm 5 corresponding to the arm command value β3r, and the control target of the bucket 6 can reach the target position (that is, move along the target construction surface). Thus, the controller 30 can move the control target of the bucket 6 along the target construction surface by operating the boom 4 and the bucket 6 of the attachment AT in accordance with (that is, in synchronization with) the operation of the arm 5 corresponding to the operation content of the arm operation lever. That is, the arm 5 (arm cylinder 8) operates in response to an operation input to the arm operation lever, and movements of the boom 4 (boom cylinder 7) and the bucket 6 (bucket cylinder 9) are controlled in accordance with the operation of the arm 5 (arm cylinder 8) such that the tip portion of the attachment AT such as the claw tip of the bucket 6 moves along the target construction surface.

The controller element may be the upper slewing body 3 that can slew with respect to the lower traveling body 1. In this case, the responder elements may be the boom 4, the arm 5, and the bucket 6. Thus, the controller 30 can move the control target of the bucket 6 along the target construction surface by operating the boom 4, the arm 5, and the bucket 6 of the attachment AT in accordance with (that is, in synchronization with) the slewing operation of the upper slewing body 3 corresponding to the operation content of the slewing operation lever. That is, the upper slewing body 3 (slewing hydraulic motor 2A) operates in response to an operation input to the slewing operation lever, and movements of the boom 4 (boom cylinder 7), the arm 5 (arm cylinder 8), and the bucket 6 (bucket cylinder 9) are controlled in accordance with the operation of the upper slewing body 3 (slewing hydraulic motor 2A) such that the tip of the attachment AT such as the claw tip of the bucket 6 moves along the target construction surface.

The pilot command generation unit 3007 generates a command value of a pilot pressure (hereinafter, referred to as a “pilot pressure command value”) to be applied to each of the control valves 174 to 176 in order to reach the boom angle, the arm angle, and the bucket angle corresponding to the boom command value β1r, the arm command value β2r, and the bucket command value β3r. The pilot command generation unit 3007 includes the boom pilot command generation unit 3007A, an arm pilot command generation unit 3007B, and a bucket pilot command generation unit 3007C.

The boom pilot command generation unit 3007A generates a pilot pressure command value to be applied to the control valves 175L and 175R corresponding to the boom cylinder 7 that drives the boom 4, based on a deviation between the boom command value β1r and a calculated value (measured value) of the current boom angle calculated by a boom angle calculation unit 3008A. Then, the boom pilot command generation unit 3007A outputs a control current corresponding to the generated pilot pressure command value to the solenoid valves 31BL and 31BR. Thus, the solenoid valves 31BL and 31BR can apply the pilot pressure corresponding to the pilot pressure command value to the corresponding pilot ports of the control valves 175L and 175R. When the pilot pressure acts on the pilot port, the control valves 175L and 175R operate. Further, when the control valves 175L and 175R are operated, the boom cylinder 7 is operated, and the boom 4 is operated so as to reach the boom angle corresponding to the boom command value β1r.

The arm pilot command generation unit 3007B generates a pilot pressure command value to be applied to the control valves 176L and 176R corresponding to the arm cylinder 8 that drives the arm 5, based on a deviation between the arm command value β2r and a calculated value (measured value) of the current arm angle calculated by the arm angle calculation unit 3008B. Then, the arm pilot command generation unit 3007B outputs a control current corresponding to the generated pilot pressure command value to the solenoid valves 31AL and 31AR. Thus, the solenoid valves 31AL and 31AR can apply the pilot pressure corresponding to the pilot pressure command value to the corresponding pilot ports of the control valves 176L and 176R. When the pilot pressure acts on the pilot port, the control valves 176L and 176R operate. Further, when the control valves 176L and 176R operate, the arm cylinder 8 operates, and the arm 5 operates so as to reach the arm angle corresponding to the arm command value β2r.

The bucket pilot command generation unit 3007C generates a pilot pressure command value to be applied to the control valve 174 corresponding to the bucket cylinder 9 that drives the bucket 6, based on a deviation between the bucket command value β3r and the calculated value (measured value) of the current bucket angle calculated by the bucket angle calculation unit 3008C. Then, the bucket pilot command generation unit 3007C outputs a control current corresponding to the generated pilot pressure command value to the solenoid valves 31CL and 31CR. Thus, the solenoid valves 31CL and 31CR can apply the pilot pressure corresponding to the pilot pressure command value to the corresponding pilot port of the control valve 174. When the pilot pressure acts on the pilot port, the control valve 174 operates. Further, when the control valve 174 operates, the bucket cylinder 9 operates, and the bucket 6 operates so as to reach the bucket angle corresponding to the bucket command value β3r.

The posture angle calculation unit 3008 calculates (measures) a boom angle β1, an arm angle β2, and a bucket angle β3 based on detection signals of the boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3. The posture angle calculation unit 3008 includes the boom angle calculation unit 3008A, an arm angle calculation unit 3008B, and a bucket angle calculation unit 3008C. The boom angle calculation unit 3008A calculates (measures) the boom angle β1 based on the detection signal captured from the boom angle sensor S1. The arm angle calculation unit 3008B calculates (measures) the arm angle β2 based on the detection signal captured from the arm angle sensor S2. The bucket angle calculation unit 3008C calculates (measures) the bucket angle β3 based on the detection signal captured from the bucket angle sensor S3.

The control target speed calculation unit 3009 is configured to calculate a moving speed of the control target. In the illustrated example, the control target speed calculation unit 3009 is configured to calculate a moving speed of the claw tip of the bucket 6 as the control target moving along the target construction surface. Specifically, the control target speed calculation unit 3009 can derive the coordinates of the claw tip of the bucket 6 based on the outputs of the boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3, and information about the dimensions of the boom 4, the arm 5, and the bucket 6 set in advance. Then, the control target speed calculation unit 3009 can derive the moving speed of the claw tip of the bucket 6 at a second time point based on the coordinates of the claw tip of the bucket 6 at a first time point and the coordinates of the claw tip of the bucket 6 at the second time point, where the second time point is a time point when the unit time has elapsed from the first time point.

