Shovel and control device

Abstract

This disclosure provides an excavator that can suppress a decrease in work efficiency even when the excavation reaction force is large. [Solution] The shovel 100 comprises a lower traveling body 1, an upper rotating body 3 rotatably mounted on the lower traveling body 1, an attachment AT attached to the upper rotating body 3, and a control device that controls the operation of the attachment AT. The attachment AT includes a boom 4 rotatably supported on the upper rotating body 3, an arm 5 rotatably supported on the boom 4, and a bucket 6 rotatably supported on the arm 5. When the control device detects that the digging operation of the attachment AT has stopped due to a digging reaction force from the digging target EO, it causes the bucket 6 to close.

Description

Technical Field

[0001] The present disclosure relates to an excavator and a control device.

Background Art

[0002] Conventionally, a hydraulic excavator has been known (see Patent Document 1 below). The hydraulic excavator described in Patent Document 1 has a boom, a stick, and a bucket, a revolving body that supports the boom, and a traveling body that mounts the revolving body thereon and travels on the ground.

[0003] This conventional hydraulic excavator has a device that measures the magnitude of the excavation reaction force received by the bucket from the ground when the bucket advances into the ground during excavation so as to excavate the ground. Further, this conventional hydraulic excavator has a control device that changes the turning angle of the boom according to the magnitude of the measured excavation reaction force, and if the measured excavation reaction force is large, deflects the boom upward in the advancing direction of the bucket.

[0004] According to this conventional hydraulic excavator, if the measured excavation force is large, the boom deflects the bucket upward in the advancing direction so as to reduce the excavation depth into the ground according to the magnitude of the excavation reaction force and reduce the excavation force. Thereby, the advancing speed and excavation force of the bucket do not unnecessarily decrease, and while maintaining a large excavation force, the rotation speed of the bucket and stick is not excessively decreased by the excavation force, and the excavation speed is maintained high.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the conventional hydraulic excavator described in Patent Document 1 above, when the excavation reaction force is large, the control device changes the swing angle of the boom and deflects the direction of travel of the bucket upward, which may reduce the amount of soil and other materials scooped up by the bucket and decrease work efficiency.

[0007] This disclosure provides an excavator and control device that can suppress a decrease in work efficiency even when the excavation reaction force is large. [Means for solving the problem]

[0008] One aspect of the present disclosure provides an excavator comprising: a lower traveling body; an upper rotating body rotatably mounted on the lower traveling body; an attachment including a boom rotatably supported on the upper rotating body, an arm rotatably supported on the boom, and a bucket rotatably supported on the arm; and a control device for controlling the operation of the attachment, wherein the control device closes the bucket when it detects a stopped state in which the excavation operation of the attachment has stopped due to an excavation reaction force from the object to be excavated.

[0009] Another aspect of the present disclosure provides a control device for controlling the operation of an attachment of an excavator, the attachment comprising a lower traveling body, an upper slewing body rotatably mounted on the lower traveling body, and an attachment including a boom rotatably supported on the upper slewing body, an arm rotatably supported on the boom, and a bucket rotatably supported on the arm, wherein the control device causes the bucket to close when a stopped state is detected in which the excavation operation of the attachment has stopped due to an excavation reaction force from the object to be excavated. [Effects of the Invention]

[0010] According to each of the above embodiments of this disclosure, it is possible to provide a shovel and a control device that can suppress a decrease in work efficiency even when the excavation reaction force is large. [Brief explanation of the drawing]

[0011] [Figure 1] This is a side view showing an embodiment of the excavator according to this disclosure. [Figure 2] Figure 1 is a block diagram showing an example of the configuration of an excavator. [Figure 3] Figure 1 is a diagram showing the configuration of the hydraulic system installed in the excavator. [Figure 4] Figure 1 is a flowchart showing an example of the operation of the control device mounted on the excavator. [Figure 5] Figure 1 is a process diagram showing the excavation operation and bucket closing operation of the shovel. [Figure 6] This is a flowchart showing another example of operation of the control device mounted on the excavator in Figure 1. [Figure 7] Figure 1 is a process diagram showing the excavation operation and boom raising operation of the shovel. [Figure 8] This is a schematic diagram showing an embodiment of the control device for an excavator according to this disclosure. [Modes for carrying out the invention]

[0012] Embodiments of this disclosure will be described below with reference to the drawings. The embodiments described below are illustrative and do not limit the invention. Not all features and combinations thereof in the embodiments of this disclosure are necessarily essential to the invention. In each drawing, the same or corresponding components are denoted by the same or corresponding reference numerals, and redundant descriptions may be omitted.

[0013] First, an embodiment of the excavator according to the present disclosure will be described with reference to Figures 1 to 3. Figure 1 is a side view showing an embodiment of the excavator according to the present disclosure. As shown in Figure 1, the excavator 100 comprises a lower traveling body 1, an upper rotating body 3, an attachment AT, and a controller 30.

[0014] The lower traveling body 1 includes, for example, a crawler that is driven by a traveling hydraulic motor 2M to move the excavator 100. Specifically, the lower traveling body 1 includes a left crawler driven by a left traveling hydraulic motor 2ML shown in FIG. 2 and a right crawler driven by a right traveling hydraulic motor 2MR shown in FIG. 2. Note that the excavator 100 may be a wheel-type hydraulic excavator in which the lower traveling body 1 has tires.

[0015] The upper slewing body 3 is provided on the lower traveling body 1 so as to be slewing capable. Specifically, the upper slewing body 3 is slewing-capably attached onto the lower traveling body 1 via a slewing mechanism 2. The slewing mechanism 2 is driven by a slewing hydraulic motor 2A shown in FIG. 2 to slew the upper slewing body 3 on the lower traveling body 1. The slewing hydraulic motor 2A is a slewing actuator mounted on the upper slewing body 3 to drive the slewing mechanism 2. Note that the slewing actuator may be an electric actuator.

[0016] On the front left side of the upper slewing body 3, a cabin 10 as an operator cab for the excavator 100 is provided. Inside the cabin 10, in addition to a controller 30, an operating device 26 shown in FIG. 2 and the like are provided. Further, on the upper slewing body 3, in addition to the slewing hydraulic motor 2A, a power source such as an engine 11 is mounted. Further, an external recognition device 70 is attached to the upper slewing body 3.

[0017] The external recognition device 70 is configured to recognize objects around the excavator 100. The external recognition device 70 may be configured to calculate the distance to the recognized object. The external recognition device 70 includes, for example, an imaging device, LiDAR, millimeter-wave radar, ultrasonic sensor, infrared sensor, or any combination thereof. The external recognition device 70 includes, for example, a front recognition device 70F, a rear recognition device 70B, a left recognition device 70L, and a right recognition device (not shown).

[0018] The front recognition device 70F is attached, for example, to the upper front part of the cab 10 and recognizes an object in front of the excavator 100. The rear recognition device 70B is attached to the rear part of the upper swing body 3 and recognizes an object behind the excavator 100. The left recognition device 70L is attached to the left side part of the upper swing body 3 and recognizes an object to the left of the excavator 100. The right recognition device is attached to the right side part of the upper swing body 3 and recognizes an object to the right of the excavator 100. These external recognition devices 70 are arranged such that a part of the object detection range of adjacent external recognition devices 70 overlaps, and are configured to recognize an object existing in 360 degrees around the excavator 100.

[0019] In addition, the front, rear, left, and right directions in the excavator 100 are the directions as seen from the operator boarding the cab 10. FIG. 1 shows a three-dimensional orthogonal coordinate system in which the front direction, rear direction, left direction, right direction, upward direction, and downward direction of the excavator 100 are the positive X-axis direction, negative X-axis direction, positive Y-axis direction, negative Y-axis direction, positive Z-axis direction, and negative Z-axis direction, respectively.

[0020] The attachment AT is provided adjacent to the right side of the cab 10 at the center of the front part of the upper swing body 3. The attachment AT includes a boom 4, an arm 5, and a bucket 6. The boom 4 is rotatably supported by the upper swing body 3 via a boom foot pin. The arm 5 is rotatably supported by the boom 4 via a boom top pin. The bucket 6 is rotatably supported by the arm 5 via a bucket pin.

[0021] The boom 4 is driven by a boom cylinder 7 to rotate up and down. Specifically, the boom cylinder 7 performs a boom raising operation of extending the piston rod to rotate the boom 4 upward, and a boom lowering operation of contracting the piston rod to rotate the boom 4 downward.

[0022] The arm 5 is driven by the arm cylinder 8 to open and close relative to the boom 4. Specifically, the arm cylinder 8 extends the piston rod to perform an arm closing operation, closing the arm 5 relative to the boom 4, and retracts the piston rod to perform an arm opening operation, opening the arm 5 relative to the boom 4.

[0023] The bucket 6 is driven by a bucket cylinder 9 connected via a linkage mechanism to open and close relative to the arm 5. Specifically, the bucket cylinder 9 performs a bucket closing operation by extending its piston rod to close the bucket 6 relative to the arm 5, and a bucket opening operation by retracting its piston rod to open the bucket 6 relative to the arm 5.

