Work machine and method for controlling work machine

Abstract

A work machine includes: a hydraulic cylinder for steering; an operation apparatus that receives an input of an operation command from an operator to drive the hydraulic cylinder for steering; a control valve that controls an amount of driving of the hydraulic cylinder for steering; and a controller that outputs a command current that causes the control valve to operate in response to the operation command of the operation apparatus. The controller executes a calibration mode for correcting the command current corresponding to the operation command of the operation apparatus and causing the control valve to operate. In the calibration mode, the controller cuts off the command current to the control valve when the operation apparatus is in a neutral position.

1 . A work machine comprising:
 a hydraulic cylinder for steering;   an operation apparatus that receives an input of an operation command from an operator to drive the hydraulic cylinder for steering;   a control valve that controls an amount of driving of the hydraulic cylinder for steering; and   a controller that outputs a command current that causes the control valve to operate in response to the operation command of the operation apparatus, wherein   the controller has a calibration mode of outputting the command current and performing calibration of the command current, and   in the calibration mode, the controller starts the calibration based on at least one condition that the operation command is sensed, and stops outputting the command current based on at least one condition that the operation command is not sensed.   
     
     
         2 . The work machine according to  claim 1 , wherein
 the operation command being not sensed refers to a case in which the operation apparatus is in a neutral position.   
     
     
         3 . The work machine according to  claim 1 , further comprising
 a steering spool that adjusts an amount of supply of hydraulic oil to be supplied to the hydraulic cylinder for steering, wherein   the control valve adjusts a position of a spool of the steering spool.   
     
     
         4 . The work machine according to  claim 3 , wherein
 the controller determines whether the operation command of the operation apparatus is equal to or larger than a first threshold value, and when the operation command of the operation apparatus is equal to or larger than the first threshold value, the controller increases a value of the command current and stores a command current when the spool reaches a prescribed position,   the controller calculates a correction value of the command current corresponding to the operation command of the operation apparatus based on a value of the stored command current, and   the controller determines whether the operation command of the operation apparatus is equal to or larger than a second threshold value, and when the operation command of the operation apparatus is not equal to or larger than the second threshold value, the controller sets the value of the command current to an initial value.   
     
     
         5 . The work machine according to  claim 4 , wherein
 the controller increases the value of the command current and stores a first command current when the spool reaches a first prescribed position,   the controller increases the value of the command current and stores a second command current when the spool reaches a second prescribed position, and   when the spool reaches the second prescribed position, the controller sets the value of the command current to the initial value.   
     
     
         6 . The work machine according to  claim 4 , wherein
 the controller increases the command current at a constant rate of increase with passage of time, the command current being a current that causes the control valve to operate in response to the operation command of the operation apparatus.   
     
     
         7 . The work machine according to  claim 4 , wherein
 the controller sets a target current in accordance with the operation command of the operation apparatus, and adjusts the command current to increase at a prescribed rate of increase with respect to the set target current.   
     
     
         8 . The work machine according to  claim 1 , further comprising
 a detector that detects an articulation angle that changes in accordance with driving of the hydraulic cylinder for steering, wherein   in the calibration mode, the controller starts the calibration mode when the articulation angle satisfies a prescribed condition, and stops outputting the command current when the articulation angle does not satisfy the prescribed condition.   
     
     
         9 . A method for controlling a work machine, the method comprising:
 receiving an input of an operation command of an operation apparatus from an operator to drive a hydraulic cylinder for steering;   outputting a command current that causes a control valve to operate in response to the operation command, the control valve being a valve that controls an amount of driving of the hydraulic cylinder for steering; and   outputting the command current and performing calibration of the command current, wherein   the performing calibration includes:
 starting the calibration based on at least one condition that the operation command is sensed; and 
 stopping outputting the command current based on at least one condition that the operation command is not sensed.