The restriction unit 3010 is configured to perform control to restrict the operation amount of the arm operation lever acquired (calculated) by the operation content acquisition unit 3001 (hereinafter, referred to as “calculated operation amount”) to a predetermined amount or less. In the illustrated example, the restriction unit 3010 is configured to output a predetermined amount that is smaller than the calculated operation amount to each of the target position calculation unit 3005 and the operation command generation unit 3006 when the calculated operation amount of the arm operation lever exceeds the predetermined amount. Further, the restriction unit 3010 is configured to output the calculated operation amount to each of the target position calculation unit 3005 and the operation command generation unit 3006 as it is when the calculated operation amount of the arm operation lever is the predetermined amount or less.

In the illustrated example, the predetermined amount is a value stored in advance in the internal memory, the external storage device, or the like. Specifically, the predetermined amount is a value determined according to the operation amount of the arm operation lever, and is set to increase as the operation amount of the arm operation lever increases. The restriction unit 3010 may calculate the predetermined amount corresponding to the operation amount of the arm operation lever using a map, an arithmetic expression, or the like stored in advance in the internal memory, the external storage device, or the like.

Specifically, the restriction unit 3010 is configured to determine whether to output the calculated operation amount of the arm operation lever by restricting the calculated operation amount to a predetermined amount or to output the calculated operation amount as it is, based on the moving speed of the control target calculated by the control target speed calculation unit 3009. In the illustrated example, the restriction unit 3010 is configured to restrict the calculated operation amount of the arm operation lever to a predetermined amount and output the restricted amount when the moving speed of the control target exceeds a predetermined speed.

When the calculated operation amount of the arm operation lever is restricted to a predetermined amount and output, control for restricting an opening or closing (rotation) speed of the arm 5 is performed. That is, the controller 30 can perform control of restricting the moving speed of the claw tip of the bucket 6 moving along the target construction surface by restricting the calculated operation amount of the arm operation lever to a predetermined amount and outputting the restricted amount.

With this configuration, for example, when the controller 30 moves the claw tip of the bucket 6 along the target construction surface including a slope portion and a horizontal surface portion, the controller 30 can make the moving speed of the claw tip moving along the slope portion equal to the moving speed of the claw tip moving along the horizontal surface portion provided that the operation amount of the arm operation lever is unchanged.

In the example illustrated in FIG. 6A, the restricting unit 3010 is disposed at a subsequent stage of the operation content acquisition unit 3001, but may be integrated with the action command generation unit 3006. In this case, the restriction unit 3010 may be configured to perform reduction adjustment of the arm command value β2r and perform increase/decrease adjustment of at least one of the boom command value β1r and the bucket command value β3r in accordance with the arm command value β2r that has been subjected to the reduction adjustment when the moving speed of the control target (the claw tip of the bucket 6) exceeds a predetermined speed.

Next, the effect of the restriction unit 3010 will be described with reference to FIG. 7. FIG. 7 is a schematic diagram illustrating the movement of the attachment AT of the excavator 100 when the control target CP is moved along a target construction surface TP which is an example of the target surface.

Specifically, in FIG. 7, the current state of the attachment AT is indicated by a solid line, and the state of the attachment AT after the elapse of a predetermined time is indicated by a dotted line. In the schematic diagram of FIG. 7, the boom 4, the arm 5, and the bucket 6 are represented by straight line segments, the upper slewing body 3 and the lower end of the boom 4 are connected by a boom foot pin 4F, the boom 4 and the arm 5 are connected by a boom top pin 4T, and the arm 5 and the bucket 6 are connected by an arm top pin 5T. The control target CP is the claw tip of the bucket 6.

More specifically, an upper diagram of FIG. 7 illustrates the movement of the attachment AT when the restriction by the restriction unit 3010 is not executed, and a lower diagram of FIG. 7 illustrates the movement of the attachment AT when the restriction by the restriction unit 3010 is executed. In the upper diagram of FIG. 7, a suffix “a” is added to the reference numeral of each element indicating the state of the attachment AT after the predetermined time has elapsed, as in “attachment ATa” for “attachment AT.” Similarly, in the lower diagram of FIG. 7, a suffix “b” is added to the reference numerals of the elements indicating the state of the attachment AT after the predetermined time has elapsed, as in “bucket 6b” for “bucket 6.” Further, the target construction surface TP indicated by a dash dot line in the upper drawing of FIG. 7 and the target construction surface TP indicated by the dash dot line in the lower drawing of FIG. 7 are the same, and include a gentle slope portion GP, a steep slope portion SP, and a horizontal surface portion HP.

In a case where the restriction by the restriction unit 3010 is not executed, when the arm operation lever is operated in the arm closing direction, the controller 30 moves the claw tip of the bucket 6 serving as the control target CP in the direction of the solid line arrow at the moving speed MV1 along the gentle slope portion GP of the target construction surface TP, as illustrated by the solid line in the upper drawing of FIG. 7. At this time, the controller 30 closes the arm 5 at the rotation speed AV1. The controller 30 automatically raises the boom 4 in response to the closing operation of the arm 5.

When the operation of the arm operation lever in the arm closing direction is continued with the same operation amount, the controller 30 moves the claw tip of the bucket 6a serving as the control target CPa in the direction of the dotted arrow at a moving speed MV1a along the steep slope portion SP of the target construction surface TP after the predetermined time has elapsed, as indicated by the dotted line in the upper drawing of FIG. 7. At this time, the controller 30 closes the arm 5 at the same rotation speed AV1 as the rotation speed AV1a. The controller 30 automatically raises the boom 4 in response to the closing operation of the arm 5.

