BAGGER

Abstract

An excavator for moving an object to a predetermined location by repeating a series of operations including an excavation operation and an unloading operation, the excavator comprising: a lower traveling body; an upper swing body pivotally mounted on the lower traveling body; an attachment attached to the upper swing body; a sensor attached to the upper swing body; and a controller configured to calculate, based on output signals of the sensor, an excavation reaction force generated by the excavation operation and an excavation weight, which is a weight of an object accommodated in a bucket and moved to the predetermined location.The control device is configured to set a target value related to the excavation reaction force of a second excavation operation subsequently performed one or more times based on a relationship between the excavation reaction force calculated during a first excavation operation performed one or more times and the excavation weight.

Description

TECHNICAL FIELD

[0001] This disclosure relates to excavators. STATE OF THE ART

[0002] Conventionally, an excavator is known that calculates the weight of soil and sand loaded in a bucket lifted in the air based on the measured value of a boom ground pressure sensor (see Patent Document 1). RELATED PRIOR ART PATENT DOCUMENTS

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-165260 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] However, the excavator described above may not be able to properly calculate the weight of an object loaded in the bucket, such as soil and sand, if the detected value of the boom ground pressure sensor fluctuates due to noise generated when the bucket is lifted into the air. In this case, the excavator may not be able to accurately calculate the weight of the object being moved (loaded) from an excavation attachment to a predetermined location, such as the bed of a dump truck.

[0005] Therefore, it is desirable to be able to more accurately calculate the weight of an object being brought to a predetermined location. MEANS TO SOLVE THE PROBLEMS

[0006] An excavator according to an embodiment of the present disclosure is an excavator for moving an object to a predetermined location by repeating a series of operations including an excavation operation and an unloading operation, and is provided with a lower traveling body, an upper swing body pivotally mounted on the lower traveling body, a boss attached to the upper swing body, a sensor attached to the upper swing body, and a control device configured to calculate, based on an output of the sensor, an excavation reaction force generated by the excavation operation and an excavation weight, which is the weight of the object accommodated in a bucket and moved to the predetermined location.which is subsequently carried out one or more times based on a relationship between the excavation reaction force calculated during a first excavation operation carried out one or more times and the excavated weight. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0007] The excavator described above can more accurately calculate the weight of an object being transported to a predetermined location. BRIEF DESCRIPTION OF THE DRAWINGS [ Fig. 1] Fig. 1 is a side view of an excavator. [ Fig. 2] Fig. 2 is a diagram schematically showing a configuration example of an excavator control system. [ Fig. 3] Fig. 3 is a diagram schematically showing a configuration example of an excavator hydraulic system. [ Fig. 4A] Fig. Figure 4A is a partial view of a hydraulic system for arm cylinder operation. [ Fig. 4B] Fig. Figure 4B is a partial view of a hydraulic system for boom cylinder operation. [ Fig. 4C] Fig. Figure 4C is a partial view of a hydraulic system for bucket cylinder operation. [ Fig. 4D] Fig. 4D is a partial view of a hydraulic system for rotating hydraulic motor operation. [ Fig. 4E] Fig. Figure 4E is a partial view of a hydraulic system for operating a left-hand running hydraulic motor. [ Fig. 4F] Fig. Figure 4F is a partial view of a hydraulic system for operating a clockwise rotating hydraulic motor. [ Fig. 5] Fig. 5 is a diagram for describing a flow of a loading operation by an excavator. [ Fig. 6] Fig. 6 is a flowchart showing an example of a setting processing flow. [ Fig. 7] Fig. 7 is a flowchart showing an example of a support processing flow. [ Fig. 8] Fig. 8 is a schematic diagram showing another configuration example of the excavator control system. [ Fig. 9] Fig. Figure 9 is a schematic diagram of an excavator for digging a trench. [ Fig. 10] Fig. 10 is a flowchart showing yet another example of the operation of the excavator control system. [ Fig. 11] Fig. 11 is a plan view of an excavator loading earth and sand onto a dump truck. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an excavator 100 according to an embodiment of the present disclosure will be described with reference to the drawings. First, an overview of the excavator 100 will be described with reference to Fig. 1 described. Fig. 1 is a side view of the excavator 100.

[0009] The excavator 100 includes a lower traveling body (1), an upper rotating body (3) rotatably mounted on the lower traveling body (1) via a rotating device (2), a boom (4), an arm (5) and a bucket (6) forming an excavation attachment as an example of an attachment (AT), and a cabin (10).

[0010] The lower traveling body 1 drives the excavator 100 through a pair of left and right crawlers, each hydraulically driven by a traveling hydraulic motor 2M (see Fig. 2). 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 a single driven part.

[0011] The upper swivel body 3 is driven by a swivel hydraulic motor 2A (see Fig. 2) to swing with respect to the lower traveling body 1. In other words, the swing hydraulic motor 2A is a swing drive section for driving the upper swing body 3 as a driven section and can change the direction of the upper swing body 3.

[0012] The upper swing body 3 may be driven by a swing motor as an electric actuator instead of the swing hydraulic motor 2A of FIG. In other words, the swing motor such as the swing hydraulic motor 2A is a swing drive section for driving the upper swing body 3 as a driven section and can change the direction of the upper swing body 3.

[0013] The boom 4 is rotatably mounted at the front center of the upper swing body 3, the arm 5 is rotatably mounted at the tip of the boom 4, and the bucket 6 is rotatably mounted as an end attachment at the tip of the arm 5. The boom 4, the arm 5, and the bucket 6 are each hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9 as hydraulic actuators.

[0014] The bucket 6 is an example of an end attachment, and other end attachments such as a slope bucket, a dredging bucket, or a crusher may be attached to the tip of the arm 5 instead of the bucket 6 according to the work contents.

[0015] The cabin 10 is an operator cabin in which an operator rides and is provided on the front left side of the upper swing body 3.

[0016] Next, a specific configuration of the excavator 100 will be described with reference to Fig. 2 in addition to Fig. 1 described. Fig. 2 is a diagram schematically showing a configuration example of a control system of the excavator 100. In Fig. 2, a mechanical power transmission line, a hydraulic oil line, a pilot line and an electrical signal line are represented by double lines, solid lines, dashed lines and dotted lines, respectively.

[0017] The drive system of the excavator 100 includes an engine 11, a governor 13, a main pump 14, and a control valve group 17. The hydraulic drive system of the excavator 100 includes hydraulic actuators such as a travel hydraulic motor 2M, a swing hydraulic motor 2A, a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9 for hydraulically driving the lower travel body 1, the upper swing body 3, the boom 4, the arm 5, and the bucket 6, respectively.

[0018] The motor 11 is a power source in a hydraulic drive system and is mounted, for example, on the rear side of the upper rotating body 3. Specifically, the motor 11 rotates at a predetermined target speed under direct or indirect control by a controller 30 to drive the main pump 14 and a pilot pump 15. The motor is, for example, a diesel engine.

[0019] The controller 13 controls a discharge amount of the main pump 14. For example, the controller 13 adjusts the angle (inclination angle) of a swash plate of the main pump 14 according to a control command of the controller 30. The controller 13 includes, for example, a left controller 13L and a right controller 13R (see Fig. 3).

[0020] The main pump 14 is mounted, for example, on the rear side of the upper swing body 3 and supplies hydraulic oil to the control valve group 17 via a hydraulic oil line. The main pump 14 is driven by the engine 11. The main pump 14 is, for example, a variable displacement hydraulic pump, and under the control of the controller 30, the inclination angle of the swash plate is adjusted by the regulator 13 to adjust a stroke length of a piston and thereby control a discharge flow rate (displacement volume). The main pump 14 includes, for example, a left main pump 14L and a right main pump 14R (see Fig. 3).

[0021] The control valve group 17 is, for example, a hydraulic control device mounted in a central portion of the upper swing body 3 and controls the hydraulic drive system in response to an operator's operation of an operating device 26. The control valve group 17 is connected to the main pump 14 via the hydraulic oil line and selectively supplies the hydraulic oil supplied from the main pump 14 to each of the plurality of hydraulic actuators (travel hydraulic motor 2M, swing hydraulic motor 2A, boom cylinder 7, arm cylinder 8, and bucket cylinder 9) in response to an operating state of the operating device 26. More specifically, the control valve group 17 includes control valves 171 to 176 for controlling a flow rate and a flow direction of the hydraulic oil supplied from the main pump 14 to each of the hydraulic actuators.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. 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 and 176R (see . Fig. 3).

[0022] An operating system of the excavator 100 includes the pilot pump 15 and the operating device 26. An operating system of the excavator 100 includes a solenoid valve 31 as a configuration connected to a machine control function by the controller 30.

[0023] The pilot pump 15, for example, is mounted on the rear of the upper rotary body 3 and supplies pilot pressure to each pilot port of the control valves 171 to 176 via the pilot line. The pilot pump 15 is, for example, a fixed-displacement hydraulic pump and is driven by the motor 11.

[0024] The operating device 26 is provided near the operator's seat in the cab 10 and is an operation input means for an operator to operate various operating elements (lower traveling body 1, upper slewing body 3, boom 4, arm 5, bucket 6, etc.). In other words, the operating device 26 is an operation input means for an operator to operate a hydraulic actuator (travel hydraulic motor 2M, slewing hydraulic motor 2A, boom cylinder 7, arm cylinder 8, bucket cylinder 9, etc.) to drive each operating element. At each pilot port of the control valves 171 to 176, a pilot pressure corresponding to the operation content (operation direction and operation amount) of the operating device 26 is input. In the illustrated example, the operating device 26 includes a left operation lever 26L (see Fig. 4A), which is a lever device for operating the upper rotary body 3 (rotary hydraulic motor 2A) and the arm 5 (arm cylinder 8), a right operating lever 26R (see Fig. 4B), which is a lever device for operating the boom 4 (boom cylinder 7) and the bucket 6 (bucket cylinder 9), and a travel control device 26D (see Fig. 4E), which operates the crawler (travel hydraulic motor 2M) of the lower traveling body 1. The travel control device 26D comprises a left travel lever 26DL (see Fig. 4E) to operate the left crawler (left travel hydraulic motor 2ML) and a right travel lever 26DR (see Fig. 4F) for operating the right crawler (right travel hydraulic motor 2MR). The operating device 26D may include a left accelerator pedal for operating the left crawler (left travel hydraulic motor 2ML) and a right accelerator pedal for operating the right crawler (right travel hydraulic motor 2MR).

[0025] In the illustrated example, the operating device 26 is of an electric type for outputting an electric signal, and the electric signal from the operating device 26 is input to the controller 30. The controller 30 controls the pilot pressure acting on the pilot ports of the control valves 171 to 176 according to the electric input signal, thereby achieving the operation of the various hydraulic actuators according to the operation content of the operating device 26. Specifically, the solenoid valve 31, which operates according to the electric signal from the controller 30, is arranged between the pilot pump 15 and the pilot ports of the control valves 171 to 176.When the control device 26 is operated, the controller 30 controls the solenoid valve 31 according to the electrical signal corresponding to an operation amount (e.g., lever operation amount) thereof to increase or decrease the pilot pressure, thereby allowing the control valves 171 to 176 to operate according to the operation content of the control device 26. The control valves 171 to 176 may be a solenoid valve controlled according to a command from the controller 30.

[0026] The control system of the excavator 100 includes the controller 30, a discharge pressure sensor 28, an operation sensor 29, the solenoid valve 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 machine body inclination sensor S4, a rotation state sensor S5, an imaging device S6, a positioning device Q1, and a communicator T1.

[0027] The controller 30 (an example of a control device) is provided in the cab 10 and is configured to control the drive of the excavator 100. The functions of the controller 30 can be implemented by any hardware, software, or a combination thereof. In the example shown, the controller 30 is configured around a microcomputer including a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), a non-volatile auxiliary storage device, and various input / output interfaces. The controller 30 implements various functions by executing various programs stored, for example, in the ROM or the non-volatile auxiliary storage device of the CPU.

[0028] In the illustrated example, the controller 30 controls a target rotational speed based on a working mode or the like set in advance by a predetermined operation by an operator or the like, and performs drive control to rotate the motor 11 at a constant rotational speed. The controller 30 can output a control command to the regulator 13 to change the discharge amount of the main pump 14 as needed.

[0029] The controller 30 may be configured to control a machine guidance function to guide manual operation of the excavator 100 by an operator via the operating device 26. The controller 30 may be configured to control a machine control function to automatically support manual operation of the excavator 100 by an operator via the operating device 26. In this case, the controller 30 may include a machine guidance part 50 as a functional part associated with the machine guidance function and the machine control function.

[0030] Part of the function of the controller 30 may be implemented by another controller (control device). That is, the function of the controller 30 may be implemented in a distributed manner across multiple controllers. For example, the machine guidance function and the machine control function may be implemented by a dedicated controller (control device).

[0031] The discharge pressure sensor 28 detects the discharge pressure of the main pump 14. A detection signal corresponding to a 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 (see Fig. 3).

[0032] The operation sensor 29 detects the operation contents (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 (see Fig. 4A) for detecting the operation content of the left operating lever 26L in a longitudinal direction (arm operating direction), an operation sensor 29RA (see Fig. 4B) for detecting the operating content of the right operating lever 26R in the longitudinal direction (boom operating direction), an operating sensor 29RB (see Fig. 4C) for detecting the operation content of the right control lever 26R in a lateral direction (bucket operation direction), an operation sensor 29LB (see Fig. 4D) for detecting the operation content of the left operating lever 26L in a lateral direction (rotational operation direction), an operation sensor 29DL (see Fig. 4E) for detecting the operating content of the left drive lever 26DL, and an operating sensor 29DR (see Fig. 4F) for detecting the operating content of the right drive lever 26DR.

