| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic tilling-depth control device which is prevented from a phenomenon that undulations or continuous irregularities occur in tillage traces in a farm field, thereby to make the evenness of the farm field satisfactory.SOLUTION: A control unit 19 controls the rise and fall of a tiller 3 connected to a running machine body 1, to a set tilling depth on the basis of the detection result of a depth sensor 8. A first insensitive band on the rising side and the falling side is set by adding and subtracting a first predetermined value to and from a target value or the reference of the rising or falling value. When the detected value of the depth sensor 8 deviates from the upper limit or the lower limit of the first insensitive band, the rising output or the falling output of the tiller 3 is performed. Moreover, a second predetermined value smaller than the first predetermined value is added to or subtracted from the target value or the reference of the rising output is set. When the detected value of the depth sensor 8 enters the upper limit or the lower limit of the second insensitive zone, moreover, the rising output or the falling output of the tiller 3 is stopped, and the insensitive band width on the rising side of the first insensitive band is made larger than the insensitive band width of the falling side. |
