EXCAVATOR

Abstract

An excavator includes: a lower traveling body; an upper rotating body that is rotatably mounted on the lower traveling body; an attachment that is attached to the upper rotating body, and includes a boom, an arm, and a bucket; and a controller that is configured to set a target surface, the target surface being set differently depending on a current angle of the bucket serving as a reference angle in setting the target surface.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority to Japanese Patent Application No. 2023-044478, filed on Mar. 20, 2023, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an excavator.

2. Description of the Related Art

Conventionally, there is an excavator that sets an approximate surface in a position that is closer to the surface of the ground than to the target digging surface, compares the height of the working part of an end attachment with the height of the approximate surface, and, based on comparison results, provides guidance to the operator by producing notification sounds.

SUMMARY OF THE INVENTION

Technical Problem

According to the conventional technique described above, it is necessary to set a target digging surface, an approximate surface, and so forth first, before starting the work with the excavator, and such configuration procedures consume time and resources.

In view of the above technical problem, an object of the present invention is to save the time and resources required for configuration procedures.

Solution to Problem

In order to achieve the above object, according to an embodiment of the present disclosure, an excavator includes: a lower traveling body; an upper rotating body that is rotatably mounted on the lower traveling body; an attachment that is attached to the upper rotating body, and includes a boom, an arm, and a bucket; and a controller that is configured to set a target surface, the target surface being set differently depending on a current angle of the bucket serving as a reference angle in setting the target surface.

Advantageous Effects of the Invention

The present invention can save the time and resources required for configuration procedures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an excavator;

FIG. 2 is a top view of the excavator;

FIG. 3 is a diagram that shows an example structure of the excavator's hydraulic system;

FIG. 4A is a diagram that extracts a part of the hydraulic system that relates to the operation of an arm cylinder;

FIG. 4B is a diagram that extracts a part of the hydraulic system that relates to the operation of a boom cylinder;

FIG. 4C is a diagram that extracts a part of the hydraulic system that relates to the operation of a bucket cylinder;

FIG. 4D is a diagram that extracts a part of the hydraulic system that relates to the operation of a rotary hydraulic motor;

FIG. 5 is a block diagram that shows an example structure related to a machine guidance function and a machine control function of the excavator;

FIG. 6A is a first functional block diagram that shows a detailed structure related to a semi-automatic driving function of the excavator;

FIG. 6B is a second functional block diagram that shows a detailed structure related to the semi-automatic driving function of the excavator;

FIG. 7 is a diagram that explains a target surface;

FIG. 8 is a diagram that shows an example of a target surface setting screen;

FIG. 9 is a diagram that explains an example of display on a display device; and

FIG. 10 is a diagram that explains changes of the target surface.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention (hereinafter “present embodiment”) will be described below with reference to the accompanying drawings. First, an overview of an excavator 100 according to the present embodiment will be described with reference to FIG. 1 and FIG. 2.

FIG. 1 and FIG. 2 are a top view and a side view, respectively, of the excavator 100 according to the present embodiment.

The excavator 100 according to the present embodiment includes: a lower traveling body 1; an upper rotating body 3 that is rotatably mounted on the lower traveling body 1 via a rotating mechanism 2; an attachment AT constituted by a boom 4, an arm 5, and a bucket 6; and a cabin 10.

As will be described below, the lower traveling body 1 (an example of a traveling body) includes a pair of left and right crawlers 1C, namely a left crawler 1CL and a right crawler 1CR. In the lower traveling body 1, the left crawler 1CL and the right crawler 1CR are hydraulically driven by traveling hydraulic motors 2M (2ML and 2MR), thereby allowing the excavator 100 to travel.

The upper rotating body 3 (an example of a rotating body) is driven by a rotary hydraulic motor 2A, and rotates relative to the lower traveling body 1.

The boom 4 is pivotally attached to the front center of the upper rotating body 3 such that the boom 4 can look up and down. At the tip of the boom 4, the arm 5 is pivotally attached such that the arm 5 can move upward and downward in a rotary motion. The bucket 6 that serves as an end attachment is pivotally attached to the tip of the arm 5 such that the bucket 6 can move upward and downward in a rotary motion. The boom 4, the arm 5, and the bucket 6 are hydraulically driven, respectively, by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, which serve as hydraulic actuators.

Note that the bucket 6 is an example of an end attachment, and a different end attachment, such as a slope bucket, a dredging bucket, a breaker, and the like may be attached to the tip of the arm 5, instead of the bucket 6, depending on the details of work.

The cabin 10 is the driver's room where the operator boards, and is mounted on the front left side of the upper rotating body 3.

The excavator 100 runs the actuators in accordance with operations by the operator in the cabin 10, and drives the moving elements (driven elements) such as the lower traveling body 1, upper rotating body 3, boom 4, arm 5, and bucket 6.

Also, although the excavator 100 is structured such that the operator in the cabin 10 can operate it, instead of or in addition to this, the excavator 100 may be structured such that it can be operated remotely by the operator of a predetermined external device (for example, an assisting device or a managing device).

In this case, the excavator 100 transmits, for example, image information (captured images) output by a space recognition device 70, which will be described later, to the external device. Also, images pertaining to a variety of information (for example, various configuration screens) displayed on a display device D1 of the excavator 100, which will be described later, may be similarly displayed on a display device provided in the external device.

By this means, the operator can remotely operate the excavator 100 while checking the contents displayed on the display device provided in the external device, for example. Then, the excavator 100 may run the actuators in accordance with remote operation signals that the excavator 100 receives from the external device, and that represent the details of remote operation, and drive the moving elements such as the lower traveling body 1, upper rotating body 3, boom 4, arm 5, and bucket 6.

When the excavator 100 is operated remotely, the cabin may be unmanned. The following description will be given on the premise that the operation by the operator refers to at least one of operation that the operator in the cabin 10 makes to the operating devices 26 and remote operation that the operator of an external device makes.

Also, the excavator 100 may run the hydraulic actuators automatically, regardless of the details of operation by the operator. By this means, the excavator 100 implements a function to allow at least some of the moving elements such as the lower traveling body 1, upper rotating body 3, boom 4, arm 5, and bucket 6, to move automatically (hereinafter referred to as “automatic driving function” or “machine control function”).

The automatic driving function may include a function (referred to as “semi-automatic driving function”) to allow moving elements (hydraulic actuators) other than the moving element (hydraulic actuator) that is being or targeted to be operated, to move automatically in accordance with the operator's operation of the operating devices 26 or remote operation. Also, the automatic driving function may include a function (referred to as “fully-automatic driving function”) to allow at least part of the driven elements (hydraulic actuators) to run automatically, on the premise that the operating devices 26 are not operated or remotely operated by the operator.

In the excavator 100, when the fully-automatic driving function is enabled, the cabin 10 may be unmanned. Also, the automatic driving function may include a function (“gesture operation function”) to allow the excavator 100 to recognize the gestures of people around the excavator 100 such as workers, and enable at least part of the driven elements (hydraulic actuators) to run automatically depending on the details of the recognized gestures.

Also, the semi-automatic driving function, the fully-automatic driving function, and the gesture operation function may include a mode in which the details of movement of the moving element (hydraulic actuator) subject to automatic driving are determined automatically according to rules determined in advance. Also, the semi-automatic driving function, the fully-automatic driving function, and the gesture operation function may include a mode (referred to as “autonomous driving function”), in which the excavator 100 autonomously makes various decisions, and in which, based on these decisions, the excavator 100 autonomously determines the details of the movement of the moving element (hydraulic actuator) subject to automatic driving.

Also, the control system of the excavator 100 includes a controller 30, a space recognition device 70, an orientation detection device 71, an input device 72, a positioning device 73, a display device D1, a sound output device D2, a boom angle sensor S1, an arm angle sensor S2, a bucket angle sensor S3, a body inclination sensor S4, and a rotating state sensor S5.

The controller 30 controls the excavator 100, as described above.

For example, the controller 30 sets a target number of rotations per unit time based on a work mode that is configured in advance by a predetermined operation entered through the input device 72 by the operator or the like, and exercises drive control to allow the engine 11 to rotate at a certain speed.

Also, the controller 30 sets a target surface, which is to be referenced while the machine control function is in force, based on the bucket angle sensor S3 and information entered through the input device 72. How the target surface is set will be described later in detail.

Also, for example, the controller 30 outputs, when needed, control commands to a regulator 13, to change the amount of discharge from a main pump 14.

Also, for example, when the operating devices 26 are electrical ones, the controller 30 may control proportional valves 31, as described above, such that the hydraulic actuators run in accordance with the details of operations made on the operating devices 26.

For example, the controller 30 may implement remote operation of the excavator 100 by using the proportional valves 31. To be more specific, the controller 30 may output, to a proportional valve 31, a control command that corresponds to the details of remote operation specified in a remote operation signal received from an external device. Then, using the hydraulic oil supplied from a pilot pump 15, the proportional valve 31 may output a pilot pressure that matches the control command from the controller 30, and apply the pilot pressure to a pilot port of a corresponding control valve in a control valve unit 17. By this means, the details of remote operation are mirrored in the movement of the control valve unit 17, and the hydraulic actuators allow various moving elements (driven elements) to move in accordance with the details of remote operation.

Also, for example, the controller 30 exercises control that relates to a surrounding monitoring function. The surrounding monitoring function allows monitoring entry of a monitoring target object in a predetermined range around the excavator 100 (hereinafter referred to as “monitoring range”), based on information acquired by the space recognition device 70. The process of monitoring entry of the monitoring target object in the monitoring range may be performed by the space recognition device 70, or may take place outside the space recognition device 70 (for example, in the controller 30). The monitoring target object may be, for example, people, trucks, other construction machines, utility poles, hanging loads, pylons, buildings, and so forth.

Also, for example, the controller 30 exercises control related to an object detection notification function. When, for example, the presence of a monitoring target object is identified in the monitoring range by the surrounding monitoring function, the presence of the monitoring target object is reported to the operator in the cabin 10 and to the surroundings of the excavator 100 by the object detection notification function. The controller may implement the object detection notification function by using, for example, the display device D1, a sound output device D2, or the like.

Also, for example, the controller 30 exercises control related to a movement limiting function. When, for example, the presence of a monitoring target object is identified in the monitoring range by the surrounding monitoring function, the movement of the excavator 100 is limited by the movement limiting function. The following description will focus on a case in which the monitoring target object is a person.

For example, the controller 30 may be configured such that if, before the actuators start running, a monitoring target object such as a person is identified to be present in a predetermined range from the excavator 100 (that is, in the monitoring range) based on information acquired by the space recognition device 70, the operator is unable to run the actuators even if the operator operates the operating devices 26, or the actuators are limited to run only at low speed.

To be more specific, when a person is identified to be present in the monitoring range, the controller 30 can lock a gate lock valve, thereby making the actuators unable to operate. In case the operating devices 26 are electrical ones, the actuators can be made inoperable by disabling the signals sent from the controller 30 to the operation proportional valves (proportional valves 31).

Even when other types of operating devices 26 are used, the same applies if operation proportional valves (proportional valves 31) that output pilot pressures that match control commands issued from the controller 30 and apply these pilot pressures to the pilot ports of corresponding control valves in the control valve unit 17 are used.

