Shovel and shovel control device

Abstract

The invention relates to a shovel and a control device of the shovel, which can restrain operation deviation. A shovel (100) according to the present invention is provided with a lower traveling body (1), an upper rotating body (3) rotatably mounted on the lower traveling body (1), and an attachment device (AT) attached to the upper rotating body (3), and a controller (30) of the shovel (100) is configured so as to repeatedly calculate an excavation reaction force on the basis of information relating to an excavation operation performed on a work object by the attachment device (AT) in a work site. Furthermore, the controller (30) is configured so as to set a target value on the basis of the excavation reaction force calculated during one or more excavation operations, and so as to control, on the basis of the target value, each excavation operation performed after the target value has been set.

Description

Technical Field

[0001] This application claims priority based on Japanese Patent Application No. 2023-218207 filed on December 25, 2023. The entire content of the Japanese application is incorporated herein by reference.

[0002] The present invention relates to an excavator and a control device for an excavator. Background Art

[0003] Conventionally, an excavator is known that controls the horsepower of a hydraulic pump according to the posture of an attachment (see Patent Document 1).

[0004] Patent Document 1: International Publication No. 2017 / 131189

[0005] The above-described excavator is configured to be able to improve operability and fuel consumption efficiency by performing optimal output control corresponding to the posture of the attachment.

[0006] However, the excavation operation performed by the above-described excavator is affected by the state of the ground sand and soil. Since the bucket 6 is underground during the excavation operation, the state of the bucket 6 cannot be grasped from the ground surface side (air). Therefore, the above-described excavator cannot suppress the deviation of the excavation amount (volume or weight of the excavated sand and soil, etc.) achieved by each excavation operation, and there is a possibility of reducing the work efficiency. Summary of the Invention

[0007] Therefore, it is desired to provide a control device for an excavator that can suppress work deviation.

[0008] The control device for an excavator according to an embodiment of the present invention is such that the excavator has a lower traveling body, an upper swing body rotatably mounted on the lower traveling body, and an attachment mounted on the upper swing body. Among them, the excavation reaction force is repeatedly calculated based on information related to the excavation operation of the work object by the attachment at the work site, a target value is set based on the excavation reaction force calculated during one or more excavation operations, and each excavation operation performed after setting the target value related to the excavation reaction force is supported based on the target value related to the excavation reaction force.

[0009] Advantages of the Invention

[0010] The above-described control device for an excavator can suppress work deviation. Brief Description of the Drawings

[0011] Figure 1 It is a side view of an excavator.

[0012] Figure 2 It is a diagram schematically showing a structural example of a control system of an excavator.

[0013] Figure 3 It is a diagram schematically showing a structural example of the hydraulic system of an excavator.

[0014] Figure 4A It is a diagram of a part of the hydraulic system related to the operation of the arm cylinder.

[0015] Figure 4B It is a diagram of a part of the hydraulic system related to the operation of the boom cylinder.

[0016] Figure 4C It is a diagram of a part of the hydraulic system related to the operation of the bucket cylinder.

[0017] Figure 4D It is a diagram of a part of the hydraulic system related to the operation of the swing hydraulic motor.

[0018] Figure 4E It is a diagram of a part of the hydraulic system related to the operation of the left travel hydraulic motor.

[0019] Figure 4F It is a diagram of a part of the hydraulic system related to the operation of the right travel hydraulic motor.

[0020] Figure 5 It is a diagram explaining the process of the loading operation performed by the excavator.

[0021] Figure 6 It is a flowchart showing an example of the process of the setting process.

[0022] Figure 7 It is a flowchart showing an example of the process of the support process.

[0023] Figure 8 It is a schematic diagram showing another structural example of the control system of the excavator.

[0024] Explanation of symbols

[0025] 1 - Lower traveling body, 2 - Swing mechanism, 2A - Swing hydraulic motor, 2M - Traveling hydraulic motor, 2ML - Left traveling hydraulic motor, 2MR - Right traveling hydraulic motor, 3 - Upper swing body, 4 - Boom, 5 - Arm, 6 - Bucket, 7 - Boom cylinder, 8 - Arm cylinder, 9 - Bucket cylinder, 10 - Cab, 11 - Engine, 13 - Regulator, 14 - Main pump, 15 - Pilot pump, 17 - Control valve unit, 18L - Left throttle, 18R - Right throttle, 19L - Left control pressure sensor, 19R - Right control pressure sensor, 26 - Operating device, 26D - Traveling operating device, 26DL - Left traveling lever, 26DR - Right traveling lever, 26L - Left operating lever, 26R - Right operating lever, 28 - Discharge pressure sensor, 29, 29DL, 29DR, 29LA, 29LB, 29RA, 29RB - Operating sensors, 30 - Controller, 31, 31AL~31FL, 31AR~31FR - Solenoid valves, 40 - Display device, 42 - Input device, 42a - Mode switch, 43 - Sound output device, 47 - Storage device, 50 - Equipment guidance unit, 51 - Position calculation unit, 52 - Distance calculation unit, 53 - Information transmission unit, 54 - Automatic control unit, 55 - Excavation reaction force calculation unit, 56 - Target setting unit, 57 - Excavation control unit, 100 - Excavator, 171~176 - Control valves, 200 - Support device, 300 - Management device, AT - Attachment device, Q1 - Positioning device, S1 - Boom angle sensor, S2 - Arm angle sensor, S3 - Bucket angle sensor, S4 - Machine body tilt sensor, S5 - Swing state sensor, S6 - Imaging device, S6B, S6F, S6L, S6R - Cameras, S7B - Boom base pressure sensor, S7R - Boom rod pressure sensor, S8B - Arm base pressure sensor, S8R - Arm rod pressure sensor, S9B - Bucket base pressure sensor, S9R - Bucket rod pressure sensor, SW, SW1, SW2 - Switches, SYS - Control system, T1 - Communication device. Detailed implementation mode

[0026] Hereinafter, with reference to the drawings, the excavator 100 according to the embodiment of the present invention will be described. First, with reference to Figure 1 , an overview of the excavator 100 will be described. Figure 1 FIG. is a side view of the excavator 100.

[0027] The excavator 100 includes: a lower traveling body 1; an upper swing body 3 that is rotatably mounted on the lower traveling body 1 via a swing mechanism 2; a boom 4, an arm 5, and a bucket 6 that constitute an excavation attachment device as an example of an attachment device AT; and a cab 10.

[0028] The lower traveling body 1 is driven by traveling hydraulic motors 2M (refer to Figure 2)The excavator 100 is driven to travel by a pair of left and right crawlers driven hydraulically. The travel hydraulic motor 2M includes a left travel hydraulic motor 2ML and a right travel hydraulic motor 2MR. That is, the left travel hydraulic motor 2ML and the right travel hydraulic motor 2MR drive the lower traveling body 1 (crawler) as the driven part.

[0029] The upper slewing body 3 is slewed relative to the lower traveling body 1 by being driven by a slewing hydraulic motor 2A (refer to Figure 2 ). That is, the slewing hydraulic motor 2A is a slewing drive part that drives the upper slewing body 3 as the driven part, and can change the orientation of the upper slewing body 3.

[0030] In addition, the upper slewing body 3 can be electrically driven by a slewing electric motor as an electric actuator instead of the slewing hydraulic motor 2A. That is, similarly to the slewing hydraulic motor 2A, the slewing electric motor is a slewing drive part that drives the upper slewing body 3 as the driven part, and can change the orientation of the upper slewing body 3.

[0031] The boom 4 is rotatably mounted at the front center of the upper slewing body 3, the arm 5 is rotatably mounted at the front end of the boom 4, and the bucket 6 as an end attachment is rotatably mounted at the front end of the arm 5. The boom 4, the arm 5, and the bucket 6 are respectively hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9 as hydraulic actuators.

[0032] In addition, the bucket 6 is an example of an end attachment, and other end attachments, such as a bucket for slopes, a bucket for dredging, or a breaker, can be installed at the front end of the arm 5 instead of the bucket 6 according to the work content, etc.

[0033] The cab 10 is a cockpit for an operator to ride in, and is provided on the front left side of the upper slewing body 3.

[0034] Next, in addition to referring to Figure 1 , reference is also made to Figure 2 to describe the specific structure of the excavator 100. Figure 2 is a diagram schematically showing a structural example of the control system of the excavator 100. In addition, in Figure 2 , the mechanical power transmission pipeline, the working oil pipeline, the pilot pipeline, and the electrical signal pipeline are shown by double lines, solid lines, dotted lines, and dashed lines, respectively.

[0035] The drive system of the excavator 100 includes an engine 11, a regulator 13, a main pump 14, and a control valve unit 17. And, the hydraulic drive system of the excavator 100 includes hydraulic actuators such as a travel hydraulic motor 2M, a slewing hydraulic motor 2A, a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9 that respectively hydraulically drive the lower traveling body 1, the upper slewing body 3, the boom 4, the arm 5, and the bucket 6.

[0036] The engine 11 is the power source in the hydraulic drive system. For example, it is mounted at the rear of the upper swing body 3. Specifically, the engine 11 rotates constantly at a preset target speed under the direct or indirect control of the controller 30, and drives the main pump 14 and the pilot pump 15. The engine 11 is, for example, a diesel engine. Additionally, the power source can also be an electric motor. In this case, in the excavator 100, a power storage device (battery) can be mounted, or a power generation device such as a fuel cell can be mounted.

[0037] The regulator 13 controls the discharge volume of the main pump 14. For example, the regulator 13 adjusts the angle (deflection angle) of the swash plate of the main pump 14 according to the control instruction from the controller 30. The regulator 13 includes, for example, a left regulator 13L and a right regulator 13R (refer to Figure 3 ).

[0038] The main pump 14 is, for example, mounted at the rear of the upper swing body 3, and supplies working oil to the control valve unit 17 through the working oil pipeline. The main pump 14 is driven by the engine 11. The main pump 14 is, for example, a variable-capacity hydraulic pump, and adjusts the stroke length of the piston by adjusting the deflection angle of the swash plate under the control of the controller 30, thereby controlling the discharge flow rate (displacement). The main pump 14 includes, for example, a left main pump 14L and a right main pump 14R (refer to Figure 3 ).

[0039] The control valve unit 17 is, for example, mounted at the center of the upper swing body 3, and is a hydraulic control device that controls the hydraulic drive system according to the operation performed by the operator on the operation device 26. The control valve unit 17 is connected to the main pump 14 via the working oil pipeline, and selectively supplies the working oil supplied from the main pump 14 to each of a plurality of hydraulic actuators (travel hydraulic motor 2M, swing hydraulic motor 2A, boom cylinder 7, arm cylinder 8, and bucket cylinder 9) according to the operation state of the operation device 26. Specifically, the control valve unit 17 includes control valves 171 to 176 that control the flow rate and flow direction of the working oil supplied from the main pump 14 to each hydraulic actuator. More specifically, the control valve 171 corresponds to the left travel hydraulic motor 2ML, the control valve 172 corresponds to the right travel hydraulic motor 2MR, and the control valve 173 corresponds to the swing hydraulic motor 2A. And, the control valve 174 corresponds to the bucket cylinder 9, the control valve 175 corresponds to the boom cylinder 7, and the control valve 176 corresponds to the arm cylinder 8. The control valve 175 includes, for example, a control valve 175L and a control valve 175R, and the control valve 176 includes, for example, control valves 176L, 176R (refer to Figure 3 ).

