Inclination detection systems and methods

• US 9,145,144 B2
• Filed: 09/28/2011
• Issued: 09/29/2015
• Est. Priority Date: 09/28/2011
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Friend, Paul Russell, Fehr, Drew Alan, Willis, Frank Arthur
• Primary Examiner(s): Chen, Shelley
• Application Number:
  US13/247,368
• Publication Number:
  US 20130079949A1
• Time in Patent Office: 1,462 Days
• Field of Search: 701/1
• US Class Current: 1/1
• CPC Class Codes: B60W 2030/043 about the roll axis
• CPC Class Codes: B60W 2520/105 Longitudinal acceleration
• CPC Class Codes: B60W 40/076 Slope angle of the road
• CPC Class Codes: B60Y 2200/25 Track vehicles
• CPC Class Codes: B60Y 2200/411 Bulldozers, Graders

Abstract

An inclination detection system is disclosed. The inclination detection system may have an inclination angle predictor configured to calculate an a priori estimated inclination angle of the machine based on a previously estimated inclination angle, and a measurement variance calculator configured to calculate a measurement variance of the a priori estimated inclination angle based on a non-gravitational acceleration of the machine. The inclination detection system may also have an inclination angle sensor configured to measure a measured inclination angle of the machine, and an inclination angle updater configured to determine an a posteriori estimated inclination angle of the machine based on the a priori estimated inclination angle, the measurement variance of the a priori estimated inclination angle, and the measured inclination angle.

Claims

1. A computer-implemented method of detecting an inclination of a machine comprising:

calculating an a priori estimated inclination angle of the machine based on a previously estimated inclination angle;

calculating a measurement variance of the a priori estimated inclination angle based on a non-gravitational acceleration of the machine;

measuring a measured inclination angle of the machine; and

determining an a posteriori estimated inclination angle of the machine based on the a priori estimated inclination angle, the measurement variance of the a priori estimated inclination angle, and the measured inclination angle.

2. The computer-implemented method of claim 1, further including:

calculating the non-gravitational acceleration of the machine based on the a priori estimated inclination angle of the machine.

3. The computer-implemented method of claim 1, further including:

calculating an estimated acceleration of the machine by subtracting an acceleration bias from a measured acceleration of the machine; and

calculating the non-gravitational acceleration of the machine by subtracting, from the estimated acceleration of the machine, an acceleration due to gravity.

4. The computer-implemented method of claim 3, wherein the acceleration due to gravity is defined as g*sin({circumflex over (θ

)}⁻

) where g is a conventional acceleration due to gravity and {circumflex over (θ

)}⁻

is the a priori estimated inclination angle of the machine.

5. The computer-implemented method of claim 1, further including:

calculating the non-gravitational acceleration of the machine based on acceleration values of the machine along three axes.

6. The computer-implemented method of claim 5, wherein the non-gravitational acceleration of the machine is determined by comparing a magnitude of a vector including the acceleration values along the three axes to values on a sphere representing the magnitude of acceleration due to gravity.

7. The computer-implemented method of claim 1, wherein the a priori estimated inclination angle and the a posteriori estimated inclination angle are calculated using a Kalman filter.

8. The computer-implemented method of claim 7, wherein the measurement variance of the a priori estimated inclination angle is used as an input to the Kalman filter.

9. An inclination detection system for detecting an inclination of a machine comprising:

an inclination angle predictor configured to calculate an a priori estimated inclination angle of the machine based on a previously estimated inclination angle;

a measurement variance calculator configured to calculate a measurement variance of the a priori estimated inclination angle based on a non-gravitational acceleration of the machine;

an inclination angle sensor configured to measure a measured inclination angle of the machine;

an inclination angle updater configured to determine an a posteriori estimated inclination angle of the machine based on the a priori estimated inclination angle, the measurement variance of the a priori estimated inclination angle, and the measured inclination angle.

10. The inclination detection system of claim 9, wherein the measurement variance calculator is further configured to calculate the non-gravitational acceleration of the machine based on the a priori estimated inclination angle of the machine.

11. The inclination detection system of claim 9, wherein the measurement variance calculator is further configured to:

calculate an estimated acceleration of the machine by subtracting an acceleration bias from a measured acceleration of the machine; and

calculate the non-gravitational acceleration of the machine by subtracting, from the estimated acceleration of the machine, an acceleration due to gravity.

12. The inclination detection system of claim 9, wherein the measurement variance calculator is further configured to calculate the non-gravitational acceleration of the machine based on acceleration values of the machine along three axes.

13. The inclination detection system of claim 12, wherein the measurement variance calculator is further configured to calculate the non-gravitational acceleration of the machine by comparing a magnitude of a vector including the acceleration values along the three axes to values on a sphere representing the magnitude of acceleration due to gravity.

14. The inclination detection system of claim 9, wherein the inclination angle predictor and the inclination angle updater are included in a Kalman filter.

15. The inclination detection system of claim 14, wherein the measurement variance of the a priori estimated inclination angle is used as an input to the Kalman filter.

16. A computer-readable storage device storing instructions for determining an inclination angle of a machine, the instructions causing one or more computer processors to perform operations comprising:

calculating an a priori estimated inclination angle of the machine based on a previously estimated inclination angle;

calculating a measurement variance of the a priori estimated inclination angle based on a non-gravitational acceleration of the machine;

receiving a measured inclination angle of the machine; and

determining an a posteriori estimated inclination angle of the machine based on the a priori estimated inclination angle, the measurement variance of the a priori estimated inclination angle, and the measured inclination angle.

17. The computer-readable storage device according to claim 16, the instructions further causing the one or more computer processors to perform operations including:

calculating the non-gravitational acceleration of the machine based on the a priori estimated inclination angle of the machine.

18. The computer-readable storage device according to claim 16, the instructions further causing the one or more computer processors to perform operations including:

calculating an estimated acceleration of the machine by subtracting an acceleration bias from a measured acceleration of the machine; and

calculating the non-gravitational acceleration of the machine by subtracting, from the estimated acceleration of the machine, an acceleration due to gravity.

19. The computer-readable storage device according to claim 18, wherein the acceleration due to gravity is defined as g*sin({circumflex over (θ

)}⁻

), where g is a conventional acceleration due to gravity and {circumflex over (θ

)}⁻

is the a priori estimated inclination angle of the machine.

20. The computer-readable storage device according to claim 16, the instructions further causing the one or more computer processors to perform operations including:

calculating the non-gravitational acceleration of the machine based on acceleration values for the machine along three axes.