[0033] In the example shown, the operation sensor 29 is an inclination sensor capable of detecting the operation amount (inclination amount) and the inclination direction of the operating device 26, but may also be any sensor such as an encoder or a potentiometer.

[0034] The solenoid valve 31 is provided in a pilot line connecting the pilot pump 15 and the respective pilot ports of the control valves 171 to 176, and is configured to be capable of changing a flow path area (cross-sectional area through which hydraulic oil can flow). The solenoid valve 31 operates in response to an input of a control command from the controller 30. Thus, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the respective control ports of the control valves 171 to 176 via the solenoid valve 31, even when the operating device 26 is not operated by an operator. In the illustrated example, the solenoid valve 31 includes a solenoid valve 31AL to a solenoid valve 31FL and a solenoid valve 31AR to a solenoid valve 31FR, as shown in Fig. 4A to 4F.

[0035] The display device 40 is provided in the cab 10 at a location easily visible to an operator sitting in the driver's seat 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 communications network or via a one-to-one dedicated line.

[0036] The input device 42 is provided within the reach of an operator sitting in the driver's seat in the cab 10, receives various input operations from the operator, and outputs signals corresponding to the inputs to the controller 30. The input device 42 may be, for example, a touch panel mounted on a screen of the display device 40 for displaying various information, a toggle switch provided at a tip of the lever portion of the lever device, and a knob switch, a lever, a rocker switch, or a rotary switch provided around the display device 40. A signal corresponding to an operation of the input device 42 is input to the controller 30.

[0037] The input device 42 includes a mode switch 42a. The mode switch 42a is a switch for switching the operation mode of the excavator 100. The operation mode indicates a type of operation performed by the excavator 100 and includes, for example, a crane mode, a normal mode, and the like. The mode switch 42a may be a software switch displayed on the screen of the display device 40, a hardware switch installed around the display device 40, or a switch installed elsewhere in the cab 10.

[0038] The sound output device 43 is provided in the cabin 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. The sound output device 43 audibly outputs various types of information in response to a sound output command from the controller 30.

[0039] The storage device 47 is provided, for example, in the cab 10 and stores various types of 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 information output from various devices during the operation of the excavator 100, or can store information obtained by various devices before the start of the operation of the excavator 100. The storage device 47 can store, for example, data about a target point acquired via the communicator T1 or set via the input device 42 or the like. The target point is, for example, a point on a target construction area.The data relating to the target point may be set (stored) by an operator of the excavator 100 or set by a construction manager or the like.

[0040] The boom angle sensor S1 is attached to the boom 4 and detects a rotation angle (hereinafter referred to as "boom angle") of the boom 4 with respect to the upper slewing body 3, for example, an angle formed by a straight line connecting points (centers of connecting pins) at both ends of the boom 4 with respect to a rotation plane (a plane perpendicular to a rotation axis) of the upper slewing body 3 in a side view. The boom angle sensor S1 is, for example, a rotary encoder, an acceleration sensor, a 6-axis sensor, an inertial measurement unit (IMU), or a combination thereof. The boom angle sensor S1 may include a potentiometer using a variable resistor, a cylinder sensor for detecting a stroke amount of a hydraulic cylinder (boom cylinder 7) corresponding to the boom angle, or the like.The same applies to the arm angle sensor S2 and the bucket angle sensor S3. A detection signal from the boom angle sensor S1 corresponding to the boom angle is transferred to the controller 30.

[0041] The arm angle sensor S2 is attached to the arm 5 and detects a rotation angle (hereinafter referred to as "arm angle") of the arm 5 with respect to the boom 4, for example, an angle formed by a straight line connecting points at both ends of the arm 5 (centers of the connecting pins) with respect to a straight line connecting points at both ends of the boom 4 (centers of the connecting pins) in a side view. A detection signal of the arm angle sensor S2 corresponding to the arm angle is input to the controller 30.

[0042] The bucket angle sensor S3 is attached to the bucket 6 and detects a rotation angle (hereinafter referred to as "bucket angle") of the bucket 6 with respect to the arm 5, for example, an angle formed by a straight line connecting the pivot point (center of the connecting pins) and the tip (toe) of the bucket 6 with respect to a straight line connecting points at both ends of the arm 5 (centers of the extension pieces) in a side view. A detection signal of the bucket angle sensor S3 corresponding to the bucket angle is input to the controller 30. The bucket angle sensor S3 may be omitted. In this case, the controller 30 can estimate the bucket angle based on the output of the operation sensor 29RB.

[0043] The machine body tilt sensor S4 detects a tilt state of the machine body (upper slewing body 3 or lower traveling body 1) with respect to a horizontal plane. The machine body tilt sensor S4 is mounted, for example, on the upper slewing body 3 and detects a tilt angle (hereinafter, the "longitudinal tilt angle" and the "lateral tilt angle") of the excavator 100 (namely, the upper slewing body 3) about two axes in the longitudinal direction and the lateral direction. The machine body tilt sensor S4 is, for example, a rotary encoder, an acceleration sensor, a 6-axis sensor, the IMU, or a combination thereof. The detection signal of the machine body tilt sensor S4 corresponding to the tilt angle (longitudinal tilt angle and lateral tilt angle) is input to the controller 30.

[0044] A rotation state sensor S5 outputs information about the rotation state of the upper rotating body 3. The rotation state sensor S5 detects, for example, the rotational angular velocity of the upper rotating body 3. The rotation state sensor S5 can detect the rotation angle. The rotation state sensor S5 is, for example, a gyro sensor, a resolver, or a rotary encoder. A detection signal from the rotation state sensor S5 corresponding to the rotational angular velocity of the upper rotating body 3 is transferred to the controller 30.

[0045] An imaging device S6 as a spatial recognition device images the surroundings of the excavator 100. In the illustrated example, the imaging device S6 includes a camera S6F for imaging the front of the excavator 100, a camera S6L for imaging the left side of the excavator 100, a camera S6R for imaging the right side of the excavator 100, and a camera S6B for imaging the rear of the excavator 100. The imaging device S6 can be directly connected to the controller 30 in a communicable manner.

[0046] In the example shown, the camera S6F is mounted on the ceiling of the cabin 10, i.e., inside the cabin 10. The camera S6F can also be mounted outside the cabin 10, for example, on the roof of the cabin 10 or on a side of the boom 4. The camera S6L is mounted at a left end of an upper surface of the upper swing body 3, the camera S6R is mounted at a right end of the upper surface of the upper swing body 3, and the camera S6B is mounted at a rear end of the upper surface of the upper swing body 3.

[0047] Each of the imaging devices S6 (camera S6F, camera S6B, camera S6L, and camera S6R) is, for example, a monocular wide-angle camera with a wide angle of view. Each of the imaging devices S6 may be a stereo camera, a rangefinder camera, or the like. The images captured by each imaging device S6 are transferred to the controller 30 via the display device 40.

[0048] The imaging device S6 as the space recognition device may function as an object detection device. In this case, the imaging device S6 may detect an object located around the excavator 100. The object to be detected may include, for example, a person, an animal, a vehicle, a construction machine, a building, a hole, or the like. The imaging device S6 as the object detection device may calculate a distance to the object detected by the imaging device S6 or the excavator bucket 100. The imaging device S6 as the object detection device may be a stereo camera, a distance image sensor, or the like. Specifically, the imaging device S6 is a monocular camera that includes an imaging element such as a CCD or a CMOS and outputs the captured image to the display device 40.

[0049] In addition to the imaging device S6, the excavator 100 may be equipped with another object detection device such as an ultrasonic sensor, a millimeter-wave radar, a LIDAR, an infrared sensor, or the like as the spatial detection device. The millimeter-wave radar, ultrasonic sensor, a laser radar, or the like as the spatial detection device can emit a large number of signals (laser light, etc.) to an object and detect the distance and direction of the object from a reflected signal by receiving the reflected signal.

[0050] A boom rod pressure sensor S7R and a boom ground pressure sensor S7B are mounted on the boom cylinder 7. An arm rod pressure sensor S8R and a pressure sensor for the arm ground pressure sensor S8B are mounted on the arm cylinder 8. A bucket rod pressure sensor S9R and a bucket ground pressure sensor S9B are mounted on the bucket cylinder 9. At least one of the boom rod pressure sensor S7R, boom ground pressure sensor S7B, arm rod pressure sensor S8R, arm ground pressure sensor S8B, bucket rod pressure sensor S9R, or bucket ground pressure sensor S9B is also collectively referred to as a "cylinder pressure sensor."

[0051] The boom rod pressure sensor S7R detects the pressure (hereinafter referred to as “boom rod pressure”) in a rod-side oil chamber of the boom cylinder 7, and the boom bottom pressure sensor S7B detects the pressure (hereinafter referred to as “boom bottom pressure”) in a bottom-side oil chamber of the boom cylinder 7. The arm rod pressure sensor S8R detects the pressure (hereinafter referred to as “arm rod pressure”) in a rod-side oil chamber of the arm cylinder 8, and the arm bottom pressure sensor S8B detects the pressure (hereinafter referred to as “arm bottom pressure”) in a bottom-side oil chamber of the arm cylinder 8. The bucket rod pressure sensor S9R detects the pressure (hereinafter referred to as “bucket rod pressure”) in a rod-side oil chamber of the bucket cylinder 9, and the bucket bottom pressure sensor S9B detects the pressure (hereinafter referred to as “bucket bottom pressure”) in a bottom oil chamber of the bucket cylinder 9.

[0052] 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 Global Navigation Satellite System (GNSS) 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. The orientation of the upper rotating body 3 may be detected by another device, such as an orientation sensor attached to the upper rotating body 3.

[0053] The communicator T1 is configured to communicate with an external device via any communication network, including a mobile communication network, a satellite communication network, or an Internet network. More particularly, the communicator T1 may be configured with a cellular module conforming to a cellular standard such as LTE (Long Term Evolution), 4G (4th generation), or 5G (5th generation), or with a satellite communication module for connecting to the satellite communication network.

[0054] The machine guidance part 50 is configured to perform a machine guidance function. In the illustrated example, the machine guidance part 50 transmits work information such as a distance between a target point and a control point (e.g., a working portion of the end attachment) to the operator via the display device 40 or the sound output device 43. Data related to the target point is stored in advance 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, a geodetic world system. The geodetic world system is a three-dimensional orthogonal XYZ coordinate system in which the origin is located at the center of gravity of the earth, the X-axis is in a direction of the intersection of the Greenwich meridian and the equator, and the Y-axis is in a direction of the 90th degree.east longitude, and the Z-axis runs in a direction toward the North Pole. The operator can set any point on the construction site as a reference point via the input device 42 and set a relative positional relationship between the reference point and the target point. The working portion of the end attachment is, for example, the tip of the bucket 6 or the rear of the bucket 6. The machine guidance part 50 communicates work information to the operator via the display device 40 or the sound output device 43 and guides the operator's operation of the excavator 100 via the operation device 26.

[0055] The machine control part 50 may be configured to perform a machine control function. For example, the machine control part 50 may automatically control at least one of the swing hydraulic motor 2A, the travel hydraulic motor 2M, the boom 4, the arm 5, or the bucket 6 so that the target point and the control point (a point on the working portion of the end attachment) coincide when the operator performs a manual operation.

[0056] In the illustrated example, the machine control part 50 receives information from the boom angle sensor S1, the arm angle sensor S2, the bucket angle sensor S3, the machine body inclination sensor S4, the rotation state sensor S5, the imaging device S6, the positioning device Q1, the communicator T1, the input device 42, and the like. Based on the acquired information, the machine control part 50 calculates the distance between the target point and the control point, notifies the operator of the distance between the target point and the control point through sound from the sound output device 43 and an image displayed on the display device 40, and automatically controls the operation of the actuator so that the control point and the target point coincide.As functional elements related to the machine guidance function and the machine control function, the machine guidance part 50 includes a position calculator 51, a distance calculator 52, an information transmitter 53, an automation controller 54, an excavation reaction force calculator 55, a target specifier 56, and an excavation support part 57.

[0057] The position calculator 51 is configured to calculate the position of a predetermined positioning object. For example, the position calculator 51 calculates the coordinates of the control point in the reference coordinate system. Specifically, the position calculator 51 calculates the coordinates of the control point from the travel distance of the lower traveling body 1, the rotation 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.

[0058] The distance calculator 52 is configured to calculate the distance between two positioning objects. In the example shown, the distance calculator 52 calculates the distance between the control point and the target point. For example, the distance calculator 52 calculates the distance between a control point at the tip of the bucket 6 and a point on the target construction surface.

[0059] The information transmitter 53 transmits (notifies) various information to the operator of the excavator 100 via a notification means such as the display device 40 or the sound output device 43. The information transmitter 53 can notify the operator of the excavator 100 of the magnitudes of the various distances or the like calculated by the distance calculator 52. For example, the information transmitter 53 can use at least one of the visual information of the display device 40 or the auditory information of the sound output device 43 to inform the operator of the magnitude of the distance between the control point and the target point.