[0024] Bucket 6 is an end attachment for excavation that is attached to the tip of attachment AT. The end attachment is not limited to bucket 6, and may be other types of buckets, such as a large bucket, a slope bucket, or a dredging bucket. Bucket 6 may also be provided with a bucket tilt mechanism.

[0025] The controller 30 (an example of a control device) is installed, for example, inside the cabin 10 and controls the drive of the shovel 100. The functions of the controller 30 may be realized by any hardware, software, or a combination thereof. For example, the controller 30 is mainly composed of a microcomputer including a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), a non-volatile auxiliary storage medium, and various input / output interfaces. The controller 30 realizes various functions by executing various programs stored in the ROM or non-volatile auxiliary storage medium with the CPU.

[0026] Figure 2 is a block diagram showing an example of the configuration of excavator 100 in Figure 1. In Figure 2, double lines indicate the transmission of mechanical power, and solid lines indicate the high-pressure hydraulic path. Dashed lines indicate the transmission path of pilot pressure, and dotted lines indicate the transmission paths of electrical signals and control signals.

[0027] Excavator 100 is equipped with a hydraulic drive system that drives hydraulic actuators including a boom cylinder 7, an arm cylinder 8, a bucket cylinder 9, a slewing hydraulic motor 2A, a left travel hydraulic motor 2ML, and a right travel hydraulic motor 2MR. The hydraulic drive system of excavator 100 includes, for example, an engine 11, a regulator 13, a main pump 14, a pilot pump 15, and a control valve unit 17.

[0028] The engine 11 is the main power source in the hydraulic drive system and is mounted, for example, at the rear of the upper slewing body 3. Specifically, the engine 11 rotates at a constant speed at a preset target rotational speed under direct or indirect control by the controller 30 (described later) and drives the main pump 14 and the pilot pump 15. The power source of the shovel 100 may be a combination of a power source such as a battery or fuel cell and an electric motor. The engine 11 is, for example, a diesel engine that uses light oil as fuel. The engine 11 may also be a gasoline engine or a hydrogen engine, etc.

[0029] The regulator 13 controls the discharge rate of the main pump 14. For example, the regulator 13 adjusts the angle (tilt angle) of the swash plate of the main pump 14 in response to a control command from the controller 30.

[0030] The main pump 14 (an example of a hydraulic pump) is mounted at the rear of the upper slewing body 3, similar to the engine 11, and supplies hydraulic fluid to the control valve unit 17 through the high-pressure hydraulic line 16. The main pump 14 is driven by the engine 11, as described above. The main pump 14 is, for example, a variable displacement hydraulic pump. As described above, under the control of the controller 30, the piston stroke length of the main pump 14 can be adjusted by adjusting the tilt angle of the swash plate by the regulator 13, thereby controlling the discharge flow rate (discharge pressure).

[0031] The pilot pump 15 is an example of a pilot pressure generating device and is configured to supply hydraulic fluid to hydraulic control equipment via a pilot line. In this embodiment, the pilot pump 15 is a fixed-displacement hydraulic pump. The pilot pressure generating device may also be implemented by the main pump 14. That is, the main pump 14 may have the function of supplying hydraulic fluid to the control valve unit 17 via a hydraulic fluid line, as well as the function of supplying hydraulic fluid to various hydraulic control equipment via a pilot line. In this case, the pilot pump 15 may be omitted.

[0032] The control valve unit 17 is a hydraulic control device that controls the hydraulic system in the excavator 100. In this embodiment, the control valve unit 17 includes control valves 171 to 176. The control valve unit 17 is configured to selectively supply the hydraulic fluid discharged by the main pump 14 to one or more hydraulic actuators through the control valves 171 to 176.

[0033] Control valves 171 to 176 control, for example, the flow rate of hydraulic fluid from the main pump 14 to the hydraulic actuator, and the flow rate of hydraulic fluid from the hydraulic actuator to the hydraulic fluid tank. More specifically, control valve 171 corresponds to the left travel hydraulic motor 2ML, control valve 172 to the right travel hydraulic motor 2MR, and control valve 173 to the swing hydraulic motor 2A. In addition, control valve 174 corresponds to the bucket cylinder 9, control valve 175 to the boom cylinder 7, and control valve 176 to the arm cylinder 8.

[0034] The operating system of the shovel 100 according to this embodiment includes, for example, an operating device 26, a discharge pressure sensor 28, an operating sensor 29, and a controller 30.

[0035] The operating device 26 is a device used by the operator to operate the actuator. The operating device 26 includes, for example, an operating lever and an operating pedal. The actuator includes at least one of a hydraulic actuator and an electric actuator.

[0036] The discharge pressure sensor 28 is configured to detect the discharge pressure of the main pump 14. In this embodiment, the discharge pressure sensor 28 outputs the detected value to the controller 30.

[0037] The operation sensor 29 is configured to detect the operator's actions using the operation device 26. In this embodiment, the operation sensor 29 detects the operating direction and amount of operation of the operation device 26 corresponding to each actuator, and outputs the detected values ​​to the controller 30.

[0038] The controller 30 controls the opening area of ​​the proportional valve 31 according to the output of the operation sensor 29. The controller 30 then supplies the hydraulic fluid discharged by the pilot pump 15 to the pilot port of the corresponding control valve in the control valve unit 17. The pressure of the hydraulic fluid supplied to each pilot port (pilot pressure) is, in principle, the pressure corresponding to the operating direction and amount of the operating device 26 corresponding to each hydraulic actuator. In this way, the operating device 26 is configured to supply the hydraulic fluid discharged by the pilot pump 15 to the pilot port of the corresponding control valve in the control valve unit 17.

[0039] The control system of the excavator 100 according to this embodiment includes a controller 30, a display device D1, an input device D2, and a communication device T1. The control system of the excavator 100 also includes, as a configuration related to the semi-automatic operation function, a proportional valve 31, a boom angle sensor S1, an arm angle sensor S2, a bucket angle sensor S3, a machine body tilt sensor S4, a slewing angle sensor S5, an imaging device S6, and a positioning device PS.

[0040] The controller 30 sets a target rotational speed based on the operator's actions, for example, and performs drive control to keep the engine 11 rotating at a constant speed. The controller 30 also outputs control commands to the regulator 13 as needed to change the discharge amount of the main pump 14. The controller 30 controls the regulator 13 based on the detected pilot pressure values ​​corresponding to the operating states of various operating elements (i.e., various hydraulic actuators) in the operating device 26, which are input from the operation sensor 29, and adjusts the discharge amount of the main pump 14. The controller 30 also performs control related to a machine guidance function that guides the operator's manual operation of the shovel 100 through the operating device 26. The controller 30 also performs control related to a machine control function that automatically assists the operator's manual operation of the shovel 100 through the operating device 26.

[0041] Furthermore, the controller 30 includes, for example, an excavation motion generation unit 301, a stop state detection unit 302, and an excavation completion determination unit 303 that control the operation of attachment AT to automatically support the excavation work of the shovel 100. These excavation motion generation unit 301, stop state detection unit 302, and excavation completion determination unit 303 represent functions of the controller 30 that are realized by executing various programs stored in ROM or non-volatile auxiliary storage media that constitute the controller 30 on the CPU. In addition, the excavation motion generation unit 301, stop state detection unit 302, and excavation completion determination unit 303 may be realized by, for example, any hardware, software, or a combination thereof.

[0042] The display device D1 is installed in a location easily visible to a seated operator inside the cabin 10 and displays various information images under the control of the controller 30. The display device D1 may be connected to the controller 30 via an in-vehicle communication network such as CAN (Controller Area Network), or it may be connected to the controller 30 via a one-to-one dedicated line. Furthermore, the display device D1 is not limited to a device pre-installed in the cabin 10, but may be a separately installed monitor. Moreover, the display device D1 can be any device capable of displaying information; for example, a tablet terminal capable of communicating with the communication device T1 may be used.

[0043] The input device D2 is located within reach of a seated operator in the cabin 10 and receives various operation inputs from the operator, outputting signals corresponding to the operation inputs to the controller 30. The input device D2 includes a touch panel mounted on the display of the display device D1 which displays various information images, a knob switch located at the tip of the lever device of the operation device 26, and button switches, levers, toggles, rotary dials, etc., installed around the display device D1. Signals corresponding to the operations performed on the input device D2 are received by the controller 30.

[0044] The communication device T1 communicates with external devices through a predetermined network, including a mobile communication network with a base station as its endpoint, a satellite communication network, and the Internet network. The communication device T1 is, for example, a mobile communication module that supports mobile communication standards such as LTE (Long Term Evolution), 4G (4th Generation), and 5G (5th Generation), or a satellite communication module for connecting to a satellite communication network.

