JP2024079409A - Control device of shovel, and shovel - Google Patents

Abstract

To improve detection of calculation of a weight of items in a bucket.SOLUTION: A control device of a shovel is configured to input a shape of a bucket provided at a tip of an attachment attached to the shovel, and to calculate a weight of an object in the bucket based on the input shape of the bucket and an output of a detection unit whose detection result changes depending on the weight of the object in the bucket.SELECTED DRAWING: Figure 5

Description

The present invention relates to a control device for a shovel and a shovel.

There is a known technique for measuring the weight of an object being transported by an excavator when the excavator loads the object, such as soil and sand, onto the bed of a dump truck (see, for example, Patent Document 1).

JP 2002-4337 A

For example, in the technology described in Patent Document 1, the weight of an object loaded on a shovel is detected based on the thrust of the boom cylinder. In order to detect the weight of an object loaded using the thrust of the boom cylinder, the position of the center of gravity of the object is required. The position of the center of gravity of the object varies depending on the shape of the bucket in which the object is loaded.

One aspect of the present invention provides a technology that improves the accuracy of detecting the weight of an object being transported by taking into account the shape of the bucket.

The control device for a shovel according to one aspect of the present invention is configured to input the shape of a bucket attached to the tip of an attachment attached to the shovel, and to calculate the weight of an object in the bucket based on the input shape of the bucket and the output of a detection unit whose detection result changes depending on the weight of the object in the bucket.

According to one aspect of the present invention, the accuracy of detecting the weight of an object in a bucket is improved.

FIG. 1 is a side view of a shovel according to an embodiment. FIG. 2 is a diagram illustrating an example of a configuration of a shovel according to an embodiment. FIG. 3 is a diagram illustrating an example of a configuration of a hydraulic system of a shovel according to an embodiment. FIG. 4 is a diagram showing a part of a hydraulic system of a shovel according to an embodiment. FIG. 5 is a diagram illustrating an example of components related to a soil weight detection function of the shovel according to the embodiment. FIG. 6 is a diagram showing an example of the configuration of a main screen displayed on the display device of the shovel according to the embodiment. FIG. 7 is a schematic diagram illustrating parameters related to calculation of the weight of earth and sand loaded in the bucket of the shovel according to the embodiment. FIG. 8 is a schematic diagram illustrating parameters related to calculation of the weight of earth and sand loaded in the bucket of the shovel according to the embodiment. FIG. 9 is a diagram illustrating a concept of the correspondence relationship held in the center of gravity position holding table according to the embodiment. FIG. 10 is a flowchart showing a processing procedure up to determining the weight of the load loaded in the bucket in the controller according to the embodiment.

The following describes an embodiment of the present invention with reference to the drawings. The embodiments described below are illustrative and do not limit the invention, and all features and combinations described in the embodiments are not necessarily essential to the invention. In addition, identical or corresponding components in each drawing are denoted by identical or corresponding reference numerals, and descriptions thereof may be omitted.

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

In FIG. 1, the shovel 100 is positioned on a horizontal plane facing the upward slope ES of the construction target, and an upward slope BS (i.e., the slope shape after construction on the upward slope ES), which is an example of the target construction surface described below, is also shown. Note that the upward slope ES of the construction target is provided with a cylinder (not shown) that indicates the normal direction of the upward slope BS, which is the target construction surface.

The excavator 100 according to this embodiment includes 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 described later). 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 described later) 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 can change the orientation of the upper rotating body 3.

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

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

The bucket 6 is an example of an end attachment, and other end attachments, such as a slope bucket, a dredging bucket, or a breaker, may be attached to the tip of the arm 5 instead of the bucket 6 depending on the type of work being performed.

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 this embodiment will be described with reference to FIG. 2 in addition to FIG.

FIG. 2 is a diagram that illustrates an example of the configuration of the shovel 100 according to this embodiment.
In FIG. 2, the mechanical power system, hydraulic oil lines, pilot lines, and electrical control system are indicated by double lines, solid lines, dashed lines, and dotted lines, respectively.

The drive system of the excavator 100 according to this embodiment 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 according to this embodiment includes hydraulic actuators such as the travel hydraulic motors 1L, 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, 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, as described below.

The control valve 17 is a hydraulic control device that controls the hydraulic system in the excavator 100. In this embodiment, the control valve 17 includes control valves 171 to 176. The control valve 175 includes a control valve 175L and a control valve 175R, and the control valve 176 includes a control valve 176L and a control valve 176R. The control valve 17 is configured to selectively supply hydraulic oil discharged by the main pump 14 to one or more hydraulic actuators through the control valves 171 to 176. The control valves 171 to 176 control, for example, the flow rate of hydraulic oil flowing from the main pump 14 to the hydraulic actuators and the flow rate of hydraulic oil flowing from the hydraulic actuators to the hydraulic oil tank. The hydraulic actuators include a boom cylinder 7, an arm cylinder 8, a bucket cylinder 9, traveling hydraulic motors 1L and 1R, and a swing hydraulic motor 2A. The traveling hydraulic motors 1L and 1R include a left traveling hydraulic motor 1L and a right traveling hydraulic motor 1R. More specifically, control valve 171 corresponds to travel hydraulic motor 1L, control valve 172 corresponds to travel hydraulic motor 1R, and control valve 173 corresponds to swing hydraulic motor 2A. 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. Control valve 175 includes control valves 175L and 175R, for example, as described below, and control valve 176 includes control valves 176L and 176R, for example, as described below. Details of control valves 171 to 176 will be described later.

The pilot pump 15 is an example of a pilot pressure generating device, and is configured to supply hydraulic oil to hydraulic control devices via a pilot line. In this embodiment, the pilot pump 15 is a fixed displacement hydraulic pump. However, the pilot pressure generating device may be realized by the main pump 14. That is, the main pump 14 may have a function of supplying hydraulic oil to various hydraulic control devices via a pilot line, in addition to a function of supplying hydraulic oil to the control valve 17 via a hydraulic oil line. In this case, the pilot pump 15 may be omitted.

The operating device 26 is a device that an operator uses to operate the actuator. The actuator includes at least one of a hydraulic actuator and an electric actuator.

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.

The operation sensor 29 is configured to detect the operation content of the operator using the operating device 26. In this embodiment, the operation sensor 29 detects the operation direction and operation amount of the operating device 26 corresponding to each actuator, and outputs the detected value to the controller 30. In this embodiment, the controller 30 controls the opening area of the proportional valve 31 according to the output of the operation sensor 29. Then, the controller 30 supplies the hydraulic oil discharged by the pilot pump 15 to the pilot port of the corresponding control valve in the control valve 17. The pressure of the hydraulic oil (pilot pressure) supplied to each pilot port is, in principle, a pressure according to the operation direction and operation amount of the operating device 26 corresponding to each hydraulic actuator. In this way, the operating device 26 is configured to be able to supply the hydraulic oil discharged by the pilot pump 15 to the pilot port of the corresponding control valve in the control valve 17.

The proportional valve 31, which functions as a control valve for machine control, is disposed in a pipe connecting the pilot pump 15 and the pilot port of the control valve in the control valve 17, and is configured so that the flow area of the pipe can be changed. In this embodiment, the proportional valve 31 operates in response to a control command output by the controller 30. Therefore, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the pilot port of the control valve in the control valve 17 via the proportional valve 31, regardless of the operation of the operating device 26 by the operator. The proportional valve 31 includes, for example, proportional valves 31AL, 31AR, 31BL, 31BR, 31CL, and 31CR, as described below.

With this configuration, the controller 30 can operate the hydraulic actuator corresponding to a specific operating device 26 even when no operation is being performed on that specific operating device 26.

The control system of the excavator 100 according to this embodiment includes a controller 30, a display device 40, an input device 42, an audio output device 43, a storage device 47, a boom angle sensor S1, an arm angle sensor S2, a bucket angle sensor S3, a machine body inclination sensor S4, a turning state sensor S5, an imaging device S6, a positioning device PS, 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. For example, the controller 30 is configured mainly with a microcomputer including a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), a non-volatile auxiliary storage device, various input/output interfaces, etc. The controller 30 realizes various functions by, for example, executing various programs stored in the ROM or non-volatile auxiliary storage device on the CPU.

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

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

For example, the controller 30 also controls a machine guidance function that guides the operator in manually operating the shovel 100 through the operating device 26. For example, the controller 30 also controls a machine control function that automatically assists the operator in manually operating the shovel 100 through the operating device 26. That is, the controller 30 includes a machine guidance unit 50 as a functional unit related to the machine guidance function and the machine control function. The controller 30 also includes a bucket shape setting unit and a soil weight processing unit 60, which will be described later.

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 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 26R, 26L, 26DR, and 26DL, button switches, levers, toggles, rotary dials, etc., 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, "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, "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 tilt sensor S4 detects the tilt state of the machine body (upper rotating body 3 or lower running body 1) relative to the horizontal plane. The machine body tilt sensor S4 is attached, for example, to the upper rotating body 3, and detects the tilt angles around two axes in the forward/backward and left/right directions (hereinafter, "forward/rearward tilt angle" and "left/right tilt angle") of the shovel 100 (i.e., upper rotating body 3). The machine body tilt 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 tilt angle (forward/backward tilt angle and left/right tilt angle) by the machine body tilt 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, which serves as a spatial recognition device, captures images of the periphery of the shovel 100. The imaging device S6 includes a camera S6F that captures an image in front of the shovel 100, a camera S6L that captures an image to the left of the shovel 100, a camera S6R that captures an image to the right of the shovel 100, and a camera S6B that captures an image to the rear of the shovel 100. The imaging device S6 may include an attachment camera attached to an attachment.

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 device 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 as a spatial recognition device may function as an object detection device. In this case, the imaging device S6 may detect an object present around the shovel 100. The object to be detected may include, for example, a person, an animal, a vehicle, a construction machine, a building, or a hole. 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 or a distance image sensor. The spatial recognition device is, for example, a monocular camera having an imaging element such as a CCD or CMOS, and outputs the captured image to the display device 40. The spatial recognition device may also be configured to calculate the distance from the spatial recognition device or the shovel 100 to the recognized object. In addition to the imaging device S6, other object detection devices such as an ultrasonic sensor, a millimeter wave radar, a LIDAR, or an infrared sensor may be provided as the spatial recognition device. When a millimeter wave radar, ultrasonic sensor, laser radar, or the like is used as the spatial recognition device, multiple signals (laser light, etc.) may be emitted to an object, and the reflected signals may be received to detect the distance and direction of the object from the reflected signals. When an object detection device is provided, the imaging device S6 may be omitted.