In this manner, when the restriction by the restriction unit 3010 is not executed, the controller 30 adjusts the rotation speed of at least one of the boom 4 and the bucket 6 while maintaining the rotation speed AV1 of the arm 5 to align the claw tip of the bucket 6 with the target construction surface TP provided that the operation amount of the arm operation lever when moving the claw tip of the bucket 6 along the target construction surface TP is unchanged. Therefore, the controller 30 may excessively increase the moving speed MV1a of the control target CPa moving along the steep slope portion SP of the target construction surface TP.

Therefore, the controller 30 is configured to be able to prevent the rapid change in the moving speed MV1 of the control target CP by executing the restriction by the restriction unit 3010.

Specifically, even when the restriction is executed by the restriction unit 3010, the controller 30 moves the claw tip of the bucket 6 serving as the control target CP in the direction of the solid arrow at the moving speed MV1 along the gentle slope portion GP of the target construction surface TP as indicated by the solid line in the lower drawing of FIG. 7 when the arm operation lever is operated in the arm closing direction. At this time, the controller 30 closes the arm 5 at the rotation speed AV1. The controller 30 automatically raises the boom 4 in response to the closing operation of the arm 5.

When the operation of the arm operation lever in the arm closing direction is continued with the same operation amount, the controller 30 moves the claw tip of the bucket 6b serving as the control target CPb in the direction of the dotted arrow at a moving speed MV1b along the steep slope portion SP of the target construction surface TP after the predetermined time has elapsed, as illustrated by the dotted line in the lower drawing of FIG. 7.

When the moving speed MV1b of the claw tip of the bucket 6b exceeds a predetermined speed, the controller 30 restricts the operation of the arm 5. In the illustrated example, the predetermined speed is a moving speed MV1 of the control target CP moving along the gentle slope portion GP of the target construction surface TP. Specifically, the restriction unit 3010 of the controller 30 replaces the calculated operation amount of the arm operation lever with amount, and then outputs the replaced a predetermined amount to each of the target position predetermined calculation unit 3005 and the operation command generation unit 3006. As a result, the rotation speed AV1b of the arm 5 is restricted to be smaller than the rotation speed AV1, and the moving speed MV1b of the claw tip of the bucket 6b is also restricted to the predetermined speed.

As described above, when the operation amount of the arm operation lever is unchanged while the claw tip of the bucket 6 is moved along the target construction surface TP, the controller 30 adjusts the rotation speed of the arm 5 and the rotation speed of at least one of the boom 4 and the bucket 6 to match the claw tip of the bucket 6 with the target construction surface TP while maintaining the moving speed MV1 of the control target CP (claw tip of the bucket 6b) when the restricting unit 3010 performs the restricting operation. Therefore, the controller 30 can prevent the moving speed MV1b of the control target CPb moving along the steep slope portion SP of the target construction surface TP from becoming excessively high.

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 slewably mounted on the lower traveling body 1, the attachment AT including the boom 4, the arm 5, and the end attachment (bucket 6) attached to the upper slewing body 3, the arm operation lever (left operation lever 26L (see FIG. 3)) for operating the arm 5, and the control device (controller 30) configured to operate the arm 5 in accordance with the operation amount of the arm operation lever (left operation lever 26L) and operate at least one of the boom 4 and the end attachment (bucket 6) in accordance with the operation of the arm 5. As illustrated in FIG. 7, the control device (controller 30) is configured to restrict the operation of the arm 5 such that the moving speed MV1 of the control target CP, which is a predetermined part of the attachment AT, along the target surface (target construction surface TP) becomes a predetermined speed. Note that moving the predetermined work part while aligning the predetermined work part with the target surface means that the predetermined work part moves on the target surface. The target surface may be a surface (a surface other than the target construction surface TP) set based on the position of the target construction surface TP, or may be a surface set independently of the target construction surface TP. With this configuration, the excavator 100 can improve the operability of the attachment AT when the controller-responder control method is employed.

In the excavator 100, the control target CP may be a predetermined work part in the end attachment (bucket 6) or an arm top pin. The predetermined work part in the end attachment (bucket 6) may be the claw tip or the back surface of the bucket 6.

As illustrated in FIG. 3, the excavator 100 may include the main pump 14 mounted on the upper slewing body 3, a pilot pump 15 mounted on the upper slewing body 3, an arm cylinder control valve (control valve 176) provided in a hydraulic fluid line connecting the arm cylinder 8 and the main pump 14, and an arm solenoid valve (solenoid valve 31AL, solenoid valve 31AR (see FIG. 4A)) provided in a pilot line connecting pilot port of the arm cylinder control valve (control valve 176) and the pilot pump 15. The control device (controller 30) may be configured to restrict the operation speed of the arm 5 by adjusting a value of a control command output to the arm solenoid valve (solenoid valves 31AL and 31AR) to adjust the pilot pressure acting on the pilot port of the arm cylinder control valve (control valve 176).

In addition, as illustrated in FIG. 7, the excavator 100 may be configured such that the moving speed MV1 of the control target CP along the target surface (target construction surface TP) changes in accordance with the operation amount of the arm operation lever (left operation lever 26L). For example, the moving speed MV1 of the control target CP along the target surface (target construction surface TP) may be configured to increase as the operation amount of the arm operation lever (left operation lever 26L) increases.

Further, the target surface (target construction surface TP) may include the steep slope portion SP and the gentle slope portion GP or a horizontal surface portion HP as illustrated in FIG. 7. In this case, the control device (controller 30) may be configured to operate the arm 5 such that the moving speed MV1 of the control target CP when moving the work part (claw tip of the bucket 6) while aligning the work part with the gentle slope portion GP or the horizontal surface portion HP is the same as the moving speed MV1b of the control target CPb when moving the work part (claw tip of the bucket 6) while aligning the work part with the steep slope portion SP, as illustrated in the lower drawing of FIG. 7, provided that the operation amount of the arm operation lever (left operation lever 26L) is the same. This configuration can prevent the operator of the excavator from feeling “difficult to operate.” This is because it is possible to prevent the occurrence of a situation in which the moving speed MV1 of the control target CP suddenly changes even though the operation amount of the arm operation lever is unchanged.

