Excavator, control system for excavator, and remote operation system for excavator

Abstract

An excavator (100) includes: a lower traveling body (1); an upper rotating body (3) mounted on the lower traveling body (1); an attachment (AT) mounted on the upper rotating body (3); and an actuator configured to move the attachment (AT). The excavator (100) is configured such that movement of the actuator is controlled at a predetermined work site. The excavator (100) may also be configured such that the movement of actuator is prevented or substantially prevented at the predetermined work site.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an excavator, an excavator control system, and a remote excavator operation system.BACKGROUND ART

[0002] An existing excavator monitors its surroundings using cameras mounted on its upper rotating body (see, for example, patent document 1).RELATED-ART DOCUMENTPATENT DOCUMENT

[0003] Patent Document 1: Unexamined Japanese Patent Application Publication No. 2017-147759SUMMARY OF THE INVENTIONPROBLEM TO BE SOLVED BY THE INVENTION

[0004] However, the above excavator has a risk of requiring extra time to detect objects that are hidden by and behind the excavator's end attachment such as a bucket.

[0005] It is therefore desirable to provide an excavator that can prevent, more reliably, the excavator's attachment and objects around the attachment from coming into contact with each other.MEANS FOR SOLVING PROBLEM

[0006] The excavator according to an embodiment of the present disclosure includes: a lower traveling body; an upper rotating body mounted on the lower traveling body; an attachment mounted on the upper rotating body; and an actuator configured to move the attachment, and the excavator is configured such that movement of the actuator is controlled at a predetermined work site.ADVANTAGEOUS EFFECTS OF THE INVENTION

[0007] The above excavator can prevent, more reliably, the excavator's attachment and objects around the attachment from coming into contact with each other.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] [FIG. 1] FIG. 1 is a side view of an excavator according to an embodiment of the present disclosure; [FIG. 2] FIG. 2 is a top view of an excavator according to an embodiment of the present disclosure; [FIG. 3] FIG. 3 is a diagram showing an example structure of a hydraulic system mounted on an excavator; [FIG. 4] FIG. 4 is a diagram of a part of a hydraulic system related to the operation of an arm cylinder; [FIG. 5] FIG. 5 is a diagram showing an example structure of a discharge control function; [FIG. 6] FIG. 6 is a diagram for explaining an example of the contents of a reference table; [FIG. 7] FIG. 7 is a flowchart of an example of a movement limiting process; [FIG. 8] FIG. 8 is a diagram for explaining another example of the contents of a reference table; [FIG. 9] FIG. 9 is a perspective view of an excavator performing craning; [FIG. 10] FIG. 10 is a side view of an excavator performing deep excavation; [FIG. 11] FIG. 11 is a diagram showing an example of an operating state screen; [FIG. 12] FIG. 12 is a diagram showing another example of an operating state screen; and [FIG. 13] FIG. 13 is a schematic diagram showing an example structure of an excavator control system. EMBODIMENTS FOR CARRYING OUT THE INVENTION

[0009] First, an excavator 100 that serves as an excavating machine according to an embodiment of the present disclosure will be described with reference to FIG. 1 and FIG. 2. FIG. 1 is a side view of the excavator 100, and FIG. 2 is a top view of the excavator 100.

[0010] According to the present embodiment, a lower traveling body 1 of the excavator 100 includes crawlers 1C that serve as driven elements. The crawlers 1C are driven by drive hydraulic motors 2M mounted on the lower traveling body 1. However, the drive hydraulic motors 2M may be drive electric motors as well, which serve as electric actuators. To be more specific, the crawlers 1C include a left crawler 1CL and a right crawler 1CR. The left crawler 1CL is driven by a left drive hydraulic motor 2ML. The right crawler 1CR is driven by a right drive hydraulic motor 2MR. The lower traveling body 1 is driven by the crawlers 1C and therefore functions as a driven element.

[0011] An upper rotating body 3 is rotatably mounted on top of the lower traveling body 1 via a rotating mechanism 2. The rotating mechanism 2 serves as an element to be driven by a rotating hydraulic motor 2A mounted on the upper rotating body 3. However, the rotating hydraulic motor 2A may be a rotating generator that serves as an electric actuator. The upper rotating body 3 is driven by the rotating mechanism 2 and therefore functions as a driven element.

[0012] A boom 4 that serves as a driven element is attached to the upper rotating body 3. An arm 5 is attached to the tip of the boom 4 as a driven element. A bucket 6 is attached to the tip of the arm 5 as a driven element and as an end attachment. The end attachment is the member attached to the tip of the arm 5, and may be a breaker, a grapple, a lifting magnet, or the like. The boom 4, the arm 5, and the bucket 6 constitute an excavating attachment, which is an example of an attachment AT. The boom 4 is driven by a boom cylinder 7. The arm 5 is driven by an arm cylinder 8. The bucket 6 is driven by a bucket cylinder 9.

[0013] A boom angle sensor S1 is attached to the boom 4. An arm angle sensor S2 is attached to the arm 5. A bucket angle sensor S3 is attached to the bucket 6.

[0014] The boom angle sensor S1 detects the rotation angle of the boom 4. According to the present embodiment, the boom angle sensor S1 is an acceleration sensor that can detect the boom angle, which is the rotation angle of the boom 4 relative to the upper rotating body 3. For example, the boom angle is at a minimum when the boom 4 is brought to its lowest position, and increases as the boom 4 is raised upward.

[0015] The arm angle sensor S2 detects the rotation angle of the arm 5. According to the present embodiment, the arm angle sensor S2 is an acceleration sensor, and can detect the arm angle, which is the rotation angle of the arm 5 relative to the boom 4. For example, the arm angle is at a minimum when the arm 5 is folded completely, and increases as the arm 5 opens.

[0016] The bucket angle sensor S3 detects the rotation angle of the bucket 6. According to the present embodiment, the bucket angle sensor S3 is an acceleration sensor, and can detect the bucket angle, which is the rotation angle of the bucket 6 relative to the arm 5. For example, the bucket angle is at a minimum when the bucket 6 is folded completely, and increases as the bucket 6 opens.

[0017] Each of the boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3 may be, for example, a potentiometer using a variable resistor, a stroke sensor that detects the stroke of a corresponding hydraulic cylinder, a rotary encoder that detects the rotation angle about a linking pin, a gyro sensor, a combination of an acceleration sensor and a gyro sensor, and so on.

[0018] The upper rotating body 3 is provided with a cabin 10, which serves as a control room, and has a drive source such as an engine 11 mounted therein. The drive source may be a hydrogen-fueled engine or an electric motor as well. Also attached to the upper rotating body 3 are an exterior alarm 45A, an object detection device 70, a positioning device 85, a body inclination sensor S4, a rotating angular velocity sensor S5, and so forth. Inside the cabin 10, for example, an operating device 26, a controller 30, a display device 40, and an interior alarm 45B are provided. Note that, in this specification, for ease of understanding, the side of the upper rotating body 3 where the boom 4 is attached will be referred to as "front," and the side of the upper rotating body 3 where a counterweight is attached will be referred to as "rear."

[0019] The controller 30 is an example of a processing circuit that functions as a control device for controlling the excavator 100. According to the present embodiment, the controller 30 is structured as a computer with a CPU, RAM, NVRAM, ROM, and the like. For example, the controller 30 reads a program that is associated with a given function from the ROM, loads the program in the RAM, and causes the CPU to execute a corresponding process.

[0020] The display device 40 is configured to display image information. In the example illustrated, the display device 40 is an organic EL display and configured to present image information to the operator of the excavator 100.

[0021] The exterior alarm 45A is configured to output sounds to the outside of the cabin 10. In the example illustrated, the exterior alarm 45A is an exterior speaker and configured to output sounds to attract the attention of workers working around the excavator 100.

[0022] The interior alarm 45B is configured to produce sounds inside the cabin 10. In the example illustrated, the interior alarm 45B is an interior speaker and configured to output sounds to attract the attention of the operator who operates the excavator 100.

[0023] The object detection device 70 is configured to detect objects around the excavator 100. Such objects may include, for example, people, animals, vehicles, construction machines, buildings, holes, and so forth. The object detection device 70 is, for example, an ultrasonic sensor, a millimeter wave radar, an image-capturing device, or an infrared sensor. The image-capturing device may be, for example, a monocular camera, a stereo camera, a LIDAR (Light Detecting and Ranging), or a distance image sensor. According to the present embodiment, the object detection device 70 includes attachment cameras 70A attached to the attachment AT, a rear camera 70B attached to the rear end of the upper surface of the rotating body 3, a front camera 70F attached to the front end of the upper surface of the cabin 10, a left camera 70L attached to the left end of the upper surface of the rotating body 3, and a right camera 70R attached to the right end of the upper surface of the upper rotating body 3. In the example illustrated, the attachment cameras 70A include a first camera 70A1 attached to the bucket cylinder 9, a second camera 70A2 attached to the left side-surface of the arm 5, and a third camera 70A3 attached to the right side-surface of the arm 5. Note that the attachment cameras 70A may be any one or two of the first camera 70A1 to the third camera 70A3, and may include cameras attached to the back or outer surface of the arm 5, or include cameras attached to the belly or inner surface of the arm 5. The attachment cameras 70A may be omitted as well.

[0024] The object detection device 70 may be configured to detect a predetermined object (for example, a person) in a predetermined range around the excavator 100. For example, the object detection device 70 may be configured to distinguish between human and non-human objects.

[0025] The positioning device 85 is configured to measure the location of the excavator 100. According to the present embodiment, the positioning device 85 is a GNSS receiver incorporating an electronic compass. The positioning device 85 calculates and outputs the latitude, longitude, and altitude of the excavator 100 based on GNSS signals received. Furthermore, the positioning device 85 calculates and outputs the orientation of the excavator 100.

[0026] The body inclination sensor S4 is configured to detect the inclination of the upper rotating body 3 relative to a predetermined plane / surface. According to the present embodiment, the body inclination sensor S4 is an acceleration sensor that detects the tilting angle of the upper rotating body 3 about the front-to-back axis and about the left-to-right axis of the upper rotating body 3, relative to the horizontal plane. The front-to-rear axis and the left-to-right axis of the upper rotating body 3 are, for example, perpendicular to each other and pass through the excavator's center point, which is a point on the rotation axis of the excavator 100.

[0027] The rotating angular velocity sensor S5 is configured to detect the rotating angular velocity of the upper rotating body 3. According to the present embodiment, the rotating angular velocity sensor S5 is a gyro sensor. The rotating angular velocity sensor S5 may be a resolver, a rotary encoder, and so forth. The rotating angular velocity sensor S5 may be configured to output at least one of the rotating speed and the rotating angle. In this case, at least one of the rotating speed and the rotating angle may be calculated from the rotating angular velocity.

[0028] Hereinafter, any combination of the boom angle sensor S1, arm angle sensor S2, bucket angle sensor S3, body inclination sensor S4, and rotating angular velocity sensor S5 will be collectively referred to as an "attitude sensor."

[0029] 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.

[0030] 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.

[0031] In FIG. 3, the hydraulic system is structured such that hydraulic oil is circulated from the main pumps 14 driven by the engine 11, to a hydraulic oil tank, via center bypass pipelines CB or parallel pipelines PC.

[0032] The engine 11 serves as 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 engine 11's outputs shafts are connected to the respective input shafts of the main pumps 14 and the pilot pump 15.

[0033] 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 swashplate variable displacement hydraulic pumps.

[0034] The pump regulators 13 are structured to control the amount of discharge from the main pumps 14. With the present embodiment, the pump regulators 13 control the amount of discharge (the volume of displacement) 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.

[0035] The pilot pump 15 is structured to supply hydraulic oil to the hydraulic control mechanism, including the operating devices 26, via pilot lines. With the present embodiment, the pilot pump 15 is a fixed displacement hydraulic pump. However, the pilot pump 15 may be omitted. In that case, the function of the pilot pump 15 may be imparted to the main pumps 14. That is, in addition the function to supply hydraulic oil to the control valve unit 17, the main pumps 14 may also have a function to reduce the pressure of hydraulic oil using an aperture and the like, and then supply the hydraulic oil to the operating devices 26, proportional valves 31 (see FIG. 4), and so forth.

