| 摘要 |
PURPOSE:To quicken bite detection time in time of high speed operation as well as to aim at reduction in a degree of biting, by making a slice level be compared with a time differentiation value in a displacement quantity smaller in proportion as a speed increases, while slowing down a copying speed at a time when the differentiation value goes beyond the level. CONSTITUTION:Slice levels SX and SZ in X and Z direction corresponding to a shaft speed are outputted from multipliers MP1 and MP2 of a slice level compensation circuit SLC1, and become smaller in proportion as the shaft speed grows larger and inputted into comparators CPX and CPZ. Here, when these slice levels SX and SZ become less than the specified speed, a biting quantity in time of low-speed operation can be made into the same quantity in the past in these levels SX and SZ are clamped to the set slice level S. Thus, since these slice levels SX and SZ are made to be the smallr the speedier in the shaft speed, when biting gets generating in time of high speed operation and shaft displacement quantities epsilonX and epsilonZ grow large, these quantities come to ¦epsilonX'¦>=SX or ¦epsilonZ'¦>=SZ so that a biting signal OCX or OCZ is generated out of the comparator CPX or CPZ and thereby biting is detected, thus the biting quantity in time of high speed operation is reduced. |
