Model Reference Adaptive Force Control in Milling

Abstract

This paper describes the design and implementation of a Model Reference Adaptive Controller (MRAC) for force control in milling. First, previous work in this area is discussed. Results from previous work on the performance of fixed gain process controllers is summarized. The design of an MRAC for force control in milling is described, including a discussion of the implementation issues of noise and computational speed. The adaptive controller was found to perform more satisfactorily than fixed gain controllers, but is difficult to implement and tune, primarily because of the unmodeled dynamics or measurement noise resulting from runout on the milling cutter. In this problem there was sufficient separation between the noise and the signal frequency that the noise could be filtered. However, the addition of the filter added additional dynamics to the system which reduced the overall performance from that expected from digital simulations.