A smooth and undistorted toolpath interpolation method for 5-DoF parallel kinematic machines

Comparing with classical serial machining center, Parallel Kinematic Machines (PKMs) are displaying superiority in coupling rotational motion control, for which the tilt-and-torsion (T&T) angle was developed as a powerful research tool. However, this rotation modality is not widely used in manufacturing scenarios due to the lack of associated interpolation algorithm, which therefore impedes the application of PKMs. In this work, a modified spline method is designed to interpolate 5-axis PKM toolpath described by T&T angle. Quintic splines are constructed in both positional and orientational trajectories for smoothness requirement, and the interpolation quality is further reinforced by anti-distortion strategy and coordinating reparameterization spline. Simulation based on actual toolpath and machine model prove that the proposed algorithm realizes the smoothness of acceleration in all toolpath components, decreases the shock to the system, and reduces the surface error after cutting. The results indicate that the interpolation method in this paper can provide new algorithm for PKMs with T&T angle and promote their development in the industrial manufacturing and production.