If a person is detected by the spatial recognition device within a predetermined distance from the shovel 100 before the actuator operates, the controller 30 may put the actuator in an inoperable state or in a slow-speed state so that the shovel 100 does not move excessively even if the operator operates the control device 26. Specifically, if a person is detected within a predetermined distance from the shovel 100, the controller 30 can put the actuator in an inoperable state by locking the gate lock valve. In the case of an electric control device 26, the controller 30 can put the actuator in an inoperable state by invalidating the signal sent from the controller 30 to the control valve for operation (proportional valve 31). The same applies when using another type of control device 26 (for example, when using an operation control valve that outputs a pilot pressure corresponding to a control command from the controller 30 and applies the pilot pressure to the pilot port of the corresponding control valve in the control valve 17). When it is desired to put the actuator in a slow-speed state, the controller 30 can put the actuator in a slow-speed state by reducing the output of the signal (for example, a current signal) sent from the controller 30 to the control valve for operation. In this way, when an object is detected within a predetermined distance range, the actuator is not driven even if the operating device 26 is operated, or the actuator is driven at a slow speed with an output smaller than the output of the signal when no object is detected within the predetermined distance range. Furthermore, when a person is detected within a predetermined distance range from the shovel while the operator is operating the operating device 26, the controller 30 may stop or decelerate the actuator regardless of the operation content of the operator. Specifically, when a person is detected within a predetermined distance range from the shovel 100, the controller 30 stops the actuator by locking the gate lock valve. In the case of using an operating control valve that outputs a pilot pressure corresponding to a control command from the controller 30 and applies the pilot pressure to the pilot port of the corresponding control valve in the control valve 17, the controller 30 can disable the actuator or decelerate the actuator by invalidating the signal transmitted from the controller 30 to the operating control valve or by outputting a deceleration command. Furthermore, when the detected object is a dump truck, the stop control may be omitted. In this case, the actuator may be controlled to avoid the detected dump truck. In this way, the actuator may be controlled based on the type of the detected object.

The imaging device S6 may be directly connected to the controller 30 so as to be able to communicate with it. The spatial recognition device may also be disposed outside the shovel 100. In this case, the controller 30 may acquire information output by the spatial recognition device via the communication device T1. Specifically, the spatial recognition device may be attached to a multicopter for aerial photography, a steel tower installed at a work site, a dump truck DT, or the like. The controller 30 may then determine the state of the spilling soil and sand based on an image seen from any position around the shovel 100.

A boom rod pressure sensor S7R and a boom bottom pressure sensor S7B are attached to the boom cylinder 7. An arm rod pressure sensor S8R and an arm bottom pressure sensor S8B are attached to the arm cylinder 8. A bucket rod pressure sensor S9R and a bucket bottom pressure sensor S9B are attached to the bucket cylinder 9. The boom rod pressure sensor S7R, the boom bottom pressure sensor S7B, the arm rod pressure sensor S8R, the arm bottom pressure sensor S8B, the bucket rod pressure sensor S9R and the bucket bottom pressure sensor S9B are collectively referred to as the "cylinder pressure sensors."

The boom rod pressure sensor S7R detects the pressure in the rod side oil chamber of the boom cylinder 7 (hereinafter referred to as the "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 the "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 the "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 the "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 the "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 the "bucket bottom pressure").

The positioning device PS measures the position and orientation of the upper rotating body 3. The positioning device PS 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 the positioning device PS to detect the orientation of the upper rotating body 3 may be substituted 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 determine 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. Furthermore, if a breaker, for example, 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 target construction surface and the tip position of the bucket 6 coincide with each other.

The machine guidance unit 50 acquires information from the boom angle sensor S1, arm angle sensor S2, bucket angle sensor S3, vehicle tilt sensor S4, turning state sensor S5, imaging device S6, positioning device PS, 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, an automatic control unit 54, a turning angle calculation unit 55, and a relative angle calculation unit 56 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 valve 173, the control valves 175L, 175R, and the control valve 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, "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, "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 a 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 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.

When an MC switch or the like is pressed, the automatic control unit 54 may automatically rotate the rotation hydraulic motor 2A (an example of an actuator) to make the upper rotating body 3 face the target construction surface. Hereinafter, the control by the controller 30 (automatic control unit 54) to face the upper rotating body 3 face the target construction surface is referred to as "facing control." This allows an operator or the like to face the upper rotating body 3 face the target construction surface simply by pressing a specified switch, or, with the switch pressed, by operating a lever device 26C (described below) corresponding to a turning operation. Also, an operator can face the upper rotating body 3 face the target construction surface and start the machine control function related to the excavation work of the target construction surface, etc., described above, simply by pressing the MC switch.

For example, when the upper rotating body 3 of the shovel 100 faces the target construction surface, the tip of the attachment (e.g., the tip or back of the bucket 6 as the working part) can be moved along the inclination direction of the target construction surface (upward slope BS) in accordance with the operation of the attachment. Specifically, when the upper rotating body 3 of the shovel 100 faces the target construction surface, the working surface of the attachment (attachment working surface) perpendicular to the rotation plane of the shovel 100 includes the normal to the target construction surface corresponding to the cylinder (in other words, it is along the normal).

If the working surface of the attachment of the shovel 100 does not include the normal of the target construction surface corresponding to the cylinder, the tip of the attachment cannot move the target construction surface in the inclined direction. As a result, the shovel 100 cannot properly construct the target construction surface. In response to this, the automatic control unit 54 can automatically rotate the turning hydraulic motor 2A to orient the upper turning body 3 in the correct position. This allows the shovel 100 to properly construct the target construction surface.

In the facing control, the automatic control unit 54 determines that the shovel is facing the target construction surface, for example, when the left end vertical distance between the coordinate point of the left end of the tip of the bucket 6 and the target construction surface (hereinafter simply referred to as the "left end vertical distance") and the right end vertical distance between the coordinate point of the right end of the tip of the bucket 6 and the target construction surface (hereinafter simply referred to as the "right end vertical distance") are equal. In addition, the automatic control unit 54 may determine that the shovel 100 is facing the target construction surface not when the left end vertical distance and the right end vertical distance are equal (i.e., when the difference between the left end vertical distance and the right end vertical distance becomes zero), but when the difference becomes equal to or less than a predetermined value.

In addition, the automatic control unit 54 may operate the swing hydraulic motor 2A in the facing control, for example, based on the difference between the left end vertical distance and the right end vertical distance. Specifically, when the lever device 26C corresponding to the swing operation is operated with a predetermined switch such as an MC switch pressed, the automatic control unit 54 judges whether the lever device 26C is operated in a direction to face the upper swing body 3 to the target construction surface. For example, when the lever device 26C is operated in a direction to increase the vertical distance between the tip of the bucket 6 and the target construction surface (upward slope BS), the automatic control unit 54 does not execute the facing control. On the other hand, when the swing operation lever is operated in a direction to decrease the vertical distance between the tip of the bucket 6 and the target construction surface (upward slope BS), the automatic control unit 54 executes the facing control. As a result, the automatic control unit 54 can operate the swing hydraulic motor 2A so that the difference between the left end vertical distance and the right end vertical distance becomes smaller. After that, when the difference becomes equal to or less than a predetermined value or becomes zero, the automatic control unit 54 stops the swing hydraulic motor 2A. The automatic control unit 54 may also set a rotation angle at which the difference is equal to or less than a predetermined value or zero as a target angle, and control the operation of the rotation hydraulic motor 2A so that the angle difference between the target angle and the current rotation angle (specifically, the detection value based on the detection signal of the rotation state sensor S5) becomes zero. In this case, the rotation angle is, for example, the angle of the front and rear axes of the upper rotating body 3 relative to the reference direction.

As described above, when a turning electric motor is installed on the excavator 100 instead of the turning hydraulic motor 2A, the automatic control unit 54 performs facing control with the turning electric motor (an example of an actuator) as the control target.

The slewing angle calculation unit 55 calculates the slewing angle of the upper rotating body 3. This allows the controller 30 to identify the current orientation of the upper rotating body 3. The slewing angle calculation unit 55 calculates the angle of the front-rear axis of the upper rotating body 3 relative to a reference direction as the slewing angle, for example, based on the output signal of the GNSS compass included in the positioning device PS. The slewing angle calculation unit 55 may also calculate the slewing angle based on the detection signal of the slewing state sensor S5. Furthermore, if a reference point is set at the construction site, the slewing angle calculation unit 55 may use the direction of the reference point as viewed from the slewing axis as the reference direction.

The rotation angle indicates the direction in which the attachment working surface extends relative to the reference direction. The attachment working surface is, for example, a virtual plane that cuts the attachment longitudinally and is positioned so as to be perpendicular to the rotation plane. The rotation plane is, for example, a virtual plane that includes the bottom surface of the rotating frame that is perpendicular to the rotation axis. The controller 30 (machine guidance unit 50) determines that the upper rotating body 3 is directly facing the target construction surface when it determines, for example, that the attachment working surface includes the normal to the target construction surface.

The relative angle calculation unit 56 calculates the rotation angle (relative angle) required to make the upper rotating body 3 face the target construction surface. The relative angle is, for example, the relative angle formed between the direction of the front-rear axis of the upper rotating body 3 when the upper rotating body 3 is faced directly to the target construction surface and the current direction of the front-rear axis of the upper rotating body 3. The relative angle calculation unit 56 calculates the relative angle based on, for example, data related to the target construction surface stored in the storage device 47 and the rotation angle calculated by the rotation angle calculation unit 55.

