Work machine

Patent metadata

Field	Value
Publication number	US-12146291-B2
Application number	US-202117639921-A
Country	US
Kind code	B2
Filing date	Mar 5, 2021
Priority date	Mar 24, 2020
Publication date	Nov 19, 2024
Grant date	Nov 19, 2024

Abstract

A controller determines whether or not a work device is in a ground contact state, by using detection data of a pressure sensor and at least one balance relation between forces or moments acting on the work device, and generate partial shape data of a work object formed by the work device, on the basis of a movement locus of a monitoring point set to the work device and an external shape of the work device in a ground contact period in which the work device is determined to be in the ground contact state, and update the present-condition shape data of the work object on the basis of the partial shape data.

First claim

The invention claimed is:

1. A work machine comprising:
a machine body;
a work device attached to the machine body, the work device having an attachment at a distal end thereof;
a machine body position computing device configured to compute a position of the machine body;
a posture sensor that detects a posture of the work device;
a pressure sensor that detects driving states of a plurality of hydraulic actuators that drive the work device; and
a controller configured to compute position information of a monitoring point set to the attachment, on a basis of the position of the machine body, the machine body position being computed by the machine body position computing device, and a position of the work device, the work device position being computed from detection data of the posture sensor, and update present-condition shape data of a work object of the work device by using the position information;
the controller being configured to
determine whether or not the attachment is in a ground contact state, by using detection data of the pressure sensor and at least one balance relation between forces or moments acting on the work device, and
generate partial shape data of the work object formed by the attachment, on a basis of a movement locus of the monitoring point set to the attachment and an external shape of the attachment in a ground contact period in which the attachment is determined to be in the ground contact state, and update the present-condition shape data of the work object on a basis of the partial shape data.

2. The work machine according to claim 1 , wherein
a plurality of the monitoring points are set to the attachment, and
the external shape is defined by positions of the plurality of monitoring points.

3. The work machine according to claim 2 , wherein
the controller is configured to
generate the partial shape data on a basis of a first external shape defined by the positions of the plurality of monitoring points at a first time in the ground contact period in which the attachment is determined to be in the ground contact state, a second external shape defined by the positions of the plurality of monitoring points at a second time later than the first time in the ground contact period, and movement loci of the plurality of monitoring points in a period from the first time to the second time.

4. The work machine according to claim 2 , further comprising:
an operation lever for operating the work device, wherein
the controller stores a target surface on which a target shape of a construction object of the work device is defined,
the controller is configured to
make a determination of an operation of the work device on a basis of data including an operation amount input to the operation lever and a target surface distance as a distance from the attachment to the target surface, and decide a ground contact region in which the attachment is estimated to be in contact with a ground from a result of the operation determination, and
the movement locus is a movement locus of a monitoring point belonging to the ground contact region among the plurality of monitoring points set to the attachment.

5. The work machine according to claim 4 , wherein
the attachment is a bucket,
the plurality of monitoring points are a plurality of points set to the bucket, and the plurality of points include a first point set to a claw tip of the bucket and a second point set to a rear end of a bottom surface of the bucket, and
the controller is configured to
select a first ground contact region including the first point as the ground contact region when the result of the operation determination is an excavating operation,
select a second ground contact region including the second point as the ground contact region when the result of the operation determination is a tamping operation, and
select a third ground contact region including the first point and the second point as the ground contact region when the result of the operation determination is a bumping operation.

6. The work machine according to claim 5 , wherein
the controller is configured to
generate the partial shape data on a basis of the movement locus when the result of the operation determination is the excavating operation,
generate the partial shape data on a basis of the movement locus when the result of the operation determination is the tamping operation, and
generate the partial shape data on a basis of the external shape defined by positions of the plurality of points in the ground contact period in which the work device is determined to be in the ground contact state, when the result of the operation determination is the bumping operation.

7. The work machine according to claim 3 , wherein
the controller is configured to divide a work device passage region as a region enclosed by the first external shape, the second external shape, and the movement loci into a plurality of sections in a horizontal direction, and generate the partial shape data on a basis of a line segment located on a lower side in a gravitational direction in each of the sections having been divided.

8. The work machine according to claim 3 , wherein
the attachment is a bucket,
the plurality of monitoring points are a plurality of points set to the bucket, and
the controller is configured to divide a work device passage region as a region enclosed by the first external shape, the second external shape, and the movement loci into a plurality of sections by a plurality of radial straight lines passing through a center of rotation of the bucket, and generate the partial shape data on a basis of a line segment farthest from the center of rotation of the bucket in each of the sections having been divided.

9. The work machine according to claim 3 , wherein
the controller stores a target surface on which a target shape of a construction object of the work device is defined, and
the controller is configured to divide a work device passage region as a region enclosed by the first external shape, the second external shape, and the movement loci into a plurality of sections in a direction along the target surface, and generate the partial shape data on a basis of a line segment closest to the target surface in each of the sections having been divided.

10. The work machine according to claim 3 , wherein
the controller is configured to divide a work device passage region as a region enclosed by the first external shape, the second external shape, and the movement loci into a plurality of sections in a direction along a present-condition shape defined by the present-condition shape data, and generate the partial shape data on a basis of a line segment located below the present-condition shape and farthest from the present-condition shape in each of the sections having been divided.

11. The work machine according to claim 1 , wherein
the controller is configured to generate progress state data of work by the work device by using the present-condition shape data updated on a basis of the partial shape data, and
the work machine further includes a monitor that displays the progress state data generated by the controller.

Assignees

• Hitachi Construction Mach Co

Inventors

• Hayakawa Naoki
• Izumi Shiho

Classifications

• E02F9/2029

  Controlling the position of implements in function of its load, e.g. modifying the attitude of implements in accordance to vehicle speed (control for hydraulic or pneumatic drives E02F9/2203, E02F9/2221 and E02F9/2253 take precedence) · CPC title

• B60Y2200/412

  Excavators · CPC title

• G05B13/04

  involving the use of models or simulators · CPC title

• E02F9/2004

  Control mechanisms, e.g. control levers (control levers per se G05G) · CPC title

• E02F9/26

  Indicating devices {(E02F5/145 takes precedence)} · CPC title