[0045] The proportional valve 31 functions as a control valve for machine control. The proportional valve 31 is located in the pipeline connecting the pilot pump 15 and the pilot port of the control valve in the control valve unit 17, and is configured to change the flow area of ​​the pipeline. In this embodiment, the proportional valve 31 operates in response to control commands output by the controller 30. Therefore, the controller 30 can supply the hydraulic fluid discharged by the pilot pump 15 to the pilot port of the control valve in the control valve unit 17 via the proportional valve 31, independently of the operator's operation of the operating device 26.

[0046] This configuration allows the controller 30 to operate the hydraulic actuator corresponding to a specific operating device 26 even when no operation is being performed on that specific operating device 26. Furthermore, if the excavator 100 does not have machine control or remote control functions, the excavator 100 does not need to have a proportional valve 31.

[0047] The boom angle sensor S1 detects the rotation angle of the boom 4. In this embodiment, the boom angle sensor S1 is an acceleration sensor attached to the boom 4 and can detect the boom angle, which is the rotation angle of the boom 4 relative to the upper slewing body 3. The boom angle is smallest when the boom 4 is lowered to its lowest position, and increases as the boom 4 is raised. The detection signal corresponding to the boom angle from the boom angle sensor S1 is input to the controller 30.

[0048] The arm angle sensor S2 detects the rotation angle of the arm 5. In this embodiment, the arm angle sensor S2 is an acceleration sensor attached to the arm 5 and can detect the arm angle, which is the rotation angle of the arm 5 relative to the boom 4. The arm angle is smallest when the arm 5 is closed to its shortest extent, and increases as the arm 5 is opened. The detection signal corresponding to the arm angle from the arm angle sensor S2 is input to the controller 30.

[0049] The bucket angle sensor S3 detects the rotation angle of the bucket 6. In this embodiment, the bucket angle sensor S3 is an acceleration sensor attached to the link mechanism that drives the bucket 6, and can detect the bucket angle, which is the rotation angle of the bucket 6 relative to the arm 5. The bucket angle is smallest when the bucket 6 is closed to its fullest extent, and increases as the bucket 6 is opened. The detection signal corresponding to the bucket angle from the bucket angle sensor S3 is input to the controller 30.

[0050] The boom angle sensor S1, arm angle sensor S2, and bucket angle sensor S3 may be a potentiometer using a variable resistor, a stroke sensor that detects the stroke amount of the corresponding hydraulic cylinder, or a rotary encoder that detects the rotation angle around the connecting pin. The boom angle sensor S1, arm angle sensor S2, and bucket angle sensor S3 constitute an attitude sensor that detects the attitude of the excavation attachment.

[0051] The machine body tilt sensor S4 is attached to the upper rotating body 3 and is configured to detect the tilt of the upper rotating body 3 with respect to a predetermined plane. In this embodiment, the machine body tilt sensor S4 is an acceleration sensor that detects the tilt angle of the upper rotating body 3 around the longitudinal axis and the tilt angle around the left-right axis with respect to the horizontal plane. The longitudinal axis and left-right axis of the upper rotating body 3 are, for example, orthogonal to each other and pass through the shovel center point, which is a point on the rotation axis of the shovel 100.

[0052] The rotation angle sensor S5 is attached to the upper rotating body 3 and is configured to detect the rotational angular velocity of the upper rotating body 3. In this embodiment, the rotation angle sensor S5 is a gyro sensor. The rotation angle sensor S5 may also be a resolver or a rotary encoder, etc. The rotation angle sensor S5 may also detect the rotational speed. The rotational speed may be calculated from the rotational angular velocity.

[0053] Furthermore, if the aircraft tilt sensor S4 includes a gyro sensor, a 6-axis sensor, an IMU, etc., capable of detecting angular velocity around three axes, the rotation state of the upper rotating body 3 (for example, rotational angular velocity) may be detected based on the detection signal from the aircraft tilt sensor S4. In this case, the rotational angle sensor S5 may be omitted.

[0054] The imaging device S6 is an example of the external environment recognition device 70 shown in Figure 1. The imaging device S6 recognizes objects around the shovel 100 by capturing images of objects present around the shovel 100. The imaging device S6 includes, for example, a front camera as a front recognition device 70F, a rear camera as a rear recognition device 70B, a left camera as a left recognition device 70L, and a right camera as a right recognition device.

[0055] The positioning device PS is configured to acquire information regarding the position of the shovel 100. In this embodiment, the positioning device PS is configured to measure the position and orientation of the shovel 100. Specifically, the positioning device PS is a GNSS receiver incorporating an electronic compass, which measures the latitude, longitude, and altitude of the current position of the shovel 100, as well as the orientation of the shovel 100.

[0056] The shovel 100 operates actuators (e.g., hydraulic actuators) in response to the operation of the operator sitting in the cabin 10, driving the moving elements (hereinafter referred to as "driven elements") such as the lower traveling body 1, the upper slewing body 3, the boom 4, the arm 5, and the bucket 6.

[0057] Furthermore, instead of being configured to be operable by the operator in the cabin 10, or in addition to being configured to be operable by the operator in the cabin 10, the shovel 100 may also be configured to be remotely operated from outside the shovel 100. When the shovel 100 is remotely operated, the inside of the cabin 10 may be unoccupied.

[0058] Furthermore, the shovel 100 may automatically operate its actuators regardless of the operator's actions. As a result, the controller 30 of the shovel 100 has the function of automatically operating at least some of the multiple actuators that operate each of the driven elements such as the lower traveling body 1, the upper slewing body 3, the boom 4, the arm 5, and the bucket 6, that is, a so-called "automatic driving function" or "machine control function".

[0059] The automatic driving function may include a function that automatically operates driven elements (actuators) other than the target driven element (actuator) in response to the operator's operation of the control device 26 or remote control, i.e., a so-called "semi-automatic driving function" or "operation-assist type machine control function". The automatic driving function may also include a function that automatically operates at least some of the multiple driven elements (hydraulic actuators) on the premise that there is no operation of the operator's control device 26 or remote control, i.e., a so-called "fully automatic driving function" or "fully automatic machine control function". In the case of the excavator 100, when the fully automatic driving function is enabled, the interior of the cabin 10 may be unoccupied. Furthermore, the semi-automatic driving function and fully automatic driving function may include a mode in which the operation content of the driven elements (actuators) that are the target of automatic driving is automatically determined according to predetermined rules. Furthermore, semi-autonomous driving functions and fully autonomous driving functions may include a mode in which the shovel 100 autonomously makes various decisions, and the operation of the driven elements (hydraulic actuators) that are subject to autonomous driving is determined autonomously in accordance with the results of those decisions (so-called "autonomous driving function").

[0060] Specifically, when the arm 5 is operated by the operator via the operating device 26, the controller 30 may automatically operate at least one of the boom 4 and the bucket 6 so that the tip position of the bucket 6 coincides with a predetermined target construction surface. In addition, the controller 30 may also automatically operate the arm 5 regardless of the operating state of the operating device 26 that operates the arm 5. In other words, the controller 30 may trigger the operation of the operating device 26 by the operator to perform predetermined operations on the attachment. Hereinafter, the function of the controller 30 that operates not only the arm 5 but also at least one of the boom 4 and the bucket 6 in response to the operation of the operating device 26 corresponding to the arm 5 will be referred to as the "semi-automatic operation function". The semi-automatic operation function may be executed, for example, by operating a predetermined switch (hereinafter referred to as the "MC (Machine Control) switch") located at the tip of any of the lever devices included in the operating device 26. In this embodiment, a paddle switch may be used as the MC switch, in which the machine control function is executed while it is pressed.

[0061] Furthermore, some of the functions of controller 30 may be implemented by other controllers (control devices). In other words, the functions of controller 30 may be implemented in a manner distributed among multiple controllers. For example, machine guidance functions and machine control functions may be implemented by dedicated controllers (control devices).

[0062] Next, with reference to Figure 3, an example of the configuration of the hydraulic system mounted on the excavator 100 according to this embodiment will be described. Figure 3 is a diagram showing an example of the configuration of the hydraulic system mounted on the excavator 100 according to this embodiment. In Figure 3, the mechanical power transmission system, hydraulic fluid line, pilot line, and electrical control system are shown by double lines, solid lines, dashed lines, and dotted lines, respectively.

[0063] The hydraulic system of the Shovel 100 mainly includes an engine 11, a regulator 13, a main pump 14, a pilot pump 15, a control valve unit 17, an operating device 26, a discharge pressure sensor 28, an operating sensor 29, and a controller 30, etc.

[0064] In Figure 3, the hydraulic system is configured to circulate hydraulic fluid from the main pump 14, driven by the engine 11, to the hydraulic fluid tank via the center bypass pipeline 40 or the parallel pipeline 42.

[0065] The engine 11 is the power source for the shovel 100. In this embodiment, the engine 11 is, for example, a diesel engine that operates to maintain a predetermined rotational speed. The output shaft of the engine 11 is connected to the input shafts of the main pump 14 and the pilot pump 15, respectively.

[0066] The main pump 14 is configured to supply hydraulic fluid to the control valve unit 17 via a hydraulic fluid line. In this embodiment, the main pump 14 is a swashplate type variable displacement hydraulic pump.

