WORK MACHINE

Abstract

A work machine capable of loading a loading object into a container with reduced unevenness. The work machine includes a controller, which selects a release motion in accordance with the state in the container from a plurality of candidate motions. The plurality of candidate motions are different from each other in a planar area of the soil and sand to be loaded into the container by each candidate motion and spread.

Description

TECHNICAL FIELD

The present invention relates to a work machine including a bucket.

BACKGROUND ART

Patent Literature 1 discloses an excavator including a bucket. The excavator is capable of discharging soil from the bucket along a target trajectory, which is set along the front-rear direction of the loading platform of a dump truck.

The soil discharge from the excavator, however, involves a variation in soil in the front-rear direction of the loading platform depending on the soil property and the opening degree of the bucket. This hinders the soil (or other soil and sand) from being evenly loaded on the entire loading platform (or other container).

CITATION LIST

Patent Literature

• • Patent Literature 1: WO2021/054436

Summary of Invention

It is an object of the invention to provide a work machine capable of loading a loading object into a container with reduced unevenness.

Provided is a work machine including a machine body, an attachment and a controller. The attachment includes a bucket capable of holding a loading object, attached to the machine body. The controller automatically makes the attachment repeat a holding motion and a release motion alternately. The holding motion is a motion of holding the loading object in the bucket. The release motion is a motion of releasing the loading object held in the bucket into the container. The release motion is selected from among a plurality of candidate motions, which are different from each other in a planar area, which is an area in plan view, of the loading object to be released into the container by each candidate motion and spread in the container. The controller is configured to select the release motion from the plurality of candidate motions in accordance with a state in the container.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side view of a work machine according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing the main components of the work machine.

FIG. 3 is a side view showing a state where the first loading of soil and sand from the work machine into the loading platform of a dump truck has been performed.

FIG. 4 is a plan view showing the state shown in FIG. 3.

FIG. 5 is a side view showing a state where the second loading of soil and sand from the work machine into the loading platform has been performed.

FIG. 6 is a plan view showing the state shown in FIG. 5.

FIG. 7 is a side view showing a space left on the rear side of the soil and sand after the second loading of the soil and sand.

FIG. 8 is a plan view showing the space shown in FIG. 7.

FIG. 9 is a side view showing a state where the third loading of soil and sand from the work machine into the loading platform has been performed.

FIG. 10 is a plan view showing the state shown in FIG. 9.

FIG. 11 is a side view of the work machine and the dump truck, showing a first candidate motion to be performed by an attachment of the work machine and the soil and sand that have been loaded into the loading platform of the dump truck by the first candidate motion.

FIG. 12 is a plan view of the work machine and the dump truck, showing the soil and sand that have been loaded into the loading platform by the first candidate motion.

FIG. 13 is a side view of the bucket of the attachment, showing the former half of a second candidate motion.

FIG. 14 is a side view of the bucket, showing the latter half of the second candidate motion.

FIG. 15 is a side view of the work machine and the dump truck, showing a third candidate motion to be performed by an attachment of the work machine and the soil and sand that have been loaded into the loading platform of the dump truck by the third candidate motion.

FIG. 16 is a plan view of the work machine and the dump truck, showing the soil and sand that have been loaded into the loading platform by the third candidate motion.

FIG. 17 is a side view of the work machine and the dump truck, showing the state where a space is left on a rear side portion of the loading platform.

FIG. 18 is a plan view of the work machine and the dump truck, showing the state shown in FIG. 17.

FIG. 19 is a side view of the work machine and the dump truck, showing the state where a space has been caused in an intermediate portion of the loading platform.

FIG. 20 is a plan view of the work machine and the dump truck, showing the state shown in FIG. 19.

FIG. 21 is a plan view of the dump truck, showing a case where the shape of the soil and sand having been loaded into the loading platform is lower than the target shape.

FIG. 22 is a side view of the dump truck, showing a case where the shape of soil and sand on the rear side portion of the loading platform is lower than the target shape.

FIG. 23 is a plan view of the work machine and the dump truck, showing an example in which the longitudinal direction of the attachment of the work machine and the longitudinal direction of the loading platform of the dump truck are orthogonal to each other.

FIG. 24 is a side view of a work machine and a dump truck according to a second embodiment of the present invention, showing a state where a space has been caused at a rear side portion of the loading platform of the dump truck.

FIG. 25 is a plan view of the work machine and the dump truck according to the second embodiment, showing the state shown in FIG. 24.

FIG. 26 is a side view of the work machine and the dump truck according to the second embodiment, showing an example in which a release motion is selected based on the release position in the loading platform of the dump truck.

DETAILED DESCRIPTION

Below will be described a preferred embodiment of the present invention with reference to the drawings.

FIG. 1 is a side view of a work machine 1 according to a first embodiment of the present invention. The work machine 1 includes an attachment 30 shown in FIG. 1, by which work is performed. The work machine 1 illustrated in FIG. 1 is a hydraulic excavator. The attachment 30 includes a bucket 33, and the work machine 1 performs holding a loading object by the bucket 33 and releasing the loading object from the bucket 33 into a container. In the present embodiment, the container is a loading platform 71 of a dump truck 70 shown in FIG. 3 and the like. The container, alternatively, may be a soil-and-sand pit or the like. The loading object in the present embodiment is soil and sand. The loading object, alternatively, may be a stone, a waste (such as industrial waste) or the like.

