JP2024113561A - Shovel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shovel which can efficiently scoop sediment.

SOLUTION: A shovel includes an attachment including a boom, an arm and a bucket, and a control device for controlling excavation operation of the attachment, wherein the control device monitors the state of sediment on an opening side of the bucket during the excavation operation.

SELECTED DRAWING: Figure 6

COPYRIGHT: (C)2024,JPO&INPIT

Description

This disclosure relates to a shovel.

During excavation work with a shovel, the boom and arm are driven to move the bucket to the desired location, while the bucket is used to excavate soil and other materials. The soil scooped up by the bucket is then dumped at a designated location. Typically, the excavation operation involves inserting the bucket into the soil, and then closing the bucket while closing the arm (pulling it towards you).

When digging with a bucket, if the bucket is inserted too deeply into the soil, or if the soil being excavated is hard and heavy, the load on the bucket will be so great that it may become impossible to close the arm or the bucket.

Therefore, a conventional shovel is known that determines an overload during excavation operation by calculating an excavation reaction force from the position and posture of the working element, and controls the operation of the working element (see, for example, Patent Document 1).

JP 2011-252338 A

However, in the above-mentioned excavator, the excavation reaction force is calculated from the position and posture of the working elements to monitor overload during excavation operations, but the condition of the pile of soil is not taken into consideration. As a result, the amount of soil scooped up may be less than the bucket's volume.

Therefore, it is desirable to provide a shovel that can efficiently scoop up soil and sand.

The excavator according to an embodiment of the present invention includes an attachment including a boom, an arm, and a bucket, and a control device that controls the excavation operation of the attachment, and the control device monitors the condition of the soil on the opening side of the bucket during the excavation operation.

The above-mentioned means provide a shovel that can efficiently scoop up soil and sand.

FIG. 1 is a side view of a shovel according to an embodiment; FIG. 1 is a diagram showing an example of the configuration of a drive system of a shovel according to an embodiment; FIG. 1 is a diagram showing a configuration example of a hydraulic system of a shovel according to an embodiment; FIG. 1 is a diagram illustrating an example of components of an operation system in a hydraulic system of a shovel according to an embodiment. Diagram for explaining excavation and loading operations Flowchart showing an example of scooping processing FIG. 13 is a diagram showing parameters used for judgment in the scooping process.

Hereinafter, non-limiting exemplary embodiments of the present disclosure will be described with reference to the attached drawings. In all the attached drawings, the same or corresponding members or parts are denoted by the same or corresponding reference numerals, and duplicate descriptions will be omitted.

[Outline of the excavator]
First, an overview of a shovel 100 according to one embodiment will be described with reference to Fig. 1. Fig. 1 is a side view of the shovel 100 as an excavator according to one embodiment.

The excavator 100 comprises a lower carrier 1, an upper rotating body 3 mounted on the lower carrier 1 so as to be freely rotatable via a rotating mechanism 2, a boom 4, an arm 5, and a bucket 6 constituting an attachment (working machine), and a cabin 10.

The lower traveling body 1 allows the excavator 100 to travel by hydraulically driving a pair of left and right crawlers by traveling hydraulic motors 1L, 1R (see FIG. 2). In other words, the pair of traveling hydraulic motors 1L, 1R (an example of a traveling motor) drive the lower traveling body 1 (crawlers) as the driven part.

The upper rotating body 3 is driven by a hydraulic motor 2A (see FIG. 2) to rotate relative to the lower traveling body 1. In other words, the hydraulic motor 2A is a rotation drive unit that drives the upper rotating body 3 as a driven unit, and changes the orientation of the upper rotating body 3.

The upper rotating body 3 may be electrically driven by an electric motor (hereinafter referred to as the "swivel electric motor") instead of the swivel hydraulic motor 2A. In other words, the swivel electric motor, like the swivel hydraulic motor 2A, is a swivel drive unit that drives the upper rotating body 3 as a non-driven unit, and changes the orientation of the upper rotating body 3.

The boom 4 is attached to the center of the front of the upper rotating body 3 so that it can be raised and lowered. An arm 5 is attached to the tip of the boom 4 so that it can rotate up and down, and a bucket 6 is attached to the tip of the arm 5 so that it can rotate up and down as an end attachment. The boom 4, arm 5, and bucket 6 are hydraulically driven by a boom cylinder 7, arm cylinder 8, and bucket cylinder 9, which serve as hydraulic actuators, respectively.

The bucket 6 is an example of an end attachment, and instead of the bucket 6, a different end attachment, such as a slope bucket, a dredging bucket, or a breaker, may be attached to the tip of the arm 5 depending on the work content, etc.

The cabin 10 is the cab in which the operator sits and is mounted on the front left side of the upper rotating body 3.

[Excavator configuration]
Next, a specific configuration of the shovel 100 according to one embodiment will be described with reference to Fig. 2 in addition to Fig. 1. Fig. 2 is a diagram showing an example of the configuration of a drive system of the shovel 100 according to one embodiment. In Fig. 2, a mechanical power system, a hydraulic oil line, a pilot line, and an electric control system are indicated by double lines, solid lines, dashed lines, and dotted lines, respectively.

The drive system of the excavator 100 includes an engine 11, a regulator 13, a main pump 14, and a control valve 17. As described above, the hydraulic drive system of the excavator 100 includes hydraulic actuators such as the travel hydraulic motors 1L and 1R, the swing hydraulic motor 2A, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 that hydraulically drive the lower travel structure 1, the upper swing structure 3, the boom 4, the arm 5, and the bucket 6, respectively.

The engine 11 is the main power source in the hydraulic drive system, and is mounted, for example, at the rear of the upper rotating body 3. Specifically, the engine 11 rotates at a constant speed at a preset target speed under direct or indirect control by the controller 30 (described later), and drives the main pump 14 and pilot pump 15. The engine 11 is, for example, a diesel engine that uses diesel as fuel.

The regulator 13 controls the discharge volume 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. The regulator 13 includes, for example, regulators 13L and 13R (see FIG. 3), as described below.

The main pump 14 is mounted on the rear of the upper rotating body 3, for example, like the engine 11, and supplies hydraulic oil to the control valve 17 through a high-pressure hydraulic line. 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, and as described above, under the control of the controller 30, the tilt angle of the swash plate is adjusted by the regulator 13 to adjust the stroke length of the piston and control the discharge flow rate (discharge pressure). The main pump 14 includes, for example, main pumps 14L and 14R (see FIG. 3), as described below.