[0060] Specifically, the information transmitter 53 may use intermittent tones of the sound output device 43 to inform the operator of the distance between the control point and the target point. In this case, the information transmitter 53 may shorten the interval between the intermittent tones as the distance decreases and lengthen the interval between the intermittent tones as the distance increases. Furthermore, the information transmitter 53 may use continuous tones and indicate the difference in the distance by changing the pitch or intensity of the tones. Furthermore, the information transmitter 53 may issue an alarm via the sound output device 43 when the control point at the tip of the bucket 6 is lower than the target construction area, that is, when the control point exceeds the target construction area. The alarm is, for example, a continuous tone, which is significantly longer than an intermittent tone.

[0061] Furthermore, the information transmitter 53 can cause the display device 40 to display the distance between the control point and the target point as work information. The display device 40 can display the work information received by the information transmitter 53 together with the image data received from the imaging device S6 under the control of the controller 30. The information transmitter 53 can use an image from an analog meter, an image from a bar graph, or the like to notify the operator of the distance.

[0062] The automation controller 54 automatically supports the manual operation of the excavator 100 by the operator via the operating device 26 by automatically actuating the actuator. In particular, the controller 54 can individually and automatically adjust the pilot pressure at the pilot port of the control valve for each of the plurality of hydraulic actuators. Thus, the automation controller 54 can automatically actuate the respective hydraulic actuators. Control of the machine control function by the automation controller 54 can occur, for example, when a predetermined switch comprising the input device 42 is pressed.The predetermined switch is, for example, a machine control switch (hereinafter "machine control switch (MC)") and may be arranged as a toggle switch at a tip of a handle portion of the operating device 26 (for example, an arm operating lever, which is a lever device used to operate the arm 5). The following description refers to a machine control function performed when the MC switch is operated.

[0063] For example, when the MC switch or the like is pressed, the controller 54 automatically extends or retracts the boom cylinder 7 or the bucket cylinder 9 according to the operation of the boom operation lever 8 to assist excavation work. Specifically, when the operator manually closes the arm 5 (hereinafter, "arm closing operation"), the controller 54 automatically extends or retracts the boom cylinder 7 or the bucket cylinder 9 so that a target point on the target construction surface coincides with a control point on the construction site, such as the tip or rear surface of the bucket 6. In this case, the operator can close the arm 5 while aligning the tip of the bucket 6 or the like with the target surface by simply operating the arm operation lever, for example, in an arm closing direction.

[0064] The excavation reaction force calculator 55 is configured to derive an excavation reaction force. The excavation reaction force is the reaction force of the excavation force, has the same magnitude as the excavation force, and is a force in a direction opposite to that of the excavation force. In the illustrated example, the excavation reaction force calculator 55 derives an excavation reaction force based on the posture of the excavator attachment and the load acting on the attachment. The posture of the attachment is detected by a posture sensor. The posture sensor includes at least one of the boom angle sensor S1, the arm angle sensor S2, or the bucket angle sensor S3. The load acting on the attachment is detected by the cylinder pressure sensor.The cylinder pressure sensor includes at least one of the boom rod pressure sensor S7R, the boom bottom pressure sensor S7B, the arm rod pressure sensor S8R, the arm bottom pressure sensor S8B, the bucket rod pressure sensor S9R, or the bucket bottom pressure sensor S9B.

[0065] Specifically, the excavation reaction force calculator 55 repeatedly calculates the excavation reaction force at a predetermined calculation period using a predetermined calculation formula. The excavation reaction force calculator 55 calculates the excavation reaction force such that the deeper the excavation depth, that is, the greater a vertical distance between the contact surface of the excavator 100 and the tip of the bucket 6, the greater the excavation reaction force. Furthermore, the excavation reaction force calculator 55 calculates the excavation reaction force such that the greater the soil penetration depth, which is the depth of the tip of the bucket 6 in the soil to be excavated, the greater the excavation reaction force. The excavation reaction force calculator 55 can also calculate the excavation reaction force taking into account soil and sand properties such as soil and sand density.The soil and sand properties may be values ​​input by an operator via input device 42 or the like, or may be values ​​automatically calculated based on the outputs of various sensors, such as the cylinder pressure sensor. The excavation reaction force calculator 55 may be configured to calculate at least one of a horizontal component or a vertical component of the excavation reaction force.

[0066] The target specifier 56 is configured to set a target value related to the excavation operation. In the illustrated example, the target specifier 56 is configured to determine whether or not a predetermined excavation operation suitable for calculating the target value has been performed based on information regarding the excavation operation performed by the attachment AT with respect to a construction object (excavation target soil) at the construction site, and to set a target value based on the excavation reaction force calculated when the excavation operation is determined to be the predetermined excavation operation. The target specifier 56 can determine that the predetermined excavation operation has been performed when the predetermined excavation operation has been performed a predetermined number of times.That is, even if the predetermined excavation operation has been performed, the target specifier 56 may determine that the predetermined excavation operation has not been performed if the number of times the predetermined excavation operation is performed is less than the predetermined number of times. Hereinafter, the excavation operation performed before setting the target value may be referred to as a "first excavation operation," and the excavation operation performed after setting the target value may be referred to as a "second excavation operation."

[0067] The information related to the excavation process is information related to an excavated amount, such as the amount of soil and sand taken up in the bucket 6. The amount of soil and sand taken up in the bucket 6 is typically the volume of soil and sand contained in the bucket 6 in the air after the excavation process and before the unloading process. The amount of soil and sand can be calculated, for example, based on an image of the bucket 6 in the air taken by the camera S6F. Alternatively, the amount of soil and sand taken up in the bucket 6 can be estimated based on an image of the ground (the ground above the bucket 6 in the ground) taken by the camera S6F.Specifically, the amount of soil and sand may be estimated based on a state of the soil lifted by the movement of the bucket 6 in the second half of the excavation process (the movement of the bucket 6 lifted from the ground by a boom lifting process). Alternatively, the amount of soil and sand held in the bucket 6 may be estimated based on an image of the soil before the excavation process and an image of the soil after the excavation process taken by the camera S6F. Specifically, the amount of soil and sand may be estimated based on a change in the shape of the soil before and after the excavation process. Alternatively, the amount of soil and sand held in the bucket 6 may be determined from the weight of the soil and sand held in the bucket 6.For example, the weight of the earth and sand can be calculated based on the output of the position sensor and an output of the cylinder pressure sensor.

[0068] When the amount of soil and sand filled into the bucket 6 has been obtained, the target specifier 56 determines that a predetermined excavation operation suitable for calculating the target value has been performed when it can be detected that the bucket 6 is filled with soil and sand, or when it can be detected that the amount of soil and sand accommodated in the bucket 6 is greater than a predetermined amount (predetermined volume or predetermined weight), such as when it can be detected that the amount of soil and sand accommodated in the bucket 6 is 80% or 90% of the capacity of the bucket 6.

[0069] The information related to the excavation operation may be information input by the operator of the excavator 100. The information input by the operator of the excavator 100 is, for example, information that notifies the controller 30 that the operator has determined that a predetermined excavation operation has been performed. For example, the operator of the excavator 100 may notify the controller 30 that the operator has determined that a predetermined excavation operation has been performed by pressing a predetermined button, which is one of the input devices 42.

[0070] The predetermined excavation operation is an excavation operation suitable for calculating a target value, and may be, for example, an excavation operation in which the bucket 6 can be filled with earth and sand, or an excavation operation in which earth and sand can be accommodated up to 80% or 90% of the capacity of the bucket 6.

[0071] The target value is a value used to reproduce the predetermined excavation operation and may, for example, be a maximum value (maximum excavation reaction force) of the excavation reaction force calculated and recorded when the predetermined excavation operation was performed. The target value may be a value calculated based on the maximum value of the excavation reaction force. For example, the target value may be a value obtained by adding a predetermined value to the maximum value of the excavation reaction force or by subtracting a predetermined value from the maximum value of the excavation reaction force. The target value may be a maximum value of the horizontal component of the excavation reaction force or a maximum value of the vertical component of the excavation reaction force. The target value may be a value calculated and recorded based on a transition of the excavation reaction force when the predetermined excavation operation is performed.

[0072] The target value may be an average value of the maximum values ​​of the excavation reaction force in each of a plurality of predetermined excavation operations, that is, an average value of a plurality of maximum excavation reaction forces (maximum average excavation reaction force). The target value may be a median value, a mode value, or the like of a plurality of maximum excavation reaction forces.

[0073] The target specifier 56 can derive a correlation between the maximum value of the excavation reaction force and the excavation amount in each of one or more excavation operations, and then set the excavation reaction force corresponding to a desired excavation amount as the target value. In this case, the desired excavation amount, for example, 80% or 90% of the capacity of the bucket 6, can be a preset excavation amount or an excavation amount input via the device 42. The correlation can be stored as a calculation formula, such as a linear equation or quadratic equation, or as a reference table.

[0074] The excavation support part 57 is configured to support the excavation operation performed by the operator of the excavator 100. In the illustrated example, the excavation support part 57 is configured to support each excavation operation after the target value is set by the target specifier 56. Specifically, when the excavation reaction force value repeatedly calculated during the excavation operation reaches the target value, the excavation support part 57 notifies the operator of the excavator 100 that the excavation reaction force value has reached the target value via a notification means such as the display device 40 or the sound output device 43. At this time, the operator performs the boom lifting operation to raise the bucket 6, which is at least partially underground, into the air, thereby completing the excavation operation in a state where the bucket 6 is filled with soil and sand.

[0075] The excavation support part 57 can automatically actuate one or more actuators when the excavation reaction force reaches the target value. Automatic actuation of the actuators means that the actuators are actuated independently of the operation by the operating device 26. In the illustrated example, the actuator is at least one of the boom cylinder 7, the arm cylinder 8, or the bucket cylinder 9. In the illustrated example, when the excavation reaction force reaches the target value, the excavation support part 57 automatically extends the boom cylinder 7, raises the boom 4, and lifts the bucket 6, which is at least partially underground, into the air, thereby completing the excavation operation in a state where the bucket 6 is filled with soil and sand.When the excavation reaction force reaches the target value, the excavation support part 57 can stop the excavation operation through the excavation attachment even when the operator performs the operation of the operating device 26. After the excavation operation is stopped, the operator raises the boom 4 and lifts the bucket 6, which is at least partially underground, into the air, thereby completing the excavation operation in a state where the bucket 6 is filled with soil and sand.

[0076] After the target value is set by the target specifier 56, the excavation support part 57 may be configured to support the excavation operation performed by the operator of the excavator 100 even if the excavation reaction force value repeatedly calculated during the excavation operation does not reach the target value. For example, the excavation support part 57 may automatically operate one or more actuators so that the working portion of the end attachment (the tip of the bucket 6) moves linearly until the excavation reaction force value reaches the target value. Specifically, the excavation support part 57 may automatically control at least one of the boom cylinder 7, the arm cylinder 8, or the bucket cylinder 9 so that the tip of the bucket 6 moves linearly along a ground plane, the horizontal plane, a target construction plane, or the like during the excavation operation.In this case, for example, the operator of the excavator 100 can move the tip of the bucket 6 linearly under the ground along the ground plane, the horizontal plane, the target construction plane, or the like until the excavation reaction force value reaches the target value simply by performing the arm closing operation. When the excavation reaction force value reaches the target value, the operator can lift the bucket 6, which is at least partially under the ground, into the air and complete the excavation operation in a state where the interior of the bucket 6 is filled with soil and sand. This configuration is effective, for example, when excavating a trench with a certain depth.

[0077] Next, the hydraulic system of the excavator 100 will be described with reference to Fig. 3 described. Fig. 3 is a diagram schematically showing an example of the configuration of the hydraulic system of the excavator 100. In Fig. 3, the mechanical power transmission line, the hydraulic oil line, the pilot line and the electrical signal line are represented by double lines, solid lines, dashed lines and dotted lines respectively, as is also the case in Fig. 2 and the like.

[0078] The hydraulic system circulates hydraulic oil from the left main pump 14L driven by the engine 11 via a left central bypass oil path C1L and a left parallel oil path C2L to a hydraulic oil tank and circulates hydraulic oil from the right main pump 14R driven by the engine 11 via a right central bypass oil path C1R and a right parallel oil path C2R to the hydraulic oil tank.

[0079] The left central bypass oil path C1L starts from the left main pump 14L and passes sequentially through the control valve 171, the control valve 173, the control valve 175L and the control valve 176L arranged in the control valve group 17 to reach the hydraulic oil tank.

[0080] The right central bypass oil path C1R starts from the right main pump 14R and passes sequentially through the control valve 172, the control valve 174, the control valve 175R and the control valve 176R arranged in the control valve group 17 to reach the hydraulic oil tank.

[0081] The control valve 171 is a spool valve for supplying the hydraulic oil discharged from the left main pump 14L to the left travel hydraulic motor 2ML and discharging the hydraulic oil discharged from the left travel hydraulic motor 2ML to the hydraulic oil tank.

[0082] The control valve 172 is a spool valve for supplying the hydraulic oil discharged from the right main pump 14R to the right travel hydraulic motor 2MR and discharging the hydraulic oil discharged from the right travel hydraulic motor 2MR into the hydraulic oil tank.

[0083] The control valve 173 is a spool valve that supplies the hydraulic oil discharged from the left main pump 14L to the swing hydraulic motor 2A and discharges the hydraulic oil discharged from the swing hydraulic motor 2A to the hydraulic oil tank.

[0084] The control valve 174 is a spool valve that supplies the hydraulic oil discharged from the right main pump 14R to the bucket cylinder 9 and discharges the hydraulic oil in the bucket cylinder 9 into the hydraulic oil tank.