The work machine 1 includes a machine body 24, an attachment 30 and a plurality of cylinders 40, the machine body 24 including a lower traveling body 21 and an upper turning body 22.

The lower traveling body 21 is a part capable of traveling on the ground, including, for example, a pair of left and right crawlers. The upper turning body 22 is mounted on the lower traveling body 21 through a turning device 25 capably of turning. The upper turning body 22 includes a cab (operation chamber) 23 located at the front side portion thereof.

The attachment 30 is attached to the upper turning body 22 capably of performing a work motion. The attachment 30 includes a boom 31, an arm 32 and a bucket 33. The boom 31 is attached to the upper turning body 22 capably of vertical and rotational movement (capably of derricking). The arm 32 is attached to the boom 31 capably of vertical and rotational movement. The bucket 33 is attached to the arm 32 capably of rotational movement in the front-rear direction, serving as a tip attachment that is a tip part of the attachment 30. The bucket 33 is a work member capable of performing work on soil and sand (loading object), such as excavation, leveling, rake and the like. The bucket 33 is capable of holding soil and sand which is the loading object.

The plurality of cylinders 40 are arranged to hydraulically bring the boom 31, the arm 32, and the bucket 33 of the attachment 30 into respective rotational movements. Each of the cylinders 40 is a hydraulic cylinder to be hydraulically driven to perform expansion and contraction motions. The plurality of cylinders 40 include a boom cylinder 41, an arm cylinder 42 and a bucket cylinder 43.

The boom cylinder 41 is disposed to rotationally move the boom 31 with respect to the upper turning body 22. The boom cylinder 41 has a proximal end and a distal end opposite to the proximal end. The proximal end is connected to the upper turning body 22 capably of rotational movement. The distal end is connected to the boom 31 capably of rotational movement.

The arm cylinder 42 is disposed to rotationally move the arm 32 with respect to the boom 31. The arm cylinder 42 has a proximal end and a distal end opposite to the proximal end. The proximal end is connected to the boom 31 capably of rotational movement. The distal end is connected to the arm 32 capably of rotational movement.

The bucket cylinder 43 is disposed to rotationally move the bucket 33 with respect to the arm 32. The bucket cylinder 43 has a proximal end and a distal end opposite to the proximal end. The proximal end is connected to the arm 32 capably of rotational movement. The distal end is connected to a link member 34 capably of rotational movement, and the link member 34 is connected to the bucket 33 capably of rotational movement.

The work machine 1 further includes a state acquisition device 27 shown in FIG. 2. The state acquisition device 27 acquires state information. The state information, in the present embodiment, is information about a state in the container, that is, in the loading platform 71 of the dump truck 70. The state acquisition device 27 is disposed, for example, on the cab 23. In the present embodiment, the state acquisition device 27 is a LiDAR (Light Detection and Ranging or Laser Imaging Detection and Ranging). The state acquisition device 27 performs scanning in a scanning direction for acquiring the state information, the scanning direction kept frontward of the cab 23. The state acquisition device 27 may be attached to the attachment 30 (for example, the boom 31) or the upper turning body 22.

The state acquisition device 27 acquires point group data (three-dimensional point group) that indicates a distance from the position where the state acquisition device 27 is disposed to the inside of the loading platform 71 of the dump truck 70. The point group data acquired by the state acquisition device 27 allows the state in the loading platform 71 to be determined based on the point group data. The acquisition of the information about the state in the loading platform 71, namely, the state information, allows the position and amount of soil and sand loaded into the loading platform 71 to be determined.

The state acquisition device 27 is not limited to the LiDAR. The state acquisition device 27 may be, for example, a TOF (Time of flight) sensor or a stereo camera.

FIG. 2 shows the main components of the work machine 1. The components include a controller 11, a communication device 12 and a storage device 13 in addition to the turning device 25, the attachment 30 and the state acquisition device 27.

The communication device 12 is capable of communication with the mobile terminal 90. The mobile terminal 90 is a terminal to be operated by an operator at a work site, for example, being a tablet terminal. The mobile terminal 90, alternatively, may be a smartphone or the like.

The storage device 13 stores a target shape of soil and sand to be loaded into the loading platform 71 of the dump truck 70.

To the controller 11 is input the point group data acquired by the state acquisition device 27.

The controller 11 automatically operates the turning device 25 and the attachment 30 so as to make the work machine 1 perform a predetermined automatic operation motion. In short, the controller 11 performs the automatic operation of the work machine 1. In the present embodiment, the automatic operation motion includes a motion for repeating excavation, lifting and turning, soil removal and return turning, in this order.

In other words, the controller 11 automatically operates the attachment 30 to make the attachment 30 repeat a holding motion and a release motion alternately. The holding motion is a motion of holding soil and sand in the bucket 33, including the “excavation” and the “lifting and turning”. The release motion is a motion of releasing soil and sand held in the bucket 33 into the loading platform 71 of the dump truck 70, including the “soil removal”.

