Method and control unit for loading a work tool of a work machine

Abstract

A method for automated or automatic loading of a work tool of a work machine includes determining, as a function of operating conditions of the work machine, a probability of whether the work tool comes into or is in engagement with a material pile, and activating, in response to the determined probability being greater than a limit value, a load function for the automated or automatic loading. The method further includes ascertaining, when the load function is activated, a setpoint value for a lift position, a setpoint value for a tilt position, and a setpoint value for an accelerator pedal actuation as a function of a pressure measurement value on a hydrostat side of a power split transmission of the work machine, and ascertaining actuating signals for the automated or automatic loading as a function of a comparison of the ascertained setpoint values with corresponding actual values.

1 . A method for automated or automatic loading of a work tool of a work machine, wherein the work machine has a power split transmission having a hydrostat comprising hydrostatic units, the method comprising:
 determining, as a function of operating conditions of the work machine, a probability of whether the work tool of the work machine comes into or is in engagement with a material pile;   activating, in response to the determined probability being greater than a corresponding limit value, a load function for the automated or automatic loading of the work tool;   ascertaining, when the load function is activated, a setpoint value for a lift position of the work tool, a setpoint value for a tilt position of the work tool, and a setpoint value for an accelerator pedal actuation as a function of a pressure measurement value on a hydrostat side of the power split transmission, and   ascertaining actuating signals for the automated or automatic loading of the work tool as a function of a comparison of the ascertained setpoint values with corresponding actual values.   
     
     
         2 . The method according to  claim 1 , wherein determining the probability of whether the work tool of the work machine comes into or is in engagement with a material pile is determined as a function of an actual value of the lift position of the work tool, as a function of an actual value of the tilt position of the work tool, and as a function of an actual value of an output rotational speed or as a function of an actual value of a gradient of an output rotational speed. 
     
     
         3 . The method according to  claim 2 , wherein if when the actual value of the lift position is in a first range, the actual value of the tilt position is in a second range, and if-either the actual value of the output rotational speed is less than a corresponding limit value or the actual value of the gradient of the output rotational speed is greater than a corresponding limit value, the probability is determined to be greater than the corresponding limit value. 
     
     
         4 . The method according to  claim 1 , wherein the setpoint value for the lift position of the work tool, the setpoint value for the tilt position of the work tool, and the setpoint value for the accelerator pedal actuation are ascertained when the pressure measurement value on the hydrostat side of the power split transmission is greater than a corresponding limit value when the load function is activated. 
     
     
         5 . The method according to  claim 1 , further comprising displaying, in a display, the actuating signals in order to assist an operator in automatically loading the work tool. 
     
     
         6 . The method according to  claim 5 , wherein a first actuating signal indicates to the operator a tilting of the work tool, a second actuating signal indicates a lifting or lowering of the work tool, and a third actuating signal indicates an accelerator pedal actuation. 
     
     
         7 . The method according to  claim 1 , wherein the actuating signals are used for automatically controlling the work machine in order to relieve an operator through the automatic loading of the work tool. 
     
     
         8 . The method according to  claim 7 , wherein the automatic loading of the work tool is terminated by brake pedal actuation. 
     
     
         9 . The method according to  claim 1 , wherein the actuating signals for the automated or automatic loading of the work tool are ascertained as a function of a measurement value of a weight sensor of the work tool and/or as a function of a measurement value of an output-side sensor of the work machine. 
     
     
         10 . A control unit of a work machine the control unit being configured to carry out the method according to  claim 1 . 
     
     
         11 . The method according to  claim 1 , wherein the work machine is a wheel loader and the working tool is a bucket of the wheel loader.