# US 11,906,641 B2 · Work machine

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- Number: US 11,906,641 B2
- Document ID: US11906641B2
- Status: Granted
- Kind: B2
- Application number: 17/274,923
- Filed: 2019-06-06
- Published: 2022-01-27
- Granted: 2024-02-20
- Earliest claimed: 2018-09-21
- Assignees: Hitachi Construction Machinery Co., Ltd.
- Applicants: Hitachi Construction Machinery Co., Ltd.
- Inventors: Naoki Hayakawa; Shiho Izumi
- Web page: https://patentgrep.com/patent/US11906641B2

## CPC

- E02F 9/265: {with follow-up actions (e.g. control signals sent to actuate the work tool)}
- G01S 19/485: {whereby the further system is an optical system or imaging system}
- E02F 3/437: {providing automatic sequences of movements, e.g. linear excavation, keeping dipper angle constant}
- E02F 3/841: {Devices for controlling and guiding the whole machine, e.g. by feeler elements and reference lines placed exteriorly of the machine (construction of roads E01C19/008)}
- E02F 9/2045: {Guiding machines along a predetermined path (for graders E02F3/841; machines for construction of roads E01C19/004)}
- G01C 11/04: Interpretation of pictures
- G01C 15/06: Surveyors' staffs; Movable markers
- G01C 21/20: Instruments for performing navigational calculations (G01C21/24, G01C21/26 take precedence)
- G01S 19/48: by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system
- G01S 19/51: Relative positioning
- E02F 3/32: working downwardly and towards the machine, e.g. with backhoes
- E02F 3/435: {for dipper-arms, backhoes or the like}
- E02F 9/262: {with follow-up actions to control the work tool, e.g. controller}
- E02F 9/264: {Sensors and their calibration for indicating the position of the work tool}
- G01S 19/40: Correcting position, velocity or attitude
- E02F: DREDGING; SOIL-SHIFTING (winning peat E21C49/00)
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S)

## Abstract

A coordinate conversion system including a controller that converts geographic-coordinate-system coordinates of a certain point into site-coordinate-system coordinates includes: an image-capturing device that captures an image of a reference point; and a GNSS antenna that receives a navigation signal. The controller calculates geographic-coordinate-system coordinates of the image-capturing device on the basis of the navigation signal received at the GNSS antenna, and a distance between the image-capturing device and the GNSS antenna; calculates a distance and direction from the image-capturing device to the reference point by performing image processing on the image of the reference point captured by the image-capturing device; calculates the geographic-coordinate-system coordinates of the reference point on the basis of the calculated distance and direction from the image-capturing device to the reference point, and the calculated geographic-coordinate-system coordinates of the image-capturing device; and calibrates the coordinate conversion parameter on the basis of the calculated geographic-coordinate-system coordinates of the reference point, and the site-coordinate-system coordinates of the reference point.

## Claims

### Claim 1

A work machine including a controller that is configured to convert geographic-coordinate-system coordinates of a certain point into site-coordinate-system coordinates by using a coordinate conversion parameter generated on a basis of geographic-coordinate-system coordinates and site-coordinate-system coordinates of a reference point installed at a work site, the work machine comprising:
a machine body;
a work implement that is attached to the machine body, and is driven by a hydraulic cylinder;
an image-capturing device that captures an image of the reference point;
a GNSS antenna that is attached to the machine body, and receives a navigation signal; and
a posture sensor that detects a posture of the work implement, wherein
the controller is configured to
calculate geographic-coordinate-system coordinates of the image-capturing device on a basis of the navigation signal received at the GNSS antenna, and a distance between the image-capturing device and the GNSS antenna,
calculate a distance and direction from the image-capturing device to the reference point by performing image processing on the image of the reference point captured by the image-capturing device,
calculate the geographic-coordinate-system coordinates of the reference point on a basis of the calculated distance and direction from the image-capturing device to the reference point, and the calculated geographic-coordinate-system coordinates of the image-capturing device,
calibrate the coordinate conversion parameter on a basis of the calculated geographic-coordinate-system coordinates of the reference point, and the site-coordinate-system coordinates of the reference point,
calculate geographic-coordinate-system coordinates of the machine body on a basis of the navigation signal received at the GNSS antenna,
calculate geographic-coordinate-system coordinates of a control point set for the work implement on a basis of the geographic-coordinate-system coordinates of the machine body, and information about the posture of the work machine detected by the posture sensor,
convert the geographic-coordinate-system coordinates of the control point into site-coordinate-system coordinates by using the coordinate conversion parameter calibrated by the controller, and
perform control on a basis of the converted site-coordinate-system coordinates.

### Claim 2 (depends on 1)

The work machine according to claim 1, wherein
information about the site-coordinate-system coordinates of the reference point is embedded in a marker installed at the reference point,
the image-capturing device captures an image of the marker along with the image of the reference point, and
the controller acquires the site-coordinate-system coordinates of the reference point on a basis of the image of the reference point and the image of the marker captured by the image-capturing device.

### Claim 3 (depends on 1)

The work machine according to claim 1, wherein
the controller associates the geographic-coordinate-system coordinates of the reference point calculated by the controller with identification information of the reference point, and outputs the associated geographic-coordinate-system coordinates and identification information to a server connected to the controller via a network.

### Claim 4 (depends on 1)

The work machine according to claim 1, wherein
the controller is configured to perform coordinate conversion by using the calibrated coordinate conversion parameter when the coordinate conversion parameter is calibrated by the controller.

### Claim 5 (depends on 1)

The work machine according to claim 1, wherein
the image-capturing device is pivotable in an upward/downward direction, and a leftward/rightward direction, and
the controller controls a direction of the image-capturing device such that the reference point is always included in an image-capturing range of the image-capturing device.

### Claim 6 (depends on 1)

The work machine according to claim 1, wherein the controller causes a positional relation between the control point and a predetermined target surface in the converted site-coordinate-system coordinates to be displayed on a monitor.

### Claim 7 (depends on 6)

The work machine according to claim 6, wherein
the controller controls the hydraulic cylinder such that the work implement is positioned above the target surface.

### Claim 8 (depends on 6)

The work machine according to claim 6, wherein
the controller associates the geographic-coordinate-system coordinates of the reference point calculated by the controller with identification information of the reference point, and outputs the associated geographic-coordinate-system coordinates and identification information to a server connected to the controller via a network.

### Claim 9 (depends on 8)

The work machine according to claim 8, wherein
the controller receives the calibrated coordinate conversion parameter, and is configured to perform coordinate conversion of the control point by using the received coordinate conversion parameter when the controller is notified that the coordinate conversion parameter has been calibrated from the server that calibrates the coordinate conversion parameter on a basis of the geographic-coordinate-system coordinates and the site-coordinate-system coordinates of the reference point when the geographic-coordinate-system coordinates of the reference point have been updated.

### Claim 10 (depends on 1)

The work machine according to claim 1, wherein
the controller is configured to repeatedly execute, at a predetermined cycle, a calibration process of the coordinate conversion parameter based on the calculated geographic-coordinate-system coordinates of the reference point, and the stored and identified site-coordinate-system coordinates of the reference point.