In the present embodiment, the release motion is performed three times. FIGS. 3 and 4 show the state where soil and sand E1 has been loaded into the loading platform 71 by the first release motion; FIGS. 5 and 6 show the state where soil and sand E2 has been loaded into the loading platform 71 by the second release motion; FIGS. 7 and 8 show a space 73 left in the loading platform 71 after the second release motion; and FIGS. 9 and 10 show the state where soil and sand E3 has been loaded into the loading platform 71 by the third release motion. In the illustrated release motions, the longitudinal direction, i.e., the front-rear direction, of the loading platform 71 and the longitudinal direction of the attachment 30 are parallel with each other. Hence, the release motion is performed at a position where the work machine 1 is opposed to the rear end (right end in FIGS. 3 to 10) of the loading platform 71. The work machine 1, therefore, can shift the soil removal position along the longitudinal direction of the loading platform 71.

In the example shown in FIGS. 3 to 10, the same type of release motions are performed three times. In each release motion, the bucket 33 is rotationally moved around the proximal end 33a of the bucket 33 while the position of the proximal end 33a of the bucket 33 with respect to the machine body 24 is fixed in the longitudinal direction of the attachment 30. The proximal end 33a is an arm connection part, which is a part of the bucket 33 to be connected to the arm 32. With respect to the longitudinal direction (front-rear direction) of the loading platform 71, the soil and sand E1 is loaded into the front side portion (the left side portion in the drawing) of the loading platform 71 by the first release motion; the soil and sand E2 is loaded into the intermediate portion of the loading platform 71 by the second release motion; and the soil and sand E3 is loaded into the rear side portion (the right side portion in the drawing) of the loading platform 71 by the third release motion.

In the example shown in FIGS. 3 to 10, the planar area, which is an area in plan view, of the space 73 left on the rear side portion of the loading platform 71 as shown in FIGS. 7 and 8 at the time when the second release motion is ended is smaller than the planar area of each of the soil and sand E1 and E2 that are loaded into the loading platform 71 by the first and second release motions, respectively. Hence, the third release motion, if being the same type of release motion as the first and second release motions as shown in FIGS. 9 and 10, would cause the soil and sand E3 loaded by the third release motion to be put over the soil and sand E2 having been loaded by the second release motion. This increases the unevenness in the height of the soil and sand in the loading platform 71.

As a means for reducing the unevenness, the controller 11 is configured to select the motion according to the state in the loading platform 71 from among a plurality of preset candidate motions, as the release motion to be actually performed. The plurality of candidate motions are different from each other in a planar area of the soil and sand to be released into the loading platform 71 by the candidate motion and spread in the loading platform 71. In the present embodiment, the plurality of candidate motions include a first candidate motion Ma, a second candidate motion Mb and a third candidate motion Mc. The number of candidate motions and the specific detail of each candidate motion according to the present invention are, however, not limited.

FIGS. 11 and 12 show the state where soil and sand E has been loaded into the loading platform 71 by the first candidate motion Ma. The first candidate motion Ma is the rotational movement of the bucket 33 in an opening direction around the proximal end 33a, which is the arm connection part. The first candidate motion Ma, thus, is a motion of releasing soil and sand while fixing the position of a part of the bucket 33 (the proximal end 33a) with respect to the machine body 24 in the longitudinal direction of the attachment 30. By the first candidate motion Ma, the soil and sand can be loaded into a relatively small range in the loading platform 71.

FIGS. 13 and 14 show the second candidate motion Mb. The second candidate motion Mb includes the rotational movement of the bucket 33 to a vertical posture in which the opening surface of the bucket 33 extends vertically as indicated by a solid line in FIG. 13, and the subsequent respective rotational movements of the boom 31, the arm 32, and the bucket 33 to move the bucket 33 from the vertical posture to a posture in which the opening surface of the bucket 33 is directed downward as indicated by a solid line in FIG. 14 while keeping the position of the tip 33b of the bucket 33 in the front-rear direction with respect to the machine body 24. The front-rear direction is a direction parallel to the direction of the rotational movement of the bucket 33 with respect to the arm 32. The second candidate motion Mb, thus, is a motion of releasing the soil and sand in the bucket 33 downward while fixing the position of a part of the bucket 33 (tip 33b) with respect to the machine body 24 in the longitudinal direction of the attachment 30. In the second candidate motion Mb, the position at which soil and sand is released is kept substantially constant during a period from the start to the end of the rotational movement of the bucket 33. Hence, the second candidate motion Mb is suitable for loading soil and sand to the fixed point of the loading platform 71. The planar area Ab of the soil and sand E to be loaded into the loading platform 71 by the second candidate motion Mb (the area of the soil and sand E shown in FIG. 14) is smaller than the area Aa provided by the first candidate motion Ma. (the area of the soil and sand E shown in FIG. 12).

