| abstract |
The invention relates to servo-driven computer-numerically-controlled systems of the type adapted to receive part program instructions defining a desired path (110) of relative movement between a tool (12) and a workpiece (W), wherein the path may include an interior or exterior curved portion to be effected by coordinated linear movement of machine members along at least two orthogonal linear axes (X, Y). The invention provides apparati and methods for correcting path radius errors (E) to facilitate rapid and accurate movement along the curve. The invention carries out path radius correction by generating position commands (52, 53, 54 and 55) received by the servo (69) using corrected radius data (46), the difference between which and the desired radius (R) to be machined compensates for at least a portion of the path radius error (E) that would otherwise be generated by the servo (69). |