Implementation of a sensor-based supervision system for CNC machinin

A sensor-based supervision system for CNC machining was implemented on a White Sunstrand Series 20 Omnimil machining center. An interface was created between the Automation Intelligence FlexMate CNC controller and a supervisory computer. A set of supervision subroutines was created that allowed monitoring and control schemes running on the supervisory computer to take control of the machine tool based on sensor data sampled during the metal cutting process.;Four supervision schemes were implemented as part of the on-line machine supervision system. The Adaptive Control scheme monitored the vibration of the metal cutting process and varied the feedrate to achieve stable cuts. The Tool Breakage Detection scheme stopped the cutting process when a broken tool was detected. The Chatter Recognition and Control scheme detected chatter, a self-regenerative vibration phenomenon, and automatically selected a new stable spindle speed. The Spindle Torque Overload Detection scheme stopped the feed if a variation in the spindle speed indicated that the cutting tool was about to stall in the workpiece.;Also created was an off-line machine evaluation system which was used to measure Transfer Functions on the machine, sample data from sensors, and analyze machine tool chatter. The off-line system was used to evaluate the performance of both the supervision subroutines and the monitoring and control schemes in the on-line supervision system.;Each of the individual monitoring and control schemes was demonstrated in a series of cutting tests on the Omnimil. It was shown that the schemes were able to identify various disturbances in the cutting process, and take corrective action using the supervision subroutines to issue commands to the machine tool controller.;The research demonstrates the feasibility of having an external supervisory computer work in cooperation with a machine tool controller. This suggests that future CNC controllers should directly support this kind of interface.