FIGS. 15 and 16 show the state where soil and sand E has been loaded into the loading platform 71 by the third candidate motion Mc. The third candidate motion Mc is the combination of the rotational movement of the bucket 33 in the opening direction and the movement of the bucket 33 along the longitudinal direction (front-rear direction) of the loading platform 71. The third candidate motion Mc is, thus, a motion of releasing the soil and sand in the bucket 33 downward while moving the bucket 33 in the longitudinal direction of the attachment 30. As shown in FIGS. 15 and 16, the longitudinal direction of the loading platform 71 is parallel to the longitudinal direction of the attachment 30. The longitudinal direction of the loading platform 71 may be orthogonal to the longitudinal direction of the attachment 30. In the latter case, the soil and sand E is released while the bucket 33 is moved along the width direction of the loading platform 71 (the direction orthogonal to the longitudinal direction, i.e., the left-right direction). The planar area Ac of the soil and sand E to be loaded in the loading platform 71 by the third candidate motion Mc (the area of the soil and sand E shown in FIG. 16) is larger than the area Aa provided by the first candidate motion Ma (shown in FIG. 12). Hence, the third candidate motion Mc allows soil and sand to be loaded over a relatively large region in the loading platform 71.

The controller 11 selects the candidate motion according to the state in the loading platform 71 from among the first to third candidate motions Ma to Mc, as the release motion to be actually performed. In other words, the controller 11 makes the selection of the candidate motion, that is, the change of the type of the release motion, based on the state information acquired by the state acquisition device 27, which is the information about the state in the loading platform 71.

Below will be described an example of selection from among the plurality of candidate motions, that is, an example of change of the type of the release motion, with reference to FIGS. 17 and 18. FIGS. 17 and 18 are side views of the work machine 1 and the dump truck 70, showing the state where a space 75 has been caused in a rear side portion of the loading platform 71. The state is caused by the first loading of the first soil and sand into the front side portion (left side portion in the drawing) of the loading platform 71 by the first candidate motion Ma and the second loading of the second soil and sand into the intermediate portion of the loading platform 71 by the first candidate motion Ma, wherein the space 75 is left in the rear side portion of the loading platform 71 (right side portion in FIGS. 17 and 18) on the rear side of the soil and sand E2. Based on this state, further performed is the third loading of soil and sand into the space 75 by the next release motion. The planar area of the space 75, however, is smaller than the planar area of the soil and sand E1 according to the first loading, that is, the area Aa provided by the first candidate motion Ma. Hence, the third loading of soil and sand into the space 75, if also performed by the first candidate motion Ma, would cause the soil and sand according to the third loading to cover the soil and sand E2 that has been already loaded in the intermediate portion of the loading platform 71 (that is, the soil and sand E2 according to the second loading), which increases the evenness in the height of the soil and sand in the loading platform 71.

To solve such a problem, the following is executed. The state acquisition device 27 acquires information about the planar area of the space 75 as state information about a state in the loading platform 71. Based on the information, the controller 11 selects the second candidate motion Mb which the area corresponds to is smaller than the planar area of the space 75, as the third release motion. In summary, the type of the third release motion is changed from the first candidate motion Ma, which is the second release motion, to the second candidate motion Mb. This causes the loading of soil and sand into the space 75 to be performed by the second candidate motion Mb. This effectively reduces the unevenness in the soil and sand E3 to be loaded in the space 75. Thus, the direct acquisition of the state information, that is, information about the state in the loading platform 71, provided by the state acquisition device 27, enables the selection of the release motion from among the plurality of candidate motions Ma to Mc to be accurately performed.

The part where the space 75 is left is not limited to the rear side portion of the loading platform 71. The space 75 may be left, for example, in the intermediate portion of the loading platform 71 as shown in FIGS. 19 and 20. In the state shown in FIGS. 19 and 20, the soil and sand E1 is loaded on the front side portion (left side portion in the drawing) of the loading platform 71 by the first candidate motion Ma, and subsequently the soil and sand E2 is loaded also by the first candidate motion Ma into the rear side portion (right side portion in the drawing) of the loading platform 71 at a position separated rearward from the soil and sand E1 by the space 75. This state requires soil and sand to be loaded into the space 75 in the immediate portion of the loading platform 71 by the next third release motion. The planar area of the space 75 is also smaller than the area Aa corresponding to the first candidate motion Ma and equal to or more than the area Ab corresponding to the second candidate motion Mb, like the space 75 shown in FIGS. 17 and 18. Also in this case, therefore, the controller 11 selects the second candidate motion Mb as the third release motion. The type of the third release motion, thus, is changed from the first candidate motion Ma to the second candidate motion Mb. This causes soil and sand to be loaded into the space 75 by the second candidate motion Mb.

The space 75 is not limited to an empty space in which no soil and sand is loaded all over the vertical region. For example, there may be a space left above the soil and sand having been loaded by a level lower than that of the other regions.

As shown in FIGS. 21 and 22, which are side views of the dump truck 70, the controller 11 may serve as a shape setting means for setting a target shape 76 of the soil and sand to be loaded in the loading platform 71. The target shape 76 is stored in the storage device 13. The state acquisition device 27 acquires the shape of soil and sand having been loaded in the loading platform 71 at the present time, namely, a current shape 77, as state information that is information about the state in the loading platform 71. The controller 11 performs determination of the type of the next release motion, that is, selection from the first to third candidate motions Ma to Mc, based on comparison of the current shape 77 acquired by the state acquisition device 27 with the target shape 76 set in advance as described above.

