Cornuspline

Background

For the production of workpieces with high surface quality and contour accuracy with a short processing time and machine load at the same time, the selection of the method for setpoint generation is a crucial factor, especially in regard to the interpolation method. The G2-steady re-grinding method by means of piecewise defined clothoids (cornuspline) can contribute to the reduction of processing time and machine load.

Funded by  DFG.



Problem

Interpolation methods should create tangentially constant (G1) and ideally curvature constant (G2) toolpaths. Thus, a smooth course of the centripetal acceleration and jerkfree movements are to be achieved, so that a total deceleration at the block transitions can be avoided. Further, interpolation methods should allow the exact computability of the arc length, in order to obtain the optimal path length and consequently the best possible velocity profile. Current re-grinding methods of higher order (m>2) as, for example, cubic spline or B spline can only approximate the arc length.



Objective

The objective of this research project is to find out how accuracy and surface quality of workpieces can be improved and the machine load as well as the processing time be reduced. For this purpose the clothoids for path planning in NC controls will be used. A re-grinding method based on clothoids for linear circular interpolation is to be developed, because in contrast to the spline clothoids present the ideal transition between straight line and circle.