[0040] The operating system of the excavator 100 includes a pilot pump 15 and an operation device 26. And, the operating system of the excavator 100 includes a solenoid valve 31 as a structure related to the device control function based on the controller 30.

[0041] The pilot pump 15 is mounted, for example, at the rear of the upper swing body 3 and supplies pilot pressure to the pilot ports of the control valves 171 to 176 via pilot piping. The pilot pump 15 is, for example, a fixed-displacement hydraulic pump and is driven by the engine 11.

[0042] The operating device 26 is provided near the driver's seat in the cab 10 and is an operation input mechanism for the operator to operate various operation elements (the lower traveling body 1, the upper swing body 3, the boom 4, the arm 5, the bucket 6, etc.). In other words, the operating device 26 is an operation input mechanism for the operator to operate the hydraulic actuators (the traveling hydraulic motor 2M, the swing hydraulic motor 2A, the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, etc.) that drive the respective operation elements. Pilot pressure corresponding to the operation content (operation direction and operation amount) of the operating device 26 is input to the pilot ports of the control valves 171 to 176. In the illustrated example, the operating device 26 includes: a left operating lever 26L (refer to Figure 4A ), which is a lever device for operating the upper swing body 3 (the swing hydraulic motor 2A) and the arm 5 (the arm cylinder 8); a right operating lever 26R (refer to Figure 4B ), which is a lever device for operating the boom 4 (the boom cylinder 7) and the bucket 6 (the bucket cylinder 9); and a traveling operating device 26D (refer to Figure 4E ), which operates the crawlers of the lower traveling body 1 (the traveling hydraulic motor 2M). The traveling operating device 26D includes a left traveling lever 26DL (refer to Figure 4E ) for operating the left crawler (the left traveling hydraulic motor 2ML) and a right traveling lever 26DR (refer to Figure 4F ) for operating the right crawler (the right traveling hydraulic motor 2MR). The traveling operating device 26D may include a left traveling pedal for operating the left crawler (the left traveling hydraulic motor 2ML) and a right traveling pedal for operating the right crawler (the right traveling hydraulic motor 2MR).

[0043] In the illustrated example, the operating device 26 is an electric type that outputs an electric signal. The electric signal from the operating device 26 is input to the controller 30, and the controller 30 controls the pilot pressure applied to the respective pilot ports of the control valves 171 to 176 based on the input electric signal, thereby realizing the operation of various hydraulic actuators corresponding to the operation content of the operating device 26. Specifically, solenoid valves 31 that operate based on an electric signal from the controller 30 are arranged between the pilot pump 15 and the respective pilot ports of the control valves 171 to 176. And when the operating device 26 is operated, the controller 30 controls the solenoid valves 31 based on an electric signal corresponding to its operation amount (for example, joystick operation amount) to increase or decrease the pilot pressure, thereby enabling the control valves 171 to 176 to operate respectively according to the operation content of the operating device 26. In addition, the control valves 171 to 176 may be electromagnetic solenoid type spool valves that are driven according to an instruction from the controller 30.

[0044] The control system of the excavator 100 includes a controller 30, a discharge pressure sensor 28, an operation sensor 29, solenoid valves 31, a display device 40, an input device 42, a sound output device 43, a storage device 47, a boom angle sensor S1, an arm angle sensor S2, a bucket angle sensor S3, a body tilt sensor S4, a swing state sensor S5, a camera device S6, a positioning device Q1, and a communication device T1.

[0045] The controller 30 (an example of a control device) is configured to be provided in the cab 10 and perform drive control of the excavator 100. The functions of the controller 30 can be realized by any hardware, software, or a combination thereof. In the illustrated example, the controller 30 is mainly configured by a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a non-volatile auxiliary storage device, and various input / output interfaces. The controller 30 realizes various functions, for example, by executing various programs stored in the ROM or the non-volatile auxiliary storage device on the CPU.

[0046] In the illustrated example, the controller 30 sets a target rotational speed according to a work mode or the like preset by a prescribed operation by an operator or the like, and performs drive control to make the engine 11 rotate constantly. The controller 30 can output a control instruction to the regulator 13 as needed to change the discharge amount of the main pump 14.

[0047] The controller 30 can be configured to perform control related to a device guidance function that guides (directs) manual operations of the excavator 100 by an operator via the operating device 26. Further, the controller 30 can be configured to perform control related to a device control function that automatically supports the manual operations of the excavator 100 by the operator via the operating device 26. At this time, the controller 30 can include a device guidance unit 50 as a functional unit related to the device guidance function and the device control function.

[0048] In addition, a part of the functions of the controller 30 can also be implemented by another controller (control device). That is, the functions of the controller 30 can be implemented in a distributed manner by a plurality of controllers. For example, the device guidance function and the device control function can also be implemented by a dedicated controller (control device).

[0049] The discharge pressure sensor 28 detects the discharge pressure of the main pump 14. A detection signal corresponding to the discharge pressure detected by the discharge pressure sensor 28 is input to the controller 30. The discharge pressure sensor 28 includes, for example, a left discharge pressure sensor 28L and a right discharge pressure sensor 28R (refer to Figure 3 ).

[0050] The operation sensor 29 detects the operation content (operation direction and operation amount) of the operating device 26. The detection signal of the operation sensor 29 is input to the controller 30. The operation sensor 29 includes, for example, an operation sensor 29LA that detects the operation content in the front-rear direction (arm operation direction) of the left operation lever 26L (refer to Figure 4A ), an operation sensor 29RA that detects the operation content in the front-rear direction (boom operation direction) of the right operation lever 26R (refer to Figure 4B ), an operation sensor 29RB that detects the operation content in the left-right direction (bucket operation direction) of the right operation lever 26R (refer to Figure 4C ), an operation sensor 29LB that detects the operation content in the left-right direction (slewing operation direction) of the left operation lever 26L (refer to Figure 4D ), an operation sensor 29DL that detects the operation content of the left travel lever 26DL (refer to Figure 4E ) and an operation sensor 29DR that detects the operation content of the right travel lever 26DR (refer to Figure 4F ).

[0051] In the illustrated example, the operation sensor 29 is an inclination sensor that can detect the operation amount (tilt amount) and the tilt direction of the operating device 26, but it can also be any sensor such as an encoder or a potentiometer.

[0052] The solenoid valve 31 is disposed in a pilot pipe line connecting the pilot pump 15 to the respective pilot ports of the control valves 171 to 176, and is configured to be able to change its flow path area (the cross-sectional area through which the working oil can pass). The solenoid valve 31 operates according to a control command input from the controller 30. Thus, even when the operator does not operate the operating device 26, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the respective pilot ports of the control valves 171 to 176 via the solenoid valve 31. In the illustrated example, as Figures 4A - 4F shown, the solenoid valve 31 includes solenoid valves 31AL to 31FL and solenoid valves 31AR to 31FR.

[0053] The display device 40 is disposed at a place that is easily visually recognizable by an operator sitting on the driver's seat in the cab 10, and displays various information under the control of the controller 30. The display device 40 can be connected to the controller 30 via an in-vehicle communication network, or can be connected to the controller 30 via a one-to-one dedicated line.

[0054] The input device 42 is disposed within the reach of an operator sitting on the driver's seat in the cab 10, receives various operation inputs made by the operator, and outputs a signal corresponding to the operation input to the controller 30. The input device 42 is, for example, a touch panel mounted on the screen of the display device 40 that displays various information, a knob switch provided at the front end of the lever portion of the lever device, a button switch provided around the display device 40, a lever, a changeover switch, or a rotary control dial, etc. A signal corresponding to the operation of the input device 42 is input to the controller 30.

[0055] Further, the input device 42 has a mode switch 42a. The mode switch 42a is a switch for switching the operation mode of the excavator 100. The operation mode indicates the operation category based on the excavator 100, and includes, for example, a crane mode and a normal mode, etc. In addition, the mode switch 42a can be a software switch displayed on the screen of the display device 40, can be a hardware switch provided around the display device 40, or can also be a switch provided at another position in the cab 10.

[0056] The sound output device 43 is, for example, disposed in the cab 10, is connected to the controller 30, and outputs sound under the control of the controller 30. The sound output device 43 is, for example, a speaker or a buzzer, etc. The sound output device 43 auditorily outputs various information according to a sound output command from the controller 30.

[0057] The storage device 47 is provided, for example, inside the cab 10 and stores various information under the control of the controller 30. The storage device 47 is, for example, a non-volatile storage medium such as a semiconductor memory. The storage device 47 can store the information output by various devices during the operation of the excavator 100, and can also store the information acquired via various devices before the excavator 100 starts operating. The storage device 47 can, for example, store data related to the target point acquired via the communication device T1 or the like or set via the input device 42 or the like. The target point is, for example, a point on the target construction surface. The data related to the target point can be set (saved) by the operator of the excavator 100 or can also be set by the construction manager or the like.

[0058] The boom angle sensor S1 is mounted on the boom 4 and detects the rotation angle of the boom 4 relative to the upper swing body 3 (hereinafter referred to as "boom angle"), for example, the angle formed by the straight line connecting the two end points (the center points of the connecting pins) of the boom 4 and the rotation plane of the upper swing body 3 (a plane perpendicular to the rotation axis) when viewed from the side. The boom angle sensor S1 is, for example, a rotary encoder, an acceleration sensor, a 6-axis sensor, an IMU (Inertial Measurement Unit), or a combination thereof, etc. Also, the boom angle sensor S1 can also be composed of a potentiometer using a variable resistor, a cylinder sensor that detects the stroke amount of the hydraulic cylinder (boom cylinder 7) corresponding to the boom angle, etc. The same applies to the arm angle sensor S2 and the bucket angle sensor S3. The detection signal corresponding to the boom angle based on the boom angle sensor S1 is input to the controller 30.

[0059] The arm angle sensor S2 is mounted on the arm 5 and detects the rotation angle of the arm 5 relative to the boom 4 (hereinafter referred to as "arm angle"), for example, the angle formed by the straight line connecting the two end points (the center points of the connecting pins) of the arm 5 and the straight line connecting the two end points (the center points of the connecting pins) of the boom 4 when viewed from the side. The detection signal corresponding to the arm angle detected by the arm angle sensor S2 is input to the controller 30.

[0060] The bucket angle sensor S3 is mounted on the bucket 6 and detects the rotation angle of the bucket 6 relative to the arm 5 (hereinafter referred to as "bucket angle"), for example, the angle formed by the straight line connecting the fulcrum (the center point of the connecting pin) and the front end (the bucket tip) of the bucket 6 and the straight line connecting the two end points (the center points of the connecting pins) of the arm 5 when viewed from the side. The detection signal corresponding to the bucket angle detected by the bucket angle sensor S3 is input to the controller 30. Additionally, the bucket angle sensor S3 can also be omitted.

