Operational parameter determination systems and methods with gear shifting compensation

• US 8,818,650 B2
• Filed: 08/31/2012
• Issued: 08/26/2014
• Est. Priority Date: 08/31/2012
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Friend, Paul Russell, Fehr, Drew Alan, Willis, Frank Arthur
• Primary Examiner(s): Cheung, Mary
• Application Number:
  US13/601,218
• Publication Number:
  US 20140067213A1
• Time in Patent Office: 725 Days
• Field of Search: 701/50, 701/51, 701/53, 701/57
• US Class Current: 701/50
• CPC Class Codes: A01B 69/003 Steering or guiding of machines or implements pushed or pulled by or mounted on agricultural vehicles such as tractors, e.g. by lateral shifting of the towing connection
• CPC Class Codes: E02F 9/202 Mechanical transmission, e.g. clutches, gears clutches per se F16D, gears per se F16H
• CPC Class Codes: E02F 9/2079 Control of mechanical transmission for hydrostatic transmission or hydraulic torque converter E02F9/2253
• CPC Class Codes: F16H 2059/663 Road slope
• CPC Class Codes: F16H 2061/0078 Linear control, e.g. PID, state feedback or Kalman
• CPC Class Codes: F16H 61/0213 characterised by the method for generating shift signals

Abstract

An operational parameter determination system is disclosed. The operational parameter determination system may include an operational parameter predictor configured to calculate an a priori estimated operational parameter of the machine based on a previously estimated operational parameter. The operational parameter determination system may also include a gear shifting compensator configured to determine whether a gear shifting is in progress, and when the gear shifting is in progress, to output the a priori estimated operational parameter as a determined operational parameter. The operational parameter determination system may further include an operational parameter updater configured to, when the gear shifting is not in progress, receive a measured operational parameter of the machine, determine an a posteriori estimated operational parameter of the machine based on the a priori estimated operational parameter and the measured operational parameter, and output the a posteriori estimated operational parameter as the determined operational parameter.

Claims

1. A computer-implemented method of determining an operational parameter of a machine, the method comprising:

calculating an a priori estimated operational parameter of the machine based on a previously estimated operational parameter;

determining whether a gear shifting is in progress;

when the gear shifting is in progress, outputting the a priori estimated operational parameter as a determined operational parameter; and

when the gear shifting is not in progress;

measuring a measured operational parameter of the machine;

calculating an a posteriori estimated operational parameter of the machine based on the a priori estimated operational parameter and the measured operational parameter; and

outputting the a posteriori estimated operational parameter as the determined operational parameter.

2. The computer-implemented method of claim 1, wherein the a priori estimated operational parameter and the a posteriori estimated operational parameter are calculated using a Kalman filter.

3. The computer-implemented method of claim 2, wherein the determined operational parameter is used as an input to the Kalman filter.

4. The computer-implemented method of claim 1, wherein the operational parameter is an inclination angle of the machine, and the method further includes:

measuring a measured inclination angular rate;

calculating an a priori estimated inclination angle based on the measured inclination angular rate, a previously estimated inclination angle, and a previously estimated inclination angular rate bias;

determining whether a gear shifting is in progress;

when the gear shifting is in progress, outputting the a priori estimated inclination angle as a determined inclination angle; and

when the gear shifting is not in progress;

measuring a measured inclination angle of the machine;

calculating an a posteriori estimated inclination angle and a calculated inclination angular rate bias based on the a priori estimated inclination angle and the measured inclination angle; and

outputting the a posteriori estimated inclination angle as the determined inclination angle.

5. The computer-implemented method of claim 4, further including:

feeding back the determined inclination angle as the previously estimated inclination angle in the calculation of the a priori estimated inclination angle.

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

feeding back the calculated inclination angular rate bias as the previously estimated inclination angular rate bias in the calculation of the a priori estimated inclination angle.