The control valve 17 is, for example, mounted in the center of the upper rotating body 3, and is a hydraulic control device that controls the hydraulic drive system in response to the operation of the operating device 26 by the operator. As described above, the control valve 17 is connected to the main pump 14 via a high-pressure hydraulic line, and selectively supplies hydraulic oil supplied from the main pump 14 to the hydraulic actuators (travel hydraulic motors 1L, 1R, swing hydraulic motor 2A, boom cylinder 7, arm cylinder 8, and bucket cylinder 9) in response to the operating state of the operating device 26. Specifically, the control valve 17 includes control valves 171 to 176 that control the flow rate and flow direction of hydraulic oil supplied from the main pump 14 to each of the hydraulic actuators. More specifically, the control valve 171 corresponds to the travel hydraulic motor 1L, the control valve 172 corresponds to the travel hydraulic motor 1R, and the control valve 173 corresponds to the swing hydraulic motor 2A. Furthermore, control valve 174 corresponds to bucket cylinder 9, control valve 175 corresponds to boom cylinder 7, and control valve 176 corresponds to arm cylinder 8. Furthermore, control valve 175 includes, for example, control valves 175L and 175R (see FIG. 3) as described below, and control valve 176 includes, for example, control valves 176L and 176R (see FIG. 3) as described below. Details of control valves 171 to 176 will be described later.

The operation system of the shovel 100 includes a pilot pump 15 and an operating device 26. The operation system of the shovel 100 also includes a shuttle valve 32 as a component related to the machine control function by the controller 30, which will be described later.

The pilot pump 15 is mounted, for example, at the rear of the upper rotating body 3 and supplies pilot pressure to the operating device 26 via a pilot line. The pilot pump 15 is, for example, a fixed displacement hydraulic pump, and is driven by the engine 11 as described above.

The operation device 26 is provided near the cockpit of the cabin 10, and is an operation input means for the operator to operate various operating elements (lower traveling body 1, upper rotating body 3, boom 4, arm 5, bucket 6, etc.). In other words, the operation device 26 is an operation input means for the operator to operate the hydraulic actuators that drive each operating element (i.e., traveling hydraulic motors 1L, 1R, swing hydraulic motor 2A, boom cylinder 7, arm cylinder 8, bucket cylinder 9, etc.). The operation device 26 is connected to the control valve 17 directly through its secondary pilot line, or indirectly through a shuttle valve 32 (described later) provided in the secondary pilot line. As a result, pilot pressures corresponding to the operating states of the lower traveling body 1, upper rotating body 3, boom 4, arm 5, bucket 6, etc. in the operation device 26 can be input to the control valve 17. Therefore, the control valve 17 can drive each hydraulic actuator according to the operating state in the operation device 26. The operating device 26 includes, for example, a lever device that operates the arm 5 (arm cylinder 8). The operating device 26 also includes, for example, lever devices 26A-26C that operate the boom 4 (boom cylinder 7), bucket 6 (bucket cylinder 9), and upper rotating body 3 (swing hydraulic motor 2A) (see FIG. 4). The operating device 26 also includes, for example, lever devices and pedal devices that operate the pair of left and right crawlers (travel hydraulic motors 1L, 1R) of the lower traveling body 1.

The shuttle valve 32 has two inlet ports and one outlet port, and outputs hydraulic oil having the higher pilot pressure of the two pilot pressures input to the two inlet ports to the outlet port. One of the two inlet ports of the shuttle valve 32 is connected to the operating device 26, and the other is connected to the proportional valve 31. The outlet port of the shuttle valve 32 is connected to the pilot port of the corresponding control valve in the control valve 17 through a pilot line (see FIG. 4 for details). Therefore, the shuttle valve 32 can apply the higher of the pilot pressure generated by the operating device 26 and the pilot pressure generated by the proportional valve 31 to the pilot port of the corresponding control valve. In other words, the controller 30 described later can control the corresponding control valve and control the operation of various operating elements without depending on the operation of the operating device 26 by outputting a pilot pressure higher than the secondary pilot pressure output from the operating device 26 from the proportional valve 31. The shuttle valve 32 includes, for example, shuttle valves 32AL, 32AR, 32BL, 32BR, 32CL, and 32CR (see FIG. 4), as described below.

The operating device 26 may be an electric type that outputs an electric signal, instead of a hydraulic pilot type that outputs a pilot pressure. In this case, the electric signal from the operating device 26 is input to the controller 30, and the controller 30 controls each of the control valves 171 to 176 in the control valve 17 according to the input electric signal, thereby realizing the operation of various hydraulic actuators according to the operation content of the operating device 26. For example, the control valves 171 to 176 in the control valve 17 may be electromagnetic solenoid spool valves that are driven by commands from the controller 30. Also, for example, solenoid valves that operate according to electric signals from the controller 30 may be arranged between the pilot pump 15 and the pilot ports of each of the control valves 171 to 176. In this case, when manual operation is performed using the electric operating device 26, the controller 30 can operate each of the control valves 171 to 176 according to the operation content of the operating device 26 by controlling the solenoid valves by an electric signal corresponding to the operation amount (for example, the lever operation amount) to increase or decrease the pilot pressure.

The control system of the excavator 100 includes a controller 30, a discharge pressure sensor 28, an operating pressure sensor 29, a proportional valve 31, a display device 40, an input device 42, an audio output device 43, a memory device 47, a boom angle sensor S1, an arm angle sensor S2, a bucket angle sensor S3, a machine body inclination sensor S4, a turning state sensor S5, an imaging device S6, a positioning device P1, and a communication device T1.

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

The controller 30 sets the target rotation speed based on, for example, a work mode that is preset by a specific operation by an operator, and performs drive control to rotate the engine 11 at a constant speed.

The controller 30 also outputs a control command to the regulator 13 as necessary, for example, to change the discharge volume of the main pump 14.

The controller 30 also performs control related to a machine guidance function that, for example, guides the operator in manually operating 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 in manually operating the shovel 100 through the operating device 26. In other words, the controller 30 includes a machine guidance unit 50 as a functional unit related to the machine guidance function and the machine control function.

Note that some of the functions of the controller 30 may be realized by other controllers (control devices). That is, the functions of the controller 30 may be realized in a distributed manner by multiple controllers. For example, the machine guidance function and the machine control function may be realized by a dedicated controller (control device).

The discharge pressure sensor 28 detects the discharge pressure of the main pump 14. A detection signal corresponding to the discharge pressure detected by the discharge pressure sensor 28 is input to the controller 30. The discharge pressure sensor 28 includes, for example, discharge pressure sensors 28L and 28R (see FIG. 3), as described below.

As described above, the operating pressure sensor 29 detects the secondary pilot pressure of the operating device 26, that is, the pilot pressure corresponding to the operating state (e.g., the operating contents such as the operating direction and the operating amount) of each operating element (i.e., the hydraulic actuator) in the operating device 26. The detection signal of the pilot pressure corresponding to the operating state of the lower traveling body 1, the upper rotating body 3, the boom 4, the arm 5, the bucket 6, etc. in the operating device 26 by the operating pressure sensor 29 is taken into the controller 30. The operating pressure sensor 29 includes, for example, operating pressure sensors 29A to 29C (see FIG. 4), as described later. Note that, instead of the operating pressure sensor 29, other sensors capable of detecting the operating state of each operating element in the operating device 26, such as an encoder or potentiometer capable of detecting the operating amount (tilt amount) and tilt direction of the lever devices 26A to 26C, may be provided.