[0067] The regulator 13 is configured to control the discharge rate of the main pump 14. In this embodiment, the regulator 13 controls the discharge rate of the main pump 14 by adjusting the swash plate tilt angle of the main pump 14 in response to a control command from the controller 30.

[0068] As described above, the pilot pump 15 is configured to supply hydraulic fluid to the hydraulic control equipment via the pilot line.

[0069] As described above, the control valve unit 17 includes control valves 171 to 176. Control valve 175 includes control valves 175L and 175R, and control valve 176 includes control valves 176L and 176R. As described above, the control valve unit 17 is configured to selectively supply the hydraulic fluid discharged by the main pump 14 to one or more hydraulic actuators through control valves 171 to 176. As described above, control valves 171 to 176 control the flow rate of hydraulic fluid flowing from the main pump 14 to the hydraulic actuators, and the flow rate of hydraulic fluid flowing from the hydraulic actuators to the hydraulic fluid tank. As described above, the hydraulic actuators include a boom cylinder 7, an arm cylinder 8, a bucket cylinder 9, a left travel hydraulic motor 2ML, a right travel hydraulic motor 2MR, and a slewing hydraulic motor 2A.

[0070] The operating device 26 is configured to allow an operator to operate the actuator. In this embodiment, the operating device 26 includes a hydraulic actuator operating device configured to allow an operator to operate a hydraulic actuator. Specifically, the hydraulic actuator operating device is configured to supply hydraulic fluid discharged by the pilot pump 15 to the pilot port of the corresponding control valve in the control valve unit 17 via a pilot line. The pressure of the hydraulic fluid supplied to each pilot port (pilot pressure) is a pressure corresponding to the operating direction and amount of the operating device 26 corresponding to each hydraulic actuator.

[0071] As described above, the discharge pressure sensor 28 detects the discharge pressure of the main pump 14 and outputs the detected value to the controller 30. As described above, the operation sensor 29 detects the operation of the operation device 26 by the operator, detects the operating direction and amount of the operation device 26 corresponding to each actuator, and outputs the detected value to the controller 30.

[0072] The main pump 14 includes a left main pump 14L and a right main pump 14R. The left main pump 14L circulates the hydraulic fluid to the hydraulic fluid tank via the left center bypass pipeline 40L or the left parallel pipeline 42L, while the right main pump 14R circulates the hydraulic fluid to the hydraulic fluid tank via the right center bypass pipeline 40R or the right parallel pipeline 42R.

[0073] The left center bypass pipeline 40L is a hydraulic fluid line that passes through control valves 171, 173, 175L, and 176L located within the control valve unit 17. The right center bypass pipeline 40R is a hydraulic fluid line that passes through control valves 172, 174, 175R, and 176R located within the control valve unit 17.

[0074] The control valve 171 is a spool valve that supplies the hydraulic fluid discharged by the left main pump 14L to the left travel hydraulic motor 2ML, and switches the flow of hydraulic fluid to discharge the hydraulic fluid discharged by the left travel hydraulic motor 2ML to the hydraulic fluid tank.

[0075] The control valve 172 is a spool valve that supplies the hydraulic fluid discharged by the right main pump 14R to the right travel hydraulic motor 2MR, and switches the flow of hydraulic fluid to discharge the hydraulic fluid discharged by the right travel hydraulic motor 2MR to the hydraulic fluid tank.

[0076] The control valve 173 is a spool valve that supplies the hydraulic fluid discharged by the left main pump 14L to the swivel hydraulic motor 2A, and switches the flow of hydraulic fluid to discharge the hydraulic fluid discharged by the swivel hydraulic motor 2A to the hydraulic fluid tank.

[0077] The control valve 174 is a spool valve that supplies the hydraulic fluid discharged by the right main pump 14R to the bucket cylinder 9 and switches the flow of the hydraulic fluid in order to discharge the hydraulic fluid in the bucket cylinder 9 to the hydraulic fluid tank.

[0078] Control valve 175L is a spool valve that switches the flow of hydraulic fluid to supply the hydraulic fluid discharged by the left main pump 14L to the boom cylinder 7. Control valve 175R is a spool valve that supplies the hydraulic fluid discharged by the right main pump 14R to the boom cylinder 7 and also switches the flow of hydraulic fluid to discharge the hydraulic fluid inside the boom cylinder 7 to the hydraulic fluid tank.

[0079] Control valve 176L is a spool valve that supplies the hydraulic fluid discharged by the left main pump 14L to the arm cylinder 8 and switches the flow of hydraulic fluid to discharge the hydraulic fluid in the arm cylinder 8 to the hydraulic fluid tank. Control valve 176R is a spool valve that supplies the hydraulic fluid discharged by the right main pump 14R to the arm cylinder 8 and switches the flow of hydraulic fluid to discharge the hydraulic fluid in the arm cylinder 8 to the hydraulic fluid tank.

[0080] The left parallel pipeline 42L is a hydraulic fluid line running parallel to the left center bypass pipeline 40L. The left parallel pipeline 42L can supply hydraulic fluid to a control valve further downstream if the flow of hydraulic fluid through the left center bypass pipeline 40L is restricted or blocked by any of the control valves 171, 173, and 175L. The right parallel pipeline 42R is a hydraulic fluid line running parallel to the right center bypass pipeline 40R. The right parallel pipeline 42R can supply hydraulic fluid to a control valve further downstream if the flow of hydraulic fluid through the right center bypass pipeline 40R is restricted or blocked by any of the control valves 172, 174, and 175R.

[0081] The regulator 13 includes a left regulator 13L and a right regulator 13R. The left regulator 13L controls the discharge volume of the left main pump 14L by adjusting the swash plate tilt angle of the left main pump 14L in accordance with the discharge pressure of the left main pump 14L. Specifically, the left regulator 13L reduces the discharge volume by adjusting the swash plate tilt angle of the left main pump 14L in accordance with an increase in the discharge pressure of the left main pump 14L. The same applies to the right regulator 13R. This is to ensure that the absorption power (absorption horsepower) of the main pump 14, which is expressed as the product of the discharge pressure and the discharge volume, does not exceed the output power (output horsepower) of the engine 11.

[0082] The operating device 26 includes a left operating lever 26L, a right operating lever 26R, and a travel lever 26D. The travel lever 26D includes a left travel lever 26DL and a right travel lever 26DR.

[0083] The left operating lever 26L is used for slewing and operating the arm 5. When the left operating lever 26L is operated in the forward / backward direction, it uses the hydraulic fluid discharged by the pilot pump 15 to introduce a control pressure corresponding to the lever operation amount into the pilot port of the control valve 176. When it is operated in the left / right direction, it uses the hydraulic fluid discharged by the pilot pump 15 to introduce a control pressure corresponding to the lever operation amount into the pilot port of the control valve 173.

[0084] Specifically, when the left operating lever 26L is operated in the arm closing direction, it introduces hydraulic fluid into the right pilot port of control valve 176L and into the left pilot port of control valve 176R. When the left operating lever 26L is operated in the arm opening direction, it introduces hydraulic fluid into the left pilot port of control valve 176L and into the right pilot port of control valve 176R. Furthermore, when the left operating lever 26L is operated in the left rotation direction, it introduces hydraulic fluid into the left pilot port of control valve 173, and when operated in the right rotation direction, it introduces hydraulic fluid into the right pilot port of control valve 173.

[0085] In the example shown in Figure 3, the left operating lever 26L functions as an arm operating lever when operated in the forward / backward direction and as a swivel operating lever when operated in the left / right direction. The left operating lever 26L is equipped with a switch NS (NSL). In this embodiment, switch NS is a push-button switch located at the tip of the left operating lever 26L. The operator can operate the left operating lever 26L while pressing switch NS.

[0086] The right operating lever 26R is used to operate the boom 4 and the bucket 6. When the right operating lever 26R is operated in the forward / backward direction, it uses the hydraulic fluid discharged by the pilot pump 15 to introduce a control pressure corresponding to the lever operation amount into the pilot port of the control valve 175. When it is operated in the left / right direction, it uses the hydraulic fluid discharged by the pilot pump 15 to introduce a control pressure corresponding to the lever operation amount into the pilot port of the control valve 174.

[0087] Specifically, when the right operating lever 26R is operated in the boom lowering direction, it introduces hydraulic fluid into the left pilot port of the control valve 175R. When the right operating lever 26R is operated in the boom raising direction, it introduces hydraulic fluid into the right pilot port of the control valve 175L and into the left pilot port of the control valve 175R. Furthermore, when the right operating lever 26R is operated in the bucket closing direction, it introduces hydraulic fluid into the right pilot port of the control valve 174, and when it is operated in the bucket opening direction, it introduces hydraulic fluid into the left pilot port of the control valve 174.

[0088] In the example shown in Figure 3, the right operating lever 26R functions as a boom operating lever when operated in the forward / backward direction and as a bucket operating lever when operated in the left / right direction. A switch NS (NSR) may also be provided on the right operating lever 26R, or the switch NS may be located at another position within the cabin 10.

