Automatic Depth and Traction Control for Ripping Machines

Abstract

A system and method of controlling a ripping operation is disclosed. The method includes lowering a ripper of a machine to a depth under a work surface. The method determines when a drawbar pull of the machine is at a drawbar pull target for the machine. When the drawbar pull is greater than the drawbar pull target, reducing power source torque of the machine from a first power source torque to a second power source torque.

We claim: 
     
         1 . A method of controlling a ripping operation, the method comprising:
 lowering a ripper of a machine to a depth under a work surface;   determining when a drawbar pull of the machine is at a drawbar pull target for the machine; and   when the drawbar pull is greater than the drawbar pull target, reducing power source torque of the machine from a first power source torque to a second power source torque.   
     
     
         2 . The method of  claim 1 , further comprising:
 when the second power source torque lowers the drawbar pull to less than or equal to the drawbar pull target, raising the power source torque to a torque greater than the second power source torque.   
     
     
         3 . The method of  claim 1 , further comprising:
 when the drawbar pull is greater than the drawbar pull target after reducing the power source torque of the machine to the second power source torque, raising the ripper and the power source torque of the machine to a torque greater than the second power source torque.   
     
     
         4 . The method of  claim 1 , wherein:
 the lowering of the ripper to a depth under the work surface is based at least on a target depth.   
     
     
         5 . The method of  claim 1 , further comprising:
 when the ripper is shallower than a target depth under the work surface and the drawbar pull is at the drawbar pull target, adjusting a depth of the ripper to maintain the drawbar pull.   
     
     
         6 . The method of  claim 1 , further comprising:
 receiving a signal from an automatic digging switch to set a target depth of the ripper.   
     
     
         7 . The method of  claim 1 , further comprising:
 inhibiting the ripper from being positioned deeper than a target depth.   
     
     
         8 . The method of  claim 1 , further comprising:
 setting a minimum and a maximum target depth for the ripper.   
     
     
         9 . A system for controlling a ripping operation, the system comprising:
 a power source configured to provide power to a machine;   an actuator configured to move a ripper of the machine;   a plurality of sensors configured to sense a position of the ripper;   a controller in communication with the power source, the actuator, and the plurality of sensors, the controller being configured to:   lower a ripper of a machine to a depth under a work surface;   determine when a drawbar pull of the machine is at a drawbar pull target for the machine; and   when the drawbar pull is greater than the drawbar pull target, reduce power source torque of the machine from a first power source torque to a second power source torque.   
     
     
         10 . The system of  claim 9 , wherein the controller is further configured to:
 when the second power source torque lowers the current drawbar pull to less than or equal to the drawbar pull target, raise the power source torque to a torque greater than the second power source torque.   
     
     
         11 . The system of  claim 9 , wherein the controller is further configured to:
 when the drawbar pull is greater than the drawbar pull target after reducing the power source torque of the machine to the second power source torque, raise the ripper and the power source torque of the machine to a torque greater than the second power source torque.   
     
     
         12 . The system of  claim 9 , wherein the controller is further configured to:
 lower the ripper to a depth calculated using the plurality of sensors configured to sense the position of the ripper under a work surface based on at least a target depth.   
     
     
         13 . The system of  claim 9 , wherein the controller is further configured to:
 when the ripper is shallower than a target depth under the work surface and the drawbar pull is at the drawbar pull target, adjust a depth of the ripper to maintain the drawbar pull.   
     
     
         14 . The system of  claim 9 , further comprising:
 a switch configured to toggle an automatic digging mode;   wherein the controller is further configured to:
 receive a signal from an automatic digging switch to set a target depth of the ripper. 
   
     
     
         15 . The system of  claim 9 , wherein the controller is further configured to:
 inhibit the ripper from being positioned deeper than a target depth.   
     
     
         16 . The system of  claim 9 , wherein the controller is further configured to:
 setting a minimum and a maximum target depth for the ripper.   
     
     
         17 . A system for controlling a ripping operation, the system comprising:
 a plurality of sensors configured to sense a position of a material engaging implement;   a controller in communication with the plurality of sensors, the controller being configured to:
 lower a ripper of a machine to a depth under a work surface; 
 determine when a drawbar pull of the machine is at a drawbar pull target for the machine; and 
 when the drawbar pull is greater than the drawbar pull target, reduce power source torque of the machine from a first power source torque to a second power source torque. 
   
     
     
         18 . The system of  claim 17 , wherein:
 the material engaging implement is a ripper.   
     
     
         19 . The system of  claim 17 , wherein the controller is further configured to:
 when the second power source torque lowers the current drawbar pull to less than or equal to the drawbar pull target, raise the power source torque to a torque greater than the second power source torque.   
     
     
         20 . The system of  claim 17 , wherein the controller is further configured to:
 when the drawbar pull is greater than the drawbar pull target after reducing the power source torque of the machine to the second power source torque, raise the ripper and the power source torque of the machine to a torque greater than the second power source torque.