The proportional valve 31 is provided in a pilot line connecting the pilot pump 15 and the shuttle valve 32, and is configured so that its flow area (the cross-sectional area through which hydraulic oil can flow) can be changed. The proportional valve 31 operates in response to a control command input from the controller 30. This allows the controller 30 to supply hydraulic oil discharged from the pilot pump 15 to the pilot port of the corresponding control valve in the control valve 17 via the proportional valve 31 and the shuttle valve 32, even when the operating device 26 (specifically, the lever devices 26A to 26C) is not operated by the operator. The proportional valve 31 includes, for example, proportional valves 31AL, 31AR, 31BL, 31BR, 31CL, and 31CR (see FIG. 4), as described below.

The display device 40 is provided in a location that is easily visible to the operator seated in the cabin 10, and displays various information images under the control of the controller 30. The display device 40 may be connected to the controller 30 via an in-vehicle communication network such as a Controller Area Network (CAN), or may be connected to the controller 30 via a one-to-one dedicated line.

The input device 42 is provided within reach of an operator seated in the cabin 10, accepts various operational inputs by the operator, and outputs signals corresponding to the operational inputs to the controller 30. The input device 42 includes a touch panel mounted on the display of a display device that displays various information images, knob switches provided at the tips of the lever portions of the lever devices 26A to 26C, button switches, levers, toggles, rotary dials, etc., that are installed around the display device 40. Signals corresponding to the operations performed on the input device 42 are input to the controller 30.

The audio output device 43 is provided, for example, in the cabin 10, connected to the controller 30, and outputs audio under the control of the controller 30. The audio output device 43 is, for example, a speaker or a buzzer. The audio output device 43 outputs various information by audio in response to an audio output command from the controller 30.

The storage device 47 is provided, for example, in the cabin 10, and stores various information under the control of the controller 30. The storage device 47 is, for example, a non-volatile storage medium such as a semiconductor memory. The storage device 47 may store information output by various devices during operation of the shovel 100, or may store information acquired via various devices before operation of the shovel 100 is started. The storage device 47 may store data related to a target construction surface acquired, for example, via a communication device T1, or set via an input device 42, or the like. The target construction surface may be set (saved) by the operator of the shovel 100, or may be set by a construction manager, or the like.

The boom angle sensor S1 is attached to the boom 4 and detects the elevation angle of the boom 4 relative to the upper rotating body 3 (hereinafter referred to as the "boom angle"), for example, the angle formed by a straight line connecting the fulcrums at both ends of the boom 4 relative to the rotation plane of the upper rotating body 3 in a side view. The boom angle sensor S1 may include, for example, a rotary encoder, an acceleration sensor, a six-axis sensor, an IMU (Inertial Measurement Unit), etc. The boom angle sensor S1 may also include a potentiometer using a variable resistor, a cylinder sensor that detects the stroke amount of a hydraulic cylinder (boom cylinder 7) corresponding to the boom angle, etc. The same applies to the arm angle sensor S2 and bucket angle sensor S3 below. The detection signal corresponding to the boom angle by the boom angle sensor S1 is taken into the controller 30.

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

The bucket angle sensor S3 is attached to the bucket 6 and detects the rotation angle of the bucket 6 relative to the arm 5 (hereinafter referred to as the "bucket angle"), for example, the angle formed by a line connecting the fulcrums at both ends of the arm 5 and a line connecting the fulcrum and tip (cutting edge) of the bucket 6 in a side view. A detection signal corresponding to the bucket angle by the bucket angle sensor S3 is input to the controller 30.

The machine body inclination sensor S4 detects the inclination state of the machine body (upper rotating body 3 or lower running body 1) relative to the horizontal plane. The machine body inclination sensor S4 is attached, for example, to the upper rotating body 3, and detects the inclination angle around two axes in the forward/backward and left/right directions (hereinafter referred to as the "forward/rearward inclination angle" and the "left/right inclination angle") of the shovel 100 (i.e., the upper rotating body 3). The machine body inclination sensor S4 may include, for example, a rotary encoder, an acceleration sensor, a six-axis sensor, an IMU, etc. The detection signal corresponding to the inclination angle (forward/backward inclination angle and left/right inclination angle) by the machine body inclination sensor S4 is input to the controller 30.

The rotation state sensor S5 outputs detection information regarding the rotation state of the upper rotating body 3. The rotation state sensor S5 detects, for example, the rotation angular velocity and rotation angle of the upper rotating body 3. The rotation state sensor S5 may include, for example, a gyro sensor, a resolver, a rotary encoder, etc. The detection signal corresponding to the rotation angle and rotation angular velocity of the upper rotating body 3 by the rotation state sensor S5 is input to the controller 30.

The imaging device S6 captures images of the periphery of the shovel 100. The imaging device S6 includes a camera S6F that captures images in front of the shovel 100, a camera S6L that captures images to the left of the shovel 100, a camera S6R that captures images to the right of the shovel 100, and a camera S6B that captures images behind the shovel 100.

Camera S6F is attached, for example, to the ceiling of cabin 10, i.e., inside cabin 10. Camera S6F may also be attached to the outside of cabin 10, such as the roof of cabin 10 or the side of boom 4. Camera S6L is attached to the left end of the top surface of upper rotating body 3, camera S6R is attached to the right end of the top surface of upper rotating body 3, and camera S6B is attached to the rear end of the top surface of upper rotating body 3.

Each of the imaging devices S6 (cameras S6F, S6B, S6L, and S6R) is, for example, a monocular wide-angle camera with a very wide angle of view. The imaging device S6 may also be a stereo camera or a distance imaging camera. Images captured by the imaging device S6 are input to the controller 30 via the display device 40.

The imaging device S6 may also function as an object detection device. In this case, the imaging device S6 may detect objects present around the shovel 100. The objects to be detected may include, for example, people, animals, vehicles, construction machinery, buildings, holes, etc. The imaging device S6 may also calculate the distance from the imaging device S6 or the shovel 100 to the recognized object. The imaging device S6 as an object detection device may include, for example, a stereo camera, a distance image sensor, etc. In addition to the imaging device S6, other object detection devices such as an ultrasonic sensor, a millimeter wave radar, a LIDAR, an infrared sensor, etc. may also be provided.

The imaging device S6 may also be directly connected to the controller 30 so as to be able to communicate with it.

The positioning device P1 measures the position and orientation of the upper rotating body 3. The positioning device P1 is, for example, a Global Navigation Satellite System (GNSS) compass, which 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. In addition, the function of detecting the orientation of the upper rotating body 3, which is one of the functions of the positioning device P1, may be replaced by a direction sensor attached to the upper rotating body 3.

The communication device T1 communicates with external devices through a predetermined network including a mobile communication network with a base station as an end, a satellite communication network, the Internet, etc. The communication device T1 is, for example, a mobile communication module compatible with 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.

