The calculation of path interval and the avoidance of collision for the machining of free-form surface

The calculation of path interval and the avoidance of collision is a necessary process for the machining of free-form surface. This calculation has crucial influence on the precision and efficiency of the machining surface. In this paper, a polynomial curve approximate to the intersection curve is obtained through Chebyshev polynomial interpolation; Based on this polynomial curve's character, which reflects its curvature and curvature variation, different approxim ate algorithms are adopted to calculate the path interval and avoid collision. By this way, the precision of tool-path planning is greatly improved, furthermore, the burden of calculation is not evidently added. In the other word, the calculation efficiency is greatly improved under the condition of ensuring high precision tool-path planning.