[0036] The control valve unit 17 is a hydraulic control device that controls the hydraulic system of 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. The control valves 176 include a control valve 176L and a control valve 176R. The control valve unit 17 can supply the hydraulic oil discharged from the main pumps 14 to one or more selected 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 the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, the left drive hydraulic motor 2ML, the right drive hydraulic motor 2MR, and a rotating hydraulic motor 2A.

[0037] The operating devices 26 are structured to allow the operator to operate the actuators. The actuators may be hydraulic actuators or electric actuators. With the present embodiment, the operating devices 26 supply the hydraulic oil discharged from the pilot pump 15, 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 is adjusted to be suitable for each corresponding hydraulic actuator, depending on the direction of operation and the amount of operation made on the operating device 26 associated with each hydraulic actuator.

[0038] 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.

[0039] The operation sensors 29 are structured to detect the details of operations made on the operating devices 26 by the operator. With the present embodiment, the operation sensors 29 detect the direction of lever or pedal operation and the amount of lever or pedal operation made on each actuator's corresponding operating devices 26, in angles, and output the detected values to the controller 30. The details of operations made on the operating devices 26 may be detected using sensors other than angle sensors.

[0040] 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 through a left center bypass pipeline CBL or a left parallel pipeline PCL, to the hydraulic oil tank. The right main pump 14R circulates the hydraulic oil through a right center bypass pipeline CBR or a right parallel pipeline PCR to the hydraulic oil tank.

[0041] The left center bypass pipeline CBL 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 CBR is a hydraulic oil line that passes through the control valves 172, 174, 175R, and 176R positioned in the control valve unit 17.

[0042] 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 drive hydraulic motor 2ML and the hydraulic oil discharged from the left drive hydraulic motor 2ML is exhausted to the hydraulic oil tank.

[0043] 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 drive hydraulic motor 2MR and the hydraulic oil discharged from the right drive hydraulic motor 2MR is exhausted to the hydraulic oil tank.

[0044] 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 rotating hydraulic motor 2A and the hydraulic oil discharged from the rotating hydraulic motor 2A is exhausted to the hydraulic oil tank.

[0045] 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 exhausted to the hydraulic oil tank.

[0046] The control valve 175L 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 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 exhausted to the hydraulic oil tank.

[0047] 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 exhausted to the hydraulic oil tank.

[0048] 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 exhausted to the hydraulic oil tank.

[0049] The left parallel pipeline PCL is a hydraulic oil line that runs parallel to the left center bypass pipeline CBL. When the flow of hydraulic oil passing in the left center bypass pipeline CBL is limited or blocked by any of the control valves 171, 173, and 175L, the left parallel pipeline PCL can supply hydraulic oil to more downstream control valves. The right parallel pipeline PCR is a hydraulic oil line that runs parallel to the right center bypass pipeline CBR. When the flow of hydraulic oil passing in the right center bypass pipeline CBR is limited or blocked by any of the control valves 172, 174, and 175R, the right parallel pipeline PCR can supply hydraulic oil to more downstream control valves.

[0050] The pump regulators 13 include a left pump regulator 13L and a right pump regulator 13R. The left pump regulator 13L controls the amount of discharge (the volume of displacement) by 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 pump regulator 13L reduces the amount of discharge (the volume of displacement) by the left main pump 14L by adjusting the tilting angle of the swashplate of the left main pump 14L in accordance with the increase of the discharge pressure of the left main pump 14L, for example. The same applies to the right pump regulator 13R. This is to prevent the absorbed power (absorbed horsepower) of each main pump 14, which is determined by the product of the discharge pressure and the amount of discharge, from exceeding the output power (output horse power) of the engine 11.

[0051] The operating devices 26 include a left operating lever 26L, a right operating lever 26R, and drive levers 26D. The drive levers 26D include a left drive lever 26DL and a right drive lever 26DR.

[0052] The left operating lever 26L is used to make rotating operations and to operate the arm 5. When the left operating lever 26L is operated in the front-rear direction, a control pressure to match the amount in which the lever is operated is introduced to the pilot ports of corresponding control valves 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 in which the lever is operated is introduced to the pilot ports of corresponding control valves 173, by using the hydraulic oil discharged from the pilot pump 15.

[0053] To be more specific, when the left operating lever 26L is operated in an 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 an arm-opening direction, hydraulic oil is introduced to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R. Also, when the left operating lever 26L is operated in a 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 a right-rotating direction, hydraulic oil is introduced to the right pilot port of the control valve 173.

[0054] The right operating lever 26R is used to operate the boom 4 and the bucket 6. When the right operating lever 26R is operated in the front-rear direction, a control pressure to match the amount in which the lever is operated is introduced to a corresponding control valve 175's pilot port, 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 in which the lever is operated is introduced to a corresponding control valve 174's pilot port, by using the hydraulic oil discharged from the pilot pump 15.

[0055] To be more specific, when the right operating lever 26R is operated in a 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 a boom-raising direction, hydraulic oil is introduced to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R. Also, when the right operating lever 26R is operated in a 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 a bucket-opening direction, hydraulic oil is introduced to the left pilot port of the control valve 174.

[0056] The drive levers 26D are used to operate the crawlers 1C. To be more specific, the left drive lever 26DL is used to operate the left crawler 1CL. The left drive lever 26DL may also be structured to work in conjunction with the left drive pedal. When the left drive lever 26DL is operated in the front-rear direction, a control pressure to match the amount in which the lever is operated is introduced to a corresponding pilot port of the control valve 171, by using the hydraulic oil discharged from the pilot pump 15. The right drive lever 26DR is used to operate the right crawler 1CR. The right drive lever 26DR may also be structured to work in conjunction with the right drive pedal. When the right drive lever 26DR is operated in the front-rear direction, a control pressure to match the amount in which the lever is operated is introduced to a corresponding pilot port of the control valve 172, by using the hydraulic oil discharged from the pilot pump 15.

[0057] The discharge pressure sensors 28 include a left discharge pressure sensor 28L and a right discharge pressure sensor 28R. The left 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 right discharge pressure sensor 28R.

[0058] The operation sensors 29 include operation sensors 29LA, 29LB, 29RA, 29RB, 29DL, and 29DR. The operation sensor 29LA detects the details of operations that the operator performs on the left operating lever 26L in the front-rear direction, and outputs the detected values, in angles, to the controller 30. The details of operations here include, for example, the direction in which the lever is operated, the amount in which the lever is operated (the angle at which the lever is operated), and so on. Similarly, the operation sensor 29LB detects the details of operations that the operator performs on the left operating lever 26L in the left-right direction, and outputs the detected values, in angles, to the controller 30. 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, in angles, to the controller 30. The operation sensor 29RB detects the details of operations that the operator performs on the right operating lever 26R in the left-right direction, and outputs the detected values, in angles, to the controller 30. The operation sensor 29DL detects the details of operations that the operator performs on the left operating lever 26DL in the front-rear direction, and outputs the detected values, in angles, to the controller 30. The operation sensor 29DR detects the details of operations that the operator performs on the right operating lever 26DR in the front-rear direction, and outputs the detected values, in angles, to the controller 30.

[0059] The controller 30 receives the outputs of the operation sensors 29, outputs control commands to the pump regulators 13 on an as-needed basis, and changes the amount of discharge from the main pumps 14.

[0060] Now, negative control using apertures 18 and control pressure sensors 19 will be described. The apertures 18 include a left aperture 18L and a right aperture 18R. The control pressure sensors 19 include a left control pressure sensor 19L and a right control pressure sensor 19R.

[0061] On the left center bypass pipeline CBL, the left aperture 18L is positioned between the most downstream control valve 176L and the hydraulic oil tank. The flow of hydraulic oil discharged from the left main pump 14L is therefore limited by means of the left aperture 18L. The left aperture 18L, then, generates a control pressure for controlling the left pump 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. The controller 30 decreases the amount of discharge from the left main pump 14L when this control pressure increases, and increases the amount of discharge from the left main pump 14L when this control pressure decreases. The amount of discharge from the right main pump 14R is controlled likewise.

[0062] To be more specific, as shown in FIG. 3, in a standby state in which none of the hydraulic actuators in the excavator 100 is operated, hydraulic oil discharged from the left main pump 14L passes through the left center bypass pipeline CBL and reaches the left aperture 18L. Then, the flow of hydraulic oil discharged from the left main pump 14L increases the control pressure that is produced upstream of the left aperture 18L. As a result of this, the controller 30 reduces the amount of discharge from the left main pump 14L to the minimum possible amount of discharge, and prevents or substantially prevents pressure loss (pumping loss) from being produced when the discharged hydraulic oil passes through left center bypass pipeline CBL. 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 operated, via the control valve corresponding to the hydraulic actuator operated. By means of the flow of hydraulic oil discharged from the left main pump 14L thus, the amount of hydraulic oil that reaches the left aperture 18L decreases or vanishes, thus lowering the control pressure produced upstream of the left aperture 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 works. Note that the controller 30 likewise controls the amount of discharge from the right main pump 14R.

[0063] Structured as described above, the hydraulic system shown in FIG. 3 can prevent or substantially prevent the main pumps 14 from wasting energy while in standby state. The waste of energy here 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 necessary and sufficient hydraulic oil from the main pumps 14 to the hydraulic actuator to be started.

[0064] The control valve 60 is configured to switch each operating device 26 between an activated state and a deactivated state. When an operating device 26 is in the activated state, the operator can operate the operating device 26 and move a driven element associated with the operating device. If, on the other hand, the operating device 26 is in the deactivated state, the driven element associated with the operating device 26 cannot be moved even if the operator operates the operating device 26.

[0065] According to the present embodiment, the control valve 60 is a solenoid valve that can switch between a connected state and a disconnected state of the pilot line CD 1 that connects between the pilot pump 15 and the operating devices 26. To be more specific, the control valve 60 is configured to switch between a connected state and a disconnected state of the pilot line CD1 based on commands from the controller 30.

[0066] The control valve 60 may be configured to operate in conjunction with a gate-lock lever (not shown) . To be more specific, the control valve 60 may be configured to block the pilot line CD1 when the gate-lock lever is pressed, and to open the pilot line CD1 when the gate-lock lever is raised. However, the control valve 60 may be a solenoid valve other than a solenoid valve that can switch between the connected state and the disconnected state of the pilot line CD1 in conjunction with the gate-lock lever.

[0067] 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. 4. FIG. 4 is a diagram extracting a part of the hydraulic system. To be more specific, FIG. 4 is a diagram that extracts a part in the hydraulic system that relates to the operations of the arm cylinder 8. Note that, although the following description given with reference to FIG. 4 relates to the operations of the arm cylinder 8, the same description may be applied to the operations of other actuators as well, such as the boom cylinder 7, the bucket cylinder 9, the rotating hydraulic motor 2A, the left drive hydraulic motor 2ML, the right drive hydraulic motor 2MR, and so forth.

[0068] As shown in FIG. 4, the hydraulic system includes proportional valves 31. The proportional valves 31 include proportional valves 31AL and 31AR.

[0069] The proportional valves 31 function as control valves for controlling machines. The proportional valves 31 are positioned in pipelines that connect 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 in the pipelines can be changed. With the present embodiment, the proportional valves 31 work based on control commands from the controller 30. Consequently, regardless of whether or not the operator operates the operating devices 26, the controller 30 can still supply the hydraulic oil discharged from the pilot pumps 15 to corresponding control valves' pilot ports 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 corresponding control valves' pilot ports.

[0070] By means of this structure, when a specific operating device 26 is not being operated, the controller 30 can still run the hydraulic actuator associated with that specific operating device 26. Also, 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.

