| 摘要 |
<p>A dual arm hydraulic excavator 200 has two front work devices A and B, which are provided on left and right sides of a front portion of an upper swing structure 3 and swingable in a top-bottom direction of the excavator 200. The front work devices A and B have arms 12a, 12b, booms 10a, 10b and working devices 20a, 20b, respectively. The average of angle ¸a of the arm 12a relative to the boom 10a and the angle ¸b of the arm 12b relative to the boom 10b is defined as an average arm angle ¸c. A range of the average arm angle, in which the average arm angle ¸c is larger than a predetermined threshold value ¸c2, is defined as an unstable range N. A range of the average arm angle, which is present on an inner side of the unstable range and adjacent to the unstable range, is defined as a stable state limit range M. When the average arm angle ¸c is in the stable state limit range M, a value of a drive signal is reduced to reduce operating speeds of the arms 12a and 12b. This can suppress a reduction in stability due to an increase in engine power required to operate two front work devices A and B.</p> |