When the lever device 26C corresponding to the rotation operation is operated with a predetermined switch such as an MC switch pressed, the automatic control unit 54 determines whether the upper rotating body 3 has been rotated in a direction to face the target construction surface. If the automatic control unit 54 determines that the upper rotating body 3 has been rotated in a direction to face the target construction surface, it sets the relative angle calculated by the relative angle calculation unit 56 as the target angle. Then, if the change in the rotation angle after the lever device 26C is operated reaches the target angle, the automatic control unit 54 may determine that the upper rotating body 3 faces the target construction surface and stop the movement of the rotation hydraulic motor 2A. As a result, the automatic control unit 54 can make the upper rotating body 3 face the target construction surface, assuming the configuration shown in FIG. 2. In the above embodiment of the facing control, an example of the facing control to the target construction surface is shown, but this is not limited to this. For example, even in the scooping operation when loading temporary soil and sand onto a dump truck, a target trajectory (target excavation trajectory) corresponding to the target volume may be generated, and the turning operation may be controlled so that the attachment faces the target excavation trajectory. In this case, the target excavation trajectory is changed each time a scooping operation is performed. Therefore, after the soil is discharged onto the dump truck, the attachment is controlled to face the newly changed target excavation trajectory.

[Excavator hydraulic system]
Next, the hydraulic system of the excavator 100 according to this embodiment will be described with reference to FIG.

Figure 3 is a diagram showing an example of the configuration of a hydraulic system of a shovel 100 according to this embodiment. In Figure 3, the mechanical power system, hydraulic oil lines, pilot lines, and electrical control system are shown by double lines, solid lines, dashed lines, and dotted lines, respectively, as in Figure 2 and other figures.

The hydraulic system realized by this hydraulic circuit circulates hydraulic oil from each of the main pumps 14L, 14R driven by the engine 11 through the center bypass oil passages C1L, C1R and the parallel oil passages C2L, C2R to the hydraulic oil tank.

The center bypass oil passage C1L starts at the main pump 14L, passes through the control valves 171, 173, 175L, and 176L arranged in the control valve 17, and reaches the hydraulic oil tank.

The center bypass oil passage C1R 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, 176R supply hydraulic oil discharged by the main pumps 14L, 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 each adjust the flow rate of hydraulic oil supplied to or discharged from the hydraulic actuator and switch the flow direction according to the pilot pressure acting on the pilot port.

The parallel oil passage C2L 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 C1L. Specifically, the parallel oil passage C2L branches off from the center bypass oil passage C1L 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 176R. This allows the parallel oil passage C2L to supply hydraulic oil to a more downstream control valve when the flow of hydraulic oil through the center bypass oil passage C1L is restricted or blocked by any of the control valves 171, 173, and 175L.

The parallel oil passage C2R 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 C1R. Specifically, the parallel oil passage C2R branches off from the center bypass oil passage C1R 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. The parallel oil passage C2R can supply hydraulic oil to a more downstream control valve when the flow of hydraulic oil through the center bypass oil passage C1R 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, respectively, 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, 13R according to the discharge pressures of the main pumps 14L, 14R.

Negative control throttles (hereinafter "negative control throttles") 18L, 18R are provided in the center bypass oil passages C1L, C1R 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 (hereinafter "negative control pressure") for controlling the regulators 13L, 13R.

The 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 the 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 (state shown in FIG. 3) 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 C1L, C1R to reach 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 the pressure loss (pumping loss) that occurs when the discharged hydraulic oil passes through the center bypass oil passages C1L, C1R.

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.

The operating device 26 includes a left operating lever 26L, a right operating lever 26R, and a driving lever 26D. The driving lever 26D includes a left driving lever 26DL and a right driving lever 26DR.

The left operating lever 26L is used for rotation operation and operation of the arm 5. When the left operating lever 26L is operated in the forward/backward direction, the hydraulic oil discharged by the pilot pump 15 is used to introduce a control pressure according to the amount of lever operation into the pilot port of the control valve 176. When the left operating lever 26L is operated in the left/right direction, the hydraulic oil discharged by the pilot pump 15 is used to introduce a control pressure according to the amount of lever operation into the pilot port of the control valve 173.

Specifically, when the left operating lever 26L is operated in the arm closing direction, it introduces hydraulic oil to the right pilot port of the control valve 176L and introduces hydraulic oil to the left pilot port of the control valve 176R. When the left operating lever 26L is operated in the arm opening direction, it introduces hydraulic oil to the left pilot port of the control valve 176L and introduces hydraulic oil to the right pilot port of the control valve 176R. When the left operating lever 26L is operated in the left turning direction, it introduces hydraulic oil to the left pilot port of the control valve 173, and when operated in the right turning direction, it introduces hydraulic oil to the right pilot port of the control valve 173.

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 oil discharged by the pilot pump 15 to introduce a control pressure according to the amount of lever operation into the pilot port of the control valve 175. When the right operating lever 26R is operated in the left/right direction, it uses the hydraulic oil discharged by the pilot pump 15 to introduce a control pressure according to the amount of lever operation into the pilot port of the control valve 174.

Specifically, when the right operating lever 26R is operated in the boom lowering direction, it introduces hydraulic oil to 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 oil to the right pilot port of the control valve 175L and also introduces hydraulic oil to the left pilot port of the control valve 175R. When the right operating lever 26R is operated in the bucket closing direction, it introduces hydraulic oil to the right pilot port of the control valve 174, and when the right operating lever 26R is operated in the bucket opening direction, it introduces hydraulic oil to the left pilot port of the control valve 174.

In the following, the left operating lever 26L operated in the left-right direction may be referred to as the "swing operating lever," and the left operating lever 26L operated in the front-rear direction may be referred to as the "arm operating lever." In addition, the right operating lever 26R operated in the left-right direction may be referred to as the "bucket operating lever," and the right operating lever 26R operated in the front-rear direction may be referred to as the "boom operating lever."

The left travel lever 26DL is used to operate the left crawler 1CL. It may be configured to be linked to the left travel pedal. When the left travel lever 26DL is operated in the forward/backward direction, it uses the hydraulic oil 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 1CR. It may be configured to be linked to the right travel pedal. When the right travel lever 26DR is operated in the forward/backward direction, it uses the hydraulic oil 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.

The operation sensor 29 is configured to detect the operation of the operation device 26 by the operator. In this embodiment, the operation sensor 29 detects the operation direction and operation amount of the operation device 26 corresponding to each actuator, and outputs the detected value to the controller 30.

The operation sensor 29 includes operation sensors 29LA, 29LB, 29RA, 29RB, 29DL, and 29DR. The operation sensor 29LA detects the content of the operation of the left operating lever 26L in the forward/rearward direction by the operator, and outputs the detected value to the controller 30. The content of the operation includes, for example, the lever operation direction, the lever operation amount (lever operation angle), etc.

Similarly, the operation sensor 29LB detects the operation of the left operating lever 26L in the left-right direction by the operator, and outputs the detected value to the controller 30. The operation sensor 29RA detects the operation of the right operating lever 26R in the forward-backward direction by the operator, and outputs the detected value to the controller 30. The operation sensor 29RB detects the operation of the right operating lever 26R in the left-right direction by the operator, and outputs the detected value to the controller 30. The operation sensor 29DL detects the operation of the left travel lever 26DL in the forward-backward direction by the operator, and outputs the detected value to the controller 30. The operation sensor 29DR detects the operation of the right travel lever 26DR in the forward-backward direction by the operator, and outputs the detected value to the controller 30.

The controller 30 receives the output of the operation sensor 29, and outputs a control command to the regulator 13 as necessary, thereby changing the discharge volume of the main pump 14. The controller 30 also receives the output of the control pressure sensor 19 provided upstream of the orifice 18, and outputs a control command to the regulator 13 as necessary, thereby changing the discharge volume of the main pump 14. The orifice 18 includes a left orifice 18L and a right orifice 18R, and the control pressure sensor 19 includes negative control pressure sensors 19L and 19R.

[Configuration details for excavator machine control function]
Next, with reference to FIG. 4 in addition to FIG. 3, a detailed configuration regarding the machine control function of the shovel 100 will be described.

Figure 4 shows a portion of the hydraulic system. Specifically, Figure 4(A) shows the hydraulic system portion related to the operation of the arm cylinder 8, and Figure 4(B) shows the hydraulic system portion related to the operation of the boom cylinder 7. Figure 4(C) shows the hydraulic system portion related to the operation of the bucket cylinder 9, and Figure 4(D) shows the hydraulic system portion related to the operation of the swing hydraulic motor 2A.

As shown in FIG. 4, the hydraulic system includes a proportional valve 31. The proportional valve 31 includes proportional valves 31AL to 31DL and 31AR to 31DR.

The proportional valve 31 functions as a control valve for machine control. The proportional valve 31 is disposed in a pipe connecting the pilot pump 15 and the pilot port of the corresponding control valve in the control valve 17, and is configured to be able to change the flow area of the pipe. In this embodiment, the proportional valve 31 operates in response to a control command output by the controller 30. Therefore, the controller 30 can supply the hydraulic oil discharged by the pilot pump 15 to the pilot port of the corresponding control valve in the control valve 17 via the proportional valve 31, regardless of the operation of the operating device 26 by the operator. Then, the controller 30 can apply the pilot pressure generated by the proportional valve 31 to the pilot port of the corresponding control valve.

With this configuration, the controller 30 can 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, the controller 30 can forcibly stop the operation of the hydraulic actuator corresponding to that specific operating device 26 even when an operation is being performed on that specific operating device 26.

For example, as shown in FIG. 4(A), the left operating lever 26L is used to operate the arm 5. Specifically, the left operating lever 26L uses hydraulic oil discharged by the pilot pump 15 to apply pilot pressure corresponding to the operation in the forward and backward directions to the pilot port of the control valve 176. More specifically, when the left operating lever 26L is operated in the arm closing direction (rearward), it applies pilot pressure corresponding to the operation amount to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R. Also, when the left operating lever 26L is operated in the arm opening direction (forward), it applies pilot pressure corresponding to the operation amount to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R.

The operation device 26 is provided with a switch SW. In this embodiment, the switch SW includes a switch SW1 and a switch SW2. The switch SW1 is a push button switch provided at the tip of the left operation lever 26L. The operator can operate the left operation lever 26L while pressing the switch SW1. The switch SW1 may be provided on the right operation lever 26R or at another position in the cabin 10. The switch SW2 is a push button switch provided at the tip of the left travel lever 26DL. The operator can operate the left travel lever 26DL while pressing the switch SW2. The switch SW2 may be provided on the right travel lever 26DR or at another position in the cabin 10.

The operation sensor 29LA detects the forward/rearward operation of the left operating lever 26L by the operator and outputs the detected value to the controller 30.