[0071] For example, as shown in FIG. 4, 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 to match the operation of the left operating lever 26L in the front-rear direction, to the 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 a direction to fold the arm (rear direction), a pilot pressure to match the amount of that lever operation is applied to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R. Also, when the left operating lever 26L is operated in a direction to open the arm (front direction), a pilot pressure to match the amount of that lever operation is applied to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R.

[0072] The operating devices 26 are provided with a switch SW1. According to the present embodiment, 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 other positions in the cabin 10.

[0073] The operation sensor 29LA detects the details of operations that the operator performs on the left operating lever 26L in the front-rear direction, and outputs the detected values to the controller 30.

[0074] The proportional valve 31AL works based on control commands (current commands) output from the controller 30. Then, the proportional valve 31AL adjusts the pilot pressure caused by the hydraulic oil introduced from the pilot pumps 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the proportional valve 31AL. The proportional valve 31AR works based on control commands (current commands) output from the controller 30. Then, the proportional valve 31AL adjusts the pilot pressure caused by the hydraulic oil introduced from the pilot pumps 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the proportional valve 31AR. The proportional valve 31AL can adjust the pilot pressure such that the control valve 176L and the control valve 176R can be stopped at any valve position. Similarly, the proportional valve 31AR can adjust the pilot pressure such that the control valve 176L and the control valve 176R can be stopped at any valve position.

[0075] Structured and configured thus, 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 the left pilot port of the control valve 176R, via the proportional valve 31AL, in accordance with an arm-folding operation by the operator. Also, regardless of whether or not the operator performs an arm-folding operation, the controller 30 can still supply the hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the proportional valve 31AL. That is, the controller 30 can fold the arm 5 either in accordance with an arm-folding operation by the operator or regardless of whether or not the operator performs an arm-folding operation.

[0076] 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 the right pilot port of the control valve 176R, via the proportional valve 31AR, in accordance with an arm-opening operation by the operator. Also, regardless of whether or not the operator performs an arm-opening operation, 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 the right pilot port of the control valve 176R, via the proportional valve 31AR. That is, the controller 30 can open the arm 5 either in accordance with an arm-opening operation by the operator or regardless of whether or not the operator performs an arm-opening operation.

[0077] Also, given this structure, when the operator is performing an arm-folding operation, the controller 30 can still reduce the pilot pressure that acts on the closing pilot ports of the control valves 176 (the left pilot ports of the control valve 176L and 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.

[0078] Alternatively, 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 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 pilot ports of the control valves 176, and bring the control valves 176 back to their neutral positions, thereby forcing 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.

[0079] Also, although description with reference to the drawings will be omitted, this also applies: when forcing a boom-lowering operation of the boom 4 operation to a stop while the operator is performing a boom-raising operation; when forcing an operation of the bucket 6 to a stop while the operator is performing a bucket-folding operation or a bucket-opening operation; and when forcing a rotation of the upper rotating body 3 to a stop while the operator is performing a rotating operation. The same applies to the case in which a drive operation of the lower traveling body 1 is forced to a stop while the operator is performing a drive operation.

[0080] Also, although the above description has illustrated electric operating levers as example of operating devices 26, hydraulic operating levers may be used instead of electric operating levers as well. In this case, the amount of operations on the hydraulic operating levers may be detected in angles by an angle sensor, and input to the controller 30. Also, solenoid valves may be positioned between the hydraulic operating levers that serve as operating devices 26 and the pilot ports of the control valves. The solenoid valves are configured to work based on electric signals from the controller 30. By means of this structure and configuration, when a hydraulic operating lever that serves as an operating device 26 is operated manually, the operating device 26 can increase or decreases the pilot pressure according to the amount in which the lever is operated, thus allowing each control valve to move. Also, the control valves may be solenoid spool valves. In this case, the solenoid spool valves work in accordance with electric signals that are transmitted from the controller 30 based on the amount in which each electric operating lever is operated.

[0081] Next, with reference to FIG. 5, an example of the function of the controller 30 to control the amount of discharge from the main pumps 14 (hereinafter referred to as "discharge control function") will be described. FIG. 5 shows an example structure of the controller 30 that implements the discharge control function. According to the present embodiment, the controller 30 includes a power control part 30A, an energy-saving control part 30B, a minimum value selection part 30C, a maximum value setting part 30D, and a current command output part 30E.

[0082] The power control part 30A is a control part where power control is implemented, which is one function to control the amount of discharge of the main pumps 14. The power control part 30A is configured such that, given an amount of discharge Q, a command value Qd is derived based on the discharge pressure Pd of a corresponding main pump 14. The amount of discharge Q is, for example, the volume of displacement, which is the amount of hydraulic oil discharged by a main pump 14 when the rotating shaft associated with the main pump 14 rotates once. However, the amount of discharge Q may be the amount of hydraulic oil discharged from a main pump 14 per unit time (for example, one minute). Power control is a function to adjust the amount of discharge of a main pump 14. The absorbed power (absorbed horsepower) of a main pump 14, which is the product of the amount of discharge and the discharge pressure, is less than or equal to the output power (output horsepower) of the engine 11. According to the present embodiment, the power control part 30A obtains a discharge pressure Pd output by the discharge pressure sensor 28. Then, the power control part 30A looks up a reference table and finds a command value Qd that corresponds to the obtained discharge pressure Pd. The reference table is associated with PQ diagrams and shows the relationships between the maximum allowable absorbed power (for example, the maximum allowable absorbed horsepower), the discharge pressure Pd, and the command value Qd of the main pump 14 in a referable manner. The reference table is stored in advance in a non-volatile memory device. The power control part 30A can identify a unique command value Qd by, for example, looking up the reference table by using a preset maximum allowable absorbed horsepower and discharge pressure Pd of the main pump 14, output by the discharge pressure sensor 28, as search keys.

[0083] The energy-saving control part 30B is a control part where negative control is implemented, which is one function to control the amount of discharge of the main pumps 14. The energy-saving control part 30B is configured to derive a command value Qn for the amount of discharge, based on the control pressure Pn. According to the present embodiment, the energy-saving control part 30B obtains a control pressure Pn output by the control pressure sensor 19. Then, the energy-saving control part 30B looks up a reference table and finds a command value Qn that corresponds to the obtained control pressure Pn. The reference table holds the relationship (flow-rate control characteristics) between the control pressure Pn and the command value Qn in a referable manner. The reference table is stored in advance in a non-volatile memory device.

[0084] The minimum value selection part 30C is configured to select and output the minimum value from among multiple input values. According to the present embodiment, the minimum value selection part 30C is configured to output the smaller one of the command value Qd and the command value Qn as a final command value Qf.

[0085] Typically, the command value Qn derived by the energy-saving control part 30B is selected by the minimum value selection part 30C when a relatively low-load job such as finishing, leveling, or driving is performed. That is, the command value Qn is selected when a low-load job is performed. On the other hand, typically, the command value Qd derived by the power control part 30A is selected by the minimum value selection part 30C when a relatively high-load job such as excavation is performed. That is, the command value Qd is selected when a high-load job is performed. In this way, the command value Qd selected by the minimum value selection part 30C determines whether the main pump 14 is controlled based on a job's low-load characteristics or based on a job's high-load characteristics.

[0086] The maximum value setting part 30D is configured to output the maximum command value Qmax. The maximum command value Qmax corresponds to the maximum amount of discharge of the main pump 14. According to the present embodiment, the maximum value setting part 30D is configured to output a maximum command value Qmax that is stored in advance in a non-volatile memory device or the like, to the current command output part 30E.

[0087] The current command output part 30E is configured to output the current command to the corresponding pump regulator 13. According to the present embodiment, the current command output part 30E outputs, to the pump regulators 13, a current command I, derived based on the final command value Qf output from the minimum value selection part 30C and the maximum command value Qmax output from the maximum value setting part 30D. Note that the current command output part 30E may output a current command I that is derived based on the final command value Qf, to the pump regulator 13. In this case, the maximum value setting part 30D may be omitted.

[0088] In this manner, the controller 30 controls the amount of discharge of the main pumps 14. The example illustrated above assumes that the controller 30 controls the amount of discharge of the left main pump 14L and the amount of discharge of the right main pump 14R separately. To be more specific, the controller 30 derives a current command for the left pump regulator 13L based on the discharge pressure of the left main pump 14L, which is detected by the left discharge pressure sensor 28L, and based on the control pressure, which is the pressure of hydraulic oil in the left center bypass pipeline CBL detected by the left control pressure sensor 19L. Then, the controller 30 outputs a current command to the left pump regulator 13L, thereby controlling the amount of discharge of the left main pump (14L). Also, the controller 30 derives a current command for the right pump regulator 13R based on the discharge pressure of the right main pump 14R, which is detected by the right discharge pressure sensor 28R, and based on the control pressure, which is the pressure of hydraulic oil in the right center bypass pipeline CBR detected by the right control pressure sensor 19R. Then, the controller 30 outputs the current command to the right pump regulator 13R, thereby controlling the amount of discharge of the right main pump 14R.

[0089] Next, with reference to FIG. 6, an example of the contents of a reference table that the energy-saving control part 30B looks up will be described. FIG. 6 is a diagram showing an example of the contents of a reference table, to be more specific, examples of relationships (flow-rate control characteristics) between the control pressure Pn and the command value Qn. To be more specific, in FIG. 6, the horizontal axis is the control pressure Pn detected by the control pressure sensor 19, and the vertical axis is the command value Qn. Each polyline includes a gradient line GL and shows the relationship between the command value Qn and the control pressure Pn. The command value Qn corresponds to the target amount of discharge of the main pumps 14. The controller 30 controls the pump regulators 13 such that the actual amount of discharge Q of the main pumps 14 becomes the target amount of discharge. The reference table represented by FIG. 6 is used to control the amount of discharge of the left main pump 14L and the amount of discharge of the right main pump 14R. When controlling the amount of discharge of the left main pump 14L, the horizontal axis in FIG. 6 is the control pressure detected by the left control pressure sensor 19L. The vertical axis in FIG. 6 is the command value for the amount of discharge of the left main pump 14L. Similarly, when controlling the amount of discharge of the right main pump 14R, the horizontal axis in FIG. 6 is the control pressure detected by the right control pressure sensor 19R. The vertical axis in FIG. 6 is the command value for the amount of discharge of the right main pump 14R.

[0090] To be more specific, FIG. 6 is a diagram showing the contents of the reference table to be looked up when the left operating lever 26L is operated in an arm-opening direction. In FIG. 6, the solid line shows the relationship (flow-rate control characteristics) between the control pressure Pn and the command value Qn when the left operating lever 26L is operated slightly. A lever is operated "slightly" when the amount of lever operation is less than 20%. Assuming that the amount of operation is 0% when the left operating lever 26L is at the neutral position and that the amount of lever operation is 100% when the left operating lever 26L is in the maximum tilt position, in FIG. 6, the dashed line shows the relationship (flow-rate control characteristics) between the control pressure Pn and the command value Qn when the left operating lever 26L is operated in a half-lever operation. "A half-lever operation" refers to, for example, an operation in which the amount of lever operation is greater than or equal to 20%, and less than 80%. Similarly, in FIG. 6, the dashed-and-dotted line shows the relationship (flow-rate control characteristics) between the control pressure Pn and the command value Qn when the left operating lever 26L is operated in a full-lever operation. "A full-lever operation" refers to, for example, an operation in which the amount of operation is 80% or more.

[0091] According to the present embodiment, the energy-saving control part 30B is configured to derive a command value Qn that corresponds to a control pressure Pn, based on a gradient line GL that extends between an uppermost point A and a lowermost point B.

[0092] The uppermost point A is the point that marks the upper end of the gradient line GL and is represented by a maximum command value Qmax and a first set pressure Px. The maximum command value Qmax is the upper limit of command values used in negative control. The maximum command value Qmax is, for example, a setting value that corresponds to a swashplate tilting angle of a main pump 14 that is a predetermined angle smaller than the maximum swashplate tilting angle. The first set pressure Px is a setting value that is set regardless of the amount of lever operation when the left operating lever 26L is operated in an arm-opening direction. Note that, in the example illustrated in FIG. 6, the amount of lever operation when the left operating lever 26L is operated in an arm-opening direction is the tilting angle (rotation angle) of the left operating lever 26L, determined based on the left operating lever 26L at the neutral position, and detected by an operation sensor 29LA, which serves as an angle sensor. However, the amount of lever operation when the left operating lever 26L is operated in an arm-opening direction may be detected by a device other than an angle sensor, such as a pressure sensor, an acceleration sensor, an angular velocity sensor, a resolver, a voltmeter, or an ammeter.