[0061] The body tilt sensor S4 detects the tilt state of the body (the upper slewing body 3 or the lower traveling body 1) relative to the horizontal plane. The body tilt sensor S4 is installed, for example, on the upper slewing body 3, and detects the tilt angles (hereinafter referred to as "front-back tilt angle" and "left-right tilt angle") of the excavator 100 (i.e., the upper slewing body 3) around two axes in the front-back direction and the left-right direction. The body tilt sensor S4 is, for example, a rotary encoder, an acceleration sensor, a 6-axis sensor, an IMU, or a combination thereof. Detection signals corresponding to the tilt angles (front-back tilt angle and left-right tilt angle) detected by the body tilt sensor S4 are input to the controller 30.

[0062] The slewing state sensor S5 outputs information related to the slewing state of the upper slewing body 3. The slewing state sensor S5 detects, for example, the slewing angular velocity of the upper slewing body 3. The slewing state sensor S5 can also detect the slewing angle. The slewing state sensor S5 is, for example, a gyro sensor, a resolver, or a rotary encoder. Detection signals corresponding to the slewing angular velocity of the upper slewing body 3 by the slewing state sensor S5 are input to the controller 30.

[0063] The imaging device S6 as a space recognition device images the periphery of the excavator 100. In the illustrated example, the imaging device S6 includes a camera S6F that captures the front of the excavator 100, a camera S6L that captures the left side of the excavator 100, a camera S6R that captures the right side of the excavator 100, and a camera S6B that captures the rear of the excavator 100. In addition, the imaging device S6 can also be directly communicably connected to the controller 30.

[0064] In the illustrated example, the camera S6F is installed on the ceiling of the cab 10, that is, inside the cab 10. The camera S6F can also be installed outside the cab 10, such as on the roof of the cab 10 or the side of the boom 4. The camera S6L is installed at the left end of the upper surface of the upper slewing body 3, the camera S6R is installed at the right end of the upper surface of the upper slewing body 3, and the camera S6B is installed at the rear end of the upper surface of the upper slewing body 3.

[0065] The imaging device S6 (camera S6F, camera S6B, camera S6L, and camera S6R) are respectively, for example, monocular wide-angle cameras with a wide field of view. The imaging device S6 can respectively be a stereo camera or a distance image camera. The captured images captured by the imaging device S6 are input to the controller 30 via the display device 40.

[0066] The imaging device S6, which serves as a space recognition device, can function as an object detection device. At this time, the imaging device S6 can detect objects existing around the excavator 100. Among the objects to be detected, for example, it can include people, animals, vehicles, construction machinery, buildings, and depressions. The imaging device S6, which serves as an object detection device, can also calculate the distance from the imaging device S6 or the excavator 100 to the identified object. The imaging device S6, which serves as an object detection device, can be a stereo camera or a distance image sensor, etc. Specifically, the imaging device S6 is a monocular camera having an imaging element such as a CCD or a CMOS, and outputs the captured image to the display device 40.

[0067] In the excavator 100, in addition to the imaging device S6, as a space recognition device, for example, other object detection devices such as an ultrasonic sensor, a millimeter wave radar, a LIDAR, and an infrared sensor can also be provided. The millimeter wave radar, ultrasonic sensor, or lidar, etc., which serves as a space recognition device, can also emit a plurality of signals (such as laser beams) to an object and receive the reflected signals, thereby detecting the distance and direction of the object based on the reflected signals.

[0068] A boom rod pressure sensor S7R and a boom bottom pressure sensor S7B are installed in the boom cylinder 7. A stick rod pressure sensor S8R and a stick bottom pressure sensor S8B are installed in the stick cylinder 8. A bucket rod pressure sensor S9R and a bucket bottom pressure sensor S9B are installed in the bucket cylinder 9. The boom rod pressure sensor S7R, the boom bottom pressure sensor S7B, the stick rod pressure sensor S8R, the stick bottom pressure sensor S8B, the bucket rod pressure sensor S9R, and the bucket bottom pressure sensor S9B are collectively referred to as "cylinder pressure sensors".

[0069] The boom rod pressure sensor S7R detects the pressure in the rod side oil chamber of the boom cylinder 7 (hereinafter referred to as "boom rod pressure"). The boom bottom pressure sensor S7B detects the pressure in the bottom side oil chamber of the boom cylinder 7 (hereinafter referred to as "boom bottom pressure"). The stick rod pressure sensor S8R detects the pressure in the rod side oil chamber of the stick cylinder 8 (hereinafter referred to as "stick rod pressure"). The stick bottom pressure sensor S8B detects the pressure in the bottom side oil chamber of the stick cylinder 8 (hereinafter referred to as "stick bottom pressure"). The bucket rod pressure sensor S9R detects the pressure in the rod side oil chamber of the bucket cylinder 9 (hereinafter referred to as "bucket rod pressure"). The bucket bottom pressure sensor S9B detects the pressure in the bottom side oil chamber of the bucket cylinder 9 (hereinafter referred to as "bucket bottom pressure").

[0070] The positioning device Q1 is configured to measure the position of the upper rotating body 3. In the illustrated example, the positioning device Q1 is a GNSS (Global Navigation Satellite System) compass that detects the position and orientation of the upper rotating body 3, and a detection signal corresponding to the position and orientation of the upper rotating body 3 is input to the controller 30. Additionally, the orientation of the upper rotating body 3 can also be detected by other devices such as an azimuth sensor installed on the upper rotating body 3.

[0071] The communication device T1 is configured to communicate with an external device via an arbitrary communication network including a mobile communication network, a satellite communication network, or the Internet, etc. Specifically, the communication device T1 can be composed of a mobile communication module corresponding to mobile communication standards such as LTE (Long Term Evolution), 4G (4th Generation), or 5G (5th Generation), or a satellite communication module for connecting to a satellite communication network, etc.

[0072] The equipment guidance unit 50 is configured to perform an equipment guidance function. In the illustrated example, the equipment guidance unit 50 conveys operation information such as the distance between a target point and a control point (e.g., the working part of the terminating accessory device) to the operator through the display device 40 or the sound output device 43, etc. Data related to the target point is pre-stored in the storage device 47. The data related to the target point is expressed in a reference coordinate system. The reference coordinate system is, for example, the World Geodetic System. The World Geodetic System is a three-dimensional orthogonal XYZ coordinate system with the center of gravity of the earth as the origin, the direction of the intersection of the Greenwich meridian and the equator as the X-axis, the direction of 90 degrees east longitude as the Y-axis, and the direction of the North Pole as the Z-axis. After the operator determines an arbitrary point at the construction site as a reference point through the input device 42, the relative positional relationship between the reference point and the target point can be set. The working part of the terminating accessory device is, for example, the tip of the bucket 6 or the back surface of the bucket 6, etc. The equipment guidance unit 50 notifies the operator of the operation information through the display device 40 or the sound output device 43, etc., and guides the operation of the excavator 100 performed by the operator through the operation device 26.

[0073] Furthermore, the equipment guidance unit 50 can be configured to perform an equipment control function. For example, when the operator operates manually, the equipment guidance unit 50 can cause at least one of the swing hydraulic motor 2A, the travel hydraulic motor 2M, the boom 4, the arm 5, and the bucket 6 to automatically operate so that the target point coincides with the control point (a point on the working part of the terminating accessory device).

[0074] In the illustrated example, the equipment guidance unit 50 obtains information from the boom angle sensor S1, the arm angle sensor S2, the bucket angle sensor S3, the body tilt sensor S4, the slewing state sensor S5, the imaging device S6, the positioning device Q1, the communication device T1, the input device 42, and the like. And, based on the information obtained, the equipment guidance unit 50 calculates the distance between the target point and the control point, and notifies the operator of the magnitude of the distance between the target point and the control point through the sound from the sound output device 43 and the image displayed on the display device 40, or automatically controls the operation of the actuator to make the control point coincide with the target point. The equipment guidance unit 50 includes a position calculation unit 51, a distance calculation unit 52, an information transmission unit 53, an automatic control unit 54, an excavation reaction force calculation unit 55, a target setting unit 56, and an excavation control unit 57 as functional components related to the equipment guidance function and the equipment control function.

[0075] The position calculation unit 51 calculates the position of a specified positioning object. For example, the position calculation unit 51 calculates the coordinates of the control point in the reference coordinate system. Specifically, the position calculation unit 51 calculates the coordinates of the control point based on the traveling distance of the lower traveling body 1, the slewing angle of the upper slewing body 3, and the respective rotation angles (boom angle, arm angle, and bucket angle) of the boom 4, the arm 5, and the bucket 6.

[0076] The distance calculation unit 52 is configured to calculate the distance between two positioning objects. In the illustrated example, the distance calculation unit 52 calculates the distance between the control point and the target point. For example, the distance calculation unit 52 calculates the distance between the control point on the tip of the bucket 6 and the point on the target construction surface.

[0077] The information transmission unit 53 transmits (notifies) various information to the operator of the excavator 100 through a notification mechanism such as the display device 40 or the sound output device 43. The information transmission unit 53 can notify the operator of the excavator 100 of the magnitudes of various distances calculated by the distance calculation unit 52. For example, the information transmission unit 53 can convey the magnitude of the distance between the control point and the target point to the operator using at least one of the visual information based on the display device 40 and the auditory information based on the sound output device 43.

[0078] Specifically, the information transmission unit 53 can use the intermittent sound of the sound output device 43 to convey the magnitude of the distance between the control point and the target point to the operator. At this time, the information transmission unit 53 can perform the following operations: the smaller the distance, the shorter the interval of the intermittent sound, and the larger the distance, the longer the interval of the intermittent sound. In addition, the information transmission unit 53 can use a continuous sound and can also represent the difference in the magnitude of the distance while changing the pitch or intensity of the sound, etc. Moreover, when the control point at the front end of the bucket 6 is located at a position lower than the target construction surface, that is, when it exceeds the target construction surface, the information transmission unit 53 can issue an alarm through the sound output device 43. This alarm is, for example, a continuous sound significantly louder than the intermittent sound.

[0079] In addition, the information transmission unit 53 can display the magnitude of the distance between the control point and the target point, etc. as operation information on the display device 40. The display device 40 can, under the control of the controller 30, display the operation information received from the information transmission unit 53 together with the image data received from the imaging device S6. The information transmission unit 53 can convey the magnitude of the distance to the operator by using an image of an analog gauge or an image of a bar graph indicator, etc.

[0080] The automatic control unit 54 automatically supports the manual operation of the excavator 100 by the operator through the operation device 26 by automatically operating the actuator. Specifically, the automatic control unit 54 can separately and automatically adjust the pilot pressure acting on the pilot ports of the control valves corresponding to the plurality of hydraulic actuators. Thereby, the automatic control unit 54 can automatically operate each hydraulic actuator. The control related to the equipment control function of the automatic control unit 54 can be executed, for example, when a specified switch included in the input device 42 is pressed. The specified switch is, for example, an equipment control switch (hereinafter referred to as "MC (Machine Control) switch"), and can also be arranged as a rotary switch at the front end of the grip portion of the operation device 26 (for example, as the boom operation lever for operating the boom 5). The equipment control function executed when the MC switch is pressed will be described below.

