Earth shaping vehicle retrofitted with rear grading tool

Abstract

An earth shaping vehicle (ESV) includes a chassis and a rear earth shaping tool. The chassis drives the ESV through the site from a first location in the site to a second location in the site. The front earth shaping tool moves earth from the first location to the second location. The rear earth shaping tool grades a ground surface between first location and the second location. Sensors coupled to the rear excavation tool produce one or more signals representative of a position and an orientation of the rear tool relative to the ground surface of the site. A controller produces actuating signals to actuate the rear excavation tool to grade the ground surface based on the one or more signals representative of the position and the orientation of the rear tool.

What is claimed is: 
     
         1 . A tractor configured to move earth in a site, the tractor comprising:
 a chassis configured to drive the tractor through the site from a first location in the site to a second location in the site;   a rear earth shaping tool coupled to a rear end of the tractor, the rear earth shaping tool configured to grade a ground surface between first location and the second location, wherein a set of sensors are coupled to the rear excavation tool and are configured to produce one or more signals representative of a position and an orientation of the rear tool relative to the ground surface of the site; and   a controller communicatively coupled to the set of sensors and configured to produce actuating signals to actuate the rear excavation tool to grade the ground surface between the first location and the second location based on the one or more signals representative of the position and the orientation of the rear tool.   
     
     
         2 . The tractor of  claim 1 , wherein the rear earth shaping tool comprises a rigid framework and a curved member, the rigid framework configured to removably couple to the tractor and to support the curved member and the curved member configured to provide a surface of the rear earth shaping tool for grading the ground surface. 
     
     
         3 . The tractor of  claim 2 , wherein the rigid framework is coupled to the tractor by securing one or more attachment posts of the rigid framework to a ripper assembly of the tractor, the ripper assembly comprising one or more hydraulic cylinders configured to actuate the rear earth shaping tool. 
     
     
         4 . The tractor of  claim 2 , wherein the rigid framework comprises an upper piece and a lower piece with a leading edge oriented at angle towards the ground surface a, and wherein a surface of the curved member is curved along the orientation of the leading edge. 
     
     
         5 . The tractor of  claim 4 , wherein the curved member is secured to the leading edge of the lower piece and side edges of the upper piece. 
     
     
         6 . The tractor of  claim 4 , wherein the curved member is a moldboard with a leading edge configured to withstand a force exerted on the leading edge of the moldboard by the ground surface as the rear earth shaping tool grades the ground surface between the first location and the second location. 
     
     
         7 . The tractor of  claim 1 , wherein the tractor further comprises a front earth shaping tool coupled to a front end of the tractor, the front earth shaping tool configured to push earth in a forward direction from the first location to the second location and the rear earth shaping tool configured to pull earth on the ground surface in the forward direction from the first location to the second location. 
     
     
         8 . The tractor of  claim 1 , wherein the actuating signals comprise instructions to:
 adjust a leading edge of the rear earth shaping tool to a position in contact with the ground surface;   navigate the chassis forward between the first location and the second location; and   maintain the position of the leading edge of the rear earth shaping tool as the chassis navigates forward.   
     
     
         9 . The tractor of  claim 1 , wherein the actuating signals comprise instructions to:
 adjust a leading edge of the rear excavation tool to a first depth below the ground surface;   navigate the chassis along a first path beginning at the first location while maintaining the leading edge at the first depth;   navigate the chassis to a third location adjacent to the first location;   adjust the leading edge of the rear excavation tool to a second depth below the ground surface, wherein the second depth is different than the first depth; and   navigate the chassis along a second path beginning at the third location while maintaining the leading edge at the second depth.   
     
     
         10 . The tractor of  claim 1 , further comprising:
 a set of solenoids, wherein each solenoid is configured to actuate a corresponding hydraulic valve of the rear earth shaping tool to move the rear earth shaping tool towards the ground surface.   
     
     
         11 . An earth shaping vehicle (ESV) configured to move earth in a site, the ESV comprising:
 a chassis configured to drive the ESV through the site from a first location in the site to a second location in the site;
 a rear earth shaping tool coupled to a rear end of the ESV, the rear earth shaping tool configured to grade a ground surface between first location and the second location, wherein a set of sensors are coupled to the rear excavation tool and are configured to produce one or more signals representative of a position and an orientation of the rear tool relative to the ground surface of the site; and 
   a controller communicatively coupled to the set of sensors and configured to produce actuating signals to actuate the rear excavation tool to grade the ground surface between the first location and the second location based on the one or more signals representative of the position and the orientation of the rear tool.   
     
     
         12 . The ESV of  claim 11 , wherein the rear earth shaping tool comprises a rigid framework and a curved member, the rigid framework configured to removably couple to the ESV and to support the curved member and the curved member configured to provide a surface of the rear earth shaping tool for grading the ground surface. 
     
     
         13 . The ESV of  claim 12 , wherein the rigid framework is coupled to the ESV by securing one or more attachment posts of the rigid framework to an assembly of the ESV comprising one or more hydraulic cylinders configured to actuate the rear earth shaping tool. 
     
     
         14 . The ESV of  claim 12 , wherein the rigid framework comprises an upper piece and a lower piece with a leading edge oriented at an angle towards the ground surface a and wherein a surface of the curved member is curved along the orientation of the leading edge. 
     
     
         15 . The ESV of  claim 14 , wherein the curved member is secured to the leading edge of the lower piece and side edges of the upper piece. 
     
     
         16 . The ESV of  claim 14 , wherein the curved member is a moldboard with a leading edge configured to withstand a force exerted on the leading edge of the moldboard by the ground surface as the rear earth shaping tool grades the ground surface between the first location and the second location. 
     
     
         17 . The ESV of  claim 11 , wherein the ESV further comprises a front earth shaping tool coupled to a front end of the tractor, the front earth shaping tool configured to push earth in a forward direction from the first location to the second location and the rear earth shaping tool configured to pull earth on the ground surface in the forward direction from the first location to the second location. 
     
     
         18 . The ESV of  claim 11 , wherein the actuating signals comprise instructions to:
 adjust a leading edge of the rear earth shaping tool to a position in contact with the ground surface;   navigate the chassis forward between the first location and the second location; and   maintain the position of the leading edge of the rear earth shaping tool as the chassis navigates forward.   
     
     
         19 . The ESV of  claim 11 , wherein the actuating signals comprise instructions to:
 adjust a leading edge of the rear excavation tool to a first depth below the ground surface;   navigate the chassis along a first path beginning at the first location while maintaining the leading edge at the first depth;   navigate the chassis to a third location adjacent to the first location;   adjust the leading edge of the rear excavation tool to a second depth below the ground surface, wherein the second depth is different than the first depth; and   navigate the chassis along a second path beginning at the third location while maintaining the leading edge at the second depth.   
     
     
         20 . The ESV of  claim 7 , further comprising:
 a set of solenoids, wherein each solenoid is configured to actuate a corresponding hydraulic valve of the rear earth shaping tool to move the rear earth shaping tool towards the ground surface.