Smooth circular arc interpolation for planar free curves with tolerance control

摘要

Several circular arc curve-fitting methods have been proposed to overcome the drawbacks caused by a series of short linear movements in planar curve contouring machining. Almost all the previous circular arc curve-fitting methods assume thatovercut and undercut allowances are the same. This assumption is not practical in industry since the allowances can vary according to the characteristic of the part to be machined. The objective of this paper is to develop an enhanced circular arcinterpolation algorithm for planar free curves including tolerance control, which is easy and robust in practical implementation. An important property of the circular arc curve is that its offset curve is also another circular arc curve and can becalculated analytically. Using this property, the tolerance factors can be taken into account effectively in the present algorithm.