[0093] The lowermost point B is the point that marks the lower end of the gradient line GL and is represented by a minimum command value Qmin and a second setting pressure Py. The minimum command value Qmin is the lower limit of command values used in negative control. The minimum command value Qmin is, for example, a setting value that corresponds to a swashplate tilting angle of a main pump 14 that is a predetermined angle larger than the minimum swashplate tilting angle (for example, a swashplate tilting angle corresponding to the standby flow rate). The second setting pressure Py is a value that is set regardless of the amount of lever operation when the left operating lever 26L is operated in an arm-opening direction. The second setting pressure Py corresponds to, for example, the control pressure when hydraulic oil passes through the aperture 18 at the standby flow rate.

[0094] In the example illustrated in FIG. 6, the energy-saving control part 30B is configured to adjust the relationship (flow-rate control characteristics) between the control pressure Pn and the command value Qn by changing the position of the uppermost point A in the vertical-axis direction, that is, by changing the maximum command value Qmax.

[0095] The energy-saving control part 30B changes the position of the uppermost point A when the lever is operated slightly, when the lever is operated in a half-lever operation, and when the lever is operated in a full-lever operation. As a result of this, the energy-saving control part 30B adjusts the relationship (flow-rate control characteristics) between the control pressure Pn and the command value Qn to suit the state of the excavator 100 in each state. In the example illustrated in FIG. 6, the position of the uppermost point A is changed in three steps: when the lever is operated slightly; when the lever is operated in a half-lever operation; and when a lever is operated in a full-lever operation. The energy-saving control part 30B may also be configured such that, when the left operating lever 26L is operated in an arm-opening direction, the position of the uppermost point A is changed in two steps, or in four or more steps, depending on the amount in which the lever is operated. The energy-saving control part 30B may also be configured such that, when the left operating lever 26L is operated in an arm-opening direction, the position of the uppermost point A is changed steplessly depending on the amount in which the lever is operated. Alternatively, the energy-saving control part 30B may be configured such that the position of the uppermost point A is kept unchanged even if the amount of lever operation changes.

[0096] To be more specific, the energy-saving control part 30B is configured such that, as represented by the solid line in FIG. 6, when the lever is operated slightly, the uppermost point A is the uppermost point A1 (the point when the maximum command value Qmax is the setting value Qmax1) and the gradient line GL is the gradient line GL1.

[0097] Also, the energy-saving control part 30B is configured such that, as represented by the dashed line in FIG. 6, when the lever is operated in a half-lever operation, the uppermost point A is the uppermost point A2 (the point when the maximum command value Qmax is the setting value Qmax2) and the gradient line GL is the gradient line GL2. Also, the energy-saving control part 30B is configured such that, as represented by the dashed-and-dotted line in FIG. 6, when the lever is operated in a full-lever operation, the uppermost point A is the uppermost point A3 (the point when the maximum command value Qmax is the setting value Qmax3) and the gradient line GL is the gradient line GL3. Note that the setting value Qmax3 may be, for example, a setting value that corresponds to the maximum swashplate tilting angle of the main pump 14.

[0098] In this way, the position of the uppermost point A in the vertical-axis direction is changed according to the amount of the left operating lever 26L's operation in an arm-opening direction. As a result of this, the energy-saving control part 30B can prevent or substantially prevent the amount of hydraulic oil that flows into the arm cylinder 8 from being unstable during the arm-opening operation. When the amount of hydraulic oil is unstable, the operator is shaken back and forth, which makes it difficult for him / her to perform the arm-opening operation in a stable way, and which then makes the amount of hydraulic oil to flow into the arm cylinder 8 even more unstable. In some cases, the operator might cause "hunting," which makes the number of rotations of the engine 11 per unit time unstable. The energy-saving control part 30B can prevent or substantially prevent problems such as hunting from occurring. In this way, the energy-saving control part 30B can improve the operability of the arm 5.

[0099] For example, to start an arm-opening operation in standby state, the amount of hydraulic oil that passes through the aperture 18 decreases while the left operating lever 26L is operated in an arm-opening direction. This is because most of the hydraulic oil discharged from the main pump 14 is supplied to the arm cylinder 8. The standby state refers to the state of the excavator 100 in which, for example, the engine 11 is running but no operating device 26 is operated.

[0100] When hydraulic oil is supplied to the arm cylinder 8 and the amount of hydraulic oil that passes through the aperture 18 decreases, the control pressure Pn (negative control pressure) also decreases, and the command value Qn increases as shown in FIG. 6. If the gradient line GL is fixed to the gradient line GL3, the command value Qn increases at a greater rate than when the gradient line GL is fixed to the gradient line GL1, and the command value Qn reaches a maximum command value Qmax (setting value Qmax3) that is greater than the maximum command value Qmax (setting value Qmax1) for the gradient line GL1. When the amount in which the left operating lever 26L is operated increases, the rate of increase in the amount of discharge from the main pump 14 also becomes excessively large, which might make the operator unable to perform the arm-opening operation in a stable way. This is because the excavator 100 shakes back and forth. This shake may cause the operator sitting in the cabin 10 of the excavator 100 to rock back and forth, adversely affecting the operator's operation of the operating device 26.

[0101] On the other hand, when the gradient line GL1 is used as the gradient line GL that corresponds to the amount of the left operating lever 26L's operation (slight operation) when an arm-opening operation is started, the upper limit of the command value Qn is limited to the setting value Qmax1, which is smaller than the setting value Qmax3. Therefore, the rate of increase in the amount of discharge from the main pump 14 accompanying an increase in the amount of the left operating lever 26L's operation is kept low compared to when the gradient line GL3 is used as the gradient line GL. As a result of this, the shake of the excavator 100 in the front-rear direction when an arm-opening operation is started is mitigated, so that the operator is able to open the arm 5 smoothly.

[0102] Also, the uppermost point A of the gradient line GL rises higher as the amount in which the left operating lever 26L is operated increases, as shown in FIG. 6, so that the amount of discharge from the main pump 14 is not restricted excessively.

[0103] To be more specific, by re-positioning the uppermost point A as described above, the energy-saving control part 30B can prevent the amount of discharge Q from being smaller when an arm-opening operation is performed in a full-lever operation.

[0104] For example, assuming that the left operating lever 26L is operated in an arm-opening direction in a full-lever operation, if the gradient line GL is fixed to the gradient line GL1 that is used when the lever is operated slightly, the upper limit of the command value Qn is limited to the setting value Qmax1, which is smaller than the setting value Qmax3. That is, despite the situation in which a full-lever operation is performed and the amount of discharge Q therefore needs to be maximized, the main pump 14 still cannot increase its swashplate tilting angle sufficiently.

[0105] On the other hand, when the gradient line GL3 is used as the gradient line GL, the uppermost point A3 is set as the uppermost point A. In this case, the energy-saving control part 30B derives the setting value Qmax3 as the command value Qn if the actual control pressure Pn is the first set pressure Px. As a result of this, the main pump 14 is controlled to exhibit the maximum swashplate tilting angle, so that hydraulic oil can be discharged in the maximum amount of discharge.

[0106] The same is true when the arm 5 is slowed down or stopped during an arm-opening operation. For example, when the left operating lever 26L returns from a full-lever operation to a slight operation, the amount of hydraulic oil that passes through the aperture 18 increases. This is because most of the hydraulic oil discharged from the main pump 14 is exhausted to a hydraulic oil tank T1 through the center bypass pipeline CB.

[0107] When the hydraulic oil to pass through the aperture 18 increases, the control pressure Pn (negative control pressure) also increases; consequently, the command value Qn drops as shown in FIG. 6. If the gradient line GL is fixed to the gradient line GL3, the command value Qn drops at a greater rate than when the gradient line GL is fixed to the gradient line GL1, and drops to the minimum command value Qmin. Because the gradient line GL3 shows such a relatively large inclination (rate of decrease), the rate of decrease in the amount of discharge from the main pump 14 relative to the decrease in the amount of the left operating lever 26L's operation is also excessively large. The operator therefore may not be able to perform a stable arm-opening operation. This is because the excavator 100 shakes back and forth as when an arm-opening operation is started.

[0108] On the other hand, when the gradient line GL1 is used as the gradient line GL that corresponds to the amount of the left operating lever 26L's operation (slight operation) shortly before the arm 5 stops, the upper limit of the command value Qn is limited to the setting value Qmax1, which is smaller than the setting value Qmax3. Therefore, the rate of decrease in the amount of discharge from the main pumps 14 relative to the decrease in the amount of the left operating lever 26L's operation can be kept low compared to when the gradient line GL3 is used as the gradient line GL. As a result of this, the shake of the excavator 100 in the front-rear direction when slowing down the arm 5 is mitigated, thus allowing the operator to slow down the arm 5 smoothly.

[0109] Also, the uppermost point A of the gradient line GL drops lower as the amount of the left operating lever 26L's operation decreases, as shown in FIG. 6. Therefore, the amount of the left operating lever 26L's operation is reduced gradually, and the amount of discharge from the main pumps 14 does not change suddenly.

[0110] That is, the energy-saving control part 30B can prevent the amount of discharge Q from being unstable when an arm-opening operation is slowed down by re-positioning the uppermost point A as described above.

[0111] In this way, the controller 30 can control the amount of discharge Q of the main pump 14 more flexibly by changing the characteristics of flow rate control in negative control depending on the way the left operating lever 26L is operated, that is, by re-positioning the uppermost point A in the vertical-axis direction. To be more specific, the energy-saving control part 30B can prevent or substantially prevent the amount of hydraulic oil that flows into the arm cylinder 8 from being unstable by adjusting the gradient line GL based on the amount of the left operating lever 26L's operation. Therefore, the energy-saving control part 30B can smoothly open the arm 5 in response to an operation of the left operating lever 26L in an arm-opening direction, for example.

[0112] Although the above description with reference to FIG. 6 has illustrated a case in which the left operating lever 26L is operated in an arm-opening direction, the above description applies likewise when the left operating lever 26L is operated in an arm-folding direction, when the left operating lever 26L is operated in the left-right direction, when the right operating lever 26R is operated in the front-rear direction, when the right operating lever 26R is operated in the left-right direction, when the drive lever 26D is operated in the front-rear direction, and when the drive pedal is operated in the front-rear direction.

[0113] Next, the process in which the controller 30 limits the movement of driven elements (hereinafter referred to as the "movement limiting process") will be described with reference to FIG. 7. FIG. 7 is a flowchart of an example of the movement limiting process. The controller 30 repeats this movement limiting process in a predetermined control cycle.

[0114] First, the controller 30 determines whether or not an operating device 26 has been operated (step ST1). According to the present embodiment, the controller 30 determines whether or not an operating device 26 has been operated based on outputs of operation sensors 29. For example, the controller 30 determines whether or not an arm-folding operation has been performed, as well as whether or not an arm-opening operation has been performed, based on an output of the operation sensor 29LA. The controller 30 also determines whether or not a left rotating operation has been performed and whether or not a right rotating operation has been performed, based on an output of the operation sensor 29LB. In addition, the controller 30 determines whether or not a boom-raising operation has been performed and whether or not a boom-lowering operation has been performed, based on an output of the operation sensor 29RA, and determines whether or not a bucket-folding operation has been performed and whether or not a bucket-opening operation has been performed, based on an output of the operation sensor 29RB. Similarly, the controller 30 determines whether or not the left crawler 1CL has been operated to move forward and whether or not the left crawler 1CL has been operated to move backward, based on an output of the operation sensor 29DL. The controller 30 also determines, based on an output of the operation sensor 29DR, whether or not the right crawler 1CR has been operated to move forward and whether or not the right crawler 1CR has been operated to move backward.