[0089] The travel lever 26D is used to operate the crawler. Specifically, the left travel lever 26DL is used to operate the left crawler. The left travel lever 26DL may be configured to be linked with the left travel pedal. When the left travel lever 26DL is operated in the forward or backward direction, it uses the hydraulic fluid discharged by the pilot pump 15 to introduce a control pressure corresponding to the lever operation amount into the pilot port of the control valve 171. The right travel lever 26DR is used to operate the right crawler. The right travel lever 26DR may be configured to be linked with the right travel pedal. When the right travel lever 26DR is operated in the forward or backward direction, it uses the hydraulic fluid discharged by the pilot pump 15 to introduce a control pressure corresponding to the lever operation amount into the pilot port of the control valve 172.

[0090] The discharge pressure sensor 28 includes discharge pressure sensors 28L and 28R. Discharge pressure sensor 28L detects the discharge pressure of the left main pump 14L and outputs the detected value to the controller 30. The same applies to discharge pressure sensor 28R.

[0091] The operation sensor 29 includes operation sensors 29LA, 29LB, 29RA, 29RB, 29DL, and 29DR. Operation sensor 29LA detects the operator's forward and backward movement of the left operation lever 26L and outputs the detected value to the controller 30. The operation details include, for example, the direction of lever operation and the amount of lever operation (lever operation angle).

[0092] Similarly, the operation sensor 29LB detects the operator's left-right operation of the left operation lever 26L and outputs the detected value to the controller 30. The operation sensor 29RA detects the operator's forward-backward operation of the right operation lever 26R and outputs the detected value to the controller 30. The operation sensor 29RB detects the operator's left-right operation of the right operation lever 26R and outputs the detected value to the controller 30. The operation sensor 29DL detects the operator's forward-backward operation of the left travel lever 26DL and outputs the detected value to the controller 30. The operation sensor 29DR detects the operator's forward-backward operation of the right travel lever 26DR and outputs the detected value to the controller 30.

[0093] In this embodiment, the description of the operating device 26 is based on a hydraulic operating lever equipped with a hydraulic pilot circuit. However, an electric operating lever equipped with an electric pilot circuit may be used instead of a hydraulic operating lever. In this case, the amount of lever operation of the electric operating lever is input to the controller 30 as an electrical signal. A solenoid valve is also placed between the pilot pump 15 and the pilot port of each control valve. The solenoid valve is configured to operate in response to an electrical signal from the controller 30. With this configuration, when manual operation is performed using the electric operating lever, the controller 30 can move each control valve by controlling the solenoid valve with an electrical signal corresponding to the amount of lever operation to increase or decrease the pilot pressure. Note that each control valve may be composed of an electromagnetic spool valve. In this case, the electromagnetic spool valve operates in response to an electrical signal from the controller 30 corresponding to the amount of lever operation of the electric operating lever.

[0094] The controller 30 receives the output of the operation sensor 29 and, if necessary, outputs a control command to the regulator 13 to change the discharge amount of the main pump 14. The controller 30 also receives the output of the control pressure sensor 19 located upstream of the throttle 18 and, if necessary, outputs a control command to the regulator 13 to change the discharge amount of the main pump 14. The throttle 18 includes a left throttle 18L and a right throttle 18R, and the control pressure sensor 19 includes a left control pressure sensor 19L and a right control pressure sensor 19R.

[0095] In the left center bypass pipeline 40L, a left throttle 18L is located between the control valve 176L, the downstreammost control valve, and the hydraulic fluid tank. Therefore, the flow of hydraulic fluid discharged by the left main pump 14L is restricted by the left throttle 18L. The left throttle 18L then generates a control pressure to control the left regulator 13L. The left control pressure sensor 19L is a sensor for detecting this control pressure and outputs the detected value to the controller 30. The controller 30 controls the discharge amount of the left main pump 14L by adjusting the swash plate tilt angle of the left main pump 14L in accordance with this control pressure. The controller 30 decreases the discharge amount of the left main pump 14L as the control pressure increases, and increases the discharge amount of the left main pump 14L as the control pressure decreases. The discharge amount of the right main pump 14R is controlled in the same way.

[0096] Specifically, as shown in Figure 3, when the hydraulic actuators in the shovel 100 are in a standby state and not being operated, the hydraulic fluid discharged from the left main pump 14L passes through the left center bypass pipe 40L to the left constriction 18L. The flow of hydraulic fluid discharged from the left main pump 14L increases the control pressure generated upstream of the left constriction 18L. As a result, the controller 30 reduces the discharge volume of the left main pump 14L to the minimum allowable discharge volume, suppressing the pressure loss (pumping loss) as the discharged hydraulic fluid passes through the left center bypass pipe 40L. On the other hand, when any of the hydraulic actuators are operated, the hydraulic fluid discharged from the left main pump 14L flows into the operated hydraulic actuator via the control valve corresponding to the operated hydraulic actuator. The flow of hydraulic fluid discharged from the left main pump 14L reduces or eliminates the amount reaching the left constriction 18L, lowering the control pressure generated upstream of the left constriction 18L. As a result, the controller 30 increases the discharge volume of the left main pump 14L, ensuring sufficient hydraulic fluid circulation to the hydraulic actuator being operated and guaranteeing reliable operation of the hydraulic actuator. The controller 30 also controls the discharge volume of the right main pump 14R in the same manner.

[0097] With the configuration described above, the hydraulic system in Figure 3 can suppress unnecessary energy consumption in the main pump 14 when in standby mode. Unnecessary energy consumption includes pumping losses caused by the hydraulic fluid discharged by the main pump 14 in the center bypass pipeline 40. Furthermore, when operating a hydraulic actuator, the hydraulic system in Figure 3 can reliably supply the necessary and sufficient hydraulic fluid from the main pump 14 to the hydraulic actuator being operated.

[0098] Furthermore, boom cylinder 7 is equipped with boom rod pressure sensor S7R and boom bottom pressure sensor S7B. Arm cylinder 8 is equipped with arm rod pressure sensor S8R and arm bottom pressure sensor S8B. Bucket cylinder 9 is equipped with bucket rod pressure sensor S9R and bucket bottom pressure sensor S9B. The boom rod pressure sensor S7R, boom bottom pressure sensor S7B, arm rod pressure sensor S8R, arm bottom pressure sensor S8B, bucket rod pressure sensor S9R, and bucket bottom pressure sensor S9B are collectively referred to as "cylinder pressure sensors". In addition, the swing hydraulic motor 2A is equipped with left swing pressure sensor S10L and right swing pressure sensor S10R.

[0099] The boom rod pressure sensor S7R detects the pressure in the rod-side oil chamber of the boom cylinder 7 (hereinafter referred to as "boom rod pressure"), and the boom bottom pressure sensor S7B detects the pressure in the bottom-side oil chamber of the boom cylinder 7 (hereinafter referred to as "boom bottom pressure"). The arm rod pressure sensor S8R detects the pressure in the rod-side oil chamber of the arm cylinder 8 (hereinafter referred to as "arm rod pressure"), and the arm bottom pressure sensor S8B detects the pressure in the bottom-side oil chamber of the arm cylinder 8 (hereinafter referred to as "arm bottom pressure"). The bucket rod pressure sensor S9R detects the pressure in the rod-side oil chamber of the bucket cylinder 9 (hereinafter referred to as "bucket rod pressure"), and the bucket bottom pressure sensor S9B detects the pressure in the bottom-side oil chamber of the bucket cylinder 9 (hereinafter referred to as "bucket bottom pressure"). The left slewing pressure sensor S10L detects the hydraulic fluid pressure at the left port of the slewing hydraulic motor 2A. The right slewing pressure sensor S10R detects the hydraulic fluid pressure at the right port of the slewing hydraulic motor 2A. The values ​​detected by each sensor are transmitted to the controller 30.

[0100] Next, with reference to Figures 4 and 5, the controller 30, which acts as a control device for controlling the operation of the attachment AT, will be described. Figure 4 is a flowchart illustrating the processing flow of the controller 30 that controls the operation of the attachment AT. Figure 5 is a process diagram showing an example of the excavation work of the shovel 100 under the control of the controller 30.

[0101] The controller 30 includes, for example, an excavation motion generation unit 301, a stop state detection unit 302, and an excavation completion determination unit 303, as shown in Figure 2. The controller 30 automatically assists the excavation work of the shovel 100 shown in Figure 5 by controlling the operation of the attachment AT according to, for example, the processing flow shown in Figure 4.

[0102] When the operator of the shovel 100 selects to start automatic excavation work by operating the input device D2 or switch NS, the controller 30 starts the processing flow shown in Figure 4 and executes process P1 to generate the excavation motion. In this process P1, the excavation motion generation unit 301 controls the actuator of the shovel 100 by its automatic operation function to cause the attachment AT to perform the excavation work. The automatic operation function of the excavation motion generation unit 301 may be a fully automatic operation function that does not require operation of the operating device 26 by the operator, or it may be a semi-automatic operation function that automatically operates at least one of the boom 4, arm 5, or bucket 6 in response to operation of the operating device 26 by the operator.

