Navigation system and method for machine

Patent metadata

Field	Value
Publication number	US-9341683-B2
Application number	US-201414499613-A
Country	US
Kind code	B2
Filing date	Sep 29, 2014
Priority date	Sep 29, 2014
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

A method of determining a heading of a machine having an implement is provided. The method includes determining a first heading data of the machine using an inertial sensor. The method includes determining a second heading data of the machine using a magnetometer. The method includes determining a position of the implement in a stationary state. The method also includes calculating a corrected second heading data based on a predefined relation between the position of the implement in the stationary state and the second heading data. The method further includes determining the heading of the machine based on the first heading data and the corrected second heading data.

First claim

What is claimed is:

1. A method of determining a heading of a machine having a frame and a work implement to perform work on a worksite, the work implement attached to the frame through a linkage, and moveable in respect to the frame through the linkage, the method comprising:
determining with an implement module that the work implement is in one of a moving state and a stationary state;
determining a position of the work implement in relation to the frame with the implement module;
determining a first heading data of the machine using an inertial sensor;
determining a second heading data of the machine using a magnetometer;
calculating a corrected second heading data based on a predefined relation between the position of the work implement in relation to the frame and the second heading data, when the work implement is in a stationary state; and
determining the heading of the machine based on the first heading data and the corrected second heading data, when the work implement is in the stationary state.

2. The method of claim 1 , wherein the predefined relation between the position of the work implement when the work implement is in the stationary state and the second heading data comprises a lookup table.

3. The method of claim 1 further comprising
determining the heading of the machine based on the first heading data when the work implement is in the moving state.

4. The method of claim 1 , wherein the inertial sensor is a gyroscopic sensor.

5. The method of claim 1 further comprising:
receiving a position data from a global positioning system associated with the machine; and
determining the heading of the machine based on the first heading data, the corrected second heading data and the position data of the machine, when the work implement is in the stationary state.

6. The method of claim 1 , wherein the machine is a hydraulic excavator, and the linkage includes an arm and a pivot.

7. The method of claim 1 , wherein the work implement is a bucket.

8. A navigation system of a machine, the machine including a frame and a work implement for performing work on a worksite, the work implement attached to the frame through a linkage, and moveable in respect to the frame through the linkage, the navigation system comprising:
an inertial sensor configured to provide a first heading data of the machine;
a magnetometer configured to provide a second heading data of the machine; and
an implement module configured to determine the work implement is in one of a stationary state and a moving state, and to determine a position of the implement when the work implement is in a stationary state; and
wherein the navigation system is configured to:
calculate a corrected second heading data based on a predefined relation between the position of the work implement and the second heading data when the work implement is in the stationary state; and
determine a heading of the machine based on the first heading data and the corrected second heading data when the work implement is in the stationary state.

9. The navigation system of claim 8 , wherein the predefined relation between the position of the work implement in the stationary state and the second heading data comprises a lookup table.

10. The navigation system of claim 8 being further configured to
determine the heading of the machine based on the first heading data when the work implement is in the moving state.

11. The navigation system of claim 8 , wherein the inertial sensor is a gyroscopic sensor.

12. The navigation system of claim 8 being further configured to:
receive a position data from a global positioning system associated with the machine; and
determine the heading of the machine based on the first heading data, the corrected second heading data and the position data of the machine.

13. The system of claim 8 , wherein the machine is a wheel loader.

14. The system of claim 8 , wherein the linkage moves the work implement in respect to the frame with at least one hydraulic cylinder, and the implement module determines that the work implement is in one of a stationary state and a moving state, at least in part, in response to a pressure signal from a pressure sensor for measuring pressure in the at least one hydraulic cylinder.

15. A machine comprising:
a frame;
a work implement for performing work at a worksite, the work implement attached to the frame through a linkage, and movable with respect to the frame through the linkage; and
a navigation system associated with the machine, the navigation system comprising:
an inertial sensor configured to detect a first heading data of the machine;
a magnetometer configured to detect a second heading data of the machine; and
an implement module operatively coupled to the work implement and configured to determine that the work implement is in one of a stationary state and a moving state, and a position of the work implement when the work implement is in the stationary state; and

wherein the navigation system is configured to:
calculate a corrected second heading data based on a predefined relation between the position of the work implement and the second heading data, when the work implement is in the stationary state; and
determine a heading of the machine based on the first heading data and the corrected second heading data when the work implement is in the stationary state.

16. The machine of claim 15 , wherein the predefined relation between the position of the work implement and the second heading data when the work implement is in the stationary state comprises a lookup table.

17. The machine of claim 15 , wherein the navigation system is further configured to
determine the heading of the machine based on the first heading data when the work implement is in the moving state.

18. The machine of claim 15 , wherein the inertial sensor is a gyroscopic sensor.

19. The machine of claim 15 , wherein the machine is a hydraulic excavator.

20. The machine of claim 15 , wherein the work implement is a bucket.

Assignees

• Caterpillar Inc

Inventors

• Friend Paul R
• Willis Frank A

Classifications

• G01C21/188

  for accumulated errors, e.g. by coupling inertial systems with absolute positioning systems · CPC title

• G01C21/1654

  with electromagnetic compass · CPC title

• G01R33/02

  Measuring direction or magnitude of magnetic fields or magnetic flux (G01R33/20 takes precedence) · CPC title

• G01R33/025 Primary

  Compensating stray fields {(G01R33/0017 takes precedence)} · CPC title

• G01C21/165

  combined with non-inertial navigation instruments · CPC title