Machine and method of determining suitability of work material for compaction

• US 7,623,951 B2
• Filed: 04/06/2006
• Issued: 11/24/2009
• Est. Priority Date: 04/06/2006
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Corcoran, Paul T., Congdon, Thomas M.
• Primary Examiner(s): Tran; Dalena
• Application Number:
  US11/399,174
• Publication Number:
  US 20070239336A1
• Time in Patent Office: 1,328 Days
• Field of Search: 701/50, 701/35, 701/1, 73/78, 738/18, 404/125, 404/126, 250/34.8
• US Class Current: 701/50
• CPC Class Codes: E01C 19/288 adapted for monitoring characteristics of the material being compacted, e.g. indicating resonant frequency, measuring degree of compaction, by measuring values, detectable on the roller; using detected values to control operation of the roller, e.g. automatic adjustment of vibration responsive to such measurements
• CPC Class Codes: E02D 1/022 by investigating mechanical properties of the soil E02D1/027 takes precedence
• CPC Class Codes: E02D 3/02 Improving by compacting E02D3/11 takes precedence; compacting soil locally before or while forming foundations E02D27/26, E02D27/28

Abstract

A method of operating a compactor includes determining a value indicative of a compaction state of a region of work material after each of a plurality of compactor passes, and triggering a compaction fault condition if an incipient compaction response satisfies aberrant compaction criteria. A machine includes an electronic controller configured to trigger a compaction fault condition responsively to sensor input signals indicative that aberrant compaction criteria are satisfied by an incipient compaction response of a work material.

Claims

1. A method of operating a compactor machine comprising the steps of:

determining a value indicative of a compaction state of a region of work material after each of a plurality of compactor passes, the determined values defining an incipient compaction response of the region of work material;

determining if the incipient compaction response satisfies aberrant compaction criteria; and

triggering a compaction fault condition, if aberrant compaction criteria are satisfied.

2. The method of claim 1 further comprising the step of moving the compactor machine across the region of work material via a plurality of passes, wherein the step of determining a value indicative of a compaction state includes sensing values indicative of relative compaction during each of said compactor passes.

3. The method of claim 2 wherein the step of determining a value indicative of a compaction state includes sensing a rolling resistance of the compactor machine during each of the passes across the region of work material.

4. The method of claim 2 wherein the step of determining if the incipient compaction response satisfies aberrant compaction criteria comprises the step of fining a compaction response curve to the determined values.

5. The method of claim 4 wherein fitting a compaction response curve to the determined values comprises fining a nonlinear compaction response curve.

6. The method of claim 4 wherein:

the step of determining if the incipient compaction response satisfies aberrant compaction criteria comprises a step of determining a slope of an initial segment of the compaction response curve; and

the step of triggering a compaction fault condition comprises triggering a compaction fault condition based at least in part on the determined slope.

7. The method of claim 6 further comprising the step of determining a compaction suitability range for the slope of the initial curve segment, wherein the step of determining if the incipient compaction response satisfies aberrant compaction criteria comprises determining if the slope of the initial curve segment is outside of the compaction suitability range.

8. The method of claim 7 wherein the step of triggering a compaction fault condition comprises triggering a low cohesion fault condition, including a step of determining the slope of the initial segment of the compaction response curve is shallower than the compaction suitability range, where the compaction response curve is a load bearing capacity versus compactor pass number curve.

9. The method of claim 7 wherein the step of triggering a compaction fault condition comprises triggering a low moisture fault condition, including a step of determining the slope of the initial segment of the compaction response curve is steeper than the compaction suitability range, where the compaction response curve is a load bearing capacity versus compactor pass number curve.

10. The method of claim 4 wherein:

fining a compaction response curve to the determined values comprises fining a nonlinear compaction response curve; and

the step of determining if the incipient compaction response satisfies aberrant compaction criteria further comprises a step of comparing the determined values with the compaction response curve.

11. The method of claim 10 wherein the step of comparing the determined values with the compaction response curve includes comparing the determined values with corresponding points on the compaction response curve, including a step of calculating a sum of errors.

12. The method of claim 10 further comprising the step of triggering one of a first and a second decision path responsively to a comparison of the determined values with corresponding points on the compaction response curve.

13. The method of claim 12 further comprising the step of estimating a number of compactor passes necessary to achieve a target compaction state, if the first decision path is triggered.

14. The method of claim 13 further comprising the step of triggering an excess moisture fault condition, including the step of determining the estimated number of compactor passes necessary to achieve the target compaction state exceeds a desired number.

15. The method of claim 12 wherein:

the step of determining whether the incipient compaction response satisfies aberrant compaction criteria includes a step of determining whether the work material is in an overcompacted state, if the second decision path is triggered; and

the step of triggering a compaction fault condition comprises triggering an unfit compaction fault condition, if the work material is not in an overcompacted state.

16. The method of claim 4 further comprising the step of comparing the compaction response curve with at least one reference curve defined by an equation associated with aberrant compaction criteria.

17. A machine comprising:

a frame having at least one rotatable compacting unit coupled therewith;

at least one sensor operable to output a signal indicative of a compaction state of a region of a work material after each of a plurality of passes across the region by said rotatable compacting unit; and

an electronic controller coupled with said at least one sensor and configured to receive sensor inputs from said at least one sensor defining an incipient compaction response of the region of work material, said electronic controller further being configured to trigger a compaction fault condition if the incipient compaction response satisfies aberrant compaction criteria.

18. The machine of claim 17 wherein said electronic controller is further configured to determine a compaction response curve responsively to the plurality of input signals.

19. The machine of claim 18 wherein:

said compaction response curve is a relative compaction versus number of compactor passes curve;

said electronic controller is configured to compare values associated with the sensor inputs with corresponding values on said compaction response curve, and to determine a slope of an initial segment of said compaction response curve;

said electronic controller is further configured to trigger a compaction fault condition responsively to at least one of, a comparison of the values associated with the sensor inputs with the corresponding values and the slope of the initial segment of the compaction response curve, and configured to trigger a compaction suitability condition responsively to a compaction fault condition not being triggered; and

said electronic controller is further configured to generate an operator perceptible signal, responsively to at least one of a triggered fault condition and a triggered compaction suitability condition.

20. An electronic controller for a compactor machine configured to determine an incipient compaction response of a region of a work material based on a plurality of compaction state sensor inputs, and further configured to trigger a compaction fault condition if the incipient compaction response satisfies aberrant compaction criteria.