For example, when the upper surface of the soil and sand actually loaded on the loading platform 71 is lower than the target shape 76 throughout the loading platform 71 as shown in FIG. 21, the controller 11 selects the third candidate motion Mc as the next release motion to make the loading of soil and sand performed over the entire loading platform 71 by the third candidate motion Mc. This enables the shape of the soil and sand loaded on the loading platform 71 to be made closer to the target shape 76.

On the other hand, for example, when the upper surface of the soil and sand in the rear side portion (right side portion in the drawing) of the loading platform 71 is lower than the target shape 76 as shown in FIG. 22, the controller 11 selects the second candidate motion Mb as the next release motion to make the loading of the loading of the soil and sand performed into the rear side portion of the loading platform 71 by the second candidate motion Mb. This enables the shape of the soil and sand loaded into the loading platform 71 to be made closer to the target shape 76.

In each of the examples shown in FIGS. 17 to 22, the longitudinal direction (front-rear direction) of the loading platform 71 and the longitudinal direction of the attachment 30 are parallel, that is, the work machine 1 is located at a position where the work machine 1 is opposed to the rear end of the loading platform 71; however, the relative position of the work machine 1 to the loading platform 71 is not limited. The longitudinal direction of the loading platform 71 may intersect the longitudinal direction of the attachment 30. FIG. 23 shows an example in which the longitudinal direction of the loading platform 71 is orthogonal to the longitudinal direction of the attachment 30, that is, an example in which the work machine 1 is located at a position where the work machine 1 is opposed to the side surface of the loading platform 71. In the example, the work machine 1 can perform a motion for moving the soil removal position in a width direction (a direction orthogonal to the longitudinal direction) of the loading platform 71. In the state shown in FIG. 23, the soil and sand E is loaded by the first candidate motion Ma on the back side in the width direction of the loading platform 71 while a space 78 is left on the front side in the width direction of the loading platform 71. If the planar area of the space 78 is smaller than the area Aa corresponding to the first candidate motion Ma and equal to or greater than the area Ab corresponding to the second candidate motion Mb, the controller 11 changes the type of the next release motion from the first candidate motion Ma to the second candidate motion Mb. This causes the loading of soil and sand into the space 78 to be performed by the second candidate motion Mb. In the example shown in FIG. 23, the loading of the soil and sand E to the back side in the width direction by the first candidate motion Ma and the loading of soil and sand to the space 78 on the front side of the soil and sand E by the second candidate motion Mb are repeated with the shift of the soil removal position in the longitudinal direction of the loading platform 71.

As has been described, according to the work machine 1 of the present embodiment, as shown in, for example, FIG. 17, FIG. 18 and FIG. 19, FIG. 20, the release motion to be performed is selected from among the first to third candidate motions Ma to Mc in accordance with the state in the loading platform 71. The first to third candidate motions Ma to Mc are different from each other in the area of soil and sand loaded into the loading platform 71 by the candidate motion and spread in the loading platform 71. This allows the area of soil and sand spread in the loading platform 71 to be changed by the change of the type of the release motion among the first to third candidate motions Ma to Mc in accordance with the state in the loading platform 71. For example, in the case where the planar area of the empty space in the loading platform 71 is acquired as information about the state in the loading platform 71, namely, the state information, a candidate motion in which the area is small is selected as the release motion for loading soil and sand into the empty space, if the planar area of the empty space is small. This enables soil and sand to be loaded into the empty space in the loading platform 71 with reduced unevenness. Thus, the selection of the release motion according to the state in the loading platform 71 enables soil and sand to be loaded into the entire loading platform 71 with reduced unevenness.

As shown in FIGS. 11 to 14, each of the first and second candidate motions Ma, Mb is a motion of releasing soil and sand while fixing the relative position of a part of the bucket 33 to the machine body 24 in the longitudinal direction of the attachment 30. By the motion, soil and sand can be loaded into a relatively narrow region in the loading platform 71.

On the other hand, as shown in FIGS. 15 and 16, the third candidate motion Mc is a motion of releasing soil and sand while moving the bucket 33 in the longitudinal direction of the attachment 30. By the motion, soil and sand can be loaded into a relatively wide range in the loading platform 71.

Besides, the state acquisition device 27, which directly acquires state information that is information about the state in the loading platform 71, enables the selection from among the plurality of candidate motions (the first to third candidate motions Ma to Mc in the embodiment) to be accurately performed.

Specifically, for example, as shown in FIGS. 17 to 20, the state acquisition device 27 acquires the planar area of a space in the loading platform 71 as the state information. Based on the thus acquired area, performed is the selection of the release motion from the plurality of candidate motions. For example, when the planar area of the space into which the soil and sand is to be loaded by the next release motion is small, as the next release motion is selected a candidate motion by which soil and sand is loaded into the loading platform 71 within a small planar arca. This enables soil and sand to be loaded into a space corresponding to the next release motion with reduced unevenness.

In the example shown in FIGS. 21 and 22, the shape of the soil and sand having been loaded in the loading platform 71 at the present time is acquired as the state information. Based on the comparison of the thus acquired shape of the soil and sand with the target shape 76, the selection of the release motion from among the plurality of candidate motions is performed. For example, the selection of the release motion is performed so as to make the shape of the soil and sand to be loaded in the loading platform 71 close to the target shape 76. This enables the shape of the soil and sand to be loaded into the loading platform 71 to be made closer to the target shape 76.