[0085] 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 hydraulic oil discharged from the left main pump 14L to the boom cylinder 7 and discharges the hydraulic oil in the boom cylinder 7 into the hydraulic oil tank. The control valve 175R is a spool valve that supplies the hydraulic oil discharged from the right main pump 14R to the boom cylinder 7 and discharges the hydraulic oil in the boom cylinder 7 into the hydraulic oil tank.

[0086] 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 hydraulic oil discharged from the left main pump 14L to the arm cylinder 8 and discharges the hydraulic oil in the arm cylinder 8 into the hydraulic oil tank. The control valve 176R is a spool valve that supplies the hydraulic oil discharged from the right main pump 14R to the arm cylinder 8 and discharges the hydraulic oil in the arm cylinder 8 into the hydraulic oil tank.

[0087] Each of the control valves 171 to 176 adjusts the flow rate of the hydraulic oil supplied to the hydraulic actuator and switches the flow direction according to the pilot pressure acting on the pilot port.

[0088] The left parallel oil path C2L is arranged parallel to the left central bypass oil path C1L and is configured to supply the hydraulic oil discharged from the left main pump 14L to the control valve 173, the control valve 175L, and the control valve 176L, respectively. Thus, the left parallel oil path C2L can supply the hydraulic oil to the control valve further downstream when the flow of hydraulic oil through the left central bypass oil path C1L is restricted or blocked by one of the control valves 171, 173, or 175L.

[0089] The right parallel oil path C2R is arranged parallel to the right central bypass oil path C1R and is configured to supply the hydraulic oil discharged from the right main pump 14R to the control valve 174, the control valve 175R, or the control valve 176R, respectively. Thus, the right parallel oil path C2R can supply the hydraulic oil to the control valve further downstream when the flow of hydraulic oil through the right central bypass oil path C1R is limited or blocked by the control valve 172, the control valve 174, or the control valve 175R.

[0090] The left regulator 13L is configured to adjust the discharge amount of the left main pump 14L by adjusting the swash plate inclination angle of the left main pump 14L under the control of the controller 30. The right regulator 13R is configured to adjust the discharge amount of the right main pump 14R by adjusting the swash plate inclination angle of the right main pump 14R under the control of the controller 30.

[0091] 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 control the right regulator 13R depending on the discharge pressure of the right main pump 14R.

[0092] In the left central bypass oil path C1L, a left throttle 18L is provided between the downstreammost control valve 176L and the hydraulic oil tank. Thus, the flow of hydraulic oil discharged from the left main pump 14L is restricted by the left throttle 18L. The left throttle 18L generates the left pilot pressure to control the left regulator 13L. The right central bypass oil path C1R is provided with a right throttle 18R between the downstreammost control valve 176R and the hydraulic oil tank. Thus, the flow of hydraulic oil discharged from the right main pump 14R is restricted by the right throttle 18R. The right throttle 18R generates the right pilot pressure to control the right regulator 13R.

[0093] A left control pressure sensor 19L detects the left control pressure, and a detection signal corresponding to the detected left control pressure is supplied to the controller 30. A 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.

[0094] The controller 30 can control the left regulator 13L and adjust the discharge amount of the left main pump 14L according to the discharge pressure of the left main pump 14L detected by the left discharge pressure sensor 28L. For example, the controller 30 can decrease the discharge amount of the left main pump 14L by controlling the left regulator 13L and adjusting the swash plate inclination angle of the left main pump 14L according to an increase in the discharge pressure of the left main pump 14L. The same applies to the right regulator 13R. Thus, the controller 30 can control the total power (total horsepower) of the main pump 14 so that the absorbed power (horsepower) of the main pump 14, represented by the product of the discharge pressure and the discharge amount, does not exceed the power (horsepower) output by the engine 11.

[0095] The controller 30 can also control the left regulator 13L according to the left pilot pressure detected by the left pilot pressure sensor 19L, thus adjusting the discharge amount of the left main pump 14L. For example, the controller 30 decreases the discharge amount of the left main pump 14L when the left pilot pressure increases, and increases the discharge amount of the left main pump 14L when the left pilot pressure decreases. The same applies to the discharge amount of the right main pump 14R.

[0096] Especially in a standby state (as in Fig. 3) in which no hydraulic actuator of the excavator 100 is operated, the hydraulic oil discharged from the left main pump 14L flows through the left central bypass oil path C1L and reaches the left throttle 18L. The flow of the hydraulic oil discharged from the left main pump 14L increases the left pilot pressure generated before the left throttle 18L. As a result, the controller 30 reduces the discharge amount of the left main pump 14L to a minimum allowable discharge amount and suppresses a pressure loss (pumping loss) when the hydraulic oil discharged from the left main pump 14L passes through the left central bypass oil path C1L. The same applies to the pressure loss (pumping loss) when the hydraulic oil discharged from the right main pump 14R flows through the right central bypass oil path C1R.

[0097] When one of the hydraulic actuators is operated via the operating device 26, the hydraulic oil discharged from the left main pump 14L flows into the hydraulic actuator via a control valve corresponding to the hydraulic actuator to be operated. Accordingly, due to a flow direction, the amount of hydraulic oil discharged from the left main pump 14L and reaching the left throttle 18L is reduced or eliminated, thereby reducing the left pilot pressure generated upstream of the left throttle 18L. As a result, the controller 30 increases the discharge amount of the left main pump 14L, circulates sufficient hydraulic oil to the hydraulic actuator to be operated, and can reliably drive the hydraulic actuator to be operated. The same applies to the hydraulic oil discharged from the right main pump 14R.

[0098] Next, the configuration in which the controller 30 controls the actuators will be described with reference to Fig. 4A to 4F. Fig. 4A to 4F are views in which a part of the hydraulic system is extracted. In particular, Fig. 4A is a view in which a part of the hydraulic system for operating the arm cylinder 8 is extracted, and Fig. 4B is a view in which a part of the hydraulic system for operating the boom cylinder 7 is extracted. Fig. Fig. 4C is a view in which a part of the hydraulic system for operating the bucket cylinder 9 is extracted, and Fig. 4D is a view in which a part of the hydraulic system for operating the swing hydraulic motor 2A is extracted. Fig. 4E is a view in which a part of the hydraulic system for operating the left travel hydraulic motor 2ML is extracted, and Fig. 4F is a view in which part of the hydraulic system for operating the right travel hydraulic motor 2MR is extracted.

[0099] As in Fig. 4A to 4F, the hydraulic system includes the solenoid valve 31. The solenoid valve 31 includes the solenoid valve 31AL to the solenoid valve 31FL and the solenoid valve 31AR to the solenoid valve 31FR.

[0100] The solenoid valve 31 is arranged in a line connecting the pilot pump 15 and the pilot port of the corresponding control valve in the control valve group 17, and is configured to change the flow area of ​​the line by changing the opening area of ​​the solenoid valve 31. In the present embodiment, the solenoid valve 31 is a proportional solenoid valve and operates in response to control commands issued from 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 group 17 via the solenoid valve 31 in response to the operator's operation of the operating device 26 or independently of the operator's operation of the operating device 26.The controller 30 can cause the pilot pressure generated by the solenoid valve 31 to act on the pilot port of the corresponding control valve.

[0101] With this configuration, the controller 30 can operate the hydraulic actuator corresponding to the specific operating device 26 not only when the specific operating device 26 is operated, but also when the specific operating device 26 is not operated. Also, the controller 30 can forcibly stop the operation of the hydraulic actuator corresponding to the specific operating device 26 even when the specific operating device 26 is operated.

[0102] As in Fig. 4A, for example, the left operation lever 26L is used to operate the arm 5. Specifically, the left operation lever 26L uses the pilot oil discharged from the pilot pump 15 to apply a pilot pressure corresponding to an operation in the longitudinal direction to the pilot port of the control valve 176. Specifically, when the left operation lever 26L is operated in the arm closing direction (rearward direction), a pilot pressure corresponding to an operation amount is applied to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R. When the left operation lever 26L is operated in an arm opening direction (front direction), a pilot pressure corresponding to an operation amount is applied to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R.

[0103] The operating device 26 is provided with a switch SW. In the present embodiment, the switch SW includes a switch SW1 and a switch SW2. The switch SW1 is an MC switch (push-button switch) provided at the tip of the left operating lever 26L. The operator can operate the left operating lever 26L while pressing the switch SW1. The switch SW1 may be provided on the right operating lever 26R or at another location in the cab 10. The switch SW2 is the MC switch (push-button switch) located at the tip of the left travel lever 26DL. The operator can operate the left travel lever 26DL while pressing the switch SW2. The switch SW2 may be provided on the right travel lever 26DR or at another location in the cab 10.

[0104] The operation sensor 29LA detects the contents of the operator's operation of the left operation lever 26L in the longitudinal direction and outputs a detected value to the controller 30.

[0105] The solenoid valve 31AL operates in response to a control command (current command) issued by the controller 30. Then, the pilot pressure is adjusted by the pilot oil flowing from the pilot pump 15 to the right pilot port of the control valve 176L and to the left pilot port of the control valve 176R through the solenoid valve 31AL. The solenoid valve 31AR operates in response to a control command (current command) issued by the controller 30. Then, the pilot pressure is adjusted by the pilot oil flowing from the pilot pump 15 via the solenoid valve 31AR to the left pilot port of the control valve 176L and to the right pilot port of the control valve 176R. The solenoid valve 31AL can adjust the pilot pressure so that the control valve 176L and the control valve 176R can be set to the desired positions.Similarly, the solenoid valve 31AR can adjust the pilot pressure so that the control valve 176L and the control valve 176R can be adjusted to the desired positions.

[0106] In this configuration, the controller 30 can supply the pilot oil supplied from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the solenoid valve 31AL in response to the arm closing operation by the operator. The controller 30 can also supply the pilot oil supplied 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 arm closing operation by the operator. That is, the controller 30 can close the arm 5 in response to the arm closing operation by the operator or independently of the arm closing operation by the operator. As described above, the solenoid valve 31AL functions as the "arm solenoid valve" or the "arm closing solenoid valve."

[0107] Furthermore, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the solenoid valve 31AR in response to an arm-opening operation by the operator. 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 independently of the arm-opening operation by the operator. That is, the controller 30 can open the arm 5 in response to the arm-opening operation by the operator or independently of the arm-opening operation by the operator. Thus, the solenoid valve 31AR functions as the "arm solenoid valve" or the "arm-opening solenoid valve."

[0108] With this configuration, the controller 30 can lower the pilot pressure acting on the pilot port on the closing side of the control valve 176 (the left pilot port of the control valve 176L and the right pilot port of the control valve 176R) as needed to forcibly stop the closing operation of the arm 5 even when the arm closing operation is being performed by the operator. The same applies to the case where the opening operation of the arm 5 is forcibly stopped while the arm opening operation is being performed by the operator.

[0109] Alternatively, even if the operator closes the arm when the arm closing operation is performed by the operator, the controller 30 may forcibly stop the closing operation of the arm 5 by controlling the solenoid valve 31AR, increasing the pilot pressure acting on the pilot port on the opening side 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 opposite side of the pilot port on the closing side of the control valve 176, and forcibly returning the control valve 176 to the neutral position. The same applies to the case where the opening operation of the arm 5 is forcibly stopped when the arm opening operation is performed by the operator.

[0110] The same applies to the case where the operation of the boom 4 is forcibly stopped when the boom raising operation or a boom lowering operation is performed by the operator, to the case where the operation of the bucket 6 is forcibly stopped when a bucket closing operation or a bucket opening operation is performed by the operator, and to the case where the rotating operation of the upper swing body 3 is forcibly stopped when the rotating operation is performed by the operator, although the description thereof with reference to the following Fig. 4B to 4F are omitted. The same applies to the case where the travel operation of the lower traveling body 1 is forcibly stopped when the travel operation is performed by the operator.

[0111] To improve the responsiveness of the arm operation (arm closing operation and arm opening operation), the controller 30 may be configured to apply a small pilot pressure to the pilot ports on both sides of the control valve 176 before the arm operation is performed. The same applies to other operations, such as boom operation (boom raising operation and boom lowering operation). That is, the controller 30 may improve the responsiveness of the hydraulic actuators by using more pilot oil.

[0112] As in Fig. 4B, the right operation lever 26R is used to operate the boom 4. Specifically, the right operation lever 26R uses the pilot oil discharged from the pilot pump 15 to apply a pilot pressure corresponding to an operation in the longitudinal direction to the pilot port of the control valve 175. More specifically, when the right operation lever 26R is operated in a boom raising direction (rearward), a pilot pressure corresponding to an operation amount is applied to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R. When the right operation lever 26R is operated in a boom lowering direction (front direction), a pilot pressure corresponding to an operation amount is applied to the right pilot port of the control valve 175.

[0113] The operation sensor 29RA detects the contents of the operation of the right operation lever 26R in the longitudinal direction by the operator and outputs a detected value to the controller 30.

[0114] A solenoid valve 31BL operates in response to a control command (current command) issued by the controller 30. The pilot pressure is adjusted by pilot oil flowing from the pilot pump 15 via the solenoid valve 31BL to the right pilot port of the control valve 175L and to the left pilot port of the control valve 175R. The solenoid valve 31BR is actuated in response to a control command (current command) issued by the controller 30. Then, the pilot pressure is adjusted by the pilot oil flowing from the pilot pump 15 via the solenoid valve 31BR to the right pilot port of the control valve 175R. The solenoid valve 31BL can adjust the pilot pressure so that the control valve 175L and the control valve 175R can be adjusted to the desired positions. The solenoid valve 31BR can adjust the pilot pressure so that the control valve 175R can be adjusted to a desired position.

