Work machine

Abstract

The purpose of the present invention is to provide a work machine equipped with an excavation assistance function capable of preventing unintended deep excavation while reducing the complexity handled by an operator. A control device for a work machine according to the present invention includes: an excavation operation determination unit that determines whether or not an excavation operation by an operator has been started; a height lower limit setting unit that sets the height of a lower limit plane that defines the downward movement bound of a bucket during the excavation operation; and an excavation operation assistance unit that controls a raising operation of a boom such that the tip end of the bucket does not dip below the lower limit plane during the excavation operation. The height lower limit setting unit calculates the height of the lowest point that can be reached by the tip end of the bucket when an arm or the bucket revolves downward from the posture of a work device when it has been determined that the excavation operation has started, and sets the height of the lower limit plane to be between the height of the tip end of the bucket when it has been determined that the excavation operation has started and the height of the lower limit plane.

Claims

1. A work machine comprising: a work device rotatably attached to a machine body and having a boom, arm and bucket; a posture detection device for detecting the posture of the work device; an operation detection device for detecting operator operation information for the work device; and a control device for assisting the operator's operation of the work device, wherein the control device includes: an excavation operation determination unit that determines whether or not the operator's excavation operation to instruct the work machine to excavate an object with the bucket has started based on the detection results of the posture detection device and the operation detection device; a lower limit height setting unit that sets the height of a lower limit surface that defines the downward movement limit of the bucket during the excavation operation; and an excavation operation support unit that controls the raising movement of the boom so that the tip of the bucket does not enter below the lower limit surface during the excavation operation, wherein the lower limit height setting unit calculates the lowest point that the tip of the bucket can reach when the arm or the bucket rotates downward from the posture of the work device when it is determined that the excavation operation has started, A work machine characterized in that the height of the lower limit surface is set between the height of the tip of the bucket and the height of the lowest point when it is determined that the excavation operation has started.

2. The work machine according to claim 1, wherein the bucket is rotatably connected to the tip of the arm, and the excavation operation determination unit determines whether or not the excavation operation has been started based on the amount of operation of the arm or the bucket by the operator in the cloud direction and the positional relationship between the ground surface of the machine body and the tip of the arm.

3. The work machine according to claim 2, characterized in that the lower limit height setting unit sets the height of the lower limit surface to a height midway between the height of the tip of the bucket and the height of the lowest point when it is determined that the excavation operation has started.

4. The work machine according to claim 2, characterized in that the lower limit height setting unit sets the height of the lower limit surface to a predetermined amount below the height of the tip of the bucket when it is determined that the excavation operation has started.

5. The work machine according to claim 4, characterized in that the lower limit height setting unit changes the predetermined amount according to the height of the tip of the bucket when it is determined that the excavation operation has started.

6. The work machine according to claim 2, characterized in that when the bucket comes into contact with the object to be excavated, the height of the tip of the bucket at the time it is determined that the excavation operation has started is set to the height of the lower limit surface.

7. The work machine according to claim 1, further comprising a display device that displays a figure indicating the lower limit surface at the height of the lower limit surface set by the lower limit height setting unit.

8. The work machine according to claim 1, further comprising a switch that outputs a signal indicating that the excavation operation has been started by the operator's operation, wherein the excavation operation determination unit determines whether or not the excavation operation has been started based on the signal output from the switch.

9. The work machine according to claim 1, further comprising a communication device for communicating with a remote control device, wherein the communication device receives operation information transmitted from the remote control device and outputs it to the control device, and the control device controls the work machine in accordance with the operation information transmitted from the remote control device.

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