Next will be described a second embodiment of the present invention with reference to FIGS. 24 and 25. There will be omitted description about the configuration comminto the first embodiment and the effect achieved thereby, and mainly described are the points different from those of the first embodiment. The same member as in the first embodiment is denoted by the same reference numerals as those in the first embodiment.

In contrast to the work machine 1 of the first embodiment, which includes the state acquisition device 27 to enable the controller 11 to directly acquire information about a state in the loading platform 71, the second embodiment includes a controller 11 which serves as an estimation means for estimating a state in the loading platform 71, instead of the state acquisition device 27. The controller 11 further performs the selection of a release motion from a plurality of candidate motions based on the state in the loading platform 71, which state is estimated by the controller 11 itself.

In the example shown in FIGS. 24 and 25, soil and sand E1 is loaded into the front side portion (left side portion in the drawing) of the loading platform 71 by the first release motion, and soil and sand E2 is loaded into the intermediate portion of the loading platform 71 by the second release motion. This leaves a space 79 into which soil and sand is to be loaded on the rear side portion (right side portion in the drawing) of the loading platform 71 by the third release motion. Regarding this state, the information that each of the first and second release motions is the first candidate motion M1 that has been described as to the first embodiment, namely, past working results, enables it to be analogized that the planar area of the space 79 in which soil and sand is to be loaded by the third release motion is smaller than the area Aa corresponding to the first candidate motion Ma and equal to or greater than the area Ab corresponding to the second candidate motion Mb.

The controller 11 serves as a number-of-times setting means for setting a target number of times. The target number of times is the target value of the number of times of repetition of the holding motion and the release motion. The target number of times is set by, for example, an instruction from the mobile terminal 90 shown in FIG. 2. In the case of the example shown in FIGS. 24 and 25, the target number of times is three times. The controller 11 estimates a state in the loading platform 71 based on comparison of the number of times the holding motion and the release motion have been repeated at the present time and the target number of times set in advance as described above. For example, in the case where the holding motion and the release motion have been repeated twice at the present time, the next release motion is the third time; hence, when the first candidate motion Ma is performed as the first and second release motions, the planar area of the space 79 into which the soil and sand is to be loaded by the third release motion is estimated from the area Aa corresponding to the first candidate motion Ma. Specifically, the area of the space 79 to be estimated is smaller than the area Aa corresponding to the first candidate motion Ma and equal to or greater than the area Ab corresponding to the second candidate motion Mb. Based on the thus estimated area, the controller 11 selects the second candidate motion Mb as the third release motion, and makes the loading of soil and sand into the space 79 performed by the second candidate motion Mb. This enables soil and sand to be loaded into the space 79 with reduced unevenness.

Thus using the past work results enables the state of loading of the soil and sand in the loading platform 71 to be suitably estimated from the number of times the holding motion and the release motion have been repeated. The estimation of state allows the release motion to be suitably selected from the plurality of candidate motions without using any device capable of directly acquiring the state in the loading platform 71.

The controller 11 may serve as a mass setting means for setting a target mass in place of the target number of times. The target mass is the target value of the mass of soil and sand to be loaded in the loading platform 71. For example, the target mass is set by an instruction from the mobile terminal 90 shown in FIG. 2. On the other hand, the work machine 101 according to the present embodiment has a known payload function. The payload function is a function of measuring a load by soil and sand and the like held in the bucket 33, that is, a load acting on the bucket 33 due to the gravity of soil and sand. Based on the load thus acting on the bucket 33 and the number of times the release motion has been performed, the mass of the soil and sand having been loaded into the loading platform 71 at the present time can be determined.

The controller 11 serves as an estimation means for estimating a state in the loading platform 71 based on the mass of soil and sand having been loaded in the loading platform 71 at the present time and the target mass. For example, the state where the difference between the mass of soil and sand having been loaded in the loading platform 71 at the present time and the target mass is equal to the mass of soil and sand holdable in a single bucket teaches that the next release motion is the final release motion (the third release motion in the present embodiment). Moreover, based on the type of the first and second release motions, that is, the candidate motion that is selected as the release motion, the planar area of the space 79 into which soil and sand is to be loaded by the third release motion can be estimated. For example, when each of the first and second release motions is the first candidate motion Ma, the area of the space 79 to be estimated is smaller than the area Aa corresponding to the first candidate motion Ma and equal to or greater than the area Ab corresponding to the second candidate motion Mb. Accordingly, the controller 11 selects the second candidate motion Mb as the third release motion and makes the loading of soil and sand into the space 79 performed by the second candidate motion Mb. This enables soil and sand to be loaded into the space 79 with reduced unevenness.

Thus using the past work results enables the state of the soil and sand in the loading platform 71 to be suitably estimated from the mass of the soil and sand having been loaded into the loading platform 71.

It is also possible to determine the mass of soil and sand having been loaded in the loading platform 71 at the present time based on the load acting on the loading platform 71 of the dump truck 70. This can be achieved, for example, through communication between the dump truck 70 and the work machine 101.