The proportional valve 31AL operates in response to a control command (current command) output by the controller 30. The proportional valve 31AL adjusts the pilot pressure by hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the proportional valve 31AL. The proportional valve 31AR operates in response to a control command (current command) output by the controller 30. The proportional valve 31AR adjusts the pilot pressure by hydraulic oil introduced from the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the proportional valve 31AR. The proportional valve 31AL can adjust the pilot pressure so that the control valve 176L and the control valve 176R can be stopped at any valve position. Similarly, the proportional valve 31AR can adjust the pilot pressure so that the control valve 176L and the control valve 176R can be stopped at any valve position.

With this configuration, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the proportional valve 31AL in response to the arm closing operation by the operator. Furthermore, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 176L and the left pilot port of the control valve 176R via the proportional valve 31AL, regardless of the arm closing operation by the operator. In other words, the controller 30 can close the arm 5 in response to the arm closing operation by the operator or regardless of the arm closing operation by the operator.

In addition, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the proportional valve 31AR in response to the arm opening operation by the operator. In addition, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 176L and the right pilot port of the control valve 176R via the proportional valve 31AR, regardless of the arm opening operation by the operator. In other words, the controller 30 can open the arm 5 in response to the arm opening operation by the operator or regardless of the arm opening operation by the operator.

In addition, with this configuration, even if the operator is performing an arm closing operation, the controller 30 can, if necessary, reduce the pilot pressure acting on the pilot ports on the closing side of the control valve 176 (the left pilot port of the control valve 176L and the right pilot port of the control valve 176R) to forcibly stop the closing operation of the arm 5. The same applies to the case where the opening operation of the arm 5 is forcibly stopped when the operator is performing an arm opening operation.

Even if the operator is performing an arm closing operation, the controller 30 may, if necessary, control the proportional valve 31AR to increase the pilot pressure acting on the opening pilot port of the control valve 176 (the right pilot port of the control valve 176L and the left pilot port of the control valve 176R) opposite the closing pilot port of the control valve 176, and forcibly return the control valve 176 to the neutral position, thereby forcibly stopping the closing operation of the arm 5. The same applies to the case where the opening operation of the arm 5 is forcibly stopped when the operator is performing an arm opening operation.

Although the explanation with reference to the following Figures 4(B) to 4(D) is omitted, the same applies to the case where the operation of the boom 4 is forcibly stopped when the operator is performing a boom-raising or boom-lowering operation, the case where the operation of the bucket 6 is forcibly stopped when the operator is performing a bucket-closing or bucket-opening operation, and the case where the rotation operation of the upper rotating body 3 is forcibly stopped when the operator is performing a rotation operation.

The same applies when the traveling operation of the lower traveling body 1 is forcibly stopped while the operator is operating the vehicle.

As shown in FIG. 4(B), the right operating lever 26R is used to operate the boom 4. Specifically, the right operating lever 26R uses hydraulic oil discharged by the pilot pump 15 to apply pilot pressure corresponding to operation in the forward and backward directions to the pilot port of the control valve 175. More specifically, when the right operating lever 26R is operated in the boom-up direction (rearward), it applies pilot pressure corresponding to the operation amount to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R. When the right operating lever 26R is operated in the boom-down direction (forward), it applies pilot pressure corresponding to the operation amount to the right pilot port of the control valve 175R.

The operation sensor 29RA detects the forward/rearward operation of the right operating lever 26R by the operator and outputs the detected value to the controller 30.

The proportional valve 31BL operates in response to a control command (current command) output by the controller 30. The proportional valve 31BL adjusts the pilot pressure by hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 175L and the left pilot port of the control valve 175R via the proportional valve 31BL. The proportional valve 31BR operates in response to a control command (current command) output by the controller 30. The proportional valve 31BR adjusts the pilot pressure by hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 175R via the proportional valve 31BR. The proportional valve 31BL can adjust the pilot pressure so that the control valves 175L and 175R can be stopped at any valve position. The proportional valve 31BR can adjust the pilot pressure so that the control valve 175R can be stopped at any valve position.

With this configuration, the controller 30 can supply hydraulic oil discharged by 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 31BL in response to the boom-raising operation by the operator. Furthermore, the controller 30 can supply hydraulic oil discharged by 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 31BL, regardless of the boom-raising operation by the operator. In other words, the controller 30 can raise the boom 4 in response to the boom-raising operation by the operator or regardless of the boom-raising operation by the operator.

In addition, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 175R via the proportional valve 31BR in response to the boom lowering operation by the operator. In addition, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 175R via the proportional valve 31BR, regardless of the boom lowering operation by the operator. In other words, the controller 30 can lower the boom 4 in response to the boom lowering operation by the operator or regardless of the boom lowering operation by the operator.

As shown in FIG. 4(C), the right operating lever 26R is also used to operate the bucket 6. Specifically, the right operating lever 26R uses hydraulic oil discharged by the pilot pump 15 to apply pilot pressure corresponding to left/right operation to the pilot port of the control valve 174. More specifically, when the right operating lever 26R is operated in the bucket closing direction (leftward), it applies pilot pressure corresponding to the amount of operation to the left pilot port of the control valve 174. Also, when the right operating lever 26R is operated in the bucket opening direction (rightward), it applies pilot pressure corresponding to the amount of operation to the right pilot port of the control valve 174.

The operation sensor 29RB detects the left/right operation of the right operating lever 26R by the operator and outputs the detected value to the controller 30.

The proportional valve 31CL operates in response to a control command (current command) output by the controller 30. It adjusts the pilot pressure by the hydraulic oil introduced from the pilot pump 15 to the left pilot port of the control valve 174 via the proportional valve 31CL. The proportional valve 31CR operates in response to a control command (current command) output by the controller 30. It adjusts the pilot pressure by the hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 174 via the proportional valve 31CR. The proportional valve 31CL can adjust the pilot pressure so that the control valve 174 can be stopped at any valve position. Similarly, the proportional valve 31CR can adjust the pilot pressure so that the control valve 174 can be stopped at any valve position.

With this configuration, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 174 via the proportional valve 31CL in response to the bucket closing operation by the operator. The controller 30 can also supply hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 174 via the proportional valve 31CL, regardless of the bucket closing operation by the operator. In other words, the controller 30 can close the bucket 6 in response to the bucket closing operation by the operator or regardless of the bucket closing operation by the operator.

In addition, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 174 via the proportional valve 31CR in response to the bucket opening operation by the operator. In addition, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 174 via the proportional valve 31CR, regardless of the bucket opening operation by the operator. In other words, the controller 30 can open the bucket 6 in response to the bucket opening operation by the operator or regardless of the bucket opening operation by the operator.

As shown in FIG. 4(D), the left operating lever 26L is also used to operate the turning mechanism 2. Specifically, the left operating lever 26L uses hydraulic oil discharged by the pilot pump 15 to apply pilot pressure corresponding to operation in the left and right directions to the pilot port of the control valve 173. More specifically, when the left operating lever 26L is operated in the left turning direction (left direction), it applies pilot pressure corresponding to the amount of operation to the left pilot port of the control valve 173. Also, when the left operating lever 26L is operated in the right turning direction (right direction), it applies pilot pressure corresponding to the amount of operation to the right pilot port of the control valve 173.

The operation sensor 29LB detects the left/right operation of the left operating lever 26L by the operator and outputs the detected value to the controller 30.

The proportional valve 31DL operates in response to a control command (current command) output by the controller 30. It adjusts the pilot pressure by the hydraulic oil introduced from the pilot pump 15 to the left pilot port of the control valve 173 via the proportional valve 31DL. The proportional valve 31DR operates in response to a control command (current command) output by the controller 30. It adjusts the pilot pressure by the hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 173 via the proportional valve 31DR. The proportional valve 31DL can adjust the pilot pressure so that the control valve 173 can be stopped at any valve position. Similarly, the proportional valve 31DR can adjust the pilot pressure so that the control valve 173 can be stopped at any valve position.

With this configuration, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 173 via the proportional valve 31DL in response to a left rotation operation by the operator. The controller 30 can also supply hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 173 via the proportional valve 31DL, regardless of a left rotation operation by the operator. In other words, the controller 30 can rotate the rotation mechanism 2 to the left in response to a left rotation operation by the operator or regardless of a left rotation operation by the operator.

In addition, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 173 via the proportional valve 31DR in response to a right turning operation by the operator. In addition, the controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 173 via the proportional valve 31DR, regardless of a right turning operation by the operator. In other words, the controller 30 can rotate the turning mechanism 2 to the right in response to a right turning operation by the operator or regardless of a right turning operation by the operator.

The left travel lever 26DL shown in FIG. 3 is used to operate the left crawler 1CL. Specifically, the left travel lever 26DL uses hydraulic oil discharged by the pilot pump 15 to apply pilot pressure corresponding to forward and backward operation to the pilot port of the control valve 171. The operation sensor 29DL electrically detects the content of the forward and backward operation of the left travel lever 26DL by the operator, and outputs a current command indicating the detected value to the controller 30. This causes the controller 30 to operate according to the current command.

The controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 171 via a proportional valve (not shown) in the same manner as in the configuration described above. In other words, the left crawler 1CL can be moved forward. The controller 30 can also supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 171 via a proportional valve (not shown). In other words, the left crawler 1CL can be moved backward.

The right travel lever 26DR shown in FIG. 3 is used to operate the right crawler 1CR. Specifically, the right travel lever 26DR uses hydraulic oil discharged by the pilot pump 15 to apply pilot pressure corresponding to forward and backward operation to the pilot port of the control valve 172. The operation sensor 29DR electrically detects the content of the forward and backward operation of the right travel lever 26DR by the operator, and outputs a current command indicating the detected value to the controller 30. This causes the controller 30 to operate according to the current command.

The controller 30 can supply hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 172 via a proportional valve (not shown) in the same manner as in the configuration described above. In other words, the right crawler 1CR can be moved forward. The controller 30 can also supply hydraulic oil discharged by the pilot pump 15 to the left pilot port of the control valve 172 via a proportional valve (not shown). In other words, the right crawler 1CR can be moved backward.

The excavator 100 may also be configured to automatically operate the bucket tilt mechanism. In this case, the hydraulic system portion related to the bucket tilt cylinder that constitutes the bucket tilt mechanism may be configured in the same manner as the hydraulic system portion related to the operation of the boom cylinder 7, etc.