The machine guidance unit 50, for example, executes control of the excavator 100 regarding the machine guidance function. The machine guidance unit 50 conveys work information, such as the distance between the target construction surface and the tip of the attachment, specifically, the working part of the end attachment, to the operator through the display device 40, the audio output device 43, etc. Data regarding the target construction surface is, for example, stored in advance in the storage device 47 as described above. Data regarding the target construction surface is, for example, expressed in a reference coordinate system. The reference coordinate system is, for example, the World Geodetic System. The World Geodetic System is a three-dimensional orthogonal XYZ coordinate system with the origin at the center of gravity of the earth, the X axis in the direction of the intersection of the Greenwich meridian and the equator, the Y axis in the direction of 90 degrees east longitude, and the Z axis in the direction of the North Pole. The operator may set any point on the construction site as a reference point and set the target construction surface through the input device 42 based on the relative positional relationship with the reference point. The working part of the bucket 6 is, for example, the tip of the bucket 6, the back of the bucket 6, etc. Also, if, for example, a breaker is used as the end attachment instead of the bucket 6, the tip of the breaker corresponds to the working part. The machine guidance unit 50 notifies the operator of work information via the display device 40, the audio output device 43, etc., and guides the operator in operating the excavator 100 via the operating device 26.

The machine guidance unit 50 also controls the excavator 100, for example, with respect to the machine control function. For example, when an operator is manually performing an excavation operation, the machine guidance unit 50 may automatically operate at least one of the boom 4, the arm 5, and the bucket 6 so that the tip position of the bucket 6 coincides with a target trajectory (for example, a target construction surface, etc.).

The machine guidance unit 50 acquires information from the boom angle sensor S1, arm angle sensor S2, bucket angle sensor S3, machine body inclination sensor S4, turning state sensor S5, imaging device S6, positioning device P1, communication device T1, input device 42, etc. Then, the machine guidance unit 50 calculates the distance between the bucket 6 and the target construction surface based on the acquired information, notifies the operator of the degree of the distance between the bucket 6 and the target construction surface by voice from the voice output device 43 and an image displayed on the display device 40, and automatically controls the operation of the attachment so that the tip of the attachment (specifically, the working part such as the tip or back of the bucket 6) coincides with the target construction surface. The machine guidance unit 50 includes a position calculation unit 51, a distance calculation unit 52, an information transmission unit 53, and an automatic control unit 54 as detailed functional configurations related to the machine guidance function and the machine control function.

The position calculation unit 51 calculates the position of a predetermined positioning target. For example, the position calculation unit 51 calculates the coordinate point in a reference coordinate system of the tip of the attachment, specifically, the working part such as the tip or back of the bucket 6. Specifically, the position calculation unit 51 calculates the coordinate point of the working part of the bucket 6 from the respective elevation and depression angles of the boom 4, arm 5, and bucket 6 (boom angle, arm angle, and bucket angle).

The distance calculation unit 52 calculates the distance between two positioning targets. For example, the distance calculation unit 52 calculates the distance between the tip of the attachment, specifically, the working part such as the tip or back of the bucket 6, and the target construction surface. The distance calculation unit 52 may also calculate the angle (relative angle) between the back of the bucket 6 as the working part and the target construction surface.

The information transmission unit 53 transmits (notifies) various information to the operator of the shovel 100 through a predetermined notification means such as the display device 40 or the audio output device 43. The information transmission unit 53 notifies the operator of the shovel 100 of the magnitude (degree) of various distances calculated by the distance calculation unit 52. For example, the information transmission unit 53 notifies the operator of the distance (magnitude) between the tip of the bucket 6 and the target construction surface using at least one of visual information from the display device 40 and audio information from the audio output device 43. The information transmission unit 53 may also notify the operator of the relative angle (magnitude) between the back of the bucket 6 as the working part and the target construction surface using at least one of visual information from the display device 40 and audio information from the audio output device 43.

Specifically, the information transmission unit 53 uses intermittent sounds from the audio output device 43 to inform the operator of the distance (e.g., vertical distance) between the working portion of the bucket 6 and the target construction surface. In this case, the information transmission unit 53 may shorten the interval of the intermittent sounds as the vertical distance decreases, and may lengthen the interval of the intermittent sounds as the vertical distance increases. The information transmission unit 53 may also use a continuous sound, or may express differences in the vertical distance by varying the pitch, strength, etc. of the sound. The information transmission unit 53 may also issue an alarm through the audio output device 43 when the tip of the bucket 6 is lower than the target construction surface, that is, when it has passed the target construction surface. The alarm is, for example, a continuous sound that is significantly louder than the intermittent sound.

The information transmission unit 53 may also cause the display device 40 to display, as work information, the distance between the tip of the attachment, specifically the working part of the bucket 6, and the target construction surface, and the relative angle between the back surface of the bucket 6 and the target construction surface. Under the control of the controller 30, the display device 40 displays the work information received from the information transmission unit 53 together with, for example, image data received from the imaging device S6. The information transmission unit 53 may convey the vertical distance to the operator using, for example, an image of an analog meter or an image of a bar graph indicator.

The automatic control unit 54 automatically assists the operator in manually operating the excavator 100 through the operation device 26 by automatically operating the actuators. Specifically, the automatic control unit 54 can individually and automatically adjust the pilot pressure acting on the control valves (specifically, the control valves 173, 175L, 175R, and 174) corresponding to the multiple hydraulic actuators (specifically, the swing hydraulic motor 2A, the boom cylinder 7, and the bucket cylinder 9), as described below. This allows the automatic control unit 54 to automatically operate each hydraulic actuator. The control of the machine control function by the automatic control unit 54 may be performed, for example, when a predetermined switch included in the input device 42 is pressed. The predetermined switch may be, for example, a machine control switch (hereinafter referred to as an "MC (Machine Control) switch"), and may be disposed as a knob switch at the tip of the operator's grip of the operation device 26 (for example, a lever device corresponding to the operation of the arm 5). The following description will be given on the assumption that the machine control function is active when the MC switch is pressed.

For example, when an MC switch or the like is pressed, the automatic control unit 54 automatically extends and retracts at least one of the boom cylinder 7 and the bucket cylinder 9 in accordance with the operation of the arm cylinder 8 to support excavation and shaping work. Specifically, when an operator manually performs a closing operation of the arm 5 (hereinafter referred to as an "arm closing operation"), the automatic control unit 54 automatically extends and retracts at least one of the boom cylinder 7 and the bucket cylinder 9 so that the target construction surface coincides with the position of the work part, such as the tip or back of the bucket 6. In this case, the operator can close the arm 5 while aligning the tip of the bucket 6, etc. with the target construction surface, simply by performing an arm closing operation on a lever device corresponding to the operation of the arm 5, for example.

[Excavator hydraulic system]
Next, a hydraulic system of the shovel 100 according to one embodiment will be described with reference to Fig. 3. Fig. 3 is a diagram showing an example of the configuration of the hydraulic system of the shovel 100 according to one embodiment. In Fig. 3, a mechanical power system, a hydraulic oil line, a pilot line, and an electrical control system are indicated by double lines, solid lines, dashed lines, and dotted lines, respectively.

The hydraulic system realized by the hydraulic circuit shown in FIG. 3 circulates hydraulic oil from each of the main pumps 14L, 14R driven by the engine 11 through center bypass oil passages 40L, 40R and parallel oil passages 42L, 42R to the hydraulic oil tank.

