Implement position calibration using compaction factor

• US 9,567,731 B2
• Filed: 05/18/2015
• Issued: 02/14/2017
• Est. Priority Date: 05/18/2015
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Darukhanavala, Carl P., Becicka, Troy Kenneth
• Primary Examiner(s): Heinle, Courtney
• Assistant Examiner(s): SHUDY, ANGELINA M
• Application Number:
  US14/715,073
• Publication Number:
  US 20160340872A1
• Time in Patent Office: 638 Days
• Field of Search: 701/33.1, 701/50
• US Class Current: 1/1
• CPC Class Codes: E02F 3/844 for positioning the blade, e.g. hydraulically
• CPC Class Codes: E02F 9/264 Sensors and their calibration for indicating the position of the work tool
• CPC Class Codes: G01D 18/002 Automatic recalibration G01D18/008 takes precedence
• CPC Class Codes: G07C 5/0841 Registering performance data recording measured values G01D; information storage G11B

Abstract

A method, system, and non-transitory computer-readable storage medium for calibrating an implement actuation sensor of a machine are disclosed. The method may include calculating a first elevation value of an implement of the machine. The method may include calculating a second elevation value of a ground-engaging device of the machine. The method may include, in response to determining that the machine is spreading, adjusting the second elevation value based on a compaction factor to determine an adjusted second elevation value. The method may further include determining a first elevation difference value based on a difference between the first elevation value and the adjusted second elevation value. The method may further include calibrating the implement actuation sensor based on the determined difference.

Claims

1. A method for calibrating an implement actuation sensor of a machine, comprising:

receiving, by a controller, a first elevation value of an implement of the machine from the implement actuation sensor;

receiving, by the controller, a second elevation value of a ground-engaging device of the machine from a pose-system;

determining, by the controller, whether a first set of conditions is satisfied;

in response to the first set of conditions being satisfied, determining, by the controller, whether the machine is spreading;

in response to determining that the machine is spreading, adjusting, by the controller, the second elevation value based on a compaction factor to determine an adjusted second elevation value;

determining, by the controller, a first elevation difference value based on a difference between the first elevation value and the adjusted second elevation value; and

calibrating, by the controller, the implement actuation sensor based on the determined difference; and

directing, by the controller, movement of the implement based on the calibration.

2. The method of claim 1, wherein calculating the first elevation value includes:

calculating an offset of an implement cutting edge from an origin in a local coordinate frame of the machine, and

translating the offset from the local coordinate frame to a gravity coordinate frame of the machine.

3. The method of claim 1, wherein determining whether the machine is spreading includes:

comparing the first elevation value with a terrain elevation value where the first elevation value and the terrain elevation value correspond to a first terrain location, and

determining that the machine is spreading when the first elevation value is greater than the terrain elevation value.

4. The method of claim 3, wherein the second elevation value of the ground-engaging device is calculated when a predetermined point on the ground-engaging device crosses the first terrain location.

5. The method of claim 4, wherein the first elevation difference value is calculated using the equation:

elev_diff=blade_elev−

(((blade_elev−

terrain_elev)*CF)+track_elev)

where elev_diff is the first elevation difference value, blade_elev is the first elevation value, terrain_elev is the terrain elevation value, CF is the compaction factor, and track_elev is the second elevation value.

6. The method of claim 1, further including:

in response to determining that the machine is not spreading, calculating a second elevation difference value based on a difference between the first elevation value and the second elevation value.

7. The method of claim 1, wherein the first set of conditions is not satisfied if the machine is steering or if a service brake is activated.

8. A implement position control system in a machine, comprising:

an implement actuation sensor associated with an implement of the machine; and

a controller in communication with the implement actuation sensor, the controller configured to;

receive a first elevation value of an implement of the machine from the implement actuation sensor;

receive a second elevation value of a ground-engaging device of the machine from a pose-system;

determine whether a first set of conditions is satisfied;

in response to the first set of conditions being satisfied, determine whether the machine is spreading;

in response to determining that the machine is spreading, adjust the second elevation value based on a compaction factor to determine an adjusted second elevation value;

determine a first elevation difference value based on a difference between the first elevation value and the adjusted second elevation value;

calibrate the implement actuation sensor based on the determined difference; and

direct movement of the implement based on the calibration.

9. The system of claim 8, wherein calculating the first elevation value includes:

calculating an offset of an implement cutting edge from an origin in a local coordinate frame of the machine, and

translating the offset from the local coordinate frame to a gravity coordinate frame of the machine.

10. The system of claim 8, wherein determining whether the machine is spreading includes:

comparing the first elevation value with a terrain elevation value where the first elevation value and the terrain elevation value correspond to a first terrain location, and

determining that the machine is spreading when the first elevation value is greater than the terrain elevation value.

11. The system of claim 10, wherein the second elevation value of the ground-engaging device is calculated when a predetermined point on the ground-engaging device crosses the first terrain location.

12. The system of claim 11, wherein the first elevation difference value is calculated using the equation:

elev_diff=blade_elev−

(((blade_elev−

terrain_elev)*CF)+track_elev)

where elev_diff is the first elevation difference value, blade_elev is the first elevation value, terrain_elev is the terrain elevation value, CF is the compaction factor, and track_elev is the second elevation value.

13. The system of claim 8, wherein the controller is further configured to calculate a second elevation difference value based on a difference between the first elevation value and the second elevation value in response to determining that the machine is not spreading.

14. The system of claim 8, wherein the first set of conditions is not satisfied if the machine is steering or if a service brake is activated.

15. A non-transitory computer-readable storage medium storing instructions that enable a computer to execute a method for calibrating an implement actuation sensor of a machine, the method comprising:

receiving, by a controller, a first elevation value of an implement of the machine;

receiving, by the controller, a second elevation value of a ground-engaging device of the machine;

determining, by the controller, whether a first set of conditions is satisfied;

in response to the first set of conditions being satisfied, determining, by the controller, whether the machine is spreading;

in response to determining that the machine is spreading, adjusting, by the controller, the second elevation value based on a compaction factor to determine an adjusted second elevation value;

determining, by the controller, a first elevation difference value based on a difference between the first elevation value and the adjusted second elevation value; and

calibrating, by the controller, the implement actuation sensor based on the determined difference; and

directing, by the controller, movement of the implement based on the calibration.

16. The non-transitory computer-readable storage medium of claim 15, wherein calculating the first elevation value includes:

calculating an offset of an implement cutting edge from an origin in a local coordinate frame of the machine, and

translating the offset from the local coordinate frame to a gravity coordinate frame of the machine.

17. The non-transitory computer-readable storage medium of claim 15, wherein determining whether the machine is spreading includes:

comparing the first elevation value with a terrain elevation value where the first elevation value and the terrain elevation value correspond to a first terrain location, and

determining that the machine is spreading when the first elevation value is greater than the terrain elevation value.

18. The non-transitory computer-readable storage medium of claim 17, wherein the second elevation value of the ground-engaging device is calculated when a predetermined point on the ground-engaging device crosses the first terrain location.

19. The non-transitory computer-readable storage medium of claim 18, wherein the first elevation difference value is calculated using the equation:

elev_diff=blade_elev−

(((blade_elev−

terrain_elev)*CF)+track_elev)

where elev_diff is the first elevation difference value, blade_elev is the first elevation value, terrain_elev is the terrain elevation value, CF is the compaction factor, and track_elev is the second elevation value.

20. The non-transitory computer-readable storage medium of claim 15, further including:

in response to determining that the machine is not spreading, calculating a second elevation difference value based on a difference between the first elevation value and the second elevation value.