Work vehicle control system, work vehicle control method, and work vehicle

Abstract

A control system for a work vehicle, which includes a vehicle body and work equipment that is changeable in height and pitch with respect to the vehicle body, includes a controller. The controller determines a switching point by referring to target displacement data indicating a target displacement of the height of the work equipment according to a movement amount of the work vehicle from a work start position. The controller determines whether or not the work vehicle has reached the switching point based on the movement amount of the work vehicle from the work start position. The controller outputs a command to change the pitch of the work equipment upon determining that the work vehicle has reached the switching point.

1 . A control system for a work vehicle including a vehicle body and work equipment that is changeable in height and pitch with respect to the vehicle body, the system comprising:
 a controller, the controller being configured to
 determine a switching point by referring to target displacement data indicating a target displacement of the height of the work equipment according to a movement amount of the work vehicle from a work start position, 
 determine whether or not the work vehicle has reached the switching point based on the movement amount of the work vehicle from the work start position, and 
 output a command to change the pitch of the work equipment upon determining that the work vehicle has reached the switching point. 
   
     
     
         2 . The control system for a work vehicle according to  claim 1 , wherein
 upon determining that the work vehicle has reached the switching point, the controller is further configured to output the command to change the pitch so as to tilt the work equipment rearward with respect to the vehicle body.   
     
     
         3 . The control system for a work vehicle according to  claim 1 , wherein
 the target displacement data indicates
 the target displacement that monotonically increases with an increase in the movement amount of the work vehicle within a range of 0 or greater and less than a predetermined value in a first region in which the movement amount of the work vehicle is less than a first distance, 
 the target displacement equal to the predetermined value in a second region in which the movement amount of the work vehicle is the first distance or greater and less than a second distance, and 
 the target displacement that monotonically decreases with an increase in the movement amount of the work vehicle within a range of 0 or greater and less than the predetermined value in a third region in which the movement amount of the work vehicle is the second distance or greater and less than a third distance, and 
   the switching point is located within a range of the second region and the third region.   
     
     
         4 . The control system for a work vehicle according to  claim 3 , wherein
 the switching point is a point spaced from the work start position by the second distance.   
     
     
         5 . The control system for a work vehicle according to  claim 3 , wherein
 the switching point is a point spaced from the work start position by the first distance.   
     
     
         6 . The control system for a work vehicle according to  claim 3 , wherein
 the switching point is a point spaced from the work start position by the third distance.   
     
     
         7 . The control system for a work vehicle according to  claim 1 , wherein
 upon determining that a bucket blade edge of the work equipment has reached the switching point, the controller is further configured to output the command to change the pitch of the work equipment.   
     
     
         8 . The control system for a work vehicle according to  claim 1 , wherein
 upon determining that a position of a center of gravity of the vehicle body has reached directly above the switching point, the controller is further configured to output the command to change the pitch of the work equipment.   
     
     
         9 . The control system for a work vehicle according to  claim 1 , wherein
 the controller is further configured to
 acquire current topography information indicating a current topography of a work target, 
 determine a target design surface displaced from the current topography in a vertical direction by referring to the target displacement data, and 
 output a command to change the height of the work equipment along the target design surface. 
   
     
     
         10 . The control system for a work vehicle according to  claim 9 , wherein
 the target design surface is located below the current topography.   
     
     
         11 . The control system for a work vehicle according to  claim 1 , wherein
 the controller is further configured to cause the work equipment to be lowered so as to cancel out a change in a height of a bucket blade edge of the work equipment caused by the command to change the pitch of the work equipment.   
     
     
         12 . A method for controlling a work vehicle including a vehicle body and work equipment that is changeable in height and pitch with respect to the vehicle body, the method comprising:
 determining a switching point by referring to target displacement data indicating a target displacement of the height of the work equipment according to a movement amount of the work vehicle from a work start position;   determining whether or not the work vehicle has reached the switching point based on the movement amount of the work vehicle from the work start position; and   outputting a command to change the pitch of the work equipment upon determining that the work vehicle has reached the switching point.   
     
     
         13 . The method for controlling a work vehicle according to  claim 12 , wherein
 upon determining that the work vehicle has reached the switching point, the command to change the pitch so as to tilt the work equipment rearward with respect to the vehicle body is output.   
     
     
         14 . The method for controlling a work vehicle according to  claim 12 , wherein
 upon determining that a bucket blade edge of the work equipment has reached the switching point, the command to change the pitch of the work equipment is output.   
     
     
         15 . The method for controlling a work vehicle according to  claim 12 , wherein
 upon determining that a position of a center of gravity of the vehicle body has reached directly above the switching point, the command to change the pitch of the work equipment is output.   
     
     
         16 . The method for controlling a work vehicle according to  claim 12 , further comprising
 acquiring current topography information indicating a current topography of a work target,   determining a target design surface displaced from the current topography in a vertical direction by referring to the target displacement data, and   outputting a command to change the height of the work equipment along the target design surface.   
     
     
         17 . The method for controlling a work vehicle according to  claim 16 , wherein
 the target design surface is located below the current topography.   
     
     
         18 . The method for controlling a work vehicle according to  claim 12 , wherein
 the work equipment is lowered to cancel out a change in a height of a bucket blade edge of the work equipment caused by the command to change the pitch of the work equipment.   
     
     
         19 . A work vehicle comprising:
 a vehicle body;   work equipment configured to be changeable in height and pitch with respect to the vehicle body; and   a controller, the controller being configured to
 determine a switching point by referring to target displacement data indicating a target displacement of the height of the work equipment according to a movement amount of the work vehicle from a work start position, 
 determine whether or not the work vehicle has reached the switching point based on the movement amount of the work vehicle from the work start position, and 
 output a command to change the pitch of the work equipment so as to tilt the work equipment rearward with respect to the vehicle body upon determining that the work vehicle has reached the switching point.