The center bypass oil passage 40L starts at the main pump 14L, passes through the control valves 171, 173, 175L, and 176L arranged in the control valve 17, and then reaches the hydraulic oil tank.

The center bypass oil passage 40R starts at the main pump 14R, passes through the control valves 172, 174, 175R, and 176R arranged in the control valve 17, and reaches the hydraulic oil tank.

The control valve 171 is a spool valve that supplies hydraulic oil discharged from the main pump 14L to the travel hydraulic motor 1L and discharges hydraulic oil discharged by the travel hydraulic motor 1L into the hydraulic oil tank.

The control valve 172 is a spool valve that supplies hydraulic oil discharged from the main pump 14R to the traveling hydraulic motor 1R and discharges hydraulic oil discharged by the traveling hydraulic motor 1R to the hydraulic oil tank.

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

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

The control valves 175L and 175R are spool valves that supply hydraulic oil discharged from the main pumps 14L and 14R to the boom cylinder 7, and discharge the hydraulic oil in the boom cylinder 7 to the hydraulic oil tank.

The control valves 176L and 176R supply hydraulic oil discharged from the main pumps 14L and 14R to the arm cylinder 8, and also discharge the hydraulic oil in the arm cylinder 8 to the hydraulic oil tank.

Control valves 171, 172, 173, 174, 175L, 175R, 176L, and 176R adjust the flow rate and switch the flow direction of hydraulic oil supplied to and discharged from the hydraulic actuator according to the pilot pressure acting on the respective pilot ports.

The parallel oil passage 42L supplies hydraulic oil of the main pump 14L to the control valves 171, 173, 175L, and 176L in parallel with the center bypass oil passage 40L. Specifically, the parallel oil passage 42L branches off from the center bypass oil passage 40L upstream of the control valve 171, and is configured to be able to supply hydraulic oil of the main pump 14L in parallel to each of the control valves 171, 173, 175L, and 176L. As a result, the parallel oil passage 42L can supply hydraulic oil to a more downstream control valve when the flow of hydraulic oil through the center bypass oil passage 40L is restricted or blocked by any of the control valves 171, 173, and 175L.

The parallel oil passage 42R supplies hydraulic oil of the main pump 14R to the control valves 172, 174, 175R, and 176R in parallel with the center bypass oil passage 40R. Specifically, the parallel oil passage 42R branches off from the center bypass oil passage 40R upstream of the control valve 172, and is configured to be able to supply hydraulic oil of the main pump 14R in parallel to each of the control valves 172, 174, 175R, and 176R. As a result, the parallel oil passage 42R can supply hydraulic oil to a more downstream control valve when the flow of hydraulic oil through the center bypass oil passage 40R is restricted or blocked by any of the control valves 172, 174, and 175R.

Regulators 13L and 13R adjust the discharge volume of main pumps 14L and 14R by adjusting the tilt angle of the swash plates of main pumps 14L and 14R under the control of controller 30.

The discharge pressure sensor 28L detects the discharge pressure of the main pump 14L, and a detection signal corresponding to the detected discharge pressure is input to the controller 30. The same is true for the discharge pressure sensor 28R. This allows the controller 30 to control the regulators 13L and 13R according to the discharge pressures of the main pumps 14L and 14R.

Negative control throttles (hereafter referred to as "negative control throttles") 18L, 18R are provided in the center bypass oil passages 40L, 40R between the hydraulic oil tank and the most downstream control valves 176L, 176R, respectively. As a result, the flow of hydraulic oil discharged by the main pumps 14L, 14R is restricted by the negative control throttles 18L, 18R. The negative control throttles 18L, 18R then generate a control pressure (hereafter referred to as "negative control pressure") for controlling the regulators 13L, 13R.

Negative control pressure sensors 19L and 19R detect the negative control pressure, and the detection signal corresponding to the detected negative control pressure is input to controller 30.

The controller 30 may control the regulators 13L, 13R in response to the discharge pressure of the main pumps 14L, 14R detected by the discharge pressure sensors 28L, 28R to adjust the discharge volume of the main pumps 14L, 14R. For example, the controller 30 may control the regulator 13L in response to an increase in the discharge pressure of the main pump 14L, and reduce the discharge volume by adjusting the swash plate tilt angle of the main pump 14L. The same applies to the regulator 13R. This allows the controller 30 to control the total horsepower of the main pumps 14L, 14R so that the absorption horsepower of the main pumps 14L, 14R, which is expressed as the product of the discharge pressure and the discharge volume, does not exceed the output horsepower of the engine 11.

The controller 30 may also adjust the discharge rate of the main pumps 14L, 14R by controlling the regulators 13L, 13R according to the negative control pressure detected by the negative control pressure sensors 19L, 19R. For example, the controller 30 decreases the discharge rate of the main pumps 14L, 14R as the negative control pressure increases, and increases the discharge rate of the main pumps 14L, 14R as the negative control pressure decreases.

Specifically, when the excavator 100 is in a standby state in which none of the hydraulic actuators are being operated, the hydraulic oil discharged from the main pumps 14L, 14R passes through the center bypass oil passages 40L, 40R to the negative control throttles 18L, 18R. The flow of hydraulic oil discharged from the main pumps 14L, 14R increases the negative control pressure generated upstream of the negative control throttles 18L, 18R. As a result, the controller 30 reduces the discharge rate of the main pumps 14L, 14R to the minimum allowable discharge rate, suppressing pressure loss (pumping loss) when the discharged hydraulic oil passes through the center bypass oil passages 40L, 40R.

On the other hand, when any of the hydraulic actuators is operated through the operating device 26, the hydraulic oil discharged from the main pumps 14L, 14R flows into the hydraulic actuator to be operated through the control valve corresponding to the hydraulic actuator to be operated. The flow of hydraulic oil discharged from the main pumps 14L, 14R reduces or eliminates the amount of hydraulic oil reaching the negative control throttles 18L, 18R, lowering the negative control pressure generated upstream of the negative control throttles 18L, 18R. As a result, the controller 30 increases the discharge amount of the main pumps 14L, 14R, circulates sufficient hydraulic oil to the hydraulic actuator to be operated, and can reliably drive the hydraulic actuator to be operated.

[Details of configuration regarding excavator machine control function]
Next, the details of the configuration related to the machine control function of the excavator 100 will be described with reference to Fig. 4. Fig. 4 is a diagram showing an example of a component part of an operation system in a hydraulic system of the excavator 100 of one embodiment. Specifically, Fig. 4(A) is a diagram showing an example of a pilot circuit that applies pilot pressure to control valves 175L, 175R that hydraulically control the boom cylinder 7. Fig. 4(B) is a diagram showing an example of a pilot circuit that applies pilot pressure to a control valve 174 that hydraulically controls the bucket cylinder 9. Fig. 4(C) is a diagram showing an example of a pilot circuit that applies pilot pressure to a control valve 173 that hydraulically controls the swing hydraulic motor 2A.