In the example as illustrated in FIG. 7, the work part may include a first work part (for example, the claw tip of the bucket 6) that comes into contact with the gentle slope portion GP or the horizontal surface portion HP and a second work part (for example, the back surface of the bucket 6) that comes into contact with the steep slope portion SP. For example, after moving the bucket 6 while aligning the claw tip of the bucket 6 with the gentle slope portion GP, the controller 30 may move the bucket 6 while aligning the back surface of the bucket 6 with the steep slope portion SP, and may further move the bucket 6 while aligning the claw tip of the bucket 6 with the horizontal surface portion HP.

The restriction by the restriction unit 3010 described above is applied when the bucket 6 is moved along the target construction surface TP including a downward slope portion, but may be applied when the bucket 6 is moved along the target construction surface TP including an upward slope portion.

Another Embodiment

In the above-described embodiment, an example has been described in which the speed of the work part is controlled by the restriction unit 3010 restricting the operation amount of the arm operation lever acquired by the operation content acquisition unit 3001 to a predetermined amount or less. However, the above-described embodiment merely illustrates an example of a method of controlling the speed of the work part, and other methods may be used. Therefore, in another embodiment, another method of controlling the speed of the work part will be described.

The excavator 100 according to the present embodiment is an example in which a controller 30A that performs different processing is provided instead of the controller 30. Other configurations are the same as those of the above-described embodiment, and thus the description thereof will be omitted.

FIG. 8 is a schematic diagram illustrating speed control of the work part performed by the controller 30A according to the present embodiment. In the example illustrated in FIG. 8, the claw tip of the bucket 6 moves along the target construction surface. The t target construction surface includes a first construction surface (an example of a first target surface, angle θ_slope1) and a second construction surface (an example of a second target surface, angle θ_slope2). The claw tip of the bucket 6 is controlled so as to move along the first construction surface (angle θ_slope1) and subsequently move along the second construction surface (angle θ_slope2). The first construction surface (angle θ_slope1) is a horizontal surface substantially parallel to the ground plane of the excavator 100, and the second construction surface (angle θ_slope1) is a slope inclined downward (angle θ_slope1>10 degrees at least in a height direction).

When the claw tip of the bucket 6 is moved along the first construction surface (angle θ_slope1), the moving speed of the claw tip of the bucket 6 is mainly based on the angular velocity ω_arm of the arm 5. The movement of the boom 4 is only adjusted such that the claw tip of the bucket 6 moves along the first construction surface (angle θ_slope1).

When the surface on which the claw tip of the bucket 6 moves is switched from the first construction surface (angle θ_slope1) to the second construction surface (angle θ_slope2), a large movement control of boom 4 in addition to the arm 5 is required.

In the conventional semi-automatic control, the boom cylinder 7 is largely operated in addition to the arm cylinder 8 so as to move the claw tip of the bucket 6 along the second construction surface (angle θ_slope2). Accordingly, the claw tip of the bucket can be moved along the second construction surface (angle θ_slope2).

In such a conventional semi-automatic control, control is performed to output the angular velocity ω_boom of the boom in a state where the angular velocity ω_arm of the arm when the claw tip of the bucket moves on the first construction surface (angle θ_slope1) is maintained. Therefore, the claw tip of the bucket rises from the moving speed Vt1 to the moving speed Vt2. This is because when the arm moves at a constant speed and the operation is switched from movement on the horizontal surface to movement along a slope having an angle relative to the horizontal surface, the amount of movement in the up-down direction is large, resulting in a large boom movement. That is, in the conventional semi-automatic control, there is a possibility that rapid acceleration occurs at the claw tip of the bucket.

In contrast, the controller 30A of the excavator 100 according to the present embodiment controls the boom cylinder 7 and the arm cylinder 8 such that the moving speed of the claw tip of the bucket corresponds to an operation amount in response to reception of an operation on the arm 5. When the controller 30A moves the claw tip of the bucket 6 (an example of a predetermined work part) while aligning the claw tip of the bucket 6 with the construction surface (an example of a target surface) in accordance with the operation, the controller 30A controls the operation of at least one of the arm 5 and the boom 4 such that the moving speed of the claw tip of the bucket 6 is the same when a surface with which the claw tip of the bucket 6 is to be aligned changes from the first construction surface (angle @slope1) to the second construction surface (angle θ_slope2). In the present embodiment, an example of adjusting the operation of the arm 5 as the controller element will be described. Note that, in this embodiment, an example will be described in which the boom cylinder 7 and the arm cylinder 8 are used as a plurality of hydraulic actuators that operate the attachment, but this embodiment does not limit the types of the plurality of hydraulic actuators that operate the attachment, and other configurations may also be used.

FIG. 9 is a diagram illustrating a change in the speed of the claw tip of the bucket 6 corresponding to the arm operation by the operator in the excavator 100 according to the present embodiment. The first construction surface and the second construction surface illustrated in FIG. 9 are similar to those illustrated in FIG. 8, and thus the description thereof will be omitted.

In the example illustrated in FIG. 9, a change 1901 in the speed of the claw tip of the bucket 6, a change 1902 in the angular velocity of the arm 5, and a change 1903 in the pilot pressure acting on the pilot port of the arm cylinder control valve are illustrated.

The example illustrated in FIG. 9 indicates a case in which the operator operates the left operation lever 26L in the arm closing direction at time to. In the present embodiment, the controller 30A controls the claw tip of the bucket 6, in accordance with data about the target construction surface stored in the excavator 100 (not illustrated), such that after the claw tip of the bucket 6 is moved along the first construction surface, the claw tip of the bucket 6 is moved along the second construction surface.

