System and method for determining ground stiffness

Abstract

A compactor is disclosed that has at least one roller drum configured to compact a work material. The compactor also has a memory storing a calibration system. The calibration system has a plurality of reference propelling power values, a plurality of reference ground stiffness values, and correlation information between the plurality of reference propelling power values and the plurality of reference ground stiffness values. The compactor further has a processor. The processor is configured to determine a propelling power of the compactor. The processor is also configured to compare the propelling power of the compactor with at least one of a plurality of reference propelling power values in the calibration system. The processor is further configured to determine a stiffness value of the work material based on a relationship between the propelling power of the compactor and the at least one of the plurality of reference propelling power values.

What is claimed is: 
     
         1 . A compactor, comprising:
 at least one roller drum configured to compact a work material; and   a controller configured to:
 determine a propelling power of the compactor; 
 access a calibration system including a reference propelling power value and correlation information between the reference propelling power value and a reference ground stiffness value; 
 compare the propelling power of the compactor with the reference propelling power value; and 
 determine a stiffness value of the work material based on a relationship between the propelling power of the compactor and the reference propelling power value; 
   wherein the compactor is configured to adjust a compaction effort based on the determined stiffness value.   
     
     
         2 . The compactor of  claim 1 , wherein the controller is further configured to determine the stiffness value of the work material based on a difference between the propelling power of the compactor and the reference propelling power value. 
     
     
         3 . The compactor of  claim 1 , wherein the controller is further configured to use a regression method to determine the stiffness value of the work material. 
     
     
         4 . The compactor of  claim 1 , wherein the controller is further configured to send a signal to a display indicating whether the stiffness value of the work material meets a predetermined threshold. 
     
     
         5 . The compactor of  claim 1 , wherein the controller is further configured to determine the stiffness value of the work material as a physical characteristic parameter of the work material with a unit of force per area. 
     
     
         6 . The compactor of  claim 1 , wherein the controller is further configured to compare at least one of a type, a density, or a level of moisture content of the work material with reference material information in the calibration system, the reference propelling power value being determined in part based on this comparison. 
     
     
         7 . The compactor of  claim 1 , wherein the calibration system includes data obtained from a field measurement or a laboratory test. 
     
     
         8 . The compactor of  claim 1 , wherein the propelling power is determined based on at least one of a ground speed of the compactor, a rolling resistance of the compactor, or a compactive energy delivered by the compactor to the work material. 
     
     
         9 . A compactor, comprising:
 at least one roller drum configured to compact a work material;   a memory storing a calibration system including a plurality of reference propelling power values, a plurality of reference ground stiffness values, and correlation information between the plurality of reference propelling power values and the plurality of reference ground stiffness values; and   a processor configured to:
 determine a propelling power of the compactor; 
 compare the propelling power of the compactor with at least one of the plurality of reference propelling power values in the calibration system; and 
 determine a stiffness value of the work material based on a relationship between the propelling power of the compactor and the at least one of the plurality of reference propelling power values. 
   
     
     
         10 . The compactor of  claim 9 , wherein the processor is further configured to determine the stiffness value of the work material based on a difference between the propelling power of the compactor and the at least one of the plurality of reference propelling power values. 
     
     
         11 . The compactor of  claim 9 , wherein the processor is further configured to use a regression method to determine the stiffness value of the work material. 
     
     
         12 . The compactor of  claim 9 , wherein the processor is further configured to send a signal to a display indicating whether the stiffness value of the work material meets a predetermined threshold. 
     
     
         13 . The compactor of  claim 9 , wherein the processor is further configured to determine the stiffness value of the work material as a physical characteristic parameter of the work material with a unit of force per area. 
     
     
         14 . The compactor of  claim 9 , wherein the processor is further configured to compare at least one of a type, a density, or a level of moisture content of the work material with reference material information in the calibration system, the at least one of the plurality of reference propelling power values being determined in part based on this comparison. 
     
     
         15 . The compactor of  claim 9 , wherein the calibration system includes data obtained from a field measurement or a laboratory test. 
     
     
         16 . A system for compacting at least one work material on a work site, comprising:
 a compactor having a variable compaction effort setting mechanism;   a memory storing a calibration system including a plurality of reference propelling power values, a plurality of reference ground stiffness values, and correlation information between the plurality of reference propelling power values and the plurality of reference ground stiffness values; and   a processor configured to:
 determine a propelling power of the compactor; 
 compare the propelling power of the compactor with at least one of the plurality of reference propelling power values in the calibration system; 
 determine a stiffness value of the at least one work material based on a relationship between the propelling power of the compactor and the at least one of the plurality of reference propelling power values; and 
 produce a ground stiffness map for the work site based on the determined stiffness value and location information. 
   
     
     
         17 . The system of  claim 16 , wherein the processor is further configured to compare the determined stiffness value to a desired stiffness value. 
     
     
         18 . The system of  claim 17 , wherein the processor is further configured to command the compactor to adjust a compaction effort to achieve the desired stiffness value. 
     
     
         19 . The system of  claim 18 , further comprising a second compactor having a second variable compaction effort setting mechanism. 
     
     
         20 . The system of  claim 19 , wherein the processor is further configured to determine a second stiffness value from the second compactor and produce the ground stiffness map for the work site based on the stiffness value determined from the compactor and the second stiffness value determined from the second compactor. 
     
     
         21 . The system of  claim 20 , wherein the processor is further configured to command the compactor and the second compactor to achieve the desired stiffness value.