As shown in FIG. 4(A), the lever device 26A is used by an operator to operate the boom cylinder 7 corresponding to the boom 4. The lever device 26A uses hydraulic oil discharged from the pilot pump 15 to output pilot pressure to the secondary side according to the operation content.

The shuttle valve 32AL has two inlet ports connected to the secondary pilot line of the lever device 26A, which corresponds to the operation of the boom 4 in the lifting direction (hereinafter referred to as the "boom lifting operation"), and the secondary pilot line of the proportional valve 31AL, and an outlet port connected to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R.

The shuttle valve 32AR has two inlet ports connected to the secondary pilot line of the lever device 26A, which corresponds to the operation of lowering the boom 4 (hereinafter referred to as the "boom lowering operation"), and the secondary pilot line of the proportional valve 31AR, and an outlet port connected to the right pilot port of the control valve 175R.

That is, the lever device 26A applies pilot pressure corresponding to the operation content (e.g., the operation direction and the operation amount) to the pilot ports of the control valves 175L and 175R via the shuttle valves 32AL and 32AR. Specifically, when the boom is raised, the lever device 26A outputs pilot pressure corresponding to the operation amount to one inlet port of the shuttle valve 32AL, and applies it to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the shuttle valve 32AL. Also, when the boom is lowered, the lever device 26A outputs pilot pressure corresponding to the operation amount to one inlet port of the shuttle valve 32AR, and applies it to the right pilot port of the control valve 175R via the shuttle valve 32AR.

The proportional valve 31AL operates in response to a control current input from the controller 30. Specifically, the proportional valve 31AL uses hydraulic oil discharged from the pilot pump 15 to output a pilot pressure corresponding to the control current input from the controller 30 to the other inlet port of the shuttle valve 32AL. This allows the proportional valve 31AL to adjust the pilot pressure acting on the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the shuttle valve 32AL.

The proportional valve 31AR operates according to the control current input from the controller 30. Specifically, the proportional valve 31AR uses the hydraulic oil discharged from the pilot pump 15 to output a pilot pressure according to the control current input from the controller 30 to the other inlet port of the shuttle valve 32AR. This allows the proportional valve 31AR to adjust the pilot pressure acting on the right pilot port of the control valve 175R via the shuttle valve 32AR.

In other words, the proportional valves 31AL and 31AR can adjust the pilot pressure output to the secondary side so that the control valves 175L and 175R can be stopped at any valve position, regardless of the operating state of the lever device 26A.

The operating pressure sensor 29A detects the operation of the lever device 26A by the operator in the form of pressure (operating pressure), and a detection signal corresponding to the detected pressure is input to the controller 30. This allows the controller 30 to grasp the operation of the lever device 26A.

The controller 30 can supply hydraulic 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 proportional valve 31AL and the shuttle valve 32AL, regardless of the boom-raising operation of the lever device 26A by the operator. Also, the controller 30 can supply hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 175R via the proportional valve 31AR and the shuttle valve 32AR, regardless of the boom-lowering operation of the lever device 26A by the operator. In other words, the controller 30 can automatically control the raising and lowering operation of the boom 4.

As shown in FIG. 4B, the lever device 26B is used by an operator to operate the bucket cylinder 9 corresponding to the bucket 6. The lever device 26B uses the hydraulic oil discharged from the pilot pump 15 to output pilot pressure to the secondary side according to the operation.

The shuttle valve 32BL has two inlet ports connected to the secondary pilot line of the lever device 26B, which corresponds to the operation in the closing direction of the bucket 6 (hereinafter referred to as the "bucket closing operation"), and the secondary pilot line of the proportional valve 31BL, and an outlet port connected to the left pilot port of the control valve 174.

The shuttle valve 32BR has two inlet ports connected to the secondary pilot line of the lever device 26B, which corresponds to the operation of the bucket 6 in the opening direction (hereinafter referred to as the "bucket opening operation"), and the secondary pilot line of the proportional valve 31BR, and an outlet port connected to the right pilot port of the control valve 174.

In other words, the lever device 26B applies pilot pressure according to the operation to the pilot port of the control valve 174 via the shuttle valves 32BL and 32BR. Specifically, when the bucket is closed, the lever device 26B outputs pilot pressure according to the operation amount to one inlet port of the shuttle valve 32BL, and applies it to the left pilot port of the control valve 174 via the shuttle valve 32BL. Also, when the bucket is opened, the lever device 26B outputs pilot pressure according to the operation amount to one inlet port of the shuttle valve 32BR, and applies it to the right pilot port of the control valve 174 via the shuttle valve 32BR.

The proportional valve 31BL operates in response to the control current input from the controller 30. Specifically, the proportional valve 31BL uses the hydraulic oil discharged from the pilot pump 15 to output a pilot pressure corresponding to the control current input from the controller 30 to the other pilot port of the shuttle valve 32BL. This allows the proportional valve 31BL to adjust the pilot pressure acting on the left pilot port of the control valve 174 via the shuttle valve 32BL.

The proportional valve 31BR operates in response to the control current input from the controller 30. Specifically, the proportional valve 31BR uses the hydraulic oil discharged from the pilot pump 15 to output a pilot pressure corresponding to the control current input from the controller 30 to the other pilot port of the shuttle valve 32BR. This allows the proportional valve 31BR to adjust the pilot pressure acting on the right pilot port of the control valve 174 via the shuttle valve 32BR.

In other words, the proportional valves 31BL and 31BR can adjust the pilot pressure output to the secondary side so that the control valve 174 can be stopped at any valve position, regardless of the operating state of the lever device 26B.

The operating pressure sensor 29B detects the operation of the lever device 26B by the operator in the form of pressure (operating pressure), and a detection signal corresponding to the detected pressure is input to the controller 30. This allows the controller 30 to grasp the operation of the lever device 26B.

The controller 30 can supply hydraulic oil discharged from the pilot pump 15 to the left pilot port of the control valve 174 via the proportional valve 31BL and the shuttle valve 32BL, regardless of the bucket closing operation of the operator using the lever device 26B. The controller 30 can also supply hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 174 via the proportional valve 31BR and the shuttle valve 32BR, regardless of the bucket opening operation of the operator using the lever device 26B. In other words, the controller 30 can automatically control the opening and closing operation of the bucket 6.

As shown in FIG. 4(C), the lever device 26C is used by an operator to operate the swing hydraulic motor 2A corresponding to the upper swing body 3 (swing mechanism 2). The lever device 26C uses the hydraulic oil discharged from the pilot pump 15 to output pilot pressure to the secondary side according to the operation content.

The shuttle valve 32CL has two inlet ports connected to the secondary pilot line of the lever device 26C corresponding to the leftward rotation operation of the upper rotating body 3 (hereinafter referred to as the "left rotation operation") and the secondary pilot line of the proportional valve 31CL, and an outlet port connected to the left pilot port of the control valve 173.

The shuttle valve 32CR has two inlet ports connected to the secondary pilot line of the lever device 26C corresponding to the rightward rotation operation of the upper rotating body 3 (hereinafter referred to as the "right rotation operation") and the secondary pilot line of the proportional valve 31CR, and an outlet port connected to the right pilot port of the control valve 173.