The controller 11 may serve as a volume setting means for setting a target volume in place of the target number of times or the target mass. The target volume is the target value of the volume of soil and sand to be loaded in the loading platform 71. For example, the target volume is set by an instruction from the mobile terminal 90 shown in FIG. 2. The storage device 13 stores the volume of the bucket 33. Based on the volume of the bucket 33 and the number of times the release motion has been performed, the volume of the soil and sand having been loaded into the loading platform 71 at the present time can be determined.

In this case, the controller 11 also serves as an estimation means for estimating a state in the loading platform 71 based on the volume of soil and sand having been loaded in the loading platform 71 at the present time and the target volume set in advance as described above. For example, the state where the difference between the volume of soil and sand having been loaded in the loading platform 71 at the present time and the target volume is equal to the volume of soil and sand holdable in a single bucket teaches that the next release motion is the final release motion (the third release motion in the embodiment). Moreover, based on the type of the first and second release motions, that is, the candidate motion that is selected as the release motion, the planar area of the space 79 into which the soil and sand is to be loaded by the third release motion can be estimated. For example, when each of the first and second release motions is the first candidate motion Ma, the area of the space 79 to be estimated is smaller than the area Aa corresponding to the first candidate motion Ma and equal to or greater than the area Ab corresponding to the second candidate motion Mb. Accordingly, the controller 11 selects the second candidate motion Mb as the type of the third release motion, and makes the loading of soil and sand into the space 79 performed by the second candidate motion Mb. This enables soil and sand to be loaded into the space 79 with reduced unevenness.

Thus using the past work results enables the state of the soil and sand in the loading platform 71 to be suitably estimated from the volume of the soil and sand having been loaded into the loading platform 71 at the present time.

The work machine 101 according to the present embodiment, if including a sensor capable of imaging the soil and sand in the loading platform 71, such as a LiDAR, a TOF sensor or a stereo camera, allows the volume of soil and sand having been loaded in the loading platform 71 at the present time to be determined based on the soil and sand in the loading platform 71 captured by the sensor.

Besides, as shown in FIG. 26, the controller 11 may be configured to estimate a state in the loading platform 71 based on a release position at which the next release motion is to be performed in the loading platform 71. In the example shown in FIG. 26, a vertically extending boundary surface 80 is set on the loading platform 71, and the position of the boundary surface 80 is set so as to render the planar area of the space of a front-side portion (left side portion in drawing) Rf, which is a portion on the front side of the boundary surface 80 in the loading platform 71, larger than the area Aa corresponding to the first candidate motion Ma, and so as to render the planar area of the space of the rear side portion (right side portion in drawing) Rr, which is a portion on the rear side of the boundary surface 80, smaller than the area Aa and equal to or greater than the area Ab corresponding to the second candidate motion Mb. The controller 11 can perform suitable selection of the release motion based on the relative relationship of the release position to the boundary surface 80. Specifically, when the next release position is on the front side of the boundary surface 80 with respect to the front-rear direction of the loading platform 71, the controller 11 selects the first candidate motion Ma as the next release motion. In contrast, when the next release position is on the rear side of the boundary surface 80 with respect to the front-rear direction of the loading platform 71, the controller 11 selects the second candidate motion Mb as the next release motion. This enables soil and sand to be loaded into the portion on the rear side portion of the boundary surface 80 in the loading platform 71 with reduced unevenness.

As has been described, according to the work machine 101 according to the present embodiment, the estimation of the state in the loading platform 71 enables the selection of the release motion to be suitably performed without using any device capable of directly acquiring the state in the loading platform 71.

Specifically, in the example shown in FIGS. 24 and 25, the state in the loading platform 71 is estimated based on the number of times the holding motion and the release motion have been repeated at the present time and the target number of times. For example, by use of the past work results, the state in the loading platform 71 can be suitably estimated from the number of times the holding motion and the release motion have been repeated at the present time.

Besides, in the other examples shown in FIGS. 24 and 25, the state in the loading platform 71 is estimated based on the mass of the soil and sand having been loaded in the loading platform 71 at the present time and the target mass. For example, by use of the past work results, the state in the loading platform 71 can be suitably estimated from the mass of soil and sand having been loaded in the loading platform 71 at the present time.

Besides, in the other examples shown in FIGS. 24 and 25, the state in the loading platform 71 is estimated based on the volume of the soil and sand having been loaded into the loading platform 71 at the present time and target volume. For example, by use of the past work results, the state in the loading platform 71 can be suitably estimated from the volume of soil and sand having been loaded into the loading platform 71 at the present time.

In the example shown in FIG. 26, the state in the loading platform 71 is estimated based on the position at which the next release motion is performed in the loading platform 71, namely, the release position. For example, the state where the next release position is in the end of the loading platform 71 allows it to be estimated that the planar area of the space in the end of the loading platform 71 is small. This causes a candidate motion by which the planar area of the soil and sand loaded into the loading platform 71 is small to be selected as the release motion from among the plurality of candidate motions. This enables soil and sand to be loaded into a small space at the end of the loading platform 71 with reduced unevenness.