[0081] For example, when the automatic control unit 54 presses the MC switch or the like, in order to support the excavation operation, according to the movement of the arm cylinder 8 corresponding to the operation of the arm operation lever, at least one of the boom cylinder 7 and the bucket cylinder 9 is automatically extended or retracted. Specifically, when the operator manually performs the retraction operation of the arm 5 (hereinafter referred to as "arm retraction operation"), the automatic control unit 54 automatically extends or retracts at least one of the boom cylinder 7 and the bucket cylinder 9 so that the target point on the target construction surface coincides with the control point on the working part such as the tip or the back surface of the bucket 6. At this time, the operator can, for example, retract the arm 5 while making the tip of the bucket 6 coincide with the target construction surface only by operating the arm operation lever in the arm retraction direction.

[0082] The excavation reaction force calculation unit 55 is configured to derive the excavation reaction force. The excavation reaction force is the reaction force of the excavation force and is a force having the same magnitude as the excavation force and in the opposite direction to the excavation force. In the illustrated example, the excavation reaction force calculation unit 55 derives the excavation reaction force based on the posture of the excavation attachment and the load acting on the excavation attachment. The posture of the excavation attachment is detected by a posture sensor. The posture sensor includes a boom angle sensor S1, an arm angle sensor S2, and a bucket angle sensor S3. The load acting on the excavation attachment is detected by a cylinder pressure sensor. The cylinder pressure sensor includes a boom rod pressure sensor S7R, a boom bottom pressure sensor S7B, an arm rod pressure sensor S8R, an arm bottom pressure sensor S8B, a bucket rod pressure sensor S9R, and a bucket bottom pressure sensor S9B.

[0083] Specifically, the excavation reaction force calculation unit 55 repeatedly derives the excavation reaction force at a prescribed calculation cycle using a prescribed calculation formula. The excavation reaction force calculation unit 55 derives the excavation reaction force in such a manner that the deeper the excavation depth, that is, the greater the vertical distance between the ground contact surface of the excavator 100 and the tip of the bucket 6, the greater the excavation reaction force. And, the excavation reaction force calculation unit 55 derives the excavation reaction force in such a manner that the greater the depth of the tip of the bucket 6 with respect to the excavation target ground, that is, the ground penetration depth, the greater the excavation reaction force. And, the excavation reaction force calculation unit 55 can derive the excavation reaction force considering sand properties such as sand density. The sand properties can be a value input by the operator through the input device 42 or the like, or can be a value automatically calculated based on the outputs of various sensors such as the cylinder pressure sensor. And, the excavation reaction force calculation unit 55 can be configured to calculate at least one of the horizontal component and the vertical component of the excavation reaction force.

[0084] The target setting unit 56 is configured to set a target value related to the excavation action. In the illustrated example, the target setting unit 56 is configured to determine whether a prescribed excavation action suitable for calculating the target value has been performed based on information related to the excavation action performed by the attachment AT on the work object (excavation object ground) at the work site, and to set the target value based on the excavation reaction force calculated when the excavation action is determined to be the prescribed excavation action.

[0085] The information related to the excavation action is, for example, information related to the excavation amount, such as the amount of sand and soil taken into the bucket 6. Typically, the amount of sand and soil taken into the bucket 6 is the volume of sand and soil contained in the bucket 6 in the air after the excavation action is performed and before the dumping action is performed. The volume of sand and soil can be calculated, for example, based on the image of the bucket 6 in the air taken by the camera S6F. Alternatively, the amount of sand and soil taken into the bucket 6 can be estimated based on the image of the ground (the ground above the bucket 6 in the ground) taken by the camera S6F. Specifically, the amount of sand and soil can be estimated based on the state of the ground raised by the action of the bucket 6 in the second half of the excavation action (the action of the bucket 6 lifted from the ground by the boom lifting action). Alternatively, the amount of sand and soil taken into the bucket 6 can be estimated based on the image of the ground before the excavation action and the image of the ground after the excavation action taken by the camera S6F. Specifically, the amount of sand and soil can be estimated based on the change in the shape of the ground before and after the excavation action. Alternatively, the amount of sand and soil taken into the bucket 6 can be the weight of the sand and soil contained in the bucket 6. The weight of the sand can be calculated based on the output of the posture sensor and the output of the cylinder pressure sensor, for example.

[0086] When the amount of soil taken into the bucket 6 is acquired, the target setting unit 56 determines that a predetermined excavation action suitable for calculating a target value (target value of excavation reaction force) has been performed when it can be recognized that the bucket 6 is full of soil, or when it can be recognized that soil has been taken up to 80% or 90% of the capacity of the bucket 6, or when it can be recognized that the amount of soil (volume or weight) taken into the bucket 6 is greater than a predetermined amount (predetermined volume or predetermined weight). In this way, the target setting unit 56 sets a target value (target value of excavation reaction force) for determining whether the predetermined excavation action has been completed.

[0087] In addition, the information related to the excavation action may be information input by the operator of the shovel 100. The information input by the operator of the shovel 100 is, for example, information for notifying the controller 30 that the operator has determined that a predetermined excavation action has been performed. The operator of the shovel 100 can, for example, notify the controller 30 that the operator has determined that a predetermined excavation action has been performed by pressing a predetermined button as one of the input devices 42.

[0088] The specified excavation operation is an excavation operation suitable for calculating the target value. For example, it is an excavation operation that can fill the bucket 6 with sand, or an excavation operation that can take in sand until 80% or 90% of the capacity of the bucket 6.

[0089] The target value is a value used to reproduce the specified excavation operation. For example, it is the maximum value of the excavation reaction force (maximum excavation reaction force) calculated and recorded during the execution of the specified excavation operation. Additionally, the target value can be a value calculated based on the maximum value of the excavation reaction force. For example, the target value can be a value obtained by adding a specified value to the maximum value of the excavation reaction force, or a value obtained by subtracting a specified value from the maximum value of the excavation reaction force. Also, the target value can be the maximum value of the horizontal component of the excavation reaction force or the maximum value of the vertical component of the excavation reaction force. Moreover, the target value can be a value calculated based on the change in the excavation reaction force calculated and recorded during the execution of the specified excavation operation. The controller 30 can determine whether the specified excavation operation is being performed based on the posture change of the excavation attachment, and when it is determined that the specified excavation operation is being performed, determine whether the calculated excavation reaction force has reached the target value.

[0090] Furthermore, the target value can be the average value of the maximum values of the excavation reaction forces in each of multiple specified excavation operations, that is, the average value of multiple maximum excavation reaction forces. Also, the target value can be the median or the mode of multiple maximum excavation reaction forces, etc.

[0091] Moreover, the target setting unit 56 can, based on deriving the correlation between the maximum value of the excavation reaction force and the excavation amount in each of one or more excavation operations, set the excavation reaction force corresponding to the desired excavation amount as the target value. At this time, the desired excavation amount such as 80% or 90% of the capacity of the bucket 6 can be a pre-set excavation amount or an excavation amount input through the input device 42. Additionally, the correlation can be stored as a calculation formula such as a linear equation or a quadratic equation, or can be stored as a reference table.

[0092] The excavation control unit 57 is configured to control (support) the excavation operation performed by the operator of the excavator 100. In the illustrated example, the excavation control unit 57 is configured to support each excavation operation after the target value is set by the target setting unit 56. Specifically, when the value of the excavation reaction force repeatedly calculated during the excavation operation reaches the target value, the excavation control unit 57 notifies the operator of the excavator 100 of the situation where the value of the excavation reaction force has reached the target value through a notification mechanism such as the display device 40 or the sound output device 43. At this time, the operator performs a boom lifting operation to lift at least a part of the bucket 6 that is underground into the air, thereby enabling the excavation operation to end in a state where the bucket 6 is filled with sand.

[0093] When the excavation reaction force reaches the target value, the excavation control unit 57 can automatically operate one or more actuators. Automatically operating the actuator means operating the actuator regardless of the operation of the operation device 26. In the illustrated example, the actuator is at least one of the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9. In the illustrated example, when the excavation reaction force reaches the target value, the excavation control unit 57 automatically extends the boom cylinder 7 to raise the boom 4 and lift at least a part of the bucket 6 underground into the air, so that the excavation operation can be ended with the bucket 6 filled with sand and soil. Further, when the excavation reaction force reaches the target value, even when the operator operates the operation device 26, the excavation control unit 57 can stop the excavation operation of the excavation attachment. After stopping the excavation operation, the operator performs a boom raising operation to raise the boom 4 and lift at least a part of the bucket 6 underground into the air, so that the excavation operation can be ended with the bucket 6 filled with sand and soil.

[0094] The excavation control unit 57 may also be configured to support the excavation operation performed by the operator of the excavator 100 even when the value of the excavation reaction force repeatedly calculated during the excavation operation does not reach the target value after the target value is set by the target setting unit 56. For example, the excavation control unit 57 can automatically operate one or more actuators in such a way that the working part (the tip of the bucket 6) of the terminal attachment moves linearly until the value of the excavation reaction force reaches the target value. Specifically, the excavation control unit 57 can automatically operate at least one of the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 in such a way that the tip of the bucket 6 moves linearly along the ground surface, the horizontal plane, or the target construction surface. At this time, the operator of the excavator 100 can, for example, only perform an arm retraction operation to move the tip of the bucket 6 underground linearly along the ground surface, the horizontal plane, or the target construction surface until the value of the excavation reaction force reaches the target value, and when the value of the excavation reaction force reaches the target value, lift at least a part of the bucket 6 underground into the air, so that the excavation operation can be ended with the bucket 6 filled with sand and soil. This structure is effective, for example, when excavating a trench of a certain depth.

[0095] Next, refer to Figure 3 the hydraulic system of the excavator 100 will be described. Figure 3 is a diagram schematically showing a structural example of the hydraulic system of the excavator 100. In addition, similar to the case of Figure 2 etc., in Figure 3 the mechanical power transmission pipeline, the working oil pipeline, the pilot pipeline, and the electrical signal pipeline are represented by double lines, solid lines, dotted lines, and dashed lines, respectively.

[0096] The hydraulic system circulates the working oil from the left main pump 14L driven by the engine 11 through the left intermediate bypass oil passage C1L and the left parallel oil passage C2L to the working oil tank, and circulates the working oil from the right main pump 14R driven by the engine 11 through the right intermediate bypass oil passage C1R and the right parallel oil passage C2R to the working oil tank.

[0097] The left intermediate bypass oil passage C1L starts from the left main pump 14L and sequentially passes through the control valves 171, 173, 175L, and 176L arranged in the control valve unit 17, and reaches the working oil tank.

[0098] The right intermediate bypass oil passage C1R starts from the right main pump 14R and sequentially passes through the control valves 172, 174, 175R, and 176R arranged in the control valve unit 17, and reaches the working oil tank.

[0099] The control valve 171 is a spool valve that supplies the working oil discharged from the left main pump 14L to the left travel hydraulic motor 2ML and discharges the working oil discharged from the left travel hydraulic motor 2ML to the working oil tank.