[0115] If it is determined that no operating device 26 has been operated ("NO" in step ST1), the controller 30 ends the current movement limiting process.

[0116] If it is determined that an operating device 26 has been operated ("YES" in step ST1), the controller 30 determines whether the operation has been performed as part of a job at a predetermined work site (step ST2), that is, whether or not the excavator 100 is at a predetermined work site, based on images obtained by image-capturing devices that serve as object detection devices 70. For example, when the controller 30 detects an image of a road cone, a cone bar, a type A barricade, a single-tube barricade, a guard rail, or the like, in images obtained by the image-capturing devices, the controller 30 determines that a job is taking place at the predetermined site. Note that the controller 30 may determine whether or not the excavator 100 is at a predetermined work site based on an output of the positioning device 85. For example, the controller 30 may determine that a job is taking place at a predetermined site when the excavator 100 is currently located in a geographical range that is set in advance as the range of the predetermined work site. In this case, the geographical range may be defined by multiple pieces of location-related information (for example, latitude, longitude, altitude, etc.).

[0117] "A predetermined work site" as used herein may refer to, for example, a work site located in an urban area, a work site located adjacent to a roadway, a sidewalk, a cliff, a hole, and so forth. Alternatively, a predetermined work site may refer to a work site where a predetermined job, such as deep excavation or craning, takes place. Assuming that there is an object near the excavator 100, the predetermined work site in this case may refer to a work site in which the excavator 100 performs a job, and which is smaller than the round area with the maximum working radius (that is, the area represented by a circle about the axis of rotation, where the distance between the axis of rotation and the position where the attachment AT reaches when the attachment AT is fully extended, and serving as the radius of the circle). If an image of a hole that is deeper than a predetermined depth is detected in an image captured by an image-capturing device, the controller 30 may determine that a job (deep excavation) by the excavator 100 is taking place at the work site. When an image of cargo lifted by an attachment AT is detected in an image captured by an image-capturing device, the controller 30 may determine that a predetermined job (craning) is taking place at the work site.

[0118] If it is determined that the operation performed on the operating device 26 is not related to the job taking place at the predetermined work site ("NO" in step ST2), the controller 30 ends this movement limiting process.

[0119] If it is determined that the operation performed on the operating device 26 is related to the job taking place at the predetermined work site ("YES" in step ST2), the controller 30 limits the movement of driven elements (step ST3). According to the present embodiment, the controller 30 limits the movement of driven elements by controlling the amount of discharge of the main pumps 14. The driven elements include at least one of the lower traveling body 1, the upper rotating body 3, the boom 4, the arm 5, and the bucket 6.

[0120] Structured and configured as described above, the controller 30 can limit the movement of driven elements when the excavator 100 is located at a predetermined work site. For example, the controller 30 can slow down the moving speed of the attachment AT when it starts moving. As a result of this, for example, the controller 30 can prevent, more reliably, the attachment AT and objects around the attachment AT from coming into contact with each other.

[0121] Next, another example of the contents of the reference table that the energy-saving control part 30B looks up will be described with reference to FIG. 8. FIG. 8 shows another example of the relationship (flow-rate control characteristics) between the control pressure Pn and the command value Qn, which is another example of the contents of the reference table, and which corresponds to FIG. 6. FIG. 8 shows the characteristics of flow-rate control applied when limiting the movement of driven elements. FIG. 6 shows the characteristics of flow-rate control applied when the movement of driven elements is not limited. The reference table shown in FIG. 8 is used when controlling the amount of discharge of the left main pump 14L and the amount of discharge of the right main pump 14R. Assuming that the amount of discharge of the left main pump 14L is subject to control, the horizontal axis in FIG. 8 is the control pressure detected by the left control pressure sensor 19L, and the vertical axis in FIG. 8 is the command value for the amount of discharge of the left main pump 14L. Similarly, when the amount of discharge of the right main pump 14R is subject to control, the horizontal axis in FIG. 8 is the control pressure detected by the right control pressure sensor 19R, and the vertical axis in FIG. 8 is the command value for the amount of discharge of the right main pump 14R.

[0122] FIG. 8 is a diagram showing the contents of the reference table to be looked up when the left operating lever 26L is operated in an arm-opening direction. In FIG. 8, the solid line including a gradient line GL1A represents the flow-rate-control characteristics applied when the left operating lever 26L is operated slightly. Also, in FIG. 8, the dashed line including a gradient line GL2A represents the flow-rate-control characteristics applied when the left operating lever 26L is operated in a half-lever operation. Furthermore, in FIG. 8, the dashed-and-dotted line including a gradient line GL3A represents the flow-rate-control characteristics applied when the left operating lever 26L is operated in a full-lever operation.

[0123] The gradient line GL1A and the gradient line GL1 of FIG. 6 share in common the same tendency of the command value Qn increasing as the control pressure Pn decreases. However, the gradient line GL1A is different from the gradient line GL1 of FIG. 6 in that the rate of increase escalates as the control pressure Pn decreases. The gradient line GL1 of FIG. 6 shows a constant rate of increase. Also, the gradient line GL2A and the gradient line GL2 of FIG. 6 share in common the same tendency of the command value Qn increasing as the control pressure Pn decreases. However, the gradient line GL2A is different from the gradient line GL2 of FIG. 6 in that the rate of increase escalates as the control pressure Pn decreases. Also, the gradient line GL3A and the gradient line GL3 of FIG. 6 share in common the same tendency of the command value Qn increasing as the control pressure Pn decreases. However, the gradient line GL3A is different from the gradient line GL3 of FIG. 6 in that the rate of increase escalates as the control pressure Pn decreases.

[0124] The controller 30 can limit the movement of driven elements as appropriate by applying, for example, the flow-rate control characteristics shown in FIG. 8. For example, when the excavator 100 is located at a predetermined work site and its arm 5 starts moving in an arm-opening operation, the controller 30 can slow down the speed at which the arm 5 opens. That is, the controller 30 can prevent or substantially prevent the arm 5 from opening at an excessively fast speed during an arm-opening operation. Note that, in the example illustrated in FIG. 8, the controller 30 does not limit the maximum value of the arm 5's moving speed even when the movement of driven elements including the arm 5 is limited. In other words, the controller 30 is configured such that the maximum value of the arm 5's moving speed when the movement of the arm 5 is limited and the maximum value of the arm 5's moving speed when the movement of the arm 5 is not limited are the same. This means that the moving speed of the arm 5 reaches the maximum value regardless of whether or not the movement of the arm 5 is limited, insofar as an arm-opening operation in a full-lever operation continues. However, if the movement of the arm 5 is limited, the time required for the arm 5's moving speed to reach its maximum value is longer than when the movement of the arm 5 is not limited.

[0125] Next, with reference to FIG. 9, an example situation in which the movement of a driven element is limited based on the movement limiting process will be described. FIG. 9 is a perspective view of the excavator 100 engaged in craning.

[0126] In the example illustrated in FIG. 9, the excavator 100 is lifting up a sewer pipe BP in order to bury it in an excavated ditch EX formed in a road. The operator of the excavator 100 is about to perform a right rotating operation based on an order from a rigger FS, who is present at the left front of the excavator 100. The controller 30 keeps monitoring the distance DB between the excavator 100 (bucket 6) or the sewer pipe BP and the rigger FS, based on outputs of a front camera 70F. The operator of the excavator 100 is using the left operating lever 26L to rotate the upper rotating body 3 to the right so as to bring the sewer pipe BP closer to the excavated ditch EX. In doing so, however, the rigger FS might get too close to the excavator 100 (bucket 6) or the sewer pipe BP, for example, to adjust the orientation of the sewer pipe BP.

[0127] In this situation, the controller 30 may determine that a job is taking place at a predetermined site if an image of, for example, at least one of a road cone RC, a guard rail GR, a utility pole EP, and an object such as a sewer pipe BP, is detected in an image captured by the front camera 70F, and thereupon hold the movement of the driven element.

[0128] To be more specific, when an image of a guard rail GR or a utility pole EP is detected in an image captured by the front camera 70F, the controller 30 may determine that a job is taking place at a predetermined site (a site that is adjacent to a sidewalk or a roadway), and thereupon hold the movement of the driven element.

[0129] Alternatively, if an image of hooked cargo (such as a sewer pipe BP lifted up by a hook at the tip of the arm 5) is detected in an image captured by the front camera 70F, the controller 30 may determine that a job is taking place at a predetermined site (a site that is adjacent to a sidewalk or a roadway), and thereupon hold the movement of the driven element.

[0130] Thus preventing or substantially preventing movement of a driven element may be implemented by preventing or substantially preventing the main pumps 14 from accelerating, that is, by switching, for example, the flow rate control characteristics shown in FIG. 6 to those illustrated in FIG. 8. Alternatively, preventing or substantially preventing movement of a driven element may be implemented by reducing the maximum operating speed of the driven element, reducing the relief pressure of a relief valve (not shown) provided in the center bypass pipeline CB, reducing the output power (the number of rotations per unit time) of the drive source such as the engine 11 or an electric motor, switching the operation mode of the excavator 100, and so forth. Applicable operation modes include, for example, an excavation mode that is selected when excavation is performed, a crane mode that is selected when craning is performed, and so forth. In the crane mode, the amount of actuator operation in response to the amount of operation on the operating devices 26 is smaller than in the excavation mode.

[0131] Note that, when a left rotating operation is performed while the distance DB is less than a predetermined value, the controller 30 may output a block command to the control valve 60 and switch the pilot line CD1 to a disconnected state. This is because the left operating lever 26L is placed in a deactivated state and the rotation of the rotating hydraulic motor 2A stops.

[0132] If the excavator 100's movement is restricted completely while there are objects around the excavator 100, not only a left rotating operation, but a right rotating operation will also be disabled. Thus, every time an operation is made on an operating device 26, the controller 30 may determine whether or not it is permitted to move the driven element. In the situation illustrated in FIG. 9, the controller 30 prohibits the rotating hydraulic motor 2A from rotating in response to a left rotating operation by the operator. On the other hand, the rotating hydraulic motor 2A is permitted to rotate in response to a right rotating operation by the operator. This is because, even if the excavator 100 is rotates to the right, there is no risk of bringing the excavator 100 and an object too close to each other. As a result of this, it is possible to prevent the excavator 100 (bucket 6) or the sewer pipe BP from getting too close to the rigger FS, and quickly bring the sewer pipe BP close to the excavated ditch EX.

[0133] Alternatively, the controller 30 may be configured not to limit the movement of a driven element until the distance DB between the excavator 100 (bucket 6) or the sewer pipe BP and the rigger FS is less than a predetermined value, even if the excavator 100 is located at a predetermined work site. That is, the controller 30 may be configured to limit the movement of a driven element only if the driven element starts moving while the distance DB is less than a predetermined value.

[0134] Also, the controller 30 may be configured to send a notice to the operator of the excavator 100 and / or the rigger FS when the distance DB falls below a predetermined value. In the example illustrated, when the controller 30 determines that the distance DB is less than a predetermined value based on an image captured by the front camera 70F, alarm sounds may be output from both the exterior alarm 45A and the interior alarm 45B. This is to draw the attention of the operator and the rigger FS. Note that the controller 30 may be configured such that image information that indicates that the distance DB has fallen below a predetermined value is displayed on the display device 40 and thus draws the attention of the operator, or a rotating light attached to the outside of the cabin 10 is lit and thus draws the attention of the rigger FS.

[0135] Structured and configured as described above, the controller 30 can prevent, more reliably, the attachment AT and an object around the attachment AT from coming into contact with each other when the excavator 100 is located at a work site where craning is performed.

[0136] Next, another example situation in which the movement of a driven element is limited based on the movement limiting process will be described with reference to FIG. 10. FIG. 10 is a side view of the excavator 100 engaged in deep excavation.