If it is desirable to make the actuators run slowly, the control signals from the controller 30 to the operation proportional valves (proportional valves 31) may be limited to details that correspond to relatively low pilot pressures, thereby making the actuators run only in slow mode.

In this way, once a monitoring target object that is subject to detection is identified to be present in the monitoring range, even if the operating devices 26 are operated, the actuators are not driven, or are driven only at a movement speed (slow speed) that is slower than the movement speed that matches the operation entered in the operating devices 26. Furthermore, with the excavator 100, if a monitoring target object such as a person is identified to be present in the monitoring range while the operator is operating the operating devices 26, the actuators may be stopped or decelerated regardless of the operator's operation.

To be more specific, if a person is identified to be present in the monitoring range, the actuators may be stopped by locking the gate lock valve. In the event operation proportional valves (proportional valves 31) that output pilot pressures that match control commands from the controller 30 and apply these pilot pressures to the pilot ports of corresponding control valves in the control valve unit are used, the actuators may be made inoperable or may be limited to run only in slow mode by disabling the control signals sent from the controller 30 to the operation proportional valves (proportional valves 31), or by outputting a deceleration command to the operation proportional valves (proportional valves 31).

Also, if the monitoring target object that is detected is a truck, the control for stopping or decelerating the actuators need not be executed. For example, the actuators may be controlled so as to avoid the detected truck. In this way, the type of the detected object may be identified, and the actuators may be controlled based on what is identified.

The space recognition device 70 is configured to recognize an object that is present in the three-dimensional space around the excavator 100, and measure (calculate) the positional relationship between the space recognition device 70 or the excavator 100 and the recognized object, such as the distance therebetween. The space recognition device 70 may be, for example, an ultrasonic sensor, a millimeter wave radar, a monocular camera, a stereo camera, a LIDAR (Light Detecting and Ranging), a distance image sensor, an infrared sensor, and so forth.

With the present embodiment, the space recognition device 70 includes: a front recognition sensor 70F, which is attached to the front end of the upper surface of the cabin 10; a rear recognition sensor 70B, attached to the rear end of the upper surface of the rotating body 3; a left recognition sensor 70L, attached to the left end of the upper surface of the upper rotating body 3; and a right recognition sensor 70R, attached to the right end of the upper surface of the rotating body 3. Also, an upper recognition sensor that recognizes objects in the space above the upper rotating body 3 may be attached to the excavator 100.

The orientation detection device 71 detects information about the relative relationship between the orientation of the upper rotating body 3 and the orientation of the lower traveling body 1 (for example, the rotation angle of the upper rotating body 3 relative to the lower traveling body 1).

The orientation detection device 71 may include, for example, a pair of a ground magnetic sensor attached to the lower traveling body 1 and a ground magnetic sensor attached to the upper rotating body 3. Also, the orientation detection device 71 may include a pair of a GNSS receiver attached to the lower traveling body 1 and a GNSS receiver attached to the upper rotating body 3.

Also, the orientation detection device 71 may include a rotary encoder, a rotary position sensor, or the like that can detect the rotation angle of the upper rotating body 3 relative to the lower traveling body 1, that is, the above-mentioned rotating state sensor S5, and that may be attached to a center joint provided in association with the rotating mechanism 2 that allows relative rotation between the traveling body 1 and the upper rotating body 3.

Also, the orientation detection device 71 may include a camera that is attached to the upper rotating body 3. In this case, the orientation detection device 71 may perform existing image processing on images (input images) captured by the camera attached to the upper rotating body 3, thereby detecting images of the lower traveling body 1 included in the input images.

Then, by using existing image recognition techniques and detecting images of the lower traveling body 1, the orientation detection device 71 may specify the longitudinal direction of the lower traveling body 1, and determine the angle formed between the direction of the front-rear axis of the upper rotating body 3 and the longitudinal direction of the lower traveling body 1. At this time, the direction of the front-rear axis of the upper rotating body 3 can be determined from the position where the camera is mounted. In particular, since the crawler 1C protrudes from the upper rotating body 3, the orientation detection device 71 can identify the longitudinal direction of the lower traveling body 1 by detecting images of the crawler 1C.

Note that, in the event the upper rotating body 3 is structured to be driven in rotary motion by an electric motor instead of the rotary hydraulic motor 2A, a resolver may be used as the orientation detection device 71.

The input device 72 is provided within the reach of the operator seated in the cabin 10, receives various operational inputs from the operator, and outputs signals to match these operational inputs to the controller 30. For example, the input device 72 may include a touch panel that is mounted on a display of a display device that displays images of a variety of information.

Also, for example, the input device 72 may include button switches, levers, toggles, and so forth provided around the display device D1. Also, the input device 72 may include knob switches provided in the operating devices 26 (including, for example, a switch SW provided in the left operating lever 26L). Signals that match the details of operations entered through the input device 72 are taken into the controller 30.

A switch SW is, for example, a push button switch provided at the tip of the left operating lever 26L. The operator can operate the left operating lever 26L while pressing the switch SW. The switch SW may be provided in the right operating lever 26R, or may be provided in another position inside the cabin 10.

The positioning device 73 measures the position and orientation of the upper rotating body 3. The positioning device 73 is, for example, a GNSS (Global Navigation Satellite System) compass, and detects the position and orientation of the upper rotating body 3. Detection signals to indicate the position and orientation of the upper rotating body 3 are taken into the controller 30. Also, among the functions of the positioning device 73, the function to detect the orientation of the upper rotating body 3 may be replaced by a direction sensor attached to the upper rotating body 3.

The display device D1 is provided in a position where the operator seated in the cabin 10 can see the display device D1 with ease, and displays images of a variety of information under the control of the controller 30. The display device D1 may be connected to the controller 30 via an in-vehicle communication network such as a CAN (Controller Area Network), or may be connected to the controller 30 via a one-to-one dedicated line.

The sound output device D2 is, for example, provided in the cabin 10, connected to the controller 30, and outputs sound under the control of the controller 30. The sound output device D2 is, for example, a speaker or a buzzer. The sound output device D2 outputs a variety of information in accordance with sound output commands from the controller 30.

The boom angle sensor S1 is attached to the boom 4, and calculates the elevation angle of the boom 4 (hereinafter referred to as “boom angle θ₁”) relative to the upper rotating body 3, such as, for example, the angle that the straight line connecting between the fulcrum points at both ends of the boom 4 forms with respect to the rotating plane of the upper rotating body 3 in side view.

The boom angle sensor S1 may include, for example, a rotary encoder, an acceleration sensor, a gyro sensor (angular velocity sensor), a 6-axis sensor, an IMU (Inertial Measurement Unit), and so forth, and, hereinafter, the same applies to an arm angle sensor S2, a bucket angle sensor S3, and a body inclination sensor S4. A detection signal from the boom angle sensor S1, indicating the boom angle, is taken into the controller 30.

The arm angle sensor S2 is attached to the arm 5, and calculates the rotation angle of the arm 5 relative to the boom 4 (hereinafter referred to as “arm angle θ₂”), such as, for example, the angle that the straight line connecting between the fulcrum points at both ends of the boom 4 forms with respect to the straight line connecting between the fulcrum points at both ends of the arm 5 in side view. A detection signal from the arm angle sensor S2, indicating the arm angle, is taken into the controller 30.

The bucket angle sensor S3 is attached to the bucket 6, and calculates the rotation angle of the bucket 6 relative to the arm 5 (hereinafter referred to as “bucket angle θ₃”), such as, for example, the angle that the straight line connecting between the fulcrum points at both ends of the arm 5 forms with respect to the straight line connecting between the fulcrum point and the tip (cutting part) of the bucket 6 in side view. A detection signal from the bucket angle sensor S3, indicating the bucket angle, is taken into the controller 30.

The body inclination sensor S4 detects the tilt of the body (for example, the upper rotating body 3) with respect to the horizontal surface. The body inclination sensor S4 is, for example, attached to the upper rotating body 3, and calculates the tilting angles of the excavator 100 (that is, the upper rotating body 3) about the two axes in the front-rear direction and the left-right direction (hereinafter referred to as “front-rear tilting angle” and “left-right tilting angle”). The body inclination sensor S4 may be, for example, an acceleration sensor, a gyro sensor (angular velocity sensor), a 6-axis sensor, an IMU, and so forth. A detection signal from the body inclination sensor S4, indicating the tilting angles (the front-rear tilting angle and the left-right tilting angle), is taken into the controller 30.

The rotating state sensor S5 is attached to the upper rotating body 3, and outputs detection information about the rotating state of the upper rotating body 3. The rotating state sensor S5 detects, for example, the rotating angular velocity and rotating angle of the upper rotating body 3. The rotating state sensor S5 may be, for example, a gyro sensor, a resolver, a rotary encoder, and the like.

In addition, in the event the body inclination sensor S4 includes a gyro sensor, 6-axis sensor, IMU, and the like that can detect the angular velocity about 3 axes, the rotating state (for example, the rotating angular velocity) of the upper rotating body 3 may be detected based on detection signals from the body inclination sensor S4. In this case, the rotating state sensor S5 may be omitted. Next, an example structure of the hydraulic system mounted in the excavator 100 will be described with reference to FIG. 3. FIG. 3 is a diagram that shows an example structure of the hydraulic system mounted in the excavator 100. FIG. 3 shows a mechanical power transmission system, hydraulic oil lines, pilot lines, and an electrical control system with double lines, solid lines, dashed lines, and dotted lines, respectively.

The hydraulic system of the excavator 100 mainly includes an engine 11, regulators 13, main pumps 14, a pilot pump 15, a control valve unit 17, operating devices 26, discharge pressure sensors 28, operation sensors 29, a controller 30, and so forth.

In FIG. 3, the hydraulic system is structured such that hydraulic oil can be circulated from the main pumps 14 driven by the engine 11, to a hydraulic oil tank, via center bypass pipelines 40 or parallel pipelines 42.

The engine 11 is the drive source for the excavator 100. With the present embodiment, the engine 11 is, for example, a diesel engine that runs by maintaining a predetermined number of rotations per unit time. The output shaft of the engine 11 is connected to the input shafts of the main pumps 14 and the pilot pump 15.

The main pumps 14 are structured to supply hydraulic oil to the control valve unit 17 via hydraulic oil lines. With the present embodiment, the main pumps 14 are swash-plate variable displacement hydraulic pumps.

The regulators 13 are structured to control the amount of discharge from the main pumps 14. With the present embodiment, the regulators 13 control the amount of discharge from the main pumps 14, by adjusting the tilting angle of the swashplates of the main pumps 14 in accordance with control commands from the controller 30.

The pilot pump 15 is an example of a pilot pressure generating device, and is structured to supply hydraulic oil to the hydraulic control equipment via pilot lines. With the present embodiment, the pilot pump 15 is a fixed displacement hydraulic pump. However, the pilot pressure generating device may be implemented by the main pumps 14.

That is, the main pumps 14 may have a function to supply hydraulic oil to various types of hydraulic control equipment via pilot lines, in addition to the function to supply hydraulic oil to the control valve unit 17 via hydraulic oil lines. In this case, the pilot pump 15 may be omitted.

The control valve unit 17 is a hydraulic controller that controls the hydraulic system in the excavator 100.