[0100] The control valve 172 is a spool valve that supplies the working oil discharged from the right main pump 14R to the right travel hydraulic motor 2MR and discharges the working oil discharged from the right travel hydraulic motor 2MR to the working oil tank.

[0101] The control valve 173 is a spool valve that supplies the working oil discharged from the left main pump 14L to the swing hydraulic motor 2A and discharges the working oil discharged from the swing hydraulic motor 2A to the working oil tank.

[0102] The control valve 174 is a spool valve that supplies the working oil discharged from the right main pump 14R to the bucket cylinder 9 and discharges the working oil in the bucket cylinder 9 to the working oil tank.

[0103] The control valve 175 includes the control valve 175L and the control valve 175R. The control valve 175L is a spool valve that supplies the working oil discharged from the left main pump 14L to the boom cylinder 7 and discharges the working oil in the boom cylinder 7 to the working oil tank. The control valve 175R is a spool valve that supplies the working oil discharged from the right main pump 14R to the boom cylinder 7 and discharges the working oil in the boom cylinder 7 to the working oil tank.

[0104] The control valve 176 includes the control valve 176L and the control valve 176R. The control valve 176L is a spool valve that supplies the working oil discharged from the left main pump 14L to the arm cylinder 8 and discharges the working oil in the arm cylinder 8 to the working oil tank. The control valve 176R is a spool valve that supplies the working oil discharged from the right main pump 14R to the arm cylinder 8 and discharges the working oil in the arm cylinder 8 to the working oil tank.

[0105] The control valves 171 to 176 respectively adjust the flow rate of the working oil supplied to the hydraulic actuator or switch the flow direction according to the pilot pressure acting on the pilot ports.

[0106] The left parallel oil passage C2L is arranged in parallel with the left intermediate bypass oil passage C1L and is configured to be able to supply the working oil discharged from the left main pump 14L to the control valves 173, the control valve 175L, and the control valve 176L respectively. Thus, when the flow of the working oil through the left intermediate bypass oil passage C1L is restricted or cut off by one of the control valves 171, the control valve 173, or the control valve 175L, the left parallel oil passage C2L can supply the working oil to a more downstream control valve.

[0107] The right parallel oil passage C2R is arranged in parallel with the right intermediate bypass oil passage C1R and is configured to be able to supply the working oil discharged from the right main pump 14R to the control valves 174, the control valve 175R, and the control valve 176R respectively. Thus, when the flow of the working oil through the right intermediate bypass oil passage C1R is restricted or cut off by one of the control valves 172, the control valve 174, or the control valve 175R, the right parallel oil passage C2R can supply the working oil to a more downstream control valve.

[0108] The left regulator 13L is configured to be able to adjust the discharge amount of the left main pump 14L by adjusting the deflection angle of the swash plate of the left main pump 14L under the control of the controller 30. The right regulator 13R is configured to be able to adjust the discharge amount of the right main pump 14R by adjusting the deflection angle of the swash plate of the right main pump 14R under the control of the controller 30.

[0109] The left discharge pressure sensor 28L detects the discharge pressure of the left main pump 14L, and a detection signal corresponding to the detected discharge pressure is input to the controller 30. The same applies to the right discharge pressure sensor 28R. Thus, the controller 30 can control the left regulator 13L according to the discharge pressure of the left main pump 14L and can control the right regulator 13R according to the discharge pressure of the right main pump 14R.

[0110] In the left intermediate bypass oil passage C1L, a left throttle 18L is provided between each control valve 176L located at the most downstream and the working oil tank. Thus, the flow of the working oil discharged from the left main pump 14L is restricted by the left throttle 18L. And the left throttle 18L generates a left control pressure for controlling the left regulator 13L. In the right intermediate bypass oil passage C1R, a right throttle 18R is provided between each control valve 176R located at the most downstream and the working oil tank. Thus, the flow of the working oil discharged from the right main pump 14R is restricted by the right throttle 18R. And the right throttle 18R generates a right control pressure for controlling the right regulator 13R.

[0111] The left control pressure sensor 19L detects the left control pressure, and a detection signal corresponding to the detected left control pressure is input to the controller 30. The right control pressure sensor 19R detects the right control pressure, and a detection signal corresponding to the detected right control pressure is input to the controller 30.

[0112] The controller 30 can control the left regulator 13L according to the discharge pressure of the left main pump 14L detected by the left discharge pressure sensor 28L, and adjust the discharge amount of the left main pump 14L. For example, the controller 30 can control the left regulator 13L according to an increase in the discharge pressure of the left main pump 14L, and adjust the swash plate deflection angle of the left main pump 14L, thereby reducing the discharge amount of the left main pump 14L. The same applies to the right regulator 13R. Thus, the controller 30 can perform total horsepower control of the main pump 14 so that the absorbed horsepower of the main pump 14 represented by the product of the discharge pressure and the discharge amount does not exceed the output horsepower of the engine 11.

[0113] Moreover, the controller 30 can control the left regulator 13L according to the left control pressure detected by the left control pressure sensor 19L, thereby adjusting the discharge amount of the left main pump 14L. For example, for the controller 30, the greater the left control pressure, the smaller the discharge amount of the left main pump 14L, and the smaller the left control pressure, the greater the discharge amount of the left main pump 14L. The same applies to the discharge amount of the right main pump 14R.

[0114] Specifically, in the standby state ( Figure 3 the state shown) in which none of the hydraulic actuators in the excavator 100 are operated, the working oil discharged from the left main pump 14L reaches the left throttle 18L through the left intermediate bypass oil passage C1L. And the flow of the working oil discharged from the left main pump 14L increases the left control pressure generated upstream of the left throttle 18L. As a result, the controller 30 reduces the discharge amount of the left main pump 14L to the allowable minimum discharge amount, thereby suppressing the pressure loss (pumping loss) when the working oil discharged from the left main pump 14L passes through the left intermediate bypass oil passage C1L. The same applies to the pressure loss (pumping loss) when the working oil discharged from the right main pump 14R passes through the right intermediate bypass oil passage C1R.

[0115] On the other hand, when a certain hydraulic actuator is operated by the operating device 26, the working oil discharged from the left main pump 14L flows into the hydraulic actuator to be operated via the control valve corresponding to the hydraulic actuator to be operated. And the flow of the working oil discharged from the left main pump 14L reduces or eliminates the amount reaching the left throttle 18L, thereby reducing the left control pressure generated upstream of the left throttle 18L. As a result, the controller 30 can increase the discharge amount of the left main pump 14L, circulate sufficient working oil in the hydraulic actuator to be operated, and reliably drive the hydraulic actuator to be operated. The same applies to the working oil discharged from the right main pump 14R.

[0116] Next, referring to Figures 4A - 4F , the structure of the controller 30 for actuating the actuator will be described. Figures 4A - 4F is a diagram showing a part of the hydraulic system extracted. Specifically, Figure 4A is a diagram showing the part of the hydraulic system related to the operation of the arm cylinder 8 extracted, Figure 4B is a diagram showing the part of the hydraulic system related to the operation of the boom cylinder 7 extracted. Figure 4C is a diagram showing the part of the hydraulic system related to the operation of the bucket cylinder 9 extracted, Figure 4D is a diagram showing the part of the hydraulic system related to the operation of the swing hydraulic motor 2A extracted. Figure 4E is a diagram showing the part of the hydraulic system related to the operation of the left travel hydraulic motor 2ML extracted, Figure 4F is a diagram showing the part of the hydraulic system related to the operation of the right travel hydraulic motor 2MR extracted.

[0117] As Figures 4A - 4F shown, the hydraulic system includes a solenoid valve 31. The solenoid valve 31 includes solenoid valves 31AL to 31FL and solenoid valves 31AR to 31FR.

[0118] The solenoid valve 31 is arranged in the pipeline connecting the pilot pump 15 and the pilot port of the corresponding control valve in the control valve unit 17, and is configured to be able to change the flow path area of the pipeline by changing the opening area. In the present embodiment, the solenoid valve 31 is an electromagnetic proportional valve and operates according to the control command output by the controller 30. Therefore, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the pilot port of the corresponding control valve in the control valve unit 17 via the solenoid valve 31, either according to the operation of the operator on the operating device 26 or independently of the operation of the operator on the operating device 26. And the controller 30 can make the pilot pressure generated by the solenoid valve 31 act on the pilot port of the corresponding control valve.

[0119] According to this structure, the controller 30 can actuate the hydraulic actuator corresponding to the specific operating device 26 even when not operating the specific operating device 26, except when operating a specific operating device 26. And even when operating a specific operating device 26, the controller 30 can forcibly stop the operation of the hydraulic actuator corresponding to the specific operating device 26.

[0120] For example, as Figure 4AAs shown, the left joystick 26L is used to operate the arm 5. Specifically, the left joystick 26L uses the pilot oil discharged from the pilot pump 15 to apply a pilot pressure corresponding to the operation in the front-rear direction to the pilot ports of the control valve 176. More specifically, when the left joystick 26L is operated in the arm retraction direction (rear direction), a pilot pressure corresponding to the operation amount is applied to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R. And when the left joystick 26L is operated in the arm opening direction (front direction), a pilot pressure corresponding to the operation amount is applied to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R.

[0121] A switch SW is provided on the operating device 26. In the present embodiment, the switch SW includes a switch SW1 and a switch SW2. The switch SW1 is an MC switch (push-button switch) provided at the front end of the left joystick 26L. The operator can operate the left joystick 26L while pressing the switch SW1. The switch SW1 can be provided on the right joystick 26R or at other positions within the cab 10. The switch SW2 is an MC switch (push-button switch) provided at the front end of the left travel lever 26DL. The operator can operate the left travel lever 26DL while pressing the switch SW2. The switch SW2 can be provided on the right travel lever 26DR or at other positions within the cab 10.

[0122] The operation sensor 29LA detects the operation content of the left joystick 26L by the operator in the front-rear direction and outputs the detected value to the controller 30.

[0123] The solenoid valve 31AL operates according to the control command (current command) output from the controller 30. And it adjusts the pilot pressure generated by the pilot oil introduced from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R through the solenoid valve 31AL. The solenoid valve 31AR operates according to the control command (current command) output from the controller 30. And it adjusts the pilot pressure generated by the pilot oil introduced from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R through the solenoid valve 31AR. The solenoid valve 31AL can adjust the pilot pressure in such a way that the control valves 176L and 176R can be stopped at any valve positions. Similarly, the solenoid valve 31AR can adjust the pilot pressure in such a way that the control valves 176L and 176R can be stopped at any valve positions.

[0124] According to this structure, based on the boom retraction operation performed by the operator, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the solenoid valve 31AL. Also, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the solenoid valve 31AL regardless of the boom retraction operation performed by the operator. That is, the controller 30 can retract the boom 5 based on the boom retraction operation performed by the operator or regardless of the boom retraction operation performed by the operator. Thus, the solenoid valve 31AL functions as a "boom solenoid valve" or a "boom retraction solenoid valve".

