Constant Turning Force Adaptive Control Via Sliding Mode Control Design

Abstract

In the constant turning force adaptive control (CTFAC) system, the open-loop gain will vary and the stability cannot be assured when a cutting tool cuts a workpiece at various cutting depths or spindle operates in different speeds. In this paper, the spirit of sliding mode control is extended into discrete-time form to combine with parameter estimation having variable forgetting factor to stabilize the turning system against the variable gain and unmodeled dynamics, such as nonlinear perturbations, inaccurate measurements etc.