With the present embodiment, the control valve unit 17 includes control valves 171 to 176. The control valves 175 include a control valve 175L and a control valve 175R, and the control valves 176 include a control valve 176L and a control valve 176R. The control valve unit 17 is structured such that the hydraulic oil discharged by the main pumps 14 can be selectively supplied to one or more hydraulic actuators through the control valves 171 to 176.

The control valves 171 to 176 control, for example, the flow rate of hydraulic oil from the main pumps 14 to the hydraulic actuators, and the flow rate of hydraulic oil from the hydraulic actuators to the hydraulic oil tank. The hydraulic actuators include a boom cylinder 7, an arm cylinder 8, a bucket cylinder 9, traveling hydraulic motors 2M, and a rotary hydraulic motor 2A. The traveling hydraulic motors 2M include a left traveling hydraulic motor 2ML and a right traveling hydraulic motor 2MR.

The operating devices 26 are structured to allow the operator to operate the actuators. With the present embodiment, the operating devices 26 include a hydraulic actuator operating device that is structured to allow the operator to operate the hydraulic actuators.

To be more specific, the hydraulic actuator operating device is structured such that the hydraulic oil discharged from the pilot pump 15 can be supplied to the pilot ports of corresponding control valves in the control valve unit 17 via pilot lines. The pressure (pilot pressure) of hydraulic oil supplied to each pilot port varies, depending on the direction of operation and the amount of operation made on the operating devices 26 corresponding to each hydraulic actuator.

The discharge pressure sensors 28 are structured to detect the discharge pressure of the main pumps 14. With the present embodiment, the discharge pressure sensors 28 output the detected values to the controller 30.

The operation sensors 29 are structured to detect the details of operation made on the operating devices 26 by the operator. With the present embodiment, the operation sensors 29 detect the direction of operation and the amount of operation made on the operating devices 26, for each corresponding actuator, and output the detected values to the controller 30.

The main pumps 14 include a left main pump 14L and a right main pump 14R. The left main pump 14L circulates the hydraulic oil to the hydraulic oil tank through a left center bypass pipeline 40L or a left parallel pipeline 42L, and the right main pump 14R circulates the hydraulic oil to the hydraulic oil tank through a right center bypass pipeline 40R or a right parallel pipeline 42R.

The left center bypass pipeline 40L is a hydraulic oil line that passes through the control valves 171, 173, 175L, and 176L positioned in the control valve unit 17. The right center bypass pipeline 40R is a hydraulic oil line that passes through the control valves 172, 174, 175R, and 176R positioned in the control valve unit 17.

The control valve 171 is a spool valve that switches the flow of hydraulic oil such that the hydraulic oil discharged from the left main pump 14L is supplied to the left traveling hydraulic motor 2ML, and the hydraulic oil discharged from the left traveling hydraulic motor 2ML is sent to the hydraulic oil tank.

The control valve 172 is a spool valve that switches the flow of hydraulic oil such that the hydraulic oil discharged from the right main pump 14R is supplied to the right traveling hydraulic motor 2MR, and the hydraulic oil discharged from the right traveling hydraulic motor 2MR is sent to the hydraulic oil tank.

The control valve 173 is a spool valve that switches the flow of hydraulic oil such that the hydraulic oil discharged from the left main pump 14L is supplied to the rotary hydraulic motor 2A and the hydraulic oil discharged from the rotary hydraulic motor 2A is sent to the hydraulic oil tank.

The control valve 174 is a spool valve that switches the flow of hydraulic oil such that the hydraulic oil discharged from the right main pump 14R is supplied to the bucket cylinder 9, and the hydraulic oil in the bucket cylinder 9 is sent to the hydraulic oil tank.

The control valve 175L is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged from the left main pump 14L to the boom cylinder 7. The control valve 175R is a spool valve that switches the flow of hydraulic oil such that the hydraulic oil discharged from the right main pump 14R is supplied to the boom cylinder 7, and the hydraulic oil in the boom cylinder 7 is sent to the hydraulic oil tank.

The control valve 176L is a spool valve that switches the flow of hydraulic oil such that the hydraulic oil discharged from the left main pump 14L is supplied to the arm cylinder 8, and the hydraulic oil in the arm cylinder 8 is sent to the hydraulic oil tank.

The control valve 176R is a spool valve that switches the flow of hydraulic oil such that the hydraulic oil discharged from the right main pump 14R is supplied to the arm cylinder 8, and the hydraulic oil in the arm cylinder 8 is sent to the hydraulic oil tank.

The left parallel pipeline 42L is a hydraulic oil line that runs parallel to the left center bypass pipeline 40L. When the flow of hydraulic oil passing through the left center bypass pipeline 40L is restricted or blocked by any of the control valves 171, 173, and 175L, the left parallel pipeline 42L can supply hydraulic oil to a more downstream control valve.

The right parallel pipeline 42R is a hydraulic oil line that runs parallel to the right center bypass pipeline 40R. When the flow of hydraulic oil passing through the right center bypass pipeline 40R is restricted or blocked by any of the control valves 172, 174, and 175R, the right parallel pipeline 42R can supply hydraulic oil to a more downstream control valve.

The regulators 13 include a left regulator 13L and a right regulator 13R. The left regulator 13L controls the amount of discharge from the left main pump 14L by adjusting the tilting angle of the swashplate of the left main pump 14L according to the discharge pressure of the left main pump 14L. To be more specific, the left regulator 13L reduces the amount of discharge from the left main pump 14L by adjusting the tilting angle of the swashplate of the left main pump 14L in accordance with an increase in the discharge pressure of the left main pump 14L, for example. The same applies to the right regulator 13R. This is to prevent the suction power (absorption horse power) of the main pumps 14, which is given by the product of the discharge pressure and the amount of discharge, from exceeding the output power (output horse power) of the engine 11.

The operating devices 26 include a left operating lever 26L, a right operating lever 26R, and a travel lever 26D. The travel lever 26D includes a left travel lever 26DL and a right travel lever 26DR.

The left operating lever 26L is used for rotating operation and operating the arm 5. When the left operating lever 26L is operated in the front-rear direction, a control pressure to match the amount of the lever operation is introduced to the pilot port of the control valve 176 by using the hydraulic oil discharged from the pilot pump 15. Also, when the left operating lever 26L is operated in the left-right direction, a control pressure to match the amount of the lever operation is introduced to the pilot port of the control valve 173 by using the hydraulic oil discharged from the pilot pump 15.

To be more specific, when the left operating lever 26L is operated in the arm-folding direction, hydraulic oil is introduced to the right pilot port of the control valve 176L and to the left pilot port of the control valve 176R. Also, when the left operating lever 26L is operated in the arm-opening direction, hydraulic oil is introduced to the left pilot port of the control valve 176L and to the right pilot port of the control valve 176R. Also, when the left operating lever 26L is operated in the left-rotating direction, hydraulic oil is introduced to the left pilot port of the control valve 173. When the left operating lever 26L is operated in the right-rotating direction, hydraulic oil is introduced to the right pilot port of control valve 173.

The right operating lever 26R is used to operate the boom 4 and the bucket 6. When the right operating lever R is operated in the front-rear direction, a control pressure to match the amount of the lever operation is introduced to the pilot port of the control valve 175 by using the hydraulic oil discharged from the pilot pump 15. Also, when the right operating lever 26R is operated in the left-right direction, a control pressure to match the amount of the lever operation is introduced to the pilot port of the control valve 174 by using the hydraulic oil discharged from the pilot pump 15.

To be more specific, when the right operating lever 26R is operated in the boom-lowering direction, hydraulic oil is introduced to the left pilot port of the control valve 175R. Also, when the right operating lever 26R is operated in the boom-raising direction, hydraulic oil is introduced to the right pilot port of the control valve 175L and to the left pilot port of the control valve 175R. Also, when the right operating lever 26R is operated in the bucket-folding direction, hydraulic oil is introduced to the right pilot port of the control valve 174. When the right operating lever 26R is operated in the bucket-opening direction, hydraulic oil is introduced to the left pilot port of the control valve 174.

In the following description, the left operating lever 26L that is operated in the left-right direction may be referred to as a “rotation operating lever,” and the left operating lever 26L that is operated in the front-rear direction may be referred to as an “arm operating lever.” Also, the right operating lever 26R that is operated in the left-right direction may be referred to as a “bucket operating lever,” and the right operating lever 26R that is operated in the front-rear direction may be referred to as a “boom-operating lever.”

The travel lever 26D is used to operate a crawler 1C. To be more specific, the left travel lever 26DL is used to operate the left crawler 1CL. The left travel lever 26DL may also be structured to work in conjunction with the left drive pedal.

When the left travel lever 26DL is operated in the front-rear direction, a control pressure to match the amount of the lever operation is introduced to the pilot port of the control valve 171 by using the hydraulic oil discharged from the pilot pump 15. The right travel lever 26DR is used to operate a right crawler 1CR. The right travel lever 26DR may also be structured to work in conjunction with the right drive pedal. When the right travel lever 26DR is operated in the front-rear direction, a control pressure to match the amount of the lever operation is introduced to the pilot port of the control valve 172 by using the hydraulic oil discharged from the pilot pump 15.

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

The operation sensors 29 include operation sensors 29LA, 29LB, 29RA, 29RB, 29DL, and 29DR. The operation sensor 29LA detects the details of operation that the operator performs on the left operating lever 26L in the front-rear direction, and outputs the detected values to the controller 30. The details of operation include, for example, the direction of lever operation, the amount of lever operation (the angle of lever operation), and the like.

Similarly, the operation sensor 29LB detects the details of operation that the operator performs on the left operating lever 26L in the left-right direction, and outputs the detected values to the controller 30. The operation sensor 29RA detects the details of operation that the operator performs on the right operating lever 26R in the front-rear direction, and outputs the detected values to the controller 30.

The operation sensor 29RB detects the details of operation that the operator performs on the right operating lever 26R in the left-right direction, and outputs the detected values to the controller 30. The operation sensor 29DL detects the details of operation that the operator performs on the left operating lever 26DL in the front-rear direction, and outputs the detected values to the controller 30. The operation sensor 29DR detects the details of operation that the operator performs on the right operating lever 26DR in the front-rear direction, and outputs the detected values to the controller 30.

The controller 30 receives the outputs of the operation sensors 29, outputs control commands to the regulators 13 on an as-needed basis, and changes the amount of discharge from the main pumps 14. Also, the controller receives the outputs of control pressure sensors 19 provided upstream of the restrictors 18, outputs control commands to the regulators 13 on an as-needed basis, and changes the amount of discharge from the main pumps 14. The restrictors 18 include a left restrictor 18L and a right restrictor 18R, and the control pressure sensors 19 include a left control pressure sensor 19L and a right control pressure sensor 19R.

In the left center bypass pipeline 40L, the left restrictor 18L is positioned between the most downstream control valve 176L and the hydraulic oil tank.

Consequently, the flow of the hydraulic oil discharged from the left main pump 14L is restricted by the left restrictor 18L. Also, the left restrictor 18L generates a control pressure for controlling the left regulator 13L.

The left control pressure sensor 19L is a sensor for detecting this control pressure, and outputs the detected value to the controller 30. The controller 30 controls the amount of discharge from the left main pump 14L by adjusting the tilting angle of the swashplate of the left main pump 14L in accordance with this control pressure. When the control pressure is higher, the controller 30 lowers the amount of discharge from the left main pump 14L. When the control is pressure is lower, the controller 30 increases the amount of discharge from the left main pump 14L. The amount of discharge from the right main pump 14R is controlled likewise.