[0103] Specifically, in this process P1, the drilling motion generation unit 301 acquires the current shape and target shape of the drilling target EO based on, for example, the recognition results of the external environment recognition device 70 such as the imaging device S6 or LiDAR, or data input by the operator via the input device D2. Here, the drilling target EO is, for example, the soil on the ground surface of the work site. The current shape of the drilling target EO is the current surface shape of the drilling target EO, and the target shape of the drilling target EO is the surface shape of the drilling target EO when the drilling work is completed.

[0104] Furthermore, in this process P1, the excavation motion generation unit 301 sets, for example, the target path TR of the bucket 6's claws necessary to change the current shape of the excavation target EO to the target shape. Also in this process P1, the excavation motion generation unit 301 calculates, for example, the target posture of the attachment AT necessary to move the bucket 6's claws along the target path TR.

[0105] Furthermore, in this process P1, the excavation motion generation unit 301 acquires the current posture of the attachment AT based on the detection results of the boom angle sensor S1, arm angle sensor S2, bucket angle sensor S3, machine body tilt sensor S4, and slewing angle sensor S5, etc. Then, the excavation motion generation unit 301 drives the boom cylinder 7, arm cylinder 8, bucket cylinder 9, etc. via the proportional valve 31 and control valve unit 17 so that the current posture of the attachment AT becomes the target posture.

[0106] As a result, for example, as shown in the upper diagram of Figure 5, the attachment AT performs the closing operation of the arm 5 and the lowering operation of the boom 4 while maintaining the bucket angle, causing the tip of the bucket 6 to move along the target path TR. This enables the attachment AT to perform the excavation operation of the target EO.

[0107] Next, as shown in Figure 4, the controller 30 executes a process P2 to determine whether or not the attachment AT is in a drilling stop state. In this process P2, the stop state detection unit 302 determines whether or not the drilling operation of the attachment AT has stopped due to receiving a drilling reaction force from the drilling target EO.

[0108] Specifically, the stop state detection unit 302 determines, for example, based on the detection results of sensors, whether the attachment AT is in a stopped state, having stopped due to receiving an excavation reaction force from the excavation target EO. ​​This stop state detection device, such as a sensor, for detecting the stop state of the attachment AT includes, for example, one or more cylinder pressure sensors. The cylinder pressure sensors include, as described above, a boom rod pressure sensor S7R, a boom bottom pressure sensor S7B, an arm rod pressure sensor S8R, an arm bottom pressure sensor S8B, a bucket rod pressure sensor S9R, and a bucket bottom pressure sensor S9B.

[0109] Furthermore, the stop state detection device for detecting the stopped state of the attachment AT may include an attitude sensor for detecting the attitude of the attachment AT. The attitude sensor includes, as described above, a boom angle sensor S1, an arm angle sensor S2, and a bucket angle sensor S3. The attitude sensor is, as described above, an acceleration sensor, a potentiometer, a stroke sensor for detecting the stroke amount of the corresponding hydraulic cylinder, or a rotary encoder for detecting the rotation angle around the connecting pin.

[0110] Furthermore, the stop state detection device for detecting the stopped state of the attachment AT may include, for example, an external environment recognition device 70 such as an imaging device S6, or a force sensor for detecting the force acting on the claws of the bucket 6. The stop state detection device may also include, for example, a spool displacement sensor for detecting the displacement of the spools constituting each of the control valves 174 to 176 corresponding to the bucket cylinder 9, boom cylinder 7, and arm cylinder 8.

[0111] In process P2, the stop state detection unit 302 determines, for example, that the digging operation of the attachment AT is in a stopped state (YES) due to receiving a digging reaction force from the digging target EO, if the detection result of one or more cylinder pressure sensors exceeds a predetermined threshold. In this case, the threshold for the detection result of the cylinder pressure sensor can be set, for example, to the relief pressure of each cylinder.

[0112] Furthermore, in this process P2, the stop state detection unit 302 determines that the attachment AT is in a stopped state (YES) if, for example, the rate of change of the boom angle, arm angle, or bucket angle detected by the attitude sensor is below a predetermined threshold. Also in this process P2, the stop state detection unit 302 determines that the attachment AT is in a stopped state (YES) if, for example, the operation of the attachment AT recognized by the external recognition device 70 such as the imaging device S6 or LiDAR has stopped. Also in this process P2, the stop state detection unit 302 determines that the attachment AT is in a stopped state (YES) if, for example, the force acting on the claws of the bucket 6 detected by the force sensor exceeds a predetermined threshold.

[0113] Furthermore, in this process P2, the stop state detection unit 302 may, for example, calculate the flow rate of hydraulic fluid that has passed through each of the control valves 174 to 176 based on the displacement of the spools constituting each of the control valves 174 to 176 detected by the spool displacement sensor. In this case, the stop state detection unit 302 calculates the stroke of the bucket cylinder 9, boom cylinder 7, and arm cylinder 8 by calculating the integral value of the flow rate of hydraulic fluid that has passed through each of the control valves 174 to 176. The stop state detection unit 302 determines that the attachment AT is in a stopped state (YES) if, for example, the rate of change of the stroke of the bucket cylinder 9, boom cylinder 7, or arm cylinder 8 is below a predetermined threshold.

[0114] In this process P2, if the excavation reaction force acting on the attachment AT is small and the stop state detection unit 302 determines that the attachment AT is not in a stopped state (NO), the controller 30 executes process P4 to determine whether or not the excavation work has been completed. In this process P4, the excavation completion determination unit 303 acquires the current shape of the excavation target EO based on the recognition results of the external environment recognition device 70, such as the imaging device S6 or LiDAR, and compares it with the target shape set in the above-mentioned process P1.

[0115] If the difference between the current shape of the target EO and the target shape is within a predetermined error range, the drilling completion determination unit 303 determines that the drilling work is complete (YES), and the controller 30 terminates the processing flow shown in Figure 4. On the other hand, if the difference between the current shape of the target EO and the target shape exceeds a predetermined error range, the drilling completion determination unit 303 determines that the drilling work is not complete (NO), and the controller 30 repeats each of the processes from process P1 onwards described above.

[0116] Furthermore, for example, as shown in the upper part of Figure 5, suppose that the soil on the ground surface of the work site, which is the target of excavation EO, has a hard ground SG in the middle of the excavation path of the bucket 6 moving along the target path TR. In this case, the attachment AT may receive a large excavation reaction force from the hard ground SG of the target of excavation EO, causing the excavation operation of the attachment AT to stop. Then, in the aforementioned process P2, the stop state detection unit 302 detects and determines that the excavation operation of the attachment AT has stopped due to the excavation reaction force from the target of excavation EO (YES).

[0117] In this case, the controller 30 executes a process P3 that causes the bucket 6 to close, as shown in Figure 4. In this process P3, the excavation motion generation unit 301 causes the bucket 6 of the stopped attachment AT to close, for example, as shown in the middle of Figure 5. More specifically, in the excavation motion of the process P1 described above, the attachment AT performs a closing operation of the arm 5 and a lowering operation of the boom 4 while maintaining the bucket angle, or performs a closing operation of the arm 5 while maintaining the bucket angle and boom angle, for example, as shown in the upper of Figure 5. Then, the tip of the bucket 6 moves along the target path TR.

[0118] In contrast, in the bucket 6 closing operation of process P3, when the attachment AT is detected to be stopped in process P2, the tip of the bucket 6 is allowed to deviate from the target path TR, as shown in the middle of Figure 5. In this bucket 6 closing operation, the bucket 6 is closed more forcefully at a larger bucket angle than in the excavation operation of the attachment AT in process P1. This allows the hard ground SG to be excavated with a stronger excavation force from the bucket 6, thereby resolving the stopped state of the attachment AT.

[0119] In other words, by additionally closing the bucket 6 while the attachment AT is stopped, a greater digging force can be applied to the hard ground SG compared to digging operations where the bucket angle is maintained or the bucket 6 is closed at a smaller bucket angle. This is because the distance from the bucket pin that rotatably supports the bucket 6 to the tip of the bucket 6 that applies digging force to the hard ground SG is shorter than the distance from the boom top pin that rotatably supports the arm 5 to the tip of the bucket 6.

[0120] In other words, because the distance from the pivot axis of the bucket 6 to the tip of the bucket 6 is shorter than the distance from the pivot axis of the arm 5 to the tip of the bucket 6, the digging reaction force acting on the bucket cylinder 9 is smaller than the digging reaction force acting on the arm cylinder 8. Therefore, even if the digging reaction force acting on the arm cylinder 8 exceeds the maximum thrust of the arm cylinder 8 and the attachment AT comes to a stop, the bucket cylinder 9 can output a thrust exceeding the digging reaction force, causing the bucket 6 to close, thereby enabling excavation of the hard ground SG.