In the example illustrated in FIG. 9, after the operation is started at time to, the pilot pressure acting on the pilot port of the arm cylinder control valve reaches a pressure Pi1 at time t1. Accordingly, the angular velocity of the arm 5 also reaches the angular velocity ω_arm1. Accordingly, the claw tip of the bucket 6 reaches the moving speed Vt1.

At the time t2, the surface with which the claw tip of the bucket 6 is to be aligned changes from the first construction surface (angle θ_slope1) to the second construction surface (angle θ_slope2). Conventionally, as illustrated by line 1931, the pilot pressure acting on the pilot port of the arm cylinder control valve is maintained at the pressure Pi1. Therefore, as indicated by the line 1921, the angular velocity ω_arm1 is maintained as the angular velocity of the arm 5. In this case, the angular velocity ω_boom1 of the boom 4 is added in accordance with the change in the surface with which the claw tip of the bucket 6 is to be aligned. Therefore, as illustrated by the line 1911, the moving speed of the claw tip of the bucket 6 changes to the moving speed Vt2, and thus rapid acceleration occurs.

Therefore, the controller 30A according to the present embodiment performs control to switch the pilot pressure acting on the pilot port of the arm cylinder control valve from the pressure Pi1 to a pressure Pi2 as indicated by the line 1932 when the surface with which the claw tip of the bucket 6 is to be aligned changes from the first construction surface (angle θ_slope1) to the second construction surface (angle θ_slope2) at time t2.

Since the pilot pressure has been switched to the pressure Pi2, the angular velocity of the arm 5 also decreases from the angular velocity ω_arm to the angular velocity ω_arm2, as indicated by the line 1922. At time t2, the angular velocity ω_boom2 of the boom 4 is added in accordance with a change in the surface with which the claw tip of the bucket 6 is to be aligned. That is, the controller 30A controls the arm cylinder 8 so as to reduce the angular velocity of the arm 5, and controls the boom cylinder 7 so as to increase the angular velocity of the boom 4, and thus, as indicated by the line 1912, the claw tip of the bucket 6 is maintained at the moving speed Vt1.

In the present embodiment, the controller 30A adjusts the pilot pressure acting on the pilot port of the arm cylinder control valve in accordance with the change in the surface on which the claw tip of the bucket 6 moves, thereby performing control such that the moving speed of the claw tip of the bucket 6 is the same. Therefore, it is possible to prevent the occurrence of rapid acceleration at the claw tip of the bucket 6. A specific method of adjusting the pilot pressure will be described later.

Next, an example of a detailed configuration related to the machine control function will be described with reference to FIGS. 10A and 10B. FIG. 10A and FIG. 10B are diagrams illustrating configuration examples of the controller 30A. In particular, FIGS. 10A and 10B illustrate an example of a detailed configuration of the machine control function. The following description with reference to FIGS. 10A and 10B relates to a machine control function executed when the left operation lever 26L (arm operation lever) for moving the arm 5 is operated in a state where the switch SW is operated.

The controller 30A includes, as functional units related to the machine control function, an operation content acquisition unit target 3001, a construction surface acquisition unit 3002, a target trajectory setting unit 3003, a current position calculating unit 3004, a target position calculation unit 3005, an operation command generation unit 3006, a pilot command generation unit 3007, a posture angle calculating unit 3008, a boom pilot command adjustment unit 3107A, and an arm pilot command adjustment unit 3107B. In the illustrated example, each of the functional units of the controller 30A is implemented by software. However, each of the functional units of the controller 30A may be implemented by hardware (electronic circuit or the like) or may be implemented by a combination of software and hardware. In the illustrated example, each of the functional units of the controller 30A repeatedly executes processing described later at predetermined control intervals when the switch SW is operated. Note that the same symbols are assigned to the same components as those of the functional units illustrated in FIG. 10A and FIG. 10B, and the description thereof will be omitted, in each of the functional units of the controller 30A illustrated in FIG. 6A and FIG. 6B.

The controller 30A according to the present embodiment is differing from the controller 30 in that the boom pilot command adjustment unit 3107A and the arm pilot command adjustment unit 3107B are added, but the control target speed calculation unit 3009 and the restriction unit 3010 are deleted.

Thus, the operation command generation unit 3006 generates a command value related to the motion of the work element in accordance with the calculated amount of operation of the arm operation lever without the calculated amount of operation of the arm operation lever being restricted to a predetermined amount by the restriction unit 3010 as in the embodiment. Specifically, the controller command generation unit 3006A generates the arm command value β2r based on a predetermined map or conversion formula that defines the relationship between the operation content of the arm operation lever and the arm command value β2r, and the responder command generation unit 3006B generates the boom command value β2r and the bucket command value β1r such that at least one of the boom 4 and the bucket 6 operates in accordance with (in synchronization with) the operation of the arm 5 corresponding to the arm command value β3r, and the control target of the bucket 6 can reach the target position (that is, move along the target construction surface).

Then, the pilot command generation unit 3007 generates a command value of the pilot pressure (hereinafter, referred to as a “pilot pressure command value”) to be applied to each of the control valves 174 to 176 in order to achieve the boom angle, the arm angle, and the bucket angle corresponding to the boom command value β1r, the arm command value β2r, and the bucket command value β3r. The pilot command generation unit 3007 includes the boom pilot command generation unit 3007A, an arm pilot command generation unit 3007B, and a bucket pilot command generation unit 3007C. The processing performed by the boom pilot command generation unit 3007A, the arm pilot command generation unit 3007B, and the bucket pilot command generation unit 3007C is the same as that in the above-described embodiment.