[0115] With this configuration, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the solenoid valve 31BL in response to the boom lifting operation by the operator. The controller 30 can also 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 by the operator. That is, the controller 30 can raise the boom 4 in response to the boom lifting operation by the operator or independently of the boom lifting operation by the operator. Thus, the solenoid valve 31BL functions as a "boom lifting solenoid valve" or a "boom lifting solenoid valve."

[0116] The controller 30 can also supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 175R via the solenoid valve 31BR in response to the operator's boom lowering operation. The controller 30 can also 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 independently of the operator's boom lowering operation. That is, the controller 30 can lower the boom 4 in response to the operator's boom lowering operation or independently of the operator's boom lowering operation. Thus, the solenoid valve 31BR functions as a "boom solenoid valve" or a "boom lowering solenoid valve."

[0117] As in Fig. 4C, the right operation lever 26R is also used to operate the bucket 6. Specifically, the right operation lever 26R uses the pilot oil discharged from the pilot pump 15 to apply a pilot pressure corresponding to the operation in the lateral direction to the pilot port of the control valve 174. Further specifically, when the right operation lever 26R is operated in a bucket closing direction (left direction), the pilot pressure corresponding to the operation amount is applied to the left pilot port of the control valve 174. When the right operation lever 26R is operated in a bucket opening direction (right direction), the pilot pressure corresponding to the operation amount is applied to the right pilot port of the control valve 174.

[0118] The operation sensor 29RB detects the contents of the operator's operation of the right operation lever 26R in the lateral direction and outputs a detected value to the controller 30. 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.

[0119] A solenoid valve 31CL operates in response to a control command (current command) issued by the controller 30. The solenoid valve 31CL adjusts the pilot pressure caused by the pilot oil flowing from the pilot pump 15 via the solenoid valve 31CL to the left pilot port of the control valve 174. A solenoid valve 31CR operates in response to a control command (current command) issued by the controller 30. The solenoid valve 31CR adjusts the pilot pressure caused by the pilot oil flowing from the pilot pump 15 via the solenoid valve 31CR to the right pilot port of the control valve 174. The solenoid valve 31CL can adjust the pilot pressure so that the control valve 174 can be adjusted to a desired valve position. Similarly, the solenoid valve 31CR can adjust the pilot pressure so that the control valve 174 can be set to a desired valve position.

[0120] With this configuration, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 174 via the solenoid valve 31CL in response to the bucket closing operation by the operator. Also, 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 independently of the bucket closing operation by the operator. That is, the controller 30 can close the bucket 6 in response to the bucket closing operation by the operator or independently of the bucket closing operation by the operator. Thus, the solenoid valve 31CL functions as a "bucket solenoid valve" or a "bucket closing solenoid valve."

[0121] Also, 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 in response to the bucket opening operation 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 174 via the solenoid valve 31CR, regardless of the bucket opening operation by the operator. That is, the controller 30 can open the bucket 6 in response to the bucket opening operation by the operator or independently of the bucket opening operation by the operator. Thus, the solenoid valve 31CR functions as a "bucket solenoid valve" or a "bucket opening solenoid valve."

[0122] Furthermore, as in Fig. 4D, the left operating lever 26L is also used to operate the rotating device 2. More specifically, the left operating lever 26L uses the pilot oil discharged from the pilot pump 15 to apply a pilot pressure corresponding to the operation in the lateral direction to the pilot port of the control valve 173. More specifically, when the left operating lever 26L is operated in a counterclockwise rotation direction (left direction), the left pilot port of the control valve 173 is operated with a pilot pressure corresponding to the operation amount. When the left operating lever 26L is operated in a clockwise rotation direction (right direction), the right pilot port of the control valve 173 is operated with a pilot pressure corresponding to the operation amount.

[0123] The operation sensor 29LB detects the contents of the left operation of the left operating lever 26L by the operator and outputs a detected value to the controller 30.

[0124] A solenoid valve 31DL operates in response to a control command (current command) issued by the controller 30. The pilot pressure is adjusted by the pilot oil flowing from the pilot pump 15 to the left pilot port of the control valve 173 through the solenoid valve 31DL. A solenoid valve 31DR operates in response to a control command (current command) issued by the controller 30. The pilot pressure is adjusted by the pilot oil flowing from the pilot pump 15 via the solenoid valve 31DR to the right pilot port of the control valve 173. The solenoid valve 31DL can adjust the pilot pressure so that the control valve 173 can be set to a desired valve position. Similarly, the solenoid valve 31DR can adjust the pilot pressure so that the control valve 173 can be set to a desired valve position.

[0125] With this configuration, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 173 via the solenoid valve 31DL in response to a counterclockwise rotation operation by the operator. The controller 30 can also 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 independently of the operator's counterclockwise rotation operation. That is, the controller 30 can rotate the rotating device 2 to the left in response to the operator's counterclockwise rotation operation or independently of the operator's counterclockwise rotation operation. In this way, the solenoid valve 31DL functions as a "rotary solenoid valve" or a "counterclockwise rotation solenoid valve."

[0126] The controller 30 can also supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 173 via the solenoid valve 31DR in response to a clockwise rotation operation by the operator. The controller 30 can also 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 independently of the operator's clockwise rotation operation. That is, the controller 30 can rotate the rotating device 2 to the right in response to the operator's clockwise rotation operation or independently of the operator's clockwise rotation operation. Thus, the solenoid valve 31DR functions as a "rotary solenoid valve" or a "right-turn solenoid valve."

[0127] As in Fig. 4E, the left travel lever 26DL is used to operate the left crawler. Specifically, the left travel lever 26DL uses the pilot oil discharged from the pilot pump 15 to apply a pilot pressure corresponding to an operation in the longitudinal direction to the pilot port of the control valve 171. More specifically, when the left travel lever 26DL is operated in the forward direction (front direction), the pilot pressure corresponding to an operation amount is applied to the left pilot port of the control valve 171. When the left travel lever 26DL is operated in the reverse direction (rear direction), the pilot pressure corresponding to an operation amount is applied to the right pilot port of the control valve 171.

[0128] The operation sensor 29DL electrically detects the contents of the operation of the left drive lever 26DL in the longitudinal direction by the operator and outputs a detected value to the controller 30.

[0129] A solenoid valve 31EL operates in response to a current command issued by the controller 30. The solenoid valve 31EL adjusts the pilot pressure caused by the pilot oil flowing from the pilot pump 15 via the solenoid valve 31EL to the left pilot port of the control valve 171. A solenoid valve 31ER operates in response to a current command issued by the controller 30. The solenoid valve 31ER adjusts the pilot pressure caused by the pilot oil flowing from the pilot pump 15 via the solenoid valve 31ER to the right pilot port of the control valve 171. The solenoid valves 31EL and 31ER can adjust the pilot pressure so that the control valve 171 can be set to a desired valve position.

[0130] With this configuration, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the left pilot port of the control valve 171 via the solenoid valve 31EL, regardless of the operator's left forward operation. That is, the left crawler 1CL can be moved forward. The controller 30 can also 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 operator's left reverse operation. That is, the left crawler 1CL can be moved backward. Thus, the solenoid valve 31EL functions as a "left travel solenoid valve" or a "left forward travel solenoid valve," and the solenoid valve 31ER functions as a "left travel solenoid valve" or a "left reverse solenoid valve."

[0131] As in Fig. 4F, the right travel lever 26DR is used to operate a right crawler. Specifically, the right travel lever 26DR uses the pilot oil discharged from the pilot pump 15 to apply a pilot pressure corresponding to an operation in the longitudinal direction to the pilot port of the control valve 172. More specifically, when the right travel lever 26DR is operated in the forward direction, a pilot pressure corresponding to an operation amount is applied to the right pilot port of the control valve 172. When the right travel lever 26DR is operated in the reverse direction (rear direction), a pilot pressure corresponding to an operation amount is applied to the left pilot port of the control valve 172.

[0132] The operation sensor 29DR electrically detects the contents of the operation of the right drive lever 26DR in the longitudinal direction by the operator and outputs the detected value to the controller 30.

[0133] Solenoid valve 31FL operates in response to a current command issued by controller 30. Solenoid valve 31FL adjusts the pilot pressure caused by the pilot oil flowing from pilot pump 15 to the left pilot port of control valve 172 via solenoid valve 31FL. Solenoid valve 31FR operates in response to a current command issued by controller 30. Solenoid valve 31FR adjusts the pilot pressure caused by the pilot oil flowing from pilot pump 15 to the right pilot port of control valve 172 via solenoid valve 31FR. Solenoid valves 31FL and 31FR can adjust the pilot pressure so that control valve 172 can be adjusted to a desired valve position.

[0134] With this configuration, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the right pilot port of the control valve 172 via the solenoid valve 31FR regardless of the operator's right forward operation. That is, the right crawler 1CR can be moved forward. The controller 30 can also supply the pilot oil discharged from the pilot pump 15 via the solenoid valve 31FL to the left pilot port of the control valve 172 regardless of the operator's right reverse operation. That is, the right crawler 1CR can be moved backward. Thus, the solenoid valve 31FR functions as a "right travel solenoid valve" or the "right forward travel solenoid valve," and the solenoid valve 31FL functions as the "right travel solenoid valve" or the "right reverse travel solenoid valve."

[0135] The excavator 100 may also have a configuration for automatic operation of the bucket tilt mechanism. In this case, the hydraulic system part related to a bucket tilt cylinder included in the bucket tilt mechanism may be configured in the same way as the hydraulic system part related to the operation of the boom cylinder 7.

[0136] Although the electric operating lever is described as an example of the operating device 26, a hydraulic operating lever may also be used instead of the electric operating lever. In this case, furthermore, an operation amount of the hydraulic operating lever may be detected in the form of pressure by a pressure sensor and input to the controller 30. The solenoid valve may be arranged between the operating device 26 as the hydraulic operating lever and the pilot port of each control valve. The solenoid valve is configured to operate in response to an electrical signal from the controller 30. With this configuration, the operating device 26 can move each control valve by increasing or decreasing the pilot pressure according to an operation amount when a manual operation is performed using the operating device 26 as the hydraulic operating lever.Each control valve may be configured as a solenoid spool valve. In this case, the solenoid spool valve is actuated in response to an electrical signal from the controller 30 according to the amount of operation of the electric operating lever.

[0137] Next, the flow of a loading operation by the excavator 100 will be described with reference to Fig. 5 described. Fig. Figure 5 is a diagram explaining the loading process of the excavator 100.

[0138] Figures (A) to (D) in Fig. 5 are used to describe a sequence of the excavation process. A period of time during which the excavation operation is carried out is called an excavation operation period. The excavation process is divided into a first half of the excavation process as shown in (A) and (B) in Fig. 5, and a second half of the excavation process as shown in (C) and (D) in Fig. 5 shown, divided.

[0139] As in (A) in Fig. 5, the operator of the excavator 100 moves the tip of the bucket 6 so that the tip of the bucket 6 is at a desired height position with respect to an excavation target (in this example, soil and sand), and closes the arm 5 from an open state as shown in (A) in Fig. 5 until the position of the arm 5 becomes substantially perpendicular to the ground, as shown in (B) in Fig. 5. Through this operation, the earth and sand are excavated to a certain depth, and the earth and sand are raked until the arm 5 is substantially perpendicular to the ground surface. The above-described operation is referred to as the first half of the excavation operation, and a period thereof is referred to as a first-half period of the excavation operation.

[0140] Then, as in (C) in Fig. 5, the operator closes the arm 5 further and rakes the earth and sand further with the shovel 6. Then, as shown in (D) in Fig. 5, the bucket 6 until an upper edge thereof becomes substantially horizontal, and receives the raked earth and sand into the bucket 6. Further, the operator raises the boom 4 and raises the bucket 6 to a position shown in (D) in Fig. 5. The above operations are referred to as the second half of the dredging operation, and a period thereof is referred to as the second half of the dredging operation. The time period shown in (C) in Fig. 5 may be a combined operation of the arm 5 and the bucket 6 or a combined operation of the boom 4, the arm 5 and the bucket 6.

[0141] Next, the operator raises the boom 4 keeping the upper edge of the bucket 6 substantially horizontal until a bottom of the bucket 6 reaches a desired height above the ground, as shown in (E) in Fig. 5. The desired height is, for example, not less than the height of a dump truck tailgate. After or simultaneously with this operation, the operator rotates the upper pivot body 3 as indicated by an arrow to bring the bucket 6 into a position for unloading (tipping) soil and sand.

[0142] When a boom lifting and rotating operation is completed, the operator opens the arm 5 and the bucket 6 as shown in (F) in Fig. 5 to discharge (dump) soil and sand in the bucket 6 onto the dump truck bed, the ground, or the like. In this discharge of soil and sand (dumping operation), the operator can only open the bucket 6 to discharge soil and sand, or he can open the arm 5 and bucket 6 to discharge soil and sand while lowering the boom 4.

[0143] When the unloading operation is finished, the operator rotates the upper rotating body 3 as shown by an arrow in (G) in Fig. 5 to move the bucket 6 directly above the excavation position. After that, the operator lowers the bucket 6 to a desired height as shown in (A) in Fig. 5 to repeat the excavation operation. The operator can lower the boom 4 to lower the bucket 6 to a desired height above the excavation target simultaneously with rotation.

