Real-time compensation of two-dimensional contour error in CNC machine tools

A real-time contour error compensation (RTCEC) system to improve contouring performance in CNC machine tools is proposed. The RTCEC system evaluates the contour error and modifies the reference position commands based on the computed contour error. Since the proposed compensation scheme can be executed on an external computer, it can be used in conventional CNC machine tools without modifying the interpolation and control algorithms of the CNC system. The compensation system, which introduces a new method for calculating the contour error in real-time without modifying the existing interpolation algorithm, has been implemented by integrating a PC with the existing CNC in a machining center. Experimental results on linear, circular and spiral contours demonstrate the performance of the proposed system.