MACHINE NAVIGATION SYSTEM UTILIZING SCALE FACTOR ADJUSTMENT

• US 20140145876A1
• Filed: 11/29/2012
• Published: 05/29/2014
• Est. Priority Date: 11/29/2012
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: FRIEND, Paul Russell, Willis, Frank Arthur
• Granted Patent: US 9,128,183 B2
• Time in Patent Office: Days
• US Class Current: 342/357.35
• CPC Class Codes: G01C 22/00 Measuring distance traversed on the ground by vehicles, persons, animals or other moving solid bodies, e.g. using odometers, using pedometers
• CPC Class Codes: G01S 19/52 Determining velocity

Abstract

A machine navigation system and method for estimating velocity of a machine is disclosed. The method may include receiving, from an odometer, a first signal indicative of a distance traveled by the machine and calculating a scale factor to compensate for an error associated with the first signal. The method may further include determining whether a second signal indicative of a location of the machine is received by the machine and selectively adjusting the scale factor using machine parameters to generate an adjusted scale factor, where selectively adjusting may be performed based on whether the second signal is received by the machine. The method may further include estimating the velocity of the machine based on the first signal and the adjusted scale factor.

Claims

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

receiving, from an odometer, a first signal indicative of a distance traveled by the machine;

calculating a scale factor to compensate for an error associated with the first signal;

determining that a second signal indicative of a location of the machine is not received by the machine;

responsive to the determination that the second signal is not received by the machine, selectively adjusting the scale factor using machine parameters to generate an adjusted scale factor; and

estimating, using a processor, the velocity of the machine based on the first signal and the adjusted scale factor.

2. The method of claim 1, wherein the second signal is a global positioning system signal.

3. The method of claim 1, wherein the first signal includes an indication of a number of rotations of a wheel of the machine in a predetermined period.

4. The method of claim 1, wherein:

the machine parameters includes at least one of a payload of the machine, a tire pressure of the machine, a slip of the machine, a slope of the machine, and an outside temperature.

5. The method of claim 4, wherein generating the adjusted scale factor further includes determining an adjustment for the scale factor based on a lookup table for the machine parameters.

6. The method of claim 1, wherein selectively adjusting the scale factor includes:

determining a first distance traveled by the machine using the scale factor and the first signal;

determining a second distance traveled by the machine using the second signal when the second signal is received by the machine; and

generating the adjusted scale factor based on a difference between the first distance and the second distance.

7. The method of claim 6, wherein:

the first distance and the second distance are calculated using a Kalman filter;

the first distance is calculated in a propagation stage of the Kalman filter; and

the second distance is calculated in a measurement update stage of the Kalman filter.

8. A system for estimating velocity of a machine, comprising:

an odometer configured to generate a first signal indicative of a distance traveled by the machine;

a locating device that includes a processor configured to receive a second signal indicative of a location of the machine;

a sensor configured to provide parametric values associated with performance of the machine; and

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

calculate a scale factor to compensate for an error associated with the first signal;

determine that the second signal is not received by the locating device;

responsive to the determination that the second signal is not received by the locating device, selectively adjust the scale factor using the parametric values to generate an adjusted scale factor; and

estimate the velocity of the machine based on the first signal and the adjusted scale factor.

9. The system of claim 8, wherein the second signal is a global positioning system signal.

10. The system of claim 8, wherein the first signal includes an indication of a number of rotations of a wheel of the machine in a predetermined period.

11. The system of claim 8, wherein:

the parametric values include at least one of a payload of the machine, a tire pressure of the machine, a slip of the machine, a slope of the machine, and an outside temperature.

12. The system of claim 11, wherein the controller is configured to adjust the scale factor by determining an adjustment for the scale factor based on a lookup table for the parametric values.

13. The system of claim 8, wherein the controller is configured to selectively adjust the scale factor by:

determining a first distance traveled by the machine using the scale factor and the first signal;

determining a second distance traveled by the machine using the second signal when the second signal is received by the locating device; and

adjusting the scale factor based on a difference between the first distance and the second distance.

14. The system of claim 13, wherein the controller is further configured to:

determine the first distance and the second distance using a Kalman filter;

calculate the first distance in a propagation stage of the Kalman filter; and

calculate the second distance in a measurement update stage of the Kalman filter.

15. A non-transitory computer-readable storage medium storing instructions for enabling a processor to execute a method of estimating velocity of a machine, the method comprising:

receiving, from an odometer, a first signal indicative of a distance traveled by the machine;

calculating a scale factor to compensate for an error associated with the first signal;

determining that a second signal indicative of a location of the machine is received by the machine;

responsive to the determination that the second signal is not received by the machine, selectively adjusting the scale factor using machine parameters to generate an adjusted scale factor; and

estimating the velocity of the machine based on the first signal and the adjusted scale factor.

16. The non-transitory computer-readable storage medium of claim 15, wherein the second signal is a global positioning system signal.

17. The non-transitory computer-readable storage medium of claim 15, wherein the first signal includes an indication of a number of rotations of a wheel of the machine in a predetermined period.

18. The non-transitory computer-readable storage medium of claim 15, wherein:

the machine parameters includes at least one of a payload of the machine, a tire pressure of the machine, a slip of the machine, a slope of the machine, and an outside temperature.

19. The non-transitory computer-readable storage medium of claim 18, wherein generating the adjusted scale factor further includes determining an adjustment for the scale factor based on a lookup table for the machine parameters.

20. The non-transitory computer-readable storage medium of claim 15, wherein selectively adjusting the scale factor includes:

determining a first distance traveled by the machine using the scale factor and the first signal;

determining a second distance traveled by the machine using the second signal when the second signal is received by the machine; and

generating the adjusted scale factor based on a difference between the first distance and the second distance.