To be more specific, as shown in FIG. 3, in standby mode in which none of the hydraulic actuators in the excavator 100 is operated, the hydraulic oil discharged from the left main pump 14L travels through the left center bypass pipeline 40L and reaches the left restrictor 18L. Then, the flow of the hydraulic oil discharged from the left main pump 14L increases the control pressure produced upstream of the left restrictor 18L. As a result of this, the controller 30 lowers the amount of discharge from the left main pump 14L to the minimum possible amount of discharge, and reduces the pressure loss (pumping loss) that is produced when the discharged hydraulic oil passes through the left center bypass pipeline 40L.

On the other hand, when one of the hydraulic actuators is operated, the hydraulic oil discharged from the left main pump 14L flows into the hydraulic actuator that is operated, via a control valve corresponding to the hydraulic actuator that is operated. Then, the flow of the hydraulic oil discharged from the left main pump 14L makes the amount of hydraulic oil to reach the left restrictor 18L decrease or vanish, thus lowering the control pressure that is produced upstream of the left restrictor 18L.

As a result of this, the controller 30 increases the amount of discharge from the left main pump 14L, circulates a sufficient amount of hydraulic oil in the hydraulic actuator that is operated, and ensures that the hydraulic actuator that is operated is driven. Note that the controller 30 likewise controls the amount of discharge from the right main pump 14R.

With the above-described structure, the hydraulic system shown in FIG. 3 can reduce the wasteful energy consumption in the main pumps 14 while in standby mode. The wasteful energy consumption includes the pumping loss that the hydraulic oil discharged from the main pumps 14 produces in the center bypass pipeline 40. Also, when starting a hydraulic actuator, the hydraulic system shown in FIG. 3 can reliably supply a necessary and sufficient amount of hydraulic oil from the main pumps 14 to the hydraulic actuator to be started.

Next, a structure for allowing the controller 30 to run the actuators by using a machine control function will be described with reference to FIG. 4A to FIG. 4D. FIG. 4A to FIG. 4D are diagrams that each extract a part of the hydraulic system. To be more specific, FIG. 4A is a diagram that extracts a part of the hydraulic system that relates to the operation of the arm cylinder 8, and FIG. 4B is a diagram that extracts a part of the hydraulic system that relates to the operation of the boom cylinder 7. FIG. 4C is a diagram that extracts a part of the hydraulic system that relates to the operation of the bucket cylinder 9, and FIG. 4D is a diagram that extracts a part of the hydraulic system that relates to the operation of the rotary hydraulic motor 2A.

As shown in FIG. 4A to FIG. 4D, the hydraulic system includes proportional valves 31. The proportional valves 31 include proportional valves 31AL to 31DL and 31AR to 31DR.

The proportional valves 31 function as control valves for machine control. The proportional valves 31 are positioned in pipelines connecting the pilot pumps 15 and the pilot ports of corresponding control valves in the control valve unit 17, and structured such that the flow area of the pipelines can be changed. With the present embodiment, the proportional valves 31 work in accordance with control commands from the controller 30.

Consequently, regardless of operations that the operator performs on the operating devices 26, the controller 30 can supply the hydraulic oil discharged from the pilot pumps 15, to the pilot ports of the corresponding control valves in the control valve unit 17, via the proportional valves 31. Then, the controller 30 can make the pilot pressures produced by the proportional valves 31 act on the pilot ports of the corresponding control valves.

By means of this structure, even when a specific operating device 26 is not being operated, the controller can still run the hydraulic actuator associated with that specific operating device 26. Also, even when a specific operating device 26 is being operated, the controller 30 can force the movement of the hydraulic actuator associated with that specific operating device 26 to a stop.

For example, as shown in FIG. 4A, the left operating lever 26L is used to operate the arm 5. To be more specific, the left operating lever 26L applies a pilot pressure that matches the operation of the left operating lever 26L in the front-rear direction, to pilot ports of the control valves 176, by using the hydraulic oil discharged from the pilot pumps 15. To be more specific, when the left operating lever 26L is operated in the direction to fold the arm (rear direction), a pilot pressure that matches the amount of the operation is applied to the right pilot port of the control valve 176L and to the left pilot port of the control valve 176R. Also, when the left operating lever 26L is operated in the direction to open the arm (forward direction), a pilot pressure that matches the amount of the operation is applied to the left pilot port of the control valve 176L and to the right pilot port of the control valve 176R.

The operating devices 26 are provided with switches SW. With the present embodiment, the switches SW include a switch SW1 and a switch SW2.

The switch SW1 is a push button switch provided at the tip of the left operating lever 26L. The operator can operate the left operating lever 26L while pressing the switch SW1. The switch SW1 may be provided in the right operating lever 26R, or may be provided in another position inside the cabin 10.

The switch SW2 is a push button switch provided at the tip of the left travel lever 26DL. The operator can operate the left travel lever 26DL while pressing the switch SW2. The switch SW2 may be provided in the right travel lever 26DR, or may be provided in another position inside the cabin 10.

The operation sensor 29LA detects the details of operation that the operator performs on the left operating lever 26L in the front-rear direction, and outputs the detected values to the controller 30.

The proportional valve 31AL works in accordance with control commands (electric current commands) output by the controller 30. Then, the proportional valve 31AL adjusts the pilot pressures produced by the hydraulic oil introduced from the pilot pumps 15 to the right pilot port of the control valve 176L and to the left pilot port of the control valve 176R via the proportional valve 31AL.

The proportional valve 31AR works in accordance with control commands (electric current commands) output by the controller 30. Then, the proportional valve 31AR adjusts the pilot pressures produced by the hydraulic oil introduced from the pilot pumps 15 to the left pilot port of the control valve 176L and to the right pilot port of the control valve 176R via the proportional valve 31AR. The proportional valve 31AL can adjust the pilot pressures such that the control valve 176L and the control valve 176R can be stopped at any valve positions. Similarly, the proportional valve 31AR can adjust the pilot pressures such that the control valve 176L and the control valve 176R can be stopped at any valve positions.

By means of this structure, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15, to the right pilot port of the control valve 176L and to the left pilot port of the control valve 176R, via the proportional valve 31AL, in accordance with arm-folding operations by the operator. The controller 30 can also supply the hydraulic oil discharged from the pilot pump 15, to the right pilot port of the control valve 176L and to the left pilot port of the control valve 176R, via the proportional valve 31AL, independently of arm-folding operations by the operator. That is, the controller 30 can fold the arm 5 in accordance with arm-folding operations by the operator or independently of arm-folding operations by the operator.

Also, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15, to the left pilot port of the control valve 176L and to the right pilot port of the control valve 176R, via the proportional valve 31AR, in accordance with arm-opening operations by the operator.

The controller 30 can also supply the hydraulic oil discharged from the pilot pump 15, to the left pilot port of the control valve 176L and to the right pilot port of the control valve 176R, via the proportional valve 31AR, independently of arm-opening operations by the operator. That is, the controller 30 can open the arm 5 in accordance with arm-opening operations by the operator or independently of arm-opening operations by the operator.

Also, with this structure, even when the operator is performing an arm-folding operation, the controller 30 can reduce the pilot pressures that act on the closing-side pilot ports of the control valves 176 (the left pilot port of the control valve 176L and the right pilot port of the control valve 176R) on an as-needed basis, and force the folding movement of the arm 5 to a stop. The same applies to the case in which the opening movement of the arm 5 is forced to a stop while the operator is performing an arm-opening operation.

Alternatively, even when the operator is performing an arm-folding operation, the controller 30 may, if necessary, control the proportional valve 31AR, increase the pilot pressures that act on the opening-side pilot ports of the control valves 176 (the right pilot port of the control valve 176L and the left pilot port of the control valve 176R), which are provided on the opposite side of the closing-side pilot ports of the control valves 176, and force the control valves 176 back to neutral positions, such that the folding movement of the arm 5 is forced to a stop. The same applies to the case in which the opening movement of the arm 5 is forced to a stop while the operator is performing an arm-opening operation.

Although not described below with reference to FIG. 4B to FIG. 4D, the same applies when the movement of the boom 4 is forced to a stop while the operator is performing a boom-raising operation or a boom-lowering operation, when the movement of the bucket 6 is forced to a stop while the operator is performing a bucket-folding operation or a bucket-opening operation, and when the rotating movement of the upper rotating body 3 is forced to a stop while the operator is performing a rotating operation. Furthermore, the same applies when the traveling movement of the lower traveling body 1 is forced to a stop while the operator is performing a traveling operation.

Also, as shown in FIG. 4B, the right operating lever 26R is used to operate the boom 4. To be more specific, using the hydraulic oil discharged from the pilot pump 15, the right operating lever 26R applies pilot pressures to the pilot ports of the control valves 175 in accordance with the operation of the right operating lever 26R in the front-rear direction. To be more specific, when the right operating lever 26R is operated in a direction to raise the boom 4 (rear direction), a pilot pressure that matches the amount of the operation is applied to the right pilot port of the control valve 175L and to the left pilot port of the control valve 175R. Likewise, when the right operating lever 26R is operated in a direction to lower the boom 4 (forward direction), a pilot pressure that matches the amount of the operation is applied to the right pilot port of the control valve 175R.

The operation sensor 29RA detects the details of operations that the operator performs on the right operating lever 26R in the front-rear direction, and outputs the detected values to the controller 30.

The proportional valve 31BL works in accordance with control commands (electric current commands) output from the controller 30. Then, the proportional valve 31BL adjusts the pilot pressures produced by the hydraulic oil that is introduced from the pilot pump 15 to the right pilot port of the control valve 175L and to the left pilot port of the control valve 175R via the proportional valve 31BL. The proportional valve 31BR works in accordance with control commands (electric current commands) from the controller 30.

Then, the proportional valve 31BR adjusts the pilot pressure produced by the hydraulic oil that is introduced from the pilot pump 15 to the right pilot port of the control valve 175R via the proportional valve 31BR. The proportional valve 31BL can adjust the pilot pressure such that the control valve 175L and the control valve 175R can be stopped at any valve positions. Also, the proportional valve 31BR can adjust the pilot pressure such that the control valve 175R can be stopped at any valve position.

Given this structure, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15, to the right pilot port of the control valve 175L and to the left pilot port of the control valve 175R, via the proportional valve 31BL, in accordance with boom-raising operations by the operator. The controller 30 can also supply the hydraulic oil discharged from the pilot pump 15, to the right pilot port of the control valve 175L and to the left pilot port of the control valve 175R, via the proportional valve 31BL, independently of boom-raising operations by the operator. That is, the controller 30 can raise the boom 4 in accordance with boom-raising operations by the operator or independently of boom-raising operations by the operator.

Also, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15, to the right pilot port of the control valve 175R, via the proportional valve 31BR, in accordance with boom-lowering operations by the operator. The controller 30 can also supply the hydraulic oil discharged from the pilot pump 15, to the right pilot port of the control valve 175R, via the proportional valve 31BR, independently of boom-lowering operations by the operator. That is, the controller 30 can lower the boom 4 in accordance with boom-lowering operations by the operator or independently of boom-lowering operations by the operator.