The embodiments of the present invention that have been described are not more than examples of specific examples, having no intention to particularly limiting the present invention. The specific configuration or the like can be designed and changed as appropriate. The actions and effects described in the embodiments of the invention are merely listing most suitable actions and effects arising from the present invention, and the actions and effects of the invention are not limited to those described in the embodiments of the present invention.

As has been described, provided is a work machine capable of loading a loading object into a container with reduced unevenness. The work machine includes a machine body, an attachment and a controller. The attachment includes a bucket capable of holding a loading object, attached to the machine body. The controller automatically makes the attachment repeat a holding motion and a release motion alternately. The holding motion is a motion of holding the loading object in the bucket. The release motion is a motion of releasing the loading object held in the bucket into the container. The release motion is selected from among a plurality of candidate motions, which are different from each other in a planar area, which is an area in plan view, of the loading object to be released into the container by each candidate motion and spread in the container. The controller is configured to select the release motion from the plurality of candidate motions in accordance with a state in the container.

The controller can select the area of the loading object to be loaded into the container by the release motion, by the selection of the release motion from among the plurality of candidate motions in accordance with the state in the container. For example, when the planar area of the empty space in the container is acquired as information about the state in the container, the controller selects, as the release motion, a candidate motion by which the planar area of the loading object to be loaded into the container is small, from among the plurality of candidate motions, when the planar arca of the empty space is small, thereby allowing the loading object to be loaded into the empty space in the container with reduced unevenness. Thus selecting the candidate motion suitable for the state in the container from among the plurality of candidate motions as the release motion enables loading objects to be loaded into the entire container with reduced unevenness.

The plurality of candidate motions preferably include a motion of releasing the loading object while fixing a relative position of a part of the bucket to the machine body in the longitudinal direction of the attachment.

The plurality of candidate motions preferably include a motion of releasing the loading object while moving the bucket in the longitudinal direction of the attachment with respect to the container.

Preferably, the work machine further includes a state acquisition device that acquires information about a state in the container and the controller is configured to select the release motion from the plurality of candidate motions based on the information acquired by the state acquisition device.

For example, the state acquisition device acquires, as information about the state in the container, a planar area of a space into which the loading object is to be released by the next release motion in the container.

The state acquisition device, alternatively, may acquire the shape of the loading object having been loaded in the container as information about the state in the container. In this case, it is preferable that the controller is configured to select the release motion from the plurality of candidate motions based on comparison of the shape of the loading object acquired by the state acquisition device with a preset target shape.

The controller, alternatively, may be configured to estimate a state in the container and to select the release motion from the plurality of candidate motions based on the estimated state in the container.

Specifically, the controller may be configured to estimate a state in the container based on either of comparison of the number of times the holding motion and the release motion have been repeated with a preset target number of times, comparison of the mass of the loading object having been loaded into the container with a preset target mass, comparison of the volume of the loading object having been loaded in the container with a preset target volume, and a position at which the next release motion is to be performed in the container.

Claims

1. A work machine comprising:

a machine body;

an attachment attached to the machine body, the attachment including a bucket capable of holding a product; and

a controller that automatically makes the attachment alternately repeat a holding motion of holding a loading object in the bucket and a release motion of releasing the loading object held in the bucket into a container, wherein:

the release motion is selected from among a plurality of candidate motions, which are different from each other in a planar area, which is an area in plan view, of the loading object to be loaded into the container by each candidate motion and spread in the container; and

the controller is configured to select the release motion from the plurality of candidate motions in accordance with a state in the container.

2. The work machine according to claim 1, wherein the plurality of candidate motions include a motion of releasing the loading object while fixing a relative position of a part of the bucket to the machine body in a longitudinal direction of the attachment.

3. The work machine according to claim 1, wherein the plurality of candidate motions include a motion of releasing the loading object while moving the bucket in the longitudinal direction of the attachment with respect to the container.

4. The work machine according to claim 1, further comprising a state acquisition device that acquires information about a state in the container, wherein the controller is configured to select the release motion from the plurality of candidate motions based on the information acquired by the state acquisition device.

5. The work machine according to claim 4, wherein the state acquisition device acquires, as the information about the state in the container, a planar area of a space into which the loading object is to be loaded by the next release motion in the container.

6. The work machine according to claim 4, wherein the state acquisition device acquires a shape of the loading object having been loaded into the container as the information about the state in the container, and the controller is configured to select the release motion from the plurality of candidate motions based on comparison of the shape of the loading object acquired by the state acquisition device with a preset target shape.

7. The work machine according to claim 1, wherein the controller is configured to estimate a state in the container and to select the release motion from the plurality of candidate motions based on the estimated state in the container.

8. The work machine according to claim 7, wherein the controller is configured to estimate a state in the container based on comparison of the number of times the holding motion and the release motion have been repeated and a preset target number of times.

9. The work machine according to claim 7, wherein the controller is configured to estimate a state in the container based on comparison of a mass of the loading object having been loaded into the container with a preset target mass.

10. The work machine according to claim 7, wherein the controller is configured to estimate a state in the container based on comparison of a volume of the loading object having been loaded in the container with a preset target volume.

11. The work machine according to claim 7, wherein the controller is configured to estimate a state in the container based on a position at which the next release motion is performed in the container.