BACKUP VELOCITY ESTIMATION UTILIZING TRACTION DEVICE SPEED

• US 20140039748A1
• Filed: 08/01/2012
• Published: 02/06/2014
• Est. Priority Date: 08/01/2012
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: FRIEND, Paul Russell, Fehr, Drew Alan
• Granted Patent: US 9,052,391 B2
• Time in Patent Office: Days
• US Class Current: 701/29.7
• CPC Class Codes: G01C 21/04 by terrestrial means G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01C 21/165 combined with non-inertial navigation instruments
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments
• CPC Class Codes: G01P 3/50 for measuring linear speed G01P3/56 takes precedence
• CPC Class Codes: G01S 19/26 involving a sensor measurement for aiding acquisition or tracking
• CPC Class Codes: G01S 19/52 Determining velocity
• CPC Class Codes: G06F 11/30 Monitoring

Abstract

A velocity estimation method and system is disclosed. The method may include receiving a location signal indicative of a location of the machine and estimating the velocity of the machine based on a change in the location of the machine over a period of time. The method may further include determining a loss of the location signal, detecting a traction device speed of the machine, and selectively estimating the velocity of the machine based on the traction device speed when the location signal is determined to be lost.

Claims

1. A method of estimating velocity of a machine, comprising:

receiving a location signal indicative of a location of the machine;

estimating the velocity of the machine based on a change in the location of the machine over a period of time;

determining a loss of the location signal;

detecting a traction device speed of the machine; and

selectively estimating the velocity of the machine based on the traction device speed when the location signal is determined to be lost.

2. The method of claim 1, wherein the location signal is a GPS signal.

3. The method of claim 1, wherein the traction device speed is a track speed of the machine.

4. The method of claim 1, further including:

detecting an acceleration of the machine;

determining a reliability of the traction device speed; and

selectively estimating the velocity of the machine based on the detected acceleration when the traction device speed is determined to be unreliable.

5. The method of claim 4, further including:

detecting steering of the machine; and

determining that the traction device speed is unreliable when the detected steering exceeds a predetermined threshold.

6. The method of claim 1, wherein the velocity of the machine is calculated using a Kalman filter.

7. The method of claim 6, further including:

detecting a measurement variance for the traction device speed; and

utilizing the measurement variance as an input to the Kalman filter to estimate the velocity of the machine.

8. The method of claim 1, wherein the velocity of the machine is selectively estimated based on the traction device speed and a detected traction device speed slip.

9. A velocity estimation system for a machine, comprising:

a locating device configured to generate a first signal indicative of a location of the machine;

a sensor configured to generate a second signal indicative of a traction device speed of the machine; and

a controller in communication with the locating device and the sensor, the controller configured to;

receive the first signal from the locating device and the second signal from the sensor;

estimate the velocity of the machine based on a change in the location of the machine over a period of time;

determine a loss of the first signal;

detect a traction device speed of the machine based on the received second signal; and

selectively estimate the velocity of the machine based on the detected traction device speed when the first signal is determined to be lost.

10. The velocity estimation system of claim 9, wherein the first signal is a GPS signal.

11. The velocity estimation system of claim 9, wherein the traction device speed is a track speed of the machine.

12. The velocity estimation system of claim 9, further including:

a forward acceleration sensor configured to detect an acceleration of the machine,

wherein the controller is further configured to;

determine a reliability of the traction device speed; and

selectively estimate the velocity of the machine based on the detected acceleration when the traction device speed is determined to be unreliable.

13. The velocity estimation system of claim 12, further including:

a turning detecting unit configured to detect steering of the machine,

wherein the controller is further configured to;

determine that the traction device speed is unreliable when the detected steering exceeds a predetermined threshold.

14. The velocity estimation system of claim 9, wherein the velocity of the machine is calculated using a Kalman filter.

15. The velocity estimation system of claim 14, wherein the controller is further configured to:

detect a measurement variance for the traction device speed; and

utilize the measurement variance as an input to the Kalman filter to estimate the velocity of the machine.

16. The velocity estimation system of claim 9, wherein the velocity of the machine is selectively estimated based on the traction device speed and a detected traction device speed slip.

17. A non-transitory computer-readable storage medium storing instructions for estimating velocity of a machine, the instructions causing one or more computer processors to perform operations comprising:

receiving a location signal indicative of a location of the machine;

estimating the velocity of the machine based on a change in the location of the machine over a period of time;

determining a loss of the location signal;

detecting a traction device speed of the machine; and

selectively estimating the velocity of the machine based on the traction device speed when the location signal is determined to be lost.

18. The non-transitory computer-readable storage medium of claim 17, wherein the location signal is a GPS signal and the traction device speed is a track speed of the machine.

19. The non-transitory computer-readable storage medium of claim 17, wherein the operations further include:

detecting an acceleration of the machine;

determining a reliability of the traction device speed; and

selectively estimating the velocity of the machine based on the detected acceleration when the traction device speed is determined to be unreliable.

20. The non-transitory computer-readable storage medium of claim 19, wherein the operations further include:

detecting steering of the machine; and

determining that the traction device speed is unreliable when the detected steering exceeds a predetermined threshold.

21. The non-transitory computer-readable storage medium of claim 17, wherein the velocity of the machine is calculated using a Kalman filter.

22. The non-transitory computer-readable storage medium of claim 21, wherein the operations further include:

detecting a measurement variance for the traction device speed; and

utilizing the measurement variance as an input to the Kalman filter to estimate the velocity of the machine.

23. The non-transitory computer-readable storage medium of claim 17, wherein velocity of the machine is selectively estimated based on the traction device speed and a detected traction device speed slip.