Discrete-Time Model Reference Control of Milling Forces under Fractional Order Holds. Part II: Extensions to Adaptive Control

In this paper, a novel discrete-time model-reference based control of the tool-work-piece interaction force in a milling process has been designed. The novelty of the scheme relies on the use of a fractional order hold (FROH) instead of a ZOH to obtain the discrete model of the plant. The additional degree of freedom provided by the FROH allows improve the closed-loop behavior of the time-varying unknown system by an adequate selection of its gain, as simulation results have pointed out.