In other words, the lever device 26C applies pilot pressure corresponding to the operation in the left and right direction to the pilot port of the control valve 173 via the shuttle valves 32CL and 32CR. Specifically, when the lever device 26C is operated to turn left, it outputs pilot pressure corresponding to the operation amount to one inlet port of the shuttle valve 32CL, and applies it to the left pilot port of the control valve 173 via the shuttle valve 32CL. Also, when the lever device 26C is operated to turn right, it outputs pilot pressure corresponding to the operation amount to one inlet port of the shuttle valve 32CR, and applies it to the right pilot port of the control valve 173 via the shuttle valve 32CR.

The proportional valve 31CL operates in response to the control current input from the controller 30. Specifically, the proportional valve 31CL uses the hydraulic oil discharged from the pilot pump 15 to output a pilot pressure corresponding to the control current input from the controller 30 to the other pilot port of the shuttle valve 32CL. This allows the proportional valve 31CL to adjust the pilot pressure acting on the left pilot port of the control valve 173 via the shuttle valve 32CL.

The proportional valve 31CR operates in response to the control current input from the controller 30. Specifically, the proportional valve 31CR uses the hydraulic oil discharged from the pilot pump 15 to output a pilot pressure corresponding to the control current input from the controller 30 to the other pilot port of the shuttle valve 32CR. This allows the proportional valve 31CR to adjust the pilot pressure acting on the right pilot port of the control valve 173 via the shuttle valve 32CR.

In other words, the proportional valves 31CL and 31CR can adjust the pilot pressure output to the secondary side so that the control valve 173 can be stopped at any valve position, regardless of the operating state of the lever device 26C.

The operating pressure sensor 29C detects the operating state of the lever device 26C by the operator as pressure, and a detection signal corresponding to the detected pressure is input to the controller 30. This allows the controller 30 to grasp the operation content of the lever device 26C in the left and right directions.

The controller 30 can supply hydraulic oil discharged from the pilot pump 15 to the left pilot port of the control valve 173 via the proportional valve 31CL and the shuttle valve 32CL, regardless of the left rotation operation of the lever device 26C by the operator. The controller 30 can also supply hydraulic oil discharged from the pilot pump 15 to the right pilot port of the control valve 173 via the proportional valve 31CR and the shuttle valve 32CR, regardless of the right rotation operation of the lever device 26C by the operator. In other words, the controller 30 can automatically control the left-right rotation operation of the upper rotating body 3.

The excavator 100 may further include a configuration for automatically opening and closing the arm 5, and a configuration for automatically moving the lower traveling structure 1 forward and backward. In this case, the components of the hydraulic system related to the operation system of the arm cylinder 8, the components related to the operation system of the traveling hydraulic motor 1L, and the components related to the operation of the traveling hydraulic motor 1R may be configured similarly to the components related to the operation system of the boom cylinder 7, etc. (Figures 4 (A) to (C)).

[Shovel operation]
Next, an excavation and loading operation will be described with reference to Fig. 5 as an example of the operation of the shovel 100. Fig. 5 is a diagram for explaining the excavation and loading operation.

First, as shown in FIG. 5(a), with the upper rotating body 3 rotated so that the bucket 6 is positioned above the excavation position, and with the arm 5 and bucket 6 open, the operator lowers the boom 4 and lowers the bucket 6 so that the tip of the bucket 6 is at the target excavation depth D. Normally, the operator controls the rotation and boom lowering and visually confirms the position of the bucket 6. It is also common to rotate the upper rotating body 3 and lower the boom 4 simultaneously. The above operation is called the boom lowering rotation operation, and this operation section is called the boom lowering rotation operation section.

When the operator determines that the tip of the bucket 6 has reached the target excavation depth D, the operator then moves to a horizontal pulling operation as shown in FIG. 5(b). In the horizontal pulling operation, the arm 5 is closed until it is perpendicular to the ground so that the tip of the bucket 6 moves almost horizontally. This horizontal pulling operation excavates soil to a specified depth and rakes it up with the bucket 6. Once the horizontal pulling operation is complete, the bucket 6 is then closed until it is at 90 degrees to the arm 5 as shown in FIG. 5(c). In other words, the bucket 6 is closed until the upper edge of the bucket 6 is horizontal, and the raked up soil is stored in the bucket 6. The above operation is called the excavation operation, and this operation section is called the excavation operation section.

When the operator determines that the bucket 6 has been closed to 90 degrees, he or she then raises the boom 4 with the bucket 6 closed until the bottom of the bucket 6 reaches a predetermined height H, as shown in FIG. 5(d). Following this, or at the same time, the upper rotating body 3 is rotated to rotate the bucket 6 to a position from which soil will be discharged. The above operation is called the boom-raising and rotating operation, and this operation section is called the boom-raising and rotating operation section.

The boom 4 is raised until the bottom of the bucket 6 reaches a predetermined height H because, for example, when dumping soil onto the bed of a dump truck, the bucket 6 must be raised higher than the height of the bed, otherwise it will hit the bed. For example, if an inexperienced operator is operating the machine, there is a risk that the bucket 6 will turn without being raised to the predetermined height H. In such a case, there is a risk that the bucket 6 will hit the bed of the dump truck.

When the operator determines that the boom raising and rotating operation is complete, he or she then opens the arm 5 and bucket 6 as shown in FIG. 5(e) to discharge the soil in the bucket 6. This operation is called the dump operation, and this operation section is called the dump operation section. In the dump operation, only the bucket 6 may be opened to discharge the soil.

When the operator determines that the dumping operation is complete, he or she then rotates the upper rotating body 3 to move the bucket 6 directly above the excavation position, as shown in FIG. 5(f). At this time, the boom 4 is lowered at the same time as the rotation, and the bucket 6 is lowered to the excavation start position. This operation is part of the boom lowering and rotating operation described in FIG. 5(a). The operator lowers the bucket 6 from the excavation start position to the target excavation depth D, as shown in FIG. 5(a), and again performs the excavation operation shown in FIG. 5(b).

The above "boom lowering and rotating operation", "digging operation", "boom raising and rotating operation", "dumping operation", and "boom lowering and rotating operation" form one cycle, and this cycle is repeated to proceed with excavation and loading.

[Scooping process]
Next, with reference to Figures 6 and 7, a control process (hereinafter referred to as "scooping process") in which the controller 30 (automatic control unit 54) automatically operates the actuator to scoop up soil while monitoring the state of soil on the opening side (excavation direction) of the bucket 6 during the above-mentioned excavation operation will be described. Figure 6 is a flowchart showing an example of the scooping process. Figure 7 is a diagram showing parameters used for judgment in the scooping process.

The scooping process according to the flowchart in FIG. 6 is repeatedly executed at a predetermined processing cycle, for example, when the MC switch or the like is pressed and a horizontal pulling operation or an excavation operation is being performed. The bucket 6 moves along the generated target trajectory 700.