The boom pilot command adjustment unit 3107A and the arm pilot command adjustment unit 3107B adjust the pilot pressure command value such that when the left operation lever 26L (arm operation lever) for moving the arm 5 is operated with the switch SW operated, the moving speed of the claw tip of the bucket 6 is maintained even when the angle of the target construction surface changes.

Next, the pilot pressure command value adjusted to maintain the moving speed Vt of the claw tip of the bucket 6 will be described. In the present embodiment, the pilot pressure command value is adjusted such that the moving speed Vt is substantially the same.

The moving speed Vt of the claw tip of the bucket 6 is a first order differential of the claw tip coordinates (x(θ_b, θ_a), y(θ_b, θ_a)). The function x is a function for calculating the position of the x coordinate of the claw tip of the bucket 6 based on the angle θ_b of the boom 4 and the angle θ_a of the arm 5. The function y is a function for calculating the position of the y coordinate of the claw tip of the bucket 6 based on the angle θ_b of the boom 4 and the angle θ_a of the arm 5.

A differential value of the angle θ_b of the boom 4 is represented as an angular velocity ω_boom, and a differential value of the angle θ_a of the arm 5 is represented as an angular velocity ω_arm. The moving speed Vt can be calculated by a first order differential of the claw tip coordinates (x(θ_b, θ_a), y(θ_b, θ_a)), in other words, by an operation using the angular velocity ω_boom, the angular velocity ω_arm, the angle θ_b of the boom 4, and the angle θ_a of the arm 5. When the claw tip of the bucket 6 moves on the construction surface of the angle θ_slope, the angular velocity ω_boom is determined according to the angle θ_b of the boom 4, the angle θ_a of the arm 5, the angular velocity ω_arm, and the angle θ_slope. That is, the moving speed Vt can be derived from the angle θ_slope, the angular velocity ω_arm, the angle θ_b of the boom 4, and the angle θ_a of the arm 5.

When the construction surface changes from the angle θ_slope1 to the angle θ_slope2, the angular velocity of the arm 5 when moving the claw tip of the bucket 6 along the angle θ_slope1 is ω_arm1, and the angular velocity of the arm 5 when moving the claw tip of the bucket 6 along the angle θ_slope2 is ω_arm2.

When the construction surface changes from the angle θ_slope1 to the angle θ_slope2, the angular velocity ω_arm2 of the arm 5 for making the moving speed Vt substantially the same can be derived from the angle θ_slope1, the angle θ_slope2, and the angular velocity ω_arm1 of the arm 5 in consideration of the above-described calculation. At the time when the angle of the construction surface is changed, the angle θ_b of the boom 4 and the angle θ_a of the arm 5 become substantially the same, and thus can be omitted.

There is a correspondence between the angular velocity ω_arm of the arm 5 and the opening surface of the solenoid valve 31 that controls the arm cylinder 8. Therefore, when the angle of the construction surface changes, the controller 30A performs control such that the solenoid valve 31 for controlling the arm cylinder 8 has an opening area A_PC2 corresponding to the derived angular velocity ω_arm2 of the arm 5, whereby the moving speed Vt is maintained to be substantially the same. The arm pilot command adjustment unit 3107B holds opening diagram information (not illustrated). The opening diagram information is information that holds a correspondence between the opening area and the pilot pressure.

Then, when the construction surface changes from the angle θ_slope1 to the angle θ_slope2, the arm pilot command adjustment unit 3107B calculates and outputs a pilot pressure command value Pi_arm2 corresponding to the opening area A_PC2 based on the opening diagram information. Whether or not the construction surface has changed from the angle θ_slope1 to the angle θ_slope2 can be specified from the information input from the target construction surface acquisition unit 3002 and the calculation results of the boom angle calculation unit 3008A and the arm angle calculating unit 3008B. In the present embodiment, the adjustment may be started at a timing before a predetermined control cycle, instead of starting the adjustment at the timing when the angle θ_slope1 changes to the angle θ_slope2.

Further, since the pilot pressure of the arm 5 is adjusted, the pilot pressure of the boom 4 also needs to be adjusted. The pilot pressure of the boom 4 may be adjusted according to an adjustment ratio of the pilot pressure of the arm 5.

Therefore, the arm pilot command adjustment unit 3107B calculates the adjustment ratio of the pilot pressure based on the calculated pilot pressure command value Pi_arm2 and the pilot pressure command value Pi_arm1 input from the arm pilot command generation unit 3007B, and outputs the adjustment ratio to the boom pilot command adjustment unit 3107A.

The boom pilot command adjustment unit 3107A adjusts the pilot pressure command value Pi_boom1 input from the boom pilot command generation unit 3007A according to the input adjustment ratio, and outputs the adjusted command value Pi_boom2. Since the pilot pressure of the arm 5 and the pilot pressure of the boom 4 are adjusted at the same adjustment ratio, the claw tip of the bucket 6 can be controlled to be along the construction surface.

As described above, since the pilot pressure command value Pi_arm2 of the arm 5 and the pilot pressure command value Pi_boom2 of the boom 4, which are adjusted in accordance with a change in the angle θ_slope2 of the construction surface, are output, the moving speed |Vt| of the claw tip of the bucket 6 can be maintained.

FIG. 11 is a diagram illustrating a movement route of the claw tip of the bucket 6 according to the present embodiment. In the example illustrated in FIG. 11, the controller 30A performs control so as to move the claw tip of the bucket 6 along the target construction surface TP.

The target construction surface TP includes a first construction surface TP11, a second construction surface TP12, a third construction surface TP13, a fourth construction surface TP14, and a fifth construction surface TP15.

The first construction surface TP11, the third construction surface TP13, and the fifth construction surface TP15 are substantially horizontal surfaces. The second construction surface TP12 is a surface inclined upward by an angle β1 with respect to the horizontal surface RP. The fourth construction surface TP14 is a surface inclined downward by an angle β2 with respect to the horizontal surface RP.