Furthermore, as shown in FIG. 4C, the right operating lever 26R is also used to operate the bucket 6. To be more specific, using the hydraulic oil discharged from the pilot pump 15, the right operating lever 26R applies pilot pressures to pilot ports of a control valve 174 in accordance with operations that the operator performs in the left-right direction.

To be more specific, when the right operating lever 26R is operated in a direction to fold the bucket (left direction), a pilot pressure that matches the amount of the operation is applied to the left pilot port of the control valve 174. Also, when the right operating lever 26R is operated in a direction to open the bucket (right direction), a pilot pressure that matches the amount of the operation is applied to the right pilot port of the control valve 174.

The operation sensor 29RB detects the details of operation that the operator performs on the right operating lever 26R in the left-right direction, and outputs the detected values to the controller 30.

The proportional valve 31CL works in accordance with control commands (electric current commands) from the controller 30. Then, the proportional valve 31CL adjusts the pilot pressure produced by the hydraulic oil that is introduced from the pilot pump 15 to the left pilot port of the control valve 174 via the proportional valve 31CL. The proportional valve 31CR works in accordance with control commands (electric current commands) from the controller 30.

Then, the proportional valve 31BR adjusts the pilot pressure produced by the hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 174 via the proportional valve 31CR. The proportional valve 31CL can adjust the pilot pressure such that the control valve 174 can be stopped at any valve position. Similarly, the proportional valve 31CR can adjust the pilot pressure such that the control valve 174 can be stopped at any valve position.

Given this structure, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15, to the left pilot port of the control valve 174, via the proportional valve 31CL, in accordance with bucket-folding operations by the operator. The controller 30 can also supply the hydraulic oil discharged from the pilot pump 15, to the left pilot port of the control valve 174, via the proportional valve 31CL, independently of bucket-folding operations by the operator. That is, the controller 30 can fold the bucket 6 in accordance with bucket-folding operations by the operator or independently of bucket-folding operations by the operator.

Also, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15, to the right pilot port of the control valve 174, via the proportional valve 31CR, in accordance with bucket-opening operations by the operator. Also, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15, to the right pilot port of the control valve 174, via the proportional valve 31CR, independently of bucket-opening operations by the operator. That is, the controller 30 can open the bucket 6 in accordance with bucket-opening operations by the operator or independently of bucket-opening operations by the operator.

Also, as shown in FIG. 4D, the left operating lever 26L is also used to operate the rotating mechanism 2. To be more specific, using the hydraulic oil discharged from the pilot pump 15, the left operating lever 26L applies pilot pressures to pilot ports of a control valve 173 in accordance with operations made in the left-right direction.

To be more specific, when the left operating lever 26L is operated in the left-rotation direction (left direction), a pilot pressure that matches the amount of the operation is applied to the left pilot port of the control valve 173. Also, when the left operating lever 26L is operated in the right-rotation direction (right direction), a pilot pressure that matches the amount of the operation is applied to the left pilot port of the control valve 173.

The operation sensor 29LB detects the details of operation that the operator performs on the left operating lever 26L in the left-right direction, and outputs the detected values to the controller 30.

The proportional valve 31DL works in accordance with control commands (electric current commands) from the controller 30. Then, the proportional valve 31DL adjusts the pilot pressure produced by the hydraulic oil that is introduced from the pilot pump 15 to the left pilot port of the control valve 173 via the proportional valve 31DL. The proportional valve 31DR works in accordance with control commands (electric current commands) from the controller 30.

Then, the proportional valve 31DR adjusts the pilot pressure produced by the hydraulic oil that is introduced from the pilot pump 15 to the right pilot port of the control valve 173 via the proportional valve 31DR. The proportional valve 31DL can adjust the pilot pressure such that the control valve 173 can be stopped at any valve position. Similarly, the proportional valve 31DR can adjust the pilot pressure such that the control valve 173 can be stopped at any valve position.

Given this structure, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15, to the left pilot port of the control valve 173, via the proportional valve 31DL, in accordance with left-rotating operations by the operator. Also, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15, to the left pilot port of the control valve 173, via the proportional valve 31DL, independently of left-rotating operations by the operator. That is, the controller 30 can rotate the rotating mechanism 2 to the left in accordance with left-rotating operations by the operator or independently of left-rotating operations by the operator.

Also, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15, to the right pilot port of the control valve 173, via the proportional valve 31DR, in accordance with right-rotating operations by the operator. Also, the controller 30 can supply the hydraulic oil discharged from the pilot pump 15, to the right pilot port of the control valve 173, via the proportional valve 31DR, independently of right-rotating operations by the operator. That is, the controller 30 can rotate the rotating mechanism 2 to the right in accordance with right-rotating operations by the operator or independently of right-rotating operations by the operator.

Next, the machine guidance function and machine control function of the excavator 100 will be described with reference to FIG. 5. FIG. 5 is a block diagram that shows an example structure related to the machine guidance function and machine control function of the excavator.

The controller 30 exercises control over the excavator 100 with respect to the machine guidance function that, for example, guides the operator's manual operation of the excavator 100.

The controller 30 reports work information such as the distance between the target surface and the tip of the attachment AT, or, to be more specific, the working part of the end attachment AT, to the operator, through the display device D1, sound output device D2, and so forth.

To be more specific, the controller 30 acquires information from the boom angle sensor S1, arm angle sensor S2, bucket angle sensor S3, body inclination sensor S4, rotating state sensor S5, space recognition device 70, positioning device V1, input device 72, and so forth.

Also, the controller 30 sets the target surface by, for example, generating data related to the target surface in response to the operation for setting the target surface by the operator, and storing the data in a storage device or the like in the controller 30 on a temporary basis. Then, the controller 30 may calculate the distance between the working part of the bucket 6 and the target surface, and report the calculated distance to the operator by displaying an image on the display device D1 or by outputting a sound from the sound output device D2.

The controller 30 of the present embodiment uses the back surface of the bucket 6 as a reference surface, and uses a plane having a set angle with respect to the reference surface as a target surface. Details of setting the target surface will be described later.

Note that, with the excavator 100 of the present embodiment, if a design surface (an example of a target working surface) is set apart from the target surface, work information such as the distance from the design surface to the working part of the bucket 6 may be reported to the operator through the display device D1, sound output device D2, or the like.

Data about the design surface is stored in an external storage device or the like, which is connected to an internal memory or the controller 30, for example, in accordance with configuration inputs from the operator through the input device 72, or by being downloaded from an external source (for example, a predetermined management server).

Data about the design surface is expressed, for example, in a reference coordinate system. The reference coordinate system is, for example, the world geodetic system. The world geodetic system is a three-dimensional orthogonal XYZ coordinate system, in which the center of gravity of the Earth is the origin, with the X-axis pointing toward the intersection of the Greenwich meridian and the equator, the Y-axis pointing toward 90 degrees east longitude, and the Z-axis pointing toward the north pole. For example, the operator may set an arbitrary point on the work site as a point of reference, and, using the input device 72, sets a design surface based on the relative positional relationship with respect to the reference point.

The working part of the bucket 6 is, for example, the teeth of the bucket 6, the back surface of the bucket 6, and so forth. Also, if a breaker is used as the end attachment instead of the bucket 6, the breaker's tip serves as the working part. By this means, the controller can report work information to the operator through the display device D1, sound output device D2, and the like, and guide the operator in operating the excavator 100 through the operating devices 26.

Also, the controller 30 exercises control over the excavator 100 with respect to the machine control function that, for example, assists the operator's manual operation of the excavator 100, moves the excavator 100 automatically or autonomously, and so forth. To be more specific, the controller 30 is structured to obtain a target trajectory, which is the trajectory to be followed by the position of point of reference that is configured for control (hereinafter simply referred to as “control reference point”), for example, in the working part of the attachment.

If there is a working target (for example, the ground, earth and sand in the bed of a dump truck, which will be described later, etc.) that the end attachment can come into contact with, for example, during excavation, compaction, and so forth, the working part of the end attachment (for example, the teeth or the back surface of the bucket 6) may be set as the control reference point.

Also, when there is no working target that the end attachment can come into contact with, for example, during boom-raising rotating movement, unloading of earth and sand, boom-lowering rotating movement, and so forth, which will be described later, any part (for example, the lower end or teeth of the bucket 6) that can define the position of the end attachment in these movements can be set as the control reference point.

For example, the controller 30 derives the target trajectory based on data that indicates what target surface is set. The controller 30 may derive the target trajectory based on information about the terrain around the excavator 100 as recognized by the space recognition device 70. Also, the controller 30 may derive information about the past tracks of the working part such as the teeth of the bucket 6, from among the past outputs of the attitude detection device temporarily stored in an internal transitory storage device, and derive the target trajectory based on that information. Also, the controller 30 may derive the target trajectory based on the current position of a predetermined part of the attachment and data about the target surface.

Note that the attitude detection device includes, for example, a boom angle sensor S1, an arm angle sensor S2, a bucket angle sensor S3, and so forth.

For example, when the operator performs a ground excavation operation or leveling operation manually, the controller 30 controls at least one of the boom 4, the arm 5, and the bucket 6 to move automatically, such that the target surface and the position of the tip of the bucket 6 (to be more specific, the working part of the bucket 6 such as its teeth or back) meet. To be more specific, when the operator operates the left operating lever 26L in the front-rear direction while operating (pressing) the switch SW, the controller 30 controls at least one of the boom 4, the arm 5, and the bucket 6, in accordance with that operation, such that the target surface and the position of the tip of the bucket 6 meet. To be more specific, the controller 30 controls the proportional valves 31 as described above, and controls at least one of the boom 4, the arm 5, and the bucket 6 to move automatically. By this means, the operator can allow the excavator 100 to perform excavation or leveling along the target surface, by only operating the left operating lever 26L.

Next, examples of the machine control function of the excavator 100 according to the present embodiment will be described in detail with reference to FIG. 6A and FIG. 6B.

Detailed structures related to examples of the machine control function of the excavator 100 will be described with reference to FIG. 6A and FIG. 6B.

FIG. 6A and FIG. 6B are functional block diagrams that each show an example of a detailed structure related to the machine control function of the excavator 100 according to the present embodiment. To be more specific, FIG. 6A is a first functional block diagram that shows a detailed structure related to the semi-automatic driving function of the excavator 100, and FIG. 6B is a second functional block diagram that shows a detailed structure related to the semi-automatic driving function of the excavator 100.

As shown in FIG. 6A and FIG. 6B, the controller 30, which implements the semi-automatic driving function of the excavator 100, includes an operation detail acquiring part 3001, a target surface acquiring part 3002, a target trajectory configuration part 3003, a current position calculation part 3004, a target position calculation part 3005, a bucket shape acquiring part 3006, a primary element configuration part 3007, a control reference point configuration part 3008, a movement command generation part 3009, a pilot command generation part 3010, and an attitude angle calculation part 3011, as functional parts related to the machine control function. For example, when the switch SW is pressed and operated, these functional parts repeat the movements described below, in a predetermined control cycle.

The operation detail acquiring part 3001 acquires the details of operation regarding the front-rear tilting operations of the left operating lever 26L, based on detection signals taken in from the operation sensor 29LA.