[0137] In the example illustrated in FIG. 10, the excavator 100 positions the bucket 6 deeper in the hole HL in order to dig the hole HL deeper. In the hole HL, the worker WK is waiting near the bucket 6 to check the progress of the job. The worker WK sends signals to the operator of the excavator 100 on an as-needed basis. Upon receiving a signal from the worker WK, the operator of the excavator 100 loads earth and sand from the bottom of the hole HL into the bucket 6, and then loads the earth and sand loaded in the bucket 6, onto the loading bed of a dump truck DT parked near the excavator 100. The controller 30 keeps monitoring whether or not the worker WK is present near the bucket 6, based on outputs of the attachment camera 70A. In the example illustrated, the controller 30 includes a linking pin 6P that links the arm 5 and the bucket 6. The controller 30 monitors whether the worker WK is present within a range of a predetermined distance DS (the range represented by the dashed line L1) from the linking pin 6P. Note that dashed-and-dotted line L2 in FIG. 10 represents the photographing range of the attachment camera 70A.

[0138] The operator of the excavator 100 is attempting to carry out a complex operation that combines together an arm-folding operation and a bucket-folding operation by using the operating devices 26 to collect the earth and sand in the hole HL into the bucket 6. When this takes place, the worker WK might get too close to the bucket 6 in order to check the position (depth) of the teeth of the bucket 6.

[0139] In such a situation, if the controller 30 detects the worker WK within a predetermined distance DS from the linking pin 6P based on an image captured by the attachment camera 70A, the controller 30 may determine that a job is taking place at a predetermined work site (a work site where deep excavation takes place) and limit the movement of the driven element. That is, the controller 30 may determine that the worker WK is near the bucket 6 and limit the movement of the driven element.

[0140] In the illustrated example, the controller 30 switches the flow-rate control characteristics shown in FIG. 6 to the flow-rate control characteristics shown in FIG. 8. This makes it possible to reduce the rate of increase in the moving speed of the attachment AT when the attachment AT starts moving, compared to when the movement of driven elements is not limited. That is, the controller 30 can reduce the rate at which the amount of discharge of the main pumps 14 increases in response to an increase in the amount of operation on the operating devices 26, compared to when the movement of driven elements is not limited. Note that even when limiting the movement of driven elements in this manner, the controller 30 does not limit the maximum moving speed of the attachment AT (the maximum command value Qmax corresponding to the maximum amount of discharge of the main pumps 14).

[0141] To be more specific, for example, when the operator starts a boom-lowering operation to move the bucket 6, located midair above the hole HL, into the hole HL, the controller 30 can slow down the downward movement of the boom 4. That is, compared to the case in which the controller 30 does not limit the movement of a driven element (boom 4), the controller 30 reduces the rate at which the flow rate of hydraulic oil into a rod-side oil chamber of the boom cylinder 7 increases following the increase in the amount of the right operating lever 26R's operation, until the amount of the right operating lever 26R's operation in a boom-lowering direction reaches a predetermined amount of operation, thus limiting the speed at which the boom 4 lowers.

[0142] Also, the controller 30 can slow down the folding operation of the arm 5, for example, when the operator starts an arm-folding operation to excavate earth and sand at the bottom of the hole HL with the bucket 6 having reached the bottom of the hole HL. Similarly, the controller 30 can slow down the raising operation of the boom 4 when, for example, the operator starts a boom-raising operation to lift the earth and sand caught in the bucket 6.

[0143] If the operator starts a complex operation that combines together a rotating operation and a boom-raising operation so as to raise the boom 4 while also rotating the upper rotating body 3, the bucket 6 being lifted midair above the hole HL, the controller 30 does not slow down the boom-raising rotating operation (the complex operation combining a rotating operation and a boom-raising operation together). This is because the controller 30 can determine that the worker WK is not present within the range of the predetermined distance DS from the linking pin 6P if the bucket 6 is lifted midair above the hole HL. This allows the operator to perform an unrestricted boom-raising rotating operation and load earth and sand onto the loading bed of the dump truck DT quickly and stress-free. Also, when the operator starts a complex operation that combines a rotating operation and a boom-lowering operation together to move the bucket 6 from above the loading bed of the dump truck DT to above the hole HL, the controller 30 does not slow down the boom-lowering rotating operation (the complex operation combining a rotating operation and a boom-lowering operation together). The target of detection by the controller 30 does not necessarily have to be the worker WK. For example, the controller 30 may determine whether or not the operation of actuators needs to be restricted based on whether or not a pre-registered object other than earth and sand, such as a guard rail GR, a utility pole EP, or a sewer pipe BP, is detected. Furthermore, the controller 30 may determine whether or not the operation of actuators needs to be restricted based on the angle (slope) of the side walls of the hole HL in FIG. 10, based on whether or not there is a safety device (such as a trench box, for example), based on whether or not the excavator shakes when it moves, and so forth. In this way, the controller 30 can improve the safety of the work site by determining whether or not the operation of actuators needs to be restricted based on factors such as the presence or absence of an object in the work area.

[0144] Note that preventing or substantially preventing movement of a driven element may be implemented by reducing the maximum operating speed of the driven element, reducing the relief pressure of a relief valve (not shown) provided in the center bypass pipeline CB, reducing the output power (the number of rotations per unit time) of a drive source such as the engine 11 or an electric motor, switching the operation mode of the excavator 100, and so forth.

[0145] Structured and configured as described above, the controller 30 can prevent, more reliably, an attachment AT and objects around the attachment AT from coming into contact with each other, even when the excavator 100 is located at a work site where deep excavation takes place.

[0146] Next, an operating state screen, which is a screen displayed on the display device 40 while the excavator 100 is operating, will be described with reference to FIG. 11 and FIG. 12. FIG. 11 and FIG. 12 show example structures of the operating state screen.

[0147] The display device 40 includes a control part 40a, an image display part 41, and an operating part 42. The control part 40a controls the images displayed on the image display part 41. According to the present embodiment, the control part 40a is formed with a computer equipped with a CPU, a volatile memory device, a non-volatile memory device, and so forth. In this case, the control part 40a reads programs that support each function from the non-volatile memory device, loads them in the volatile memory device, and causes the CPU to execute corresponding processes.

[0148] The image display part 41 includes a date / time display area 41a, a drive mode display area 41b, an end attachment display area 41c, a mileage display area 41d, an engine control state display area 41e, an engine running time display area 41f, a cooling water temperature display area 41g, a remaining fuel amount display area 41h, a rotation speed mode display area 41i, a remaining urea amount display area 41j, a hydraulic oil temperature display area 41k, an air-conditioner operating state display area 41m, an image display area 41n, and a menu display area 41p.

[0149] The drive mode display area 41b, end attachment display area 41c, engine control state display area 41e, rotation speed mode display area 41i, and air-conditioner operating state display area 41m are areas where display setting state information is displayed, which is information related to the settings of the excavator 100. The mileage display area 41d, engine running time display area 41f, cooling water temperature display area 41g, remaining fuel amount display area 41h, remaining urea amount display area 41j, and hydraulic oil temperature display area 41k are areas where operating state information is displayed, which is information related to the operating state of the excavator 100.

[0150] The date / time display area 41a is an area where the current date and time is displayed. The drive mode display area 41b is an area where the current drive mode is displayed. The end attachment display area 41c is an area where an image representing the currently attached end attachment is displayed. The mileage display area 41d is an area where mileage information calculated by the controller 30 is displayed. The mileage display area 41d includes an average mileage display area 41d1 where the average mileage over the whole period or the average mileage in a part of the period is displayed, and a momentary mileage display area 41d2. "The whole period" means, for example, the entire period after the excavator 100 is shipped. "A part of the period" may be, for example, any period set as desired by the operator.

[0151] The engine control state display area 41e is an area where the control state of the engine 11 is displayed. The engine running time display area 41f is an area where information about the time that the engine 11 runs is displayed. The cooling water temperature display area 41g is an area where the current temperature of the engine cooling water is displayed. The remaining fuel amount display area 41h is an area where the remaining amount of fuel stored in the fuel tank is displayed. The rotation speed mode display area 41i is an area where the current rotation speed mode set by the engine rotation speed adjusting dial 75 is displayed in an image. The remaining urea amount display area 41j is an area where the remaining amount of urea stored in a urea tank is displayed in an image. The hydraulic oil temperature display area 41k is an area where the temperature of the hydraulic oil in the hydraulic oil tank is displayed.

[0152] The air-conditioner operating state display area 41m includes: a vent display area 41m1 that displays the current position of the vent; an operation mode display area 41m2 that displays the current operation mode; a temperature display area 41m3 that displays the current temperature setting; and an airflow display area 41m4 that displays the current airflow setting.

[0153] The image display area 41n is an area where images captured by image-capturing devices are displayed. The image display area 41n includes a first image display area 41n1 located in an upper part and a second image display area 41n2 located in a lower part. In the examples shown in FIG. 11 and FIG. 12, an image of the bucket and its surroundings, or a "bucket-encompassing image BG," is shown in the first image display area 41n1, and a bird's-eye view FV is shown in the second image display area 41n2. However, in the image display area 41n, the bucket-encompassing image BG may be positioned in the second image display area 41n2 and the bird's-eye view FV may be positioned in the first image display area 41n1. Also, in the examples shown in FIG. 11 and FIG. 12, the bucket-encompassing image BG and the bird's-eye view FV are positioned next to each other vertically, but they may be positioned with an interval between them.

[0154] The bucket-encompassing image BG is an image that is displayed when deep excavation is performed, and is an image that is generated based on images captured by the attachment camera 70A. The bucket-encompassing image BG may be an image that has been subjected to a point-of-view change process, or may be an image that has not been subjected to a point-of-view change process. Also, the bucket-encompassing image BG may be a CG image including an arm image 5G (a CG image showing the position of the arm 5), a bucket image 6G (a CG image showing the position of the bucket 6), and a worker image WG (a CG image showing the position of a worker WK working near the bucket 6).

[0155] In the examples illustrated, the bucket-encompassing image BG may include a first bucket-encompassing image BG1 (see FIG. 11) and a second bucket-encompassing image BG2 (see FIG. 12). The first bucket-encompassing image BG1 is an image that shows the state inside the hole HL, which is the target of deep excavation, viewed from above. The second bucket-encompassing image BG2 is an image that shows positions in the hole HL, which is the target of deep excavation, viewed from the side.

[0156] The first bucket-encompassing image BG1 includes an arm image 5G, a bucket image 6G, and a worker image WG, as shown in FIG. 11. The arm image 5G shows the position of the arm 5 viewed from above; the bucket image 6G shows the position of the bucket 6 when viewing the hole HL from above; and the worker image WG shows the position of the worker WK when viewing the hole HL from above. By looking at the first bucket-encompassing image BG1, the operator of the excavator 100 can recognize that a worker WK is in the hole HL, diagonally to the left and in front of the bucket 6.

[0157] The second bucket-encompassing image BG2 includes an excavator image 100G, a hole image HG, and a worker image WG, as shown in FIG. 12. The excavator image 100G is a CG image showing the position of the excavator 100 viewed from the side, and includes an arm image 5G and a bucket image 6G. The hole image HG is a CG image showing the position of the hole HL, which is the target of deep excavation. Referring to FIG. 12, the arm image 5G shows the position of the arm 5 when viewing the work site from the side. The bucket image 6G shows the position of the bucket 6 when viewing the work site from the side. The worker image WG shows the position of the worker WK when viewing the work site from the side, and the hole image HG shows the position of the hole HL when viewing the work site from the side. By looking at the second bucket-encompassing image BG2, the operator of the excavator 100 can recognize that a worker WK is present in front of the bucket 6, at approximately the same height as the bucket 6.

[0158] The bird's-eye view FV is an image seen from a virtual point of view and generated by the control part 40a. The bird's-eye view FV is generated based on respective images obtained by the rear camera 70B, the left camera 70L, and the right camera 70R. Also, an excavator shape GE, which corresponds to the excavator 100, is positioned in the center of the bird's-eye view FV. This is to allow the operator to intuitively understand the positional relationship between the excavator 100 and objects around the excavator 100.