[0144] In this way, the controller 30 continues the loading operation of the excavator 100, repeating a cycle (series of operations) including the “excavation operation,” the “boom raising and rotating operation,” the “unloading operation,” and the “boom lowering and rotating operation.”

[0145] Next, with reference to Fig. 6, an example of a processing flow (hereinafter referred to as “setting processing”) for setting a target value by the controller 30 is described. Fig. 6 is a flowchart showing an example of the flow of setting processing. In the illustrated example, the target specifier 56 of the controller 30 executes setting processing each time the excavation operation is completed until the target value is set. Specifically, the target specifier 56 determines whether the excavation operation is completed or not based on the outputs of the position sensor and the cylinder pressure sensor. The target specifier 56 executes the setting process when it determines that the excavation operation is completed.

[0146] First, the target specifier 56 determines whether a predetermined excavation operation has been performed (step ST1). In the illustrated example, the target specifier 56 determines whether the amount of soil and sand held in the bucket 6 is greater than a predetermined amount based on an image of the bucket 6 lifted in the air after the excavation operation, taken by the camera S6F. Then, the target specifier 56 determines that the predetermined excavation operation has been performed if it can be determined that the amount of soil and sand held in the bucket 6 is greater than the predetermined amount. For example, the target specifier 56 determines that the predetermined excavation operation has been performed if it can be determined that the bucket 6 is full of soil and sand.In contrast, the target specifier 56 determines that the predetermined excavation operation has not been performed if it cannot be determined that the amount of soil and sand accommodated in the bucket 6 is greater than a predetermined amount, that is, if it can be determined that the bucket 6 is not full of soil and sand. Note that even if it can be determined that the bucket 6 is full of soil and sand, the target specifier 56 can determine that the predetermined excavation operation has not been performed if it determines that the amount of soil and sand spilled from the bucket 6 when the bucket 6 is lifted is greater than a predetermined amount.

[0147] The destination specifier 56 can determine that the predetermined excavation operation has been performed when a predetermined button is pressed. The predetermined button is a button pressed by the operator when the operator visually observes the interior of the bucket 6 raised in the air after the excavation operation and determines that the bucket 6 is filled with soil and sand. The operator can determine whether the bucket 6 is filled with soil and sand or not by viewing the image captured by the camera S6F. In this case, the image captured by the camera S6F can be displayed on the display device 40.

[0148] When it is determined that the predetermined excavation operation has not been performed (NO in step ST1), the target specifier 56 ends the current setting processing without setting a target value.

[0149] Conversely, if it is determined that the predetermined excavation operation has been performed (YES in step ST1), the target specifier 56 sets a target value (step ST2). In the illustrated example, the target specifier 56 sets, as a target value, a maximum value of the excavation reaction force calculated during the execution of the excavation operation determined as the predetermined excavation operation. The target specifier 56 may set, as a target value, 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 as the predetermined excavation operation. In this case, the target value is used for comparison with the horizontal component or the vertical component of the excavation reaction force calculated during the subsequently performed excavation operation.

[0150] Next, with reference to Fig. 7 describes an example of a processing flow (hereinafter referred to as “support processing”) in which the controller 30 supports the excavation process. Fig. 7 is a flowchart showing an example of a flow of the assistance processing. In the illustrated example, the excavation assistance part 57 repeatedly performs the control 30 of the assistance processing during the excavation operation in a predetermined control cycle. More specifically, the excavation assistance part 57 determines whether or not an excavation operation is being performed based on outputs of the position sensor and the cylinder pressure sensor. More specifically, the excavation assistance part 57 determines that the excavation operation is started when the excavation reaction force repeatedly calculated by the excavation reaction force calculator 55 in the predetermined control cycle exceeds a predetermined start determination value.After determining that the excavation operation has started, the excavation support part 57 determines that the excavation operation has ended when the excavation reaction force repeatedly calculated by the excavation reaction force calculator 55 in the predetermined control cycle falls below a predetermined final determination value. Each of the start determination value and the final determination value is determined in accordance with the posture of the extension piece. The excavation support part 57 repeatedly executes this support processing from the time it determines that the excavation operation has started until the time it determines that the excavation operation has ended. The excavation support part 57 can 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 calculator 55 in a predetermined control cycle.In this case, the start determination value and the end determination value are each a value corresponding to the magnitude of the horizontal component or the vertical component of the excavation reaction force.

[0151] First, the excavation support part 57 determines whether the excavation reaction force has reached a target value (step ST11). In the illustrated example, the excavation support part 57 determines whether the excavation reaction force calculated by the excavation reaction force calculator 55 has reached a target value set by the target specifier 56. If the target specifier 56 has not yet set the target value, that is, if the target value remains at an initial value (a maximum value that the excavation reaction force can assume), the excavation support part 57 determines that the excavation reaction force has not reached the target value. The excavation support part 57 may be configured not to execute the support processing until the target value is set.

[0152] If it is determined that the excavation reaction force has reached the target value (YES in step ST11), the excavation support part 57 executes an excavation support function (step ST12). In the illustrated example, the excavation support function is a function that notifies the operator of the excavator 100 that the excavation reaction force has reached the target value. Specifically, the excavation support part 57 outputs a control command to the display device 40 to cause the display device 40 to display image information indicating 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 indicating that the excavation reaction force has reached the target value.The information indicating that the excavation reaction force has reached the target value may be, for example, information instructing the start of the boom lifting operation. By obtaining such information, the operator of the excavator 100 can start the boom lifting operation at an appropriate time. As a result, the operator can, for example, achieve a state where the bucket 6 is fully loaded with soil and sand at the end of each excavation operation. That is, the controller 30 can achieve an excavation amount without excess or deficiency in each excavation operation, and thus, the working efficiency of the excavator 100 can be improved.

[0153] In contrast, when it is determined that the excavation reaction force has not reached the target value (NO in step ST11), the excavation support part 57 ends the current support processing without performing the excavation support function.

[0154] The excavation support part 57 may be configured to perform another excavation support function when it is determined that the excavation reaction force has not reached the target value. The another excavation support function is, for example, a machine guidance function or a machine control function. Specifically, the excavation support part 57 may be configured to automatically operate at least one of the boom cylinder 7 and the bucket cylinder 9 so that the control point set at the tip of the bucket 6 moves horizontally toward the upper swing body 3 when the arm closing operation is performed with the MC switch pressed. With this configuration, the operator of the excavator 100 can perform the excavation operation by moving the tip of the bucket 6 horizontally to approach the excavator 100 while the tip of the bucket 6 is at a desired depth below the ground.Then, when the operator is informed that the excavation reaction force has reached the target value, the operator performs the boom lifting operation to achieve the excavation amount without excess or shortage.

[0155] Next, another example of the setting processing flow will be explained with reference to Fig. 8 and Fig. 9 described. Fig. 8 is a flowchart showing another example of the setting processing flow. Fig. Figure 9 is a diagram showing the excavator 100 digging a furrow GR. In particular, the left figures (upper left, middle left and lower left figures) of Fig. 9 cross-sectional views of the soil to be excavated, and the right figure of Fig. Figure 9 is a plan view of the excavator 100 digging the furrow GR. The upper left figure of Fig. 9 shows a state in which the second half of the first excavation process is started, the middle left figure of Fig. 9 shows a state in which the second half of the second excavation process is started, and the lower left figure of Fig. 9 shows a state in which the second half of a third excavation operation is started.

[0156] In the Fig. 8 and Fig. In the example shown in Figure 9, the target specifier 56 of the controller 30 performs setting processing each time the excavation operation is completed until the target value is set. Specifically, the target specifier 56 determines whether the excavation operation is completed or not based on the outputs of the position sensor and the cylinder pressure sensor. The target specifier 56 performs setting processing when it determines that the excavation operation is completed.

[0157] In the Fig. 8 and Fig. 9, the operator of the excavator 100 unloads the excavated earth and sand DS (see the right figure in Fig. 9) on the soil surface around the furrow GR while digging the furrow GR with the predetermined soil depth DP (see the left figure in Fig. 9). For illustration, the right figure of Fig. 9 Soil and sand DS1 excavated and removed by the first excavation process, soil and sand DS2 excavated and removed by the second excavation process, and soil and sand DS3 excavated and removed by the third excavation process. As shown in the left figures of Fig. As shown in Figure 9, the operator of the excavator 100 excavates the trench GR during each excavation operation while bringing the tip of the bucket 6 to a predetermined soil depth DP and moving the bucket 6 horizontally by a desired excavation length along the longitudinal direction (X-axis direction) of the trench GR. That is, the operator can excavate the trench GR while moving the tip of the bucket 6 in substantially the same path (when parallel displacement) during each excavation operation, and can increase or decrease the weight of the excavated earth and sand during each excavation operation by lengthening or shortening the excavation length. This means that when the excavation length is the same, the weight of the excavated earth and sand is substantially the same. The operator can also perform the traveling operation of the lower traveling body 1 at a time between the previous excavation operation and the current excavation operation. In the right figure of Fig. 9, for the purpose of explanation, positions of the front end portions of the lower traveling body 1 when the first excavation operation is performed are shown by a dot-dash line, positions of the front end portions of the lower traveling body 1 when the second excavation operation is performed are shown by a dashed line, and the lower traveling body 1 when the third excavation operation is performed is shown by a solid line.

[0158] First, the target specifier 56 determines whether the predetermined excavation operation has been performed or not (step ST21). The determination by the target specifier 56 is the same as the determination by the target specifier 56 in step ST1 of Fig. 6. The target specifier 56 can determine whether the predetermined excavation operation has been performed or not based on a transition of the excavation reaction force calculated during the execution of the current excavation operation and the amount of soil and sand taken into the bucket 6 by the current excavation operation. The same applies to step ST1 in Fig. 6.

[0159] When it is determined that the predetermined excavation operation has not been performed (NO in step ST21), the target specifier 56 ends the current setting processing without setting a target value.

[0160] Conversely, if it is determined that the predetermined excavation operation has been performed (YES in step ST21), the target specifier 56 determines a relationship between the excavation reaction force and the excavation weight (step ST22). In the illustrated example, the target specifier 56 creates a reference table in which the values ​​of the plurality of excavation reaction forces are linked to the values ​​of the plurality of excavation weights in a one-to-one relationship based on a maximum value of the excavation reaction force calculated during the execution of the excavation operation determined as the predetermined excavation operation and a calculated value of the weight (excavation weight) of the earth and sand taken into the bucket 6 by the excavation operation. In this case, the number of times of the excavation operation determined to be the predetermined excavation operation is preferably two or more times.The values ​​of the multiple excavation reaction forces can be values ​​of the horizontal component or the vertical component of the multiple excavation reaction forces.

[0161] Next, the target specifier 56 sets a target value (step ST23). In the example shown, the target specifier 56 derives the excavation reaction force value corresponding to the desired excavation weight value from the reference table generated in step ST22 and sets the excavation reaction force value as a target value. The desired excavation weight value may be a value preset by the operator of the excavator 100 or may be a value automatically calculated based on various types of information.

[0162] In the Fig. 8 and Fig. In the example shown in Figure 9, the target specifier 56 obtains the relationship between the excavation reaction force and the excavation weight based on information obtained during an excavation operation performed at the same construction site on the same day, and then sets the target value. However, the target specifier 56 may obtain the relationship between the excavation reaction force and the excavation weight based on information obtained during an excavation operation at the same construction site on a different day, and then sets a target value. Alternatively, the target specifier 56 may obtain the relationship between the excavation reaction force and the excavation weight based on information obtained during an excavation operation at a different construction site, and then sets a target value.

[0163] Next, another example of the setting processing flow will be explained with reference to Fig. 10 and Fig. 11 described. Fig. 10 is a flowchart showing another example of the setting processing flow. Fig. 11 is a plan view of the excavator 100 for digging the furrow GR and loading the excavated earth and sand onto a loading bed CB of a dump truck 200. In particular, Fig. 11 is a diagram showing the conditions of the excavator 100 and the dump truck 200 during the unloading process after a fourth excavation process. In Fig. 11 shows soil and sand LS being loaded onto the loading area CB of the dump truck 200 by the loading process, which includes four excavations. In Fig. 11, the state of the excavator 100 after completion of the fourth excavation process is shown by a dashed line. An excavation process of the furrow GR in the Fig. The example shown in Figure 11 is the same as the one in Fig. 9 described procedures.

[0164] In the Fig. 10 and Fig. In the examples shown in FIG. 11, the target specifier 56 of the controller 30 performs the setting processing each time the excavation operation is completed until a target value is set. Specifically, the target specifier 56 determines whether the excavation operation is completed or not based on outputs from the position sensor and the cylinder pressure sensor. The target specifier 56 performs the setting processing when it determines that the excavation operation is completed. Fig. In the example shown in Fig. 10, the excavated earth and sand are loaded onto the bed CB of the dump truck 200 while the excavator 100 excavates the furrow GR to a predetermined soil depth DP. The maximum loading capacity of the dump truck 200 is 10 tons. In each excavation operation, the operator of the excavator 100 causes the tip of the bucket 6 to reach the predetermined soil depth DP and excavates the furrow GR while moving the bucket 6 horizontally by a desired excavation length along the longitudinal direction of the furrow GR. That is, in the first half of each excavation operation, the operator can excavate the furrow GR while moving the tip of the bucket 6 in substantially the same path in each excavation operation, and can increase or decrease the weight of the earth and sand excavated in each excavation operation by lengthening or shortening the excavation length.The operator can also perform a travel operation with the lower traveling body 1 at a time between the previous excavation operation and the current excavation operation.