For example, the operation detail acquiring part 3001 acquires (calculates) the direction of operation (that is, whether the left operating lever 26L is operated in the forward direction or the rear direction) and the amount of operation, as details of operation. Also, when the excavator 100 is remotely operated, the semi-automatic driving function of the excavator 100 may be implemented based on the details of remote operation signals received from an external device. In this case, the operation detail acquiring part 3001 acquires information that indicates the details of remote operation based on remote operation signals received from the external device.

The operation detail information includes, for example, details of a predetermined work performed by the excavator 100, details of operations that constitute the predetermined work, operating conditions related to the predetermined work, trigger conditions for starting the work, and so forth. The predetermined work may include, for example, excavation, loading, land leveling, and so forth. In the event the predetermined work is excavation, operations that constitute the predetermined work include, for example, an excavation operation, a boom-raising rotating operation, an earth removing operation, a boom-lowering rotating operation, and so forth. Furthermore, in the event the predetermined work is excavation, the operating conditions include conditions regarding the depth of excavation, the length of excavation, and so forth.

The target surface acquiring part 3002 generates and acquires data about the target surface according to the operator's operation, for example. To be more specific, for example, the target surface acquiring part 3002 acquires an angle entered by the operator through the input device 72, and sets a surface having the entered angle with respect to the back surface (reference surface) of the bucket 6 as the target surface. Then, the target surface acquiring part 3002 acquires data about the target surface. Note that the reference surface is not limited to the back surface of the bucket 6, and any surface may be used.

Note that, with the present embodiment, if a design surface (target working surface) is set in advance apart from the target surface, the target surface acquiring part 3002 may acquire data about the design surface from an internal memory, a predetermined external storage device, and so forth.

The target trajectory configuration part 3003 configures information about the target trajectory of the tip of the attachment AT, in order to move the tip of the attachment AT along the target surface, based on the data about the target surface. To be more specific, the tip of the attachment AT refers to a predetermined part of the end attachment (for example, the teeth or back surface of the bucket 6) that serves as a point of reference for control.

For example, as the information about the target trajectory, the target trajectory configuration part 3003 may configure the tilting angle of the target surface in the front-rear direction, with reference to the body (upper rotating body 3) of the excavator 100. Also, a range of errors that can be allowed (hereinafter referred to as “allowable error range”) may be configured for the target trajectory. In this case, the information about the target trajectory may include information about the allowable error range.

The current position calculation part 3004 calculates the position (current position) of the control reference point in the attachment AT (for example, the working part of the bucket 6 such as its teeth or back). To be more specific, the current position calculation part 3004 calculates the (current) position of the control reference point in the attachment AT based on a boom angle θ1, an arm angle θ2, and a bucket angle θ3, calculated by an attitude angle calculation part 3011, which will be described later.

In the semi-automatic driving function of the excavator 100, the target position calculation part 3005 calculates the target position of the tip (control reference point) of the attachment AT based on the details of operational inputs by the operator (for example, operation of the left operating lever 26L in the front-rear direction), information about the configured target trajectory, and the current position of the control reference point (working part) in the attachment AT.

The details of operation include, for example, the direction of operation and the amount of operation.

Assuming that the arm 5 moves according to the direction of operation and the amount of operation indicated in the operator's operational inputs, this target position is the position on the target trajectory that should be reached in the current control cycle.

The target position calculation part 3005 may calculate the target position of the tip of the attachment AT by using, for example, a map, an algorithm, and so forth, stored in advance in a non-volatile internal memory or the like.

Also, in the autonomous driving function of the excavator 100, the target position calculation part 3005 calculates the target position of the tip (control reference point) of the attachment AT based on an operational command entered from the operation detail acquiring part 3001, information about the configured target trajectory, and the current position of the control reference point (working part) in the attachment AT. By this means, the controller 30 can autonomously control the excavator 100, independently of operations by the operator.

The bucket shape acquiring part 3006 acquires data about pre-registered shapes of the bucket 6 from, for example, an internal memory, a predetermined external storage device, or the like. At this time, provided that a plurality of types of data are registered in advance about the shape of the bucket 6, the bucket shape acquiring part 3006 may acquire data about a shape of the bucket 6 that is specified by a configuration operation given via the input device 72.

Among the moving elements constituting the attachment AT (that is, the actuators that drive these moving elements), the primary element configuration part 3007 configures a moving element (actuator) (hereinafter referred to as “primary element”) that works in accordance with operational inputs from the operator or operational commands.

Hereinafter, a moving element that moves in accordance with the operator's operational inputs or operational commands that relate to the autonomous driving function, and the actuator that drives that moving element, may be collectively referred to as “primary elements,” or each one of them may be individually referred to as a “primary element.” The same applies to secondary elements as well, which will be described later.

The control reference point configuration part 3008 configures a point of reference for control in the attachment AT. For example, the control reference point configuration part 3008 may configure a control reference point in the attachment AT in accordance with an operation by the operator through the input device 72, or the like.

Also, for example, the control reference point configuration part 3008 may automatically change the configuration of the control reference point in the attachment AT when a predetermined condition is satisfied.

The movement command generation part 3009 generates a command value β_1r for moving the boom 4 (hereinafter referred to as “boom command value”), a command value β_2r for moving the arm 5 (hereinafter referred to as “arm command value”), and a command value β_3r for moving the bucket 6 (hereinafter referred to as “bucket command value”), based on the target position of the control reference point in the attachment AT. For example, boom command value β_1r, arm command value β_2r, and bucket command value β_3r are, respectively, the angular velocity of the boom 4 (hereinafter referred to as “boom angular velocity”), the angular velocity of the arm 5 (hereinafter referred to as “boom angular velocity”), and the angular velocity of the bucket 6 (hereinafter referred to as “bucket angular velocity”), that are necessary for the control reference point in the attachment AT to arrive at the target position. The movement command generation part 3009 includes a primary command value generation part 3009A and a secondary command value generation part 3009B.

Note that the boom command value, arm command value, and bucket command value may be the boom angle, arm angle, and bucket angle when the control reference point in the attachment AT arrives at the target position. Also, the boom command value, arm command value, and bucket command value may be the angular acceleration or the like that is necessary for the control reference point in the attachment AT to arrive at the target position.

The primary command value generation part 3009A generates a command value β_m (hereinafter referred to as “primary command value”) for the movement of the primary element among the moving elements constituting the attachment AT (the boom 4, the arm 5, and the bucket 6). For example, when the boom 4 (boom cylinder 7) is set as the primary element by the primary element configuration part 3007, the primary command value generation part 3009A generates boom command value β_1r as primary command value β_m, and outputs this to the pilot command generation part 3010A, which will be described later.

Also, when the arm 5 (arm cylinder 8) is set as the primary element by the primary element configuration part 3007, the primary command value generation part 3009A generates arm command value β_2r, and outputs this to the arm pilot command generation part 3010B. Also, when the bucket 6 (bucket cylinder 9) is set as the primary element by the primary element configuration part 3007, the primary command value generation part 3009A generates bucket command value β_3r as primary command value β_m, and outputs this to the bucket pilot command generation part 3010C.

To be more specific, the primary command value generation part 3009A generates primary command value β_m that matches the details of operation (the direction of operation and the amount of operation) by the operator or an operational command. For example, the primary command value generation part 3009A may generate boom command value β_1r, arm command value β_2r, and bucket command value β_3r as primary command values, based on a predetermined map, a conversion formula, and the like that defines the relationship between the details of operation by the operator or an operational command, and each of boom command value β_1r, arm command value β_2r, and bucket command value β_3r.

The secondary command value generation part 3009B generates command values (hereinafter referred to as “secondary command values”) β_s1 and β_s2 related to the movement of secondary elements, among the moving elements that constitute the attachment AT, such that the control reference point in the attachment AT moves along the target surface in conjunction with (in sync with) the operation of the primary element.

For example, when the boom 4 is set as the primary element by the primary element configuration part 3007, the secondary command value generation part 3009B generates arm command value β_2r and bucket command value β_3r as secondary command values β_s1 and β_s2, and output these to the arm pilot command generation part 3010B and to the bucket pilot command generation part 3010C, respectively.

When the arm 5 is set as the primary element by the primary element configuration part 3007, the secondary command value generation part 3009B generates boom command value β_1r and bucket command value β_3r as secondary command values β_s1 and β_s2, and outputs these to the boom pilot command generation part 3010A and to the bucket pilot command generation part 3010C, respectively.

When the bucket 6 is set as the primary element by the primary element configuration part 3007, the secondary command value generation part 3009B generates boom command value β_1r and arm command value β_2r as secondary command values β_s1 and β_s2, and outputs these to the boom pilot command generation part 3010A and to the arm pilot command generation part 3010B, respectively.

To be more specific, the secondary command value generation part 3009B generates secondary command values β_s1 and β_s2 such that the secondary elements move in accordance with (in sync with) the movement of the primary element corresponding to primary command value β_m and the control reference point in the attachment AT arrives at the target position (that is, moves along the target surface).

In this way, the controller 30 operates two secondary elements in the attachment AT in accordance with (in sync with) the operation of the primary element of the attachment AT that follows operational inputs or operation commands from the operator. Therefore, the controller 30 can move the control reference point in the attachment AT along the target surface.

In other words, the primary element (its hydraulic actuator) moves in accordance with operational inputs from the operator or operational commands, and the movement of the secondary elements (their hydraulic actuators) is controlled in accordance with the movement of the primary element (its hydraulic actuator) such that the tip (control reference point) in the attachment AT, such as the teeth of the bucket 6, moves along the target surface.

The pilot command generation part 3010 generates command values for the pilot pressures (hereinafter referred to as “pilot pressure command values”) to apply to the control valves 174 to 176, so as to achieve the boom angular velocity, arm angular velocity, and bucket angular velocity that match boom command value β_1r, arm command value β_2r, and bucket command value β_3r. The pilot command generation part 3010 includes a boom pilot command generation part 3010A, an arm pilot command generation part 3010B, and a bucket pilot command generation part 3010C.

The boom pilot command generation part 3010A generates the pilot pressure command values to apply to the control valves 175L and 175R, which are associated with the boom cylinder 7 that drives the boom 4, based on the deviation between boom command value β_1r and the value (measured value) of the current boom angular velocity calculated by a boom angle calculation part 3011A, which will be described later. Then, the boom pilot command part generation 3010A outputs control currents that match the generated pilot pressure command values, to the proportional valves 31BL and 31BR.

By this means, as described above, pilot pressures that match the pilot pressure command values output from the proportional valves 31BL and 31BR are applied to the corresponding pilot ports of the control valves 175L and 175R. Then, by the working of the control valves 175L and 175R, the boom cylinder 7 moves, and the boom 4 moves so as to achieve a boom angular velocity that matches boom command value β_1r.

The arm pilot command generation part 3010B generates the pilot pressure command values to apply to the control valves 176L and 176R, which are associated with the arm cylinder 8 that drives the arm 5, based on the deviation between arm command value β_2r and the value (measured value) of the current arm angular velocity calculated by an arm angle calculation part 3011B, which will be described later. Then, the arm pilot command part generation 3010B outputs control currents that match the generated pilot pressure command values, to the proportional valves 31AL and 31AR.

By this means, as described above, pilot pressures that match the pilot pressure command values output from the proportional valves 31AL and 31AR are applied to the corresponding pilot ports of the control valves 176L and 176R. Then, by the working of the control valves 176L and 176R, the arm cylinder 8 moves, and the arm 5 moves so as to achieve an arm angular velocity that matches arm command value β_2r.

