Research of an Open CNC System for MRF Machine Tool Based on UMAC
In order to use magnetorheological finishing (MRF) to accomplish ultra-precision machining of complex curve surfaces, an open computer numerical control (CNC) system based on universal motion and automation controller (UMAC) has been developed. The paper introduces the hardware structure of the system, elucidates the control algorithm and parameters tuning of PID + velocity/acceleration feed-forward + notch filter, and explains the design of a friendly human-machine interface (HMI) to satisfy the need of actual manufacturing and complicated numerical control. With the open CNC system, a 4mm-diameter circle is polished on the MRF experimental prototype with the contour error of 1.67% and the surface roughness Ra of 1.4nm. Experimental results prove that the open CNC system for the MRF machine tool meets the requirements of ultra-precision machining.