[0165] First, the target specifier 56 determines whether a predetermined excavation operation has been performed or not (step ST31). The determination by the target specifier 56 is the same as the determination by the target specifier 56 in step ST21 of Fig. 8.

[0166] When it is determined that the predetermined excavation operation has not been performed (NO in step ST31), the target specifier 56 ends the current setting processing without setting a target value.

[0167] In contrast, if it is determined that the predetermined excavation operation has been performed (YES in step ST31), the target specifier 56 detects the relationship between the excavation reaction force and the excavation weight (step ST32). The detection by the target specifier 56 is the same as the detection by the target specifier 56 in step ST22 of Fig. 8.

[0168] Next, the target specifier 56 obtains a target weight (step ST33). In the illustrated example, the target specifier 56 recognizes the maximum loading capacity of the dump truck 200 based on the image of the dump truck 200 captured by the camera S6F as a space recognition device, and determines the maximum loading capacity as the target weight. Specifically, the target specifier 56 recognizes the maximum loading capacity of the dump truck 200 by recognizing the size of a license plate, the size of the vehicle body, the height of the bed CB, a numerical value displayed on a maximum loading capacity sticker, or the like using image recognition technology. The target specifier 56 can receive information (maximum loading capacity information) transmitted from the dump truck 200 via the communicator T1 and obtain the maximum loading capacity as the target weight.The target weight may be a value entered via the input device 42.

[0169] Next, the target specifier 56 sets a target value (step ST34). In the illustrated example, the target specifier 56 sets a target value based on the relationship between the excavation reaction force and the excavation weight obtained in step ST32 and the target weight obtained in step ST33.

[0170] For example, if 1.0 ton of soil and sand is loaded onto the bed CB of the dump truck 200 by the first excavation operation (first excavation operation) performed before setting the target value, the target specifier 56 determines that the bed CB of the dump truck 200 can be fully loaded by the following nine excavations (second excavation operation). This is because 9.0 tons remain until the maximum loading amount of 10.0 tons is reached, and it can be estimated that 1.0 ton of soil and sand can be loaded onto the bed CB with one excavation operation. That is, the target specifier 56 can derive a value (10 times) obtained by rounding up a quotient of the maximum loading amount (10.0 tons) and the excavated weight (1.0 ton) by the first excavation operation as the number of excavations required to reach the target weight.The first excavation is the excavation performed before setting the target value, and the second excavation is the excavation performed after setting the target value. In this case, the target specifier 56 sets the maximum value of the excavation reaction force (maximum excavation reaction force) during the first excavation as the target value for each of the excavations from the second to the tenth. In each of the excavations from the second to the tenth, excavation is performed with the excavation reaction force of the same magnitude as that of the first excavation, and thus, the excavation weight (1.0 ton) of the same order of magnitude as that of the first excavation is achieved. In this case, the weight of the earth and sand loaded onto the dump truck 200 by the 10 excavations is 10.0 tons, as given by 1.0 ton × 10 times.The weight of soil and sand already loaded onto the bed CB of the dump truck 200 by the first excavation (the first excavation) before the target value is set is the excavation weight of the first excavation (1.0 tons) and is also called a "cumulative weight." The weight of soil and sand loaded onto the bed CB of the dump truck 200 by the second excavation (the excavations from the second to the tenth) after the target value is set is a value (9.0 tons) obtained by subtracting the cumulative weight from the maximum loading amount and is also called a "residual weight."

[0171] As described above, the target specifier 56 may set the target value so that the maximum excavation reaction force corresponding to the maximum excavation reaction force when performing the first excavation operation is achieved in the second excavation operation. Specifically, the target specifier 56 may set a target value so that soil and sand with the weight obtained by subtracting the cumulative weight from the target weight can be loaded onto the loading bed CB by the number of second excavations obtained by subtracting the number of first excavations already performed from the number of required operations. The target specifier 56 may set a target value so that the weight of soil and sand loaded onto the loading bed CB every second excavation operation is substantially equal to the excavation weight during the first excavation operation.With this configuration, the target specifier 56 can operate the excavator 100 so that the excavation weight is substantially the same during each excavation operation.

[0172] Alternatively, the target specifier 56 may determine that the bed CB of the dump truck 200 can be fully loaded in the following eight excavations (second excavation) if 1.2 tons of soil and sand are loaded onto the bed CB of the dump truck 200 by the first excavation (first excavation) performed before the target value is set. In this case, the target specifier 56 may set the maximum excavation reaction force during the first excavation as the target value for each of the second to eighth excavations. In this way, in each of the second to eighth excavations, excavation is performed with the same excavation reaction force of the same magnitude as that of the first excavation, and the same excavation weight (1.2 tons) as that of the first excavation is achieved.The target specifier 56 may set, as a target value for the ninth excavation, a value corresponding to 1 / 3 of the maximum excavation reaction force of the first excavation. In the ninth excavation, excavation is performed with an excavation reaction force of 1 / 3 of that of the first excavation, and the excavation weight (0.6 tons) of 1 / 3 of that of the first excavation is achieved. That is, when the first excavation is completed, the target specifier 56 deduces that the remaining required number of times is nine. The remaining weight, that is, the weight of the earth and sand loaded onto the loading platform CB eight times in the second excavation, is 8.8 tons in total, including 1.2 tons × seven times and 0.4 tons × once.The remaining weight, together with the cumulative weight (1.2 tons × 1 times) corresponding to the weight loaded onto the loading platform CB by the first excavation operation, gives the target weight (10.0 tons).

[0173] Thus, the target specifier 56 can set the target value so that a maximum excavation reaction force equal to the maximum excavation reaction force when performing the first excavation operation and a maximum excavation reaction force smaller than the maximum excavation reaction force are selectively realized in the second excavation operation. Specifically, the target specifier 56 can set the target value so that the earth and sand with the weight resulting from subtracting the cumulative weight from the target weight can be loaded onto the loading bed CB by the second excavation operation the number of times resulting from subtracting the number of times the first excavation operations have already been performed from the required number of times. The target specifier 56 can set the target value so that the excavation weight of as many times as possible becomes substantially equal to the excavation weight of the first excavation operation.With this configuration, the target specifier 56 can operate the excavator 100 so that the excavation weight in the second excavation operation becomes substantially equal to the excavation weight of the first excavation operation as many times as possible. Subsequently, the target specifier 56 can operate the excavator 100 so that the amount of soil and sand corresponding to the target weight is loaded onto the loading bed CB.

[0174] Alternatively, the target specifier 56 may determine that if 1.2 tons of earth and sand are loaded onto the bed CB of the dump truck 200 by the first excavation operation (first excavation operation) performed before setting the target value, the bed CB of the dump truck 200 can be fully loaded by the following eight excavations (second excavation operation). In this case, the target specifier 56 may set a value corresponding to approximately 92% of the maximum excavation reaction force during the first excavation operation as the target value for each of the second to ninth excavations. In each of the second to ninth excavations, excavation is performed with an excavation reaction force having a magnitude of approximately 92% of that during the first excavation operation, and an excavation weight (1.1 tons) approximately 92% of that during the first excavation operation is achieved.That is, when the first excavation is completed, the target specifier 56 deduces that the required number of times is nine. The remaining weight, that is, the weight of the earth and sand loaded eight times onto the loading bed CB in the second excavation, is 8.8 tons, which is 1.1 tons × eight times. The remaining weight, together with the cumulative weight (1.2 tons × 1 time), that is, the weight loaded once onto the loading bed CB in the first excavation, results in the target weight (10.0 tons).

[0175] Thus, the target specifier 56 may set the target value so that the maximum excavation reaction force, which is smaller than the maximum excavation reaction force when performing the first excavation, is achieved every second excavation. Specifically, the target specifier 56 may set the target value so that the earth and sand with the weight obtained by subtracting the cumulative weight from the target weight can be loaded onto the loading bed CB by the second excavation the number of times obtained by subtracting the number of times the first excavation has already been performed from the required number of times. Then, the target specifier 56 may set the target value so that the weight of the earth and sand loaded onto the loading bed CB each time by the second excavation becomes substantially the same.With this configuration, the target specifier 56 can operate the excavator 100 so that the excavation weight becomes substantially the same each time during the second excavation. Then, the target specifier 56 can operate the excavator 100 so that the soil and sand corresponding to the target weight are loaded onto the loading bed CB.

[0176] Alternatively, the target specifier 56 may determine that the bed CB of the dump truck 200 can be fully loaded by the subsequent seven excavations (second excavation) if an average of 1.0 ton of soil and sand is loaded onto the bed CB of the dump truck 200 by each of the three excavations (first excavation) performed before the target value is set. In this case, the target specifier 56 may set, as the target value for each of the fourth to tenth excavations, a value corresponding to the maximum average excavation reaction force of the three excavations.In each of the fourth to tenth excavations, excavation is performed with the excavation reaction force equal to the maximum average excavation reaction force in the first three excavations, and the excavation weight (1.0 ton) equal to the average excavation weight in the first three excavations is achieved. That is, when the third excavation is completed, the target specifier 56 derives that the remaining required number of times is eight. The remaining weight, that is, the weight of the earth and sand loaded onto the loading bed CB by the seven excavations of the second excavation, is then 7.0 ton, as given by 1.0 ton × 7 times. The remaining weight becomes the target weight (10.0 ton) together with the cumulative weight (3.0 ton) equal to the weight loaded onto the loading bed CB in the three times of the first excavation.

[0177] As described above, the target specifier 56 may set the target value so that the maximum excavation reaction force, which is smaller than the maximum average excavation reaction force of the plurality of first excavations, is achieved every second excavation. Specifically, the target specifier 56 may set the target value so that the earth and sand with the weight obtained by subtracting the cumulative weight from the target weight can be loaded onto the loading bed CB with the number of second excavations obtained by subtracting the number of first excavations already performed from the required number of times. The target value may be set by the target specifier 56 so that the weight of the earth and sand loaded onto the loading bed CB every second excavation is substantially equal to the average excavation weight during the first excavation.With this configuration, the target specifier 56 can operate the excavator 100 such that the excavated weight during every second excavation is substantially equal to the average excavated weight during the first excavation. Subsequently, the target specifier 56 can operate the excavator 100 such that the amount of soil and sand corresponding to the target weight is loaded onto the loading bed CB.

[0178] In the above example, the target specifier 56 detects the relationship between the excavation reaction force and the excavation weight as a linear relationship, but the relationship between the excavation reaction force and the excavation weight may also be detected as a nonlinear relationship.

[0179] In the above example, the target specifier 56 sets a value equal to or smaller than the excavation weight in a first excavation as the target value, but a value larger than the excavation weight in a first excavation may be set as the target value.

[0180] As described above and in Fig. 1, the excavator 100 according to the embodiment of the present disclosure includes the lower traveling body 1, the upper swing body 3 swingably attached to the lower traveling body 1, the extension piece AT attached to the upper swing body 3, and the controller 30 serving as a control device for repeatedly calculating the excavation reaction force based on information related to the excavation operation performed by the extension piece AT with respect to the construction object at the construction site. The controller 30 sets a target value based on the excavation reaction force calculated during an excavation operation performed one or more times, and assists each excavation operation performed after the target value related to the excavation reaction force is set based on the target value related to the excavation reaction force.

[0181] The excavation operation performed one or more times to set the target value is an excavation operation for detecting the properties of the soil to be excavated or the like (hardness, viscosity, density, or relationship between excavation amount and excavation reaction force, etc.), and may be an excavation operation performed in response to the operator's manual operation of the operation device 26, excavation operations performed while being assisted by the machine guidance function or the machine control function, or excavation operations performed automatically regardless of the operation of the operation device 26.

[0182] The excavation operation performed one or more times to set the target value may be an excavation operation for a test excavation performed first at a construction site, an excavation operation performed on the first of each day at a construction site, or an excavation operation performed whenever the characteristics of the excavated object change due to rainfall or the like. Therefore, the target value may be configured so that the operator can reset it by pressing a predetermined switch.

[0183] With this configuration, the controller 30 can increase the working efficiency of the excavator 100. This is because the operator of the excavator 100 can adjust the excavation amount achieved in each excavation operation to a desired excavation amount. That is, the operator of the excavator 100 can, for example, achieve a state where the bucket 6 is filled with soil and sand immediately after each excavation operation.

[0184] The controller 30 may be configured to determine whether or not a predetermined excavation operation suitable for calculating the target value has been performed based on information about the excavation operation performed by the attachment AT for the construction object at the construction site, and to set the target value based on the excavation reaction force calculated during the excavation operation determined as the predetermined excavation operation.

[0185] In the above example, the controller 30 determines whether the desired excavation amount has been reached or not based on an image of the bucket 6 captured by the camera S6F immediately after the excavation operation. If it is determined that the desired excavation amount has been reached, it determines that the predetermined excavation operation has been performed. The controller 30 then sets the maximum value of the excavation reaction force calculated during the excavation operation determined as the predetermined excavation operation as the target value.

[0186] With this configuration, the controller 30 can support the operation of the operator of the excavator 100 so that the maximum value of the excavation reaction force in each excavation operation after setting the target value is equal to the maximum value of the excavation reaction force in each excavation operation before setting the target value. Therefore, the controller 30 can prevent the excavation amount from being excessively varied due to each excavation operation after setting the target value. As a result, the controller 30 can improve the working efficiency of the excavator 100.

[0187] 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 performed after the target value is set.

[0188] With this configuration, the operator of the excavator 100 can achieve a desired excavation amount by performing the boom lifting operation when receiving the notification that the current excavation reaction force has reached the target value in each excavation operation.