When a horizontal pulling operation or an excavation operation is performed, the movement of the bucket 6 pushes up the ground surface and the soil underground. As a result, a pile of soil 702 is formed on the opening side of the bucket 6. The pile of soil 702 grows larger as the bucket 6 moves during the excavation operation.

In step ST61, the automatic control unit 54 determines whether the angle β of the pile of soil 702 with respect to the horizontal plane, which is one of the conditions of the soil on the opening side (traveling direction side) of the bucket 6, is equal to or greater than a predetermined angle. The angle β is the angle of the slope of the bucket 6 side of the pile of soil 702 on the opening side of the bucket 6 with respect to the horizontal plane V, as shown in FIG. 7, for example. The angle β may be, for example, the angle of the straight line connecting the position A1 corresponding to the upper edge 6a of the bucket 6 on the slope of the pile of soil 702 with the top A2 of the pile of soil 702 with respect to the horizontal plane V. The angle β may be calculated, for example, by the controller 30 capturing an image captured by the imaging device S6, or may be calculated by the imaging device S6. The predetermined angle is preferably determined according to the angle of repose of the soil, and may be, for example, the angle of repose of the soil. If the predetermined angle is the angle of repose of the soil, the soil will naturally fall toward the back of the bucket 6 even if the pile of soil 702 grows large due to the subsequent movement of the bucket 6. In this way, the soil naturally penetrates deep into the bucket 6, allowing efficient excavation. If the angle β is smaller than the predetermined angle, the automatic control unit 54 determines that the development of the soil pile 702 is insufficient, executes the process of step ST61 again, and continues moving the bucket 6. If the angle β is equal to or greater than the predetermined angle, the bucket 6 continues to move while the judgment process proceeds to step ST62. When the angle β of the soil pile 702 becomes equal to or greater than the predetermined angle, the soil pile 702 continues to grow while maintaining that angle. The soil then penetrates deep into the bucket 6 as it collapses.

In step ST62, the automatic control unit 54 determines whether the amount of soil loaded into the bucket 6, which is one of the conditions of the soil on the opening side of the bucket 6, is equal to or greater than a predetermined amount. Specifically, the automatic control unit 54 determines whether the length L from the base end 6b of the bucket 6 to a position A1 corresponding to the slope of the soil pile 702 at the upper edge 6a of the bucket 6 is equal to or less than a predetermined length, as shown in FIG. 7 for example. The length L may be calculated by the controller 30 capturing an image captured by the imaging device S6, or may be calculated by the imaging device S6. The predetermined length is preferably approximately 1/3 of the length of the upper edge 6a of the bucket 6. When the predetermined length is approximately 1/3 of the length of the upper edge 6a of the bucket 6, it can be determined that the soil has penetrated to the back of the bucket 6. When the length L is greater than the predetermined length, the automatic control unit 54 executes the process of step ST62 again, and when the length L is equal to or less than the predetermined length, the process proceeds to step ST63. If the bucket 6 continues to move after that, the pile of dirt 702 will continue to grow.

In step ST63, the automatic control unit 54 determines whether the height H of the pile of dirt 702 relative to the ground 701, which is one of the conditions of the dirt on the opening side of the bucket 6, is equal to or greater than a predetermined height. The height H is the height of the top A2 of the pile of dirt 702 relative to the ground 701, as shown in FIG. 7, for example. The height H may be calculated, for example, by the controller 30 capturing an image captured by the imaging device S6, or may be calculated by the imaging device S6. The predetermined height is preferably the height of the base end 6b of the bucket 6. When the predetermined height is the height of the base end 6b of the bucket 6, when the bucket 6 is closed until the upper edge 6a of the bucket 6 becomes approximately horizontal and the collected dirt is stored in the bucket 6, a lot of dirt enters the bucket 6, so that the dirt can be efficiently scooped up. If the height H is smaller than the predetermined height, the automatic control unit 54 executes the process of step ST63 again, and if the height H is equal to or greater than the predetermined height, it determines that the pile of dirt 702 has grown sufficiently and proceeds to step ST64.

In step ST64, the automatic control unit 54 executes an operation to scoop up the bucket 6 (hereinafter referred to as the "scooping operation"). The scooping operation may be, for example, an operation to close the bucket 6 until the upper edge 6a of the bucket 6 becomes approximately horizontal, and to control the attachment so that the back surface 6c of the bucket 6 is moved away from the excavation surface (the ground surface 701 and the pile of dirt 702).

In this way, in one embodiment of the excavator 100, when, for example, an MC switch or the like is pressed and a horizontal pulling operation or an excavation operation is being performed, the controller 30 (automatic control unit 54) automatically operates the actuator to perform the scooping process. Then, in the scooping process, the controller 30 (automatic control unit 54) controls the excavation operation of the attachment taking into account the condition of the soil. This allows the soil to be scooped up efficiently. Therefore, the soil that accumulates in front of the bucket 6 during the excavation operation can be reduced. As a result, the work required to remove the soil that accumulates in front of the bucket 6 is reduced, improving work efficiency.

The judgment process can be changed depending on the bucket size and soil characteristics. For example, the order of steps ST62 and ST63 may be switched. Furthermore, at least one of steps ST62 and ST63 may be the judgment process. Furthermore, the judgment of step ST61 is not necessarily required.

The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

1 Lower traveling body 1L Travel hydraulic motor 1R Travel hydraulic motor 2 Swing mechanism 2A Swing hydraulic motor 3 Upper rotating body 4 Boom 5 Arm 6 Bucket 7 Boom cylinder 8 Arm cylinder 9 Bucket cylinder 10 Cabin 11 Engine 13 Regulator 14 Main pump 15 Pilot pump 17 Control valve 19L Negative control pressure sensor 19R Negative control pressure sensor 26 Operation device 28 Discharge pressure sensor 29 Operation pressure sensor 30 Controller 31 Proportional valve 32 Shuttle valve 40 Display device 40L Center bypass oil passage 40R Center bypass oil passage 42 Input device 42L Parallel oil passage 42R Parallel oil passage 43 Voice output device 47 Storage device 50 Machine guidance unit 51 Position calculation unit 52 Distance calculation unit 53 Information transmission unit 54 Automatic control unit 100 Shovel 171 to 176 Control valve 701 Ground 702 Sand pile S1 Boom angle sensor S2, arm angle sensor S3, bucket angle sensor S4, machine body inclination sensor S5, turning state sensor S6, imaging device T1, communication device

Claims (5)

an attachment including a boom, an arm, and a bucket;
A control device for controlling the excavation operation of the attachment;
Equipped with
The control device monitors the condition of soil on the opening side of the bucket during an excavation operation.
Shovel. The control device controls the excavation operation of the attachment taking into account the state of the soil and sand.
The shovel according to claim 1. The state of the soil is the angle of the soil pile with respect to the horizontal plane.
The shovel according to claim 1. The state of the soil is the amount of soil loaded into the bucket.
The shovel according to claim 1. The state of the soil is the height of the soil pile relative to the ground.
The shovel according to claim 1.

Images