MODELING AND CONTROL OF CNC MACHINES USING A PC-BASED OPEN-ARCHITECTURE CONTROLLER

A PC-based open architecture computer numerical controller (CNC) is in troduced to control milling machines. The controller is implemented on two systems: (1) a single-axis high speed milling machine using analo g control signals where the PC-based controller assumes all CNC functi ons and (2) a three-axis milling machine controlled by digital signals where the existing CNC continues to monitor peripheral functions but the PC-based system generates the reference commands for the axes and spindle. System models are developed using sinusoidal inputs to build the frequency response functions of each axis drive. An experimental c ontroller is implemented with the open architecture controller to main tain constant peak cutting force in the presence of uncertain machinin g conditions in end milling. An adaptive cross-coupling controller is also introduced to reduce tracking and contour error for a two-dimensi onal contour via the open architecture controller.