Although the description has been given of an electric control lever as the form of the operating device 26, a hydraulic operating lever may be used instead of an electric operating lever. In this case, the lever operation amount of the hydraulic operating lever may be detected in the form of pressure by a pressure sensor and input to the controller 30. In addition, a solenoid valve may be disposed between the operating device 26 as a hydraulic operating lever and the pilot port of each control valve. The solenoid valve is configured to operate in response to an electric signal from the controller 30. With this configuration, when manual operation is performed using the operating device 26 as a hydraulic operating lever, the operating device 26 can move each control valve by increasing or decreasing the pilot pressure in response to the lever operation amount. In addition, each control valve may be configured as an electromagnetic spool valve. In this case, the electromagnetic spool valve operates in response to an electric signal from the controller 30 corresponding to the lever operation amount of the electric operating lever.

[Configuration details for excavator soil weight detection function]
Next, a detailed configuration of the soil weight detection function of the shovel 100 according to this embodiment will be described with reference to Fig. 5. Fig. 5 is a diagram illustrating an example of a configuration part of the shovel 100 according to this embodiment that is related to the soil weight detection function.

The controller 30 according to this embodiment calculates the weight of the soil excavated by the bucket 6 based on the thrust of the boom cylinder 7. When detecting the weight of the soil based on the thrust of the boom cylinder 7, the position of the center of gravity of the soil (hereinafter referred to as the soil center of gravity) is required. The position of the soil center of gravity differs depending on the shape of the bucket 6. Therefore, the controller 30 according to this embodiment includes a bucket shape setting unit 70 as a functional unit related to setting the shape of the bucket 6.

The bucket shape setting unit 70 sets the shape of the bucket 6 attached to the excavator 100. Information indicating the set shape of the bucket 6 is stored, for example, in the storage device 47. Therefore, the shape is set each time the bucket 6 is attached.

The bucket shape setting unit 70 according to this embodiment may perform settings according to information specifying the shape of the bucket 6, which is input from the input device 42 (an example of an operating device). Furthermore, input of the shape of the bucket 6 when setting is not limited to the input device 42. The bucket shape setting unit 70 may perform settings according to information specifying the shape of the bucket 6, which is received from an external device via the communication device T1. The information specifying the shape of the bucket may be any information, and may be, for example, the model number or name of the bucket 6.

Furthermore, the bucket shape setting unit 70 may set the shape of the bucket 6 based on the input captured image information. The captured image information is assumed to show the bucket 6 attached to the shovel 100. The bucket shape setting unit 70 then identifies the shape of the bucket 6 shown in the captured image information, and sets the identified shape of the bucket 6.

Furthermore, when the bucket 6 is replaced, the bucket shape setting unit 70 sets the shape of the bucket 6 as well as the center of gravity and weight of the bucket 6. The center of gravity and weight of the bucket 6 may be associated with the model number or name of the bucket 6 and stored in advance in the storage device 47, or may be input from the input device 42, etc.

The controller 30 includes a soil weight processing unit 60 as a functional unit related to the function of detecting the weight of the soil excavated by the bucket 6 (hereinafter referred to as soil weight).

In this embodiment, the soil weight processing unit 60 recognizes the shape of the bucket 6, and therefore can determine the position of the soil's center of gravity (hereinafter referred to as the soil center of gravity) taking into account the shape of the bucket 6, and then calculate the soil weight taking into account the position of the soil center of gravity. The center of gravity of the soil (an example of a load) loaded in the bucket 6 is designated as Gs. The weight of the soil (an example of a load) loaded in the bucket 6 is designated as Ws.

The position of the soil gravity center Gs changes not only depending on the shape of the bucket 6 but also on the amount of soil excavated by the bucket 6, in other words, the soil weight Ws. In other words, when the soil weight Ws increases or decreases, the position of the soil gravity center Gs changes depending on the shape of the bucket 6 in which the soil is loaded.

For example, in a wide bucket with a flat bottom, the position of the center of gravity of the soil in the front-to-back direction does not change much depending on the weight of the soil Ws, whereas in a bucket with roughly triangular sides that taper from the top to the bottom, the position of the center of gravity Gs of the soil may change in the front-to-back direction depending on the weight of the soil Ws.

The storage device 47 according to this embodiment therefore stores a center of gravity position holding table 47A that associates the soil weight Ws with positional relationship information of the soil center of gravity Gs for each shape of the bucket 6 (type of bucket 6) that can be connected to the shovel 100. The positional relationship information of the soil center of gravity Gs is information related to the position of the soil center of gravity Gs in order to identify the position of the soil center of gravity Gs. Specific positional relationship information of the soil center of gravity Gs will be described later.

The soil weight processing unit 60 then refers to the center of gravity position holding table 47A when calculating the position of the soil gravity center Gs.

For example, the soil weight processing unit 60 calculates the soil weight Ws excavated by the bucket 6 based on the thrust of the boom cylinder 7 and the preset position of the soil center of gravity Gs. The soil weight processing unit 60 then refers to the center of gravity position holding table 47A and calculates the position of the soil center of gravity Gs from the positional relationship information of the soil center of gravity Gs corresponding to the calculated soil weight Ws. The soil weight processing unit 60 then calculates the soil weight Ws excavated by the bucket 6 based on the calculated position of the soil center of gravity Gs and the thrust of the boom cylinder 7.

The soil weight processing unit 60 according to this embodiment alternately and repeatedly calculates the position of the soil center of gravity Gs based on the calculated soil weight Ws, and calculates the soil weight Ws based on the calculated position of the soil center of gravity Gs and the detection results of the thrust of the boom cylinder 7 (by the boom rod pressure sensor S7R or the boom bottom pressure sensor S7B) according to a cycle (e.g., in 0.1 second units) that the controller 30 can execute. By repeatedly performing this process between the completion of the excavation operation and the start of the soil discharge operation, the calculation accuracy of the position of the soil center of gravity Gs improves, and therefore the calculation accuracy of the soil weight Ws can be improved. The specific repetition of the process will be described later.

Next, the specific soil weight processing unit 60 will be described. The soil weight processing unit 60 has a weight calculation unit 61, a maximum load detection unit 62, a load calculation unit 63, a remaining load calculation unit 64, and a center of gravity calculation unit 65.

Here, we will explain an example of the operation of loading soil (cargo) onto a dump truck using the excavator 100 according to this embodiment.

First, the shovel 100 excavates soil with the bucket 6 by controlling the attachment at the excavation position (excavation operation). Next, the shovel 100 rotates the upper rotating body 3 and moves the bucket 6 from the excavation position to the soil discharge position (swing operation). The bed of the dump truck is located below the soil discharge position. Next, the shovel 100 controls the attachment at the soil discharge position to discharge the soil in the bucket 6, thereby loading the soil in the bucket 6 onto the bed of the dump truck (soil discharge operation). Next, the shovel 100 rotates the upper rotating body 3 and moves the bucket 6 from the soil discharge position to the excavation position (swing operation). By repeating these operations, the shovel 100 loads the excavated soil onto the bed of the dump truck.

The weight calculation unit 61 calculates the weight Ws of the soil in the bucket 6. The weight calculation unit 61 calculates the weight of the soil based on the thrust of the boom cylinder 7 and the distance from the pin connecting the upper rotating body 3 and the boom 4 to the center of gravity Gs of the soil. For example, the weight calculation unit 61 calculates the weight of the soil by substituting the thrust of the boom cylinder 7 and the distance from the pin connecting the upper rotating body 3 and the boom 4 to the center of gravity Gs of the soil into the equation for the moment around the pin connecting the upper rotating body 3 and the boom 4.

The maximum load detection unit 62 detects the maximum load of the dump truck to be loaded with soil and sand. For example, the maximum load detection unit 62 identifies the dump truck to be loaded with soil and sand based on the image captured by the imaging device S6. "Based on the image captured by the imaging device S6" means, for example, using information obtained by performing one or more image processing on the image captured by the imaging device S6. Next, the maximum load detection unit 62 detects the maximum load of the dump truck based on the image of the identified dump truck. For example, the maximum load detection unit 62 determines the vehicle type (size, etc.) of the dump truck based on the image of the identified dump truck. The maximum load detection unit 62 has a table that associates vehicle types with maximum loads, and determines the maximum load of the dump truck based on the vehicle type and table determined from the image. Note that the maximum load, vehicle type, etc. of the dump truck may be input by the input device 42, and the maximum load detection unit 62 may determine the maximum load of the dump truck based on the input information of the input device 42.

The load amount calculation unit 63 calculates the weight of the soil loaded on the dump truck. That is, each time the soil in the bucket 6 is discharged onto the bed of the dump truck, the load amount calculation unit 63 adds the weight of the soil in the bucket 6 calculated by the weight calculation unit 61 to calculate the load amount (total weight), which is the total weight of the soil loaded onto the bed of the dump truck. Note that if the dump truck to which the soil is to be loaded becomes a new dump truck, the load amount is reset.

The remaining load calculation unit 64 calculates the remaining load as the difference between the maximum load of the dump truck detected by the maximum load detection unit 62 and the current load calculated by the load calculation unit 63. The remaining load is the remaining weight of soil that can be loaded onto the dump truck.

The center of gravity calculation unit 65 calculates the center of gravity of the soil in the bucket 6. The method for calculating the center of gravity of the soil will be described later.

The display device 40 may display the weight of the soil in the bucket 6 calculated by the weight calculation unit 61, the maximum load of the dump truck detected by the maximum load detection unit 62, the load of the dump truck (the total weight of the soil loaded on the bed) calculated by the load calculation unit 63, and the remaining load of the dump truck (the remaining weight of the soil that can be loaded) calculated by the remaining load calculation unit 64.

The display device 40 may be configured to issue a warning if the load exceeds the maximum load. The display device 40 may be configured to issue a warning if the calculated weight of soil in the bucket 6 exceeds the remaining load. The warning does not have to be displayed on the display device 40, but may be output as sound by the sound output device 43. This makes it possible to prevent soil from being loaded in excess of the maximum load of the dump truck.

