| 摘要 |
<p>When an arm end moves beyond a border line (K2) and into a speed reducing area (R1), a solenoid proportional pressure reducing valve (13) is actuated to reduce a pilot pressure and a speed of a first boom cylinder (1A) to thereby reduce a speed of the arm end, and when the arm end moves beyond a border line (K1) and into a recovery area (R2), a control gain block (200) calculates a recovery gain in accordance with a distance over which the arm end moves into the recovery area, and respective functions (204, 205, 206, 207, 208, 209) calculate feedback gains in accordance with an arm end speed at that time. These gains cause a second boom (2) to automatically dump in accordance with a distance over which the arm end moves into the recovery area, and an arm end speed at that time, and move and return an arm end position to the speed reducing area. Accordingly, an operation for moving a working front toward this side is performed smoothly to improve a work efficiency. <IMAGE></p> |