The bucket pilot command generation part 3010C generates the pilot pressure command values to apply to the control valve 174, corresponding to the bucket cylinder 9 that drives the bucket 6, based on the deviation between bucket command value β_3r and the value (measured value) of the current bucket angular velocity calculated by the bucket angle calculation part 3011C, which will be described later. Then, the bucket pilot command part generation 3010C outputs control currents that match the generated pilot pressure command values, to the proportional valves 31CL and 31CR.

By this means, as described above, pilot pressures that match the pilot pressure command values output from the proportional valves 31CL and 31CR are applied to the corresponding pilot ports of the control valve 174. Then, by the working of the control valve 174, the bucket cylinder 9 moves, and the bucket 6 moves so as to achieve a bucket angular velocity that matches bucket command value β_3r.

The attitude angle calculation part 3011 calculates (measures) the (current) boom angle, arm angle, and bucket angle, as well as boom angular velocity, arm angular velocity, and bucket angular velocity, based on detection signals from the boom angle sensor S1, arm angle sensor S2, and bucket angle sensor S3. The attitude angle calculation part 3011 includes a boom angle calculation part 3011A, an arm angle calculation part 3011B, and a bucket angle calculation part 3011C.

The boom angle calculation part 3011A calculates (measures) the boom angle, boom angular velocity, and so forth, based on detection signals taken in from the boom angle sensor S1. By this means, the boom pilot command generation part 3010A can exercise feedback control for the movement of the boom cylinder 7, based on measurement results by the boom angle calculation part 3011A.

The arm angle calculation part 3011B calculates (measures) the arm angle, arm angular velocity, and so forth, based on detection signals taken in from the arm angle sensor S2. By this means, the arm pilot command generation part 3010B can exercise feedback control for the movement of the arm cylinder 8, based on measurement results by the arm angle calculation part 3011B.

The bucket angle calculation part 3011C calculates (measures) the bucket angle, bucket angular velocity, and so forth, based on detection signals taken in from the bucket angle sensor S3. By this means, the bucket pilot command generation part 3010C can exercise feedback control for the movement of the bucket cylinder 9, based on measurement results by the bucket angle calculation part 3011C.

Next, configuration of the target surface according to the present embodiment will be described with reference to FIG. 7 and FIG. 8. FIG. 7 is a diagram that explains the target surface.

With the present embodiment, the back surface 6c of the bucket 6 is used as a reference surface, and a plane that forms a certain angle with respect to this reference surface G1 is used as a target surface G2. The certain angle may be, for example, a set angle that is entered from the input device 72 by the operator's operation.

The example of FIG. 7 shows a state in which the operator enters an angle θa as a set angle, and a plane that forms the angle θa with respect to the back surface 6c of the bucket 6 is set as the target surface G2.

With the present embodiment, the back surface 6c of the bucket 6 is set as the target surface G2 with respect to the reference surface G1, so that, when the bucket 6 is operated, the target surface G2 is changed to match the reference surface G1.

To be more specific, for example, when the bucket 6 is operated such that the position of the reference surface G1 and the position of a reference surface G1a match, the target surface G2 is changed to a target surface G2a, which is a plane having an angle θa with respect to the reference surface G1a.

Therefore, with the present embodiment, for example, when moving the teeth of the bucket 6 along the target surface G2a after moving the teeth of the bucket 6 along the target surface G2, the target surface can be changed simply by performing an operation to change the angle of the bucket 6.

In this way, according to the present embodiment, by setting a target surface, there is no need to configure data related to the design surface (target working surface) in advance before the operator boards the excavator 100, which saves time and resources required for configuration procedures.

Also, according to the present embodiment, the target surface can be changed while the operator stays in the cabin 10.

Note that the value of the set angle in the present embodiment may be determined by the controller 30 based on the attitude of the excavator 100.

To be more specific, for example, when the controller receives from the operator an operation that commands setting a target surface while the bucket 6 touches the plane that the teeth of the bucket 6 are in contact with, the controller 30 may use the angle that is currently formed between the back surface 6c of the bucket 6 and the plane that the teeth of the bucket 6 are in contact with, as the set angle, and setting the target surface.

In this case, the operator can configure the target surface by operating the bucket 6 without entering a set angle himself/herself.

FIG. 8 is a diagram that shows an example of a target surface setting screen. The guidance screen 41V1 shown in FIG. 8 is displayed on the display device D1, for example, when the excavator 100 is operated, such as when the gate lock is unlocked, when an operating device 26 (operating lever) is operated, and so forth.

As shown in FIG. 8, the guidance screen 41V1 includes a time display part 451, a rotation speed mode display part 452, a traveling mode display part 453, an attachment display part 454, an engine control state display part 455, a remaining urea water amount display part 456, a remaining fuel amount display part 457, a cooling water temperature display part 458, an engine operating time display part 459, a captured image display part 460, a work guidance display part 470, a configuration date display part 480, and an adjustment date display part 490. Images displayed in these parts are generated by the conversion process part 40a of the display device D1, from various data transmitted from the controller 30 and captured images transmitted from the camera as the space recognition device 70.

The time display part 451 displays the current time. In the example shown in FIG. 8, digital display is used, and the current time (10:05) is shown.

The rotation speed mode display part 452 displays an image of a rotation speed mode that is configured by an engine rotation speed adjustment dial. There are four rotation speed modes, for example, including, SP mode, H mode, A mode, and idling mode. In the example shown in FIG. 8, the symbol “SP,” which stands for SP mode, is displayed.

Note that the engine rotation speed adjustment dial may be provided in the cabin 10 of the excavator 100. The engine rotation speed adjustment dial is a dial for adjusting the engine's rotation speed and can, for example, switch the engine rotation speed incrementally. With the present embodiment, the engine rotation speed adjustment dial is provided so that the engine rotation speed can be switched in four steps: SP mode, H mode, A mode, and idling mode. The engine rotation speed adjustment dial sends data that shows the configuration of engine rotation speed, to the controller 30.

SP mode is the rotation speed mode selected when the operator wants to prioritize the amount of work, and uses the highest engine rotation speed. H mode is the rotation speed mode selected when the operator wants to have a balance between the amount of work and fuel efficiency, and uses the second highest engine rotation speed. A mode is the rotation speed mode selected when the operator wants to operate the excavator 100 with low noise while prioritizing fuel efficiency, and uses the third highest engine rotation speed. Idling mode is the rotation speed mode selected when the operator wants to place the engine in an idling state, and uses the lowest engine rotation speed. Then, the engine 11 is controlled to rotate at a certain rotation speed, that is, at the engine rotation speed of the rotation speed mode selected via the engine rotation speed adjustment dial.

The traveling mode display part 453 displays the traveling mode. The traveling mode represents the configuration of the traveling hydraulic motor using a variable displacement pump. For example, the traveling mode may be a low speed mode or a high speed mode. In low speed mode, a symbol that looks like a turtle is displayed; on the other hand, in high speed mode, a symbol that looks like a rabbit is displayed. In the example shown in FIG. 8, a turtle-like symbol is displayed, so that the operator can understand that the low speed mode is configured.

The attachment display part 454 displays an image that represents the attachment that is mounted. Various end attachments may be attached to the excavator 100, including the bucket 6, a rock jackhammer, a grapple, and a lifting magnet. The attachment display part 454 displays, for example, symbols that represent these end attachments and numbers that correspond to these attachments.

In the present embodiment, the bucket 6 is attached as an end attachment. As shown in FIG. 8, the attachment display part 454 is blank. If a rock jackhammer is attached as an end attachment, for example, a symbol that looks like a rock jackhammer is displayed in the attachment display part 454, along with a number that indicates the magnitude of output of the rock jackhammer.

The engine control state display part 455 displays the control state of the engine 11. In the example shown in FIG. 8, “auto deceleration/auto stop mode” is selected as the control state of the engine 11. Note that “auto deceleration/auto stop mode” refers to a state of control in which the engine rotation speed is automatically reduced and the engine 11 is automatically stopped, depending on the duration of the state in which the engine's load is low. Other control states in which the engine 11 may be placed include “auto deceleration mode,” “auto stop mode,” “manual deceleration mode,” and so forth.

The remaining urea water amount display part 456 displays an image of the remaining amount of urea water stored in the urea water tank. In the example shown in FIG. 8, a bar graph that shows the amount of currently remaining urea water is displayed. Note that the remaining amount of urea water is displayed based on data output from a urea water remaining amount sensor installed in the urea water tank.

The remaining fuel amount display part 457 displays the remaining amount of fuel stored in the fuel tank. In the example shown in FIG. 8, a bar graph that represents the amount of currently remaining fuel is displayed. Note that the amount of remaining fuel is displayed based on data output from a remaining fuel amount sensor installed in the fuel tank.

The cooling water temperature display part 458 displays the temperature of the engine cooling water. In the example shown in FIG. 8, a bar graph that represents the temperature of the engine cooling water is displayed. Note that the temperature of the engine cooling water is displayed based on data output from a water temperature sensor 11c provided in the engine 11.

The engine operating time display part 459 displays the cumulative operating time of the engine 11. In the example shown in FIG. 8, the cumulative operating time since the count was restarted by the driver is displayed together with the unit of measurement “hr (hour).” The engine operating time display part 459 displays the lifetime operating time of the entire excavator 100 such as the entire period since the excavator 100 was manufactured, or a partial operating time such as the period since the counting was restarted by the operator.

The captured image display part 460 displays the images captured by the cameras. In the example shown in FIG. 8, an image captured by the rear recognition sensor 70B, which serves as a rear camera, is displayed in the captured image display part 460. The captured image display part 460 may display images captured by the left recognition sensor 70L, which serves as a left camera, or images captured by the right recognition sensor 70R, which serves as a right camera.

Also, in the captured image display part 460, images captured by multiple cameras among the left camera, right camera, and rear camera may be displayed side by side. Furthermore, the captured image display part 460 may display a bird's-eye view image or the like, which is a composite of captured images taken by the left camera, right camera, and rear camera.

Note that each camera is installed such that a part of the cover 3a of the upper rotating body 3 is included in images captured by that camera. Since a part of the cover 3a is included in images that are displayed, the operator can easily learn the distance between the excavator 100 and the object displayed in the captured image display part 460.

The captured image display part 460 displays an image capturing device icon 461 that shows the orientation of the image capturing device 80 that captured the image being displayed. The image capturing device icon 461 includes an excavator icon 461a that represents a top view of the shape of the excavator 100, and a band-shaped direction indication icon 461b that represents the orientation of the image capturing device 80 that captured the image being displayed.

In the example shown in FIG. 8, the direction indication icon 461b is displayed below the excavator icon 461a (that is, opposite the attachment), and the captured image display part 460 displays an image of the rear of the excavator 100 captured by the rear camera 80B. For example, when an image captured by the right camera is displayed in the captured image display part 460, the direction indication icon 461b is displayed on the right side of the excavator icon 461a. Also, for example, when an image captured by the left camera is displayed in the captured image display part 460, the direction indication icon 461b is displayed on the left side of the excavator icon 461a.

For example, by pressing an image-changing switch provided in the cabin 10, the operator can switch the image displayed on the captured image display part 460 to an image captured by a different camera.

Note that, if the excavator 100 has no camera that serves as the space recognition device 70, different information may be presented without involving the captured image display part 460.