Now, referring to FIG. 6, an example of the configuration of the main screen 41V displayed on the display device 40 will be described. The information displayed on the main screen 41V in FIG. 6 includes, for example, information on the weight of soil in the bucket 6 (current weight), the load of the dump truck (accumulated weight), the remaining load of the dump truck (remaining weight), and the maximum load (maximum load weight).

The main screen 41V includes a date and time display area 41a, a driving mode display area 41b, an attachment display area 41c, a fuel consumption display area 41d, an engine control status display area 41e, an engine operating time display area 41f, a coolant temperature display area 41g, a remaining fuel amount display area 41h, an RPM mode display area 41i, a remaining urea water amount display area 41j, a hydraulic oil temperature display area 41k, a camera image display area 41m, a current weight display area 41p, a cumulative weight display area 41q, a remaining weight display area 41s, and a maximum load weight display area 41t.

The travel mode display area 41b, the attachment display area 41c, the engine control status display area 41e, and the rotation speed mode display area 41i are areas that display setting status information, which is information related to the setting status of the excavator 100. The fuel consumption display area 41d, the engine operating time display area 41f, the cooling water temperature display area 41g, the remaining fuel amount display area 41h, the remaining urea water amount display area 41j, the hydraulic oil temperature display area 41k, the current weight display area 41p, and the accumulated weight display area 41q are areas that display operating status information, which is information related to the operating status of the excavator 100.

Specifically, the date and time display area 41a is an area that displays the current date and time. The driving mode display area 41b is an area that displays the current driving mode. The attachment display area 41c is an area that displays an image that represents the end attachment that is currently attached. Figure 6 shows the state in which an image that represents the bucket 6 is displayed.

The fuel efficiency display area 41d is an area that displays fuel efficiency information calculated by the controller 30. The fuel efficiency display area 41d includes an average fuel efficiency display area 41d1 that displays the lifetime average fuel efficiency or the section average fuel efficiency, and an instantaneous fuel efficiency display area 41d2 that displays the instantaneous fuel efficiency.

The engine control status display area 41e is an area that displays the control status of the engine 11. The engine operating time display area 41f is an area that displays the cumulative operating time of the engine 11. The coolant temperature display area 41g is an area that displays the current temperature state of the engine coolant. The remaining fuel amount display area 41h is an area that displays the remaining amount of fuel stored in the fuel tank. The rotation speed mode display area 41i is an area that displays the current rotation speed mode set by the engine rotation speed adjustment dial. The urea water remaining amount display area 41j is an area that displays the remaining amount of urea water stored in the urea water tank. The hydraulic oil temperature display area 41k is an area that displays the temperature state of the hydraulic oil in the hydraulic oil tank.

The camera image display area 41m is an area that displays an image captured by the imaging device S6, which serves as a spatial recognition device. In the example of FIG. 6, the camera image display area 41m displays an image captured by the camera S6B. The image captured by the camera S6B is a rear image that shows the space behind the excavator 100, and includes an image 3a of the counterweight.

The current weight display area 41p is an area that displays the weight (current weight) of the soil in the bucket 6. Figure 6 shows that the current weight is 550 kg.

The accumulated weight display area 41q is an area that displays the load (accumulated weight) of the dump truck. Figure 6 shows that the accumulated weight is 9,500 kg.

The accumulated weight is reset every time the dump truck to be loaded is replaced. In this embodiment, the controller 30 is configured to automatically recognize the replacement of the dump truck and automatically reset the accumulated weight. Specifically, the controller 30 recognizes the replacement of the dump truck using an image captured by the imaging device S6. The controller 30 may recognize the replacement of the dump truck using a communication device. Alternatively, the controller 30 may reset the accumulated weight when a reset button is pressed. The reset button may be a software button or a hardware button arranged on the input device 42, the left operation lever, the right operation lever, or the like.

With this configuration, the shovel 100 can prevent soil and other cargo from being loaded onto the bed of a dump truck in excess of the maximum load weight of the dump truck. When a load exceeding the maximum load weight is detected by weight measurement at the platform, the driver of the dump truck must return to the loading yard and unload some of the cargo from the bed. The shovel 100 can prevent this type of load weight adjustment work from occurring.

The specified period may be, for example, the period from the start of a day's work to the end of that day's work. This is to allow the operator or manager to easily recognize the total weight of the cargo transported during the day's work.

The controller 30 may also be configured to recognize that the soil in the bucket 6 has been loaded onto the bed of the dump truck based on the image captured by the imaging device S6, and then calculate the current weight. This is to prevent soil that has been moved to a location other than the bed of the dump truck from being calculated as soil that has been loaded onto the dump truck.

The controller 30 may determine whether the soil in the bucket 6 has been loaded onto the bed of the dump truck based on the posture of the attachment. Specifically, the controller 30 may determine that the soil has been loaded onto the bed of the dump truck when, for example, the height of the bucket 6 exceeds a predetermined value (e.g., the height of the bed of the dump truck) and the bucket 6 is opened.

The remaining weight display area 41s is an area that displays the remaining weight. The maximum load weight display area 41t is an area that displays the maximum load weight. Figure 6 shows that the accumulated weight is 9,500 kg, the remaining weight is 500 kg, and the maximum load weight is 10,000 kg. However, the display device 40 may display the maximum load weight without displaying the remaining weight.

Messages are displayed in the message display area 41m1. For example, a message is displayed when the accumulated weight exceeds the maximum load weight. This enables the controller 30 to prompt the operator to perform loading and unloading operations, and prevents overloading of the dump truck.

[Method of calculating soil weight in weight calculation unit 61]
Next, a method for calculating the weight of soil (cargo) in the bucket 6 in the weight calculation unit 61 of the shovel 100 according to this embodiment will be described with reference to FIG. 5 as well as with reference to FIGS.

Figures 7 and 8 are schematic diagrams explaining parameters related to the calculation of soil weight. Figure 7 shows the shovel 100, and Figure 8 shows the vicinity of the bucket 6.

Here, the pin connecting the upper rotating body 3 and the boom 4 is defined as P1. The pin connecting the upper rotating body 3 and the boom cylinder 7 is defined as P2. The pin connecting the boom 4 and the boom cylinder 7 is defined as P3. The pin connecting the boom 4 and the arm cylinder 8 is defined as P4. The pin connecting the arm 5 and the arm cylinder 8 is defined as P5. The pin connecting the boom 4 and the arm 5 is defined as P6. The pin connecting the arm 5 and the bucket 6 is defined as P7. Furthermore, the center of gravity of the boom 4 is defined as G1. The center of gravity of the arm 5 is defined as G2. The center of gravity of the bucket 6 is defined as G3. The reference line L2 is a line that passes through pin P7 and is parallel to the opening surface of the bucket 6. Furthermore, the distance between pin P1 and the center of gravity G1 of the boom 4 is defined as D1. The distance between pin P1 and the center of gravity G2 of the arm 5 is defined as D2. The distance between pin P1 and the center of gravity G3 of the bucket 6 is defined as D3. The distance between pin P1 and the center of gravity Gs of the soil is defined as Ds. The distance between pin P1 and the straight line connecting pins P2 and P3 is Dc. The force due to the cylinder pressure of the boom cylinder 7 is Fb. The vertical component of the boom weight (gravity due to the weight of the boom 4) perpendicular to the straight line connecting pin P1 and the boom center of gravity G1 is W1a. The vertical component of the arm weight (gravity due to the weight of the arm 5) perpendicular to the straight line connecting pin P1 and the arm center of gravity G2 is W2a. The weight of the bucket 6 is W6.

As shown in FIG. 7, the position of pin P7 is calculated based on the boom angle and arm angle. That is, the position of pin P7 can be calculated based on the detection values of boom angle sensor S1 and arm angle sensor S2.

As shown in FIG. 8, the positional relationship between the pin P7 and the bucket center of gravity G3 (the angle θ4 between the reference line L2 of the bucket 6 and the line connecting the pin P7 and the bucket center of gravity G3, and the distance D4 between the pin P7 and the bucket center of gravity G3) is a value set according to the type of bucket 6. In other words, the center of gravity calculation unit 65 can estimate the position of the bucket center of gravity G3 based on the detection result of the bucket angle sensor S3.

In addition, the positional relationship between pin P7 and the center of gravity of the soil changes depending on the shape of the bucket 6 and the amount of soil loaded in the bucket 6.

The amount of soil shown in FIG. 8 is the center of gravity Gs1 when loaded into the bucket 6. In this case, the angle θ51 between the reference line L2 of the bucket 6 and the straight line connecting the pin P7 and the center of gravity Gs1 of the soil is the distance D51 between the pin P7 and the center of gravity Gs1 of the soil.

Then, as the amount of soil, in other words the soil weight Ws, decreases, the soil gravity center Gs2, Gs3 changes. This causes the angle θ52 between the line connecting pin P7 and the soil gravity center Gs2, and the angle θ53 between the line connecting pin P7 and the soil gravity center Gs3 to change. Similarly, the distance between pin P7 and the soil gravity center Gs2, and the distance between pin P7 and the soil gravity center Gs3 also change. The change in the soil gravity center Gs in response to the change in the soil weight Ws is based on the shape of the bucket 6.

In this embodiment, the center of gravity position holding table 47A stores, for each shape of the bucket 6, the soil weight Ws and the positional relationship information of the soil center of gravity Gs in association with each other. The positional relationship information of the soil center of gravity Gs includes, for example, the angle θ5 between the line connecting the pin P7 and the soil center of gravity Gs, and the distance D5 between the pin P7 and the soil center of gravity Gs, when the associated soil weight Ws is loaded in the bucket 6. In other words, when the soil weight Ws is estimated, the soil center of gravity Gs can be estimated based on the current inclination of the bucket 6 and the positional relationship information.

Figure 9 is a diagram illustrating the concept of the correspondence relationship held by the center of gravity position holding table 47A according to this embodiment. The horizontal axis represents the soil weight Ws, and the vertical axis represents the distance D5 from the pin P7 to the soil center of gravity Gs.

As shown by line 901 in FIG. 9, the distance D5 from pin P7 to the center of gravity Gs of the soil can be determined from the weight of the soil Ws. As shown in FIG. 9, when the weight of the soil Ws is less than the weight reference value Wt, the distance D5 to the center of gravity Gs of the soil changes abruptly. For this reason, it is preferable to load soil into the bucket 6 so that the weight is equal to or greater than the weight reference value Wt. Note that FIG. 9 only shows the correspondence between the weight of the soil and the distance D5 from pin P7 to the center of gravity Gs of the soil, but when the actual center of gravity position holding table 47A is referenced, not only the distance D5 but also the angle θ5 can be determined.

