Abstract: The harmonic characteristics of a circle profile can be estimated by FFT,which, however, cannot be used in the case of a non-circular arc because the sampling points around the whole circle cannot be obtained this way. In this paper, a harmonic model of a circular arc based on RSM (response surface method) is built up; the morbidity of the model is studied; and the method to improve the model is advanced. By means of interpolation and iteration, RSM is combined with FFT to estimate the harmonic characteristics of a circular arc. As harmonic characteristics are formed in the manufacturing process and affect the performance of the work pieces and the measuring uncertainty, our research in this regard is of considerable importance to other researchers in the same field.

Key words: harmonic analysis, interpolation, RSM