Toolpath Smoothing Based on Controlled NURBS Interpolation

Abstract

Based on cubic non-uniform B-spline curve constrained with tolerance band, a tool path smoothing approach is proposed for the purpose to achieve high-speed and high-precision machining of consecutive short line segments. According to a given tolerance band, the approach calculates the control polygon of the non-uniform cubic B-spline curve to transition the corners of the short line segments and obtains a GC2 continuous smooth transition for the tool path near the corners. The paper also designs an algorithm to realize the transition procedure. Compared with the reported similar approaches, this paper’s approach has advantages in reducing the fluctuations of machining speed and acceleration, enhancing machining  quality, and improving the processing efficiency and motion stability of machine tools. This approach is helpful for CNC system development, as well as CAD and CAM.