In other words, when the center of gravity calculation unit 65 calculates the weight of the soil in the bucket 6 (an example of the weight of an object), it can refer to the center of gravity position holding table 47A (an example of table information) to estimate the position of the soil center of gravity Gs (for example, the distance Ds between the pin P1 and the soil center of gravity Gs) based on the calculated soil weight Ws and the detection results of each angle sensor provided on the attachment of the shovel 100.

As described above, by referring to the center of gravity position holding table 47A (an example of table information), the center of gravity calculation unit 65 can determine the distance D5 and angle θ5 from the pin P7 to the center of gravity Gs of the soil from the soil weight Ws. Since the distance Ds is the distance between the pin P1 and the center of gravity Gs of the soil, the distance from the pin P1 to the pin P7 is required in addition to the distance D5 and the angle θ5. The distance from the pin P1 to the pin P7 can be determined by the shape of the boom 4 and the arm 5 and the detection results of each angle sensor (e.g., the boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3). Since the shapes of the boom 4 and the arm 5 are predetermined, the distance from the pin P1 to the pin P7 can be calculated based on the detection results of each angle sensor. Therefore, the center of gravity calculation unit 65 can estimate the distance Ds between the pin P1 and the center of gravity Gs of the soil based on the correspondence relationship in the center of gravity position holding table 47A, the calculated soil weight Ws, and the detection results of each angle sensor attached to the attachment of the shovel 100.

As a result, when the soil weight processing unit 60 subsequently calculates the soil weight Ws, it can use the estimated distance Ds from the pin P1 to the soil center of gravity Gs to accurately calculate the soil weight Ws.

When calculating the soil weight Ws, the position of the soil center of gravity Gs is required. However, before the soil weight Ws is calculated for the first time, the position of the soil center of gravity Gs cannot be estimated.

Therefore, in this embodiment, the storage device 47 pre-stores the initial value of the position of the soil gravity center Gs corresponding to the bucket 6 attached to the shovel 100 (for example, the initial value of the angle θ5 between the line connecting the pin P7 and the soil gravity center Gs, and the initial value of the distance D5 between the pin P7 and the soil gravity center Gs). The initial value of the position of the soil gravity center Gs is a value used to calculate the first soil weight Ws. In this embodiment, the calculation of the soil weight Ws is repeated. In the repeated calculation of the soil weight Ws, the initial value of the position of the soil gravity center Gs is used for the first calculation of the soil weight Ws. In the repeated calculation of the soil weight Ws from the nth (n is 2 or more)th time onwards, the position of the soil gravity center Gs estimated from the soil weight calculated in the n-1th time is used. Here, the center of gravity position holding table 47A may associate the height from the bottom surface of the bucket 6 to the position of the soil gravity center Gs with the soil weight Ws. In this case, the center of gravity calculation unit 65 can calculate the distance Ds from the pin P1 to the center of gravity Gs of the soil using the shape of the bucket 6 set by the bucket shape setting unit 70 and the positional relationship between the bucket 6 and the pin P7.

In this way, the soil weight processing unit 60 calculates the first soil weight Ws11 using the initial value of the position of the soil center of gravity Gs. A specific method for calculating the soil weight Ws using the position of the soil center of gravity Gs will be described later. After the first soil weight Ws11 is calculated, the center of gravity calculation unit 65 estimates the position of the first soil center of gravity Gs11 (the distance Ds between the pin P1 and the soil center of gravity Gs) based on the positional relationship information of the soil center of gravity Gs associated with the calculated first soil weight Ws11 (the angle θ5 between the line connecting the pin P7 and the soil center of gravity Gs, and the distance D5 between the pin P7 and the soil center of gravity Gs) and the detection values of the boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3. The soil weight processing unit 60 then uses the position of the first soil gravity center Gs11 (the distance Ds from the pin P1 to the soil gravity center Gs) to again calculate the second soil weight Ws12.

However, the initial value of the position of the soil gravity center Gs may differ from the actual position of the soil gravity center Gs. Therefore, the first soil weight Ws11 calculated using the initial value of the position of the soil gravity center Gs may differ from the actual soil weight Ws. Therefore, the gravity center calculation unit 65 in this embodiment estimates the position of the first soil gravity center Gs11 corresponding to the calculated first soil weight Ws11 by referring to the gravity center position retention table 47A.

As shown in FIG. 9, the center of gravity position holding table 47A holds the correspondence between the soil weight Ws and the position of the soil center of gravity Gs. The position of the first soil center of gravity Gs11 is a value estimated by using the calculated first soil weight Ws1 and then referring to this center of gravity position holding table 47A. Therefore, the position of the first soil center of gravity Gs11 is considered to be a value closer to the actual position of the soil center of gravity Gs compared to the initial value.

Then, the soil weight processing unit 60 according to this embodiment uses the position of the estimated first soil center of gravity Gs11 to calculate the second soil weight Ws12 again. Since the calculated second soil weight Ws12 uses the estimated first soil center of gravity Gs11, it is considered that the calculated second soil weight Ws12 is closer to the actual soil weight Ws than the first soil weight Ws11. In other words, this embodiment improves the calculation accuracy of the estimated soil center of gravity Gs position and the calculation accuracy of the soil weight Ws by alternately and repeatedly calculating the position of the soil center of gravity Gs based on the soil weight Ws and the calculated soil center of gravity Gs position and the detection result of the thrust of the boom cylinder 7. Therefore, in this embodiment, the soil weight Ws can be calculated with high accuracy. As described above, the specific repetition period may be determined according to the cycle that the controller 30 can execute (for example, in units of 0.1 seconds).

In this way, the center of gravity calculation unit 65 refers to the center of gravity position holding table 47A and estimates the distance Ds between the pin P1 and the center of gravity Gs of the soil based on the soil weight Ws and the detection values of the boom angle sensor S1, arm angle sensor S2, and bucket angle sensor S3. Next, the method of calculating the soil weight Ws will be explained. First, the parameters used other than the soil center of gravity Gs to calculate the soil weight Ws will be explained.

The controller 30 according to the present embodiment calculates the weight Ws of the soil in the bucket 6 based on information based on the shape of the bucket 6 loaded with soil (for example, the center of gravity and bucket weight W3 of the bucket 6) in addition to the output of the detection values of various sensors whose detection results change according to the soil weight Ws of the bucket 6. In this embodiment, a case where a detection value related to the force Fb due to the cylinder pressure of the boom cylinder 7 is used as an example of the detection values of various sensors whose detection results change according to the soil weight Ws of the bucket 6 will be described. In addition, the excavator 100 according to the present embodiment has a boom 4 and an arm 5 between the bucket 6 and the excavator 100 body as attachments. Therefore, when a detection value related to the force Fb due to the cylinder pressure of the boom cylinder 7 is used as the detection value of various sensors whose detection results change according to the soil weight Ws, the weight and shape of the boom 4 and the arm 5 must also be taken into consideration. Note that this embodiment is not limited to the method of using the detection value of the force Fb due to the cylinder pressure of the boom cylinder 7 as the detection value of various sensors whose detection results change depending on the soil weight Ws of the bucket 6, and other detection values (for example, detection values related to the force due to the cylinder pressure of the bucket cylinder 9) may also be used.

Next, we will explain the equation for balance when using the force Fb due to the cylinder pressure of the boom cylinder 7. The equation for balance between each moment around the pin P1 and the boom cylinder 7 can be expressed by the following equation (A1).

WsDs + W1aD1 + W2aD2 + W3D3 = FbDc ... (A1)

When formula (A1) is expanded for the soil weight Ws, it can be expressed as the following formula (A2).

Ws = (FbDc - (W1aD1 + W2aD2 + W3D3)) / Ds ... (A2)

Here, the force Fb due to the cylinder pressure of the boom cylinder 7 is calculated from the detection values output from the boom rod pressure sensor S7R and the boom bottom pressure sensor S7B (an example of a detection unit).

For example, the force Fb (thrust) due to the cylinder pressure of the boom cylinder 7 is expressed by the following formula (A3) based on the pressure-receiving area AR of the rod-side oil chamber of the boom cylinder 7, the boom rod pressure PR, the pressure-receiving area AB of the bottom-side oil chamber of the boom cylinder 7, and the boom bottom pressure PB. The boom rod pressure PR is a value detected by the boom rod pressure sensor S7R. The boom bottom pressure PB is a value detected by the boom bottom pressure sensor S7B. The pressure-receiving area AR of the rod-side oil chamber and the pressure-receiving area AB of the bottom-side oil chamber are determined in advance. The following formula (A3) shows an example of a calculation method for the force Fb (thrust), and other calculation methods may be used.

Fb = AB x PB - AR x PR ... (A3)

The force Fb due to the cylinder pressure is derived by substituting the values detected by the boom rod pressure sensor S7R and the boom bottom pressure sensor S7B into equation (A3). In other words, the values detected (output) from the boom rod pressure sensor S7R and the boom bottom pressure sensor S7B can be considered as detection values that change according to the weight Ws of the soil in the bucket 6.

Among the variables shown in formula (A2), the distance Dc and the vertical component W1a of the boom weight are calculated from the detection value of the boom angle sensor S1. The vertical component W2a of the arm weight and the distance D2 are calculated from the detection values of the boom angle sensor S1 and the arm angle sensor S2, respectively. The distance D1 is a known value. The bucket weight W3 (gravity due to the weight of the bucket 6) is also a known value, and is specifically set by the bucket shape setting unit 70 in accordance with the shape of the bucket 6. The distance D3 is calculated from the detection values of the boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3, as well as the shape of the excavator 100 attachment, and the bucket center of gravity G3 corresponding to the shape of the bucket 6 set by the bucket shape setting unit 70.

The soil weight Ws can therefore be calculated based on known values such as the bucket weight W3, as well as the estimated distance Ds between the pin P1 and the soil center of gravity Gs, the detection value of the boom rod pressure sensor S7R, the detection value of the boom bottom pressure sensor S7B, the bucket angle (bucket angle sensor S3), the boom angle (detection value of the boom angle sensor S1), and the arm angle (detection value of the arm angle sensor S2).