The work guidance display part 470 includes a position indication image 471 and a bucket image display field 472, and displays various information.

The position indication image 471 is a bar graph in which multiple bars are aligned vertically, and displays the distance from the working part of the attachment to the target surface.

In the present embodiment, one of the seven bars is displayed as a bucket position indication bar 471a (in FIG. 8, the third bar from the top), in a different color from the rest of the bars, depending on the distance from the working part of the bucket 6 to the target surface. The bucket position indication bar 471a indicates the current position of the working part of the attachment. Also, among the seven bars, the center bar 471b (in FIG. 8, the fourth bar from the top) indicates the target surface. For example, when the bucket position indication bar 471a overlaps the center bar 471b, this indicates that the working part of the current bucket 6 is located on the target surface. Note that the position indication image 471 may be composed of a larger number of bars such that the distance from the working part of the bucket 6 to the target surface can be displayed more accurately.

For example, when the distance from the working part of the bucket 6 to the target surface increases, a bar that is shown in a vertically higher position is displayed as the bucket position indication bar, in a different color from the rest of the bars. Also, when the distance from the working part of the bucket 6 to the target surface becomes smaller, a bar that is shown in a vertically lower position is displayed as the bucket position indication bar, in a different color from the rest of the bars. In this way, the bucket position indication bar is displayed to move up and down depending on the distance from the working part of the bucket 6 to the target surface. By looking at the position indication image 471, the operator can learn the distance from the working part of the bucket 6 to the target surface.

In the bucket image display field 472, information about the setting of the target surface is displayed. To be more specific, the bucket image display field 472 includes an image display field 473 and a set angle display field 474.

The image display field 473 schematically displays the relationship between the bucket 6 and the target surface. The set angle display field 474 displays the set angle that is entered from the input device 72.

In FIG. 8, the image display field 473 shows a state in which the back surface 6c of the bucket 6 is the reference surface G1, and a plane having an angle θa, which is the set angle, with respect to the reference surface G1, is set as the target surface G2. Also, the set angle display field 474 indicates that the set angle is configured to 30 degrees.

Therefore, the example of FIG. 8 makes it clear that the plane where the angle with respect to the back surface 6c of the bucket 6 is 30 degrees is set as the target surface G2. Note that, with the present embodiment, the set angle may be configured such that the back surface 6c of the bucket 6 and the target surface G2 are parallel to each other. In other words, with the present embodiment, the set angle may be configured to 0 degrees.

Furthermore, images 473a and 473b are displayed in the image display field 473. Images 473a and 473b show a state in which the target surface G2 is set and in which the bucket 6 can be moved along the target surface G2.

In other words, the images 473a and 473b are images for allowing the operator to understand that the working part of the bucket 6 moves along the target surface G2 in accordance with the operator's lever operation.

According to the present embodiment, as described above, a plane that forms a certain angle with respect to the back surface 6c of the bucket 6 can be set as a target surface by the operator's operation.

Note that the information displayed in the aforementioned rotation speed mode display part 452, traveling mode display part 453, attachment display part 454, engine control state display part 455, and image capturing device icon 461 is “information about the configuration of the excavator 100.” The information displayed in the remaining urea water amount display part 456, remaining fuel amount display part 457, cooling water temperature display part 458, and engine operating time display part 459 is “information about the state in which the excavator 100 operates.”

Also, the guidance screen 41V1 may include, other than the parts described above, a fuel efficiency display part that displays the efficiency of fuel, a hydraulic oil temperature display part that displays the temperature of hydraulic oil in the hydraulic oil tank, a warning display part that displays certain information when the parameters of the bucket 6 need to be adjusted, and so forth. When a predetermined period of time has elapsed since the parameters of the bucket 6 were adjusted, the warning display part displays information that indicates that the parameters of the bucket 6 need adjustment. By this means, when it is necessary to adjust the parameters of the bucket 6, the operator can be prevented from performing work such as excavation without adjusting the parameters of the bucket 6.

Also, in the example shown in FIG. 8, the remaining urea water amount display part 456, remaining fuel amount display part 457, and cooling water temperature display part 458 display bar graphs. However, these bar graphs may be replaced with needle graphs or the like, and the mode of display is not limited to that exemplified above with the present embodiment. Also, the arrangement of each field and so forth is not limited to the patterns described with the present embodiment.

Next, an example of display during operation of the excavator 100 will be described with reference to FIG. 9. FIG. 9 is a diagram that explains an example of display on a display device.

With the present embodiment, when the operator operates the bucket 6, the relationship between the operating bucket 6 and the target surface is displayed schematically in a bucket image display field 472 of the guidance screen 41V1.

In FIG. 9, the bucket image display field 472A includes an image display field 473A. In the image display field 473A, the position of the bucket 6 is different from the position shown in FIG. 8 due to the operator's operation.

In the image display field 473A, the back surface 6c (reference surface G1) of the bucket 6 and the target surface G2 in this case are displayed schematically. Also, in this case, the images 473a and 473b, which show the direction in which the working part of the bucket 6 moves in accordance with the operator's lever operation, are displayed.

With the present embodiment, the target surfaces G2 is set differently depending on the angle of the bucket 6 based on the current angle of the bucket 6 as a reference. Also, with the present embodiment, by showing the operator how the target surface changes following the movement of the bucket 6, it is possible to make the operator understand the state of the work.

Below, how the target surface changes in accordance with the operation of the bucket 6 will be described with reference to FIG. 10. FIG. 10 is a diagram that explains changes with the target surface.

FIG. 10 shows the operation when the excavator 100 according to the present embodiment excavates. In this case, the attitude of the excavator 100 changes depending on the operator's operation. In the following description, the attitude of the bucket angle indicated by the reference numeral 101 will be referred to as a first attitude, and the attitude of the bucket angle indicated by the reference numeral 102 will be referred to as a second attitude. Also, in the following description, the attitude of the bucket angle indicated by the reference numeral 103 will be referred to as a third attitude, and the attitude of the bucket angle indicated by the reference numeral 104 will be referred to as a fourth attitude.

Therefore, in FIG. 10, the attitude of the excavator 100 changes from the first attitude to the second attitude, third attitude, and fourth attitude.

In the first attitude, the controller 30 of the excavator 100 moves the teeth of the bucket 6 along the target surface G2a, which is at a set angle with respect to the back surface 6c of the bucket 6. In the second attitude, the controller 30 of the excavator 100 moves the teeth of the bucket 6 along the target surface G2b, which is at a set angle with respect to the back surface 6c of the bucket 6.

Similarly, in the third attitude, the controller 30 of the excavator 100 moves the teeth of the bucket 6 along the target surface G2c, which is at a set angle with respect to the back surface 6c of the bucket 6. In the fourth attitude, the controller 30 of the excavator 100 moves the teeth of the of the bucket 6 along the target surface G2d, which is at a set angle with respect to the back surface 6c of the bucket 6.

Note that, over the series of attitude changes, the boom 4 is controlled by the machine control function. To be more specific, boom command values for the boom 4 are generated based on the target surface and the speed of the arm 5, and control the operation of the boom 4.

Therefore, with the present embodiment, since the target surface changes depending on the angle of the bucket 6, the operator can perform work only by performing the arm-folding operation (in the first attitude to the third attitude) and the bucket-folding operation (in the fourth attitude).

Also, according to the present embodiment, every time the angle of the bucket 6 changes, the target surface is set to a certain angle with respect to the back surface of the bucket 6, so that the accuracy of work can be improved.

Also, with the present embodiment, the relationship between the back surface 6c of the bucket 6 and the target surface may be displayed schematically in the image display field 473A in FIG. 9 every time the angle of the bucket 6 changes.

In this case, the image display field 473 in FIG. 9 schematically displays the relationship between the back surface 6c of the bucket 6 and the target surface G2a when the attitude of the excavator 100 assumes the first attitude, and schematically displays the relationship between the back surface 6c of the bucket 6 and the target surface G2b when the attitude of the excavator 100 assumes the second attitude.

Furthermore, the image display field 473 in FIG. 9 schematically displays the relationship between the back surface 6c of the bucket 6 and the target surface G2c when the excavator 100 assumes the third attitude, and schematically displays the relationship between the back surface 6c of the bucket 6 and the target surface G2d when the excavator 100 assumes the fourth attitude.

Note that, according to the present embodiment, for example, if a design surface (target working surface) is set for the excavator 100 in advance, the design surface may be prioritized over the target surface as the position to which the working part of the bucket 6 is adjusted.

With reference to FIG. 9, a case will be described in which a plane G3 is set in advance as a design surface G3. In this case, the controller 30 controls the working part of the bucket 6 to reach the design surface G3 at the second attitude. When the controller 30 senses that the working part of the bucket 6 has reached the design surface G3, the controller 30 may control the operation of the working part of the bucket 6 to move along the design surface G3.

Also, with the present embodiment, when the controller 30 senses that the distance between the working part of the bucket 6 and the plane G3 is within a predetermined distance, the controller 30 may prioritize the design surface (plane G3) over the target surface G2.

As explained above, according to the present embodiment, there is no need to set a design surface before the excavator 100 starts working, so that the time and resources required for configuration procedures can be saved.

Also, with the present embodiment, the operation of the excavator 100 can be controlled by the machine control function even if no design surface is set.

Also, with the present embodiment, the set angle is entered through the input device 72, but this is by no means limiting. The set angle may be entered, for example, in a management device that manages the excavator 100 or an assisting device that assists the excavator 100, and the entered set angle may be sent to the excavator 100 to place the excavator 100 in that set angle. Also, as for the use of the set angle, the operator or the like may set a target surface by operating the arm 5 or boom 4 to bring the bucket 6 near the design surface, and then making fine adjustments to the angle of the bucket 6.

Although an embodiment for carrying out the present invention has been described above, the above-described details by no means limit the present invention, and various alterations and improvements can be made within the scope of the present invention.

Claims

1. An excavator comprising: a lower traveling body;an upper rotating body that is rotatably mounted on the lower traveling body;an attachment that is attached to the upper rotating body, and includes a boom, an arm, and a bucket; anda controller that is configured to set a target surface, the target surface being set differently depending on a current angle of the bucket serving as a reference angle in setting the target surface.

2. The excavator according to claim 1, wherein the controller is configured to: generate a primary command value for moving a primary element among the boom, the arm, and the bucket included in the attachment, in accordance with an operation by an operator; andgenerate a secondary command value for moving a secondary element among the boom, the arm, and the bucket included in the attachment, in accordance with movement of the primary element, such that a working part of the bucket moves along the target surface.

3. The excavator according to claim 1, wherein the target surface is a plane having a certain angle relative to a back surface of the bucket that serves as a reference plane.

4. The excavator according to claim 3, wherein the controller sets the target surface based on the certain angle and the angle of the bucket that is observed when an operation that commands setting of the target surface is received.

5. The excavator according to claim 3, wherein, when an angle of the bucket changes during control by the controller, the target surface is changed in accordance with a change of the angle of the bucket.

6. The excavator according to claim 3, wherein the controller causes a display device to display a screen for entering the certain angle.

7. The excavator according to claim 1, wherein, when the controller senses that a target working surface that is different from the target surface is set, and that a working part of the bucket is within a certain distance from the target working surface, the controller causes the working part of the bucket to move along the target working surface.