Work machine

Abstract

An hydraulic excavator calculates an estimated excavation volume Va defined by a bucket claw tip position (first position) at an excavation start, a bucket claw tip position (second position) at an excavation end set in advance, a current landform, a first target surface, and a bucket width w. A second target surface is generated at a position superior to the first target surface when the estimated excavation volume Va exceeds a limit volume Vb; and the second target surface is generated at a position at which the excavation volume defined by the first position, the second position, the current landform, the second target surface, and the bucket width is closer to the limit volume Vb. The hydraulic actuators are controlled such that an operating range of a work implement is limited on the second target surface and to an area superior to the second target surface.

1 . A work machine comprising:
 a work implement having a bucket, an arm, and a boom;   a plurality of hydraulic actuators that drive the work implement;   operation devices that instruct the hydraulic actuators on operations; and   a controller configured to control the hydraulic actuators such that, during operations of the operation devices, an operating range of the work implement is limited on a predetermined first target surface and to an area superior to the first target surface, wherein   the controller includes:
 a storage section that stores position information of a current landform; 
 a bucket position calculation section that calculates a position of a claw tip of the bucket; 
 an estimated excavation volume calculation section that calculates an estimated excavation volume defined by a first position that assumes the position of the claw tip of the bucket calculated by the bucket position calculation section at an excavation start, a second position that assumes the position of the claw tip of the bucket at an excavation end set in advance, the current landform, the first target surface, and a width of the bucket; and 
 a target surface generation section that generates, when the estimated excavation volume exceeds a limit volume set in advance, a second target surface at a position superior to the first target surface, 
   the target surface generation section generates the second target surface at a position at which the excavation volume defined by the first position, the second position, the current landform, the second target surface, and the width of the bucket is closer to the limit volume, and   when the second target surface is generated, the controller controls the hydraulic actuators such that the operating range of the work implement is limited on the second target surface and to an area superior to the second target surface.   
     
     
         2 . The work machine according to  claim 1 , wherein
 the first position is the position of the claw tip of the bucket calculated by the bucket position calculation section when a crowding operation of the arm is input via the operation device.   
     
     
         3 . The work machine according to  claim 1 , further comprising:
 a current landform acquisition device that acquires the position information of the current landform, wherein   the controller further includes a current landform updating section that updates, when the estimated excavation volume is calculated by the estimated excavation volume calculation section, the position information of the current landform stored in the storage section using the position information of the current landform acquired by the current landform acquisition device.   
     
     
         4 . The work machine according to  claim 1 , wherein
 the controller further includes a current landform updating section that updates, when the position of the claw tip of the bucket calculated by the bucket position calculation section is disposed inferior to a position of the current landform stored in the storage section, the position information of the current landform stored in the storage section using position information of the claw tip of the bucket calculated by the bucket position calculation section.   
     
     
         5 . The work machine according to  claim 1 , wherein
 the limit volume is equal to or smaller than a double capacity of the bucket.