Then, the controller 30A performs control such that the moving speed of the claw tip of the bucket 6 is maintained substantially constant independent of the angle of the target construction surface TP.

Specifically, when the claw tip of the bucket 6 is moving along the first construction surface TP11, the moving speed of the claw tip of the bucket 6 (6A) is set to the moving speed Vt.

Then, when the claw tip of the bucket 6 reaches the slope foot P11, the pilot pressure is adjusted by the arm pilot command adjustment unit 3107B and the boom pilot command adjustment unit 3107A in accordance with the angle 31 of the second construction surface TP12. Thus, the moving speed Vt of the claw tip of the bucket 6 (6B) is maintained. That is, the controller 30A controls the arm cylinder 8 so as to reduce the angular velocity of the arm 5, and controls the boom cylinder 7 so as to increase the angular velocity of the boom 4.

When the claw tip of the bucket 6 reaches the slope shoulder P12, the adjustment of the pilot pressure by the arm pilot command adjustment unit 3107B and the boom pilot command adjustment unit 3107A is cancelled. Therefore, the moving speed Vt of the claw tip of the bucket 6 (6C) is maintained. That is, the controller 30A controls the arm cylinder 8 so as to increase the angular velocity of the arm 5. On the other hand, since the movement of the boom 4 is restricted on the horizontal surface, the controller 30A controls the boom cylinder 7 so as to reduce the angular velocity of the boom 4.

Thereafter, when the claw tip of the bucket 6 reaches the slope shoulder P13, the pilot pressure is adjusted by the arm pilot command adjustment unit 3107B and the boom pilot command adjustment unit 3107A in accordance with the angle β2 of the fourth construction surface TP14. Thus, the moving speed Vt of the claw tip of the bucket 6 (6D) is maintained. That is, the controller 30A controls the arm cylinder 8 so as to reduce the angular velocity of the arm 5, and controls the boom cylinder 7 so as to increase the angular velocity of the boom 4.

Thereafter, when the claw tip of the bucket 6 reaches the slope foot P14, the adjustment of the pilot pressure by the arm pilot command adjustment unit 3107B and the boom pilot command adjustment unit 3107A is cancelled. Thus, the moving speed Vt of the claw tip of the bucket 6 (6E) is maintained. That is, the controller 30A controls the arm cylinder 8 so as to increase the angular velocity of the arm 5 and controls the boom cylinder 7 so as to decrease the angular velocity of the boom 4.

Thereafter, the moving speed Vt of the claw tip of the bucket 6 (6F) is maintained until the end of the construction.

The controller 3 to the present embodiment has the above-described configuration, and thus can maintain the moving speed of the claw tip of the bucket 6 substantially constant even when a combined surface of a horizontal surface and a slope is constructed. Therefore, when the construction is switched from the horizontal surface to the slope, the rapid acceleration of the claw tip of the bucket 6 based on the operation of the boom 4 can be prevented.

When the arm operation is performed, the controller 30A according to the present embodiment controls the boom cylinder 7 and the arm cylinder 8 so as to move the claw tip of the bucket 6 along the construction surface based on the height and the angle of the construction surface indicated by data on the target construction surface.

Then, the controller 30A predicts a timing at which the claw tip of the bucket 6 performs construction on the slope from construction information, and the arm pilot command adjustment unit 3107B starts adjustment of the pilot pressure at a timing of predetermined control cycles before the predicted timing. Accordingly, the boom pilot command adjustment unit 3107A also adjusts the pilot pressure. Therefore, the moving speed of the claw tip of the bucket 6 is maintained. In the present embodiment, an example of controlling the moving speed Vt of the claw tip to be maintained has been described.

The controller 30A according to the present embodiment may switch whether or not to adjust the pilot pressure by the arm pilot command adjustment unit 3107B and the boom pilot command adjustment unit 3107A, in accordance with the angle of the construction surface. For example, when the construction surface has a slope of 10 degrees or more, adjustment of the pilot pressure by the arm pilot command adjustment unit 3107B and the boom pilot command adjustment unit 3107A may be started, and when the construction surface is substantially horizontal, adjustment of the pilot pressure may be cancelled. In this manner, in the present embodiment, even when the angle of the construction surface changes in any manner, the moving speed of the claw tip of the bucket 6 can be maintained.

In the present embodiment, an example in which the pilot pressure command value of the arm 5 and the pilot pressure command value the boom 4 are adjusted has been described. However, in the present embodiment, the adjustment target is not limited to the boom 4 and the arm 5. For example, the control of the boom 4, the arm 5, and the bucket 6 may be combined to control the bucket 6 such that the moving speed of the claw tip of the bucket 6 is maintained.

The control described in the present embodiment is an example, and it is not necessary to strictly match the moving speed Vt of the claw tip before and after the change in the angle of the construction surface. That is, the controller 30A may adjust the moving speed to such a degree that the operator does not feel discomfort, in other words, to such a degree that the operator feels that the moving speed is substantially the same.

In the present embodiment, the pilot pressure is adjusted such that the moving speed Vt of the claw tip of the bucket 6 corresponding to the operation amount of the arm operation is maintained. In other words, when the operation amount of the arm operation lever is changed, the moving speed of the claw tip of the bucket 6 is adjusted to a moving speed corresponding to the changed operation amount. Therefore, the operator can perform control so as to move the claw tip of the bucket 6 at a desired moving speed independent of the angle of the construction surface, and thus, improvement in operability can be obtained.

In the present embodiment, the case where the moving speed Vt of the claw tip of the bucket 6 is maintained in accordance with the operation amount of the arm operation has been described. However, in the present embodiment, the operation in which the moving speed Vt is maintained is not limited to the arm operation, and may be, for example, a boom operation or the like.