[0159] In the examples shown in FIG. 11 and FIG. 12, the image display area 41n is vertically long, but it may be horizontally long as well. In the event the image display area 41n is horizontally long, the image display area 41n may show the bird's-eye view FV in the first image display area 41n1 on the left and show the bucket-encompassing image BG in the second image display area 41n2 on the right. In this case, the bird's-eye view FV may be positioned to the left of, and spaced apart from, the bucket-encompassing image BG. Alternatively, the bird's-eye view FV may be positioned to the right of the bucket-encompassing image BG.

[0160] The menu display area 41p includes tab areas 41p1 to 41p7. In the examples shown in FIG. 11 and FIG. 12, the tab areas 41p1 to 41p7 are positioned at intervals from each other on the left and right, near the lowermost part of the image display part 41. The tab areas 41p1 to 41p7 each show an icon representing the content of related information.

[0161] In the tab area 41p1, menu item icons, which represent individual items on the menu, are displayed. When the operator makes a selection in the tab area 41p1, the icons displayed in the tab areas 41p2 to 41p7 switch to icons associated with the selected item in the menu.

[0162] In the tab area 41p4, an icon representing information about a digital level is displayed. When the operator selects the table area 41p4, the bucket-encompassing image BG switches to a first screen that shows information about the digital level.

[0163] The tab area 41p6 displays an icon representing information related to ICT (Information and Communication Technology)-based construction technology. When the operator selects the tab area 41p6, the bucket-encompassing image BG switches to a second screen that shows information about ICT-based construction.

[0164] In the tab area 41p7, an icon representing information about the crane mode is displayed. When the operator selects the tab area 41p7, the bucket-encompassing image BG switches to a third screen that shows information about the crane mode.

[0165] However, any of these menu screens, including the first screen, second screen, and third screen, may be displayed to overlap the bucket-encompassing image BG. For example, the bucket-encompassing image BG may be reduced in size to make room for the menu screen. Alternatively, the bird's-eye view FV may be configured to switch to the menu screen. The menu screen may be displayed to overlap the bird's-eye view FV. Alternatively, the bird's-eye view FV may be reduced in size to make room for displaying the menu screen.

[0166] In the examples illustrated in FIG. 11 and FIG. 12, no icons are displayed in the tab areas 41p2, 41p3, and 41p5. Therefore, even if the operator performs operations on the tab areas 41p2, 41p3, and 41p5, the images displayed on the image display part 41 do not change.

[0167] Note that the icons to be displayed in the tab areas 41p1 to 41p7 are by no means limited to those given in the above examples, and icons representing other information may be displayed as well.

[0168] In the examples shown in FIG. 11 and FIG. 12, the operating part is composed of multiple push-button switches that allow the operator to select the tab areas 41p1 to 41p7, enter the settings, and so forth. To be more specific, the operating part 42 includes seven switches 42a1 to 42a7 positioned in the upper row and seven switches 42b1 to 42b7 positioned in the lower row. The switches 42b1 to 42b7 are positioned below the switches 42a1 to 42a7, respectively. However, the above example by no means limits the number, types, and positioning of switches in the operating part 42. For example, the operating part 42 may be formed such that the functions of multiple push-button switches are combined into one, like a jog wheel or a jog switch. Alternatively, the operating part 42 may be configured as a member that is separate from the display device 40. Also, the tab areas 41p1 to 41p7 may be configured as software buttons. In this case, the operator can select any tab area by touching and operating the tab areas 41p1 to 41p7.

[0169] In the examples illustrated in FIG. 11 and FIG. 12, the switch 42a1 is associated with the tab area 41p1 and positioned below the tab area 41p1, thus functioning as a switch for selecting the tab area 41p1. The same applies to each of the switches 42a2 to 42a7.

[0170] By means of this structure and configuration, the operator can intuitively understand which of the switches 42a1 to 42a7 he / she should operate when selecting a desired one among the tab areas 41p1 to 41p7.

[0171] The switch 42b1 is a switch for changing the photographed image displayed in the image display area 41n. The display device 40 is configured such that the photographed image displayed in the first image display area 41n1 of the image display area 41n is switched every time the switch 42b1 is operated, for example, in the order of the rear image, the left-side image, the right-side image, the bird's-eye view FV, and the bucket-encompassing image BG. Alternatively, the display device 40 may be configured such that the photographed image displayed in the second image display area 41n2 of the image display area 41n is changed every time the switch 42b1 is operated, for example, in the order of the rear image, the left-side image, the right-side image, the bird's-eye view FV, and the bucket-encompassing image BG. Alternatively, the display device 40 may be configured such that the photographed image displayed in the first image display area 41n1 of the image display area 41n and the photographed image displayed in the second image display area 41n2 of the image display area 41n are switched every time the switch 42b1 is operated.

[0172] In this way, the operator may switch the screen to be displayed in the first image display area 41n1 or in the second image display area 41n2 by operating the switch 42b1 as the operating part 42. Alternatively, the operator may switch the screens displayed in the first image display area 41n1 and in the second image display area 41n2 by operating the switch 42b1. The display device 40 may be provided with an additional switch for switching the screen displayed in the second image display area 41n2.

[0173] The switches 42b2 and 42b3 are switches for adjusting the airflow of the air conditioner. In the examples illustrated in FIG. 11 and FIG. 12, the operating part 42 is configured such that the airflow of the air conditioner is reduced when the switch 42b2 is operated or the airflow of the air conditioner is increased when the switch 42b3 is operated.

[0174] The switch 42b4 is a switch that switches on and off a heating and cooling function. In the examples illustrated in FIG. 11 and FIG. 12, the operating part 42 is configured such that the heating and cooling function is switched on and off every time the switch 42b4 is operated.

[0175] The switches 42b5 and 42b6 are switches for adjusting the temperature settings of the air conditioner. In the examples illustrated in FIG. 11 and FIG. 12, the operating part 42 is configured such that the temperature is set lower when the switch 42b5 is operated or set higher when the switch 42b6 is operated

[0176] The switch 42b7 is a switch for changing the content of the information which relates to the time that the engine 11 runs, and which is displayed in the engine running time display area 41f. The information about the time that the engine 11 runs includes, for example, the cumulative running time of the engine 11 in the whole period, the cumulative running time of the engine 11 in a part of the period, and so forth.

[0177] Also, the switches 42a2 to 42a6 and the switches 42b2 to 42b6 are configured such that the numbers displayed on or near the respective switches can be entered. Furthermore, the switches 42a3, 42a4, 42a5, and 42b4 are configured such that, when a cursor is displayed in the image display part 41, the cursor can be moved to the left and right, and up and down.

[0178] Note that the above-described functions imparted to the switches 42a1 to 42a7 and 42b1 to 42b7 are only examples. The switches 42a1 to 42a7 and the switches 42b1 to 42b7 may be configured to perform other or different functions as well.

[0179] As described above and shown in FIG. 1, the excavator 100 according to an embodiment of the present disclosure includes: a lower traveling body 1; an upper rotating body 3 mounted on the lower traveling body 1; an attachment AT mounted on upper rotating body 3 and including an end attachment such as a bucket 6; a controller 30 mounted on the upper rotating body 3 and serving as a control device; and actuators such as a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9 that move the attachment AT. The controller 30 is configured to control the movement of the actuators at a predetermined work site. To be more specific, the controller 30 is configured to facilitate and / or prevent or substantially prevent the actuators' movement. Facilitating the movement of the actuators may be implemented by, for example, facilitating the rise of the main pump 14, that is, by switching the characteristics of flow-rate control illustrated in FIG. 8 to those illustrated in FIG. 6. Alternatively, facilitating the movement of the actuators may be implemented by increasing the maximum operating speed of the actuators, increasing the relief pressure of a relief valve (not shown) provided in the center bypass pipeline CB, increasing the output power (the number of rotations per unit time) of a drive source such as the engine 11 or an electric motor, switching the operation mode of the excavator 100, and so forth. Preventing or substantially preventing movement of the actuator means, for example, preventing or substantially preventing the main pumps 14 from accelerating, that is, by changing the characteristics of flow-rate control illustrated in FIG. 6 to those illustrated in FIG. 8. Alternatively, preventing or substantially preventing movement of the actuators may be implemented by stopping the actuators, reducing the maximum operating speed of the actuators, reducing the relief pressure (not shown) of a relief valve provided in the center bypass pipeline CB, reducing the output power (the number of rotations per unit time) of a drive source such as the engine 11 or an electric motor, switching the operation mode of the excavator 100, and so forth.

[0180] Structured and configured as described above, the controller 30 can prevent, more reliably, the excavator's attachment and objects around the attachment from coming into contact with each other. This is because, when the excavator 100 is located at a specific work site where a situation is likely to arise in which a worker has to work near the attachment, such as a work site in an urban area, the controller 30 can prevent or substantially prevent the actuators' movement. On the other hand, when the excavator 100 is located at a work site other than a specific work site where a situation is likely to arise in which the worker is forced to work near the attachment, the controller 30 can facilitate the movement of the actuators. Therefore, when the excavator 100 is located at a work site other than a specific work site such as the one described above, the controller 30 can improve the work efficiency of the excavator 100.

[0181] Note that the controller 30 may be configured such that whether the excavator 100 is at a predetermined work site is determined based on information obtained by information obtaining devices, and, when the excavator 100 is determined to be at a predetermined work site, the movement of the actuators is facilitated, prevented, or substantially prevented. Examples of the information obtaining devices include a positioning device 85, image-capturing devices, and communication devices. The information obtaining devices may be switches (for example, switches provided on the display device 40) that the operator can operate to let the controller 30 know that the excavator 100 is at a predetermined work site.

[0182] To be more specific, the controller 30 may be configured such that whether or not the excavator 100 is at a predetermined work site is determined based on location information obtained by the positioning device 85 serving as an information obtaining device, and, when the excavator 100 is determined to be at a predetermined work site, the movement of the actuators is facilitated, prevented, or substantially prevented.

[0183] Alternatively, the controller 30 may be configured such that whether or not the excavator 100 is at a predetermined work site is determined based on images obtained by image-capturing devices serving as information obtaining devices, and, when the excavator 100 is determined to be at a predetermined work site, the movement of the actuator is facilitated, prevented, or substantially prevented.

[0184] Structured and configured as described above, the controller 30 can prevent a driven element's movement from being restricted excessively, and prevent, more reliably, the excavator's attachment and objects around the attachment from coming into contact with each other. This is because controller 30 can determine, more accurately, whether the excavator 100 is located at a predetermined work site where the movement of the driven element needs to be limited. That is, the controller 30 can prevent or substantially prevent the current work site from being misidentified as a predetermined work site.

[0185] Also, according to another embodiment of the present disclosure, as shown in FIG. 1, an excavator 100 includes: a lower traveling body 1; an upper rotating body 3 mounted on lower traveling body 1; an attachment AT mounted on upper rotating body 3 and including an end attachment such as a bucket 6; actuators such as a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9 that move the attachment AT; and a controller 30 that serves as a control device to detect objects around the end attachment. The controller 30 is configured to prevent or substantially prevent the actuators' movement when an object is detected around the end attachment.

[0186] Structured and configured as described above, the controller 30 can prevent, more reliably, the excavator's attachment and objects around the attachment from coming into contact with each other. Also, the controller 30 is configured to prevent or substantially prevent the actuators' movement when an object is detected around the end attachment, rather than holding the actuators' movement. Therefore, the operator of the excavator 100 can continue the job by the excavator 100 even when a worker is present around the end attachment. Thus, the above-described structure and configuration can prevent or substantially prevent a decrease in the work efficiency of the excavator 100 even when workers are present around the end attachment.

[0187] Note that the controller 30 may be configured to detect objects around the end attachment based on images obtained by image-capturing devices attached to the attachment AT.