[0125] Also, based on the boom extension operation performed by the operator, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the solenoid valve 31AR. Also, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the solenoid valve 31AR regardless of the boom extension operation performed by the operator. That is, the controller 30 can extend the boom 5 based on the boom extension operation performed by the operator or regardless of the boom extension operation performed by the operator. Thus, the solenoid valve 31AR functions as a "boom solenoid valve" or a "boom extension solenoid valve".

[0126] Also, with this structure, even when the operator is performing a boom retraction operation, the controller 30 can, as needed, reduce the pilot pressure acting on the closing-side pilot ports of the control valve 176 (the left pilot port of the control valve 176L and the right pilot port of the control valve 176R) to forcibly stop the retraction action of the boom 5. The same applies to the case of forcibly stopping the extension action of the boom 5 when the operator performs a boom extension operation.

[0127] Alternatively, even when the operator is performing a boom retraction operation, the controller 30 can, as needed, control the solenoid valve 31AR to increase the pilot pressure acting on the opening-side pilot ports of the control valve 176 (the right pilot port of the control valve 176L and the left pilot port of the control valve 176R) located on the side opposite to the closing-side pilot ports of the control valve 176, to forcibly return the control valve 176 to the neutral position, thereby forcibly stopping the retraction action of the boom 5. The same applies to the case of forcibly stopping the extension action of the boom 5 when the operator performs a boom extension operation.

[0128] And, omitting reference to the following Figures 4B - 4FThe same applies to the cases where the movement of the boom 4 is forcibly stopped when the operator performs a boom raising operation or a boom lowering operation, the movement of the bucket 6 is forcibly stopped when the operator performs a bucket retracting operation or a bucket opening operation, and the rotational movement of the upper slewing body 3 is forcibly stopped when the operator performs a slewing operation. Also, the same applies to the case where the traveling movement of the lower traveling body 1 is forcibly stopped when the operator performs a traveling operation.

[0129] Further, the controller 30 may also be configured such that, in order to improve the responsiveness of the stick operation (stick retracting operation and stick opening operation), a minute pilot pressure is applied to the pilot ports on both sides of the control valve 176 before the stick operation is performed. The same applies to other operations such as the boom operation (boom raising operation and boom lowering operation). That is, the controller 30 can improve the responsiveness of the hydraulic actuator by using more pilot oil.

[0130] And, as Figure 4B shown, the right operation lever 26R is used to operate the boom 4. Specifically, the right operation lever 26R uses the pilot oil discharged from the pilot pump 15 to apply a pilot pressure corresponding to the operation in the front-rear direction to the pilot port of the control valve 175. More specifically, when the operation is performed in the boom raising direction (rear direction), the right operation lever 26R applies a pilot pressure corresponding to the operation amount to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R. And, when the operation is performed in the boom lowering direction (front direction), the right operation lever 26R applies a pilot pressure corresponding to the operation amount to the right pilot port of the control valve 175R.

[0131] The operation sensor 29RA detects the operation content of the right operation lever 26R by the operator in the front-rear direction and outputs the detected value to the controller 30.

[0132] The solenoid valve 31BL operates according to the control command (current command) output from the controller 30. And, it adjusts the pilot pressure generated by the pilot oil introduced from the pilot pump 15 to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R. The solenoid valve 31BR operates according to the control command (current command) output from the controller 30. And, it adjusts the pilot pressure generated by the pilot oil introduced from the pilot pump 15 to the right pilot port of the control valve 175R. The solenoid valve 31BL can adjust the pilot pressure in such a manner that the control valve 175L and the control valve 175R can be stopped at any valve position. And, the solenoid valve 31BR can adjust the pilot pressure in such a manner that the control valve 175R can be stopped at any valve position.

[0133] According to this structure, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the solenoid valve 31BL according to the boom lifting operation performed by the operator. Also, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the solenoid valve 31BL regardless of the boom lifting operation performed by the operator. That is, the controller 30 can lift the boom 4 according to the boom lifting operation performed by the operator or regardless of the boom lifting operation performed by the operator. Thus, the solenoid valve 31BL functions as a "boom solenoid valve" or a "boom lifting solenoid valve".

[0134] Also, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 175R via the solenoid valve 31BR according to the boom lowering operation performed by the operator. Also, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 175R via the solenoid valve 31BR regardless of the boom lowering operation performed by the operator. That is, the controller 30 can lower the boom 4 according to the boom lowering operation performed by the operator or regardless of the boom lowering operation performed by the operator. Thus, the solenoid valve 31BR functions as a "boom solenoid valve" or a "boom lowering solenoid valve".

[0135] Also, as Figure 4C shown, the right operation lever 26R is used to operate the bucket 6. Specifically, the right operation lever 26R causes a pilot pressure corresponding to the operation in the left-right direction to act on the pilot port of the control valve 174 by using the pilot oil discharged from the pilot pump 15. More specifically, when an operation is performed in the bucket retracting direction (left direction), the right operation lever 26R causes a pilot pressure corresponding to the operation amount to act on the left pilot port of the control valve 174. Also, when an operation is performed in the bucket opening direction (right direction), the right operation lever 26R causes a pilot pressure corresponding to the operation amount to act on the right pilot port of the control valve 174.

[0136] The operation sensor 29RB detects the operation content of the right operation lever 26R by the operator in the left-right direction and outputs the detected value to the controller 30. Also, when the bucket angle sensor S3 is omitted, the controller 30 can estimate the bucket angle based on the output of the operation sensor 29RB.

[0137] The solenoid valve 31CL operates according to the control command (current command) output by the controller 30. Moreover, the pilot pressure generated by the pilot oil introduced from the pilot pump 15 into the left pilot port of the control valve 174 via the solenoid valve 31CL is adjusted. The solenoid valve 31CR operates according to the control command (current command) output by the controller 30. Moreover, the pilot pressure generated by the pilot oil introduced from the pilot pump 15 into the right pilot port of the control valve 174 via the solenoid valve 31CR is adjusted. The solenoid valve 31CL can adjust the pilot pressure in such a manner that the control valve 174 can be stopped at an arbitrary valve position. Similarly, the solenoid valve 31CR can adjust the pilot pressure in such a manner that the control valve 174 can be stopped at an arbitrary valve position.

[0138] According to this configuration, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 174 via the solenoid valve 31CL according to the bucket retraction operation performed by the operator. Moreover, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 174 via the solenoid valve 31CL regardless of the bucket retraction operation performed by the operator. That is, the controller 30 can retract the bucket 6 according to the bucket retraction operation performed by the operator or regardless of the bucket retraction operation performed by the operator. Thus, the solenoid valve 31CL functions as a "bucket solenoid valve" or a "bucket retraction solenoid valve".

[0139] Moreover, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 174 via the solenoid valve 31CR according to the bucket opening operation performed by the operator. Moreover, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 174 via the solenoid valve 31CR regardless of the bucket opening operation performed by the operator. That is, the controller 30 can open the bucket 6 according to the bucket opening operation performed by the operator or regardless of the bucket opening operation performed by the operator. Thus, the solenoid valve 31CR functions as a "bucket solenoid valve" or a "bucket opening solenoid valve".

[0140] Moreover, as Figure 4D shown, the left operation lever 26L is also used to operate the slewing mechanism 2. Specifically, the left operation lever 26L causes the pilot pressure corresponding to the operation in the left-right direction to act on the pilot port of the control valve 173 by using the pilot oil discharged from the pilot pump 15. More specifically, when the operation is performed in the left slewing direction (left direction), the left operation lever 26L causes the pilot pressure corresponding to the operation amount to act on the left pilot port of the control valve 173. Moreover, when the operation is performed in the right slewing direction (right direction), the left operation lever 26L causes the pilot pressure corresponding to the operation amount to act on the right pilot port of the control valve 173.

[0141] The operation sensor 29LB detects the operation content of the left operation lever 26L by the operator in the left-right direction, and outputs the detected value to the controller 30.

[0142] The solenoid valve 31DL operates according to the control command (current command) output from the controller 30. Moreover, the pilot pressure generated by the pilot oil introduced from the pilot pump 15 into the left pilot port of the control valve 173 via the solenoid valve 31DL can be adjusted. The solenoid valve 31DR operates according to the control command (current command) output from the controller 30. Moreover, the pilot pressure generated by the pilot oil introduced from the pilot pump 15 into the right pilot port of the control valve 173 via the solenoid valve 31DR is adjusted. The solenoid valve 31DL can adjust the pilot pressure in such a manner that the control valve 173 can be stopped at an arbitrary valve position. Similarly, the solenoid valve 31DR can adjust the pilot pressure in such a manner that the control valve 173 can be stopped at an arbitrary valve position.

[0143] According to this configuration, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 173 via the solenoid valve 31DL according to the left turning operation performed by the operator. Moreover, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 173 regardless of the left turning operation performed by the operator. That is, the controller 30 can cause the slewing mechanism 2 to perform left turning according to the left turning operation performed by the operator or regardless of the left turning operation performed by the operator. Thus, the solenoid valve 31DL functions as a "slewing solenoid valve" or a "left turning solenoid valve".

[0144] Moreover, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 173 via the solenoid valve 31DR according to the right turning operation performed by the operator. Moreover, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 173 regardless of the right turning operation performed by the operator. That is, the controller 30 can cause the slewing mechanism 2 to perform right turning according to the right turning operation performed by the operator or regardless of the right turning operation performed by the operator. Thus, the solenoid valve 31DR functions as a "slewing solenoid valve" or a "right turning solenoid valve".

[0145] Moreover, as Figure 4EAs shown, the left travel lever 26DL is used to operate the left crawler 1CL. Specifically, the left travel lever 26DL uses the pilot oil discharged from the pilot pump 15 to apply a pilot pressure corresponding to the operation in the front-rear direction to the pilot port of the control valve 171. More specifically, when the operation is performed in the forward direction (front direction), the left travel lever 26DL applies a pilot pressure corresponding to the operation amount to the left pilot port of the control valve 171. And when the operation is performed in the backward direction (rear direction), the left travel lever 26DL applies a pilot pressure corresponding to the operation amount to the right pilot port of the control valve 171.

[0146] The operation sensor 29DL electrically detects the operation content of the left travel lever 26DL by the operator in the front-rear direction and outputs the detected value to the controller 30.

[0147] The solenoid valve 31EL operates according to the current command output by the controller 30. And the solenoid valve 31EL adjusts the pilot pressure generated by the pilot oil introduced from the pilot pump 15 into the left pilot port of the control valve 171 via the solenoid valve 31EL. The solenoid valve 31ER operates according to the current command output by the controller 30. And the solenoid valve 31ER adjusts the pilot pressure generated by the pilot oil introduced from the pilot pump 15 into the right pilot port of the control valve 171 via the solenoid valve 31ER. The solenoid valves 31EL and 31ER can adjust the pilot pressure in such a way that the control valve 171 can be stopped at any valve position.

