Control design and experimental results of sensor based direct process control for bar turning

Describes an in-process measurement and control system called radial error feedback geometric adaptive control (REFGAC) system for bar turning in CNC turning centers. The REFGAC system was design to compensate for the radial error caused by deflection under cutting force. To compensate for the radial error, Kalman filters for prediction together with PID control laws were designed, based on models of the deflection of the bar. Experimental results showed that the dimensional and geometric accuracy of the workpiece is substantially improved by this radial error feedback geometric adaptive control technique.