Variable measurement step in 2-sliding control

Sliding mode is used in order to retain a dynamic system accurately at a gi ven constraint and features theoretically-infinite-frequency switching. Sta ndard sliding modes are known to feature finite time convergence, precise k eeping of the constraint and robustness with respect to internal and extern al disturbances. Having generalized the notion of sliding mode, higher orde r sliding modes preserve or generalize its main properties, improve its pre cision with discrete measurements and remove the chattering effect. However , in their standard form, most of higher order sliding controllers are sens itive to measurement errors. A special measurement step feedback is introdu ced in the present paper, which solves that problem without loss of precisi on. The approach is demonstrated on a so-called twisting algorithm. Its asy mptotic properties are studied in the presence of vanishing measurement err ors. A model illustration and simulation results are presented.