[0148] With this structure, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 171 via the solenoid valve 31EL regardless of the left forward operation performed by the operator. That is, the left crawler 1CL can be made to move forward. And the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 171 via the solenoid valve 31ER regardless of the left backward operation performed by the operator. That is, the left crawler 1CL can be made to move backward. Thus, the solenoid valve 31EL functions as a "left travel solenoid valve" or "left forward solenoid valve", and the solenoid valve 31ER functions as a "left travel solenoid valve" or "left backward solenoid valve".

[0149] And, as Figure 4FAs shown, the right travel lever 26DR is used to operate the right crawler 1CR. Specifically, the right travel lever 26DR uses the pilot oil discharged from the pilot pump 15 to apply a pilot pressure corresponding to the operation in the forward and backward directions to the pilot port of the control valve 172. More specifically, when the operation is performed in the forward direction (front direction), the right travel lever 26DR applies a pilot pressure corresponding to the operation amount to the right pilot port of the control valve 172. And when the operation is performed in the backward direction (rear direction), the right travel lever 26DR applies a pilot pressure corresponding to the operation amount to the left pilot port of the control valve 172.

[0150] The operation sensor 29DR electrically detects the operation content of the right travel lever 26DR by the operator in the forward and backward directions and outputs the detected value to the controller 30.

[0151] The solenoid valve 31FL operates according to the current command output by the controller 30. And the solenoid valve 31FL adjusts the pilot pressure generated by the pilot oil introduced from the pilot pump 15 into the left pilot port of the control valve 172 via the solenoid valve 31FL. The solenoid valve 31FR operates according to the current command output by the controller 30. And the solenoid valve 31FR adjusts the pilot pressure generated by the pilot oil introduced from the pilot pump 15 into the right pilot port of the control valve 172 via the solenoid valve 31FR. The solenoid valves 31FL and 31FR can adjust the pilot pressure in such a way that the control valve 172 can be stopped at any valve position.

[0152] With this structure, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 172 via the solenoid valve 31FL regardless of the right forward operation performed by the operator. That is, the right crawler 1CR can be made to move forward. And the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 172 via the solenoid valve 31FR regardless of the right backward operation performed by the operator. That is, the right crawler 1CR can be made to move backward. Thus, the solenoid valve 31FL functions as a "right travel solenoid valve" or a "right forward solenoid valve", and the solenoid valve 31FR functions as a "right travel solenoid valve" or a "right backward solenoid valve".

[0153] And the excavator 100 may be provided with a structure that automatically operates the bucket tilt mechanism. At this time, the hydraulic system part related to the bucket tilt cylinder constituting the bucket tilt mechanism may be configured to be the same as the hydraulic system part related to the operation of the boom cylinder 7 and the like.

[0154] In addition, a description is given regarding an electric operating lever as a mode of the operating device 26. However, a hydraulic operating lever may be employed instead of the electric operating lever. In this case, the operation amount of the hydraulic operating lever can also be detected by a pressure sensor in the form of pressure and input to the controller 30. Moreover, a solenoid valve may be disposed between the operating device 26, which is a hydraulic operating lever, and the pilot ports of the respective control valves. The solenoid valve is configured to operate according to an electric signal from the controller 30. According to this configuration, if a manual operation using the operating device 26, which is a hydraulic operating lever, is performed, the operating device 26 increases or decreases the pilot pressure according to the operation amount, thereby enabling the respective control valves to move. Further, the respective control valves may be constituted by electromagnetic slide valves. In this case, the electromagnetic slide valves operate according to an electric signal from the controller 30 corresponding to the operation amount of the electric operating lever.

[0155] Next, with reference to Figure 5 , the process of the loading operation performed by the excavator 100 will be described. Figure 5 FIG. is a diagram for explaining the process of the loading operation performed by the excavator 100.

[0156] Figure 5 (A) to Figure 5 (D) of FIG. show a state in which a digging operation is being performed. In addition, the period during which the digging operation is performed is referred to as the digging operation period. Further, the digging operation is divided into Figure 5 (A) of FIG. and Figure 5 (B) of FIG., which show the first half of the digging operation, and Figure 5 (C) of FIG. and Figure 5 (D) of FIG., which show the second half of the digging operation.

[0157] As shown in Figure 5 (A) of FIG., the operator of the excavator 100 moves the front end of the bucket 6 so that the front end of the bucket 6 is at a desired height position relative to the object to be dug (sand in this example), and retracts the arm 5 from the state where the arm 5 is extended as shown in Figure 5 (A) of FIG. until the arm 5 is substantially perpendicular to the ground as shown in Figure 5 (B) of FIG. By this operation, sand at a certain depth is dug and piled up until the arm 5 is substantially perpendicular to the ground surface. The above operation is referred to as the first half of the digging operation, and this period is referred to as the first half period of the digging operation.

[0158] Then, as shown in Figure 5 (C) of FIG., the operator further retracts the arm 5, thereby further piling up the sand by the bucket 6. And, as shown in Figure 5 (D) of FIG., the operator retracts the bucket 6 until the upper edge becomes substantially horizontal, and takes in the sand piled up together into the bucket 6. Further, the operator raises the boom 4 and raises the bucket 6 toFigure 5 The position shown in (D) above. The above actions are called the latter half of the digging action, and this period is called the latter half period of the digging action. Figure 5 The action of (C) can be a combined action of the arm 5 and the bucket 6, or a combined action of the boom 4, the arm 5 and the bucket 6.

[0159] Next, the operator, while making the upper edge of the bucket 6 become substantially horizontal, as Figure 5 shown in (E), raises the boom 4 until the bottom of the bucket 6 reaches a desired height from the ground. The desired height is, for example, a height above the height of the rear gate of the dump truck. The operator rotates the upper slewing body 3 as indicated by the arrow after or simultaneously with this action, so that the bucket 6 is moved to the position for unloading (tipping).

[0160] If the operator completes the boom raising and slewing action, as Figure 5 shown in (F), the arm 5 and the bucket 6 are opened to unload (tip) the soil in the bucket 6 onto the carriage of the dump truck or the ground, etc. In this unloading action (tipping action), the operator can unload by only opening the bucket 6, or can unload while lowering the boom 4 and opening the arm 5 and the bucket 6.

[0161] If the tipping action is completed, as Figure 5 shown in (G), the operator rotates the upper slewing body 3 as indicated by the arrow, so that the bucket 6 is moved directly above the digging position. Then, as Figure 5 shown in (A), the operator lowers the bucket 6 to the desired height and resumes the digging action. In addition, the operator can lower the boom 4 while rotating to lower the bucket 6 to a position at the desired height from the object to be dug.

[0162] In this way, while the controller 30 repeatedly performs the cycle composed of "the first half of the digging action", "the latter half of the digging action", "the boom raising and slewing action", "the tipping action" and "the boom lowering and slewing action", the loading operation performed by the excavator 100 is carried out.

[0163] Next, with reference to Figure 6 , an example of the process of setting the target value for the controller 30 (hereinafter referred to as "the setting process".) will be described. Figure 6 is a flowchart showing an example of the process of the setting process. In the illustrated example, the target setting unit 56 of the controller 30 executes this setting process every time the digging action is completed until the target value is set. Specifically, the target setting unit 56 determines whether the digging action is completed based on the outputs of the posture sensor, the cylinder pressure sensor, etc. And when the target setting unit 56 determines that the digging action is completed, it executes this setting process.

[0164] First, the target setting unit 56 determines whether a specified excavation operation has been performed (step ST1). In the illustrated example, based on the image of the bucket 6 lifted into the air after the excavation operation captured by the camera S6F, the target setting unit 56 determines whether the amount of sand and soil taken into the bucket 6 is more than the specified amount. And when the target setting unit 56 can determine that the amount of sand and soil taken into the bucket 6 is more than the specified amount, it determines that the specified excavation operation has been performed. For example, when the target setting unit 56 can determine that the bucket 6 is filled with sand and soil, it determines that the specified excavation operation has been performed. On the other hand, when the target setting unit 56 cannot determine that the amount of sand and soil taken into the bucket 6 is more than the specified amount, that is, when it can be determined that the bucket 6 is not filled with sand and soil, it determines that the specified excavation operation has not been performed. In addition, for the target setting unit 56, even when it can be determined that the bucket 6 is filled with sand and soil, if it is determined that the amount of sand and soil spilled from the bucket 6 when the bucket 6 is lifted is more than the specified amount, it can also be determined that the specified excavation operation has not been performed. In addition, the amount of sand and soil spilled from the bucket 6 can be the weight of the sand and soil spilled from the bucket 6 or the volume of the sand and soil spilled from the bucket 6. The weight of the sand and soil can be calculated, for example, based on the output of the posture sensor and the output of the cylinder pressure sensor. And the volume of the sand and soil can be calculated, for example, based on the image of the bucket 6 in the air captured by the camera S6F.

[0165] Moreover, the target setting unit 56 can determine that the specified excavation operation has been performed when a specified button is pressed. The specified button is a button pressed by the operator when the operator observes the inside of the bucket 6 lifted into the air after the excavation operation with the naked eye and determines that the bucket 6 is filled with sand and soil. In addition, the operator can also observe the image captured by the camera S6F to determine whether the bucket 6 is filled with sand and soil. At this time, the image captured by the camera S6F can be displayed on the display device 40.

[0166] And in the case where it is determined that the specified excavation operation has not been performed (the "no" in step ST1), the target setting unit 56 does not set a target value and ends the current setting process.

[0167] On the other hand, in the case where it is determined that the specified excavation operation has been performed (the "yes" in step ST1), the target setting unit 56 sets a target value (step ST2). In the illustrated example, the target setting unit 56 sets the maximum value of the excavation reaction force calculated during the execution of the excavation operation determined to be the specified excavation operation as the target value. In addition, the target setting unit 56 can set the maximum value of the horizontal component or the vertical component of the excavation reaction force calculated during the execution of the excavation operation determined to be the specified excavation operation as the target value. At this time, this target value is used to compare with the horizontal component or the vertical component of the excavation reaction force calculated during the subsequent excavation operation.

[0168] Next, referring to Figure 7 , an example of the process of the controller 30 supporting the excavation operation (hereinafter referred to as "support process") will be described. Figure 7 FIG. is a flowchart showing an example of the process of the support process. In the illustrated example, during the excavation operation, the excavation control unit 57 of the controller 30 repeatedly executes this support process at a predetermined control cycle. Specifically, the excavation control unit 57 determines whether an excavation operation has been performed based on the outputs of the posture sensor, the cylinder pressure sensor, etc. More specifically, the excavation control unit 57 determines that the excavation operation has started when the excavation reaction force repeatedly calculated by the excavation reaction force calculation unit 55 at a predetermined control cycle exceeds a predetermined start determination value. And, after the excavation control unit 57 determines that the excavation operation has started, when the excavation reaction force repeatedly calculated by the excavation reaction force calculation unit 55 at a predetermined control cycle is lower than a predetermined end determination value, the excavation control unit 57 determines that the excavation operation has ended. The start determination value and the end determination value are respectively values determined according to the posture of the attachment. And, the excavation control unit 57 repeatedly executes this support process during the period from when it is determined that the excavation operation has started to when it is determined that the excavation operation has ended. In addition, the excavation control unit 57 may make various determinations based on the magnitude of the horizontal component or the vertical component of the excavation reaction force repeatedly calculated by the excavation reaction force calculation unit 55 at a predetermined control cycle. At this time, the start determination value and the end determination value are respectively values corresponding to the magnitude of the horizontal component or the vertical component of the excavation reaction force.

