CONTROL OF CUTTING FORCE FOR END MILLING PROCESSES USING AN EXTENDED MODEL-REFERENCE ADAPTIVE-CONTROL SCHEME

In this work an extended Model Reference Adaptive Control (MRAC) techn ique is used to control the cutting force of an end milling process. T he technique incorporates Zero Phase Error Tracking Control (ZPETC) in to the MRAC system. The extended MRAC controller remains stable even i n the presence of marginally stable and non-minimum phase process zero s. A modified recursive least-square estimation algorithm is used for on-line parameter identification. Simulation results are presented to compare the extended MRAC controller to the standard MRAC controller. A microprocessor system is used to implement adaptive force control of a single-input single-output milling process where the microprocessor monitors the system cutting forces and controls the desired feedrate. A constant cutting force is maintained in the presence of time-varyin g plant gains and a high random component of the output force. Experim ental results are presented for standard MRAC and extended MRAC contro llers for comparison.