In other words, the weight calculation unit 61 can calculate the weight of the soil Ws based on the distance Ds to the soil gravity center Gs estimated by the center of gravity calculation unit 65, the detection value of the cylinder pressure of the boom cylinder 7, and the detection value of the angle sensor.

In addition, the determination of whether the excavator 100 is performing a predetermined operation using the attachment can be derived from the estimated result of the posture of the attachment based on the detection value of the cylinder pressure of the cylinder (e.g., the boom cylinder 7, the arm cylinder 8, or the bucket cylinder 9), or the estimated result of the operation of the attachment based on the detection value of the pilot pressure for the boom 4, the arm 5, or the bucket 6. For example, when the detection value of the cylinder pressure changes, the change in the posture of the attachment can be estimated, and the operation of the attachment can be estimated from the change in posture. As another example, when the detection value of the pilot pressure changes, the operation performed by the operator can be estimated, and the operation of the attachment performed according to the operation can be estimated. An example of the predetermined operation is the operation of closing the bucket 6. For example, depending on whether the operation of closing the bucket 6 is being performed, it may be estimated whether an excavation operation is being performed. The determination of whether a predetermined operation is being performed is not limited to the method of using the cylinder pressure or the pilot pressure, and may be based on the detection value of an angle sensor (e.g., the boom angle sensor S1, the arm angle sensor S2, or the bucket angle sensor S3). The pilot pressure for the boom 4 is a pressure that changes depending on the direction and amount of operation of the boom operation lever of the operating device 26, and is the pressure of the hydraulic oil acting on the pilot port of the control valve 175 corresponding to the boom cylinder 7. The same applies to the pilot pressure for the arm 5 and the pilot pressure for the bucket 6.

Figure 10 is a flowchart showing the processing procedure for determining the weight of the load loaded in the bucket 6 in the controller 30 according to this embodiment. The example shown in Figure 10 shows the processing after the excavation operation by the shovel 100 is completed.

First, the weight calculation unit 61 determines whether the condition for starting weight calculation is met after the excavation operation is completed (S1001). If it is determined that the condition for starting weight calculation is not met (S1001: NO), the process of S1001 is repeated. The interval at which the process of S1001 is repeated may be any interval, and may be, for example, a cycle that the controller 30 can execute (for example, in units of 0.1 seconds). The condition for starting weight calculation may be any condition, and may be, for example, the start of lifting the bucket 6. Whether or not lifting of the bucket 6 has started can be estimated based on the detection value of the cylinder pressure of the boom cylinder 7 or the pilot pressure for the boom 4. Note that whether or not lifting of the bucket 6 has started is not limited to estimation based on the detection value of the cylinder pressure of the boom cylinder 7 or the pilot pressure for the boom 4, and may be estimated based on, for example, the detection value of the boom angle sensor S1.

On the other hand, if it is determined that the conditions for starting weight calculation are met (S1001: YES), the weight calculation unit 61 calculates the weight of the soil in the bucket 6 (an example of the weight of an object) Ws based on the detection values of the various angle sensors provided on the attachment, as well as the thrust of the boom cylinder 7 (force Fb due to cylinder pressure) and the initial value of the soil center of gravity Gs stored in the memory device 47 (an example of the position of the center of gravity of an object that has been preset) (S1002).

Then, the center of gravity calculation unit 65 refers to the center of gravity position holding table 47A and calculates the distance Ds from the pin P1 to the center of gravity Gs of the soil in the bucket 6, which corresponds to the calculated weight Ws of the soil (S1003). Specifically, the center of gravity calculation unit 65 calculates the distance Ds from the pin P1 to the center of gravity Gs of the soil based on the positional relationship information associated with the weight Ws of the soil (the angle θ5 between the pin P7 and the straight line connecting the center of gravity Gs of the soil, and the distance D5 between the pin P7 and the center of gravity Gs of the soil) and the detection values of the boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3.

Then, the weight calculation unit 61 calculates the weight of the soil (an example of the weight of an object) Ws in the bucket 6 based on the detection values of the various angle sensors, as well as the thrust of the boom cylinder 7 (force Fb due to the cylinder pressure) and the distance Ds to the soil center of gravity Gs calculated in S1003 (S1004).

Then, the weight calculation unit 61 determines whether or not the weight determination condition (one example of a predetermined condition) is met while the bucket 6 is being lifted (S1005). If it determines that the amount determination condition is not met (S1005: NO), the process repeats from S1003. The weight determination condition may be any condition, and may be, for example, that the lifting height of the bucket 6 exceeds a predetermined reference value.

On the other hand, if it is determined that the weight determination conditions are met (S1005: YES), the process ends. If it is determined that the weight determination conditions are met, the determined soil weight Ws (an example of the weight of an object) may be, for example, the last calculated value or the average value of multiple soil weights calculated near the last.

In this embodiment, calculation of the soil weight Ws and calculation of the soil center of gravity Gs are alternately repeated. By repeating this process, the accuracy of the calculated position of the soil center of gravity Gs and the soil weight Ws can be improved. Therefore, the accuracy of the determined soil weight Ws can be improved.

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The excavator 100 (an example of a work machine) according to the embodiment described above has a configuration that allows input of the shape of the bucket 6. Therefore, in the embodiment described above, by estimating the position of the center of gravity of the soil loaded in the bucket 6 while taking into account the shape of the bucket 6, it is possible to improve the accuracy of estimating the position of the center of gravity of the soil.

In the above-described embodiment, the center of gravity position holding table 47A, which is held for each shape of the bucket 6, is used as a method for taking into account the shape of the bucket 6. In other words, in the above-described embodiment, the position of the center of gravity of the soil is realized by referring to the center of gravity position holding table 47A, taking into account the shape of the bucket 6. Note that the method for estimating the center of gravity Gs of the soil taking into account the shape of the bucket 6 is not limited to the method using the center of gravity position holding table 47A, and other methods may be used.

In the above-described embodiment, the force Fb due to the cylinder pressure of the boom cylinder 7, which is based on the detection values output from the boom rod pressure sensor S7R and the boom bottom pressure sensor S7B (an example of a detection unit), changes depending on the weight of the soil.

The weight calculation unit 61 according to the embodiment described above identifies the soil gravity center Gs by referring to the center of gravity position holding table 47A, and then calculates the soil weight Ws based on the soil gravity center Gs and the detection value related to the force Fb due to the cylinder pressure of the boom cylinder 7. In other words, in the embodiment described above, the accuracy of calculating the soil weight Ws can be improved by referring to the center of gravity position holding table 47A and taking into account the shape of the bucket 6.

In the above-described embodiment, an example has been described in which the weight calculation unit 61 identifies the soil gravity center Gs by referring to the center of gravity position holding table 47A, and then calculates the soil weight Ws based on the soil gravity center Gs and the detection value related to the force Fb due to the cylinder pressure of the boom cylinder 7. However, the above-described embodiment is not limited to a method that refers to the center of gravity position holding table 47A and takes into account the shape of the bucket 6. For example, the soil weight Ws may be calculated taking into account the soil gravity center determined according to the shape of the bucket 6.

Although the embodiment of the work machine according to the present invention has been described above, the present invention is not limited to the above embodiment. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. Naturally, these also fall within the technical scope of the present invention.

100 Shovel 1 Lower traveling body 2 Rotation mechanism 3 Upper rotating body 4 Boom (attachment)
5 Arm (attachment)
6. Bucket (work tool)
7 Boom cylinder 8 Arm cylinder 9 Bucket cylinder 30 Controller 47 Storage device 47A Center of gravity position holding table 50 Machine guidance section 51 Position calculation section 52 Distance calculation section 53 Information transmission section 54 Automatic control section 55 Swing angle calculation section 56 Relative angle calculation section 60 Soil weight processing section 61 Weight calculation section 62 Maximum load amount detection section 63 Load amount calculation section 64 Remaining load amount calculation section 65 Center of gravity calculation section 70 Bucket shape setting section

Claims (9)

The device is configured to be capable of inputting a shape of a bucket provided at the tip of an attachment attached to a shovel, and to calculate the weight of an object in the bucket based on the inputted shape of the bucket and an output of a detection unit whose detection result changes according to the weight of the object in the bucket.
Excavator control device. a storage device that stores table information that associates the weight of the object with the position of the center of gravity of the object according to the shape of the bucket;
when the weight of the object in the bucket is calculated, the table information is referred to, and a position of a center of gravity of the object is identified based on the calculated weight of the object, and then the weight of the object in the bucket is calculated again based on the identified position of the center of gravity of the object and an output of the detection unit.
The control device for a shovel according to claim 1. The method is configured to alternately calculate the weight of the object based on the identified position of the center of gravity of the object and the output of the detection unit, and identify the position of the center of gravity of the object based on the calculated weight of the object.
The control device for a shovel according to claim 2. A lower running body;
An upper rotating body rotatably mounted on the lower traveling body;
An attachment attached to the upper rotating body;
A bucket provided at the tip of the attachment;
a control device that is configured to allow a shape of the bucket to be input and to calculate a weight of the object in the bucket based on the input shape of the bucket and an output of a detection unit, the detection result of which changes depending on the weight of the object in the bucket. a storage device that stores table information that associates the weight of the object with the position of the center of gravity of the object according to the shape of the bucket;
When the control device calculates the weight of the object in the bucket, the control device refers to the table information, identifies a position of a center of gravity of the object based on the calculated weight of the object, and then recalculates the weight of the object in the bucket based on the identified position of the center of gravity of the object and an output of the detection unit.
The shovel according to claim 4. The control device alternately calculates a weight of the object based on the identified position of the center of gravity of the object and the output of the detection unit, and identifies the position of the center of gravity of the object based on the calculated weight of the object.
The shovel according to claim 5. when starting to lift the bucket, the control device calculates a weight of the object in the bucket based on a preset position of a center of gravity of the object and an output of the detection unit.
The shovel according to claim 6. The control device terminates the calculation of the weight of the object and the identification of the position of the center of gravity of the object when a predetermined condition is satisfied while the bucket is being lifted.
The shovel according to claim 6. The control device receives the shape of the bucket from an operation device, an external device, or an imaging device.
The shovel according to claim 4.

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