[0169] First, the excavation control unit 57 determines whether the excavation reaction force has reached the target value (step ST11). In the illustrated example, the excavation control unit 57 determines whether the excavation reaction force calculated by the excavation reaction force calculation unit 55 has reached the target value set by the target setting unit 56. When the target setting unit 56 has not set the target value, that is, when the target value maintains the initial value (the maximum value that the excavation reaction force can take), the excavation control unit 57 determines that the excavation reaction force has not reached the target value. And, the excavation control unit 57 may be configured not to execute the support process before setting the target value.

[0170] When it is determined that the excavation reaction force has reached the target value (Yes in step ST11), the excavation control unit 57 executes the excavation assistance function (step ST12). In the illustrated example, the excavation assistance function is a function of notifying the operator of the excavator 100 that the excavation reaction force has reached the target value. Specifically, the excavation control unit 57 outputs a control command to the display device 40 to cause the display device 40 to display image information notifying that the excavation reaction force has reached the target value, or outputs a control command to the sound output device 43 to cause the sound output device 43 to output sound information notifying that the excavation reaction force has reached the target value. The information notifying that the excavation reaction force has reached the target value can be, for example, information indicating the start of the boom lifting operation. By receiving such information, the operator of the excavator 100 can start the boom lifting operation at an appropriate timing. As a result, the operator can, for example, achieve a state where the bucket 6 is filled with sand at the end of each excavation operation. That is, the controller 30 can achieve an appropriate excavation amount through each excavation operation, and thus can improve the working efficiency of the excavator 100 or can suppress working deviations.

[0171] On the other hand, when it is determined that the excavation reaction force has not reached the target value (No in step ST11), the excavation control unit 57 does not execute the excavation assistance function and ends the current support process.

[0172] In addition, the excavation control unit 57 may be configured to execute other excavation assistance functions when it is determined that the excavation reaction force has not reached the target value. Other excavation assistance functions are, for example, an equipment guidance function or an equipment control function. Specifically, the excavation control unit 57 may be configured to automatically operate at least one of the boom cylinder 7 and the bucket cylinder 9 in such a manner that the control point set at the tip of the bucket 6 moves horizontally upward toward the upper swing body 3 when the stick retraction operation is performed while the MC switch is pressed. According to this configuration, the operator of the excavator 100 can perform the excavation operation by horizontally moving the tip of the bucket 6 in a state where the tip of the bucket 6 has entered the desired depth so as to approach the excavator 100. And, when the operator is notified that the excavation reaction force has reached the target value, the operator performs the boom lifting operation, whereby an appropriate excavation amount can be achieved.

[0173] Next, with reference to Figure 8 , the control system SYS of the excavator will be described. Figure 8 is a diagram showing a structural example of the control system SYS of the excavator. The information acquired by the excavator 100 can be shared with a manager and operators of other excavators, etc. through the control system SYS of the excavator as shown in Figure 8 .

[0174] The control system SYS is a system for controlling the excavator 100. In the illustrated example, the control system SYS mainly consists of the excavator 100, the support device 200, and the management device 300. The excavator 100, the support device 200, and the management device 300 each have a communication device and are directly or indirectly connected to each other via a mobile phone communication network, a satellite communication network, or a short-range wireless communication network, etc. The excavator 100, the support device 200, and the management device 300 that make up the control system SYS can each be one or multiple. In Figure 8 the example of, the control system SYS includes one excavator 100, one support device 200, and one management device 300.

[0175] The support device 200, as a device for supporting the control of the excavator 100, is typically a mobile terminal device, such as a computer like a notebook PC, a tablet PC, or a smart phone carried by an operator at a construction site, etc. The support device 200 can also be a computer carried by the operator of the excavator 100. However, the support device 200 can also be a fixed terminal device.

[0176] The management device 300, as a device for managing various information, is typically a fixed terminal device, such as a server computer set up in a management center outside the construction site, etc. The management device 300 can also be a portable computer (e.g., a mobile terminal device like a notebook PC, a tablet PC, or a smart phone).

[0177] At least one of the support device 200 and the management device 300 can also be equipped with a monitor and an operation device for remote operation. At this time, the excavator 100 and at least one of the support device 200 and the management device 300 form a remote operation system of the excavator. And the operator can operate the excavator 100 using the operation device for remote operation. The operation device for remote operation is connected to the controller 30 via a communication network such as a mobile phone communication network, a satellite communication network, or a short-range wireless communication network, etc. The controller 30 can be included in the support device 200 or can be included in the management device 300. And all or part of the functions executed by the controller 30 can also be executed by the support device 200 or can be executed by the management device 300. And the excavator 100 can be an unmanned excavator. At this time, the excavator 100 operates autonomously regardless of the operation of the operation device 26 (including the operation device for remote operation).

[0178] And, in Figure 8 the example shown, the excavation control unit 57 can be provided in the support device 200 or can be provided in the management device 300.

[0179] As described above, as Figure 1As shown in the figure, the excavator 100 according to the embodiment of the present invention includes: a lower traveling body 1; an upper revolving body 3 rotatably mounted on the lower traveling body 1; an attachment device AT mounted on the upper revolving body 3; and a controller 30 as a control device that repeatedly calculates the digging reaction force based on information related to the digging operation of the work object by the attachment device AT at the work site. Further, the controller 30 is configured to set a target value based on the digging reaction force calculated during one or more digging operations, and support each subsequent digging operation based on the target value related to the digging reaction force after setting the target value related to the digging reaction force.

[0180] In addition, the one or more digging operations for setting the target value are digging operations for grasping the characteristics of the ground or the like to be dug (such as hardness, viscosity, density, or the relationship between the digging amount and the digging reaction force), and can be digging operations performed according to the manual operation of the operating device 26 by the operator, or digging operations performed while receiving support based on the equipment guidance function or the equipment control function, or digging operations automatically performed regardless of the operation of the operating device 26.

[0181] Moreover, the one or more digging operations for setting the target value can be the first digging operation for trial digging at a work site, or the first digging operation performed every day at a work site, or the digging operation performed each time the characteristics of the digging object change due to rain or the like. Therefore, the target value can be configured to be reset by the operator pressing a specified switch.

[0182] According to this structure, the controller 30 can improve the working efficiency of the excavator 100 or suppress the deviation of the operation. This is because the operator of the excavator 100 can make the digging amount achieved by each digging operation consistent with the desired digging amount. That is, the operator of the excavator 100 can, for example, achieve the state where the bucket 6 is filled with sand immediately after each digging operation.

[0183] The controller 30 may be configured to determine whether a specified digging operation suitable for calculating the target value has been performed based on information related to the digging operation of the work object by the attachment device AT at the work site, and set the target value based on the digging reaction force calculated during the digging operation determined to be the specified digging operation.

[0184] In the above example, the controller 30 determines whether the desired excavation volume has been achieved based on the image of the bucket 6 after the excavation operation captured by the camera S6F. When it can be determined that the desired excavation volume has been achieved, it is determined that a prescribed excavation operation has been performed. Further, the controller 30 sets the maximum value of the excavation reaction force calculated during the excavation operation determined to be a prescribed excavation operation as the target value.

[0185] According to this configuration, the controller 30 can support the operation by the operator of the excavator 100 so that the maximum value of the excavation reaction force during each excavation operation after setting the target value is the same as the maximum value of the excavation reaction force during the prescribed excavation operation before setting the target value. Therefore, the controller 30 can suppress excessive deviation in the excavation volume based on each excavation operation after setting the target value. As a result, the controller 30 can improve the work efficiency of the excavator 100 or can suppress the deviation of the work.

[0186] The controller 30 may be configured to notify the operator that the current excavation reaction force has reached the target value during each excavation operation after setting the target value.

[0187] According to this configuration, the operator of the excavator 100 performs a boom lifting operation when receiving the notification that the current excavation reaction force has reached the target value during each excavation operation, whereby the desired excavation volume can be achieved.

[0188] The controller 30 may be configured to automatically operate a prescribed actuator when the current excavation reaction force reaches the target value during each excavation operation after setting the target value.

[0189] According to this configuration, the operator of the excavator 100 can achieve the desired excavation volume only by performing a stick retraction operation without worrying about the timing of performing the boom lifting operation.

[0190] The controller 30 may be configured to automatically operate a prescribed actuator in a manner of linearly moving to a point set at a prescribed position of the attachment until the current excavation reaction force reaches the target value during each excavation operation after setting the target value.

[0191] According to this configuration, the operator of the excavator 100, for example, can perform a stick retraction operation while pressing the MC switch after the tip of the bucket 6 enters the desired depth, and can horizontally move the tip toward the excavator 100 to perform an excavation operation until the current excavation reaction force reaches the target value. And when the current excavation reaction force reaches the target value, the excavation assist function as described above is executed, so that the operator can achieve the desired excavation volume.

[0192] As described above, the preferred embodiments of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments, nor to the embodiments described hereinafter. Various modifications, substitutions, etc. can be applied to the above-described or hereinafter-described embodiments without departing from the scope of the present invention. Moreover, the features described separately can be combined as long as there is no technical contradiction.

[0193] For example, the excavator 100 may be a remotely operated excavator. In this case, the controller 30 may be a control device provided in a remote operation room located outside the excavator 100. Moreover, the excavator 100 may also be an autonomous excavator that does not require operation by an operator.

Claims

1. A control device for an excavator, the excavator comprising a lower traveling body, an upper rotating body rotatably mounted on the lower traveling body, and an auxiliary device mounted on the upper rotating body, wherein: repeatedly calculating the excavation reaction force based on information related to the excavation action performed by the attachment on the work object at the work site, A target value is set based on excavation reaction force calculated during one or more excavation operations, and each excavation operation performed after the target value for the excavation reaction force is set is supported based on the target value for the excavation reaction force.

2. The control device for an excavator according to claim 1, wherein: It is determined whether a predetermined excavation action suitable for calculation of the target value is performed based on information related to an excavation action performed by the attachment on a work object at a work site, and the target value is set based on an excavation reaction force calculated when the excavation action is determined to be the predetermined excavation action.

3. The control device for an excavator according to claim 1, wherein: The control device is configured to notify an operator that the current excavation reaction force has reached the target value in each excavation operation performed after the target value is set.

4. The control device for an excavator according to claim 1, wherein: The control device is configured to automatically operate a predetermined actuator when the current excavation reaction force reaches the target value in each excavation operation performed after the target value is set.

5. The control device for an excavator according to claim 1, wherein: The control device is configured to automatically operate a predetermined actuator so that a point set at a predetermined position of the attachment moves linearly in each excavation operation performed after the target value is set until the current excavation reaction force reaches the target value.

6. An excavator, comprising: The control device according to any one of claims 1 to 5; The lower walking body; The upper rotating body is rotatably mounted on the lower walking body; and The auxiliary device is installed on the upper rotating body.

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