[0188] In the example illustrated in FIG. 10, the controller 10 is configured to detect objects around the bucket 6 based on images captured by attachment cameras 70A, which are attached to the bucket cylinder 9. However, the controller 30 may also be configured to detect objects around the bucket 6 based on images captured by at least one of the rear camera 70B, the front camera 70F, the left camera 70L, and the right camera 70R installed in the upper rotating body 3. Alternatively, the controller 30 may be configured to detect objects around the bucket 6 based on images captured by outer cameras installed outside the excavator 100. To be more specific, the controller 30 may be configured to detect objects around the bucket 6 based on images captured by a camera 70D mounted on an aircraft 50, images captured by a fixed camera 70P attached to a pole 55 erected at the work site, and the like, as shown in FIG. 10. The aircraft 50 may be an autonomous aircraft that can be flown by remote control or automatic piloting, and may be, for example, a multicopter, an airship, or the like.

[0189] Structured and configured as described above, the controller 30 can prevent a driven element's movement from being restricted excessively, and prevent, more reliably, the excavator's attachment and objects around the attachment from coming into contact with each other. This is because the controller 30 can detect, more accurately, whether or not there is an object around the end attachment. That is, the controller 30 can prevent or substantially prevent objects from being misdetected.

[0190] Also, in the event the controller 30 detects that a worker is present around the end attachment, the controller 30 may alert at least one of the operator and the worker.

[0191] Structured and configured as described above, the controller 30 can prevent, more reliably, the excavator's attachment and a worker near the attachment from coming into contact with each other.

[0192] Note that the actuators are typically hydraulic actuators. The controller 30 may be configured to facilitate, prevent, or substantially prevent movement of the hydraulic actuators by controlling the movement of at least one of: hydraulic pumps such as the main pumps 14 that supply hydraulic oil to the hydraulic actuators; control valves such as the control valves 171 to 176 that control the flow rate of hydraulic oil that flows into the hydraulic actuators; and the drive source such as the engine 11 that drives the hydraulic pumps. However, the actuators may be electric actuators as well.

[0193] Also, information obtained by the excavator 100 may be shared with the administrator and other excavator's operators via an excavator control system SYS such as the one shown in FIG. 13. FIG. 13 is a schematic diagram showing an example structure of the excavator control system SYS. The control system SYS is a system for controlling the excavator 100. According to the present embodiment, the control system SYS is mainly composed of an excavator 100, an assisting device 200, and a managing device 300. Each of the excavator 100, the assisting device 200, and the managing device 300 includes a communication device, and is directly or indirectly connected with each other via a mobile phone communication network, a satellite communication network, a short-range wireless communication network, or the like. The excavator 100, the assisting device 200, and the managing device 300 constituting the control system SYS may each be one or more in number. In the example of FIG. 13, the control system SYS includes one excavator 100, one assisting device 200, and one managing device 300.

[0194] The assisting device 200, which is a device to assist the control of the excavator 100, is typically a mobile terminal device, for example a computer such as a laptop PC, a tablet PC, or a smartphone carried by a worker at the work site. The assisting device 200 may be a computer that the operator of the excavator 100 carries with him / her. However, the assisting device 200 may be a stationary terminal device as well.

[0195] The managing device 300, which is a device to manage various types of information, is typically a stationary terminal device such as, for example, a server computer installed in a management center outside the work site. The managing device 300 may be a portable computer (for example, a mobile terminal device such as a laptop PC, a tablet PC, or a smartphone).

[0196] At least one of the assisting device 200 and the managing device 300 may include a monitor and a remote operating device. In this case, the excavator 100 and at least one of the assisting device 200 and the managing device 300 constitute a remote excavator operation system. This enables a remote operator to operate the excavator 100 using the remote operating device. The remote operating device is connected to the controller 30 through a communication network such as a mobile phone network, a satellite network, or a short-range wireless communication network. Structured thus, the control system SYS may be configured such that a user of the assisting device 200 can intervene in the operation of the excavator 100 by the operator of the excavator 100 or by a remote operator. In this case, near the edge of the hole HL, for example, the user of the assisting device 200 can watch the positional relationship between the worker WK inside the hole HL and the bucket 6 of the excavator 100 and intervene in the operation of the excavator 100 if necessary, thereby ensuring the safety of the worker WK.

[0197] The controller 30 may be included in the assisting device 200 or in the managing device 300. Also, all or part of the functions performed by the controller 30 may be performed by the assisting device 200 or the managing device 300.

[0198] A preferred embodiment of the present disclosure has been described above in detail. However, the present disclosure is by no means limited to the embodiment described above; nor is it limited to the examples described below. The above and following embodiments may be subject to various alterations, substitutions, and so forth, without departing from the scope of the present disclosure. Also, features described separately herein can be combined unless a technical contradiction arises.

[0199] For example, in the above-described embodiment, the controller 30 is configured to prevent or substantially prevent movement of a driven element when it is determined that a job is taking place at a predetermined work site; however, the controller 30 may be configured to facilitate the movement of the driven element as well.

[0200] Facilitating the movement of a driven element may be implemented by, for example, facilitating the rise of the main pumps 14, that is, by switching the characteristics of flow-rate control illustrated in FIG. 8 to the characteristics of flow-rate control illustrated in FIG. 6. Alternatively, facilitating the movement of a driven element may be implemented by increasing the maximum operating speed of the driven element, increasing the relief pressure of a relief valve (not shown) provided in the center bypass pipeline CB, increasing the output power (the number of rotations per unit time) of a drive source such as the engine 11 or an electric motor, switching the operation mode of the excavator 100, and so forth.

[0201] Also, the above-described embodiment discloses hydraulic operating levers equipped with hydraulic pilot circuits. For example, assuming that a hydraulic pilot circuit is associated with the left operating lever 26L, the hydraulic oil to be supplied from the pilot pump 15 to the left operating lever 26L is transmitted to the pilot port of the control valve 176 at a flow rate to suit the opening of a remote-control valve, which is opened and closed by tilting the left operating lever 26L in an arm-opening direction. Alternatively, assuming that a hydraulic pilot circuit is associated with the right operating lever 26R, the hydraulic oil to be supplied from the pilot pump 15 to the right operating lever 26R is transmitted to the pilot port of the control valve 175, at a flow rate that suits the opening of a remote-control valve, which is opened or closed by tilting the right operating lever 26R in a boom-raising direction.

[0202] However, instead of such hydraulic operating levers with hydraulic pilot circuits, an electrical operating system with electric operating levers may be introduced. In this case, for example, the amount in which an electric operating lever is operated may be input to the controller 30 in the form of an electric signal. In addition, a solenoid valve may be positioned between the pilot pump 15 and each control valve's pilot port. Each solenoid valve may be configured to work based on electric signals from the controller 30. By means of this structure and configuration, when an electric operating lever is operated manually, the controller 30 may control the solenoid valve by an electric signal that suits the amount in which the lever is operated, and increase or decrease the pilot pressure. This allows each control valve (each spool valve) to be moved to a desired position.

[0203] When an electrical operating system equipped with electric operating levers is employed, the controller 30 can switch between manual control mode and auto control mode with ease. In manual control mode, the actuators are operated in response to manual operations that the operator performs on the operating devices 26. In auto control mode, the actuators are operated independently of manual operations. When the controller 30 switches from manual control mode to auto control mode, multiple control valves (spool valves) may be controlled individually in response to electric signals corresponding to the amount of one electric operating lever's operation.

[0204] This application is based on and claims priority to Japanese Patent Application No. 2022-061307, filed on March 31, 2022, the entire contents of which are incorporated herein by reference.LIST OF REFERENCE NUMERALS

[0205] 1 ... lower traveling body 1C ... crawler 1CL ... left crawler 1CR ... right crawler 2 ... rotating mechanism 2A ... rotation hydraulic motor 2M ... drive hydraulic motor 2ML ... left drive hydraulic motor 2MR ... right drive hydraulic motor 3 ... upper rotating body 4 ... boom 5 ... arm 6 ... bucket 7 ... boom cylinder 8 ... arm cylinder 9 ... bucket cylinder 10 ... cabin 11 ... engine 13 ... pump regulator 14 ... main pump 15 ... pilot pump 17 ... control valve unit 18 ... aperture 19 ... control pressure sensor 26 ... operating device 26D ... drive lever 26DL ... left drive lever 26DR ... right drive lever 26L ... left operating lever 26R ... right operating lever 28 ... discharge pressure sensor 29 ... operation sensor 30 ... controller 31 ... proportional valve 40 ... display device 50 ... aircraft 55 ... pole 60 ... control valve 70 ... object detection device 70A ... attachment camera 70B ... rear camera 70D ... camera 70F ... front camera 70L ... left camera 70P ... fixed camera 70R ... right camera 85 ... positioning device 100 ... excavator 171 to 176 ... control valve 200 ... assisting device 300 ... managing device CD1 ... pilot line 51 ... boom angle sensor S2 ... arm angle sensor S3 ... bucket angle sensor S4 ... body inclination sensor S5 ... rotating angular velocity sensor SYS ... control system

Claims

1. An excavator comprising: a lower traveling body; an upper rotating body mounted on the lower traveling body; an attachment mounted on the upper rotating body; and an actuator configured to move the attachment, wherein the excavator is configured such that movement of the actuator is controlled at a predetermined work site.

2. The excavator according to claim 1, wherein the excavator is further configured such that the movement of the actuator is facilitated, prevented, or substantially prevented at the predetermined work site.

3. The excavator according to claim 1, wherein the excavator is further configured such that the movement of the actuator is prevented or substantially prevented when an object is detected around an end attachment.

4. The excavator according to claim 1, wherein whether or not the excavator is at the predetermined work site is determined based on information obtained by an information obtaining device, and wherein, when the excavator is determined to be at the predetermined work site, the movement of the actuator is facilitated, prevented, or substantially prevented.

5. The excavator according to claim 4, wherein whether or not the excavator is at the predetermined work site is determined based on location information obtained by a positioning device serving as the information obtaining device, and wherein, when the excavator is determined to be at the predetermined work site, the movement of the actuator is facilitated, prevented, or substantially prevented.

6. The excavator according to claim 4, wherein whether or not the excavator is at the predetermined work site is determined based on an image captured by an image-capturing device serving as the information obtaining device, and wherein, when the excavator is determined to be at the predetermined work site, the movement of the actuator is facilitated, prevented, or substantially prevented.

7. The excavator according to claim 3, wherein the object around the end attachment is detected based on an image captured by an image-capturing device attached to the attachment.

8. The excavator according to claim 3, wherein, when a worker is detected around the end attachment, an alert is issued to at least one of an operator or the worker.

9. The excavator according to claim 1, wherein the actuator is a hydraulic actuator, and wherein movement of the hydraulic actuator is facilitated, prevented, or substantially prevented by controlling movement of at least one of: a hydraulic pump configured to supply hydraulic oil to the hydraulic actuator; a control valve configured to control a flow rate of hydraulic oil that flows into the hydraulic actuator; or a drive source configured to drive the hydraulic pump.

10. The excavator according to claim 1, wherein the movement of the actuator is facilitated by: increasing a maximum operating speed of the actuator; increasing a relief pressure of a relief valve provided in a center bypass pipeline; increasing an output power of a drive source; or switching an operation mode of the excavator.

11. The excavator according to claim 1, wherein the movement of the actuator is prevented or substantially prevented by: stopping the actuator; lowering a maximum operating speed of the actuator; lowering a relief pressure of a relief valve provided in a center bypass pipeline; lowering an output power of a drive source; or switching an operation mode of an excavator.

12. An excavator control system comprising: a lower traveling body; an upper rotating body mounted on the lower traveling body; an attachment mounted on the upper rotating body; and an actuator configured to move the attachment, wherein the excavator control system is configured such that, when an object is detected around an end attachment at a predetermined work site, movement of the actuator is prevented or substantially prevented.

13. A remote excavator operation system for an excavator having: a lower traveling body; an upper rotating body mounted on the lower traveling body; an attachment mounted on the upper rotating body; and an actuator configured to move the attachment, wherein the remote excavator operation system is configured such that, when an object is detected around an end attachment at a predetermined work site, movement of the actuator is prevented or substantially prevented.

Images