Backup velocity estimation utilizing traction device speed

• US 9,052,391 B2
• Filed: 08/01/2012
• Issued: 06/09/2015
• Est. Priority Date: 08/01/2012
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Friend, Paul Russell, Fehr, Drew Alan
• Primary Examiner(s): Jabr, Fadey
• Assistant Examiner(s): INGRAM, THOMAS P
• Application Number:
  US13/564,603
• Publication Number:
  US 20140039748A1
• Time in Patent Office: 1,042 Days
• Field of Search: 701/468, 701/472, 701/480, 701/500
• US Class Current: 1/1
• 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, from a locating device, a location signal indicative of a location of the machine;

estimating, by a processor, the velocity of the machine based on a change in the location of the machine indicated by the received location signal over a period of time;

determining, by the processor, a loss of the location signal;

detecting, by the processor, a traction device speed of the machine;

detecting, by the processor, an acceleration of the machine;

detecting, by the processor, steering of the machine;

determining, by the processor, whether the traction device speed is unreliable, wherein the traction device speed is determined as unreliable when the detected steering exceeds a predetermined threshold; and

when the location signal is determined to be lost and the traction device speed is determined to be unreliable, estimating, by the processor, the velocity of the machine based on the detected acceleration.

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:

when the location signal is determined to be lost and the traction device speed is determined as not unreliable, estimating the velocity of the machine based on a detected traction device speed slip.

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

6. The method of claim 5, further including:

detecting, by the processor, a measurement variance for the traction device speed; and

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

7. 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 indicated by the first signal 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;

detect an acceleration of the machine;

detect a steering of the machine;

determine whether the traction device speed is unreliable, wherein the traction device speed is determined as unreliable when the detected steering exceeds a predetermined threshold; and

when the location signal is determined to be lost and the traction device speed is determined to be unreliable, estimate the velocity of the machine based on the detected acceleration.

8. The velocity estimation system of claim 7, wherein the first signal is a GPS signal.

9. The velocity estimation system of claim 7, wherein the traction device speed is a track speed of the machine.

10. The velocity estimation system of claim 7, further including:

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

wherein the controller is further configured to estimate the velocity of the machine based on a detected traction device speed slip when the location signal is determined to be lost and the traction device speed is determined as not unreliable.

11. The velocity estimation system of claim 7, wherein the velocity of the machine is calculated using a Kalman filter.

12. The velocity estimation system of claim 11, 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.

13. 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, from a locating device, 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 indicated by the received location signal over a period of time;

determining a loss of the location signal;

detecting a traction device speed of the machine;

detecting an acceleration of the machine;

detecting a steering of the machine;

determining whether the traction device speed is unreliable, wherein the traction device speed is determined as unreliable when the detected steering exceeds a predetermined threshold; and

when the location signal is determined to be lost and the traction device determined to be unreliable, estimating the velocity of the machine based on the detected acceleration.

14. The non-transitory computer-readable storage medium of claim 13, wherein the location signal is a GPS signal and the traction device speed is a track speed of the machine.

15. The non-transitory computer-readable storage medium of claim 13, wherein the operations further include:

when the location signal is determined to be lost and the traction device speed is determined to be not unreliable, estimating the velocity of the machine based on a detected traction device speed slip.

16. The non-transitory computer-readable storage medium of claim 13, wherein the velocity of the machine is calculated using a Kalman filter.

17. The non-transitory computer-readable storage medium of claim 16, 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.