The Fine Interpolation Circuit Based on the Counter/timer;

In this dissertation, Field Programmable Gate Arrays (FPGA) chip is studied to develop and design the fine interpolation chip.

An algorithm of coarse and fine interpolation applied to the CNC system has been come up with in this paper,where by time-cutting precise algorithm,coarse interpolation has been made and fine interpolation has been implemented using parameter cubic spline interpolation.

The interpolation arithmetic speed, feed speed and interpolation accuracy are the most important index of arc interpolation algorithm, though the arc interpolation algorithm has a lot, but feed speed and interpolation accuracy are not very ideal.

The application of time-sharing interpolation principle in open-loop CNC system is discussed in the following aspects:the hardware and software structure of system ;the interpolation accuracy and interpolation speed.

This article has analyzed when uses chord length method interpolation cubic parameter spline curves,the factors of feed rate and radius of curvature to the interpolation precision\'s influence,using the curve fitting method separately obtains interpolation outline error E and feed rate F,between radius of curvature R function relationship E=E(F) and E=E(R).

Combined a equal arc length interpolation with interpolation precision requirement,realized the feed speed vary according to the curve curvature changed.