Work machine and method for controlling work machine

Abstract

A work machine includes a vehicle body, a work implement movably supported relative to the vehicle body, an actuator connected to the work implement, and a controller. The actuator is configured to cause the work implement to move. The controller is configured to perform an automatic control to control the actuator so that a height of the work implement in a gravity direction is maintained even when a posture of the vehicle body changes, determine whether the work machine is in a non-working state in which the work machine does not perform work with the work implement, and stop the automatic control when the work machine is in the non-working state.

1 . A work machine comprising:
 a vehicle body:   a work implement movably supported relative to the vehicle body:   an actuator connected to the work implement, the actuator being configured to cause the work implement to move; and   a controller configured to
 perform an automatic control to control the actuator so that a height of the work implement in a gravity direction is maintained even when a posture of the vehicle body changes, 
 determine whether the work machine is in a non-working state in which the work machine does not perform work with the work implement, and 
 stop the automatic control when the work machine is in the non-working state. 
   
     
     
         2 . The work machine according to  claim 1 , further comprising:
 an operating device manually operable by an operator to cause the work implement to move,   the controller being configured to control the actuator according to a manual operation of the operating device upon stopping the automatic control.   
     
     
         3 . The work machine according to  claim 1 , wherein
 the vehicle body is configured to switch a travel mode between forward, reverse, and neutral, and   the controller is configured to determine whether the work machine is in the non-working state according to the travel mode of the vehicle body.   
     
     
         4 . The work machine according to  claim 3 , wherein
 the controller is configured to stop the automatic control when the travel mode is switched from forward to neutral or from neutral to reverse.   
     
     
         5 . The work machine according to  claim 1 , wherein
 the controller is configured to determine whether the work machine is in the non-working state according to a position of the work implement.   
     
     
         6 . The work machine according to  claim 5 , wherein
 the actuator includes a lift cylinder, the lift cylinder being configured to cause the work implement to move up and down, and   the controller is configured to stop the automatic control when a length of the lift cylinder is less than or equal to a predetermined length threshold.   
     
     
         7 . The work machine according to  claim 1 , wherein
 the controller is configured to
 acquire a vehicle speed of the work machine, and 
 stop the automatic control when the vehicle speed is greater than or equal to a predetermined speed threshold. 
   
     
     
         8 . The work machine according to  claim 1 , wherein
 the controller is configured to
 determine whether a predetermined reactivation condition is satisfied after the automatic control is stopped, and 
 reactivate the automatic control when the predetermined reactivation condition is satisfied. 
   
     
     
         9 . A method for controlling a work machine that includes a vehicle body, a work implement movably supported relative to the vehicle body, and an actuator connected to the work implement and configured to cause the work implement to move, the method comprising:
 performing an automatic control to control the actuator so that a height of the work implement in a gravity direction is maintained even when a posture of the vehicle body changes:   determining whether the work machine is in a non-working state in which the work machine does not perform work with the work implement; and   stopping the automatic control when the work machine is in the non-working state.   
     
     
         10 . The method according to  claim 9 , further comprising:
 acquiring an operation signal indicative of a manual operation from an operating device, the operating device being operable by an operator to cause the work implement to move: and   controlling the actuator according to the manual operation of the operating device upon stopping the automatic control.   
     
     
         11 . The method according to  claim 9 , wherein
 the vehicle body is configured to switch a travel mode between forward, reverse, and neutral, and   the method further comprises determining whether the work machine is in the non-working state according to the travel mode.   
     
     
         12 . The method according to  claim 11 , wherein
 the controller is configured to stop the automatic control when the travel mode is switched from forward to neutral or from neutral to reverse.   
     
     
         13 . The method according to  claim 9 , further comprising:
 determining whether the work machine is in the non-working state according to a position of the work implement.   
     
     
         14 . The method according to  claim 13 , wherein
 the actuator includes a lift cylinder, the lift cylinder being configured to cause the work implement to move up and down, and   the method further comprises stopping the automatic control when a length of the lift cylinder is less than or equal to a predetermined length threshold.   
     
     
         15 . The method according to  claim 9 , further comprising:
 acquiring a vehicle speed of the work machine; and   stopping the automatic control when the vehicle speed is greater than or equal to a predetermined speed threshold.   
     
     
         16 . The method according to  claim 9 , further comprising:
 determining whether a predetermined reactivation condition is satisfied after the automatic control is stopped; and   reactivating the automatic control when the predetermined reactivation condition is satisfied.