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

A PC-based open architecture computer numerical controller (CNC) is introduced to control milling machines. The controller is implemented on two systems: (1) a single-axis high speed milling machine using analog control signals where the PC-based controller assumes all CNC functions 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 controller is implemented with the open architecture controller to maintain constant peak cutting force in the presence of uncertain machining conditions in end milling. An adaptive cross-coupling controller is also introduced to reduce tracking and contour error for a two-dimensional contour via the open architecture controller.