[0121] Furthermore, the controller 30 may notify the operator of the shovel 100 regarding the closing operation of the bucket 6 via the display device D1 or the audio output device before the attachment AT stops and the bucket 6 is closed. In this case, the controller 30 may close the bucket 6 when the operator inputs permission to close the bucket 6 via the input device D2.

[0122] Furthermore, in the example shown in the middle of Figure 5, the excavation motion generation unit 301 maintains the posture of the boom 4 and arm 5 during the closing operation of the bucket 6 when the stop state detection unit 302 detects that the attachment AT is stopped. In addition, the excavation motion generation unit 301 causes the bucket 6 to open when the closing operation of the bucket 6 is completed, returning the posture of the attachment AT to the posture it was in when the stop state detection unit 302 detected that it was stopped.

[0123] In this case, the controller 30 may, at the end of the closing operation of the bucket 6, confirm with the operator of the shovel 100 via the display device D1 or the audio output device whether or not to open the bucket 6. Alternatively, the controller 30 may cause the bucket 6 to open if the operator selects to open the bucket 6 via the input device D2.

[0124] Subsequently, in process P4, the excavation completion determination unit 303 determines that the excavation work is not yet complete (NO), and the excavation operation that was interrupted in process P1 is resumed by the excavation operation generation unit 301. As a result, as shown in the lower part of Figure 5, the excavation target EO, from which the hard ground SG has been removed, can be excavated by the excavation operation of the attachment AT, and the claws of the bucket 6 can be moved along the target path TR.

[0125] Therefore, the attachment AT does not enter a stopped state during the excavation operation, and in process P2, the stop state detection unit 302 determines that the attachment AT is not in a stopped state (NO). Subsequently, in process P4, when the excavation completion determination unit 303 determines that the excavation work has been completed (YES), the controller 30 terminates the processing flow shown in Figure 4.

[0126] The operation of the excavator 100 of this embodiment will be explained below in comparison with the conventional hydraulic excavator described in the aforementioned Patent Document 1.

[0127] The conventional hydraulic excavator described in Patent Document 1 has a control device that changes the boom angle to deflect the bucket's direction of travel upward when the excavation reaction force received by the bucket from the ground is large. Therefore, when the excavation reaction force received by the bucket from the ground is large, the amount of soil and other materials scooped up by the bucket decreases, which may reduce work efficiency.

[0128] On the other hand, the excavator 100 of this embodiment comprises a lower traveling body 1, an upper rotating body 3 rotatably mounted on the lower traveling body 1, an attachment AT attached to the upper rotating body 3, and a controller 30 as a control device for controlling the operation of the attachment AT. The attachment AT includes a boom 4 rotatably supported on the upper rotating body 3, an arm 5 rotatably supported on the boom 4, and a bucket 6 rotatably supported on the arm 5. When the controller 30 detects that the excavation operation of the attachment AT has stopped due to an excavation reaction force from the excavation target EO, it causes the bucket 6 to close.

[0129] With this configuration, even if the attachment AT of the excavator 100 stops due to the excavation reaction force from the excavation target EO during excavation, the bucket 6 can close to excavate the excavation target EO, thereby resolving the stop state of the attachment AT and continuing the excavation operation. As a result, even when the excavation reaction force is large, compared to conventional hydraulic excavators where the boom angle is changed to deflect the direction of travel of the bucket upward, the reduction in the amount of excavated excavation target EO scooped up by the bucket 6 can be suppressed, thereby suppressing a decrease in work efficiency.

[0130] Furthermore, in the excavator 100 of this embodiment, the controller 30, acting as a control device, maintains the posture of the boom 4 and arm 5 while the bucket 6 is closing, as shown in the middle section of Figure 5. Also, as shown in the middle section of Figure 5, the controller 30 causes the bucket 6 to open when the closing operation of the bucket 6 is completed, returning the posture of the attachment AT to the posture it was in when the stop state was detected.

[0131] With this configuration, the shovel 100 can excavate the target EO by closing the bucket 6 while the attachment AT is stopped, and then move the tip of the bucket 6 along the target path TR. This more effectively suppresses the reduction in the amount of excavated target EO scooped up by the bucket 6, and allows the target EO to be excavated along the target path TR, thereby more effectively suppressing the decrease in work efficiency.

[0132] Furthermore, the controller 30 in this embodiment is a control device that controls the operation of the attachment AT of the shovel 100. As described above, the shovel 100 comprises a lower traveling body 1, an upper rotating body 3 that is rotatably mounted on the lower traveling body 1, and the attachment AT. The attachment AT includes a boom 4 that is rotatably supported on the upper rotating body 3, an arm 5 that is rotatably supported on the boom 4, and a bucket 6 that is rotatably supported on the arm 5. The controller 30 closes the bucket 6 when it detects that the digging operation of the attachment AT has stopped due to the digging reaction force from the digging target EO.

[0133] With this configuration, even if the attachment AT stops due to the excavation reaction force from the excavation target EO during excavation, the controller 30 can close the bucket 6 to excavate the excavation target EO, thereby resolving the stopped state of the attachment AT and continuing the excavation operation. As a result, even when the excavation reaction force is large, compared to conventional hydraulic excavators where the boom angle is changed to deflect the direction of travel of the bucket upward, the reduction in the amount of excavated excavation target EO scooped up by the bucket 6 can be suppressed, thereby suppressing a decrease in work efficiency.

[0134] As described above, this embodiment provides a shovel 100 and a controller 30 as its control device that can suppress a decrease in work efficiency even when the excavation reaction force is large. It should be noted that the shovel and control device according to this disclosure are not limited to the configuration of the embodiments described above.

[0135] For example, the controller 30 does not need to perform an opening operation on the bucket 6 after performing a closing operation on the bucket 6 while the attachment AT is stopped. Specifically, in the excavator 100 of this embodiment, the controller 30, as a control device, may maintain the posture of the boom 4 and arm 5 while the bucket 6 is closing, as shown in the middle of Figure 5, and raise the boom 4 when the bucket 6 is finished closing.

[0136] With this configuration, the hard ground SG of the target EO that caused the attachment AT to stop can be scooped up by the closing motion of the bucket 6, and then lifted by the raising motion of the boom 4 and moved to another location. In this case, the tip of the bucket 6 deviates from the target path TR, but the attachment AT can continue excavating the target EO, from which the hard ground SG has been removed, without stopping during the next excavation operation.

[0137] Furthermore, in the excavator 100 of this embodiment, the controller 30, as a control device, may maintain the posture of the boom 4 and continue the closing operation of the arm 5 while the bucket 6 is being closed when the attachment AT is detected to be stopped.

[0138] With this configuration, the hard ground SG of the excavation target EO that caused the attachment AT to stop can be scooped up by the closing action of the bucket 6, thereby resolving the stoppage, while the closing action of the arm 5 allows for the scooping up of more of the excavation target EO. ​​Specifically, compared to the example shown in the middle of Figure 5, more of the excavation target EO on the front side of the bucket 6 can be scooped up by the bucket 6.

[0139] Next, referring to Figures 6 and 7, we will explain how the controller 30 controls the attachment AT when the stopped state is detected and the stopped state is not resolved by the closing operation of the bucket 6. Figure 6 is a flowchart illustrating the processing flow of the controller 30 that controls the operation of the attachment AT. Figure 7 is a process diagram showing an example of the excavation work of the shovel 100 under the control of the controller 30.

[0140] In the example shown in Figure 6, the controller 30 determines in process P2 that the attachment AT is in a stopped state (YES), and when the bucket 6 is being closed in process P2, it executes the stop state determination process P5. Specifically, in this process P5, similar to the process P2 described above, the stop state detection unit 302 determines whether the attachment AT is in a stopped state, having stopped its excavation operation due to receiving an excavation reaction force from the excavation target EO.

[0141] In this process P5, if hard ground SG is excavated by the closing operation of bucket 6, the stop state detection unit 302 determines that the attachment AT is not in a stopped state (NO). In this case, the controller 30 executes process P4 to determine whether or not the excavation work has been completed, similar to the process flow shown in Figure 4.

[0142] On the other hand, in process P5, as shown in the middle of Figure 7, if the hard ground SG cannot be excavated even by the closing operation of the bucket 6 and the stopped state continues, the stopped state detection unit 302 determines that the attachment AT is in a stopped state (YES). In this case, the controller 30 executes process P6, which causes the boom 4 to perform a lifting operation, as shown in Figure 6. As a result, as shown in the lower part of Figure 7, the bucket 6 moves above the hard ground SG, and the stopped state of the attachment AT can be resolved.

[0143] As described above, in the excavator 100 of this embodiment, the controller 30, which acts as a control device, may raise the boom 4 if it detects that the attachment AT is stopped again while the bucket 6 is being closed. With this configuration, if the stopped state of the attachment AT cannot be resolved by closing the bucket 6 when the stopped state of the attachment AT is detected, the stopped state of the attachment AT can be resolved by raising the boom 4.

