Apparatus and method for precision control during grading operations of a work machine

Abstract

A work machine and method for grading a ground surface may include a frame, a ground-engaging attachment, an attachment coupler coupling the ground-engaging attachment to the frame, an actuator enabling movement of the ground-engaging attachment, an adjustable linkage to adjust a position of the ground-engaging attachment relative to the frame, an adjustable linkage, a sensor, and a controller. The adjustable linkage adjusts a position of the ground-engaging attachment relative to the frame. The adjustable linkage comprises of a first portion and a second portion, an enclosure encircling the second portion wherein the enclosure creates an annular chamber between the enclosure and the second portion. A sensor is coupled to the annular chamber and measures a pressure in the chamber. A controller may be configured to monitor the sensor signal, and perform one or more actions based on the sensor signal.

What is claimed is: 
     
         1 . A work machine comprising:
 a frame;   a ground-engaging attachment;   an attachment coupler coupling the ground-engaging attachment to the frame;   an actuator enabling movement of the ground-engaging attachment;   an adjustable linkage to adjust a position of the ground-engaging attachment relative to the frame, adjustable linkage comprising a first portion and a second portion, an enclosure encircling the second portion, the enclosure creating an annular chamber between the enclosure and the second portion;   a sensor coupled to the annular chamber, the sensor measuring a pressure in the annular chamber and creating a sensor signal based on the pressure; and   a controller configured to
 monitor the sensor signal; 
 perform one or more actions based on the sensor signal. 
   
     
     
         2 . The work machine of  claim 1  wherein the pressure is indicative of a load on the ground-engaging attachment. 
     
     
         3 . The work machine of  claim 1  wherein the annular chamber is partitioned into a first annular chamber and a second annular chamber, the sensor measuring a first pressure in the first annular chamber and a second pressure in the second annular chamber, wherein the sensor signal is based on a pressure differential between the first pressure and the second pressure. 
     
     
         4 . The work machine of  claim 1  wherein the annular chamber is filled with an incompressible fluid. 
     
     
         5 . The work machine of  claim 1  wherein the second portion of the adjustable linkage is floating within the enclosure. 
     
     
         6 . The work machine of  claim 1  further comprising:
 a ball joint coupling the ground-engaging attachment to the attachment coupler at a second location, the ball joint enabling the ground-engaging attachment to pivot about a point, wherein pivoting the ground-engaging attachment about the ball joint creates a proportionate force on the adjustable linkage. 
 
     
     
         7 . The work machine of  claim 1  wherein actuation of the actuator moves the ground-engaging attachment in a direction of pitch. 
     
     
         8 . The work machine of  claim 1  wherein actuation of the actuator moves the ground-engaging attachment in a direction of roll and yaw. 
     
     
         9 . The work machine of  claim 1  wherein the actions comprise of determining a target grade and sending a command to move the ground-engaging attachment toward the target grade. 
     
     
         10 . The work machine of  claim 1  wherein the actions comprise of modifying one or more of an engine speed, a transmission torque, a brake pressure, and a travel speed. 
     
     
         11 . The work machine of  claim 1  wherein the annular chamber comprises of an end chamber, the end chamber formed between an end wall of the second portion and a base of the enclosure. 
     
     
         12 . An adjustable linkage for a work machine coupled to a ground-engaging attachment, the adjustable linkage comprising:
 a frame;   a ground-engaging attachment;   an attachment coupler coupling the ground-engaging attachment to the frame;   an actuator enabling movement of the ground-engaging attachment;   an adjustable linkage to adjust a position of the ground-engaging attachment with respect to the attachment coupler, adjustable linkage comprising a first portion and a second portion, an enclosure encircling the second portion, the enclosure creating an annular chamber between the enclosure and the second portion;   a sensor coupled to the annular chamber, the sensor measuring a stress on the annular chamber and creating a sensor signal based on the stress;   a ball joint coupling the ground engaging-attachment to the attachment coupler at a second location, the ball joint enabling the ground-engaging attachment to pivot about a point, wherein pivoting the ground-engaging attachment about the ball joint creates a proportionate force on the adjustable linkage; and   a controller configured to
 monitor the sensor signal, and 
 modifying one or more of an engine speed, a transmission torque, a brake pressure, and a travel speed if the sensor signal is outside an optimal range. 
   
     
     
         13 . The adjustable linkage of  claim 12 , wherein the annular chamber comprises of an end chamber, the end chamber formed between an end wall of the second portion and a base of the enclosure, and the sensor located within the end chamber. 
     
     
         14 . A method of operating a work machine with a ground-engaging attachment, the method comprising:
 sensing a load on a pitch link by a sensor, the pitch link coupled to the work machine on a first end, and coupled to the ground-engaging attachment on a second end;   sending a sensor signal based on the load, the sensor signal indicative of a load on the ground-engaging attachment;   determining if the sensor signal is within an optimal range; and   performing one or more actions based on the sensor signal.   
     
     
         15 . The method of  claim 14  wherein the sensor measures a hydraulic pressure differential between a first annular chamber and a second annular chamber of the pitch link. 
     
     
         16 . The method of  claim 14  wherein the pitch link is coupled to a top portion of the ground-engaging attachment, the ground-engaging attachment having a cutting edge on a bottom portion of the ground-engaging attachment, and
 a ball joint couples the ground engaging-attachment to the work machine and a lower portion of the ground-engaging attachment, the ball joint enabling the ground-engaging attachment to pivot about a point, wherein pivoting the ground-engaging attachment about the ball joint creates a proportionate force on the pitch link. 
 
     
     
         17 . The method of  claim 14  wherein the actions comprise of determining a target grade and sending a command signal to move the ground-engaging attachment toward the target grade 
     
     
         18 . The method of  claim 14  wherein actions comprise of modifying one or more of an engine speed, a transmission torque, a brake pressure, and a travel speed. 
     
     
         19 . The method of  claim 14  wherein the sensor measures a stress on an end chamber of the annular chamber, the end chamber formed between an end wall of the second portion and a base of the enclosure, with the sensor located within the end chamber. 
     
     
         20 . The work machine of  claim 1  wherein actuation of the actuator moves the ground-engaging attachment in a direction of pitch.