7. The computer-implemented method of claim 1, wherein the operational parameter is a forward velocity of the machine, and the method further includes:

measuring a measured acceleration value;

calculating an a priori estimated forward velocity based on the measured acceleration value, a previously estimated forward velocity, and a previously estimated acceleration bias;

determining whether a directional gear shifting is in progress;

when the directional gear shifting is in progress, outputting the a priori estimated forward velocity as a determined forward velocity; and

when the directional gear shifting is not in progress;

measuring a measured velocity of the machine;

applying a sign to the measured velocity;

calculating an a posteriori estimated forward velocity and a calculated acceleration bias based on the a priori estimated inclination angle and the measured velocity; and

outputting the a posteriori estimated forward velocity as the determined forward velocity.

8. The computer-implemented method of claim 7, further including:

feeding back the determined forward velocity as the previously estimated forward velocity in the calculation of the a priori estimated forward velocity.

9. The computer-implemented method of claim 8, further including:

feeding back the calculated acceleration bias as the previously estimated acceleration bias in the calculation of the a priori estimated forward velocity.

10. An operational parameter determination system for determining an operational parameter of a machine, comprising:

an operational parameter predictor configured to calculate an a priori estimated operational parameter of the machine based on a previously estimated operational parameter;

a gear shifting compensator configured to determine whether a gear shifting is in progress, and when the gear shifting is in progress, to output the a priori estimated operational parameter as a determined operational parameter; and

an operational parameter updater configured to, when the gear shifting is not in progress;

receive a measured operational parameter of the machine;

determine an a posteriori estimated operational parameter of the machine based on the a priori estimated operational parameter and the measured operational parameter; and

output the a posteriori estimated operational parameter as the determined operational parameter.

11. The operational parameter determination system of claim 10, wherein the operational parameter predictor and the operational parameter updater are included in a Kalman filter.

12. The operational parameter determination system of claim 11, wherein the determined operational parameter is used as an input to the Kalman filter.

13. The operational parameter determination system of claim 10, further including:

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

the gear shifting compensator configured to determine whether a gear shifting is in progress, and when the gear shifting is in progress, to output the a priori estimated inclination angle as a determined inclination angle; and

an inclination angle updater configured to, when the gear shifting is not in progress;

receive a measured inclination angle of the machine;

determine an a posteriori estimated inclination angle of the machine based on the a priori estimated inclination angle and the measured inclination angle; and

output the a posteriori estimated inclination angle as the determined inclination angle.

14. The operational parameter determination system of claim 13, wherein the inclination angle predictor and the inclination angle updater are included in a Kalman filter.

15. The operational parameter determination system of claim 13, wherein the forward velocity predictor and the forward velocity updater are included in a Kalman filter.

16. The operational parameter determination system of claim 14, wherein the determined inclination angle is used as an input to the Kalman filter.

17. The operational parameter determination system of claim 14, wherein the determined forward velocity is used as an input to the Kalman filter.

18. The operational parameter determination system of claim 10, further including:

a forward velocity predictor configured to calculate an a priori estimated forward velocity of the machine based on a previously estimated forward velocity;

the gear shifting compensator configured to determine whether a directional gear shifting is in progress, and when the directional gear shifting is in progress, to output the a priori estimated forward velocity as a determined forward velocity; and

a forward velocity updater configured to, when the directional gear shifting is not in progress;

receive a measured forward velocity of the machine;

determine an a posteriori estimated forward velocity of the machine based on the a priori estimated forward velocity and the measured forward velocity; and

output the a posteriori estimated forward velocity as the determined inclination angle.

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

calculating an a priori estimated operational parameter of the machine based on a previously estimated operational parameter;

determining whether a gear shifting is in progress;

when the gear shifting is in progress, outputting the a priori estimated operational parameter as a determined operational parameter; and

when the gear shifting is not in progress;

measuring a measured operational parameter of the machine;

calculating an a posteriori estimated operational parameter of the machine based on the a priori estimated operational parameter and the measured operational parameter; and

outputting the a posteriori estimated operational parameter as the determined operational parameter.

20. The computer-readable storage device of claim 19, wherein the a priori estimated operational parameter and the a posteriori estimated operational parameter are calculated using a Kalman filter.