[0144] Furthermore, as shown in the middle section of Figure 7, if the controller 30 detects that the attachment AT is stopped again while the bucket 6 is closing, it may perform an opening operation on the bucket 6 to return the tip of the bucket 6 to the target path TR. This separates the tip of the bucket 6 from the hard ground SG, making it easier to raise the boom 4.

[0145] Furthermore, the controller 30 may simultaneously perform the raising of the boom 4 of the processing P6 and the closing of the arm 5 and / or the closing of the bucket 6. This makes it possible to excavate more of the target area EO by at least one of the closing of the arm 5 and the closing of the bucket 6 when the tip of the bucket 6 moves above the hard ground SG due to the raising of the boom 4.

[0146] Next, an embodiment of the control device according to the present disclosure will be described with reference to Figure 8. Figure 8 is a block diagram showing an embodiment of the control device according to the present disclosure. The remote controller 30E, which serves as the control device in this embodiment, constitutes part of the operating system SYS of the shovel 100.

[0147] The excavator operating system SYS of this embodiment includes, for example, the excavator 100 and the remote control room RC. Note that the detailed configuration of the excavator 100 is omitted from Figure 8 because the excavator 100 shown in Figure 8 has the same configuration as the excavator 100 shown in Figure 1.

[0148] The shovel 100 and the remote control room RC are connected to each other so that data can be sent and received via the remote communication device 60E and the communication line NW. Alternatively, the shovel 100 and the remote control room RC may be connected to each other so that data can be sent and received directly without using the communication line NW. In the illustrated example, the shovel 100 transmits information about the work site and the detection results of each sensor to the remote control room RC. This allows the remote operator RO in the remote control room RC to understand the situation at the work site and the status of the shovel 100 based on the information from the shovel 100.

[0149] The shovel 100 is equipped with sensors capable of recognizing the position and shape of objects present at the work site in three dimensions. For example, the shovel 100 is equipped with an external environment recognition device 70. Therefore, the shovel 100 can transmit the results of three-dimensional measurements of the work site to the remote control room RC.

[0150] The external environment recognition device 70 is a device for recognizing the space surrounding the shovel 100. In the illustrated example, the spatial recognition device is a LiDAR. The LiDAR measures, for example, the distance between the LiDAR and each of more than one million points within the monitoring range. The external environment recognition device 70 can be any device capable of measuring the distance to an object. For example, the external environment recognition device 70 may be a stereo camera, or a combination of an imaging device S6 and a ranging device such as a millimeter-wave radar.

[0151] The operating system SYS may include one or more excavators 100. If it includes multiple excavators 100, the remote operator RO operating a specific excavator 100 can obtain information about the work sites obtained by that specific excavator 100, as well as information about the work sites obtained by one or more other excavators 100.

[0152] The remote control room RC is equipped with a remote communication device 60E, a remote controller 30E, a remote control device 26E, an operation sensor 29E, and a remote output device 50E including a display device. The remote control room RC also has an operator's seat DS where the remote operator RO sits to remotely control the shovel 100.

[0153] The remote communication device 60E is configured to communicate with the communication device T1 attached to the shovel 100.

[0154] The remote controller 30E is a computing device that performs various calculations. In this embodiment, the remote controller 30E is composed of a microcomputer including a CPU and memory. The various functions of the remote controller 30E are realized by the CPU executing a program stored in memory.

[0155] The remote controller 30E, like the controller 30 mounted on the excavator 100, also functions as a control device for controlling the operation of the attachment AT of the excavator 100. That is, similar to the controller 30 mounted on the excavator 100, the remote controller 30E can close the bucket 6 when it detects that the excavation operation of the attachment AT has stopped due to the excavation reaction force from the excavation target EO.

[0156] The display device included in the remote output device 50E is a device capable of displaying various types of information. The display device displays images based on information transmitted from the shovel 100 so that the remote operator RO in the remote control room RC can visually inspect the area around the shovel 100. In the illustrated example, the display device is a liquid crystal display that displays images captured by the imaging device S6 mounted on the shovel 100. The display device may also be a display or projector that enables naked-eye stereoscopic viewing, or it may be a VR goggle or the like.

[0157] The remote control device 26E is equipped with an operation sensor 29E for detecting the operation of the remote control device 26E. The operation sensor 29E is, for example, a tilt sensor that detects the tilt angle of the operating lever, or an angle sensor that detects the oscillation angle of the operating lever around its pivot axis. The operation sensor 29E may also consist of other sensors such as a pressure sensor, a current sensor, a voltage sensor, or a distance sensor. The operation sensor 29E outputs information regarding the operation of the remote control device 26E that it has detected to the remote controller 30E. The remote controller 30E generates an operation signal based on the received information and transmits the generated operation signal to the shovel 100. The operation sensor 29E may be configured to generate the operation signal. In this case, the operation sensor 29E may output the operation signal to the remote communication device T1E without going through the remote controller 30E. With this configuration, the remote operator RO can remotely operate the shovel 100 from the remote control room RC.

[0158] As described above, the remote controller 30E of this embodiment is a control device that controls the operation of the attachment AT of the shovel 100. As previously mentioned, the shovel 100 comprises a lower traveling body 1, an upper rotating body 3 that is rotatably mounted on the lower traveling body 1, and the attachment AT. The attachment AT includes a boom 4 that is rotatably supported on the upper rotating body 3, an arm 5 that is rotatably supported on the boom 4, and a bucket 6 that is rotatably supported on the arm 5. The remote controller 30E closes the bucket 6 when it detects that the digging operation of the attachment AT has stopped due to the digging reaction force from the digging target EO.

[0159] With this configuration, even if the attachment AT stops due to the excavation reaction force from the excavation target EO during excavation, the remote controller 30E can close the bucket 6 to excavate the excavation target EO, thereby resolving the stopped state of the attachment AT and continuing the excavation operation. As a result, even when the excavation reaction force is large, compared to conventional hydraulic excavators where the boom angle is changed to deflect the direction of travel of the bucket upward, the reduction in the amount of excavated excavation target EO scooped up by the bucket 6 can be suppressed, thereby suppressing a decrease in work efficiency.

[0160] Preferred embodiments of the present disclosure have been described above. However, the inventions of the present disclosure are not limited to the embodiments described above. Various modifications, substitutions, etc., can be applied to the embodiments described above without departing from the scope of the inventions of the present disclosure. Furthermore, each of the features described with reference to the embodiments described above may be combined as appropriate, as long as they do not contradict each other technically.

[0161] For example, an excavator may have all or part of its driven parts, such as the lower traveling body, upper slewing body, boom, arm, and bucket, electrically driven. In other words, an excavator may be a hybrid excavator or electric excavator in which all or part of the driven parts are driven by electric actuators. Specifically, an excavator may be an electric excavator that drives all of its driven parts using only an electric motor as a power source. A hybrid excavator is typically an excavator that uses a combination of an internal combustion engine such as a diesel engine and an electric motor driven by a battery mounted on the upper slewing body as a power source, while an electric excavator is typically an excavator that uses only an electric motor driven by a battery mounted on the upper slewing body as a power source. However, an electric excavator may also be an excavator that uses only an electric motor connected to an external power source as a power source.

[0162] This disclosure can also be applied to other types of work machinery besides excavators, such as construction machinery, standard machines, applied machines, forestry machinery, or transport machinery based on hydraulic excavators. [Explanation of Symbols]

[0163] 1. Lower running body 3. Upper rotating body 4 Boom 5 Arms 6 buckets 30 Controller (control device) 30E Remote Controller (Control Device) 100 Shovel AT attachment

Claims

1. Lower running body and An upper rotating body is provided on the lower traveling body so as to be rotatable, An attachment comprising a boom rotatably supported on the upper rotating body, an arm rotatably supported on the boom, and a bucket rotatably supported on the arm, The system includes a control device for controlling the operation of the attachment, The control device, upon detecting a stopped state in which the excavation operation of the attachment has stopped due to an excavation reaction force from the excavation target, causes the bucket to close. Shovel.

2. The control device maintains the posture of the boom and the arm while the bucket is closing, and when the bucket is finished closing, it opens the bucket to return the posture of the attachment to the posture at the time the stopped state was detected. The shovel according to claim 1.

3. The control device maintains the posture of the boom and the arm while the bucket closing operation is being performed, and raises the boom when the bucket closing operation is completed. The shovel according to claim 1.

4. The control device maintains the posture of the boom and continues the closing operation of the arm while the closing operation of the bucket is being performed. The shovel according to claim 1.

5. The control device raises and operates the boom if the stopped state is detected again while the closing operation of the bucket is being performed. The shovel according to claim 1.

6. Lower running body and An upper rotating body is provided on the lower traveling body so as to be rotatable, An attachment comprising a boom rotatably supported on the upper rotating body, an arm rotatably supported on the boom, and a bucket rotatably supported on the arm, A control device for controlling the operation of the attachment of a shovel, comprising: When the excavation operation of the attachment is stopped due to an excavation reaction force from the object being excavated, the bucket is closed. Control device.

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