System for interpolating an arc for a numerical control system

摘要

The coordinates (X.sub.n+1 Y.sub.n+1) of an arc to be traced at time t. sub.n+1 are preliminary calculated using the coordinates (X. sub.n Y.sub.n) at time t.sub.n, the radius (r) of the arc and a specified length l.sub. n during the time t.sub.n+1 -t.sub.n, thus the number of the calculations required for tracing an arc is considerably reduced and a low speed digital element which is cheap can be utilized in the present arc interpolation system. The formula for obtaining the coordinates is; ##EQU1## The asymptotic change of the above formulae and the apparatus according to the asymptotic formulae is also possible.