| 摘要 |
PURPOSE:To reduce cutter bite at a rapidly changing point of a model shape while enabling said point to be detected in an early stage by changing a reference value based on the amount of changes per unit time of a displacement signal from a tracer head for tracing a model surface. CONSTITUTION:Displacement signals epsilonx-epsilonz from a tracer head 1 is sampled in a sampling circuit 2 at every prescribed time, and a copying operation is performed in a copying arithmetic circuit 3 on the basis of said sampled vaues. And, a motor 5 is driven and controlled by an output from said circuit 3, and the tracer head 1 and a model 4 are relatively moved, allowing copying control to be performed. Here, the amount of changes per unit time of a displacement signal is estimated by a change amount detecting means 6 based on the above described sampled values, and a reference value is set by a reference value setting means 7 based on said amount of changes. And, when the difference, evaluated in a control means 8, between the above described amount of change and its reference value is more than prescribed value, the relative speed between both 1, 4 is controlled to be reduced. |