[0189] The controller 30 may be configured to automatically operate a predetermined actuator when the current excavation reaction force has reached the target value in each excavation operation performed after the target value is set.

[0190] With this configuration, the operator of the excavator 100 can achieve a desired excavation amount by simply performing an arm closing operation without worrying about the timing of the boom raising operation.

[0191] During each excavation operation performed after setting the target value, the controller 30 may be configured to automatically operate a predetermined actuator so that a point set at a predetermined portion of the extension piece moves linearly until the current excavation reaction force reaches the target value.

[0192] With this configuration, the operator of the excavator 100 can perform the excavation operation by, for example, simply closing the arm while pressing the MC switch after penetrating the tip of the bucket 6 to the desired soil depth and moving the tip horizontally to approach the excavator 100 until the current excavation reaction force reaches the target value. When the current excavation reaction force reaches the target value, the excavation assist function is executed as described above, allowing the operator to achieve the desired excavation amount.

[0193] As in Fig. 5, the excavator 100 according to the embodiment of the present disclosure is an excavator for moving (loading) an object, such as earth and sand, to a predetermined location, such as the bed CB of the dump truck 200 or the ground, by repeating a series of operations including the excavation operation and the unloading operation, and includes the lower traveling body 1, the upper swing body 3 swingably mounted on the lower traveling body 1, the attachment AT attached to the upper swing body 3, a sensor attached to the upper swing body 3, and the controller 30 serving as a controller for calculating an excavation reaction force generated by the excavation operation and an excavation weight (loading weight), which is the weight of the object accommodated in the bucket 6 and moved (loaded) to the predetermined location, based on the output of the sensor.The excavation weight is also referred to as "movement weight." The controller 30 sets a target value related to the excavation reaction force during the second excavation operation, which is subsequently performed one or more times, based on the relationship between the excavation reaction force calculated during the first excavations performed one or more times and the excavation weight. The sensor includes at least one of a position sensor, a cylinder pressure sensor, and a space detection device. The first excavation operation is performed before the target value is set, and the second excavation operation is performed after the target value is set.

[0194] This configuration allows the weight of the object moved to the predetermined location to be calculated more accurately. For example, with this configuration, the excavation weight can be derived more accurately than in a case where the correspondence relationship between the excavation reaction force and the moved weight (excavation weight or loading weight) is not used. This is because the excavation reaction force is not affected by disturbances generated when the bucket 6 is lifted in the air.

[0195] This configuration also achieves the effect of controlling the weight (moving weight) of objects such as soil and sand that are moved to the predetermined location every second excavation performed after setting the target value. Therefore, this configuration can suppress the moved weight from varying significantly every second excavation.

[0196] The excavator 100 operates so that the weight of the object moved to the predetermined location becomes the target weight by repeating a series of operations including the excavation operation and the unloading operation. The controller 30 may be configured to set a target value related to the excavation reaction force during the second excavation operation based on the relationship between the excavation reaction force and the excavation weight calculated during the first excavation operation, the cumulative weight, which is the weight of the object already moved to the predetermined location, and the target weight.

[0197] This configuration produces an effect that the moved weight can be controlled every second excavation operation so that the moved weight in the second excavation operation, which is carried out one or more times after setting the target value, does not exceed the residual weight resulting from the difference between the target weight and the cumulative weight.

[0198] Furthermore, the controller 30 may be configured to calculate the number of excavation operations (required number of times) required for the weight of an object moved to a predetermined location to reach the target weight based on the relationship between the excavation reaction force and the excavation weight calculated during the first excavation operation, the cumulative weight, and the target weight, and to set a target value related to the excavation reaction force during the second excavation operation based on the number of excavation operations.

[0199] This configuration achieves an effect that the moved weight can be controlled every second excavation so that the moved weight in the second excavation, which is subsequently performed one or more times after the target value is set, becomes the weight obtained by dividing the remaining weight by the required number of times. Therefore, this configuration can prevent the moved weight from becoming excessively large or small by the second excavation of a certain time, and thus can improve the fuel efficiency of the excavator 100.

[0200] As in Fig.5, the excavator 100 according to the embodiment of the present disclosure is an excavator that operates so that the weight of an object, such as earth and sand, moved to a predetermined location such as the bed CB of the dump truck 200 or the ground becomes the target weight by repeating a series of operations including the excavation operation and the unloading operation, and is provided with the lower traveling body 1, the upper swing body 3 swingably attached to the lower traveling body 1, the attachment AT attached to the upper swing body 3, a sensor attached to the upper swing body 3, and the controller 30 serving as a controller for calculating the excavation reaction force generated by the excavation operation and the excavation weight as the weight of the object accommodated in the bucket 6 based on the output of the sensor.The controller 30 sets a target value with respect to the excavation reaction force during the second excavation operation, which is subsequently performed one or more times, based on the relationship between the excavation reaction force and the excavation weight calculated during the first excavation operation, which is performed one or more times, and the target weight.

[0201] This configuration makes it easy to align the weight of the object moved to the predetermined location and the target weight. This is because the target value related to the excavation reaction force is set so that the weight of the object moved to the predetermined location and the target weight coincide with each other when the maximum excavation reaction force corresponding to the target value is reached every other excavation process.

[0202] If the excavation reaction force or excavation weight calculated during the first excavation operation is an abnormal value, the controller 30 may be configured to set a target value related to the excavation reaction force during the second excavation operation based on a relationship between the excavation reaction force and the excavation weight calculated during the excavation operation performed one or more times before the first excavation operation and the target weight. The excavation reaction force is determined to be an abnormal value if, for example, it exceeds a range between a preset upper limit and a preset lower limit. The same applies to the excavation weight.In this case, for example, when it is determined that the excavation reaction force calculated during the third first excavation operation among the three first excavation operations is an abnormal value, the controller 30 sets a target value related to the excavation reaction force during the second excavation operation based on the relationship between the excavation reaction force and the excavation weight calculated during the first and second first excavation operations and the target weight.

[0203] With this configuration, setting a target value based on an abnormal value can be suppressed. Therefore, this configuration has the effect of more accurately calculating the weight of the object being moved to a predetermined location.

[0204] The controller 30 may be configured to notify the operator that the current excavation reaction force has reached the target value every other excavation operation performed after setting the target value. For example, the controller 30 may notify the operator that the current excavation reaction force has reached the target value via the display device 40, the sound output device 43, or the like. In this case, the operator, who recognizes that the current excavation reaction force has reached the target value, performs the boom raising operation at that time to raise the boom 4 and lift the bucket 6, which is at least partially underground, into the air, thereby achieving the excavation weight (loading weight) corresponding to the target excavation reaction force value.

[0205] Therefore, this configuration achieves an effect that the weight of the object moved to a predetermined location and the target weight can be easily reconciled. This is because, for the excavation weight, if the boom lifting operation is performed while generating the excavation reaction force corresponding to the target value, the excavation weight (target excavation weight) corresponding to the target value (excavation reaction force) is achieved every other excavation operation, and the difference between the target excavation weight and the actual excavation weight increases when the excavation reaction force deviates from the target value when performing the boom lifting operation.

[0206] Furthermore, the controller 30 may be configured to automatically actuate a predetermined actuator when the current excavation reaction force reaches the target value every other excavation operation performed after setting the target value. For example, the controller 30 (automation controller 54) may automatically adjust the pilot pressure acting on the pilot port of the control valve corresponding to the boom cylinder 7. Thus, the controller 30 (automation controller 54) can raise the boom 4 and lift the bucket 6, which is at least partially underground, into the air, thereby achieving the excavation weight (loading weight) corresponding to the excavation reaction force target value.

[0207] Therefore, this arrangement brings about the effect that the weight of the object moved to a predetermined location can be more easily aligned with the target weight. This is because the boom 4 can be raised at a more appropriate time than when the boom lifting operation is performed manually.

[0208] The preferred embodiment of the present invention has been described in detail. However, the present invention is not limited to the above-described embodiment or the following embodiment. Various variations, substitutions, and the like can be applied to the above-described or following embodiment without departing from the scope of the present invention. Also, the separately described features can be combined as long as no technical conflict arises.

[0209] For example, the excavator 100 may be a remote-controlled excavator. In this case, the controller 30 may be a controller installed in a remote control room located outside the excavator 100. The excavator 100 may be an autonomous excavator that does not require operator control. LIST OF REFERENCE SYMBOLS

[0210] 1...Lower Travel Body, 2...Rotating Device, 2A...Swing Hydraulic Motor, 2M...Travel Hydraulic Motor, 2ML...Left Travel Hydraulic Motor, 2MR...Right Travel Hydraulic Motor, 3...Upper Swing Body, 4...Boom, 5...Arm, 6...Bucket, 7...Boom Cylinder, 8...Arm Cylinder, 9...Bucket Cylinder, 10...Cabin, 11...Engine, 13...Governor, 14...Main Pump, 15...Pilot Pump, 17...Control Valve Group, 18L...Left Throttle, 18R...Right Throttle, 19L...Left Control Pressure Sensor, 19R...Right Control Pressure Sensor, 26...Control Device, 26D...Travel Control Device, 26DL...Left Travel Lever, 26DR...Right Travel Lever, 26L...Left Control Lever, 26R...Right operating lever, 28...Discharge pressure sensor, 29, 29DL, 29DR, 29LA, 29LB, 29RA, 29RB...Operation sensor, 30...Control, 31, 31AL to 31FL, 31AR to 31FR...Solenoid valve, 40...Display device, 42...Input device, 42a...Mode switch, 43...Sound output device, 47...Memory device, 50...Machine guide part, 51...Position calculator, 52...Distance calculator, 53...Information transmitter, 54...Automation controller, 55...Excavation reaction force calculator, 56...Target specifier, 57...Excavation support part, 100...Excavator, 171 to 176...Control valve, 200...Dump truck, AT...Attachment, CB...Loading area, DP...Soil depth, DS, DS1, DS2, DS3...Earth and sand, GR...Furrow, LS...Earth and sand, Q1...Positioning device, S1...Boom angle sensor, S2...Arm angle sensor, S3...Bucket angle sensor, S4...Machine body tilt sensor, S5...Rotation state sensor, S6...Imaging device, S6B, S6F, S6L, S6R...Camera, S7B...Boom ground pressure sensor, S7R...Boom rod pressure sensor, S8B...Arm ground pressure sensor, S8R...arm rod pressure sensor, S9B...bucket bottom pressure sensor, S9R...bucket rod pressure sensor, SW, SW1, SW2...switch, T1...communicator. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2020-165260

[0003]

Claims

[1] An excavator for moving an object to a predetermined location by repeating a series of operations including an excavation operation and an unloading operation, the excavator comprising: a lower chassis; an upper pivoting body pivotally mounted on the lower traveling body; an extension piece attached to the upper pivot body; a sensor attached to the upper swivel body and a control device configured to calculate, based on an output of the sensor, an excavation reaction force generated by the excavation operation and an excavation weight, which is a weight of an object picked up in a bucket and moved to the predetermined location, wherein the control device is further configured to set a target value related to the excavation reaction force of a second excavation operation subsequently performed one or more times, based on a relationship between the excavation reaction force calculated during a first excavation operation performed one or more times and the excavation weight. [2] Excavator according to claim 1, wherein the excavator is configured to operate so that the weight of the object moved to the predetermined location becomes a target weight by repeating the series of operations including the excavation operation and an unloading operation, and the control device is further configured to set the target value related to the excavation reaction force during the second excavation operation based on a relationship between the excavation reaction force and the excavation weight calculated during the first excavation operation, a cumulative weight that is the weight of the object that has already been moved to the predetermined location, and the target weight. [3] Excavator according to claim 2, wherein the control device is further configured to calculate a number of excavation times necessary for the weight of the object moved to the predetermined location to reach the target weight, based on the relationship between the excavation reaction force and the excavation weight calculated during the first excavation, the cumulative weight, and the target weight, and set the target value of the excavation reaction force during the second excavation operation based on the number of excavation operation times. [4] An excavator that operates to make a weight of an object moved to a predetermined location a target weight by repeating a series of operations including an excavation operation and an unloading operation, the excavator comprising: a lower chassis; an upper pivoting body pivotally mounted on the lower traveling body; an extension piece attached to the upper pivot body; a sensor attached to the upper swivel body and a control device configured to calculate, based on an output of the sensor, an excavation reaction force generated by the excavation operation and an excavation weight, which is a weight of an object picked up in a bucket and moved to the predetermined location, wherein the control device is further configured to set a target value related to an excavation reaction force during a second excavation operation subsequently performed one or more times, based on a relationship between the excavation reaction force and the excavation weight calculated during a first excavation operation performed one or more times and the target weight. [5] The excavator according to claim 4, wherein the control device is further configured to set the target value with respect to the excavation reaction force during the second excavation operation based on the relationship between the excavation reaction force and the excavation weight calculated during the excavation operation performed one or more times before the first excavation operation and the target weight, in a case where the excavation reaction force or the excavation weight calculated during the first excavation operation is an abnormal value. [6] The excavator according to any one of claims 1 to 5, wherein in each of the second excavation operations, each being the second excavation operation performed after the target value is set, the control device is further configured to notify an operator that a current excavation reaction force has reached the target value. [7] An excavator according to any one of claims 1 to 5, wherein in each of the second excavation operations performed after the target value is set, the control device is further configured to automatically operate a predetermined actuator when a current excavator reaction force reaches the target value.

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