Furthermore, in this embodiment, the opening area is adjusted by the arm pilot command adjustment unit 3107B and the boom pilot command adjustment unit 3107A at a magnification corresponding to the amount of change in the angle of the construction surface, making control easy and reducing the processing burden.

In the above-described embodiment, the excavator 100 has the above-described configuration, which enables preventing the occurrence of rapid acceleration in the work part of the bucket 6 when the angle of the target construction surface is switched. Therefore, the operator is prevented from feeling discomfort in the operation, and the operability is improved. Furthermore, in the above-described embodiment, since rapid acceleration or the like is prevented, safety can be improved.

In the above-described embodiment, the controller element is the arm 5, and the controller operation lever is the arm operation lever. However, the controller element may be the boom 4, and the controller operation lever may be the boom operation lever. In this case, the restriction unit 3010 may be configured to restrict the rotation speed of the boom 4 when the target construction surface is switched from the downward slope portion to the horizontal surface portion, for example.

The excavator 100 may be a remote control excavator or an unmanned (autonomous) excavator.

The preferred embodiments of the present disclosure have been described in detail above. However, the present disclosure is not limited to the above-described embodiments. Various modifications, substitutions, and the like can be applied to the above-described embodiment without departing from the scope of the present disclosure. Also, features that have been described separately can be combined as long as no technical contradiction arises.

Claims

1. A control device for an excavator, the excavator including a lower traveling body; an upper slewing body slewably mounted on the lower traveling body; and an attachment attached to the upper slewing body, the attachment including a boom, an arm, and an end attachment, the control device comprising: circuitry configured to operate the arm in response to a command value so as to move a predetermined work part of the end attachment while aligning the predetermined work part with a target surface, and to operate at least one of the boom or the end attachment in accordance with the operation of the arm,wherein the circuitry controls the operation of at least one of the arm or the boom such that a moving speed of a control target along the target surface becomes a predetermined speed, the control target being a predetermined part of the attachment, andwherein in a case where the target surface includes a steep slope portion, and a gentle slope portion or a horizontal surface portion, and provided that an operation amount of an arm operation lever is same for both portions, the circuitry operates the arm such that a moving speed of the control target when moving the predetermined work part while aligning the predetermined work part with the gentle slope portion or the horizontal surface portion is same as a moving speed of the control target when moving the predetermined work part while aligning the predetermined work part with the steep slope portion.

2. The control device for an excavator according to claim 1, wherein the control target is the predetermined work part of the end attachment or an arm top pin.

3. The control device for an excavator according to claim 1, wherein the excavator further includes: a main pump mounted in the upper slewing body;a pilot pump mounted in the upper slewing body;an arm cylinder control valve provided in a hydraulic fluid line connecting an arm cylinder and the main pump; andan arm solenoid valve provided in a pilot line connecting a pilot port of the arm cylinder control valve and the pilot pump,wherein the circuitry restricts an operation speed of the arm by adjusting a value of a control command output to the arm solenoid valve to adjust a pilot pressure acting on the pilot port of the arm cylinder control valve.

4. The control device for an excavator according to claim 1, wherein the moving speed of the control target along the target surface changes in accordance with the operation amount of the arm operation lever.

5. The control device for an excavator according to claim 1, wherein the predetermined work part includes: a first work part that is aligned with the gentle slope portion or the horizontal surface portion, anda second work part that is aligned with the steep slope portion.

6. A control device for an excavator, the excavator including a lower traveling body; an upper slewing body slewably mounted on the lower traveling body; and an attachment attached to the upper slewing body, the attachment including a boom, an arm, and an end attachment, the control device comprising: circuitry configured to operate a controller element in response to a command value so as to move a predetermined work part of the end attachment while aligning the predetermined work part with a target surface, and to operate one or a plurality of responder elements in accordance with the operation of the controller element,wherein the circuitry restricts the operation of at least one of the controller element or the responder elements such that a moving speed of a control target along the target surface becomes a predetermined speed, the control target being a predetermined part of the attachment, andwherein in a case where the target surface includes a steep slope portion, and a gentle slope portion or a horizontal surface portion, and provided that an operation amount of an arm operation lever is same for both portions, the circuitry operates the controller element such that a moving speed of the control target when moving the predetermined work part while aligning the predetermined work part with the gentle slope portion or the horizontal surface portion is same as a moving speed of the control target when moving the predetermined work part while aligning the predetermined work part with the steep slope portion.

7. A control device for an excavator, the excavator including a lower traveling body; an upper slewing body slewably mounted on the lower traveling body; and an attachment attached to the upper slewing body, the attachment including a boom, an arm, and an end attachment, the control device comprising: circuitry configured to operate the arm such that a moving speed of a predetermined work part of the end attachment is substantially same when a surface with which the predetermined work part is to be aligned changes between a substantially horizontal surface portion and a steep slope portion having an angle in a height direction relative to the substantially horizontal surface portion while moving the predetermined work part along a target surface, and also operate at least one of the boom or the end attachment in accordance with the operation of the arm.

8. The control device for an excavator according to claim 7, wherein in response to reception of an operation on the attachment, the circuitry operates the arm such that the moving speed of the predetermined work part corresponds to an operation amount of the received operation while moving the predetermined work part along the target surface, and also operates at least one of the boom or the end attachment in accordance with the operation of the arm.

9. The control device for an excavator according to claim 8, wherein in response to reception of an operation on the arm, the circuitry performs control to reduce an angular velocity of at least one of the arm or the boom such that the moving speed of the predetermined work part is substantially same when the surface with which the predetermined work part is to be aligned changes between the substantially horizontal surface portion and the steep slope portion while moving the predetermined work part along the target surface.

10. The control device for an excavator according to claim 9, wherein the circuitry, after moving the predetermined work part while aligning the predetermined work part with the substantially horizontal surface portion, performs control to reduce the angular velocity of the arm when moving the predetermined work part while aligning the predetermined work part with the steep slope portion.