Nc machining requires " interpolation " algorithms that accurately and efficiently generate sequences of reference position , distributed according to a prescribed feedrate function , along the tool paths . this paper present a systematic derivation of the proper taylor series coefficients for variable feedrate interpolators . when the path is ph curves , detailed formulations for instances are presented where the feedrate v is specified as a constant , the function of the time t , the arc length s and the local curvature k 对于nc加工要求插值算法沿着刀具路径准确、有效的生成参考点序列(根据预先指定的速率函数进行分布)的实际工程需要,本文系统地推导了变速率插值算子的泰勒系数,给出了当路径为ph曲线,速率v为常数,及时间t 、弧长s 、曲率k的函数时具体的插值算子。