A Circular Interpolation Algorithm for NC Machining Trace Control Based on Angle Approximation Theorem

. DDA（Digital Differential Analyzer）circular interpolation algorithm is often applied to NC（Numerical Control） machining trace control, due to the greater error accumulation in DDA interpolation algorithm, the maximum feed speed of machine tool is limited, and the interpolation algorithm is hardly satisfied with the requirements for high-precision and high-speed machining. To solve this problem, a new circular interpolation algorithm based on the angular approximation method was proposed, the fundamental rule, calculation program and calculating process were introduced, and then, this interpolation algorithm was compared with the other DDA interpolation algorithm in error accumulation. It is concluded from comparative analysis and practical application that the new interpolation algorithm does not exist any accumulative error in the speed and outline, the interpolation error is little, the algorithm is simple and easy to be realized as well.